Education level is associated with the occurrence and timing of hysterectomy: A cohort study of Canadian women.

All authors contributed to the conception and design of the work, and the acquisition, analytic plan, and interpretation of the data for the work. Beili Huang performed data cleaning and statistical analysis. Erin Brennand drafted the manuscript. All of the authors revised it critically for important intellectual content, gave the final approval of the version to be published, and agreed to be accountable for all aspects of the work.

The Alberta's Tomorrow Project study was approved by the Health Research Ethics Board of Alberta at Alberta Innovates (HREBA.CC‐17‐0461 and HREBA.CC‐17‐0494). This secondary analysis was approved by the Conjoint Health Research Ethics Board at the University of Calgary (REB23‐1521) on October 26, 2023.

This work was conducted as part of the Alberta Sex, Gender and Women's Health Hub, which is funded by the Canadian Institutes of Health Research and Women and Gender Equality Canada through the National Women's Health Research Initiative: Coalition‐Hubs competition (Grant # 189301).

Among 30 496 women in the sample, 39.1% of women reported having a high school education or less, 28.9% reported holding a college degree, 23.5% reported a university degree, and 8.5% reported a postgraduate degree. Comparison of health and demographic characteristics across educational attainment groups generally showed a gradient; women with lower educational levels were more likely to be parous, a current smoker, report medical conditions, have shorter duration of hormonal contraception use, and live in rural areas (Table  1 ). Baseline characteristics of Alberta's tomorrow project female participants by education level ( N  = 30 496). Note : 59 missing for infertility, 177 missing for BMI, 212 missing for diabetes, and 98 missing for cardiovascular disease. Proportions were calculated based on participants with available data. Race/ethnicity groups are not mutually exclusive; participants could self‐identify with more than one group. Abbreviation: SD, standard deviation. By the end of study follow‐up, 6976 females (22.9% of the overall sample) reported experiencing hysterectomy and 4576 females (15.4% of the sub‐sample) reported premenopausal hysterectomy. Multivariable modeling showed an inverse association between educational attainment and odds of hysterectomy in a graded fashion. Compared to attainment of a university degree, the adjusted ORs for any hysterectomy were 1.68 (95% CI 1.55–1.82) for a high school diploma or less, 1.58 (95% CI 1.45–1.72) for a college degree, and 0.77 (95% CI 0.67–0.89) for a postgraduate degree. The adjusted ORs for premenopausal hysterectomy were similar in magnitude (Table  2 ). Association of education level and the occurrence of hysterectomy: Summary of odds ratios. Note : Adjusted models controlled for race (Asian, Black, Indigenous, Hispanic, Middle Eastern, and White), area of residence, smoking, parity, duration of oral contraception use in years, and birth year. Numbers of participants who had premenopausal hysterectomy in each group slightly differ from that in Table  1 due to additionally excluded participants in analysis on premenopausal hysterectomy, see flowchart in Figure  1 . Kaplan–Meier survival curves depicted earlier timing of hysterectomy in lower educational levels (Figure  2 ). Multivariable modeling showed an inverse association between educational attainment and timing of hysterectomy in a graded and time‐varying fashion. Compared to a university degree, adjusted HRs before age 58 indicated earlier hysterectomy in women with a high school diploma or less (eg age 40: 1.61, 95% CI 1.49–1.75); similar patterns in adjusted HRs were observed in women with a college degree before age 58 (age 40: 1.53, 95% CI 1.40–1.67). Adjusted HRs from age 31 to 55 indicated later timing of hysterectomy in women with a postgraduate degree (age 40: 0.74, 95% CI 0.63–0.86) (Figure  3 ). The adjusted HRs for premenopausal hysterectomy were similar in magnitude (Figure  4 ). Kaplan–Meier survival curves of hysterectomy and premenopausal hysterectomy by education level. (A) Hysterectomy ( N  = 30 496). (B) Premenopausal hysterectomy ( N  = 29 766). Association of education level and timing of hysterectomy ( N  = 30 496). (A) High school or less vs university degree. (B) College degree vs university degree. (C) Postgraduate degree vs university degree. The reference group is University degree. Adjusted models controlled for race (Asian, Black, Indigenous, Hispanic, Middle Eastern, and White), area of residence, smoking, parity, duration of oral contraception use in years, and birth year. Association of education level and timing of premenopausal hysterectomy. (A) High school or less vs university degree. (B) College degree vs university degree. (C) Postgraduate degree vs university degree. The reference group is University degree. Adjusted models controlled for race (Asian, Black, Indigenous, Hispanic, Middle Eastern, and White), area of residence, smoking, parity, duration of oral contraception use in years, and birth year. Results from the sensitivity analyses exploring geographic location suggested that the protective effect of educational attainment against having a hysterectomy was slightly weaker among the rural population compared to urban for both hysterectomy and premenopausal hysterectomy (Table  S2 , Figures  S2 and S3 ). Results from the sensitivity analyses adjusted for baseline body mass index and chronic medical conditions, as well as the sensitivity analysis stratifying on parity, did not substantively differ from main analyses (Table  S1 , Figures  S2 and S3 ). Sensitivity analysis by birth cohort showed associations were strongest for younger individuals in the cohort.

