{"paper_id":"58d88d06-dd61-43c5-9a47-b4bc37f601e2","body_text":"Chronic pelvic pain (CPP) is a highly prevalent and debilitating clinical condition with\na significant impact on the social, working and family activities of women, negatively\naffecting their quality of life. Some factors contribute to the variability of\nprevalence, among them the characteristics and quality of the studies, the definition\nused, the prevalence of sexually transmissible diseases, and the cultural\ncharacteristics of the population studied ( 1 ).\nThe prevalence rates have ranged from 2.1 ( 2 , 3 ) to 43.4% ( 4 ). The studies reporting them are heterogeneous, nevertheless, a\nhigh quality study found a prevalence rate of 24% ( 5 ). It is a clinical condition whose cause in most cases is not identified\nand usually results from a complex interaction between the gastrointestinal, urinary,\ngynecological, musculoskeletal, neurologic, psychological and endocrine systems, and is\nadditionally influenced by sociocultural factors. Any abdominal and/or pelvic region may\nbe involved in the etiology of CPP, with no consensus existing about the diseases that\nmay cause it, although endometriosis, interstitial cystitis, pelvic inflammatory\ndisease, irritable bowel syndrome, constipation and pelvic adhesions are those most\noften associated with it ( 6 ).\nIn a recent systematic review, Latthe et al. ( 7 )\nobserved that drug or alcohol abuse, miscarriage, heavy menstrual flow, pelvic\ninflammatory disease, previous cesarean section, pelvic pathology, abuse, and\npsychological comorbidity were associated with an increased risk of noncyclical pelvic\npain. However, few survey studies worldwide have evaluated the condition. Our group\nobserved a prevalence of approximately 11% in the Southeast of Brazil, and identified as\nassociated independent conditions: dyspareunia, previous abdominal surgery, depression,\ndysmenorrhea, anxiety, current sexual activity, low back pain, constipation, irritative\nurinary symptoms, and low educational level ( 8 ).\nWe believe that this information is important because our country shares many\ncharacteristics with other developing countries around the world. However, Brazil is a\nvast and culturally heterogeneous territory, so that the conclusion of that study alone\ncannot be generalized to the country as a whole. Furthermore, some conditions, such as\neducational level, are not similar in all States or Regions of Brazil. Because of this,\nhealthcare policies may be different in order to set targets to prevent or minimize the\noccurrence or impact of CPP. Recently, the University Hospital at São Luís created a\nservice specialized in the care of women with CPP in response to a request from health\nprofessionals in the region. On this basis, we carried out the present study with the\naim of investigating the community prevalence of CPP in São Luís, Brazil, as well as\neventual clinical conditions associated with it.\n\nThis was a cross-sectional survey study conducted during the period from June 2009 to\nMay 2010. It followed the Declaration of Helsinki set of principles and was approved\nby the Local Research Review Board. All subjects or those responsible for them gave\nwritten informed consent to participate.\nThe subjects were recruited in the urban area of the municipality of São Luís,\ncapital of the State of Maranhão, Northeastern Brazil, with an estimated population\nof 1,014,837 inhabitants, 539,842 of them women (53.2%). According to the latest\ndemographic census (2010) ( http://cidades.ibge.gov.br/xtras/perfil.php?lang=&codmun=211130&search=||infogr%E1ficos:-informa%E7%F5es-completas ),\n511,515 of these women (94.8%) are estimated to live in the urban zone. A total of\n876,826 inhabitants residing in the municipality (86.4%) are literate and the mean\nhousehold per capita income is R$645.00 (approximately US$360.00), while the median\nis R$430.00 (approximately US$240.00).\nThe study included 1470 women who were interviewed at home. The target population\nconsisted of women who use exclusively the Unified Health System. Only women aged at\nleast 14 years and having had menarche were included in the study. The maximum age\nwas 60 years.\nWe adopted the definition of CPP proposed by the American Congress of Obstetricians\nand Gynecologists (ACOG): “A noncyclic pain of 6 or more months' duration that\nlocalizes to the anatomic pelvis, anterior abdominal wall at or below the umbilicus,\nand is of sufficient severity to cause functional disability or lead to medical\ncare”. All women with a diagnosis of the condition were referred to the city hospital\nspecializing in women's health and the diagnosis was confirmed before inclusion in\nthe data bank.