Common genetic influences underlie comorbidity of migraine and endometriosis

Investigating migraine phenotype and dynamics in women with endometriosis: an observational pilot study

INTRODUCTION

Migraine and endometriosis are chronic disabling pain conditions. There is evidence for a shared genetic background. Migraine phenotype and course in patients with the comorbidity are insufficient investigated. Both conditions can be treated with progestins.

METHODS

For this observational study we included women with migraine and endometriosis, visiting our clinic from 2015 to 2021. We collected available information from charts and complemented these data by a structured phone interview to collect more specific information on migraine and the course of both diseases.

RESULTS

From 344 patients fulfilling the inclusion criteria, 94 suffered from both, endometriosis and migraine. Migraine with aura was reported by 41% of the patients and was associated with earlier onset of migraine (age < 17 years (OR 6.54) and with a history of medication overuse headache (OR 9.9, CI 1.6-59.4). Present monthly migraine frequency (1.5 ± 2.6) was significantly lower than five years before the interview (2.9 ± 4.64). There was a correlation between medication overuse headache and use of analgesics more than 3 days/months for dysmenorrhoea (p < 0.03). ASRM endometriosis score was not associated with migraine characteristics.

CONCLUSIONS

We conclude that the comorbidity of endometriosis is highly linked to migraine with aura. Migraine onset in these patients was earlier. Further studies are needed to explore, if the observed decrease in migraine frequency can be attributed to recent endometriosis surgery and to understand if early diagnosis and treatment of both conditions may contribute to improve the course of both conditions. Trial registration BASEC Nr. 2021-00285.

Migraine heritability and beyond: A scoping review of twin studies

OBJECTIVE

This scoping review aimed to summarize current knowledge from twin studies on migraine. Migraine heritability, genetic correlations with migraine comorbid disorders, and the use of discordant twin pairs in migraine research are described. Further, the review considers the unused potential of twin studies in migraine research and reflects on future directions.

BACKGROUND

Twin studies can be used to understand how heritable and environmental factors influence human traits and disorders. The classical twin design compares the resemblance of a trait in monozygotic twins to that in dizygotic twins. The classical twin design can be extended to estimate the genetic correlation between disorders, model causality, and describe differences within discordant twin pairs.

METHODS

Studies focusing on migraine and using a twin study design were included. The search was performed on the PubMed-MEDLINE database using the search terms "migraine" AND "twin" OR "twins." It was done in May 2023, rerun in November 2023, and managed with the Covidence software.

RESULTS

The search identified 52 twin studies on migraine. In 24 papers, the heritability of migraine was estimated with a classical twin design. Heritability estimates ranged from 0.36 to 0.48 for studies with adults, both men and women, and unspecified migraine. Migraine heritability was predominantly estimated with twin cohorts of North European ancestry, and only two studies examined migraine subtypes. A multilevel classical twin design was used in 11 studies to examine the co-occurrence between migraine and comorbid disorders. The differences within migraine discordant twin pairs were examined in nine studies.

CONCLUSION

The heritability of migraine was estimated with a classical twin design in twin cohorts from seven different countries, with remarkably similar results across studies. Future studies should include migraine subtypes and twin cohorts of non-North European ancestry to better reflect the global population. Beyond heritability estimations, the twin method is a valuable tool for understanding causality and describing differences within discordant twin pairs. Despite more than 80 years of twin studies in migraine research, the twin design has a large unused potential to advance our understanding of migraine.

Migraine among women with endometriosis: a hospital-based case-control study in Bangladesh

BACKGROUND

Endometriosis is a disease among women of reproductive age, which causes several health problems, such as dysmenorrhea, dyspareunia, and subfertility. In addition, it increases psychological stress and often results in marital disharmony. Similarly, migraine is more frequent among this group of women. Several studies have shown an association between endometriosis and migraine among groups of populations completely different from Bangladesh.

OBJECTIVE

This study aimed to identify the association between endometriosis and migraine among the Bangladeshi population.

STUDY DESIGN

This nonrandomized case-control study was conducted with cases of endometriosis and controls without endometriosis who were confirmed by laparoscopy or laparotomy. Among the study participants, cases of migraine in 1 group of respondents who were already diagnosed as patients of migraine were identified, and the others with complaints of headaches were further confirmed by a medicine specialist. Patients were recruited from the Department of Obstetrics and Gynecology at the Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders General Hospital and Ibrahim Medical College. The study was approved by the ethical review committee of the Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders General Hospital. Multivariate logistic regression was used to identify the association between endometriosis and migraine using odds ratios and 95% confidence intervals.