In this prospective cohort study of Albertan women, level of educational attainment was inversely associated with the occurrence and timing of hysterectomy. When compared to women with a university degree, women with a high school diploma or less had the highest odds of hysterectomy, including premenopausal hysterectomy, and earliest age at surgery, followed by women with a college degree. Associations were attenuated for rural women, suggesting educational disparity in hysterectomy is more pronounced for those living in urban areas. Our findings are consistent with a meta‐analysis of 10 studies published between 1991 and 2005, which reported that risk of hysterectomy was elevated by 17% for each reduction in education level. 30 Our data are also aligned with an Ontario study reporting a gradient between lower neighborhood‐level educational attainment quartiles and higher hysterectomy rates. 26 Our study adds to the literature by showing that the inverse association between individual‐level education and hysterectomy is also observed for premenopausal hysterectomy and earlier timing of surgery over the life course. Through use of flexible survival analysis to account for variations in risk over time, we further demonstrated that educational disparities in hysterectomy are observed almost exclusively before age 60 years with the largest differences occurring in early adulthood. This novel finding is clinically important because hysterectomy specifically before menopause and at younger ages is associated with the worst consequent long‐term health outcomes. Our data raise concern that the burden of chronic diseases and menopausal symptoms that are disproportionately experienced by older women with lower educational attainment could be partly attributable to hysterectomy rates. 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 30 , 39 There are numerous possible explanations for our findings. Economic reasons may play a role given the close relationship among education, income, and job stability. 40 For example, women with lower education may be less likely to have extended health benefits that cover the cost of medical treatments, 41 , 42 resulting in an initial decision to undergo publicly funded surgery or in untreated disease worsening to eventually require surgery. Social and cultural reasons underlying an inverse association between education and hysterectomy are complex. Women with lower educational levels may be less likely to be offered hysterectomy alternatives 43 ; gynecologists may implicitly or explicitly hold a sentiment “that it is often more efficient, and possibly less expensive, to operate [on socially disadvantaged women] than to take the time to educate a patient and to treat medically.” 44 Women with lower education levels may experience lower health literacy, 45 which could impact the timeliness with which they seek and access care, 43 as well as their capacity to be fully involved in treatment decisions. For example, low health literacy may limit women's ability to synthesize the risks and benefits of hysterectomy and promote deference to physician‐directed decision‐making. 46 , 47 , 48 More broadly, hysterectomy appears to be culturally normalized in Canada. In the most recent year of federal surveillance (2022), the rate of hysterectomy in Alberta was >20% higher than the national rate (328 per 100 000 females aged 18 or older in Alberta vs 269 per 100 000 in Canada); in fact, review of data from 2010 onward reveals that Alberta has consistently exceeded Canada's national hysterectomy rate. 49 A series of qualitative interviews with Albertan women planning surgery for pelvic organ prolapse revealed common beliefs that there is no purpose for the uterus after childbirth and no medical reasons for avoiding hysterectomy other than psychological “attachment” to the organ as a feature of “womanhood.” 