{"paper_id":"09518d0b-3e52-4348-8555-c07dddf5396d","body_text":"Page | 1 \n \nCharacteristics of women diagnosed with endometriosis in England: a \ndecade of diagnoses, 2011-2021 \n \nHannah Bunk1, Emma Campbell 1, Gemma C Sharp2, Vahé Nafilyan1, Daniel Ayoubkhani 1, & Isobel L \nWard1 (*) \nCorresponding author (*) isobel.ward@ons.gov.uk \n1. Office for National Statistics, UK Government  \n2. Department of Psychology, Faculty of Health and Life Sciences, University of Exeter \nAbstract  \nIntroduction  \nEndometriosis is a chronic disease and the second most common gynaecological condition in the UK, \naffecting approximately 1.5 million women. It is characterised by the growth of endometrial tissue \noutside the uterus, causing varying symptoms and having far reaching socioeconomic impacts. We \nutilise population level hospital admissions data and Census 2011 to examine the characteristics of \nwomen diagnosed with endometriosis in England. \nMethods \nUsing a retrospective cohort design, we used Hospital Episode Statistics (HES) between 2011 and \n2021, we linked health data to detailed sociodemographic information from Census 2011, providing \nindividual population-level information on self-reported characteristics. Our outcome of interest was \nan endometriosis diagnosis in hospital. Our exposures were age on Census Day (five-year age bands), \nethnic group, Index of Multiple Deprivation (IMD) decile, household National Statistics Socio-\neconomic Classification (NS-SEC), highest qualification, country of birth, main language, self-reported \ngeneral health, self-reported disability, rural/urban classification, region, and upper tier local \nauthority (UTLA). We calculated crude and age-standardised rates, and odds of receiving a diagnosis \nusing logistic regression models adjusted sequentially for age and health. \nResults \nOur results highlight differences in underlying prevalence of endometriosis by sociodemographic \ncharacteristic, as well as capturing differences in access to services for women receiving a diagnosis \nof endometriosis in an NHS hospital. The likelihood of receiving an endometriosis diagnosis was \nhighest in the \"White British\", \"Black Caribbean\" and \"Mixed White and Black Caribbean\" ethnic \ngroups, and lowest in the \"Chinese\", \"Arab\" and \"Black African\" ethnic groups. Women living in the \nmost and least deprived areas were least likely to have an endometriosis diagnosis, possibly \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \nNOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.\n\nPage | 2 \n \nreflecting lower access to healthcare services in the most deprived group and more use of private \nhealthcare in the least deprived group. Women self-reporting to be in bad health, or disabled, were \nmore likely to have had an endometriosis diagnosis compared those in very good health or non-\ndisabled women, respectively. \nConclusions \nOur results demonstrate significant sociodemographic differences between groups of women \nreceiving an endometriosis diagnosis in England. These results should be used to inform healthcare \npolicies to better support groups of women who are most affected by endometriosis and barriers to \nreceiving a diagnosis. Subsequent work should explore presentations in primary care, as well as the \nbroader socioeconomic ramifications of endometriosis. \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 3 \n \nResearch in context  \nWhat is already known on this topic \nEndometriosis is a common gynaecological condition which has debilitating impacts across many \ndomains, including physical, psychological, social and economic. It is estimated to affect 1 in 10 \nreproductive age women in England, however evidence on the differences in endometriosis \ndiagnosis by sociodemographic characteristics is lacking.   \nWhat this study adds \nOur study utilises population-level Census and HES data for England to estimate crude and age-\nstandardised rates of endometriosis diagnosis, and odds of receiving an endometriosis diagnosis by a \nrange of sociodemographic characteristics. We estimate the prevalence of an endometriosis \ndiagnosis to be approximately 2% of reproductive age women in our linked population, with an \naverage age at diagnosis of 35 years. Women living in the most and least deprived areas were least \nlikely to have an endometriosis diagnosis; this possibly reflects less access to healthcare services in \nthe most deprived group and more use of private healthcare in the least deprived group. The \nlikelihood of receiving an endometriosis diagnosis was highest in the \"White British\", \"Black \nCaribbean\", and \"Mixed White and Black Caribbean\" ethnic groups, and lowest in the \"Chinese\", \n\"Arab\", and \"Black African\" ethnic groups. This study is the most comprehensive analysis of the \ncharacteristics of women with an endometriosis diagnosis in England to date.  \nHow this study might affect research, practice or policy \nThis research provides important information to gynaecologists, clinicians and other allied health \nprofessionals, as well as policy makers, to illustrate the prevalence of endometriosis and the groups \nmost affected by endometriosis and barriers to receiving a diagnosis. In the Women’s Health Strategy \nfor England, menstrual health and gynaecological conditions were identified as one of the priority \nareas, with a call for evidence and investment in women’s health research. \n \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 4 \n \nIntroduction \nEndometriosis is a chronic disease and the second most common gynaecological condition in the UK, \nestimated to impact approximately 1.5 million women (1). Endometriosis is a condition where \nendometrial tissue, similar to the lining of the uterus, grows in other places, such as the ovaries and \nfallopian tubes. Common symptoms include chronic pelvic pain, fatigue, heavy menstrual bleeding, \npain during or after sex, painful urination and bowel movements, and reduced fertility (2,3). \nSymptoms can vary across women, and severity of symptoms often does not reflect the severity of \nthe condition (4). Endometriosis usually affects women during their reproductive years (between \nmenarche and menopause) but can affect women of any age (5). While the exact cause of \nendometriosis is unknown, several factors have been implicated in its development, including \nimmune, endocrine, genetic, and environmental influences (3,6). \nDespite the profound impacts endometriosis poses on women’s lives, there has been no population \nstudy in England assessing the characteristics of women living with endometriosis. Given the disease \nis known to have negative impacts across many domains, such as psychological, social, and \neconomic, understanding which groups of women are most affected is imperative to further quantify \ndifferences in the progression and burden of this disease, and inform targeted work to reduce these \ninequalities. This has ramifications clinically, for understanding which groups are most affected, as \nwell as from a policy perspective to provide evidence-based change to targeted populations.  \nThe diagnosis of endometriosis can be challenging due to the non-specific nature of its symptoms, \nthe overlap of symptoms with other conditions such as pelvic inflammatory disease or irritable bowel \nsyndrome, and the lack of a definitive non-invasive diagnostic test. In England, it takes on average \neight years from onset of symptoms to receiving a diagnosis (7). The gold standard for diagnosis is \nlaparoscopic visualisation and biopsy of the lesions (8). In the current study, we utilise individual \npopulation level data from Hospital Episode Statistics (HES) (9) data for England to define a cohort of \nwomen who have received a diagnosis of endometriosis in a National Health Service (NHS) hospital \nover a ten-year period. Using Census 2011 data we estimate differences by sociodemographic \ncharacteristics including ethnic group, socioeconomic position, education level, country of birth, \nhealth, disability and region. This is of important public health significance due to the prevalence of \nthis condition, its debilitating symptoms, and the broader socioeconomic burden of this disease. \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 5 \n \nMethods \nStudy design and data sources \nWe conducted a population level retrospective cohort study using the Public Health Data Asset 2011 \nCohort (10), which combines Census 2011 data, death registrations, and 2009-2021 Hospital Episode \nStatistics (HES) Admitted Patient Care (APC) data (11). Census 2011 has been linked to the 2011–\n2013 NHS Patient Registers to obtain NHS numbers, with a linkage rate of 94.6% (10). The decennial \nCensus for England and Wales captured population and household characteristics of 56 million \npeople in 2011 with respondents reporting detailed demographic information. HES is a curated data \nset capturing records of patients attending accident and emergency units, admitted for treatment or \nattending outpatient clinics at NHS hospitals in England. Each HES record includes up to 20 diagnosis \nvalues, with the first value (primary diagnosis) recording