A prospective study of body size during childhood and early adulthood and the incidence of endometriosis

Assessing the true prevalence of endometriosis: A narrative review of literature data

Endometriosis is a gynecologic condition often described as the "chameleon of gynecology" because of its elusive symptoms. The World Health Organization acknowledges its severe impact on quality of life due to pain, fatigue, depression, and infertility. There is limited literature on the prevalence of endometriosis, knowledge of which is essential for effective prevention, treatment strategies, and funding. We aim to structure and present the published data on endometriosis prevalence, synthesizing the discrepancy between health insurance and clinical data. PubMed, Cochrane CENTRAL, and LIVIVO were researched for peer-reviewed articles published between January 2000 and July 2023 on women of reproductive age. Health insurance companies argue that few women (~1%) are affected by endometriosis. Interestingly, the prevalence of clinical data studies (6.8%), population-based surveys/self-reported studies (6.6%), and symptomatic patient data (21%) revealed a different picture. Based on the data gathered, a multi-layered prevalence model has been proposed to illustrate the large discrepancy in the prevalence numbers, leading to the disease being underestimated and underfunded. This variability may be influenced by the heterogeneity in designs and the analyzed data, and clinical complexity. In summary, this narrative review reveals that the prevalence of endometriosis is higher than health insurance and other stakeholders might have previously assumed.

The mysterious association between adiponectin and endometriosis

Adiponectin is a pleiotropic cytokine predominantly derived from adipose tissue. In addition to its role in regulating energy metabolism, adiponectin may also be related to estrogen-dependent diseases, and many studies have confirmed its involvement in mediating diverse biological processes, including apoptosis, autophagy, inflammation, angiogenesis, and fibrosis, all of which are related to the pathogenesis of endometriosis. Although many researchers have reported low levels of adiponectin in patients with endometriosis and suggested that it may serve as a protective factor against the development of the disease. Therefore, the purpose of this review was to provide an up-to-date summary of the roles of adiponectin and its downstream cytokines and signaling pathways in the aforementioned biological processes. Further systematic studies on the molecular and cellular mechanisms of action of adiponectin may provide novel insights into the pathophysiology of endometriosis as well as potential therapeutic targets.

Eating Disorders and Disturbed Eating Behaviors Underlying Body Weight Differences in Patients Affected by Endometriosis: Preliminary Results from an Italian Cross-Sectional Study

This study aimed to characterize the prevalence of eating disorders (EDs), disturbed eating behaviors (DEBs), and emotional eating attitudes (EEAs) among patients affected by endometriosis in order to understand a potential crosslink between this impacting gynecological disease and a Body Mass Index shift. A total of 30 patients were recruited at an endometriosis outpatient clinic in Bologna and were assessed by using standardized instruments and specific questionnaires for EDs, DEBs, and EEAs. Sociodemographic information and endometriosis clinical features and history information were collected by adopting a specific questionnaire. Retrospective reports of lifetime Body Mass Index (BMI) changes, current BMI, peak pain severity during the last menstrual period, and the average of pain intensity during the last intermenstrual period were used for a correlation with the mean score from eating-behavior scales' assessment. The preliminary results indicate that, although only 3.33% of endometriosis patients are affected by ED, statistically significant differences at the mean scores of DEBs and EEAs assessment scales were found by stratifying patients on the basis of BMI levels at risk for infertility and coronary heart disease and on the basis of moderate/severe pain levels. The enrichment of the sample size and the recruitment of the control group to complete the study enrollment will allow us to investigate more complex and strong correlation findings and to assess the prevalence of EDs among endometriosis patients.

Body mass index and the diagnosis of endometriosis: Findings from a national data linkage cohort study

BACKGROUND

Women with lower body mass index (BMI) have a higher risk of surgically confirmed endometriosis but this finding runs counterintuitive to the oestrogen-dependent theory for the disease. Increasingly, endometriosis is diagnosed via non-surgical methods. We examined BMI at age 18-23 years, and changes in BMI, and the risk of endometriosis according to the diagnostic method.

METHODS

We analysed data from 11 794 young women, born in 1989-95, who completed six surveys as part of an Australian, longitudinal cohort study between 2013 and 2018. Women's survey responses were linked to administrative health records to identify endometriosis. Cox proportional hazards models modelled associations between BMI at age 18-23 years, and changes in BMI, and endometriosis. Analyses were stratified by the diagnostic method of endometriosis: clinically confirmed endometriosis (based on hospital discharge diagnosis) versus clinically suspected endometriosis (women's reports of physician-diagnosed endometriosis).

RESULTS

There were 223 cases of clinically confirmed endometriosis and 396 cases of clinically suspected endometriosis. Women who gained weight after age 18-23 had lower risk of clinically confirmed endometriosis than women without endometriosis whose weight remained stable (HR = 0.64, 95% CI = 0.47-0.88). Women who were overweight (HR = 1.29, 95% CI = 1.01-1.66) at age 18-23 had higher risk of clinically suspected endometriosis than women of normal weight without endometriosis.

CONCLUSIONS

The risk of clinically confirmed endometriosis was lower among women who gained weight compared to women with stable weight. The risk of clinically suspected endometriosis was higher among women who were overweight compared to normal weight.

Body mass index and endometriosis: Is there a relationship?

Objective:

Previous studies on the relationship between the presence of endometriosis (EM) and body mass index (BMI) have shown inconsistent results. This study aimed to compare the BMI between women with EM and non-endometriotic controls.

Methods:

In the present cross-sectional study, BMI of 65 endometriotic women with 43 non-endometriotic controls undergoing laparoscopy were compared. The comparison of BMI between the two groups and in disease stages was analyzed using t-test.

Results:

BMI was significantly lower in women with EM compared to control women ( p = 0.01). There were no statistically significant differences in BMI between disease stages.

Conclusion:

The present study results showed that women with EM have lower BMI compared to non-endometriotic controls. More studies are suggested to clarify the mechanisms of this association.

Pediatric and adult obesity concerns in female health: a Mendelian randomization study

PURPOSE

Adulthood and childhood obesity are both associated with reproductive diseases and gynecological cancers in females. However, the causal factors associated with these observations have yet to be identified. Mendelian randomization is a process that is independent of inverse bias and confounding and can act as a random control trial in which genetic groups are settled during meiosis, thus representing an effective tool with which to investigate causality.

METHODS

We carried out several Mendelian randomization trials based on the combined genetic scores of 75 adult-associated and 15 childhood-associated body mass index (BMI) single nucleotide polymorphisms (SNPs), databases for several gynecological cancers and reproductive diseases from the UK Biobank (with 194,153 participants), using the traditional inverse-variance weighted (IVW) method as the main method.

RESULTS

Elevated adult-associated BMI scores (odds ratio [OR] = 1.003; 95% confidence interval [CI]: 1.001-1.004) and childhood-associated BMI scores (OR = 1.003; 95% CI: 1.001-1.004) were related to a higher risk of the polycystic ovarian syndrome (PCOS), as determined by the traditional IVW method. The random IVW method further revealed a nominal negative causal association between childhood-associated BMI and subsequent endometriosis (OR = 0.995; 95% CI: 0.991-0.999).

CONCLUSIONS

Consistent with observational consequences, our findings indicated that adulthood obesity may play role in the development of PCOS and that childhood obesity can increase the risk of PCOS but may reduce the incidence of endometriosis in later life. Further research is now needed to validate our findings and identify the precise mechanisms involved.

What is the link between endometriosis and adiposity?

Endometriosis is defined by the presence of extrauterine endometrial tissue and presents with symptoms of dysmenorrhea, chronic pelvic pain, and impaired fertility. This condition often follows a chronic progressive course with favorable recurrence, even after surgical or medical treatment. The etiology or exact pathophysiology of endometriosis remains to be clarified, although it is thought to be a complex and multifactorial disease. Prior epidemiological or population-based studies have reported several risk factors related to endometriosis, such as environmental, menstrual, habitual, and lifestyle factors. Moreover, anthropometry has been found to be significantly associated with the diagnosis of endometriosis, as a lower body mass index is associated with an elevated risk of endometriosis. Here, we review studies that have examined the association between body size and the risk of endometriosis and discuss the clinical and biological significance of the relationship between adiposity and endometriosis.

Associations between body mass index and the surgical phenotype and location of endometriotic lesions

RESEARCH QUESTION

Is there a relationship between body mass index (BMI) and endometriotic lesions, specifically surgical phenotype and lesion location?

