Early life factors for endometriosis: a systematic review

Childhood adversity and risk of endometriosis, fibroids, and polycystic ovary syndrome: a systematic review

IMPORTANCE

Although childhood adversity has been extensively studied in relation to various health outcomes, investigation of its association with gynecological conditions remains limited.

OBJECTIVE

To systematically review studies examining the effect of childhood adversity on the prevalence of three gynecological conditions: endometriosis; fibroids; and polycystic ovary syndrome (PCOS) in the population.

EVIDENCE REVIEW

Six databases were searched from inception to March 12, 2024. Observational studies of women with exposure to adversity before the age of 18 and an outcome of endometriosis, fibroids, and/or PCOS were eligible for inclusion. Studies were summarized through a qualitative synthesis. We evaluated the risk of bias using the Newcastle-Ottawa Scale.

FINDINGS

Seven studies that reported on the association between a form of childhood adversity and endometriosis, fibroids, and or PCOS were selected for review. All seven studies received a moderate risk of bias score. Cumulative exposure to childhood adversity was associated with an increased risk of endometriosis and fibroids. Childhood exposure to sexual abuse was associated with an increased risk of endometriosis and fibroids. Exposure to physical abuse in childhood was associated with a greater risk of fibroids.

CONCLUSION AND RELEVANCE

A small number of studies have shown an association between childhood adversity and the development of endometriosis and fibroids in later life. These initial findings warrant further investigation in larger studies using standardized measures.

Understanding diagnostic delay for endometriosis: A scoping review using the social-ecological framework

Diagnostic delay for endometriosis is a well-established phenomenon. Despite this, little is known about where in the health care system these delays occur or why they occur. Our review is the first attempt to synthesize and analyze this international evidence. A systematic scoping review with a pre-specified protocol incorporated the literature on diagnostic delay for endometriosis using the social-ecological theoretical framework. Four databases (PubMed, MEDLINE, EMBASE, PsychINFO) were searched from inception to September 2023. The search yielded 403 studies, 23 of which met the inclusion criteria. Most were from high-income country researchers. The average diagnostic delay reported across studies was 6.8 years (range 1.5-11.4 years) but this masked the very wide differences reported between countries. Considering the impact on individuals and the health system, addressing diagnostic delay for endometriosis must remain a priority for researchers, health care providers and policy makers.

Proposal for targeted, neo-evolutionary-oriented, secondary prevention of early-onset endometriosis and adenomyosis. Part I: pathogenic aspects

The potential for repeated ovulation and menstruation is thought to have provided a Darwinian advantage during the Palaeolithic. Reproductive conditions remained relatively stable until the pre-industrial era, characterized by late menarche, very young age at first birth, multiple pregnancies, and prolonged periods of lactational amenorrhoea. For hundreds of thousands of years, menstruators experienced few ovulatory cycles, even though they were genetically adapted to ovulate and menstruate every month. In the post-industrial era, the age at menarche gradually declined, the age at first birth progressively increased, and breastfeeding became optional and often of short duration. This created a mismatch between genetic adaptation and socio-environmental evolution, so that what was initially a probable reproductive advantage subsequently contributed to increased susceptibility to diseases associated with lifetime oestrogen exposure, such as ovarian, endometrial and breast cancer and, hypothetically, also those associated with the number of ovulatory menstruations, such as endometriosis and adenomyosis. The incidence of endometriosis shows a steep and progressive increase around the age of 25 years, but given the consistently reported delay in diagnosis, the actual incidence curve should be shifted to the left, supporting the possibility that the disease has its roots in adolescence. This raises the question of whether, from an evolutionary point of view, anovulation and amenorrhoea should not still be considered the physiological state, especially in the postmenarchal period. However, an increase in the frequency of endometriosis in recent decades has not been demonstrated, although this deserves further epidemiological investigation. In addition, as endometriosis occurs in a minority of individuals exposed to retrograde menstruation, other important pathogenic factors should be scrutinised. Research should be resumed to explore in more detail the transtubal reflux of not only blood, but also endometrial cells, and whether they are systematically present in the peritoneal fluid after menstruation. If repetitive ovulatory menstruation during the early reproductive years is shown to increase the risk of endometriosis and adenomyosis development and progression in susceptible individuals, hormonal interventions could be used as secondary prevention in symptomatic adolescents.

Insights from Mendelian randomization and genetic correlation analyses into the relationship between endometriosis and its comorbidities

BACKGROUND

Endometriosis remains a poorly understood disease, despite its high prevalence and debilitating symptoms. The overlap in symptoms and the increased risk of multiple other traits in women with endometriosis is becoming increasingly apparent through epidemiological data. Genetic studies offer a method of investigating these comorbid relationships through the assessment of causal relationships with Mendelian randomization (MR), as well as identification of shared genetic variants and genes involved across traits. This has the capacity to identify risk factors for endometriosis as well as provide insight into the aetiology of disease.