RESULTS

Of 1496 patients who underwent laparoscopy or laparotomy during the study period, the frequency of endometriosis was found to be 12.7%. A total of 190 patients with confirmed endometriosis cases and an equal number of controls without endometriosis were enrolled, maintaining the age distribution of the controls similar to that of the cases. Compared with controls, the distribution of age, body mass index, education, and marital status of the patients with endometriosis were similar. The average ages of respondents were 30.6 years in both the case and control groups. Regarding occupation, cases included more students than controls (12% vs 0%, respectively). The odds of suffering from dysmenorrhea and dyspareunia among the cases were 3.3 (95% confidence interval, 2.66-4.15; P<.001) and 9.5 (95% confidence interval, 5.3-17.9; P<.001) times higher than that of controls, respectively. In addition, the odds of menstrual irregularity was 60% lower among the cases than among controls (odds ratio, 0.4; 95% confidence interval, 0.24-0.64; P<.001). No significant difference was observed in having primary subfertility and secondary subfertility among the 2 groups of respondents. Univariate regression analysis showed that patients with endometriosis have 6.13 times higher odds (95% confidence interval, 2.50-18.40; P<.001) of having a migraine and 2.00 times higher odds (95% confidence interval, 1.2-3.2; P=.01) of having a headache than controls. Furthermore, the age- and body mass index-adjusted multivariate model showed that patients with endometriosis have 5.4 times higher odds of having migraine than patients without endometriosis (95% confidence interval, 2.11-16.4; P<.001). In addition, the higher the age of reproductive-age women, the higher the odds of having migraine. A 1-year increase in age increases the odds of having migraine by 23% (odds ratio, 1.23; 95% confidence interval, 1.13-1.16; P<.001).

CONCLUSION

Our results support the association between endometriosis and migraine among the Bangladeshi population, which is similar to relevant studies conducted in other geographic locations. The groups of physicians who treat patients suffering from the 2 diseases, endometriosis and migraine, should keep this interrelationship in mind to ensure a better quality of life for the patient.

Prevalence, diagnostic delay and economic burden of endometriosis and its impact on quality of life: results from an Eastern Mediterranean population

BACKGROUND

There are limited data on endometriosis from the Eastern Mediterranean region. This study for the first time estimates the prevalence and impact of endometriosis on women in Northern Cyprus, an under-represented region in Europe.

METHODS

Cyprus Women's Health Research Initiative, a cross-sectional study recruited 7646 women aged 18-55 in Northern Cyprus between January 2018 and February 2020. Cases were identified using self-reported and ultrasound data and two control groups were defined, with (n = 2922) and without (n = 4314) pain. Standardized tools, including the 11-point Numerical Rating Scale and the Short Form 36 Health Survey version 2, were used to assess pain and quality of life, respectively.

RESULTS

Prevalence and median diagnostic delay of endometriosis were 5.4% [95% confidence interval (CI): 4.9-5.9%, n = 410] and 7 (interquartile range 15.5) years. Endometriosis cases experienced a higher prevalence of bladder pain compared with asymptomatic pain controls (6.3% vs. 1.0%, P < 0.001) and irritable bowel syndrome relating to pelvic pain compared with symptomatic (4.6% vs. 2.6%, P = 0.027) and asymptomatic (0.3%, P < 0.001) controls. The odds of endometriosis cases reporting an anxiety diagnosis was 1.56 (95% CI: 1.03-2.38) higher than the symptomatic and 1.95 (95% CI: 1.30-2.92) times higher than the asymptomatic controls. The physical component score of the health-related quality-of-life instrument suggested a significant difference between the endometriosis cases and the symptomatic controls (46.8 vs. 48.5, P = 0.034). Average annual economic cost of endometriosis cases was Int$9864 (95% CI: $8811-$10 917) including healthcare, costs relating to absence and loss of productivity at work.

CONCLUSION

Prevalence was lower than the global 10% estimate, and substantial proportion of women without endometriosis reported moderate/severe pelvic pain hinting at many undiagnosed cases within this population. Coupled with lower quality of life, significant economic burden and underutilized pain management options, the study highlights multiple opportunities to improve care for endometriosis patients and women with pelvic pain.

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.

A Novel Classification of Endometriosis Based on Clusters of Comorbidities

Endometriosis is a heterogeneous, complex, and still challenging disease, due to its epidemiological, etiological and pathogenic, diagnostic, therapeutic, and prognosis characteristics. The classification of endometriosis is contentious, and existing therapies show significant variability in their effectiveness. This study aims to capture and describe clusters of women with endometriosis based on their comorbidity. With data extracted from electronic records of primary care, this study performs a hierarchical clustering with the Ward method of women with endometriosis with a subsequent analysis of the distribution of comorbidities. Data were available for 4055 women with endometriosis, and six clusters of women were identified: cluster 1 (less comorbidity), cluster 2 (anxiety and musculoskeletal disorders), cluster 3 (type 1 allergy or immediate hypersensitivity); cluster 4 (multiple morbidities); cluster 5 (anemia and infertility); and cluster 6 (headache and migraine). Clustering aggregates similar units into similar clusters, partitioning dissimilar objects into other clusters at a progressively finer granularity-in this case, groups of women with similarities in their comorbidities. Clusters may provide a deeper insight into the multidimensionality of endometriosis and may represent diverse "endometriosis trajectories" which may be associated with specific molecular and biochemical mechanisms. Comorbidity-based clusters may be important to the scientific study of endometriosis, contributing to the clarification of its clinical complexity and variability. An awareness of those comorbidities may help elucidate the etiopathogenesis and facilitate the accurate earlier diagnosis and initiation of treatments targeted toward particular subgroups.

Endometriosis and the diagnosis of different forms of migraine: an association with dysmenorrhoea

RESEARCH QUESTION

Women with endometriosis are frequently affected by headache. How many of these have a clear diagnosis of migraine? Are the different forms of migraine related to the phenotypes and/or characteristics of endometriosis?