DESIGN

An observational retrospective cohort study at the Royal Women's Hospital, Melbourne, Australia, including 471 histologically confirmed endometriosis patients. Statistical analyses included multivariate logistic regression and multivariate modelling, correcting for multiple testing. Outcomes were the presence or absence of surgically classified lesion phenotypes, as per revised American Society for Reproductive Medicine criteria including superficial or deep, peritoneal or ovarian, and adhesions (Study I); and lesions at specific anatomical locations (including pelvic side wall, uterosacral ligament, pouch of Douglas, ovarian, uterovesical fold, bladder, and pararectal endometriosis) (Study II).

RESULTS

In Study I, patients with higher BMI were more likely to have superficial peritoneal lesions (odds ratio [OR] 1.070, 95% confidence interval [CI] 1.004-1.144; P = 0.044), and less likely to have deep ovarian lesions (OR 0.928, 95% CI 0.864-0.993; P = 0.034). In Study II, patients with higher BMI were less likely to have uterovesical fold lesions (OR 0.927, 95% CI 0.867-0.985; P = 0.021) or anterior compartment lesions (OR 0.940, 95% CI 0.888-0.989; P = 0.023). After correcting for multiple testing, the relationship between BMI and lesion phenotypes did not persist (P > 0.01).

CONCLUSIONS

This analysis does not conclusively support an influence of BMI on endometriotic lesion phenotype based on surgical classification or location. Further investigation of the physiological disturbances underlying BMI and the promotion of endometriotic lesion phenotypes and their location is warranted, but any effect is likely to be small.

Activation of Hypocretin Neurons in Endometriosis

Endometriosis is a gynecological disease affecting 6-10% of women of reproductive age. In addition to gynecologic symptoms, endometriosis is associated with various systemic effects, including inflammation, altered body weight, and behavioral changes. Previous murine studies demonstrate that endometriosis is causally inked to increased pain sensitization, behavioral changes, and low body mass index (BMI). One possible cellular target that may mediate some of these findings is the hypocretin/orexin neurons. This neuronal system plays a role in regulating wakefulness/sleep cycles, pain perception, and appetite. We hypothesize that endometriosis alters activity level of the hypocretin/orexin (Hcrt) neuronal system. Mice underwent endometriosis induction surgeries (endo) or sham surgeries (sham) for the development of the experimental model. Immunocytochemistry was performed on harvested samples from the lateral hypothalamus, and activation levels of Hcrt cells were examined by quantifying the expression of phosphorylation of cAMP-responsive element binding protein (CREB) in these cells after an acute stress in sham and endo mice. Mice with endometriosis had greater Hcrt neurons activation than sham mice. Mice with endometriosis fed with high fat diet showed a lower fat/body weight and fat/lean tissue ratio compared to mice without endometriosis. There was no significant difference in food intake between sham and endometriosis mice. These results demonstrate that endometriosis is associated with low body mass and increased hypocretin/orexin activity, which could be implicated in the behavioral changes and to differences in body composition.

Endometriosis in adolescent and young women

Endometriosis in adolescence represents a specific variant of the disease with its own characteristics and, in some cases, even a possibly different pathogenesis. It has its own clinical presentation, diagnostic and therapeutic modalities. The condition is not rare as once thought and certainly deserves attention in view of increasing evidence of its likely progressive nature. Numerous theories for Its pathogenesis have been formulated and they have been divided into two main categories: the 'in-situ' and the 'transplantation' hypotheses. Clinical manifestations include as the prevailing symptom a persistent chronic pelvic pain, despite medical treatment, manifested under various forms: dysmenorrhea, acyclic chronic pain, acute abdominal pain and migraines. These symptoms can substantially affect the quality of life on an adolescent. At histopathology, adolescent endometriosis is characterized by a high proportion of subtle, clear, red or vesicular implants and by the rarity of deep nodules. Frequently, the picture includes ovarian endometriomas. In some adolescent girls, lesions may regress or even disappear, probably through immune suppression; in others, chronic stress, unhealthy diet or lifestyle such as high-fat diet, may accelerate lesional progression and cause symptoms. Classically, management of adolescent endometriosis has been centered on attempts to treat dysmenorrhea; today both medical and surgical modalities have the potential to improve quality of life, alleviate symptoms, prevent the development of more severe disease and minimize risks for future fertility in adolescents. Nonetheless, at present, medical treatments are considered the first line of interventions in treating young women.

Body size during adulthood, but not in childhood, associates with endometriosis, specifically in the peritoneal subtype-population-based life-course data from birth to late fertile age

INTRODUCTION

Endometriosis is a common gynecological condition causing chronic pain and infertility. Only limited data exist on body size during childhood and adolescence in affected women. A leaner body shape has been associated with endometriosis in adults. However, longitudinal follow-up data from birth to adulthood are lacking. The aim of this study was to assess the association between body size and endometriosis from birth to age 46 years. We also performed in-depth analysis of the endometriosis subtypes.

MATERIAL AND METHODS

This was a population-based study including 96% of the children born in Northern Finland in 1966. Endometriosis case identification was based on (a) the World Health Organization's International Statistical Classification of Diseases code documentation from national hospital discharge registers and (b) self-reported diagnosis. A total of 348 women with endometriosis (203 in subtype analysis) and 3487 women without endometriosis were identified. Pregnancy, birth, and growth data up to adolescence were collected from welfare clinical records. Follow-up data of the Northern Finland Birth Cohort 1966 were collected at ages 14, 31, and 46 years through postal questionnaires and clinical examinations and included height, weight, and waist and hip circumference measurements. The associations between endometriosis and body size were assessed using logistic regression models.

RESULTS

Body sizes in childhood and adolescence were comparable between women developing endometriosis and those not developing endometriosis. On average, the risk for endometriosis was 2% lower for every kilogram of weight (odds ratio [OR] 0.98, 95% CI 0.97-1.00) and 6% lower for every body mass index unit (OR 0.94, 95% CI 0.90-0.99) at age 31. By age 46, a lower risk for peritoneal endometriosis was observed with greater weight (OR 0.95, 95% CI 0.92-0.98), weight gain from age 14 to age 46 years (OR 0.97, 95% CI 0.93-1.00), body mass index (OR 0.90, 95% CI 0.82-0.98), waist circumference (OR 0.95, 95% CI 0.92-0.99), and waist-hip ratio (OR 0.41, 95% CI 0.21-0.78).

CONCLUSIONS

This study provides further evidence of the associations between endometriosis and body size and adiposity, specifically in women with peritoneal endometriosis. The associations are evident in adulthood but not in childhood or adolescence.

Early life factors for endometriosis: a systematic review

BACKGROUND

Despite its high prevalence and health burden, many aspects of endometriosis remain unclear, including risk factors and the underlying biological mechanisms. Exposures during early life, including in utero, are thought to play an important role in the subsequent onset of the condition. To date, however, much of the evidence from studies on early life exposures and diagnosed endometriosis appears mixed and difficult to assess.

OBJECTIVE AND RATIONALE

This study aims to provide a systematic review of the epidemiologic evidence on early life factors associated with the subsequent diagnosis of endometriosis. In utero and early life exposures have previously been linked to a range of adult health outcomes, including infertility.

SEARCH METHODS

A systematic review of case-control, cross-sectional and cohort studies was conducted using the search terms 'endometriosis'[MeSH] AND ('risk factors'[MeSH] OR 'protective factors'[MeSH]) AND ('in utero', 'fetal', 'neonatal, 'perinatal', 'developmental origins', 'early life', 'childhood' OR 'life course') in Embase, PubMed and Scopus databases. The review included articles published in English until 10 June 2018 with original data from studies with diagnosed endometriosis. The quality of primary studies was evaluated using the Newcastle-Ottawa Scale by both authors independently. Due to the degree of inconsistency in the measurements and study methods, a qualitative assessment of findings was undertaken rather than meta-analysis.

OUTCOMES

The search retrieved 70 records without duplicates that contained 20 records on human case-control, cross-sectional or cohort studies, from which 11 papers/studies were selected based on their assessment score. The majority of studies found that women born with low birthweight (<2.5 kg or <5.5 lb) were more likely to be diagnosed with endometriosis. For other early life factors, the evidence is mixed or limited, with further research needed on the association of endometriosis with preterm birth, in utero exposure to diethylstilbestrol and to maternal smoking, passive smoking in early life, and infant formula feeding (compared with breastfeeding).