OBJECTIVE AND RATIONALE

We aim to review the current literature assessing the relationship between endometriosis and other traits using genomic data, primarily through the methods of MR and genetic correlation. We critically examine the limitations of these studies in accordance with the assumptions of the utilized methods.

SEARCH METHODS

The PubMed database was used to search for peer-reviewed original research articles using the terms 'Mendelian randomization endometriosis' and '"genetic correlation" endometriosis'. Additionally, a Google Scholar search using the terms '"endometriosis" "mendelian randomization" "genetic correlation"' was performed. All relevant publications (n = 21) published up until 7 October 2022 were included in this review. Upon compilation of all traits with published MR and/or genetic correlation with endometriosis, additional epidemiological and genetic information on their comorbidity with endometriosis was sourced by searching for the trait in conjunction with 'endometriosis' on Google Scholar.

OUTCOMES

The association between endometriosis and multiple pain, gynaecological, cancer, inflammatory, gastrointestinal, psychological, and anthropometric traits has been assessed using MR analysis and genetic correlation analysis. Genetic correlation analyses provide evidence that genetic factors contributing to endometriosis are shared with multiple traits: migraine, uterine fibroids, subtypes of ovarian cancer, melanoma, asthma, gastro-oesophageal reflux disease, gastritis/duodenitis, and depression, suggesting the involvement of multiple biological mechanisms in endometriosis. The assessment of causality with MR has revealed several potential causes (e.g. depression) and outcomes (e.g. ovarian cancer and uterine fibroids) of a genetic predisposition to endometriosis; however, interpretation of these results requires consideration of potential violations of the MR assumptions.

WIDER IMPLICATIONS

Genomic studies have demonstrated that there is a molecular basis for the co-occurrence of endometriosis with other traits. Dissection of this overlap has identified shared genes and pathways, which provide insight into the biology of endometriosis. Thoughtful MR studies are necessary to ascertain causality of the comorbidities of endometriosis. Given the significant diagnostic delay of endometriosis of 7-11 years, determining risk factors is necessary to aid diagnosis and reduce the disease burden. Identification of traits for which endometriosis is a risk factor is important for holistic treatment and counselling of the patient. The use of genomic data to disentangle the overlap of endometriosis with other traits has provided insights into the aetiology of endometriosis.

Epigenetics, endometriosis and sex steroid receptors: An update on the epigenetic regulatory mechanisms of estrogen and progesterone receptors in patients with endometriosis

Endometriosis is a benign gynecological disease affecting ∼10% of reproductive-aged women and is defined as the presence of endometrial glands and stroma outside the uterine cavity. Endometriosis can cause a variety of health problems, from pelvic discomfort to catamenial pneumothorax, but it's mainly linked with severe and chronic pelvic pain, dysmenorrhea, and deep dyspareunia, as well as reproductive issues. The pathogenesis of endometriosis involves an endocrine dysfunction, with estrogen dependency and progesterone resistance, and inflammatory mechanism activation, together with impaired cell proliferation and neuroangiogenesis. The present chapter aims to discuss the main epigenetic mechanisms related to estrogen receptors (ERs) and progesterone receptors (PRs) in patients with endometriosis. There are numerous epigenetic mechanisms participating in endometriosis, regulating the expression of the genes encoding these receptors both indirectly, through the regulation of transcription factors, and directly, through DNA methylation, histone modifications, micro RNAs and long noncoding RNAs. This represents an open field of investigation, which may lead to important clinical implications such as the development of epigenetic drugs for the treatment of endometriosis and the identification of specific and early biomarkers for the disease.

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.

A Preliminary Study on the Effects of Black Cohosh Preparations on Bone Metabolism of Rat Models With GnRH-a-Induced Peri-Menopausal Symptoms

BACKGROUND

Endometriosis (EMS) is a relapsing and estrogen-dependent disease. For endometriosis such as deep endometriosis and ovarian endometrioid cysts, surgery is the most effective treatment. Long-term follow-up showed that the recurrence rate of endometriosis after surgical treatment was high, so postoperative drugs were needed to reduce recurrence, and Gonadotropin-releasing hormone agonists (GnRH-a) were the most commonly used drug for postoperative management.GnRH-a may reduce the post-treatment endometriosis relapses by lowering the hormone levels in the body. However, the use of GnRH-a can give rise to perimenopausal symptoms, especially osteoporosis, bone loss, and bone pain, for which reason GnRH-a use is often limited. The add-back therapy is often used to alleviate the untoward effects caused by GnRH-a. However, long-term use of hormone drugs may lead to EMS recurrence, thrombosis, and breast cancer. Therefore, a safer and more effective drug is urgently needed to alleviate the untoward effects caused by GnRH-a. In recent years, scholars at home and abroad have found that isopropanolic Cimicifuga racemosa extract (ICR), as a plant extract, can better relieve the symptoms of perimenopausal women. At the same time, some studies have initially confirmed that black cohosh preparations can relieve the perimenopausal symptoms caused by GnRH-a treatment in EMS patients.