DESIGN

This was a prospective nested case-control study. A consecutive series of 131 women with endometriosis who attended the endometriosis clinic were enrolled and examined for the presence of headache. A headache questionnaire was used to determine the characteristics of the headaches, and the diagnosis of migraine was confirmed by a specialist. The case group included women with endometriosis and a diagnosis of migraine, while the control group included women with only endometriosis. History, symptoms and other comorbidities were collected. A pelvic pain score and associated symptoms were assessed using a visual analogue scale.

RESULTS

A diagnosis of migraine was made in 53.4% (70/131) of participants. Pure menstrual migraine was reported by 18.6% (13/70), menstrually related migraine by 45.7% (32/70) and non-menstrual migraine by 35.7% (25/70). Dysmenorrhoea and dysuria were significantly more frequent in patients with endometriosis and migraine than in those without migraine (P = 0.03 and P = 0.01). No difference was found for other variables, including age at diagnosis and duration of endometriosis, endometriosis phenotype, the presence of other autoimmune comorbidities or heavy menstrual bleeding. In most patients with migraine (85.7%) the headache symptoms had started years before the diagnosis of endometriosis.

CONCLUSION

The occurrence of headache in many patients with endometriosis is associated with the presence of different forms of migraine, is related to pain symptoms and often precedes the diagnosis 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.

Migraine genetics: Status and road forward

BACKGROUND

Migraine is considered a multifactorial genetic disorder. Different platforms and methods are used to unravel the genetic basis of migraine. Initially, linkage analysis in multigenerational families followed by Sanger sequencing of protein-coding parts (exons) of genes in the genomic region shared by affected family members identified high-effect risk DNA mutations for rare Mendelian forms of migraine, foremost hemiplegic migraine. More recently, genome-wide association studies testing millions of DNA variants in large groups of patients and controls have proven successful in identifying many dozens of low-effect risk DNA variants for the more common forms of migraine with the number of associated DNA variants increasing steadily with larger sample sizes. Currently, next-generation sequencing, utilising whole exome and whole genome sequence data, and other omics data are being used to facilitate their functional interpretation and the discovery of additional risk factors. Various methods and analysis tools, such as genetic correlation and causality analysis, are used to further characterise genetic risk factors.

FINDINGS

We describe recent findings in genome-wide association studies and next-generation sequencing analysis in migraine. We show that the combined results of the two most recent and most powerful migraine genome-wide association studies have identified a total of 178 LD-independent (r² < 0.1) genome-wide significant single nucleotide polymorphisms (SNPs), of which 99 were unique to Hautakangas et al., 11 were unique to Choquet et al., and 68 were identified by both studies. When considering that Choquet et al. also identified three SNPs in a female-specific genome-wide association studies then these two recent studies identified 181 independent SNPs robustly associated with migraine. Cross-trait and causal analyses are beginning to identify and characterise specific biological factors that contribute to migraine risk and its comorbid conditions.

CONCLUSION

This review provides a timely update and overview of recent genetic findings in migraine.

A population-health approach to characterizing migraine by comorbidity: Results from the Mindfulness and Migraine Cohort Study

BACKGROUND

The heterogeneity of migraine has been reported extensively, with identified subgroups usually based on symptoms. Grouping individuals with migraine and similar comorbidity profiles has been suggested, however such segmentation methods have not been tested using real-world clinical data.

OBJECTIVE

To gain insights into natural groupings of patients with migraine using latent class analysis based on electronic health record-determined comorbidities.

METHODS

Retrospective electronic health record data analysis of primary-care patients at Sutter Health, a large open healthcare system in Northern California, USA. We identified migraine patients over a five-year time period (2015-2019) and extracted 29 comorbidities. We then applied latent class analysis to identify comorbidity-based natural subgroups.

RESULTS

We identified 95,563 patients with migraine and found seven latent classes, summarized by their predominant comorbidities and population share: fewest comorbidities (61.8%), psychiatric (18.3%), some comorbidities (10.0%), most comorbidities - no cardiovascular (3.6%), vascular (3.1%), autoimmune/joint/pain (2.2%), and most comorbidities (1.0%). We found minimal demographic differences across classes.

CONCLUSION

Our study found groupings of migraine patients based on comorbidity that have the potential to be used to guide targeted treatment strategies and the development of new therapies.

Medical and Behavioral Aspects of Adolescent Endometriosis: A Review of the Literature

The majority of young women will experience discomfort associated with menstrual cycles and miss out on education and social opportunities. Endometriosis, the presence of endometrial glands and stroma outside of uterus, is the most common cause of secondary dysmenorrhea and characterized by pain despite treatment with nonsteroidal anti-inflammatory drugs and hormonal agents. The true prevalence of adolescent endometriosis is not clear. Delay in diagnosis leads to persistent pain, affects quality of life, and potentially contributes to disease progression and subfertility. A laparoscopic diagnosis is the gold standard, but the surgical appearance may differ from adults, as endometriotic lesions are usually red or clear, making their identification a challenge for gynecologists who are unexperienced with endometriosis in adolescents. A personalized medical–surgical treatment is regarded as the most effective therapeutic strategy to achieve remission of symptoms, suppress disease progression, and protect future fertility. Studies have demonstrated how adolescent endometriosis negatively affects patients’ quality of life and psychosocial functioning. Development of therapeutic interventions targeting psychosocial function and quality of life is imperative for adolescent patients.