WIDER IMPLICATIONS

While the weight of evidence points to low birthweight as a risk factor for diagnosis of endometriosis, future research is warranted on this and other key early life exposures where the findings are mixed to provide more robust evidence and for insights on potential causal pathways. Such research, however, needs to address current methodological issues, such as the use of prospective data from large population-based studies, better diagnostic methods to confirm disease free status, more consistent definitions of variables and consideration of potential biological mechanisms to guide the analyses. The improvements will advance the future synthesis of evidence to support clinically relevant risk assessment for a more timely diagnosis and treatment of endometriosis.

Is body mass index associated with the incidence of endometriosis and the severity of dysmenorrhoea: a case-control study in China?

OBJECTIVE

Endometriosis is considered as a serious gynaecological disease in women at a reproductive age. Lower body mass index (BMI) is thought to be a risk factor. However, recent studies indicated that women with normal BMI were also more likely to develop endometriosis, suggesting the association with BMI is controversial. We therefore investigated the association of BMI and surgically diagnosed endometriosis in a cohort of Chinese women.

DESIGN

Retrospective case-control study.

SETTING

Tertiary hospital.

PATIENTS

709 women with endometriosis and 807 age matched controls between January 2018 and August 2019.

INTERVENTION

Age at diagnosis, parity, gravida, BMI and self-reported dysmenorrhoea status were collected and the association of BMI and endometriosis was analysed.

MEASUREMENT AND MAIN RESULTS

Overall, the median BMI was not different between patients and controls (21.1 kg/m² vs 20.9 kg/m², p=0.223). According to the BMI categories for Asians/Chinese by WHO (underweight: <18.5 kg/m², normal weight: 18.5-22.99 kg/m², overweight: 23-27.49 kg/m², obese: ≥27.50 kg/m²), overall, there was no difference in the association of BMI and endometriosis (p=0.112). 60% of patients were of normal weight. However, the OR of obese patients (BMI over 27.50 kg/m²) having endometriosis was1.979 (95% CI 1.15 to 3.52, p=0.0185), compared with women with normal weight. 50.3% patients reported dysmenorrhoea, and the OR of developing severe dysmenorrhoea in obese patients (BMI over 27.50 kg/m²) was 3.64 (95% CI 1.195 to 10.15, p=0.025), compared with patients with normal weight.

CONCLUSION

Our data demonstrate that overall there was no association between BMI and the incidence of endometriosis, but there was a significant increase in the incidence of endometriosis in obese women, compared with women with normal weight. Obesity was also a risk factor for severe dysmenorrhoea.

Feasibility and safety of laparoscopic approach in obese patients with endometriosis: a multivariable regression analysis

PURPOSE

To evaluate the feasibility and safety of laparoscopic excision of endometriotic lesions in obese women.

METHODS

Retrospective analysis of prospectively collected data involving consecutive women scheduled for complete laparoscopic removal of macroscopic endometriotic lesions between January 2012 and November 2018. Operative time, laparotomic conversion rates, complication rates, and length of hospital stay were recorded.

RESULTS

One thousand two hundred thirty women were enrolled and divided into two main groups, according to the World Health Organization classification of obesity, obese (body mass index ≥ 30 kg/m²) and non-obese (body mass index < 30 kg/m²). During the study period, 91 (7.4% of overall study cohort) obese women underwent surgery. At univariate analyses, significant differences between the two groups were found in terms of age, rates of severe endometriosis, American Society of Anesthesiologists physical status classification ≥ III, and different surgical procedures. Significant differences in terms of median operative time [125 (interquartile range (IQR) 85-165) in obese group vs 110 min (IQR 75-155) in non-obese group, P = 0.04] were observed. There were no significant differences between the obese and non-obese groups with respect to the other variables of interest. After adjusted multivariable regression models for potential confounders, difference in operating time (coefficient of 13.389; 95% CI 1.716, 25.060) was still found to be significant.

CONCLUSION

In our tertiary care referral center, laparoscopic removal of endometriosis is feasible and safe, except for a slight increase of operative time and conversion rate.

Birth weight, childhood body mass index and height and risks of endometriosis and adenomyosis

Background: Body size in adult life is likely associated with risks of endometriosis and adenomyosis, yet little is known about associations with body size earlier in life.Aim: To examine whether birth weight, childhood body mass index (BMI) and height are associated with risks of endometriosis and adenomyosis.Subjects and methods: From the Copenhagen School Health Records Register, 171,447 girls born 1930-1996, with measured weights and heights at ages 7-13 were included. Outcomes were obtained from health registers. Cox regressions were performed to estimate hazard ratios (HR) and 95% confidence intervals (CI).Results: During follow-up, 2149 endometriosis cases and 1410 adenomyosis cases were diagnosed. Childhood BMI was inversely associated with endometriosis (HR = 0.92 [95% CI: 0.88-0.96] per z-score at age 7). In contrast, childhood height was positively associated with endometriosis (HR = 1.09 [95% CI: 1.05-1.14] per z-score at age 7). Associations with childhood body size did not differ by endometriosis location. Childhood BMI and height had limited associations with adenomyosis. Birth weight was not associated with endometriosis or adenomyosis.Conclusion: Lean and tall girls are more often diagnosed with endometriosis, but not adenomyosis. These findings suggest that indicators of endometriosis risk are already apparent at early ages.

Is Stress a Cause or a Consequence of Endometriosis?

Clinical studies clearly indicate that endometriosis is a condition associated with high levels of chronic stress. The stress intensity correlates with pain severity and disease extension. However, it is unknown whether chronic stress represents a primary cause of endometriosis and, therefore, if avoiding or treating chronic stress may reduce the risk of developing endometriosis. Repeated, uncontrolled stress either before or after experimental endometriosis induction promotes disease mechanisms and accelerates lesion growth in rodents. Furthermore, patients with endometriosis have a heightened risk of other inflammatory and immune-related diseases, many of which have also been associated with stress. Here, we review the latest evidences regarding the relationship between chronic stress and endometriosis and discuss the potential bidirectional aspect of such association. Further research may clarify if endometriosis is a cause and/or a consequence of stress and whether stress-reducing therapies are effective to mitigate symptoms and slow down the development of endometriotic lesions.

Evaluation of lifestyle and endometriosis in infertile women referring to the selected hospital of Tehran University Medical Sciences

Background and Aim

Endometriosis is a chronic and common disease in the world in which living endometrium stroma and glands are found outside the uterus. The presence of this tissue in different parts of the body causes various symptoms that have an adverse effect on women's quality of life, fertility rate, and productivity. The aim of this study was to determine the relationship between lifestyle and endometriosis in infertile women referred to the selected hospital of Tehran University of Medical Sciences.

Materials and Methods

The nature of this study is descriptive-comparative. The convenient sampling method is used among all infertile women undergoing laparoscopy, in group 1 (with endometriosis diagnosis) and group 2 (without endometriosis). The sample size is estimated to be 125 in each group according to the Cochran formula and with the alpha coefficient of 0.05. Data analysis was done using SPSS software version 20.

Results

There was a direct and significant relationship between the probability of developing endometriosis and age, education level, and regularity of menstruation variables so that with the increase in each of the above variables, the probability of the disease increases. There was a significant and inverse association between the incidence of endometriosis and the body mass index (BMI) variable, which means that with the increase in this variable, the risk of endometriosis in individuals is reduced.

Conclusion

This study suggests that high age, low BMI, menstrual cycle regularity, and education have a strong relationship with endometriosis in infertile women, and there was no relationship between lifestyle and the incidence of endometriosis among them.

Rethinking mechanisms, diagnosis and management of endometriosis

Endometriosis is a chronic inflammatory disease defined as the presence of endometrial tissue outside the uterus, which causes pelvic pain and infertility. This disease should be viewed as a public health problem with a major effect on the quality of life of women as well as being a substantial economic burden. In light of the considerable progress with diagnostic imaging (for example, transvaginal ultrasound and MRI), exploratory laparoscopy should no longer be used to diagnose endometriotic lesions. Instead, diagnosis of endometriosis should be based on a structured process involving the combination of patient interviews, clinical examination and imaging. Notably, a diagnosis of endometriosis often leads to immediate surgery. Therefore, rethinking the diagnosis and management of endometriosis is warranted. Instead of assessing endometriosis on the day of the diagnosis, gynaecologists should consider the patient's 'endometriosis life'. Medical treatment is the first-line therapeutic option for patients with pelvic pain and no desire for immediate pregnancy. In women with infertility, careful consideration should be made regarding whether to provide assisted reproductive technologies prior to performing endometriosis surgery. Modern endometriosis management should be individualized with a patient-centred, multi-modal and interdisciplinary integrated approach.

