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

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 Causal Evidence of Birth Weight and Female-Related Traits and Diseases: A Two-Sample Mendelian Randomization Analysis

Objectives: A large meta-analysis indicated a more pronounced association between lower birth weight (BW) and diseases in women but less concern about the causality between BW and female-related phenotypes and diseases.

Methods: Mendelian randomization (MR) analysis was used to estimate the causal relationship between two traits or diseases using summary datasets from genome-wide association studies. Exposure instrumental variables are variants that are strongly associated with traits and are tested using four different statistical methods, including the inverse variance weighting, MR-Egger, weighted median, and weighted mode in MR analysis. Next, sensitivity analysis and horizontal pleiotropy were assessed using leave-one-out and MR-PRESSO packages.

Results: The body mass index (BMI) in adulthood was determined by BW (corrected β = 0.071, p = 3.19E-03). Lower BW could decrease the adult sex hormone-binding globulin (SHBG) level (β = −0.081, p = 2.08E-06), but it resulted in increased levels of bioavailable testosterone (bio-T) (β = 0.105, p = 1.25E-05). A potential inverse effect was observed between BW and menarche (corrected β = −0.048, p = 4.75E-03), and no causal association was confirmed between BW and the risk of endometriosis, leiomyoma, and polycystic ovary syndrome.

Conclusion: Our results suggest that BW may play an important role and demonstrates a significant direct influence on female BMI, SHBG and bio-T levels, and menarche.

Height and pelvic lesion number: Do they have a positive relationship with postoperative recurrence in adolescent endometriosis?-A retrospective clinical analysis of 89 adolescent endometriosis in China

BACKGROUND

Adolescent endometriosis is a special type of endometriosis. Its diagnosis is often delayed. This study aimed to share the treatment experience of adolescent endometriosis and analyze the clinical manifestation, clinical stage, and risk factors of postoperative recurrence in China.

METHODS

Eighty-nine cases of adolescent endometriosis over 7 years in a single institution were reviewed. Demographic, clinical outcome measures were collected.

RESULT

The cumulative incidence rates of postoperative recurrence at years 1, 2, 3, 4, and 5 were 13.2%, 15.09%, 16.98%, 20.75%, and 20.75%, respectively. The risk factors associated with postoperative recurrence were disease stage, number of lesions, and height. In multivariate analysis, the independent risk factors of postoperative recurrence were height (RR: 1.132, 95% CI: 1.018-1.260) and the number of pelvic lesions (three or more, RR: 4.202, 95% CI: 1.013-17.433).

CONCLUSION

Taller patients and those who had multiple lesion sites (≥3) should receive more attention, because they have a higher possibility of relapse after surgery than their counterparts. This finding can guide the postoperative treatment of adolescent patients with endometrioma.

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.

Incidence, prevalence, and trends in endometriosis diagnosis: a United States population-based study from 2006 to 2015

BACKGROUND

Accurate estimates of incidence and prevalence of endometriosis among nonselected cohorts are lacking in the United States, and earlier reports have produced varying results.

OBJECTIVE

This study aimed to define endometriosis incidence and prevalence in a US population and evaluate factors influencing these estimates over time.

STUDY DESIGN

A 10-year retrospective cohort study using Kaiser Permanente Washington electronic health records database was completed. The primary analysis included women enrollees aged 16 to 60 years, from January 2006 to December 2015, who had a uterus, were continuously enrolled for at least 2 years before cohort entry and had at least 1 healthcare utilization. Secondary analysis included all women enrollees aged 16 to 60 years during this time. Incident endometriosis was identified using the International Classification of Diseases, Ninth Revision and Tenth Revision, diagnosis codes. Annual incidence rates were age-adjusted by direct standardization to the 2015 study population. Secular trends in incidence overall and by 5-year age group, race and ethnicity, diagnosis modality, and practitioner type were assessed using Poisson regression analyses. Prevalent cases were defined as women enrolled in 2015 and had an endometriosis diagnosis before the end of 2015. The prevalence rates of chronic pelvic pain and dysmenorrhea defined by the International Classification of Diseases, Ninth Revision and Tenth Revision, diagnosis codes in 2006-2015 were estimated.