\nThe visual analogue scale (VAS) was used to assess the intensity of pain, an\ninstrument extensively employed in clinical practice because of its rapid use and\nclinical applicability. We considered patients to have significant pain when their\nVAS score was 30 mm or higher and when they had at least one pain episode per\nweek.\nThe variables evaluated were grouped as social, economic, and cultural: age, skin\ncolor (self-reported), per capita income, employment, marital status, educational\nlevel, physical activity (women who engaged in activities such as running, walking,\npedaling, dancing, or other sport activity for at least 150 min a week; according to\nthe World Health Organization < http://www.who.int/topics/physical_activity/en/ >), caffeine intake,\nalcoholism (excessive intake during the weekend with frequent drunkenness and/or\ndaily consumption with or without drunkenness), smoking (current or former daily\nsmoker), and illicit drug use.\nSexual, menstrual and obstetric history : menstrual status, age at\nmenarche, age at menopause, menstrual cycle (number of days), regularity of menstrual\nflow (volume: divided into increased or reduced subjectively; duration: normal when\nit lasted from 2 to 8 days), spotting (intermenstrual bleeding considered when\npresented in most cycles in the last 6 months), dysmenorrhea, previous sexual\nactivity, age at first sexual intercourse, infertility (defined as proposed by the\nWHO when the woman has not become pregnant after 2 years of regular sexual\nintercourse, without contraception), parity, episiotomy, forceps, cesarean section,\nmiscarriage, puerperal complications, current sexual activity, contraception, sexual\ndisorders (hypoactive sexual desire, anorgasmia, female sexual arousal disorder, and\ndyspareunia), sexual and physical violence.\nClinical conditions and other antecedents : PHQ-4 (Patient Health\nQuestionnaire: a 4-item measure of symptoms of depression) ( 9 , 10 ), urinary symptoms\n(frequency, urgency, nocturia, incontinence), intestinal symptoms (functional bowel\ndisorders by Rome III criteria) ( 11 ):\nconstipation, bloating, diarrhea, and blood in stool; comorbidities previously\ndiagnosed such as inflammatory pelvic disease, migraine, low back pain, repetition\nurinary tract infection (three or more episodes in the last year), urinary calculi,\nleiomyomatosis, depression, diabetes mellitus, chronic hypertension, abdominal\nsurgeries (number and incision type), perineal surgeries (such as colpoplasty,\nhemorrhoidectomy), uterine surgeries (such as curettage, hysteroscopy).\nA questionnaire was chosen as the collection instrument because it is applicable to\nall segments of the population studied, which is quite heterogeneous, containing both\nilliterate and literate people. The interviews were held in a private environment.\nThe interviewers, who were not affiliated with the city health care programs, were\ntrained and selected by the researcher responsible for the study. The data collected\nby the interviewers were entered during the interview and sent to an electronic\ndatabase (software Filemaker ¯  Pro Advanced 8, USA). Five percent of the\nsubjects were selected at random and re-interviewed to check data consistency.\nIndependent investigators who did not participate directly in data collection carried\nout the analyses. All women with symptoms suggestive of chronic pelvic pain during\nthe interview were sent to specialized service in order to confirm the diagnosis by a\nphysician. Two women did not attend, but a physician visited them and he did not\nconfirm the diagnosis due to absence of symptoms.\nSample selection was random by cluster sampling (stratification by area and estimated\npopulation density) in a stepwise manner. The sampling process consisted of areas\nchosen at random by drawing lots after analysis of maps of the city neighborhoods,\nfollowed by systematic sampling with a withdrawal interval proportional to the number\nof residences and local population density. All women in the household were invited\nto participate in the study.\nThe sample size was defined considering a population estimated of 539,842 women,\nconfidence interval of 95% (95%CI), maximum error of 1%, and estimated prevalence\nrate of 4%.\nStatistical analysis was performed using the SAS ¯  9.0 software (USA).