The association between body mass index and the risk of endometriosis: A meta-analysis

Background:

Many epidemiologic studies have been conducted to assess factors that were associated to endometriosis, but there is no consistency in results. Therefore, we conducted this meta-analysis to investigate the association between body mass index and the risk of endometriosis.

Methods:

In this meta-analysis, relevant studies that published in major international electronic bibliographic databases of PubMed, Scopus and Web of Science were systematically searched during November 2017. The Begg and Egger’s test was used to investigate publication bias in included studies. The Q-statistic and I2 tests were carried out for measuring heterogeneity. The random-effects model was conducted to obtain pooled odds ratio.

Results:

Our results showed a direct association between underweight and endometriosis in woman (odds ratio = 1.41, 95% confidence interval = 1.16–1.66), so underweight woman had 41% higher chance for endometriosis. However, we did not find linear association between overweight and endometriosis (odds ratio = 0.95; 95% confidence interval: 0.72–1.18) and obesity and endometriosis (odds ratio = 0.88; 95% confidence interval: 0.54–1.21), respectively.

Conclusions:

Our results suggested that underweight was a risk factor for the endometriosis, while overweight and obesity were not protective factors for endometriosis.

Characteristics of endometriosis: A case-cohort study showing elevated IgG titers against the TSH receptor (TRAb) and mental comorbidity

OBJECTIVES

Endometriosis has been associated with a wide range of factors. The disease share immunological features with autoimmune diseases, and the prevalence of both hypo- and hyperthyroidism has been reported to be increased. However, the associations have to be confirmed and the mechanisms explored. The aim of this observational study was to investigate socioeconomic factors, lifestyle habits, and somatic and mental comorbidities in endometriosis compared to the general population.

STUDY DESIGN

In all, 172 women with endometriosis completed a study questionnaire and were interviewed regarding socioeconomic factors, lifestyle habits, psychological well-being, and medical history. Bowel symptoms were measured by the Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS). Serum was analyzed for IgG levels of TSH receptor antibodies (TRAb) and anti-thyroid peroxidase (TPO) antibodies. Women from the general population served as controls. Differences were calculated by logistic regression, adjusted for confounders.

RESULTS

Alcohol intake, leisure time physical activity, body mass index and asthma were inversely, whereas IBS was positively associated with endometriosis. Hypothyroidism and anti-TPO antibodies did not associate, but elevated TRAb antibody titers were associated with endometriosis (odds ratio (OR): 539.26; 95% confidence interval (CI): 114.29-2544.32 for highest versus lowest tertile; p for trend < 0.001). Impaired psychological well-being (p for trend = 0.003) and current intake of antidepressant medication (OR: 3.54; 95% CI: 1.22-10.28; p = 0.020) associated with endometriosis, and impaired psychological well-being correlated with all gastrointestinal symptoms measured (all p < 0.001).

CONCLUSIONS

Lifestyle habits and asthma are inversely associated, and IBS and impaired psychological well-being are positively associated with endometriosis. TRAb titers are associated with endometriosis, supporting a link between endometriosis, autoimmunity and thyroid pathophysiology, although overt thyroid diseases do not associate.

Clinical evaluation and management of endometriosis: guideline for Korean patients from Korean Society of Endometriosis

Endometriosis is one of the most common diseases in reproductive ages, and it affects patients' quality of life and fertility. However, few Korean guidelines are available for the evaluation and management of endometriosis. Korean Society of Endometriosis reviewed various literatures and trials, and to provide seventy-one evidence-based recommendations. This review presents guidelines for the diagnosis and management of endometriosis with emphasis on: it's role in infertility, treatment of recurrence, asymptomatic women, endometriosis in adolescents and menopausal women, and possible association of endometriosis with cancer.

A prospective cohort study of meat and fish consumption and endometriosis risk

BACKGROUND

Only 2 case-control studies have examined the associations between consumption of meat products and endometriosis risk with inconsistent results. Consumption of animal products has the potential to influence endometriosis risk through effects on steroid hormones levels.

OBJECTIVE

We sought to determine whether higher intake of red meat, poultry, fish, and seafood are associated with risk of laparoscopically confirmed endometriosis.

STUDY DESIGN

A total of 81,908 participants of the prospective Nurses' Health Study II were followed up from 1991 through 2013. Diet was assessed via food frequency questionnaire every 4 years. Cox proportional hazards models were used to calculate rate ratios and 95% confidence intervals.

RESULTS

During 1,019,294 person-years of follow-up, 3800 cases of incident laparoscopically confirmed endometriosis were reported. Women consuming >2 servings/d of red meat had a 56% higher risk of endometriosis (95% confidence interval, 1.22-1.99; P_trend < .0001) compared to those consuming ≤1 serving/wk. This association was strongest for nonprocessed red meats (rate ratio, 1.57; 95% confidence interval, 1.35-1.83 for ≥2 servings/d vs ≤1 servings/wk; P_trend < .0001), particularly among women who had not reported infertility (P_interaction = .0004). Women in the highest category of processed red meat intake also had a higher risk of endometriosis (rate ratio, 1.20; 95% confidence interval, 1.06-1.37 for ≥5 servings/wk vs <1 serving/mo; P_trend = .02). Intakes of poultry, fish, shellfish, and eggs were unrelated to endometriosis risk.

CONCLUSION

Our prospective analysis among premenopausal US nurses suggests that red meat consumption may be an important modifiable risk factor for endometriosis, particularly among women with endometriosis who had not reported infertility and thus were more likely to present with pain symptoms. Well-designed dietary intervention studies among women with endometriosis could help confirm this observation.

SULFATION PATHWAYS: Contribution of intracrine oestrogens to the aetiology of endometriosis

Endometriosis is an incurable hormone-dependent inflammatory disease that causes chronic pelvic pain and infertility characterized by implantation and growth of endometrial tissue outside the uterine cavity. Symptoms have a major impact on the quality of life of patients resulting in socioeconomic, physical and psychological burdens. Although the immune system and environmental factors may play a role in the aetiology of endometriosis, oestrogen dependency is still considered a hallmark of the disorder. The impact of oestrogens such as oestrone and particularly, oestradiol, on the endometrium or endometriotic lesions may be mediated by steroids originating from ovarian steroidogenesis or local intra-tissue production (intracrinology) dependent upon the expression and activity of enzymes that regulate oestrogen biosynthesis and metabolism. Two key pathways have been implicated: while there is contradictory data on the participation of the aromatase enzyme (encoded by CYP19A1), there is increasing evidence that the steroid sulphatase pathway plays a role in both the aetiology and pathology of endometriosis. In this review, we consider the evidence related to the pathways leading to oestrogen accumulation in endometriotic lesions and how this might inform the development of new therapeutic strategies to treat endometriosis without causing the undesirable side effects of current regimes that suppress ovarian hormone production.

Risk for and consequences of endometriosis: A critical epidemiologic review

Endometriosis affects approximately 10% of women of reproductive age. Characteristics robustly associated with a greater risk for endometriosis include early age at menarche, short menstrual cycle length, and lean body size, whereas greater parity has been associated with a lower risk. Relationships with other potential characteristics including physical activity, dietary factors, and lactation have been less consistent, partially because of the need for rigorous data collection and a longitudinal study design. Critical methodologic complexities include the need for a clear case definition; valid selection of comparison/control groups; and consideration of diagnostic bias and reverse causation when exploring demographic characteristics, medical history, and lifestyle factors. Reviewers and editors must demand a detailed description of rigorous methods to facilitate comparison and replication to advance our understanding of endometriosis.

The association of body mass index with endometriosis and disease severity in women with pain

Introduction:

There is a well-established inverse relationship between body mass index and frequency of endometriosis. However, these population-based studies have relied mostly on self-reported cases of endometriosis, rather than surgically confirmed endometriosis where disease severity has been objectively assessed. The aim of the current retrospective study was to establish whether the established relationship between endometriosis and low body mass index was independent of disease severity.

Methods:

Women with menstrual and/or pelvic pain undergoing laparoscopy for suspected endometriosis were recruited for this retrospective study (n = 509). Women were grouped by body mass index (kg/m2) according to World Health Organization criteria: underweight (<18.5), normal (18.5–24.99), pre-obese (25–29.99) or obese (≥30). Endometriosis was scored according to the revised American Fertility Society system. Data were analysed based on body mass index and endometriosis status to identify any relationship between body mass index and disease.