the main condition being treated or \ninvestigated, and the other values recording any relevant secondary/subsidiary diagnoses (12). \nStudy population \nThe study population includes all women enumerated in the 2011 Census who were usual residents \nin England on Census Day (27 March 2011) and could be linked to an NHS number [Supplementary \nTable 3]. We defined two cohorts of women with endometriosis. For our main analysis, we estimated \nprevalence by identifying women with any endometriosis diagnosis (primary or secondary) during \nthe study period between 27 March 2011 and 31 December 2021 and a control group of women \nenumerated in Census 2011 with no evidence of endometriosis during the study period. For our \nsupplementary analysis, we estimated incidence by identifying a group of women with a primary \nendometriosis diagnosis only during our study period and used two years of HES data (1 April 2009 \nto 26 March 2011) prior to the study start to exclude instances where the diagnosis during the study \nperiod was not the first. The control group of women for the supplementary analysis had no \ndiagnosis of endometriosis during the study period, or in the two years prior . All groups were filtered \nto restrict our cohort to people who self-reported as female in the 2011 Census [Supplementary \nTable 3]. \nOutcome \nDiagnosis of endometriosis was defined from the Admitted Patient Care (APC) data using \nInternational Classification of Diseases, Tenth Revision (ICD-10) codes N80.0-N80.9 [Supplementary \nTable 1]. For our main analysis, an outcome was identified if a diagnosis was recorded as a primary or \nsecondary diagnosis, and for the supplementary analysis an outcome was identified only if \nendometriosis was the primary diagnosis. The episode must have started and ended within our study \nperiod for an outcome to be identified. Outcomes were coded as binary. \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 6 \n \nCovariates  \nAll sociodemographic variables included in the analyses were self-reported in the 2011 Census. \nExposures included were age on Census Day (five-year age bands), ethnic group (detailed and \naggregated), country of birth, main language, Index of Multiple Deprivation (IMD) decile, National \nStatistics Socioeconomic Classification (NS-SEC) of the Household Reference Person (HRP), highest \nlevel of educational qualification, general health, disability, rural/urban, region and upper tier local \nauthority (UTLA). Groupings of all exposures can be seen in Supplementary Table 4. Where Census \ndata was missing or not applicable, a “Not classified” group was included (13). \nAn indicator of health was determined using number of HES APC admissions in the two years prior (1 \nApril 2009 to 26 March 2011) to our study start date for any reason, excluding mentions of \nendometriosis. Number of HES APC admissions were grouped into 0 episodes, 1 to 3 episodes, 4 to 6 \nepisodes, 7 to 9 episodes, 10 to 14 episodes, and 15 or more episodes. We did not include self-\nreported health or self-reported disability status from 2011 Census as health adjustments in the \nmodels, as these variables could capture effects from symptoms related to endometriosis.  \nIn our descriptive analysis, we investigated age at endometriosis diagnosis and method of hospital \nadmission. Age at endometriosis diagnosis refers to age at first diagnosis during the study period and \nwas obtained from HES data, but if missing or zero (0.01%) in the administrative data it was \ncalculated using the date difference between the date of birth self-reported in 2011 Census and the \nhospital episode start date. Method of hospital admission (emergency or non-emergency) was \nsourced from the HES APC data. Emergency admissions are defined in HES as “unpredictable and at \nshort notice because of clinical need” (12), and were classified according to the codes listed in \nSupplementary Table 2. \nStatistical Analysis \nTo describe the prevalence of endometriosis, we report crude and age-standardised rates of \ndiagnosis per 100,000 people. Age-standardised rates were calculated as the weighted average of \nage-specific rates in five-year age bands. The age-specific weights represent the overall age \ndistribution in the observed study population. To identify characteristics associated with \nendometriosis diagnosis, we used logistic regression models to estimate the odds ratios of being \ndiagnosed with endometriosis at least once during the study period across different exposure \ngroups. Models were first adjusted for age and secondly for age and health (number of pre-study HES \nAPC admissions, excluding mentions of endometriosis). Age was included as a natural spline with \nboundary knots at the 1st and 99th percentile and five interior knots. The number of knots was \nchosen using the lowest Akaike information criterion (AIC). General health is a confounder between \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 7 \n \nsocioeconomic factors and endometriosis; hence we’ve adjusted our models to ensure the \nrelationship between our characteristics of interest and endometriosis are not explained by \ndifferences in general health. When looking at general health and disability as exposures, we only \nadjusted for age. Additionally, for ethnic group, we fitted models also adjusted for main language and \ncountry of birth independently and together. For region, we also adjusted for socioeconomic status \nusing IMD decile and highest level of qualification as a proxy. All counts are rounded to the nearest 5 \nand counts of less than 10 suppressed for disclosure reasons. \nAll analyses were conducted in R version 4.4 and Python version 3.10. \nSensitivity tests \nAll demographic information was measured at the time of Census 2011. Some characteristics may \nchange over time, which could introduce a bias in our estimates. We ran sensitivity analyses using \njust two years of follow-up (27 March 2011 to 31 December 2013) to assess the robustness of our \nfindings across the 10-year period. In addition, we also ran sensitivity analyses when education was \nthe exposure using only women aged 25 years and older on Census Day, as education is more likely \nto be stable after this age. \nEthics and Data Availability \nWe obtained ethical approval for this work from the National Statistics Data Ethics Advisory \nCommittee (NSDEC23(18)). All data relating to this work has been published as an ONS dataset. All \ncode is available in a GitHub repository. \nPublic and Patient Involvement \nWomen with endometriosis have reviewed this manuscript and provided feedback prior to \nsubmission. \n \n \n \n \n \n \n \n \n \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 8 \n \nResults  \nMain results \nTo estimate prevalence of endometriosis diagnosis, we analysed endometriosis diagnoses recorded \nas either primary or secondary diagnoses in HES APC. 24,560,795 women were included in our main \nanalysis, of which 262,065 had a diagnosis of endometriosis. This is equivalent to approximately 2% \nof women aged 15 to 49 years on Census Day [Table 1, Figure 1]. Crude rates of endometriosis \ndiagnosis per 100,000 people were highest among women aged 30-34 (2,307.61) and 35-39 \n(2,492.44) years at the time of Census [Table 2]. The average age at time of diagnosis was 38.9 years \n(IQR: 30-47 years) [Supplementary Table 16]. \nLooking at the number of admissions in our cohort over time, which is the first time a woman has a \nrecorded primary or secondary endometriosis diagnosis in our main analysis, and the first time a \nwoman has a recorded primary endometriosis diagnosis in our supplementary analysis, we see that \nthe monthly count has been relatively consistent since 2011, except with a marked reduction during \nthe early coronavirus pandemic of 2020 [Supplementary Table 5]. The most frequent primary \ndiagnosis type by ICD-10 code in our main cohort was endometriosis (n = 116,835, 44.6%), with the \nnext most prevalent being leiomyoma of uterus (n = 21,845, 8.3%). The top ten primary diagnosis \ncodes included a range of other gynaecological presentations such as abdominal and pelvic pain, \nnon-inflammatory disorders of ovary, fallopian tube and broad ligament, as well as excessive \nfrequent and irregular menstruation [Supplementary Table 6]. 18.7% of admissions were \nemergencies, with the majority (81.3%) being classified as non-emergency presentations \n[Supplementary Table 17]. \nAge-standardised rates of endometriosis were highest in the White (1,099.91 per 100,000 persons; \n95% confidence interval (CI):1,095.39-1,104.43) and Mixed/Multiple (1,115.95 per 100,000 persons; \n95%CI:1,081.00-1,150.90) ethnic groups [Table 2]. These two groups showed similar odds of \ndiagnosis in both the age-adjusted model (Odds Ratio (OR) for Mixed/Multiple compared to White: \n0.98; 95%CI:0.95-1.00) and the age- and health-adjusted model (OR:0.98; 95%CI:0.95-1.00) [Table 4]. \nCompared to the White ethnic group, the largest differences in odds of diagnosis were observed for \nthe Other ethnic group (OR:0.75; 95%CI:0.72-0.79), the Asian/Asian British group (OR:0.78; \n95%CI:0.77-0.79) and the Black/African/Caribbean/Black British (OR:0.80; 95%CI:0.78-0.82) ethnic \ngroups. However, when adjusting for country of birth and main language, the odds of diagnosis for \nthe Other ethnic group (OR:0.95; 95%CI:0.91-1.00) were no longer significantly different from the \nWhite ethnic group.  \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 9 \n \nUsing the more granular breakdown for ethnic group, compared to the White British (White \nEnglish/Welsh/Scottish/Northern Irish/British) group, the Chinese (Asian/Asian British) (OR:0.46; \n95%CI:0.43-0.48) and Arab (Other ethnic group) (OR:0.52; 95%CI:0.48-0.57) ethnic groups had the \nlowest odds of diagnosis in the age- and health-adjusted model. Compared to the White British \ngroup, the odds of diagnosis were significantly lower for the Black African (OR:0.61; 95%CI:0.59-0.64) \nand Other Black (OR:0.88; 95%CI:0.82-0.93) groups, but not for the Black Caribbean (OR:1.03; \n95%CI:0.99-1.06) group. When adjusting for country of birth and main language, the odds ratios for \nthe Black African (OR:0.69; 95%CI:0.67-0.72) and Other Black (OR:0.94; 95%CI:0.88-1.00) groups \nmoved closer to the null, though the odds for the Black African group remained significantly lower \nthan the White British group. In contrast, the odds for the Black Caribbean (OR:1.05; 95%CI:1.02-\n1.09) group were significantly higher than for the White British group. \nOdds of diagnosis were lower for women born outside the UK (compared to those born in the UK; \nOR:0.72; 95%CI:0.71-0.73), and for women whose main language was not English (compared to \nthose with English as their first language; OR:0.67; 95%CI:0.66-0.68) [Table 5].  \nAnalysis of socioeconomic factors, such as IMD, showed the odds were lowest for women living in \nthe most deprived and least deprived areas of the country [Table 5].  Analysis of household NS-SEC \nshowed the odds were lowest for women in households with the highest and lowest socio-economic \nclassifications. When looking at education level, the odds ratios were lowest for women with Other \n(foreign or vocational) qualifications (OR:0.87; 95%CI:0.85-0.89) or no qualifications (OR:0.96; \n95%CI:0.94-0.97), compared with Level 4 and above qualifications (e.g., degree level). \nOdds of diagnosis were highest for women self-reporting to be in bad health (OR:2.04; 95%CI:2.00-\n2.09) or fair health (OR:1.92; 95%CI:1.90-1.94), compared with those in very good health. Disabled \nwomen reporting to be limited a little (OR:1.58; 95%CI:1.55-1.60) or limited a lot (OR:1.38; \n95%CI:1.36-1.40) in their day-to-day activities had significantly higher odds of diagnosis, compared \nwith non-disabled women. \nCompared to London, the odds of a diagnosis were higher for all other regions of the UK (although \nthe 95% CI included the null for the North East (OR:1.02;95%CI:1.00-1.05)) [Supplementary Table 9]. \nAdjusting for IMD and education level had minimal impact on these results overall, except for \nYorkshire and the Humber where the 95% CI included the null after adjustment (OR:1.02;95%CI:1.00-\n1.03). Broadly, we did not see clear differences in age-standardised rates of diagnoses by UTLA \n[Figure 3]. \nSupplementary results \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 10 \n \nTo estimate incidence of endometriosis diagnosis, we restricted our analysis to endometriosis \ndiagnoses recorded as primary diagnoses in HES APC. A total of 24,382,270 women were included in \nour supplementary analysis, with 120,515 having a primary diagnosis of endometriosis \n[Supplementary Table 3]. The crude rates of endometriosis diagnosis per 100,000 people were \nhighest among women aged 25-29 (1,217.48) and 30-34 (1,210.61) years at the time of Census [Table \n2]. The average age at diagnosis was 35 years (IQR: 27-43 years), five years younger than in the main \nanalysis [Supplementary Table 16]. 10.7% of the admissions in this group were classified as \nemergencies [Supplementary Table 17].Using the aggregated ethnicity breakdown, the odds ratio \ncomparing diagnosis in the Black/African/Caribbean/Black British ethnic group to the White group \nwas lower in the supplementary analysis (OR:0.67; 95%CI :0.65-0.70) compared to the main analysis \n(OR:0.91; 95%CI:0.89-0.93) in the fully adjusted model [Table 4]. Furthermore, the odds ratios \nbetween women self-reporting to be in very good health and those in good, fair, bad or very bad \nhealth were lower compared to the main analysis [Table 5]. Similarly, the odds ratios of women self-\nreporting to be limited a little or a lot in their day-to-day activities compared to those not limited \nwere lower in the supplementary analysis. When looking at region, the odds ratios were generally \nsimilar, though Yorkshire and the Humber and the South East showed the most prominent increases \nin odds ratios compared to the main analysis [Supplementary Table 9]. In general, for all other \nsociodemographic characteristics we saw the same pattern of results as in the main analysis [Tables \n3-5, Supplementary Table 10]. \nSensitivity results \nTo assess the robustness of our findings over a 10-year follow-up, we repeated the analysis using just \na two-year follow-up. 71,345 women had received an endometriosis diagnosis in our main sensitivity \nanalysis and 32,855 women had received a primary endometriosis diagnosis in our supplementary \nsensitivity analysis [Supplementary Table 3]. For both groups, the sensitivity results were consistent \nwith the findings from the 10-year follow-up. The odds ratios for women reporting to be in good, fair, \nbad or very bad health compared to those in very good health were all further from the null in the \ntwo-year follow up compared to the 10-year follow up [Table 5 and Supplementary Table 13]. \nSimilarly, the odds ratios for women reporting to be limited a little or a lot in their day-to-day \nactivities compared to those not limited were higher in the two-year follow up. Furthermore, we \nrepeated our analysis of the highest level of educational qualification exposure restricting to women \naged 25 years and over on Census Day, since education level is more stable from this age onwards. \nResults followed a similar pattern to the analysis of women of any age [Table 5 and Supplementary \nTable 13]. \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 11 \n \nDiscussion \nIn this large, population-based cohort spanning a decade, we estimated the prevalence of \nendometriosis to be 2% of reproductive age women in England (14). Our results show that the odds \nratios of receiving an endometriosis diagnosis vary significantly by sociodemographic characteristics \nin England and reflect differences in both the likelihood of having an endometriosis diagnosis by \nsociodemographic characteristic as well as the likelihood of receiving a diagnosis in an NHS hospital. \nPrevious estimates of prevalence range from 2% to 10% in the general female population and up to \n50% in women with infertility (15). Endometriosis UK and the World Health Organization (WHO) \nestimate that 1 in 10 women of reproductive age have endometriosis (1,16), and pooled estimates  \nof European studies suggest a prevalence rate of 1.4% in the general population (17). Our prevalence \nestimate of 2% of reproductive age women is lower than some previous studies. However, our \nestimate reflects the number of women who have been diagnosed with endometriosis in an NHS \nhospital in England between 2011 and 2021. Additionally, our analysis only includes women whose \nCensus 2011 response could be linked to an NHS number; it does not capture all women who have \nhad a diagnosis in hospital. For our main analysis, our sample includes approximately 85% of all \nwomen who received an endometriosis diagnosis in hospital during this period [Supplementary Table \n3]. It is important to note that prevalence of endometriosis diagnoses does not reflect the true \nprevalence of endometriosis, as not all women will have a diagnosis. In the US, for instance, six out \nof ten cases go undiagnosed (18). \nThe average age at first endometriosis diagnosis, where endometriosis was the primary diagnosis, \nwas 35 years. Given that symptoms of this disease can start in puberty, these findings support \nprevious work suggesting that women are facing barriers and delays in receiving an endometriosis \ndiagnosis (7). In an Australian cohort study of over 10,000 women, 1 in 9 self-reported suspected or \nconfirmed endometriosis by age 44, with most being diagnosed during their early thirties (19). Since \n2020, NHS gynaecology waiting lists in England have grown faster than any other elective speciality \nin percentage terms (20). If left untreated, endometriosis may progress and further negatively \nimpact on quality of life. Future work should explore inequalities in delays in diagnosis across \nsociodemographic groups.  \nFinding significantly lower odds of being diagnosed with endometriosis for Chinese, Arab or Black \nAfrican ethnic groups compared to the White English/Welsh/Scottish/Northern Irish/British group is \nbroadly consistent with existing literature from elsewhere in the world, and smaller UK-based studies \n(21). Many of these findings need to be interpreted with caution due to limited quality literature \nexploring this topic and selection bias of White women in research studies. Historically, \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 12 \n \nendometriosis has been thought to be a disease most prevalent in White women (18), but our results \ndemonstrate the odds of diagnosis are as high in the Mixed and Black Caribbean groups. Differences \nin prevalence between ethnic groups are likely to be explained by social and structural issues around \naccess to healthcare and systemic racism (21).  \nIt is important to highlight that the increase in the number of new first diagnoses from mid-2020 \nonwards is likely a consequence of increases in post-pandemic admissions for other causes. When \nlooking at primary diagnoses of endometriosis only, as per the supplementary analysis, the number \nof new monthly cases does not show this trend; the number of monthly cases recovers to the pre-\npandemic level and remains consistent [Supplementary Table 5].  \nPrevious survey data has shown that over half of women who had symptoms of endometriosis, \nwithout a confirmed diagnosis, attended A&E at least once due to their symptoms (22). Although a \nsmall proportion of our cases were identified as emergency admissions (10.7%) [Supplementary \nTable 17], it is still an important finding that warrants additional exploration. The cost of repeated \npresentations at A&E centres, as well as emergency treatment costs, in contrast to elective care, \nshould be considered when making recommendations for diagnostic care for women with \nendometriosis (23). \nOur sensitivity analyses, using two years of follow-up, showed similar findings to the 10-year follow \nup. One difference was the odds for women reporting to be limited in their day-to-day activities, \ncompared to those not limited, were higher in the two-year follow up. These findings indicate that \nsymptoms of endometriosis could be contributing to self-reported health and disability status, \nhighlighting how debilitating endometriosis symptoms can be on overall health. \nA strength of our study is the use of population level data for England, making it the most \ncomprehensive study into the characteristics of women with endometriosis in England to date. \nFurthermore, the linkage to Census data provides detailed information on socioeconomic \ncharacteristics. A key limitation of our work is we only capture women who have an endometriosis \ndiagnosis in an NHS hospital in England which, according to the National Institute for Health and Care \nExcellence (NICE) guidelines, will capture women who have been referred to gynaecology if initial \nsymptom management in primary care is not effective (8). A laparoscopy should be used to diagnose \nendometriosis even if an ultrasound or MRI has come back normal. Subsequent research should \nexplore diagnosis of endometriosis using primary care data, in addition to secondary care data, to get \na more complete understanding of the burden of disease, as well as capturing symptoms related to \ndiagnosis since many women remain undiagnosed. \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 13 \n \nIn our study, women living in the most deprived and least deprived areas had lower odds of \ndiagnosis, compared to those living in other areas. This might be explained by those living in the \nmost deprived areas facing barriers to seeking treatment (24) including longer NHS waiting times \n(25), and those living in the least deprived areas being more likely to use private healthcare (26). \nFollowing a similar trend, we found lower odds of diagnosis for women in households with the \nhighest and lowest socio-economic classifications. Of all educational groups, women in the Other \nqualifications group had the lowest odds of diagnosis. This group includes women with foreign \nqualifications, and therefore may include women who received an endometriosis diagnosis outside \nEngland not captured by the HES data. \nClinically, endometriosis is typically classified into four stages, from minimal to severe, taking into \naccount location and depth of disease in relation to other pelvic structures (27). We are limited to \nassessing endometriosis diagnosis as a binary outcome based on our data but implore researchers to \nevaluate sociodemographic characteristics associated with disease severity in subsequent work. \nImportantly, treatment and hospital diagnosis are based on severity of symptoms, not clinical stage, \nwhich often does not correspond to severity of symptoms and cannot be determined without \nlaparoscopy. Finally, using regional information on place of residence from Census (i.e., at the start of \nthe study period) and HES (i.e., at time of diagnosis) is limited as we are not able to evaluate regional \ndifferences in diagnosis or procedures. Across the UK, there are 79 specialist endometriosis centres \naccredited by the British Society of Gynaecology and Endoscopy (28), and subsequent work should \nlook at differences here.  \nTo conclude, our study provides the first systematic assessment of the characteristics of women \ndiagnosed with endometriosis in England. We utilised a decade’s worth of endometriosis diagnoses \ntaking place in NHS hospitals and linked to Census data to provide a granular understanding of the \ngroups who have the highest odds of receiving an endometriosis diagnosis. This work provides \nimportant information to gynaecologists, clinicians and other allied health professionals, as well as \npolicy makers to illustrate the prevalence of endometriosis and the groups most affected.  \nContributions of authors \nILW, VN and DA conceptualised and designed the study. ILW, EC and HB prepared the study data. HB \nperformed the statistical analysis, which was quality checked by ILW. All authors contributed to \ninterpretation of the findings. ILW and HB wrote the original draft. All authors contributed to review \nand editing of the manuscript and approved the final manuscript. ILW is the guarantor . The \ncorresponding author attests that all listed authors meet authorship criteria and that no others \nmeeting the criteria have been omitted. \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 14 \n \nAcknowledgements  \nWe would like to thank Endometriosis UK and DHSC for supporting our research and public \nengagement. We would also like to thank Emily Williams for supporting with a literature review early \nin the study development. \nFunding \nThis study received funding from His Majesties Treasury’s Labour Market Evaluation Fund (29). GCS is \nsupported by the Medical Research Council (MR/Z504634). \nConflicts of interest \nThe authors have no conflicts to declare. \n \nReferences \n1. Endometriosis UK. Endometriosis Facts and Figures [Internet]. [cited 2024 Dec 9]. Available \nfrom: https://www.endometriosis-uk.org/endometriosis-facts-and-figures \n2. National Health Service (NHS). Endometriosis [Internet]. 2024 [cited 2024 Dec 9]. Available \nfrom: https://www.nhs.uk/conditions/endometriosis/ \n3. Zondervan KT, Becker CM, Koga K, Missmer SA, Taylor RN, Viganò P. Endometriosis. Nat Rev \nDis Prim. 2018 Jul 19;4(1):9.  \n4. Endometriosis UK. Understanding Endometriosis - Information Pack [Internet]. 2012 Mar \n[cited 2024 Dec 9]. Available from: https://www.endometriosis-\nuk.org/sites/default/files/2022-07/Understanding-endometriosis- pack_0.pdf \n5. Royal College of Nursing. What is Endometriosis? [Internet]. 2024 Nov [cited 2024 Dec 9]. \nAvailable from: https://www.rcn.org.uk/Professional-Development/publications/rcn-what-is-\nendometriosis-uk-pub-011-851 \n6. Zhang H, Sheng S, Pan Z, Zhao L, Yang C, Li C, et al. Immune and endocrine regulation in \nendometriosis: what we know. J Endometr Uterine Disord. 2023 Dec;4:100049.  \n7. All-Party Parliamentary Group (APPG) on Endometriosis. Endometriosis in the UK: time for \nchange [Internet]. 2020 [cited 2024 Dec 9]. Available from: https://www.endometriosis-\nuk.org/sites/default/files/files/Endometriosis APPG Report Oct 2020.pdf \n8. National Institute for Health and Care Excellence (NICE). Endometriosis: diagnosis and \nmanagement [Internet]. 2017 [cited 2024 Dec 9]. Available from: \nhttps://www.nice.org.uk/guidance/ng73?UID=3550395512024113061359 \n9. NHS Digital. Hospital Episode Statistics (HES) [Internet]. 2024 [cited 2024 Dec 9]. Available \nfrom: https://digital.nhs.uk/data-and-information/data-tools-and-services/data-\nservices/hospital-episode-statistics \n10. Nafilyan V, Bosworth M, Morgan J, Ayoubkhani D, Dolby T, Groom P, et al. Cohort Profile: The \nPublic Health Data Asset, 2011 cohort. Int J Epidemiol. 2024 Feb 1;53(1).  \n11. Herbert A, Wijlaars L, Zylbersztejn A, Cromwell D, Hardelid P. Data Resource Profile: Hospital \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 15 \n \nEpisode Statistics Admitted Patient Care (HES APC). Int J Epidemiol. 2017 Aug 1;46(4):1093-\n1093i.  \n12. NHS Digital. Hospital Episode Statistics Data Dictionary [Internet]. 