Sex hormone-related polymorphisms in endometriosis and migraine: A narrative review

Some evidence indicates endometriosis and migraine have a common genetic predisposition in sex-hormone genes, which could have important implications for the treatment of these two heterogenous conditions. To date, the genes responsibility remains unknown. Based on the biological hypothesis that polymorphisms of genes involved in sex-hormone pathways may influence estrogen levels and phenotypes of both disorders, we did a literature search for candidate sex-hormone genes and genes involved in the metabolism of estradiol. The aim was to review the evidence for shared sex-hormone-related polymorphisms between endometriosis and migraine and provide an exhaustive overview of the current literature. We included case-control studies investigating associations between candidate sex-hormone-related genes and the disorders endometriosis and migraine, respectively. Results showed three overlapping sex-hormone-associated polymorphisms in estrogen receptor genes that are associated with both conditions. To confirm possible associations with other sex-hormone genes, larger studies are needed.

Genetic analysis of endometriosis and depression identifies shared loci and implicates causal links with gastric mucosa abnormality

Evidence from observational studies indicates that endometriosis and depression often co-occur. However, conflicting evidence exists, and the etiology as well as biological mechanisms underlying their comorbidity remain unknown. Utilizing genome-wide association study (GWAS) data, we comprehensively assessed the relationship between endometriosis and depression. Single nucleotide polymorphism effect concordance analysis (SECA) found a significant genetic overlap between endometriosis and depression (P_{Fsig-permuted} = 9.99 × 10^-4). Linkage disequilibrium score regression (LDSC) analysis estimated a positive and highly significant genetic correlation between the two traits (r_G = 0.27, P = 8.85 × 10^-27). A meta-analysis of endometriosis and depression GWAS (sample size = 709,111), identified 20 independent genome-wide significant loci (P < 5 × 10^-8), of which eight are novel. Mendelian randomization analysis (MR) suggests a causal effect of depression on endometriosis. Combining gene-based association results across endometriosis and depression GWAS, we identified 22 genes with a genome-wide significant Fisher's combined P value (FCP_gene < 2.75 × 10^-6). Genes with a nominal gene-based association (P_gene < 0.05) were significantly enriched across endometriosis and depression (P_{binomial-test} = 2.90 × 10^-4). Also, genes overlapping the two traits at P_gene < 0.1 (P_{binomial-test} = 1.31 × 10^-5) were significantly enriched for the biological pathways 'cell-cell adhesion', 'inositol phosphate metabolism', 'Hippo-Merlin signaling dysregulation' and 'gastric mucosa abnormality'. These results reveal a shared genetic etiology for endometriosis and depression. Indeed, additional analyses found evidence of a causal association between each of endometriosis and depression and at least one abnormal condition of gastric mucosa. Our study confirms the comorbidity of endometriosis and depression, implicates links with gastric mucosa abnormalities in their causal pathways and reveals potential therapeutic targets for further investigation.

Migraine, Human Genetics and a Passion for Science

This note reflects on my collaborations with Nick Martin and the GenEpi group over the past 20 years. Over the past two decades, our work together has focused on gene mapping and understanding the genetic architecture of a wide range of traits with particular foci on migraine and common baldness. Our migraine research has included latent class and twin analyses cumulating in genome-wide association analyses which had identified 44 (34 new) risk variants for migraine. Leveraging these results through polygenic risk score analyses identified subgroups of patients likely to respond to triptans (an acute migraine drug), providing the first step toward precision medicine in migraine [Kogelman et al. (2019) Neurology Genetics, 5, e364].

Adolescent Endometriosis: An Update

Endometriosis is the leading pathologic cause of dysmenorrhea and chronic pelvic pain among adolescents. The appearance of endometriosis in adolescents may be different from that in female adults, resulting in delayed recognition and intervention. This article addresses the epidemiology, pathophysiology, clinical presentation, diagnosis, and management of endometriosis in the adolescent.

Shared Molecular Genetic Mechanisms Underlie Endometriosis and Migraine Comorbidity

Observational epidemiological studies indicate that endometriosis and migraine co-occur within individuals more than expected by chance. However, the aetiology and biological mechanisms underlying their comorbidity remain unknown. Here we examined the relationship between endometriosis and migraine using genome-wide association study (GWAS) data. Single nucleotide polymorphism (SNP) effect concordance analysis found a significant concordance of SNP risk effects across endometriosis and migraine GWAS. Linkage disequilibrium score regression analysis found a positive and highly significant genetic correlation (rG = 0.38, P = 2.30 × 10-25) between endometriosis and migraine. A meta-analysis of endometriosis and migraine GWAS data did not reveal novel genome-wide significant SNPs, and Mendelian randomisation analysis found no evidence for a causal relationship between the two traits. However, gene-based analyses identified two novel loci for migraine. Also, we found significant enrichment of genes nominally associated (Pgene < 0.05) with both traits (Pbinomial-test = 9.83 × 10-6). Combining gene-based p-values across endometriosis and migraine, three genes, two (TRIM32 and SLC35G6) of which are at novel loci, were genome-wide significant. Genes having Pgene < 0.1 for both endometriosis and migraine (Pbinomial-test = 1.85 ×10-°3) were significantly enriched for biological pathways, including interleukin-1 receptor binding, focal adhesion-PI3K-Akt-mTOR-signaling, MAPK and TNF-α signalling. Our findings further confirm the comorbidity of endometriosis and migraine and indicate a non-causal relationship between the two traits, with shared genetically-controlled biological mechanisms underlying the co-occurrence of the two disorders.