Results:

The average body mass index of women with endometriosis was 25.0 kg/m2. The body mass index distribution of women with endometriosis differed relative to women in the general population. As expected, fewer obese women had endometriosis than in the lower body mass index categories. However, the obese women who did have endometriosis had significantly higher revised American Fertility Society scores compared to women with normal and pre-obese body mass indices.

Discussion:

Our results are consistent with the established finding of an inverse relationship between body mass index and endometriosis. The novel finding from this study is that obesity is associated with increased disease severity and reduced frequency of stage I endometriosis. It remains unclear what role body mass index has in the cause or effect of endometriosis; we speculate that body mass index may be useful for sub-classifying the disease.

Associations among body size across the life course, adult height and endometriosis

STUDY QUESTION

Are body size across the life course and adult height associated with endometriosis?

SUMMARY ANSWER

Endometriosis is associated with lean body size during childhood, adolescence and adulthood; tall total adult height; and tall sitting height.

WHAT IS KNOWN ALREADY

The literature suggests that both adult body size and height are associated with endometriosis risk, but few studies have investigated the role of body size across the life course. Additionally, no study has investigated the relationships between components of height and endometriosis.

STUDY DESIGN, SIZE, DURATION

We used a nested case-control design within E3N (Etude Epidémiologique auprès de femmes de l'Education Nationale), a prospective cohort of French women. Data were updated every 2-3 years through self-administered questionnaires. Odds ratios (ORs) and 95% CIs were computed using logistic regression models adjusted for a priori confounding factors.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 2416 endometriosis cases were reported as surgically ascertained among the 61 208 included women.

MAIN RESULTS AND THE ROLE OF CHANCE

The odds of endometriosis were lower among women who reported having a large versus lean body size at 8 years (P for trend = 0.003), at menarche (P for trend < 0.0001) and at ages 20-25 years (P for trend < 0.0001). Women in the highest quartiles of height had statistically significantly increased odds of endometriosis compared to those in the lowest (<158 cm) (162-164 cm: OR = 1.28, 95% CI = 1.12-1.46; ≥165 cm: OR = 1.33, 95% CI = 1.18-1.49, P for trend < 0.0001). Statistically significantly increased odds were also observed among women with a taller sitting height (OR = 1.24, 95% CI = 1.05-1.47, P for trend = 0.01). Leg length was not statistically significantly associated with endometriosis.

LIMITATIONS REASONS FOR CAUTION

Endometriosis cases may be prone to misclassification; however, we restricted our case definition to surgically-confirmed cases, which showed a high validation rate. Body size is based on retrospective self-report, which may be subject to recall bias.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this study suggest that endometriosis is positively associated with lean body size across the life course and total adult height. They also suggest that components of height are associated with endometriosis, which should be investigated further.

STUDY FUNDING/COMPETING INTEREST(S)

The Mutuelle Générale de l'Education Nationale (MGEN); the European Community; the French League against Cancer (LNCC); Gustave Roussy; the French Institute of Health and Medical Research (Inserm). L.V.F. was supported by a T32 grant (#HD060454) in reproductive, perinatal and pediatric epidemiology from the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Cancer Institute (3R25CA057711) National Institutes of Health. M.K. was supported by a Marie Curie Fellowship within the seventh European Community Framework Programme (#PIOF-GA-2011-302078). The authors have no conflicts of interest to declare.

Association between body mass index and endometriosis risk: a meta-analysis

Background

Epidemiological studies have sought to establish a relationship between a woman's current body mass index and endometriosis, but with varying results. This meta-analysis was to summarize the current epidemiological evidence.

Methods

Pertinent studies were identified by searching PubMed and Web of Science through November 2016. Study-specific risk estimates were combined using fixed or random effects models depending on whether significant heterogeneity was detected.

Results

A total of 11 studies (two cohort studies and nine case-control studies) was included in the meta-analysis. The pooled relative risk of endometriosis was 0.67 (95% CI: 0.53, 0.84) for each 5 kg/m² increase in current body mass index, with statistical significant heterogeneity across the studies (P <0.001, I² =86.9%). Compared with normal weight women, the pooled relative risk for obese women was 0.89 (95% CI: 0.83, 0.96), which was lower than that for overweight women (relative risk =0.97; 95% CI: 0.91, 1.05). The combined estimate was robust across subgroup and sensitivity analyses and no observed publication bias was detected.

Conclusion

This study suggested that higher body mass index may be associated with lower risk of endometriosis. Further work will need to focus on elucidating underlying biologic mechanism that contribute to the initiation of endometriosis.

Height and Body Size in Childhood, Adolescence, and Young Adulthood and Breast Cancer Risk According to Molecular Subtype in the Nurses' Health Studies

Height and body size in childhood and young adulthood have been consistently associated with breast cancer risk; whether associations differ across molecular subtypes is unclear. In a pooled analysis of the Nurses' Health Studies, we prospectively examined the association of four exposures: height, body mass index (BMI) at the age of 18 years, childhood and adolescent somatotypes, with breast cancer risk according to molecular subtypes defined by immunohistochemical markers. We used multivariable-adjusted Cox proportional hazards regression to estimate HRs and 95% confidence intervals (CI). We identified 2,983 luminal A, 1,281 luminal B, 318 HER2-enriched, 408 basal-like, and 128 unclassified tumors. Height was positively associated with all subtypes (Pheterogeneity = 0.78). BMI at the age of 18 (Pheterogeneity = 0.001), childhood (Pheterogeneity = 0.51), and adolescent somatotype (Pheterogeneity = 0.046) were inversely associated, but with differences in magnitude of association. BMI at the age of 18 of ≥25 kg/m(2) (compared with 20-21.9 kg/m(2)) was associated with a 52% decreased risk of HER2-enriched (HR, 0.48; 95% CI, 0.26-0.91; Ptrend < 0.0001) and 39% reduced risk of basal-like tumors (HR, 0.61; 95% CI, 0.36-1.02; Ptrend = 0.008). Compared with the lowest category, women in the highest adolescent body size category were 71% less likely to develop HER2-enriched (HR, 0.29; 95% CI, 0.10-0.85; Ptrend = 0.0005) and 60% less likely to develop basal-like (HR, 0.40; 95% CI, 0.17-0.95; Ptrend = 0.0008). Height was positively associated with risk of all breast cancer molecular subtypes. BMI at 18 years and childhood and adolescent were inversely associated with risk of most breast cancer molecular subtypes with somewhat stronger associations with HER2-enriched and basal-like subtypes. Cancer Prev Res; 9(9); 732-8. ©2016 AACR.

Progress in the diagnosis and management of adolescent endometriosis: an opinion

Increasing evidence indicates that early onset endometriosis (EOE), starting around menarche or early adolescence, may have an origin different from the adult variant, originating from neonatal uterine bleeding (NUB). This implies seeding of naïve endometrial progenitor cells into the pelvic cavity with NUB; these can then activate around thelarche. It has its own pathophysiology, symptomatology and risk factors, warranting critical management re-evaluation. It can also be progressive, endangering future reproductive capacity. This variant seems to be characterized by the presence of ovarian endometrioma. Today, the diagnosis of endometriosis in young patients is often delayed for years; if rapidly progressive, it can severely affect pelvic organs, even in the absence of serious symptoms. Given the predicament, great attention must be paid to symptomatology that is often non-specific, justifying a search for new, simple, non-invasive markers of increased risk. Better use of modern imaging techniques will aid considerably in screening for the presence of EOE. Traditional laparoscopy should be limited to cases in which imaging gives rise to suspicion of severity and a stepwise, minimally invasive approach should be used, followed by medical treatment to prevent recurrence. In conclusion, EOE represents a condition necessitating early diagnosis and stepwise management, including medical treatment.

A higher prevalence of endometriosis among Asian women does not contribute to poorer IVF outcomes

PURPOSE

The purpose of the study was to determine whether diagnosis of endometriosis or endometriosis with endometrioma influences in vitro fertilization (IVF) outcomes in an ethnically diverse population.

METHODS

Women undergoing a first IVF cycle (n = 717) between January 1, 2008 and December 31, 2009, at a university-affiliated infertility clinic, were retrospectively assessed for an endometriosis diagnosis. Differences in prevalence of endometriosis by ethnicity were determined, as well as differences in IVF success by ethnicity, with a focus on country of origin for Asian women. A multivariate model was generated to assess the relative contributions of country of origin and endometriosis to chance of clinical pregnancy with IVF.