RESULTS

Among 332,056 eligible women who contributed 1,176,329 person-years during the 10-year study period, 2863 incident endometriosis cases were identified for an average incidence of 24.3 cases per 10,000 person-years. In our primary analysis, incidence rates declined over the study interval from a high of 30.2 per 10,000 person-years in 2006 to 17.4 per 10,000 person-years in 2015 and were highest among women aged 36 to 45 years in most years. Incidence rates were similar across race and ethnicity groups. The distribution of the 2863 incident cases by the diagnosis modality was as follows: 45.5% surgical, 5.7% imaging, and 48.8% clinical. Endometriosis incidence rates per 10,000 person-years were similar in women who were surgically and clinically diagnosed and decreased significantly from 2006 to 2015 (surgically diagnosed endometriosis dropped from 13.4 to 7.4 and clinically diagnosed endometriosis dropped from 16.1 to 8.9; P value of <.001 for linear trend over time for each). Incident case distribution by diagnosing provider was as follows: 73.6% obstetrician and gynecologist, 15.7% primary care provider, and 10.7% "other." Incidence of endometriosis diagnosed by an obstetrician and gynecologist and primary care provider decreased over the study interval (P<.001 for linear trend over time for each). Method of diagnosis and provider type did not differ by race and ethnicity. Among 135,162 women who contributed person-time in 2015, 2521 women were diagnosed with endometriosis, a prevalence rate of 1.9%. In our secondary analysis, the frequency of chronic pelvic pain diagnosis increased over the study interval from 3.0% in 2006 to 5.6% in 2015.

CONCLUSION

The incidence rates of endometriosis declined over the 10-year study interval and did so uniformly across age groups, races and ethnicities, and the main diagnosing modalities and providers. Declining rates may reflect a shift in practice patterns in the United States away from the diagnosis of endometriosis both clinically and surgically, rather than favoring more general diagnoses of chronic pelvic pain. The prevalence of endometriosis in 2015 in the United States is in keeping with data from recent studies outside the United States using health record data.

The Formidable yet Unresolved Interplay between Endometriosis and Obesity

Obesity and endometriosis are two very common entities, yet there is uncertainty on their exact relationship. Observational studies have repeatedly shown an inverse correlation between endometriosis and a low body mass index (BMI). However, obesity does not protect against endometriosis and on the contrary an increased BMI may lead to more severe forms of the disease. Besides, BMI is not accurate in all cases of obesity. Consequently, other anthropometric and phenomic traits have been studied, including body adiposity content, as well as the effect of BMI early in life on the manifestation of endometriosis in adulthood. Some studies have shown that the phenotypic inverse correlation between the two entities has a genetic background; however, others have indicated that certain polymorphisms are linked with endometriosis in females with increased BMI. The advent of metabolic bariatric surgery and pertinent research have led to the emergence of biomolecules that may be pivotal in understanding the pathophysiological interaction of the two entities, especially in the context of angiogenesis and inflammation. Future research should focus on three objectives: detection and interpretation of obesity-related biomarkers in experimental models with endometriosis; integration of endometriosis-related queries into bariatric registries; and multidisciplinary approach and collaboration among specialists.

Epidemiology of Adenomyosis

Adenomyosis, characterized by the presence of endometrial glands and stroma within the myometrium, can have a substantial impact on the quality of women's lives. Despite this, the epidemiologic research on this condition lags considerably behind that of other noncancerous reproductive health conditions. The lack of progress and knowledge is due in part to the challenges in designing valid epidemiologic studies, since the diagnosis of adenomyosis historically has been limited to the examination of uterine specimens from hysterectomy. This review describes the available data on the frequency of this condition and the epidemiologic investigation thus far into the risk factors for disease-highlighting the methodologic and inference challenges primarily around study sample selection. We conclude with providing recommendations for approaches to future epidemiologic study that capitalize on the advancements in imaging technology to detect adenomyosis and provide a fuller picture of the occurrence and risk factors for disease.