Migraine in relation with endometriosis phenotypes: Results from a French case-control study

BACKGROUND

Studies have shown a significant association between migraine and endometriosis, but no study has explored the relationship between migraine and endometriosis phenotypes: Superficial peritoneal endometriosis, ovarian endometrioma, and deep infiltrating endometriosis.

METHODS

We conducted a case-control study using data collected from 314 women aged 18 to 42 years who had undergone surgery for benign gynecological conditions between January 2013 and December 2015. All women completed a self-administered headache questionnaire according to the IHS classification. Cases (n = 182) are women with histologically proven endometriosis and controls are women (n = 132) without endometriosis. Occurrence of migraine was studied according to endometriosis phenotypes.

RESULTS

Migraine prevalence in cases was significantly higher compared with controls (35.2% vs. 17.4%, p = 0.003). The risk of endometriosis was significantly higher in migrainous women (OR = 2.62; 95% CI = 1.43-4.79). When we take into account endometriosis phenotypes, the risk of ovarian endometrioma and deep infiltrating endometriosis were significant (OR = 2.78; 95% CI = 1.11-6.98 and OR = 2.51; 95% CI = 1.25-5.07, respectively). In women with endometriosis, the intensity of chronic non-cyclical pelvic pain was significantly greater for those with migraine (visual analogic scale (VAS) = 3.6 ± 2.9) compared with the women without headache (VAS = 2.3 ± 2.8, p = 0.0065).

CONCLUSION

Our study shows a significant association between migraine and endometriosis. In clinical practice, women of reproductive age who suffer from migraine should be screened for endometriosis criteria in order to optimise the medical and therapeutic care of this condition.

Polygenic risk score: use in migraine research

BACKGROUND

The latest Genome-Wide Association Study identified 38 genetic variants associated with migraine. In this type of studies the significance level is very difficult to achieve (5 × 10^- 8) due to multiple testing. Thus, the identified variants only explain a small fraction of the genetic risk. It is expected that hundreds of thousands of variants also confer an increased risk but do not reach significance levels. One way to capture this information is by constructing a Polygenic Risk Score. Polygenic Risk Score has been widely used with success in genetics studies within neuropsychiatric disorders. The use of polygenic scores is highly relevant as data from a large migraine Genome-Wide Association Study are now available, which will form an excellent basis for Polygenic Risk Score in migraine studies.

RESULTS

Polygenic Risk Score has been used in studies of neuropsychiatric disorders to assess prediction of disease status in case-control studies, shared genetic correlation between co-morbid diseases, and shared genetic correlation between a disease and specific endophenotypes.

CONCLUSION

Polygenic Risk Score provides an opportunity to investigate the shared genetic risk between known and previously unestablished co-morbidities in migraine research, and may lead to better and personalized treatment of migraine if used as a clinical assistant when identifying responders to specific drugs. Polygenic Risk Score can be used to analyze the genetic relationship between different headache types and migraine endophenotypes. Finally, Polygenic Risk Score can be used to assess pharmacogenetic effects, and perhaps help to predict efficacy of the Calcitonin Gene-Related Peptide monoclonal antibodies that soon become available as migraine treatment.

Multi-Center Studies of the Global Impact of Endometriosis and the Predictive Value of Associated Symptoms

Introduction

Endometriosis can be difficult to diagnose clinically and models that use symptoms to predict whether the disease is present or not are based on limited patient populations. Endometriosis also influences health-related quality of life, but little is known about its impact across the world. We therefore initiated two integrated multi-center studies to collect prospective, standardized, epidemiological data, to 1) examine the global impact of endometriosis and relative effect of risk-factors, and 2) develop a symptom-based diagnostic tool.

Methods

The Global Study of Women's Health (GSWH) and the Women's Health Symptom Survey (WHSS) prospectively recruit 18–45 year old women having a laparoscopy across 23 and 19 centers, respectively, worldwide. Women with a previous surgical diagnosis of endometriosis are excluded. Multi-lingual patient questionnaires and a surgical questionnaire, incorporating validated instruments, are used to collect the data. The GSWH aims to recruit >2,000 women by December 2009; the WHSS to recruit 1,000 women in each of the two model-generating and validation stages.

Results

A six-week pilot study in Oxford, UK, established the feasibility of the study protocols. Of 32 eligible women, 27 participated (response rate - 84.4%); 26% completed the questionnaire online. Endometriosis was found in 47.4%. Extrapolating the recruitment rates from the pilot study, the target sample sizes for the GWSH and WHSS were deemed feasible.

Conclusions

Using standardized data collection, the GSWH and WHSS will provide insight into the global impact of endometriosis and develop a validated, symptom-based, diagnostic tool. They have the potential to provide the basis for future, longitudinal, follow-up studies and a collaborative Endometriosis Biobank implementing standardized collection of DNA and tissue samples

Protocol of randomized controlled trial of potentized estrogen in homeopathic treatment of chronic pelvic pain associated with endometriosis

BACKGROUND

Endometriosis is a chronic inflammatory disease that causes difficult-to-treat pelvic pain. Thus being, many patients seek help in complementary and alternative medicine, including homeopathy. The effectiveness of homeopathic treatment for endometriosis is controversial due to the lack of evidences in the literature. The aim of the present randomized controlled trial is to assess the efficacy of potentized estrogen compared to placebo in the treatment of chronic pelvic pain associated with endometriosis.