RESULTS

Endometriosis was diagnosed in 9.5% of participants; 3.5% also received a diagnosis of endometrioma. Endometriosis prevalence in Asian women was significantly greater than in Caucasians (15.7 vs. 5.8%, p < 0.01). Women of Filipino (p < 0.01), Indian (p < 0.01), Japanese (p < 0.01), and Korean (p < 0.05) origin specifically were more likely to have endometriosis than Caucasian women, although there was no difference in endometrioma presence by race/ethnicity. Oocyte quantity, embryo quality, and fertilization rates did not relate to endometriosis. Clinical pregnancy rates were significantly lower for Asian women, specifically in Indian (p < 0.05), Japanese (p < 0.05), and Korean (p < 0.05) women, compared to Caucasian women, even after controlling for endometriosis status.

CONCLUSIONS

The prevalence of endometriosis appears to be higher in Filipino, Indian, Japanese, and Korean women presenting for IVF treatment than for Caucasian women; however, the discrepancy in IVF outcomes was conditionally independent of the presence of endometriosis. Future research should focus on improving pregnancy outcomes for Asian populations whether or not they are affected by endometriosis, specifically in the form of longitudinal studies where exposures can be captured prior to endometriosis diagnoses and infertility treatment.

Beyond Body Mass Index: Using Anthropometric Measures and Body Composition Indicators to Assess Odds of an Endometriosis Diagnosis

BACKGROUND

Body mass index (BMI) and endometriosis have been inversely associated. To address gaps in this research, we examined associations among body composition, endometriosis, and physical activity.

MATERIALS AND METHODS

Women from 14 clinical sites in the Salt Lake City, Utah and San Francisco, California areas and scheduled for laparoscopy/laparotomy were recruited during 2007-2009. Participants (N = 473) underwent standardized anthropometric assessments to estimate body composition before surgery. Using a cross-sectional design, odds of an endometriosis diagnosis (adjusted odds ratio [aOR]; 95% confidence interval [CI]) were calculated for anthropometric and body composition measures (weight in kg; height in cm; mid upper arm, waist, hip, and chest circumferences in cm; subscapular, suprailiac, and triceps skinfold thicknesses in mm; arm muscle and fat areas in cm²; centripetal fat, chest-to-waist, chest-to-hip, waist-to-hip, and waist-to-height ratios; arm fat index; and BMI in kg/m²). Physical activity (metabolic equivalent of task-minutes/week) and sedentariness (average minutes sitting on a weekday) were assessed using the International Physical Activity Questionnaire-Short Form. Measures were modeled continuously and in quartiles based on sample estimates. Adjusted models were controlled for age (years, continuous), site (Utah/California), smoking history (never, former, or current smoker), and income (below, within 180%, and above of the poverty line). Findings were standardized by dividing variables by their respective standard deviations. We used adjusted models to examine whether odds of an endometriosis diagnosis were moderated by physical activity or sedentariness.

RESULTS

Inverse relationships were observed between endometriosis and standardized: weight (aOR = 0.71, 95% CI 0.57-0.88); subscapular skinfold thickness (aOR = 0.79, 95% CI 0.65-0.98); waist and hip circumferences (aOR = 0.79, 95% CI 0.64-0.98 and aOR = 0.76, 95% CI 0.61-0.94, respectively); total upper arm and upper arm muscle areas (aOR = 0.76, 95% CI 0.61-0.94 and aOR = 0.74, 95% CI 0.59-0.93, respectively); and BMI (aOR = 0.75, 95% CI 0.60-0.93), despite similar heights. Women in the highest versus lowest quartile had lower adjusted odds of an endometriosis diagnosis for: weight; mid-upper arm, hip, and waist circumferences; total upper arm and upper arm muscle areas; BMI; and centripetal fat ratio. There was no evidence of a main effect or moderation of physical activity or sedentariness.

CONCLUSION

In a surgical cohort, endometriosis was inversely associated with anthropometric measures and body composition indicators.

Trauma and endometriosis. A review. May we explain surgical phenotypes and natural history of the disease?

OBJECTIVE

The study was performed to evaluate whether trauma is an initial event of development of endometriosis.

METHOD

Using Medline database from January 1960 up to December 2014, a systematic review was made of all published studies using the keywords trauma, healing, injury, infection, hyperperistaltism, stretch and endometriosis, adenomyosis and trauma. Studies and review articles written in French and/or in English related to the topic were included and reviewed independently by two authors.

RESULTS

The role of trauma is well-established for endometriotic lesions diagnosed in surgical scars. Various traumas including delivery, uterine curettage or incision, intraperitoneal hemorrhage, or occult pelvic inflammatory diseases could be involved to explain other localizations of the disease. Many data suggested that the healing process, particularly growth factors and the associated estrogen production, may facilitate the implantation and the growth of ectopic endometrial cells. After the initial, a traumatic event, the phenotype of the disease would depend on the tissue in which the endometriotic lesion grows.

CONCLUSIONS

The present literature review may support a potential role of a trauma as an initial event of endometriosis.

Endometriosis: Epidemiology, Diagnosis and Clinical Management

Purpose of review

Endometriosis is a disease of adolescents and reproductive-aged women characterized by the presence of endometrial tissue outside the uterine cavity and commonly associated with chronic pelvic pain and infertility. Here we review the epidemiology of endometriosis as well as potential biomarkers for detection and with the goal of highlighting risk factors that could be used in combination with biomarkers to identify and treat women with endometriosis earlier..

Recent findings

Early age at menarche, shorter menstrual length, and taller height are associated with a higher risk of endometriosis while parity, higher body mass index (BMI) and smoking are associated with decreased risk. Endometriosis often presents as infertility or continued pelvic pain despite treatment with analgesics and cyclic oral contraceptive pills.

Summary

Despite a range of symptoms, diagnosis of endometriosis is often delayed due to lack of non-invasive, definitive and consistent biomarkers for diagnosis of endometriosis. Hormone therapy and analgesics are used for treatment of symptomatic endometriosis. However, the efficacy of these treatments are limited as endometriosis often recurs. In this review, we describe potential diagnostic biomarkers and risk factors that may be used as early non-invasive in vitro tools for identification of endometriosis to minimize diagnostic delay and improve reproductive health of patients.

Low Body Mass Index in Endometriosis Is Promoted by Hepatic Metabolic Gene Dysregulation in Mice

The gynecological disease endometriosis is characterized by the deposition and proliferation of endometrial cells outside the uterus and clinically is linked to low body mass index (BMI). Gene expression in the liver of these women has not been reported. We hypothesized that endometriosis may impact hepatic gene expression, promoting a low BMI. To determine the effect of endometriosis on liver gene expression, we induced endometriosis in female mice by suturing donor mouse endometrium into the peritoneal cavity and measuring the weight of these mice. Dual-energy X-ray absorptiometry (DEXA) scanning of these mice showed lower body weight and lower total body fat than controls. Microarray analysis identified 26 genes differentially regulated in the livers of mice with endometriosis. Six of 26 genes were involved in metabolism. Four of six genes were upregulated and were related to weight loss, whereas two genes were downregulated and linked to obesity. Expression levels of Cyp2r1, Fabp4, Mrc1, and Rock2 were increased, whereas Igfbp1 and Mmd2 expression levels were decreased. Lep and Pparg, key metabolic genes in the pathways of the six genes identified from the microarray, were also upregulated. This dysregulation was specific to metabolic pathways. Here we demonstrate that endometriosis causes reduced body weight and body fat and disrupts expression of liver genes. We suggest that altered metabolism mediated by the liver contributes to the clinically observed low BMI that is characteristic of women with endometriosis. These findings reveal the systemic and multiorgan nature of endometriosis.

Women's Reproductive History Before the Diagnosis of Incident Endometriosis

BACKGROUND

Endometriosis is a gynecologic disease reported to be associated with infertility and, possibly, adverse pregnancy outcomes. While considerable research focuses on pregnancy outcomes following diagnosis and/or treatment, few data actually describe women's reproductive history before diagnosis for a more complete understanding of endometriosis and reproduction.