50 Some women electing hysterectomy reported encouragement from family or friends who had undergone the procedure, whereas other women with no strong opinion on the removal of their uterus reported acting on the recommendation of their surgeon. 50 Similar influences on hysterectomy decision‐making have been reported in other jurisdictions. 51 , 52 Social acceptance of hysterectomy likely provides an important backdrop within which provider bias toward hysterectomy and suboptimal patient engagement in decision‐making gives rise to educational and other social disparities in use of this procedure. Strengths of this study include the large community‐based sample and detailed sociodemographic (eg education and race) and menopause data that, to our knowledge, are not simultaneously available in any Canadian population‐based data sources such as health claims or national surveys. However, several limitations should be considered. Foremost, these data are self‐reported and subject to inherent measurement error. Educational attainment measured at baseline may have differed from educational attainment at the time of hysterectomy; it could have been misclassified as higher for women who experienced hysterectomy at a younger age or who returned to school later in life, which could have biased odds and hazard ratios (Table  3 ) toward the null. Recall bias in age at hysterectomy and menopause is possible; however, women's retrospective self‐report of reproductive health history generally has moderate‐to‐high accuracy over two decades later. 53 , 54 , 55 , 56 Absence of data on underlying gynecologic conditions for hysterectomy and additional socioeconomic variables such as income and occupational group precluded us from accounting for these factors in our study. Finally, when compared to the Albertan female population, the ATP sample used in this study under‐represented women from diverse race or ethnic groups, 31 , 57 which is a common external validity issue in recruitment‐based longitudinal research including seminal cohort studies in women's health. 58 , 59 Additional research with racially representative datasets is needed to corroborate our findings and examine intersections among race, education, and gynecologic health in Canada. Association of education level and timing of hysterectomy and premenopausal hysterectomy: Summary of hazard ratios. Note : Adjusted models controlled for race (Asian, Black, Indigenous, Hispanic, Middle Eastern, and White), area of residence, smoking, parity, duration of oral contraception use in years, and birth year. This study is part of a growing literature on social determinants of hysterectomy in Canada, 26 , 60 , 61 which collectively calls for greater attention to addressing inequities in gynecologic surgery across the country. The addition of female reproductive health variables to Canada's national health surveillance survey program (the Canadian Community Health Survey) could enable detailed insights into hysterectomy patterns by patient, geographic, and social factors. Primary research on physicians' preferences, explicit and implicit biases, and knowledge of the evidence (eg downstream impacts) on hysterectomy, as well as pertinent reimbursement structures that may influence treatment recommendations, 15 could inform provider educational strategies to support judicious use of this procedure. Co‐designed patient‐oriented materials such as decision aids 62 would be a valuable health equity resource. 63 , 64 These materials should be developed using best practices in health literacy, 47 , 65 and aimed at clear communication of risks and benefits, determination of personal values and sources of influence, and empowering patient involvement in treatment decisions.