METHODS/DESIGN

The present is a randomized, double-blind, placebo-controlled trial of a homeopathic medicine individualized according to program 'New Homeopathic Medicines: use of modern drugs according to the principle of similitude' (http://newhomeopathicmedicines.com). Women with endometriosis, chronic pelvic pain and a set of signs and symptoms similar to the adverse events caused by estrogen were recruited at the Endometriosis Unit of Division of Clinical Gynecology, Clinical Hospital, School of Medicine, University of São Paulo (Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - HCFMUSP). The participants were selected based on the analysis of their medical records and the application of self-report structured questionnaires. A total of 50 women meeting the eligibility criteria will be randomly allocated to receive potentized estrogen or placebo. The primary clinical outcome measure will be severity of chronic pelvic pain. Statistical analysis will be performed on the intention-to-treat and per-protocol approaches comparing the effect of the homeopathic medicine versus placebo after 24 weeks of intervention.

DISCUSSION

The present study was approved by the research ethics committee of HCFMUSP and the results are expected in 2016.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: https://clinicaltrials.gov/ct2/show/NCT02427386.

The use of progestogen-only pill in migraine patients

Migraine is a debilitating neurovascular disorder which is estimated to affect 18% of women and 6% of men. Two main forms of this neurological disorder must be considered: Migraine without Aura and Migraine with Aura. Migraine without aura often has a strict menstrual relationship: the International Headache Society classification gives criteria for Pure Menstrual Migraine and Menstrually Related Migraine. The higher prevalence of migraine among women suggests that this sex difference probably results from the trigger of fluctuating hormones during the menstrual cycle. Safe and effective contraception is essential for all women of childbearing age, but Combined Oral Contraceptives have been associated with worsening of attacks and cardiovascular risk in these patients. We analyzed characteristics, effects and benefits of progestogen-only pill, a possible alternative for contraception in women with migraine.

Stroke in Young Women

In women ages 15-45 years, an additional set of risk factors are important in the pathogenesis of ischemic stroke. Some of these pertain strictly to women, and relate to exogenous hormones and pregnancy. Various other conditions are more common in women, which include migraine with aura, selected vascular disorders and autoimmune conditions. These differences do have implications for management in both the primary and secondary prevention of stroke in this age group.

Comparing treatments for endometriosis-related pain symptoms in patients with migraine without aura

Endometriosis is a gynecological disorder defined by the presence of endometrial-like tissue outside the uterus. Several studies have found an epidemiological correlation between endometriosis and migraine, probably due to the association of both diseases with female hormones. Progestins or combined oral contraceptives are the first-line medical therapy in women with endometriosis; however, it is well known that in some women the use of combined oral contraceptives could exacerbate migraine. This observation poses a challenge to clinicians who must concomitantly treat endometriosis-related symptoms and migraine. This review summarizes the available literature on the medical treatment of endometriosis in women suffering concomitant migraine without aura until March 2012. Due to the lack of available studies on this topic, it is difficult to draw definitive conclusions. Further studies evaluating hormonal therapies are needed; in particular, progestin therapy should be reconsidered in women with migraine and concomitant endometriosis.

Progestogen-only contraceptive pill compared with combined oral contraceptive in the treatment of pain symptoms caused by endometriosis in patients with migraine without aura

OBJECTIVE

Evaluate patient satisfaction at 6-month treatment in women with symptomatic rectovaginal endometriosis and migraine without aura with (progestogen-only contraceptive pill, POP versus sequential combined oral contraceptives, COC) STUDY DESIGN: A patient preference trial including 144 women (82 in the group COC and 62 in the group POP). Main outcome measure was the degree of patient satisfaction by using a Likert scale. Secondary objectives were to evaluate differences in endometriosis-related pain and changes in migraine features during the treatment.

RESULTS

In group POP, 38/62 women (61.2%) were satisfied or very satisfied after treatment, compared to 31/82 women (37.8%) in group COC (p=0.005). The intensity of chronic pelvic pain and dyspareunia significantly decreased at 6-month treatment in both the groups. At 6-month treatment, the number of migraine attacks was lower than at baseline in group POP (p=0.002), while it was not reduced in group COC (p=0.521). The intensity of migraine attacks was significantly different between baseline and 6-month treatment in group POP (p<0.001) but not in group COC (p=0.078).

CONCLUSIONS

POP is better tolerated than COC and it seems to ameliorate migraine attacks compared to COC in symptomatic patients with rectovaginal endometriosis and migraine without aura. Both drugs efficaciously relieve endometriosis-related pain symptoms. This study supports the use of the POP in women with rectovaginal endometriosis and coexisting migraine without aura.

Insights into Assessing the Genetics of Endometriosis

Endometriosis is a complex disease arising from the interplay between multiple genetic and environmental factors. The genetic variants potentially underlying the hereditary component of endometriosis have been widely investigated through hypothesis-driven candidate gene studies, an approach that generally has proven to be inherently difficult and problematic for a number of reasons. Recently, through major collaborative efforts in the endometriosis research field, hypothesis-free genome-wide approaches have started to provide new insights into potential pathways leading to development of endometriosis, as well as highlighting the phenotypic heterogeneity of the condition. This review summarizes the most recent studies investigating the genetic variation contributing to endometriosis, with a particular focus on genome-wide approaches, and discusses promising future directions of genetic research.