\nAnalysis of the quantitative variables was performed by the Mann-Whitney test after\nsome variables were found not to have normal distribution according to the\nKolmogorov-Smirnov test, while qualitative variables were analyzed by the Fisher\nexact test or the chi-square test.\nLogistic regression was used to identify the significant and independent variables\nand to estimate the simultaneous association of these factors in CPP. All variables\nwith a P<0.10 in bivariate analysis and those we considered to be plausible to\njustify the pain and that were significant in other studies ( 7 , 8 ) were included in a\nlogistic regression model. Simple and multiple logistic regressions were used to\nestimate the odds ratio. The analysis was carried out using the PROC LOGISTIC\nprocedure of the SAS ¯  9.0 software and the best model observed was\npresented. We also report the 95% confidence interval, considering P<0.05.\n\nThe characteristics of the subjects and the univariate analysis are presented in\n Tables 1 ,  2 , and  3 . Because of wide\nvariability, it was not possible to divide the professional activities into groups.\nThe activities most frequently reported were: student (23.6%), housewife (16.6%),\nmaid (11.3%), retired (5.7%), teacher (5.4%), self-employed professional (3.5%),\nnurse technician (2.8%), storekeeper (2.6%), saleswoman (2.6%), and public servant\n(2.4%), among others.\nThe 1-year prevalence of CPP in São Luís, Brazil, was 19.0% (279/1470). The women\nwith CPP had been symptomatic for 47.8±66.3 months (median: 20, range: 6-360 months)\nand presented an intensity of 63.2±20.0 mm (median: 60, range: 30-100 mm), with 8.6%\n(n=24) of them having symptoms compatible with allodynia.\nA total of 58.4% (n=163) of the women stated that they took analgesics on a weekly or\ndaily basis (paracetamol/acetaminophen/dipyrone) and/or non-steroidal\nanti-inflammatory drugs (NSAIDs) without a medical prescription.\nIn logistic analysis, the independent variables associated with CPP were:\ndyspareunia, premenopausal status, patient health questionnaire above 5,\ndysmenorrhea, smoking, irregular menstrual flow, and irritative bladder symptoms. The\nresults of multivariate analysis are reported in detail in  Table 4 .\n\nThe prevalence of CPP was 19.0% in the subjects of this study. Our two studies showed\nthat Brazil is one of the countries with a higher prevalence of the condition,\nparticularly in contrast to developed countries ( 7 , 8 ). In addition, a large part of the\nsample routinely used painkillers without a medical prescription, which predispose to\nseveral undesirable events, including financial expenditures without guarantee of\nclinical improvement.\nWe observed a significant association with dyspareunia, premenopausal status, patient\nhealth questionnaire score, dysmenorrhea, smoking, irregular menstrual flow, and\nirritative bladder symptoms. Most of them are associated symptoms and, probably are not\nsufficient to cause CPP. Our results also suggest that a history of previous perineal\nand uterine surgery are important elements associated with the development of CPP.\nHowever, some OR values did not converge due to sample size and the frequency of some\ncharacteristics.\nMost of the associated conditions are symptoms without potential of causality.\nAlthough it is important to know them, it is necessary to reflect on the complexity\nof the determinants of the condition. The presence of dyspareunia, a high prevalent\ncondition (7 to 75%) ( 12 , 13 ), was significantly higher in women with CPP. In a recent\nstudy, we had also observed that dyspareunia was associated with pelvic muscle\ntenderness ( 14 ). Although pelvic muscle\ntenderness may be a primary cause of CPP, we hypothesize that it is more often\nsecondary to cross-talk communication between the viscera and muscles ( 15 ). The high prevalence of a history of a\ndiagnosis of pelvic inflammatory disease in the last year, which in turn may explain\nthe infertility rates, may also explain the occurrence of dyspareunia. That\ncondition, in detriment of this last, was not confirmed in the adjusted model as an\nindependent variable, probably due to overlap between them.\nDepression disorders are frequently concomitant with chronic pain, particularly in\nwomen ( 16 ). The idea that pain, particularly\nchronic pain, can lead to feelings of frustration, worry, anxiety, and depression\nseems obvious. There is some evidence that it is the stress of living with chronic\npain, and not personal or family predisposition, that causes depression in these\npatients ( 17 ). It, therefore, remains\nuncertain whether depression precedes or is a consequence of chronic pain ( 18 ).