This study demonstrated that Albertan women with lower educational attainment were more likely to have a hysterectomy than women with a university degree, with surgery frequently occurring before menopause and at younger ages on average. These findings add to the growing evidence of social disparities in hysterectomies in Canada which require timely action. Multifactorial work is needed to fully understand the drivers of inequitable hysterectomy use and to support evidence‐based, shared decision‐making for female reproductive health.

Hysterectomy, the surgical removal of the uterus, is the second most frequently performed surgery among females, surpassed only by cesarean section. 1 In Canada, approximately 35 000 hysterectomies are performed annually, 2 with a considerable cost burden of $200 million CAD. 3 Most patients (90%) undergo hysterectomy for treatment of noncancerous gynecologic conditions such as heavy uterine bleeding, fibroids, endometriosis, or pelvic organ prolapse. 4 Hysterectomy rates have steadily declined due to increased medical management of these conditions, 5 , 6 , 7 , 8 , 9 yet practice variation in the use of hysterectomy persists. 10 , 11 , 12 This variation suggests that some hysterectomies may be avoidable, resulting from differences in use of alternatives to hysterectomy due to patient preferences for surgery and provider practice 13 , 14 , 15 or accessibility of alternative treatments. Understanding the sources of variation in hysterectomy use is necessary to resolve disparities in receipt of this major surgery and its potential harm to women's long‐term health. Increasing evidence has shown that hysterectomy is associated with an increased long‐term risk of cardiovascular and metabolic conditions such as hypertension, coronary artery disease, osteoporosis, and dementia, and earlier vasomotor symptoms of menopause (eg hot flashes) when compared to females who have not had their uterus removed. 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 These increased risks are present even when ovaries are conserved, and are inversely proportional to the age at which the hysterectomy is performed. 25 Growing evidence has documented social determinants of hysterectomy for noncancerous conditions, including rural vs urban residence, 12 , 15 , 26 , 27 income, 13 insurance status, 28 and patient race/ethnicity. 14 , 29 A meta‐analysis found that females in the lowest category of education attainment were almost twice as likely to have a hysterectomy, with evidence of a possible dose–response‐type relationship between education level and lifetime hysterectomy risk. 30 The review included data from nine industrialized nations, not including Canada. Moreover, few studies on social determinants have accounted for the timing of hysterectomy over a female's life course and in relation to menopause, which would elucidate how downstream health risks may be pronounced in certain subgroups of the population. As such, we sought to explore the relationship between educational attainment and the occurrence and timing of hysterectomy in a contemporary cohort of women in Alberta, Canada. We hypothesized that educational attainment would be inversely associated with odds of hysterectomy, including hysterectomy before menopause, and would be associated with a younger age at time of hysterectomy.

Erin Brennand and Natalie Scime report receiving grant funding from the Canadian Institutes for Health Research which supported this study (paid to institution). Erin Brennand reports receiving grant funding from the Canadian Institutes for Health Research, Social Sciences and Humanities Research Council, the Calgary Health Foundation, and the MSI Foundation (paid to institution), outside the submitted work. Erin Brennand reports salaried employment with Alberta Health Services for the role of Calgary Zone Department Head—Obstetrics and Gynecology. Natalie Scime holds a Banting Postdoctoral Fellowship, which supports salary. No other competing interests were declared.