Twin studies of pain

Twin studies provide a method for estimating the heritability of phenotypes and for examining genetic and environmental relationships between phenotypes. We conducted a systematic review of twin studies of pain, including both clinical and experimental pain phenotypes. Fifty-six papers were included, whereof 52 addressed clinical phenotypes. Of the most comprehensively studied phenotypes, available data indicates heritability around 50% for migraine, tension-type headache and chronic widespread pain, around 35% for back and neck pain, and around 25% for irritable bowel syndrome. However, differences in phenotype definitions make these results somewhat uncertain. All clinical studies relied on dichotomous outcomes and none used pain intensity as continuous phenotype. This is a major weakness of the reviewed studies and gives reason to question their validity with respect to pain mechanisms. Experimental pain studies indicate large differences in heritability across pain modalities. Whereas there is evidence for substantial common genetic risk across many clinical pain conditions, different experimental pain phenotypes appear to be associated with different genetic factors. Recommendations for future research include inclusion of pain intensity scaling and number of pain sites in phenotyping. Furthermore, studies examining the genetic relationships between pain phenotypes, in particular between clinical and experimental phenotypes, should be prioritized.

Comorbidity in perimenstrual migraine

Comorbidity may be defined as the association of two or more diseases in individuals at a frequency greater than that expected statistically by chance. Studying the co-occurrence of two disorders requires a careful statistical analysis before any clear conclusion on causality is reached. Many studies have looked for an association between migraine and many diseases, reporting several sometimes controversial comorbidities in migraine subjects. Although migraine is more common in women than in men, very few studies have analyzed the comorbidity of perimenstrual migraine, a migraine sub-type characterized by attacks of migraine without aura related to menstruation. We review the studies on migraine comorbidities, particularly migraine without aura in women.

Women with endometriosis are more likely to suffer from migraines: a population-based study

Previous research suggests that a co-morbid relationship exists between migraine and endometriosis; however, results have been inconsistent. In addition, female hormones, which are important in the pathogenesis and management of endometriosis, have been reported to precipitate migraine attacks and may confound the results. The aim of this population-based cohort study was to explore the relationship between migraine and endometriosis in women of reproductive age (18-51 years). Data were derived from the National Health Insurance Research Database of Taiwan, which contains outpatient and inpatient records from 2000 to 2007. Our study cohort included 20,220 endometriosis patients and 263,767 controls without endometriosis. We analyzed the prevalence of migraine in these women as recorded during the eight years of the database. Our results found that patients with endometriosis were more likely to suffer migraine headaches compared to controls (odds ratio [OR], 1.70; 95% confidence interval [CI] [1.59, 1.82]; p<0.001). In addition, the co-morbid association between migraine and endometriosis remained significant after the data were controlled for age and frequently utilized hormone therapies (OR, 1.37; 95% CI, [1.27, 1.47]; p<0.001). The results of this cohort study support the existence of a co-morbid relationship between migraine and endometriosis, even after adjusting for the possible effects of female hormone therapies on migraine attacks.

Endometriosis and headache

Headache and endometriosis show some similarities in their clinical and epidemiological features that are probably due to the influence of female sexual hormones on both disorders. Epidemiological studies indicate that they are comorbid disorders. However, the nature of the comorbidity is not known with certainty, but a likely explanation may be common susceptibility genes. Another possibility is that, because they both are related to pain, increased pain sensitivity induced by one of the disorders may lead to a higher likelihood of developing the other, possibly mediated by nitrogen oxide or prostaglandins. A common link to the widespread use of estroprogestins may seem less probable. For physicians dealing with women with either of these disorders, awareness of the comorbidity may be helpful in the treatment of the patient.

Migraine and preterm birth

OBJECTIVE

To investigate whether maternal migraine was associated with preterm birth.

STUDY DESIGN

Case-control sample within a population-based study of risk factors for cerebral palsy (CP). Infants without CP were matched for gestational age with those with CP. Maternal migraine was self-identified at first prenatal visit, most in the first trimester.

RESULT

Infants without CP born to women with migraine had a higher rate of preterm birth (odds ratio (OR)=3.5, 95% confidence interval (CI) 1.5, 8.5), as did infants who died in the perinatal period (OR=7.3, 95% CI 0.98, 54), the difference marginal for nominal statistical significance. In all outcome groups, infants of women with migraine had a higher observed rate of suboptimal intrauterine growth. In term infants, the rate of maternal migraine was higher in those with CP than in controls (OR=2.18, 95% CI 0.92, 5.25). Pre-eclampsia was reported more frequently in women with migraine who gave birth to a child with CP or a perinatal death, particularly in those born preterm; OR=5.1 (1.3, 20) and OR=2.9 (1.1, 7.6), respectively, but not in women giving birth to a control whether term or preterm.

CONCLUSION

Maternal migraine, as self-reported early in pregnancy, was associated with preterm birth in survivors without CP and in infants who died in the perinatal period. The combination of maternal migraine and pre-eclampsia was associated with CP and perinatal death. The association of maternal migraine with outcomes of pregnancy warrants further study.

Migraine in women with chronic pelvic pain with and without endometriosis

OBJECTIVE

To examine the prevalence of migraine in women with chronic pelvic pain with and without endometriosis.

DESIGN

Prospective study of headache, pelvic pain, and quality of life before laparoscopic surgery for pelvic pain. Endometriosis was diagnosed pathologically. Headaches were classified as migraine or non-migraine using International Headache Society criteria.

SETTING

Clinical research hospital.