OBJECTIVE

To investigate the effect of black cohosh preparations on the bone metabolism of rat models with GnRH-a-induced perimenopausal symptoms.

METHODS

The rat models of perimenopausal symptoms were established by GnRH-a injection. and normal saline (NS injection) was used as the control. According to the modeling method and drug intervention, the rats were randomly divided into four groups: GnRH-a injection + saline intervention group (GnRH-a + NS), saline injection control + saline intervention group (NS + NS), GnRH-a injection + estradiol intervention group (GnRH-a + E2), and GnRH-a injection + black cohosh preparation intervention group (GnRH-a + ICR). The rat models were identified with the vaginal smear method, and then the corresponding drug intervention was administrated for 28 days. After the intervention, the rats were sacrificed. The rats' bone mineral density (BMD) of the distal femur was detected by a dual-energy X-ray bone density scanner. Rat tibia bone tissues were decalcified and made into slices. The pathological and morphological changes of rat tibial bones in each group were observed through HE staining. Histomorphometry parameters of rat tibial bones in each group, such as trabecular bone volume (TBV), trabecular thickness (TbTh), trabecular number (TbN), and trabecular spacing (TbSp), were detected and analyzed by using an automatic image analysis system.

RESULTS

(1) The BMD level of the distal femur in the GnRH-a + NS group was significantly lower than the NS + NS, GnRH-a + E2, and GnRH-a + ICR groups (P<0.01), the BMD levels in GnRH-a + E2 and GnRH-a + ICR groups were slightly lower than the NS + NS group, but there was no significant difference among the three groups (P>0.05). (2) The pathological changes of the tibia bones under the microscope in different groups were as follows: The tibia bone trabecular structure was normal in the NS + NS group, without trabecular thinning or fracture, and the arch structure was normal. In the GnRH-a + NS group, some trabecular structures tapered, the arch structure disappeared, but no obvious bone fracture was observed in the trabecula. In the GnRH-a + E2 and GnRH-a + ICR groups, the trabecular structures were normal, without trabecular bone thinning or fracture, and the arch structures were normal. (3) The TBV level of the GnRH-a + INS group was significantly lower than that of the NS + NS, GnRH-a + E2 and GnRH-a + ICR groups (P<0.01, P<0.05, P<0.01), while there was no significant difference among NS + NS, GnRH-a + E2 and GnRH-a + ICR groups (P>0.05). (4) The TbTh levels in the four groups had no significant difference (P>0.05). Compared with the NS + NS group, the TbTh levels in the GnRH-a + NS, GnRH-a + E2, and GnRH-a + ICR groups showed a descending tendency, while the TbTh levels in the GnRH-a + E2 and GnRH-a + ICR groups were slightly higher than that of the GnRH-a + NS group. However, such differences were not significant statistically (P>0.05). (5) Compared with the NS + NS group, the TbN levels in the GnRH-a + NS, GnRH-a + E2, and GnRH-a + ICR groups decreased remarkably (P<0.05). Compared with the GnRH-a + NS group, the TbN levels in the GnRH-a + E2 and GnRH-a + ICR groups showed a mild descending tendency, but such differences were not significant statistically (P>0.05). (6) The TbSp level of the GnRH-a + NS group was significantly higher than that of the NS + NS, GnRH-a + E2, and GnRH-a + ICR groups (P<0.01), while there was no significant difference among NS + NS, GnRH-a + E2 and GnRH-a + ICR groups (P>0.05).

CONCLUSION

The GnRH-a injection could achieve the desired effect. GnRH-a injection may lead to the loss of bone mass in rats. Black cohosh preparations, like estrogen, may have a protective effect on bone mass loss caused by GnRH-a injection.

Multigenerational endometriosis : consequence of fetal exposure to diethylstilbestrol ?

BACKGROUND

Endometriosis, which affects 10-15 % of women of reproductive age, is an estrogen-driven condition influenced by environmental and genetic factors. Exposition to estrogen-like endocrine-disrupting chemicals (EDCs) has been reported to contribute to the fetal origin of this disease.

CASE PRESENTATION

We report here an informative family in which all prenatally DES-exposed daughters and subsequent granddaughters presented endometriosis, whereas the unexposed first daughter and her progeny presented no gynecological disorders. Moreover, the only post-pubertal great-granddaughter, who presents chronic dysmenorrhea that remains resistant to conventional therapy, is at risk of developing endometriosis. The mother (I-2) was prescribed DES (30 mg/day for 3 months) to inhibit lactation after each delivery.