We conducted a secondary analysis of the Alberta's Tomorrow Project (ATP), a province‐wide prospective cohort study aimed at investigating etiology and healthcare utilization related to cancer and chronic diseases. 31 Between 2000 and 2015, a total of 52 810 people aged 32–71 years with no history of cancer ( n  = 34 950 females) were recruited into ATP using two‐stage telephone random digit dialing (from 2000 to 2008) and volunteer sampling (from 2009 to 2015). Self‐reported questionnaires were used to collect comprehensive information on participants' demographic characteristics, health history, chronic diseases, lifestyle, social determinants, and healthcare use at baseline and on an ongoing basis through follow‐up approximately every 4 years. 32 For this secondary analysis, we used data from the two largest baseline questionnaires and all follow‐up questionnaires completed by October 2022. Healthcare in Alberta (and all of Canada) is provided through a publicly funded system that provides universal coverage to all residents, covering the cost of physician visits and hospital admissions, including surgical procedures. Individuals do not pay directly for insured health services; rather the system is funded through federal and provincial/territorial taxation, ensuring that healthcare is provided based on need rather than ability to pay. We included female participants who provided data on education level and hysterectomy status, excluding participants who reported hysterectomy at a young or implausible age (<20 years) or who were missing covariate data (Figure  1 ). This resulted in a sample size of 30 496 women. For the analysis of hysterectomy specifically before menopause, we additionally excluded participants with unknown temporal ordering of hysterectomy and menopause or an extreme age at menopause (>65 years), resulting in a subsample size of 29 766 females. Flow diagram of included female participants from Alberta's Tomorrow Project. *Health and Lifestyle Questionnaire (HLQ) and CORE baseline questionnaires, which included questions on all covariates in our analysis. The exposure was highest level of education attainment self‐reported at baseline and categorized into four levels: high school diploma or less, college degree, university degree (reference group), and postgraduate degree. In Canada, college programs are often more career oriented and practical, designed to prepare students for specific jobs or industries through certificates and diplomas, as well as associate and bachelor degrees with a duration of 2–4 years. Universities offer undergraduate degrees typically of 4 years length, which are generally more research based and theoretical, focusing on analytical skills and broader academic knowledge. The outcomes were occurrence and timing of hysterectomy self‐reported at baseline and each follow‐up, including the age at which the procedure took place any time before or during the study period. Premenopausal hysterectomy was defined as hysterectomy occurring before natural or surgical (bilateral oophorectomy) menopause. Clinical indication for hysterectomy was not collected. Sociodemographic and reproductive health factors were self‐reported at baseline. Covariates for adjusted models were selected based on prior evidence and included: birth year (continuous in years), 30 area of residence (rural vs urban), 12 , 15 , 26 , 27 parity (0, 1, 2, or ≥3 births), 33 smoking status (never, past, or current), 34 duration of hormone contraception use (continuous in cumulative years), 35 and race/ethnicity. 14 , 29 Race/ethnicity was measured with binary indicators for Asian, Black, Hispanic, Indigenous, Middle Eastern, and White based on self‐identified ethnic group(s), which were not mutually exclusive. 36 We first analyzed the association between education level and occurrence of hysterectomy (any and premenopausal) using logistic regression. We estimated odds ratios (ORs) and 95% confidence intervals (CIs), unadjusted and adjusted for age at baseline, area of residence, parity, smoking status, duration of hormone contraception use, and race/ethnicity. We then analyzed the association between education level and timing of hysterectomy (any and premenopausal) using flexible parametric survival analysis, with age as an underlying time scale and counting person–time at risk in years from age 20 years to the age at hysterectomy or censoring. 37 Censoring events for any hysterectomy were attrition or end‐of‐study follow‐up. Censoring events for premenopausal hysterectomy additionally included natural menopause and surgical menopause. We allowed associations to vary over time using restricted cubic splines; we predetermined four degrees of freedom for baseline hazard and optimized the number of degrees of freedom for the time‐varying effect using Akaike information criterion. We estimated crude Kaplan–Meier survival curves as well as hazard ratios (HRs) and 95% CIs (HR >1 signifies earlier timing of hysterectomy), unadjusted and adjusted for area of residence, parity, smoking status, duration of hormone contraception use, and race/ethnicity. We conducted four sensitivity analyses for all models. First, we explored whether the associations differed in rural vs urban populations, recognizing that social and systemic structures between education and rurality may intersect and overlap. 38 We separately stratified the logistic and survival models by geography of residence and incorporated multiplicative interaction terms in the logistic and survival models. Second, we adjusted for baseline body mass index and chronic medical conditions, which could potentially account for the associations of interest but may not have temporally preceded hysterectomy depending on each participant's health trajectory and age at baseline. Third, given that women with lower educational attainment had higher parity, we stratified by parity to ensure results were not entirely due to childbearing factors alone. A fourth sensitivity analysis by birth year, grouping ages into birth cohorts, was performed to explore for impact of improved medical treatments for uterine conditions as older women are less likely to have benefitted from recent research and development in gynecologic therapeutics. Data cleaning, analysis, and figure generation were conducted in R version 4.2.2 (R Core Team, 2022).

Figure S1. Table S1.