PATIENT(S)

108 women in a clinical trial for chronic pelvic pain (NCT00001848).

INTERVENTION(S)

Laparoscopy to diagnose endometriosis, assessment by neurologist to assess headaches.

MAIN OUTCOME MEASURE(S)

Prevalence of migraine and other headaches in women with chronic pelvic pain with or without endometriosis. Headache frequency, severity and relationship to pelvic pain and endometriosis.

RESULT(S)

Lifetime prevalence of definite or possible migraine was 67% of women with chronic pelvic pain. An additional 8% met criteria for possible migraine. Migraine was no more likely in women with endometriosis than those without. Women with the most severe headaches had a lower quality of life compared with those with pelvic pain alone.

CONCLUSION(S)

Migraine headache is common in women with chronic pelvic pain, regardless of endometriosis, and contributes to disability in those with both conditions. The strong association suggests a common pathophysiology.

Evaluation of polymorphisms in predicted target sites for micro RNAs differentially expressed in endometriosis

Previous microarray analyses identified 22 microRNAs (miRNAs) differentially expressed in paired ectopic and eutopic endometrium of women with and without endometriosis. To investigate further the role of these miRNAs in women with endometriosis, we conducted an association study aiming to explore the relationship between endometriosis risk and single-nucleotide polymorphisms (SNPs) in miRNA target sites for these differentially expressed miRNAs. A panel of 102 SNPs in the predicted miRNA binding sites were evaluated for an endometriosis association study and an ingenuity pathway analysis was performed. Fourteen rare variants were identified in this study. We found SNP rs14647 in the Wolf-Hirschhorn syndrome candidate gene1 (WHSC1) 3'UTR (untranslated region) was associated with endometriosis-related infertility presenting an odds ratio of 12.2 (95% confidence interval = 2.4-60.7, P = 9.03 × 10(-5)). SNP haplotype AGG in the solute carrier family 22, member 23 (SLC22A23) 3'UTR was associated with endometriosis-related infertility and more severe disease. With the individual genotyping data, ingenuity pathways analysis identified the tumour necrosis factor and cyclin-dependant kinase inhibitor as major factors in the molecular pathways. Significant associations between WHSC1 alleles and endometriosis-related infertility and SLC22A23 haplotypes and the disease severe stage were identified. These findings may help focus future research on subphenotypes of this disease. Replication studies in independent large sample sets to confirm and characterize the involvement of the gene variation in the pathogenesis of endometriosis are needed.

Migraine symptomatology and major depressive disorder

Introduction and objective: Migraine and major depressive disorder (MDD) frequently co-occur, but it is unclear whether depression is associated with a specific subtype of migraine. The objective of this study was to investigate whether migraine is qualitatively different in MDD patients ( N = 1816) and non-depressed controls ( N = 3428).

Methods: Migraine symptom data were analyzed using multi-group Latent Class Analysis, and a qualitative comparison was made between the symptom profiles of MDD patients and controls, while allowing for differences in migraine prevalence and severity between groups.

Results: In both groups, three migrainous headache classes were identified, which differed primarily in terms of severity. Both mild and severe migrainous headaches were two to three times more prevalent in MDD patients. Migraine symptom profiles showed only minor qualitative differences in the MDD and non-MDD groups: in the severe migrainous headache class, significant differences were observed only in the prevalence of aggravation by physical activity (83% and 91% for the non-MDD and MDD groups, respectively) and aura (42% vs. 53%, respectively).

Conclusion: The similar overall symptom profiles observed in the MDD and non-MDD subjects suggest that a similar disease process may underlie migraine in both groups.

MULTI-CENTRE STUDIES OF THE GLOBAL IMPACT OF ENDOMETRIOSIS AND THE PREDICTIVE VALUE OF ASSOCIATED SYMPTOMS

INTRODUCTION

Endometriosis can be difficult to diagnose clinically and models that use symptoms to predict whether the disease is present or not are based on limited patient populations. Endometriosis also influences health-related quality of life, but little is known about its impact across the world. We therefore initiated two integrated multicentre studies to collect prospective, standardised, epidemiological data, to 1) examine the global impact of endometriosis and relative effect of risk-factors, and 2) develop a symptom-based diagnostic tool.

METHODS

The Global Study of Women's Health (GSWH) and the Women's Health Symptom Survey (WHSS) prospectively recruit 18-45 year old women having a laparoscopy across 23 and 19 centres, respectively, worldwide. Women with a previous surgical diagnosis of endometriosis are excluded. Multi-lingual patient questionnaires and a surgical questionnaire, incorporating validated instruments, are used to collect the data. The GSWH aims to recruit >2,000 women by December 2009; the WHSS to recruit 1,000 women in each of the two model-generating and validation stages.

RESULTS

A six-week pilot study in Oxford, UK, established the feasibility of the study protocols. Of 32 eligible women, 27 participated (response rate - 84.4%); 26% completed the questionnaire online. Endometriosis was found in 47.4%. Extrapolating the recruitment rates from the pilot study, the target sample sizes for the GWSH and WHSS were deemed feasible.

CONCLUSIONS

Using standardised data collection, the GSWH and WHSS will provide insight into the global impact of endometriosis and develop a validated, symptom-based, diagnostic tool. They have the potential to provide the basis for future, longitudinal, follow-up studies and a collaborative Endometriosis Biobank implementing standardised collection of DNA and tissue samples.