CONCLUSIONS

Although a direct causal link between the grandmother's treatment with DES and the development of endometriosis in possibly three exposed generations remains speculative, this report strengthens the suspicion that fetal exposition to DES contributes to the pathogenesis of adult diseases, such as endometriosis. It also highlights a multigenerational and likely transgenerational effect of EDCs.

HSF1 promotes endometriosis development and glycolysis by up-regulating PFKFB3 expression

BACKGROUND

Endometriosis is a chronic hormonal inflammatory disease characterized by the presence of endometrial tissue outside the uterus. Endometriosis often causes infertility, which brings physical and mental pain to patients and their families.

METHODS

We examined the functions of heat shock factor 1 (HSF1) in endometriosis development through cell count assay, cell-scratch assay and clone formation experiments. We used quantitative real-time PCR (qRT-PCR) and Western blot (WB) to detect HSF1 expression. Glucose and lactate levels were determined using a glucose (GO) assay kit and a lactate assay kit. Furthermore, we used a HSF1 inhibitor-KRIBB11 to establish a mouse model of endometriosis.

RESULTS

Our data demonstrated that HSF1 promoted endometriosis development. Interestingly, HSF1 enhanced glycolysis via up-regulating PFKFB3 expression in endometriosis cells, which was a key glycolysis enzyme. Consistently, the HSF1 inhibitor KRIBB11 could abrogate endometriosis progression in vivo and in vitro.

CONCLUSIONS

Findings indicate that HSF1 plays an important role in endometriosis development, which might become a new target for the treatment of endometriosis.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary data are available.

Quality of life among infertile women with endometriosis undergoing IVF treatment and their pregnancy outcomes

OBJECTIVE

We assessed the quality of life (QoL) and pregnancy outcomes of in vitro fertilization (IVF) treatment among infertile women with endometriosis, as compared to infertile women without endometriosis.

STUDY DESIGN

Eighty-one (81) endometriosis women (with 142 embryo transfer [ET] cycles) and 605 non-endometriosis women (with 1063 ET cycles) were included. QoL was measured by FertiQoL at the date before ET. Pregnancy outcomes included biochemical pregnancy, ongoing pregnancy and live birth. Generalized estimating equation analyses were performed to assess the association between QoL and IVF pregnancy.

RESULTS

Endometriosis-affected women had significantly lower QoL, as indicated by mind/body, treatment environment and total treatment scores, and total scores of FertiQoL (p < .05), compared to those without endometriosis. Among non-endometriosis women, QoL scores were significantly associated with successful IVF pregnancy; with one unit increase in QoL scores as measured by emotional domain of FertiQoL, the probabilities of ongoing pregnancy and live birth significantly increased by 2.5% and 2.8%, respectively (p < .05). This association was also observed among endometriosis women but it did not reach statistical significance.

CONCLUSIONS

Lower QoL among women with endometriosis versus non-endometriosis during IVF treatment highlights the importance of developing strategies to improve their QoL, which may enhance following pregnancy rates in this population.

Systematic Review and Meta-Analysis of Incidence and Prevalence of Endometriosis

There is still much controversy regarding the epidemiology of endometriosis. The objective of this work is to conduct a systematic review, and if possible, proceed with a meta-analysis of studies that have analyzed the incidence and prevalence of this condition among women in the general population. The inclusion criteria were papers published after 1997 that had reported data of the incidence or prevalence of endometriosis. The PubMed search engine was used to identify papers meeting the inclusion criteria from 1997 to 2019, with an additional manual search for the identification of potentially eligible studies. The search was limited to papers published in English. The risk of bias was assessed according to the Joanna Briggs Institute Critical Appraisal Checklist. As a result, 27 papers, which included a total of 28,660,652 women, were classified according to the type of design and sources of information in five subgroups. Pooled estimates of prevalence for studies with self-reported data were 0.05 (95% CI: 0.03; 0.06), 0.01 for population-based integrated information systems (95% CI: 0.01; 0.02), and 0.04 (95% CI 0.04; 0.05) in studies using other designs. The pooled incidence rate of endometriosis was: 1.36 per 1000 person-years (PY) (95% CI: 1.09; 1.63) for studies based on hospital discharges, 3.53 per 1000 PY (95% CI: 2.06; 4.99) for cohort studies, and 1.89 per 1000 PY (95% CI: 1.42; 2.37) for population-based integrated information systems. Meta-analysis indicated high heterogeneity based on I-squared statistics. This significant variability may not only be due to methodological issues and the specific limitations of the different designs and data analyzed, including case definitions and subject selection strategies, but also to the inherent heterogeneity of endometriosis. Epidemiological studies with appropriate study designs remain necessary to provide a valid estimation of the population burden of endometriosis.