\nDysmenorrhea is a condition that is frequently concomitant with CPP. Its association\nwith endometriosis or adenomyosis may explain the relationship to CPP ( 19 ). Several other hypotheses may be raised and\nwe emphasize two that we believe to be more plausible: 1) low pain thresholds in\nwomen with CPP and dysmenorrhea ( 20 ) or even\ncentral sensitization induced by the primary disease ( 21 ) may favor the higher prevalence of dysmenorrhea in this group; 2)\nuterine inflammation secondary to neurogenic inflammation that is evident in animal\nmodels may result in viscero-visceral hyperalgesia between organs ( 22 ), a fact that may also explain uterine\nsensitivity in humans.\nMore recently, it has been discovered that smoking is a risk factor for chronic pain.\nAnother epidemiological study conducted in Brazil also observed that smoking is an\nindependent factor associated with chronic pain conditions ( 23 ). Robust epidemiological evidence is showing that smokers not\nonly have higher rates of chronic pain but also rate their pain as more intense than\nnonsmokers ( 24 ). It has been observed that the\nact of smoking may be a way of dealing with stress and the already present\nlong-lasting pain (coping strategy) ( 25 ). In\nthe present study, smoking was a more important factor than alcohol drinking, though\nthe latter is also an element significantly associated with chronic pain conditions\nand with smoking itself. Abnormal menstrual bleeding is a prevalent clinical problem\namong women of reproductive age.\nIn contrast to what we observed in Ribeirão Preto ( 8 ), we did not observe previous abdominal surgery and low educational\nlevel as independent factors. Regarding the former, although an association is\nplausible, we do not know if other confounding variables or even cultural aspects may\nhave interfered with the results. Curiously, the presence of a previous abdominal\nsurgery was not a variable associated with the condition, at least in this sample,\neven though a history of three or more previous abdominal surgeries was two times\nmore frequent among women with CPP. Almost 40% of the women interviewed had already\nbeen submitted to at least one previous abdominal surgery. We consider this\nprevalence to be a potential source of concern. A quarter of the women had given\nbirth by cesarean section. Thus, we emphasize the importance of recognizing abdominal\nmyofascial syndrome and the neuralgias, particularly ilioinguinal and iliohypogastric\nones, as a differential diagnosis ( 26 ).\nRegarding the second factor (educational level), the high frequency of subjects who\nhad not concluded elementary school in both groups (almost 20%) may have influenced\nthe findings.\nSexual, emotional, or physical abuse, particularly childhood sexual abuse, has been\nlinked to CPP and to sexual dysfunction ( 27 ).\nAlthough many authors and clinicians have mentioned this association, it has also\nbeen suggested that both physical and sexual abuse may be associated with\npsychological distress in women with CPP but not with other domains of pain\nexperience ( 28 ). Further studies in this field\nare essential to clarify the relationship between history of both abuse and violence\nand the development and promotion of chronicity of CPP.\nNone of the women contacted refused to respond to the questionnaire, a fact that\nmakes the results reliable, at least from the viewpoint of sample representation. All\nwomen had diagnosis confirmed by a physician before inclusion in the study. On the\nother hand, the questionnaire covers responses that are always subjective and that\nrequire memories and truthfulness. We believe that the accuracy of the information\nhas been maintained because interviews were conducted in private and in a home\nenvironment of the participant.\nOur study has identified that prevalence of CPP in São Luís is high and several\nindependent conditions were associated with it. However, most of them are associated\nsymptoms and, investigation of a possible causal relationship is essential. We\nbelieve that CPP is a condition determined by a complex interaction of numerous\nfactors. Although abdominal surgeries and functional disorders of the intestine were\nnot identified in the present study, we believe that special attention should be paid\nto this question. Further studies are necessary to corroborate our results.","source_license":"CC-BY-4.0","license_restricted":false}