2024 [cited 2024 Dec 9]. \nAvailable from: https://digital.nhs.uk/data-and-information/data-tools-and-services/data-\nservices/hospital-episode-statistics/hospital-episode-statistics-data-dictionary \n13. Office for National Statistics (ONS). Quality and methods [Internet]. [cited 2024 Dec 11]. \nAvailable from: \nhttps://www.ons.gov.uk/census/2011census/2011censusdata/2011censususerguide/qualitya\nndmethods \n14. World Health Organization (WHO). Women of reproductive age (15-49 years) population \n(thousands) [Internet]. [cited 2024 Dec 9]. Available from: \nhttps://platform.who.int/data/maternal-newborn-child-adolescent-ageing/indicator-\nexplorer-new/mca/women-of-reproductive-age-(15-49-years)-population-(thousands) \n15. Becker CM, Bokor A, Heikinheimo O, Horne A, Jansen F, Kiesel L, et al. ESHRE guideline: \nendometriosis. Hum Reprod Open. 2022 Mar 4;2022(2).  \n16. World Health Organization (WHO). Endometriosis [Internet]. 2023 [cited 2024 Dec 10]. \nAvailable from: https://www.who.int/news-room/fact-sheets/detail/endometriosis \n17. Parazzini F, Roncella E, Cipriani S, Trojano G, Barbera V, Herranz B, et al. The frequency of \nendometriosis in the general and selected populations: A systematic review. J Endometr \nPelvic Pain Disord. 2020 Sep 2;12(3–4):176–89.  \n18. Westwood S, Fannin M, Ali F, Thigpen J, Tatro R, Hernandez A, et al. Disparities in Women \nWith Endometriosis Regarding Access to Care, Diagnosis, Treatment, and Management in the \nUnited States: A Scoping Review. Cureus. 2023 May 9;  \n19. Rowlands I, Abbott J, Montgomery G, Hockey R, Rogers P, Mishra G. Prevalence and incidence \nof endometriosis in Australian women: a data linkage cohort study. BJOG An Int J Obstet \nGynaecol. 2021 Mar;128(4):657–65.  \n20. Royal College of Obstetricians and Gynaecologists (RCOG), Lane Clark & Peacock (LCP) Health \nAnalytics. Elective Recovery Tracker [Internet]. Available from: \nhttps://rcogwaitinglist.health.lcp.com/gynaecology \n21. Bougie O, Nwosu I, Warshafsky C. Revisiting the impact of race/ethnicity in endometriosis. \nReprod Fertil. 2022 Apr 1;3(2):R34–41.  \n22. Endometriosis UK. “Dismissed, ignored and belittled” The long road to endometriosis \ndiagnosis in the UK [Internet]. 2024 Mar [cited 2024 Dec 9]. Available from: \nhttps://www.endometriosis-uk.org/diagnosis-report \n23. Simoens S, Dunselman G, Dirksen C, Hummelshoj L, Bokor A, Brandes I, et al. The burden of \nendometriosis: costs and quality of life of women with endometriosis and treated in referral \ncentres. Hum Reprod. 2012 May 1;27(5):1292–9.  \n24. The King’s Fund. Illustrating the relationship between poverty and NHS services [Internet]. \n2024 [cited 2024 Dec 10]. Available from: https://www.kingsfund.org.uk/insight-and-\nanalysis/long-reads/relationship-poverty-nhs-services \n25. O’Dowd A. Poverty status is linked to worse quality of care. BMJ. 2020 Jan 23;m303.  \n26. Devaja A. Health inequalities: the unintended consequences of private healthcare policy? Bull \nR Coll Surg Engl. 2023 Sep;105(6):272–3.  \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nPage | 16 \n \n27. American Society for Reproductive Medicine. Revised American Society for Reproductive \nMedicine classification of endometriosis: 1996. Fertil Steril. 1997 May;67(5):817–21.  \n28. British Society for Gynaecological Endoscopy (BSGE). All accredited endometriosis centres \n[Internet]. [cited 2024 Dec 9]. Available from: \nhttps://www.bsge.org.uk/centre/category/accredited-centres/ \n29. HM Treasury. £12.4 million to help change choices about work [Internet]. 2023 [cited 2024 \nDec 9]. Available from: https://www.gov.uk/government/news/124-million-to-help-change-\nchoices-about-work \n \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nFigures and Tables \n \nFigure 1: Age distribution of study population at time of first endometriosis diagnosis in study period  \n \nThe number of diagnoses at each year of age for first endometriosis diagnosis in hospital in our main analysis population (blue) and supplementary \nanalysis population (teal). The main population includes any endometriosis diagnosis and the supplementary includes primary diagnoses only. The \nvertical bar marks the mean age at time of diagnosis for each cohort. \n \n \n \n \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\n \nFigure 2: Odds of receiving an endometriosis diagnosis by sociodemographic characteristics \n \nThe odds ratio of receiving an endometriosis diagnosis \nby ethic group, main language, IMD decile group, \nhighest level of qualification and disability. The bold \nvertical line indicates an odds ratio of 1. Point estimates \nare presented with 95% confidence intervals. All \nmodels account for age and health (except for the \ndisability model, which is only age-adjusted).  \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nFigure 3: Age-standardised rates of endometriosis diagnosis per 100,000 people by upper tier local authority (UTLA) \nAge-standardised rates of endometriosis diagnosis per 100,000 people shown by UTLA, with darker colours illustrating higher rates. The regions in \nGreater London have been shown in a second pop-out. \n \n \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nTable 1: Characteristics of the study population \nCategory Subcategory \nMain analysis Supplementary analysis \nCount (%), with an \nendometriosis \ndiagnosis \nCount (%), no \nendometriosis \ndiagnosis \nCount (%), with an \nendometriosis \ndiagnosis \nCount (%), no \nendometriosis \ndiagnosis \nTotal Total 262,065 (100.00%) 24,298,730 (100.00%) 120,515 (100.00%) 24,261,755 (100.00%) \nAge on Census \nDay (five-year \nbands) \n0 to 9 years 1,410 (0.54%) 2,708,135 (11.15%) 815 (0.68%) 2,708,130 (11.16%) \n10 to 14 years 9,320 (3.56%) 1,347,480 (5.55%) 6,335 (5.26%) 1,347,470 (5.55%) \n15 to 19 years 21,035 (8.03%) 1,407,965 (5.79%) 14,085 (11.69%) 1,407,710 (5.80%) \n20 to 24 years 29,090 (11.10%) 1,459,880 (6.01%) 17,515 (14.53%) 1,458,270 (6.01%) \n25 to 29 years 34,780 (13.27%) 1,563,890 (6.44%) 19,235 (15.96%) 1,560,665 (6.43%) \n30 to 34 years 36,525 (13.94%) 1,546,200 (6.36%) 18,890 (15.67%) 1,541,400 (6.35%) \n35 to 39 years 40,835 (15.58%) 1,597,595 (6.57%) 19,280 (16.00%) 1,591,170 (6.56%) \n40 to 44 years 38,780 (14.80%) 1,788,375 (7.36%) 14,740 (12.23%) 1,780,960 (7.34%) \n45 to 49 years 23,420 (8.94%) 1,815,010 (7.47%) 6,365 (5.28%) 1,808,275 (7.45%) \n50 to 54 years 10,020 (3.82%) 1,606,830 (6.61%) 1,645 (1.36%) 1,603,825 (6.61%) \n55 to 59 years 5,705 (2.18%) 1,432,900 (5.90%) 595 (0.49%) 1,431,685 (5.90%) \n60 to 64 years 4,720 (1.80%) 1,532,995 (6.31%) 440 (0.37%) 1,532,125 (6.31%) \n65 to 69 years 3,140 (1.20%) 1,222,205 (5.03%) 255 (0.21%) 1,221,590 (5.04%) \n70 to 74 years 1,815 (0.69%) 1,013,275 (4.17%) 170 (0.14%) 1,012,880 (4.17%) \n75 to 79 years 930 (0.35%) 853,440 (3.51%) 70 (0.06%) 853,200 (3.52%) \n80 years and over 540 (0.21%) 1,402,560 (5.77%) 80 (0.07%) 1,402,390 (5.78%) \nEthnic group \n(detailed) \nWhite: English/Welsh/Scottish/Northern Irish/British 214,790 (81.96%) 19,797,270 (81.47%) 98,835 (82.00%) 19,766,680 (81.47%) \nWhite: Irish 1,870 (0.71%) 239,835 (0.99%) 750 (0.62%) 239,530 (0.99%) \nWhite: Gypsy or Irish Traveller 285 (0.11%) 22,510 (0.09%) 145 (0.12%) 22,480 (0.09%) \nMixed/multiple: Other White 10,970 (4.19%) 1,058,285 (4.36%) 5,510 (4.57%) 1,056,710 (4.36%) \nMixed/multiple: White and Black Caribbean 2,075 (0.79%) 165,525 (0.68%) 1,010 (0.84%) 165,340 (0.68%) \nMixed/multiple: White and Black African 575 (0.22%) 62,745 (0.26%) 265 (0.22%) 62,680 (0.26%) \nMixed/multiple: White and Asian 1,250 (0.48%) 131,930 (0.54%) 650 (0.54%) 131,800 (0.54%) \nMixed/multiple: Other Mixed 1,340 (0.51%) 114,005 (0.47%) 665 (0.55%) 113,860 (0.47%) \nAsian: Indian 6,435 (2.46%) 610,470 (2.51%) 2,910 (2.41%) 609,540 (2.51%) \nAsian: Pakistani 5,050 (1.93%) 478,250 (1.97%) 2,370 (1.97%) 477,670 (1.97%) \nAsian: Bangladeshi 2,130 (0.81%) 184,775 (0.76%) 1,115 (0.93%) 184,585 (0.76%) \nAsian: Chinese 1,020 (0.39%) 150,135 (0.62%) 460 (0.38%) 149,940 (0.62%) \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nAsian: Other Asian 4,125 (1.57%) 338,575 (1.39%) 1,985 (1.65%) 337,950 (1.39%) \nBlack: African 3,725 (1.42%) 404,305 (1.66%) 1,315 (1.09%) 403,775 (1.66%) \nBlack: Caribbean 3,570 (1.36%) 271,760 (1.12%) 1,305 (1.08%) 271,235 (1.12%) \nBlack: Other Black 1,010 (0.39%) 90,670 (0.37%) 365 (0.30%) 90,560 (0.37%) \nOther: Arab 480 (0.18%) 65,715 (0.27%) 215 (0.18%) 65,640 (0.27%) \nOther: Any other ethnic group 1,370 (0.52%) 111,975 (0.46%) 655 (0.54%) 111,775 (0.46%) \nEthnic group \n(aggregated) \nWhite 227,915 (86.97%) 21,117,900 (86.91%) 105,235 (87.32%) 21,085,400 (86.91%) \nMixed/Multiple ethnic groups 5,240 (2.00%) 474,205 (1.95%) 2,590 (2.15%) 473,680 (1.95%) \nAsian/Asian British 18,760 (7.16%) 1,762,200 (7.25%) 8,835 (7.33%) 1,759,690 (7.25%) \nBlack/African/Caribbean/Black British 8,305 (3.17%) 766,740 (3.16%) 2,980 (2.47%) 765,570 (3.16%) \nOther ethnic group 1,850 (0.71%) 177,685 (0.73%) 870 (0.72%) 177,415 (0.73%) \nCountry of \nbirth \nBorn in the UK 228,185 (87.07%) 21,138,305 (86.99%) 105,285 (87.36%) 21,106,510 (86.99%) \nBorn outside the UK 33,880 (12.93%) 3,160,425 (13.01%) 15,230 (12.64%) 3,155,245 (13.01%) \nMain \nlanguage \nMain language is English 243,775 (93.02%) 22,515,935 (92.66%) 111,750 (92.73%) 22,481,585 (92.66%) \nMain language is not English 18,295 (6.98%) 1,782,795 (7.34%) 8,765 (7.27%) 1,780,170 (7.34%) \nIMD decile \ngroup \n1 (most deprived) 26,840 (10.24%) 2,320,860 (9.55%) 12,410 (10.30%) 2,317,520 (9.55%) \n2 28,175 (10.75%) 2,372,300 (9.76%) 13,110 (10.88%) 2,368,680 (9.76%) \n3 28,185 (10.75%) 2,400,785 (9.88%) 13,000 (10.79%) 2,397,215 (9.88%) \n4 27,705 (10.57%) 2,418,465 (9.95%) 12,950 (10.75%) 2,414,655 (9.95%) \n5 26,905 (10.27%) 2,440,470 (10.04%) 12,325 (10.23%) 2,436,690 (10.04%) \n6 26,495 (10.11%) 2,470,245 (10.17%) 12,160 (10.09%) 2,466,405 (10.17%) \n7 25,705 (9.81%) 2,448,335 (10.08%) 11,630 (9.65%) 2,444,385 (10.08%) \n8 25,290 (9.65%) 2,468,450 (10.16%) 11,595 (9.62%) 2,464,685 (10.16%) \n9 24,510 (9.35%) 2,473,380 (10.18%) 11,195 (9.29%) 2,469,625 (10.18%) \n10 (least deprived) 22,255 (8.49%) 2,485,440 (10.23%) 10,135 (8.41%) 2,481,890 (10.23%) \nHousehold \nNS-SEC \nClass 1: Higher managerial, administrative and \nprofessional occupations \n32,185 (12.28%) 3,176,175 (13.07%) 14,305 (11.87%) 3,171,170 (13.07%) \nClass 2: Lower managerial, administrative and \nprofessional occupations \n64,460 (24.60%) 5,551,555 (22.85%) 29,420 (24.41%) 5,541,925 (22.84%) \nClass 3: Intermediate occupations 31,575 (12.05%) 2,810,730 (11.57%) 14,480 (12.02%) 2,806,250 (11.57%) \nClass 4: Small employers and own account workers 31,405 (11.98%) 2,878,815 (11.85%) 14,555 (12.08%) 2,874,320 (11.85%) \nClass 5: Lower supervisory and technical occupations 23,075 (8.81%) 1,955,050 (8.05%) 10,850 (9.00%) 1,951,825 (8.04%) \nClass 6: Semi-routine occupations 35,325 (13.48%) 3,285,515 (13.52%) 16,130 (13.38%) 3,280,765 (13.52%) \nClass 7: Routine occupations 28,225 (10.77%) 2,850,570 (11.73%) 12,905 (10.71%) 2,846,665 (11.73%) \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nClass 8: Never worked and long-term unemployed 9,415 (3.59%) 1,023,645 (4.21%) 4,310 (3.58%) 1,022,655 (4.22%) \nStudents 4,880 (1.86%) 384,530 (1.58%) 2,705 (2.24%) 384,130 (1.58%) \nNot classified 1,520 (0.58%) 382,150 (1.57%) 850 (0.71%) 382,045 (1.57%) \nHighest level \nof \nqualification \nNo academic or professional qualifications 27,445 (10.47%) 4,987,950 (20.53%) 9,805 (8.14%) 4,983,360 (20.54%) \nLevel 1 41,690 (15.91%) 2,747,050 (11.31%) 18,565 (15.40%) 2,740,815 (11.30%) \nLevel 2 52,270 (19.95%) 3,332,820 (13.72%) 24,960 (20.71%) 3,325,775 (13.71%) \nApprenticeship 2,495 (0.95%) 194,095 (0.80%) 1,230 (1.02%) 193,780 (0.80%) \nLevel 3 41,200 (15.72%) 2,326,415 (9.57%) 20,575 (17.07%) 2,321,240 (9.57%) \nLevel 4 and above 73,295 (27.97%) 5,346,080 (22.00%) 31,835 (26.42%) 5,333,930 (21.98%) \nOther qualifications 9,455 (3.61%) 1,024,225 (4.22%) 4,055 (3.36%) 1,022,785 (4.22%) \nNot classified 14,215 (5.42%) 4,340,090 (17.86%) 9,490 (7.87%) 4,340,070 (17.89%) \nHighest level \nof \nqualification, \n25 years and \nover \nNo academic or professional qualifications 23,490 (9.0%) 4,739,170 (19.5%) 7,375 (6.1%) 4,734,710 (19.5%) \nLevel 1 33,115 (12.6%) 2,323,345 (9.6%) 13,300 (11.0%) 2,317,400 (9.6%) \nLevel 2 38,330 (14.6%) 2,600,945 (10.7%) 15,985 (13.3%) 2,594,395 (10.7%) \nApprenticeship 1,485 (0.6%) 149,715 (0.6%) 565 (0.5%) 149,450 (0.6%) \nLevel 3 29,300 (11.2%) 1,644,790 (6.8%) 13,005 (10.8%) 1,640,105 (6.8%) \nLevel 4 and above 66,830 (25.5%) 4,967,190 (20.4%) 27,975 (23.2%) 4,955,400 (20.4%) \nOther qualifications 8,660 (3.3%) 950,115 (3.9%) 3,555 (3.0%) 948,715 (3.9%) \nAged 0 to 24 years on Census Day 60,855 (23.2%) 6,923,460 (28.5%) 38,750 (32.2%) 6,921,585 (28.5%) \nGeneral \nhealth \nVery good health 106,960 (40.81%) 10,991,240 (45.23%) 55,080 (45.70%) 10,979,385 (45.25%) \nGood health 108,825 (41.53%) 8,454,135 (34.79%) 49,080 (40.73%) 8,437,570 (34.78%) \nFair health 33,660 (12.84%) 3,447,010 (14.19%) 12,365 (10.26%) 3,440,875 (14.18%) \nBad health 10,260 (3.91%) 1,096,775 (4.51%) 3,350 (2.78%) 1,094,830 (4.51%) \nVery bad health 2,365 (0.90%) 309,565 (1.27%) 640 (0.53%) 309,095 (1.27%) \nDisability Day-to-day activities not limited 224,445 (85.64%) 19,621,265 (80.75%) 107,530 (89.23%) 19,591,160 (80.75%) \nDay-to-day activities limited a little 23,345 (8.91%) 2,477,375 (10.20%) 8,570 (7.11%) 2,473,210 (10.19%) \nDay-to-day activities limited a lot 14,275 (5.45%) 2,200,090 (9.05%) 4,415 (3.66%) 2,197,385 (9.06%) \nRural/urban \nclassification \nUrban 221,370 (84.47%) 19,900,870 (81.90%) 102,360 (84.94%) 19,870,420 (81.90%) \nRural 40,695 (15.53%) 4,397,860 (18.10%) 18,155 (15.06%) 4,391,335 (18.10%) \nRegion North East 11,745 (4.48%) 1,213,585 (4.99%) 5,195 (4.31%) 1,211,880 (5.00%) \nNorth West 38,070 (14.53%) 3,246,810 (13.36%) 16,800 (13.94%) 3,241,575 (13.36%) \nYorkshire and the Humber 23,920 (9.13%) 2,426,160 (9.98%) 11,515 (9.55%) 2,422,780 (9.99%) \nEast Midlands 24,225 (9.24%) 2,106,400 (8.67%) 10,470 (8.69%) 2,102,550 (8.67%) \nWest Midlands 28,325 (10.81%) 2,567,255 (10.57%) 12,675 (10.52%) 2,563,435 (10.57%) \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nEast of England 27,225 (10.39%) 2,725,220 (11.22%) 12,325 (10.23%) 2,721,420 (11.22%) \nLondon 37,900 (14.46%) 3,516,895 (14.47%) 17,010 (14.11%) 3,512,015 (14.48%) \nSouth East 43,715 (16.68%) 4,012,685 (16.51%) 22,015 (18.27%) 4,006,705 (16.51%) \nSouth West 26,945 (10.28%) 2,483,720 (10.22%) 12,510 (10.38%) 2,479,385 (10.22%) \nNote: For household NS-SEC, “Not classified” includes those not living in a private household in Census 2011, occupations not stated or inadequately \ndescribed, or not classifiable for other reasons. For highest level of qualification, “Not classified” includes those aged under 16 in Census 2011. \n \nTable 2: Age-standardised rates of endometriosis diagnosis per 100,000 people \nCategory  Subcategory Main analysis,  \nAge-standardised rate [95% CI] \nSupplementary analysis, \n Age-standardised rate [95% CI] \nTotal Total 1,067.01 [1,062.92, 1,071.09] 494.27 [491.48, 497.06] \nAge on Census Day \n(five-year bands)* \n0 to 9 years 52.04 [49.32, 54.75] 30.01 [27.95, 32.07] \n10 to 14 years 686.76 [672.82, 700.71] 468.09 [456.56, 479.61] \n15 to 19 years 1,472.01 [1,452.12, 1,491.90] 990.79 [974.43, 1,007.15] \n20 to 24 years 1,953.77 [1,931.31, 1,976.22] 1,186.83 [1,169.25, 1,204.40] \n25 to 29 years 2,175.44 [2,152.57, 2,198.30] 1,217.48 [1,200.28, 1,234.69] \n30 to 34 years 2,307.61 [2,283.94, 2,331.27] 1,210.61 [1,193.34, 1,227.87] \n35 to 39 years 2,492.44 [2,468.27, 2,516.62] 1,197.24 [1,180.34, 1,214.14] \n40 to 44 years 2,122.37 [2,101.25, 2,143.50] 820.74 [807.49, 833.99] \n45 to 49 years 1,273.91 [1,257.60, 1,290.23] 350.81 [342.20, 359.43] \n50 to 54 years 619.79 [607.65, 631.92] 102.52 [97.57, 107.48] \n55 to 59 years 396.50 [386.21, 406.78] 41.47 [38.14, 44.81] \n60 to 64 years 306.88 [298.13, 315.64] 28.64 [25.97, 31.32] \n65 to 69 years 256.34 [247.37, 265.30] 20.79 [18.23, 23.34] \n70 to 74 years 179.00 [170.77, 187.23] 16.88 [14.35, 19.41] \n75 to 79 years 108.97 [101.97, 115.97] 8.09 [6.29, 10.23] \n80 years and over 38.63 [35.38, 41.88] 5.70 [4.52, 7.10] \nEthnic group (detailed) White: English/Welsh/Scottish/Northern Irish/British 1,133.38 [1,128.57, 1,138.19] 535.50 [532.16, 538.85] \nWhite: Irish 893.36 [849.91, 936.82] 399.39 [368.73, 430.04] \nWhite: Gypsy or Irish Traveller 1,131.79 [997.11, 1,266.48] 544.29 [452.56, 636.02] \nWhite: Other White 735.99 [720.11, 751.87] 338.37 [328.20, 348.53] \nMixed/multiple: White and Black Caribbean 1,226.87 [1,162.53, 1,291.20] 496.15 [461.75, 530.55] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nMixed/multiple: White and Black African 960.14 [869.97, 1,050.31] 401.92 [344.65, 459.19] \nMixed/multiple: White and Asian 1,056.28 [989.37, 1,123.19] 489.97 [448.59, 531.35] \nMixed/multiple: Other Mixed 1,103.76 [1,038.51, 1,169.01] 489.66 [450.45, 528.87] \nAsian: Indian 866.00 [843.97, 888.02] 373.43 [359.40, 387.46] \nAsian: Pakistani 953.87 [924.32, 983.43] 394.66 [377.58, 411.74] \nAsian: Bangladeshi 968.79 [918.98, 1,018.60] 466.77 [432.59, 500.94] \nAsian: Chinese 552.82 [516.53, 589.11] 226.36 [204.68, 248.05] \nAsian: Other Asian 906.58 [876.81, 936.35] 414.89 [395.83, 433.95] \nBlack: African 737.11 [708.64, 765.58] 248.30 [230.76, 265.84] \nBlack: Caribbean 1,160.08 [1,121.26, 1,198.90] 446.65 [422.15, 471.14] \nBlack: Other Black 1,035.64 [966.75, 1,104.52] 361.98 [323.51, 400.45] \nOther: Arab 640.74 [577.32, 704.16] 254.49 [217.39, 291.59] \nOther: Any other ethnic group 988.75 [933.23, 1,044.27] 455.95 [419.64, 492.26] \nEthnic group \n(aggregated) \nWhite 1,099.91 [1,095.39, 1,104.43] 518.66 [515.53, 521.80] \nMixed/Multiple ethnic groups 1,115.95 [1,081.00, 1,150.90] 480.88 [460.51, 501.24] \nAsian/Asian British 879.76 [866.33, 893.18] 385.29 [376.90, 393.68] \nBlack/African/Caribbean/Black British 901.28 [881.12, 921.44] 317.09 [305.52, 328.66] \nOther ethnic group 870.48 [827.61, 913.35] 385.69 [358.55, 412.83] \nCountry of birth Born in the UK 1,123.29 [1,118.67, 1,127.91] 524.36 [521.19, 527.54] \nBorn outside the UK 795.89 [786.88, 804.90] 346.14 [340.24, 352.05] \nMain language Main language is English 1,105.20 [1,100.80, 1,109.59] 513.66 [510.64, 516.67] \nMain language is not English 738.05 [726.25, 749.86] 324.65 [317.24, 332.07] \nIMD decile group 1 (most deprived) 1,091.42 [1,078.24, 1,104.61] 487.16 [478.52, 495.80] \n2 1,103.68 [1,090.69, 1,116.67] 499.36 [490.77, 507.96] \n3 1,091.64 [1,078.81, 1,104.47] 493.28 [484.75, 501.80] \n4 1,093.81 [1,080.89, 1,106.73] 507.11 [498.35, 515.87] \n5 1,081.39 [1,068.46, 1,094.32] 498.32 [489.52, 507.13] \n6 1,069.64 [1,056.75, 1,082.52] 498.67 [489.80, 507.54] \n7 1,074.34 [1,061.17, 1,087.50] 500.10 [491.00, 509.21] \n8 1,059.20 [1,046.09, 1,072.31] 501.59 [492.42, 510.75] \n9 1,040.15 [1,027.00, 1,053.29] 493.76 [484.53, 502.98] \n10 (least deprived) 972.65 [959.53, 985.76] 465.28 [455.99, 474.57] \nHousehold NS-SEC Class 1: Higher managerial, administrative and professional occupations 924.09 [913.67, 934.51] 418.32 [411.23, 425.41] \nClass 2: Lower managerial, administrative and professional occupations 1,077.35 [1,068.96, 1,085.74] 500.73 [494.95, 506.51] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nClass 3: Intermediate occupations 1,176.47 [1,163.44, 1,189.50] 554.51 [545.45, 563.58] \nClass 4: Small employers and own account workers 1,087.29 [1,075.18, 1,099.40] 515.04 [506.61, 523.46] \nClass 5: Lower supervisory and technical occupations 1,165.92 [1,150.86, 1,180.98] 550.46 [540.09, 560.83] \nClass 6: Semi-routine occupations 1,149.28 [1,137.23, 1,161.34] 532.12 [523.86, 540.37] \nClass 7: Routine occupations 1,097.03 [1,084.15, 1,109.90] 510.60 [501.76, 519.45] \nClass 8: Never worked and long-term unemployed 943.12 [923.60, 962.63] 409.14 [396.71, 421.56] \nStudents 956.71 [911.46, 1,001.95] 422.31 [400.15, 444.46] \nNot classified 557.61 [509.49, 605.73] 229.89 [201.42, 258.35] \nHighest level of \nqualification \nNo academic or professional qualifications 925.87 [913.88, 937.86] 407.31 [398.99, 415.63] \nLevel 1 1,141.74 [1,130.40, 1,153.07] 528.62 [520.81, 536.43] \nLevel 2 1,153.47 [1,143.35, 1,163.59] 538.38 [531.53, 545.23] \nApprenticeship 1,174.24 [1,121.95, 1,226.53] 569.15 [532.40, 605.90] \nLevel 3 1,110.28 [1,098.64, 1,121.92] 512.43 [505.04, 519.81] \nLevel 4 and above 962.71 [949.23, 976.19] 430.45 [419.87, 441.03] \nOther qualifications 809.37 [791.52, 827.22] 352.08 [339.90, 364.26] \nNot classified 114.09 [111.61, 116.57] 76.92 [74.88, 78.97] \nHighest level of \nqualification, 25 years \nand over \nNo academic or professional qualifications 737.51 [727.07, 747.94] 291.51 [284.60, 298.42] \nLevel 1 902.17 [892.05, 912.29] 381.04 [374.34, 387.74] \nLevel 2 918.69 [909.41, 927.98] 388.65 [382.59, 394.70] \nApprenticeship 909.52 [859.85, 959.20] 393.45 [359.22, 427.69] \nLevel 3 913.54 [902.49, 924.59] 385.20 [378.43, 391.97] \nLevel 4 and above 756.44 [750.56, 762.33] 299.22 [295.67, 302.78] \nOther qualifications 691.53 [676.66, 706.39] 277.49 [268.20, 286.79] \nAged 0 to 24 years on Census Day 247.77 [245.80, 249.74] 158.94 [157.35, 160.52] \nGeneral health Very good health 856.74 [851.29, 862.19] 408.92 [405.41, 412.43] \nGood health 1,202.81 [1,195.53, 1,210.09] 568.78 [563.64, 573.92] \nFair health 1,665.43 [1,645.16, 1,685.69] 736.43 [722.07, 750.80] \nBad health 1,899.49 [1,853.46, 1,945.52] 772.06 [740.71, 803.41] \nVery bad health 1,609.22 [1,528.88, 1,689.55] 564.92 [513.08, 616.76] \nDisability Day-to-day activities not limited 1,021.89 [1,017.62, 1,026.15] 479.88 [477.00, 482.75] \nDay-to-day activities limited a little 1,694.95 [1,670.71, 1,719.19] 750.27 [733.18, 767.35] \nDay-to-day activities limited a lot 1,458.87 [1,430.50, 1,487.23] 573.82 [554.74, 592.89] \nRural/urban \nclassification \nUrban 1,071.48 [1,067.01, 1,075.95] 493.54 [490.52, 496.57] \nRural 1,054.93 [1,044.37, 1,065.49] 504.37 [496.84, 511.89] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nRegion North East 986.62 [968.74, 1,004.49] 444.00 [431.91, 456.10] \nNorth West 1,173.24 [1,161.45, 1,185.03] 523.71 [515.78, 531.63] \nYorkshire and the Humber 987.58 [975.05, 1,000.11] 477.90 [469.16, 486.64] \nEast Midlands 1,156.18 [1,141.60, 1,170.76] 508.23 [498.48, 517.98] \nWest Midlands 1,112.52 [1,099.55, 1,125.48] 502.16 [493.41, 510.90] \nEast of England 1,019.01 [1,006.89, 1,031.13] 469.55 [461.25, 477.85] \nLondon 938.91 [929.26, 948.56] 409.09 [402.84, 415.34] \nSouth East 1,106.97 [1,096.58, 1,117.36] 565.89 [558.40, 573.38] \nSouth West 1,147.74 [1,134.00, 1,161.49] 548.28 [538.65, 557.91] \n* Age on Census Day (five-year bands) shows the crude rates per 100,000 people. All other categories show the age-standardised rates per 100,000 people. \nNote: For household NS-SEC, “Not classified” includes those not living in a private household in Census 2011, occupations not stated or inadequately \ndescribed, or not classifiable for other reasons. For highest level of qualification, “Not classified” includes those aged under 16 in Census 2011. \n \nTable 3: Odds ratios for endometriosis diagnosis and 95% confidence intervals by age on Census Day (five-year bands)  \nAnalysis type Term Adjusted for health,  \nOR [95% CI] \nMain analysis 0 to 9 years 0.02 [0.02, 0.02] \n10 to 14 years 0.31 [0.30, 0.31] \n15 to 19 years 0.64 [0.63, 0.65] \n20 to 24 years 0.79 [0.78, 0.80] \n25 to 29 years 0.86 [0.85, 0.87] \n30 to 34 years 0.90 [0.88, 0.91] \n40 to 44 years 0.88 [0.87, 0.89] \n45 to 49 years 0.53 [0.52, 0.54] \n50 to 54 years 0.25 [0.25, 0.26] \n55 to 59 years 0.16 [0.16, 0.16] \n60 to 64 years 0.12 [0.12, 0.13] \n65 to 69 years 0.10 [0.10, 0.10] \n70 to 74 years 0.07 [0.06, 0.07] \n75 to 79 years 0.04 [0.04, 0.04] \n80 years and over 0.01 [0.01, 0.01] \nSupplementary analysis 0 to 9 years 0.02 [0.02, 0.03] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\n10 to 14 years 0.44 [0.42, 0.45] \n15 to 19 years 0.89 [0.87, 0.91] \n20 to 24 years 1.01 [0.99, 1.03] \n25 to 29 years 1.00 [0.98, 1.02] \n30 to 34 years 0.98 [0.96, 1.00] \n40 to 44 years 0.71 [0.69, 0.72] \n45 to 49 years 0.30 [0.29, 0.31] \n50 to 54 years 0.09 [0.08, 0.09] \n55 to 59 years 0.04 [0.03, 0.04] \n60 to 64 years 0.02 [0.02, 0.03] \n65 to 69 years 0.02 [0.01, 0.02] \n70 to 74 years 0.01 [0.01, 0.02] \n75 to 79 years 0.01 [0.00, 0.01] \n80 years and over 0.00 [0.00, 0.01] \nNote: Reference category: 35 to 39 years \n \nTable 4: Odds ratios for endometriosis diagnosis and 95% confidence intervals by ethnic group  \nAnalysis type Exposure Term Adjusted for age,  \nOR [95% CI] \nAdjusted for age \nand health,  \nOR [95% CI] \nAdjusted for age, \nhealth and \ncountry of birth,  \nOR [95% CI] \nAdjusted for age, \nhealth and main \nlanguage,  \nOR [95% CI] \nAdjusted for age, \nhealth, country \nof birth and \nmain language,  \nOR [95% CI] \nMain analysis Ethnic group \n(detailed) \n(Reference \ncategory: White: \nEnglish/Welsh/Sc\nottish/Northern \nIrish/British) \nWhite: Irish 0.81 [0.77, 0.85] 0.82 [0.79, 0.86] 0.88 [0.84, 0.93] 0.82 [0.79, 0.86] 0.86 [0.82, 0.90] \nWhite: Gypsy or Irish \nTraveller \n0.99 [0.88, 1.11] 0.94 [0.84, 1.06] 0.95 [0.85, 1.07] 0.95 [0.85, 1.07] 0.96 [0.85, 1.08] \nWhite: Other White 0.63 [0.62, 0.64] 0.66 [0.64, 0.67] 0.74 [0.72, 0.76] 0.74 [0.73, 0.76] 0.78 [0.76, 0.81] \nMixed/multiple: White \nand Black Caribbean \n1.05 [1.00, 1.09] 1.02 [0.98, 1.07] 1.03 [0.99, 1.08] 1.03 [0.98, 1.07] 1.03 [0.99, 1.08] \nMixed/multiple: White \nand Black African \n0.84 [0.77, 0.91] 0.84 [0.77, 0.91] 0.89 [0.82, 0.97] 0.87 [0.80, 0.95] 0.90 [0.83, 0.98] \nMixed/multiple: White \nand Asian \n0.87 [0.82, 0.92] 0.88 [0.84, 0.93] 0.91 [0.86, 0.96] 0.90 [0.85, 0.95] 0.91 [0.86, 0.97] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nMixed/multiple: Other \nMixed \n0.94 [0.89, 1.00] 0.96 [0.91, 1.01] 1.00 [0.95, 1.06] 0.99 [0.94, 1.04] 1.01 [0.96, 1.07] \nAsian: Indian 0.75 [0.73, 0.77] 0.77 [0.75, 0.79] 0.82 [0.80, 0.84] 0.82 [0.80, 0.84] 0.84 [0.82, 0.87] \nAsian: Pakistani 0.78 [0.76, 0.80] 0.76 [0.74, 0.78] 0.81 [0.78, 0.83] 0.82 [0.79, 0.84] 0.84 [0.82, 0.87] \nAsian: Bangladeshi 0.84 [0.80, 0.87] 0.83 [0.79, 0.86] 0.90 [0.86, 0.94] 0.92 [0.88, 0.97] 0.95 [0.91, 1.00] \nAsian: Chinese 0.43 [0.40, 0.45] 0.46 [0.43, 0.48] 0.50 [0.47, 0.54] 0.50 [0.47, 0.54] 0.53 [0.50, 0.56] \nAsian: Other Asian 0.81 [0.78, 0.83] 0.83 [0.80, 0.86] 0.92 [0.89, 0.96] 0.93 [0.90, 0.96] 0.98 [0.94, 1.01] \nBlack: African 0.62 [0.60, 0.65] 0.61 [0.59, 0.64] 0.68 [0.66, 0.71] 0.65 [0.63, 0.68] 0.69 [0.67, 0.72] \nBlack: Caribbean 1.04 [1.01, 1.08] 1.03 [0.99, 1.06] 1.07 [1.03, 1.10] 1.03 [1.00, 1.07] 1.05 [1.02, 1.09] \nBlack: Other Black 0.89 [0.84, 0.95] 0.88 [0.82, 0.93] 0.92 [0.87, 0.98] 0.92 [0.86, 0.98] 0.94 [0.88, 1.00] \nOther: Arab 0.53 [0.48, 0.58] 0.52 [0.48, 0.57] 0.58 [0.53, 0.63] 0.59 [0.54, 0.64] 0.62 [0.56, 0.68] \nOther: Any other ethnic \ngroup \n0.85 [0.81, 0.90] 0.85 [0.81, 0.90] 0.94 [0.89, 0.99] 0.94 [0.89, 1.00] 0.98 [0.93, 1.04] \nEthnic group \n(aggregated) \n(Reference \ncategory: White) \nMixed/Multiple ethnic \ngroups \n0.98 [0.95, 1.00] 0.98 [0.95, 1.00] 1.02 [0.99, 1.05] 0.99 [0.97, 1.02] 1.01 [0.99, 1.04] \nAsian/Asian British 0.77 [0.76, 0.78] 0.78 [0.77, 0.79] 0.90 [0.89, 0.92] 0.89 [0.87, 0.90] 0.93 [0.91, 0.95] \nBlack/African/Caribbean/B\nlack British \n0.81 [0.80, 0.83] 0.80 [0.78, 0.82] 0.92 [0.90, 0.95] 0.84 [0.82, 0.86] 0.91 [0.89, 0.93] \nOther ethnic group 0.76 [0.72, 0.79] 0.75 [0.72, 0.79] 0.91 [0.87, 0.96] 0.90 [0.86, 0.94] 0.95 [0.91, 1.00] \nSupplementary \nanalysis \nEthnic group \n(detailed) \n(Reference \ncategory: White: \nEnglish/Welsh/Sc\nottish/Northern \nIrish/British) \nWhite: Irish 0.77 [0.72, 0.83] 0.79 [0.74, 0.85] 0.84 [0.78, 0.90] 0.79 [0.74, 0.85] 0.82 [0.76, 0.89] \nWhite: Gypsy or Irish \nTraveller \n0.98 [0.83, 1.16] 0.93 [0.79, 