MATERIALS AND METHODS

The study sample comprised 473 women (aged 18-44 years) undergoing laparoscopies or laparotomies, irrespective of surgical indication at 14 clinical sites, during the period 2007-2009. Upon enrollment and before surgery, women were queried about pregnancy intentions and the time required to become pregnant for planned pregnancies. Endometriosis was defined as surgically visualized disease. Using discrete time survival analysis, we estimated fecundability odds ratios (FORs) and 95% confidence intervals (CIs) to assess time to pregnancy (TTP) after adjusting for potential confounders (age, body composition, cigarette smoking, site). Generalized estimating equations accounted for multiple pregnancy attempts per woman. FORs <1.0 denote a longer TTP or diminished fecundity.

RESULTS

Approximately 66% and 69% of women with and without endometriosis, respectively, reported having a planned pregnancy before surgery, respectively. After adjustment, an endometriosis diagnosis was associated with ≈29% reduction in fecundity or a longer TTP across all pregnancy-trying attempts (adjusted FOR = 0.71; 95% CI 0.46-1.10). While FORs were consistently <1.0, irrespective of endometriosis staging, CIs included 1.

CONCLUSIONS

Women with endometriosis had a longer TTP than unaffected women, irrespective of disease severity, although the findings did not achieve significance. Prior reproductive history may be informative for predicting fecundity and pregnancy outcomes following diagnosis/treatment.

Endometriosis and mammographic density measurements in the Nurses' Health Study II

PURPOSE

Endometriosis and mammographic density have been hypothesized to be influenced by sex steroid hormonal exposures in adolescence and early adulthood. We investigated the association between endometriosis and mammographic density, a consistent and independent risk factor for breast cancer.

METHODS

We conducted a cross-sectional analysis among 1,581 pre- and postmenopausal women not previously diagnosed with breast cancer in the Nurses' Health Study II cohort. We measured average percent mammographic density and absolute dense and non-dense breast area using a validated computer-assisted method. Multivariable linear regression was used to estimate the association between endometriosis and mammographic density among pre- and postmenopausal women separately.

RESULTS

Among premenopausal women, average percent mammographic density was 43.1 % among women with endometriosis (n = 91) and 40.5 % among women without endometriosis (n = 1,150). Endometriosis was not associated significantly with mammographic density among premenopausal (% difference = 2.00 percentage points 95 % CI -1.33, 5.33) or among postmenopausal women (% difference = -0.89 percentage points 95 % CI -5.10, 3.33). Among premenopausal women, there was heterogeneity by BMI at age 18 (p value = 0.003), with a suggested association among those who were lean at age 18 (BMI < 20.6 kg/m(2)) (% difference = 3.74 percentage points 95 % CI -0.29, 7.78).

CONCLUSION

Endometriosis was not found to be associated with overall measurements of mammographic density.

Altered levels of acylcarnitines, phosphatidylcholines, and sphingomyelins in peritoneal fluid from ovarian endometriosis patients

Endometriosis is a complex, polygenic, and estrogen-dependent disease that affects 6% to 10% of women of reproductive age, and 30% to 50% of women with infertility and/or pelvic pain. Surgical diagnosis of endometriosis is still the gold standard, as there are currently no diagnostic biomarkers available. Due to the invasive diagnostics, it can take up to 11 years before affected women are diagnosed and receive the appropriate treatment. We performed a targeted metabolomics study to search for potential semi-invasive biomarkers in peritoneal fluid from endometriosis patients. Our case-control study comprised 29 ovarian endometriosis patients and 36 healthy control women. The 148 metabolites included acylcarnitines, glycerophospholipids, and sphingolipids, which were quantified by electrospray ionization tandem mass spectrometry. The strength of association between the metabolites and the metabolite ratios and disease was assessed using crude and adjusted odds ratios. The best combination of biomarkers was then selected by performing step-wise logistic regression. Our analysis reveals significantly decreased concentrations of 10 metabolites, of carnitine and acylcarnitines (C0, C8:1, C6C4:1 DC, C10:1), phosphatidylcholines (PC aa C38:3, PC aa C38:4, PC aa C40:4, PC aa C40:5), and sphingomyelins (SM C16:1, SM C18:1), and 125 significantly altered metabolite ratios in patients versus control women. The best model includes two ratios: a carnitine to a phosphatidylcholine (C0/PC ae C36:0); and between two phosphatidylcholines (PC aa C30:0/PC ae C32:2). When adjusted for age, this provides sensitivity of 82.8% and specificity of 94.4%, with AUC of 0.944. Our study supports the importance of carnitine, phosphatidylcholine, and sphingomyelin metabolites in the pathophysiology of endometriosis, and confirms the potential for the combination of individual metabolite ratios to provide biomarkers for semi-invasive diagnostics.

Evaluation of Risk Factors Associated with Endometriosis in Infertile Women

BACKGROUND

Endometriosis affects women's physical and mental wellbeing. Symptoms include dyspareunia, dysmenorrhea, pelvic pain, and infertility. The purpose of this study is to assess the correlation between some relevant factors and symptoms and risk of an endometriosis diagnosis in infertile women.

MATERIALS AND METHODS

A retrospective study of 1282 surgical patients in an infertility Institute, Iran between 2011 and 2013 were evaluated by laparoscopy. Of these, there were 341 infertile women with endometriosis (cases) and 332 infertile women with a normal pelvis (comparison group). Chi-square and t tests were used to compare these two groups. Logistic regression was done to build a prediction model for an endometriosis diagnosis.

RESULTS

Gravidity [odds ratio (OR): 0.8, confidence interval (CI): 0.6-0.9, P=0.01], parity (OR: 0.7, CI: 0.6-0.9, P=0.01), family history of endometriosis (OR: 4.9, CI: 2.1-11.3, P<0.001), history of galactorrhea (OR: 2.3, CI: 1.5-3.5, P=0.01), history of pelvic surgery (OR: 1.9, CI: 1.3-2.7, P<0.001), and shorter menstrual cycle length (OR: 0.9, CI: 0.9-0.9, P=0.04) were associated with endometriosis. Duration of natural menstruation and age of menarche were not correlated with subsequent risk of endometriosis (P>0.05). Fatigue, diarrhea, constipation, dysmenorrhea, dyspareunia, pelvic pain and premenstrual spotting were more significant among late-stage endometriosis patients than in those with early-stage endometriosis and more prevalent among patients with endometriosis than that of the comparison group. In the logistic regression model, gravidity, family history of endometriosis, history of galactorrhea, history of pelvic surgery, dysmenorrhoea, pelvic pain, dysparaunia, premenstrual spotting, fatigue, and diarrhea were significantly associated with endometriosis. However, the number of pregnancies was negatively related to endometriosis.

CONCLUSION

Endometriosis is a considerable public health issue because it affects many women and is associated with the significant morbidity. In this study, we built a prediction model which can be used to predict the risk of endometriosis in infertile women.

Overall Adiposity, Adipose Tissue Distribution, and Endometriosis: A Systematic Review

BACKGROUND

Endometriosis has been associated with a lean body habitus. However, we do not understand whether endometriosis is also associated with other characteristics of adiposity, including adipose tissue distribution and amount of visceral adipose tissue (VAT; adipose tissue lining inner organs). Having these understandings may provide insights on how endometriosis develops-some of the physiological actions of adipose tissue differ depending on tissue amount and location and are related to proposed mechanisms of endometriosis development.

OBJECTIVES

The aim of this study was to review the literature regarding overall adiposity, adipose tissue distribution and/or VAT, and endometriosis.

METHODS

We reviewed and synthesized studies indexed in PubMed and/or Web of Science. We included studies that had one or more measures of overall adiposity, adipose tissue distribution, and/or VAT and women with and without endometriosis for comparison. We summarized the findings and commented on the methods used and potential sources of bias.

RESULTS

Of 366 identified publications, 19 (5.2%) were eligible. Two additional publications were identified from reference lists. Current research included measures of overall adiposity (e.g., body figure drawings) or adipose tissue distribution (e.g., waist-to-hip ratio), but not VAT. The weight of evidence indicated that endometriosis was associated with low overall adiposity and with a preponderance of adipose tissue distributed below the waist (peripheral).

DISCUSSION

Endometriosis may be associated with being lean or having peripherally distributed adipose tissue. Well-designed studies with various sampling frameworks and precise measures of adiposity and endometriosis are needed to confirm associations between adiposity measures and endometriosis and delineate potential etiological mechanisms underlying endometriosis.

Occupational risk factors for endometriosis in a cohort of flight attendants

OBJECTIVES

This study aimed to (i) compare odds of endometriosis in a cohort of flight attendants against a comparison group of teachers and (ii) investigate occupational risk factors for endometriosis among flight attendants.