1.10] 0.94 [0.80, 1.11] 0.95 [0.80, 1.12] 0.95 [0.81, 1.12] \nWhite: Other White 0.63 [0.61, 0.65] 0.66 [0.64, 0.68] 0.73 [0.70, 0.75] 0.73 [0.70, 0.75] 0.76 [0.73, 0.79] \nMixed/multiple: White \nand Black Caribbean \n0.93 [0.88, 0.99] 0.92 [0.86, 0.97] 0.92 [0.86, 0.98] 0.92 [0.86, 0.98] 0.92 [0.86, 0.98] \nMixed/multiple: White \nand Black African \n0.73 [0.65, 0.83] 0.73 [0.65, 0.83] 0.77 [0.68, 0.87] 0.76 [0.67, 0.85] 0.78 [0.69, 0.88] \nMixed/multiple: White \nand Asian \n0.85 [0.78, 0.91] 0.86 [0.80, 0.93] 0.88 [0.82, 0.95] 0.88 [0.81, 0.95] 0.89 [0.82, 0.96] \nMixed/multiple: Other \nMixed \n0.90 [0.83, 0.97] 0.91 [0.84, 0.98] 0.95 [0.88, 1.02] 0.93 [0.86, 1.01] 0.95 [0.88, 1.03] \nAsian: Indian 0.69 [0.67, 0.72] 0.71 [0.69, 0.74] 0.75 [0.72, 0.78] 0.74 [0.72, 0.77] 0.76 [0.73, 0.79] \nAsian: Pakistani 0.70 [0.67, 0.73] 0.69 [0.66, 0.72] 0.72 [0.69, 0.75] 0.73 [0.70, 0.76] 0.74 [0.71, 0.77] \nAsian: Bangladeshi 0.82 [0.78, 0.87] 0.82 [0.77, 0.87] 0.87 [0.82, 0.92] 0.89 [0.83, 0.94] 0.91 [0.85, 0.96] \nAsian: Chinese 0.38 [0.34, 0.41] 0.40 [0.37, 0.44] 0.44 [0.40, 0.48] 0.44 [0.40, 0.48] 0.45 [0.41, 0.50] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nAsian: Other Asian 0.79 [0.76, 0.83] 0.82 [0.78, 0.85] 0.89 [0.85, 0.94] 0.89 [0.85, 0.94] 0.93 [0.88, 0.98] \nBlack: African 0.44 [0.42, 0.46] 0.43 [0.41, 0.46] 0.47 [0.45, 0.50] 0.45 [0.43, 0.48] 0.48 [0.45, 0.50] \nBlack: Caribbean 0.83 [0.79, 0.88] 0.83 [0.78, 0.87] 0.85 [0.80, 0.90] 0.83 [0.78, 0.88] 0.84 [0.80, 0.89] \nBlack: Other Black 0.65 [0.59, 0.72] 0.64 [0.58, 0.71] 0.67 [0.60, 0.74] 0.67 [0.60, 0.74] 0.68 [0.61, 0.75] \nOther: Arab 0.46 [0.40, 0.52] 0.45 [0.40, 0.52] 0.49 [0.43, 0.56] 0.50 [0.43, 0.57] 0.52 [0.45, 0.59] \nOther: Any other ethnic \ngroup \n0.83 [0.77, 0.89] 0.83 [0.77, 0.90] 0.90 [0.83, 0.97] 0.90 [0.83, 0.98] 0.93 [0.86, 1.01] \nEthnic group \n(aggregated) \n(Reference \ncategory: White) \nMixed/Multiple ethnic \ngroups \n0.90 [0.87, 0.94] 0.90 [0.87, 0.94] 0.94 [0.90, 0.97] 0.92 [0.88, 0.95] 0.93 [0.90, 0.97] \nAsian/Asian British 0.72 [0.71, 0.74] 0.73 [0.72, 0.75] 0.83 [0.82, 0.85] 0.82 [0.80, 0.84] 0.85 [0.83, 0.87] \nBlack/African/Caribbean/B\nlack British \n0.60 [0.58, 0.62] 0.59 [0.57, 0.62] 0.68 [0.66, 0.71] 0.62 [0.60, 0.65] 0.67 [0.65, 0.70] \nOther ethnic group 0.71 [0.67, 0.76] 0.71 [0.67, 0.76] 0.85 [0.80, 0.91] 0.84 [0.78, 0.90] 0.88 [0.82, 0.94] \n \nTable 5: Odds ratios for endometriosis diagnosis and 95% confidence intervals by country of birth, main language, IMD decile group, \nhousehold NS-SEC, highest level of qualification, general health, disability and rural/urban classification \nAnalysis type Exposure Term Adjusted for age,  \nOR [95% CI] \nAdjusted for age and health,  \nOR [95% CI] \nMain analysis Country of birth (Reference \ncategory: Born in the UK) \nBorn outside the UK 0.70 [0.70, 0.71] 0.72 [0.71, 0.73] \nMain language (Reference \ncategory: Main language is English) \nMain language is not English 0.66 [0.65, 0.67] 0.67 [0.66, 0.68] \nIMD decile group (Reference \ncategory: 10 (least deprived)) \n1 (most deprived) 1.14 [1.12, 1.16] 1.07 [1.05, 1.09] \n2 1.15 [1.13, 1.17] 1.10 [1.08, 1.12] \n3 1.13 [1.11, 1.15] 1.10 [1.08, 1.12] \n4 1.13 [1.11, 1.15] 1.11 [1.09, 1.13] \n5 1.12 [1.10, 1.14] 1.11 [1.09, 1.13] \n6 1.11 [1.09, 1.13] 1.10 [1.08, 1.12] \n7 1.12 [1.10, 1.14] 1.11 [1.09, 1.13] \n8 1.10 [1.08, 1.12] 1.09 [1.07, 1.11] \n9 1.08 [1.06, 1.10] 1.07 [1.05, 1.09] \nHousehold NS-SEC (Reference \ncategory: Class 1: Higher \nClass 2: Lower managerial, administrative and \nprofessional occupations \n1.18 [1.16, 1.19] 1.17 [1.15, 1.19] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nmanagerial, administrative and \nprofessional occupations) \nClass 3: Intermediate occupations 1.29 [1.27, 1.31] 1.27 [1.25, 1.29] \nClass 4: Small employers and own account \nworkers \n1.19 [1.17, 1.21] 1.17 [1.15, 1.19] \nClass 5: Lower supervisory and technical \noccupations \n1.28 [1.25, 1.30] 1.24 [1.22, 1.26] \nClass 6: Semi-routine occupations 1.26 [1.24, 1.27] 1.21 [1.19, 1.23] \nClass 7: Routine occupations 1.20 [1.18, 1.22] 1.15 [1.13, 1.17] \nClass 8: Never worked and long-term \nunemployed \n1.03 [1.01, 1.06] 0.96 [0.93, 0.98] \nStudents 0.88 [0.86, 0.91] 0.90 [0.87, 0.93] \nNot classified 0.56 [0.53, 0.59] 0.57 [0.54, 0.60] \nHighest level of qualification \n(Reference category: Level 4 and \nabove) \nNo academic or professional qualifications 1.02 [1.01, 1.04] 0.96 [0.94, 0.97] \nLevel 1 1.24 [1.22, 1.25] 1.18 [1.17, 1.20] \nLevel 2 1.25 [1.24, 1.27] 1.22 [1.20, 1.23] \nApprenticeship 1.32 [1.27, 1.38] 1.27 [1.22, 1.32] \nLevel 3 1.18 [1.17, 1.20] 1.17 [1.16, 1.18] \nOther qualifications 0.88 [0.86, 0.90] 0.87 [0.85, 0.89] \nNot classified 1.53 [1.48, 1.58] 1.50 [1.45, 1.55] \nHighest level of qualification, 25 \nyears and over (Reference \ncategory: Level 4 and above) \nNo academic or professional qualifications 1.00 [0.99, 1.02] 0.96 [0.94, 0.97] \nLevel 1 1.20 [1.19, 1.22] 1.17 [1.16, 1.19] \nLevel 2 1.23 [1.21, 1.25] 1.21 [1.19, 1.22] \nApprenticeship 1.24 [1.17, 1.30] 1.21 [1.15, 1.28] \nLevel 3 1.23 [1.22, 1.25] 1.22 [1.20, 1.23] \nOther qualifications 0.91 [0.89, 0.93] 0.90 [0.88, 0.92] \nGeneral health (Reference \ncategory: Very good health) \nGood health 1.43 [1.42, 1.45] x \nFair health 1.92 [1.90, 1.94] x \nBad health 2.04 [2.00, 2.09] x \nVery bad health 1.79 [1.71, 1.86] x \nDisability (Reference category: Day-\nto-day activities not limited) \nDay-to-day activities limited a little 1.58 [1.55, 1.60] x \nDay-to-day activities limited a lot 1.38 [1.36, 1.40] x \nRural/urban classification \n(Reference category: Urban) \nRural 0.98 [0.97, 0.99] 0.98 [0.97, 0.99] \nSupplementary \nanalysis \nCountry of birth (Reference \ncategory: Born in the UK) \nBorn outside the UK 0.67 [0.66, 0.68] 0.68 [0.67, 0.69] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nMain language (Reference \ncategory: Main language is English) \nMain language is not English 0.64 [0.63, 0.66] 0.66 [0.64, 0.67] \nIMD decile group (Reference \ncategory: 10 (least deprived)) \n1 (most deprived) 1.06 [1.03, 1.08] 1.00 [0.97, 1.03] \n2 1.08 [1.05, 1.11] 1.04 [1.02, 1.07] \n3 1.06 [1.04, 1.09] 1.04 [1.01, 1.07] \n4 1.09 [1.07, 1.12] 1.08 [1.05, 1.10] \n5 1.08 [1.05, 1.11] 1.06 [1.04, 1.09] \n6 1.08 [1.05, 1.11] 1.07 [1.04, 1.10] \n7 1.08 [1.05, 1.11] 1.07 [1.04, 1.10] \n8 1.09 [1.06, 1.12] 1.08 [1.05, 1.11] \n9 1.07 [1.04, 1.10] 1.06 [1.04, 1.09] \nHousehold NS-SEC (Reference \ncategory: Class 1: Higher \nmanagerial, administrative and \nprofessional occupations) \nClass 2: Lower managerial, administrative and \nprofessional occupations \n1.20 [1.18, 1.23] 1.20 [1.17, 1.22] \nClass 3: Intermediate occupations 1.33 [1.30, 1.36] 1.31 [1.28, 1.34] \nClass 4: Small employers and own account \nworkers \n1.23 [1.20, 1.26] 1.21 [1.18, 1.24] \nClass 5: Lower supervisory and technical \noccupations \n1.32 [1.29, 1.35] 1.28 [1.25, 1.32] \nClass 6: Semi-routine occupations 1.27 [1.25, 1.30] 1.23 [1.20, 1.26] \nClass 7: Routine occupations 1.22 [1.19, 1.25] 1.18 [1.15, 1.21] \nClass 8: Never worked and long-term \nunemployed \n0.98 [0.95, 1.01] 0.91 [0.88, 0.94] \nStudents 0.88 [0.84, 0.91] 0.90 [0.86, 0.93] \nNot classified 0.55 [0.51, 0.59] 0.56 [0.53, 0.61] \nHighest level of qualification \n(Reference category: Level 4 and \nabove) \nNo academic or professional qualifications 1.03 [1.00, 1.05] 0.95 [0.93, 0.98] \nLevel 1 1.31 [1.29, 1.34] 1.25 [1.23, 1.27] \nLevel 2 1.34 [1.31, 1.36] 1.29 [1.27, 1.31] \nApprenticeship 1.47 [1.39, 1.56] 1.40 [1.32, 1.48] \nLevel 3 1.24 [1.21, 1.26] 1.22 [1.20, 1.24] \nOther qualifications 0.89 [0.86, 0.92] 0.87 [0.85, 0.90] \nNot classified 1.64 [1.57, 1.71] 1.59 [1.53, 1.66] \nHighest level of qualification, 25 \nyears and over (Reference \ncategory: Level 4 and above) \nNo academic or professional qualifications 0.99 [0.97, 1.02] 0.95 [0.92, 0.97] \nLevel 1 1.28 [1.26, 1.31] 1.25 [1.22, 1.28] \nLevel 2 1.31 [1.29, 1.34] 1.28 [1.26, 1.31] \nApprenticeship 1.35 [1.24, 1.47] 1.32 [1.21, 1.43] \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint \n\nLevel 3 1.31 [1.28, 1.33] 1.29 [1.26, 1.31] \nOther qualifications 0.92 [0.89, 0.96] 0.92 [0.88, 0.95] \nGeneral health (Reference \ncategory: Very good health) \nGood health 1.40 [1.38, 1.42] x \nFair health 1.79 [1.76, 1.83] x \nBad health 1.84 [1.77, 1.90] x \nVery bad health 1.35 [1.24, 1.46] x \nDisability (Reference category: Day-\nto-day activities not limited) \nDay-to-day activities limited a little 1.53 [1.50, 1.57] x \nDay-to-day activities limited a lot 1.20 [1.16, 1.24] x \nRural/urban classification \n(Reference category: Urban) \nRural 1.02 [1.00, 1.03] 1.02 [1.00, 1.04] \nNotes: Values x are not applicable for the given exposure. For household NS-SEC, “Not classified” includes those not living in a private household in Census \n2011, occupations not stated or inadequately described, or not classifiable for other reasons. For highest level of qualification, “Not classified” includes \nthose aged under 16 in Census 2011. \n \n \n . CC-BY-NC-ND 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted December 12, 2024. ; https://doi.org/10.1101/2024.12.11.24318835doi: medRxiv preprint","source_license":"CC0","license_restricted":false}