METHODS

We included 1945 flight attendants and 236 teachers aged 18-45 years. Laparoscopically confirmed endometriosis was self-reported via telephone interview, and flight records were retrieved from airlines to obtain work schedules and assess exposures for flight attendants. We used proportional odds regression to estimate adjusted odds ratios (OR adj) and 95% confidence intervals (95% CI) for associations between exposures and endometriosis, adjusting for potential confounders.

RESULTS

Flight attendants and teachers were equally likely to report endometriosis (OR adj1.0, 95% CI 0.5-2.2). Among flight attendants, there were no clear trends between estimated cosmic radiation, circadian disruption, or ergonomic exposures and endometriosis. Greater number of flight segments (non-stop flights between two cities) per year was associated with endometriosis (OR adj2.2, 1.1-4.2 for highest versus lowest quartile, P trend= 0.02) but block hours (taxi plus flight time) per year was not (OR adj1.2, 95% CI 0.6-2.2 for highest versus lowest quartile, P trend=0.38).

CONCLUSION

Flight attendants were no more likely than teachers to report endometriosis. Odds of endometriosis increased with number of flight segments flown per year. This suggests that some aspect of work scheduling is associated with increased risk of endometriosis, or endometriosis symptoms might affect how flight attendants schedule their flights.

Risk profiles for endometriosis in Japanese women: results from a repeated survey of self-reports

Background

The prevalence and risk factors for endometriosis may differ according to diagnosis methodologies, such as study populations and diagnostic accuracy. We examined risk profiles in imaging-diagnosed endometriosis with and without surgical confirmation in a large population of Japanese women, as well as the differences in risk profiles of endometriosis based on history of infertility.

Methods

Questionnaires that included items on sites of endometriosis determined by imaging techniques and surgical procedure were mailed to 1025 women who self-reported endometriosis in a baseline survey of the Japan Nurses’ Health Study (n = 15 019).

Results

Two hundred and ten women had surgically confirmed endometriosis (Group A), 120 had imaging-diagnosed endometriosis without a surgical procedure (Group B), and 264 had adenomyosis (Group C). A short menstrual cycle at 18–22 years of age and cigarette smoking at 30 years of age were associated with significantly increased risk of endometriosis (Group A plus Group B), while older age was associated with risk of adenomyosis (Group C). In women with a history of infertility, a short menstrual cycle was associated with a significantly increased risk of endometriosis in both Group A and Group B, but risk profiles of endometriosis were different between Group A and Group B in women without a history of infertility.

Conclusions

Women with surgically confirmed endometriosis and those with imaging-diagnosed endometriosis without surgery have basically common risk profiles, but these risk profiles are different from those with adenomyosis. The presence of a history of infertility should be taken into consideration for evaluation of risk profiles.

World Endometriosis Research Foundation Endometriosis Phenome and Biobanking Harmonization Project: II. Clinical and covariate phenotype data collection in endometriosis research

OBJECTIVE

To harmonize the collection of nonsurgical clinical and epidemiologic data relevant to endometriosis research, allowing large-scale collaboration.

DESIGN

An international collaboration involving 34 clinical/academic centers and three industry collaborators from 16 countries on five continents.

SETTING

In 2013, two workshops followed by global consultation, bringing together 54 leaders in endometriosis research.

PATIENTS

None.

INTERVENTION(S)

Development of a self-administered endometriosis patient questionnaire (EPQ), based on [1] systematic comparison of questionnaires from eight centers that collect data from endometriosis cases (and controls/comparison women) on a medium to large scale (publication on >100 cases); [2] literature evidence; and [3] several global consultation rounds.

MAIN OUTCOME MEASURE(S)

Standard recommended and minimum required questionnaires to capture detailed clinical and covariate data.

RESULT(S)

The standard recommended (EPHect EPQ-S) and minimum required (EPHect EPQ-M) questionnaires contain questions on pelvic pain, subfertility and menstrual/reproductive history, hormone/medication use, medical history, and personal information.

CONCLUSION(S)

The EPQ captures the basic set of patient characteristics and exposures considered by the WERF EPHect Working Group to be most critical for the advancement of endometriosis research, but is also relevant to other female conditions with similar risk factors and/or symptomatology. The instruments will be reviewed based on feedback from investigators, and-after a first review after 1 year-triannually through systematic follow-up surveys. Updated versions will be made available through http://endometriosisfoundation.org/ephect.

Endometriosis and the Enigmatic Question of Progression

Aims

The aim of this study was to identify whether endometriosis is a progressive disease with age, and to review the literature on this topic.

Material and methods

The incidence of endometriosis in a cohort of 500 women who underwent laparoscopy between 2003 and 2013 in the Greenville Health System, in South Carolina, United States, was reviewed. The search of the world literature on progression of endometriosis was limited to 1980 and beyond.

Results

The correlation between stage of endometriosis and age was found to be small (r = −0.04; 95% CI, −0.13 to 0.04; p = 0.3; n = 471). The literature search identified 16 studies on adults. Progression of endometriosis findings at laparoscopy occurred in 31% of the cases with follow-up (n = 162).

Conclusions

Endometriosis of minimal or mild American Society for Reproductive Medicine (rASRM) classification stage is equally likely to be present in women of all ages; similarly, endometriosis in its severe form is not age-dependent.

Severe teenage acne and risk of endometriosis

STUDY QUESTION

Is there a relationship between severe teenage acne and endometriosis?

SUMMARY ANSWER

Endometriosis is positively associated with severe teenage acne.

WHAT IS KNOWN ALREADY

No studies have specifically explored a possible association between severe acne in adolescence and risk of endometriosis.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study used data collected from 88 623 female nurses from September 1989 to June 2009 as part of the Nurses' Health Study II (NHS II) cohort.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Regression models were used to calculate hazard ratios (HRs) and confidence intervals (CIs) for endometriosis among women with and without severe teenage acne. Multivariate models were adjusted for established risk factors of endometriosis.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 4 382 laparoscopically confirmed endometriosis cases were documented during 1 132 272 woman-years of follow-up. Compared with women without a history of severe teenage acne, women who had severe teenage acne had a 20% increased risk of endometriosis (HR = 1.20, 95% CI: 1.08-1.32). The association was not affected by adjusting for use of tetracycline or isotretinoin.

LIMITATIONS AND REASONS FOR CAUTION

The HR is likely to be underestimated since we only included endometriosis cases confirmed by laparoscopy. Although geographically diverse, the NHS II cohort is primarily Caucasian, which may limit generalization to more ethnically diverse populations.

WIDER IMPLICATIONS OF THE STUDY

The results of this study suggest that severe teenage acne is associated with an increased risk of endometriosis. As a visible and non-invasive clinical indicator, severe teenage acne may be useful for early detection of endometriosis. We bring this counter-intuitive association to the attention of clinicians for the benefit of the patient and an early diagnosis of endometriosis.

STUDY FUNDING/COMPETING INTEREST

This study was funded by research grant CA176726 from the National Institute of Health. M.K. is supported by a Marie Curie International Outgoing Fellowship within the 7th European Community Framework Programme (#PIOF-GA-2011-302078). The funding agencies had no role in the design of the study, in the analysis and interpretation of the data, in the writing of the report or in the decision to submit the paper for publication.

Air pollution exposures during adulthood and risk of endometriosis in the Nurses' Health Study II

BACKGROUND

Particulate matter and proximity to large roadways may promote disease mechanisms, including systemic inflammation, hormonal alteration, and vascular proliferation, that may contribute to the development and severity of endometriosis.

OBJECTIVE

Our goal was to determine the association of air pollution exposures during adulthood, including distance to road, particulate matter<2.5 μm, between 2.5 and 10 μm, and <10 μm, (PM2.5, PM10-2.5, PM10), and timing of exposure with risk of endometriosis in the Nurses' Health Study II.

METHODS

Proximity to major roadways and outdoor levels of PM2.5, PM10-2.5, and PM10 were determined for all residential addresses from 1993 to 2007. Multivariable-adjusted time-varying Cox proportional hazard models were used to estimate the relation between these air pollution exposures and endometriosis risk.

RESULTS

Among 84,060 women, 2,486 incident cases of surgically confirmed endometriosis were identified over 710,230 person-years of follow-up. There was no evidence of an association between endometriosis risk and distance to road or exposure to PM2.5, PM10-2.5, or PM10 averaged over follow-up or during the previous 2- or 4-year period.

CONCLUSIONS

Traffic and air pollution exposures during adulthood were not associated with incident endometriosis in this cohort of women.