Findings from a epidemiological study conducted by a research team from The University of Tokushima Graduate School in Japan indicate that women with endometriosis confirmed by surgery and also those women who were diagnosised with imaging without surgery have common risk profiles, however, these risk profiles are different from those found in women with adenomyosis. According to the researchers, clinicians should consider the presence of a history of infertility for evaluation of risk profiles. The study was recently published in the Journal of Epidemiology.
Endometriosis is a condition that causes the presence of endometrial-like tissue outside the uterine cavity and is associated with symptoms of dysmenorrhea, dyspareunia, chronic pain, and infertility. The estimated prevalence of endometriosis varies by population. Most of the epidemiological studies on the prevalence and risk factors of endometriosis have been based on clinically diagnosed endometriosis, self-reported physician-diagnosed endometriosis without confirmation by a surgical procedure may be substantially misclassified.
An invasive procedure and histological examination are needed for a definitive diagnosis of endometriosis but are not performed for women with minimal or mild endometriosis who have no symptoms. Studies are unable to assess risks of occurrence of endometriosis-related diseases when the endometriosis has been treated by a surgical procedure. Therefore, a validated method of diagnosing endometriosis using non-invasive imaging is needed. It has been reported that the sensitivity and specificity of MRI relative to histologically confirmed endometriosis were 69% and 75%, respectively, and that the sensitivity of MRI was 76.9% for endometriosis detected by laparoscopy.
Endometriosis causes infertility with dysmenorrhea, pelvic pain, and dyspareuria in women of reproductive age. Therefore, infertility status should be considered in epidemiological studies on endometriosis.
To clarify the differences in prevalence and risk factors for endometriosis between surgically confirmed endometriosis and imaging-diagnosed endometriosis, in the study titled “ Risk Profiles for Endometriosis in Japanese Women: Results from a Repeated Survey of Self-Reports,” Toshiyuki Yasui from the Department of Reproductive Technology, Institute of Health Biosciences, and colleagues compared risk profiles in imaging-diagnosed endometriosis with and without a surgical procedure in a large population of Japanese women, and also looked at differences in risk profiles of endometriosis according to the presence of a history of infertility.
A total of 1,025 women were evaluated via self-reported questionnaires in order to assess their endometriosis status. Questionnaires included items on sites of endometriosis determined by imaging techniques and surgical procedure. All women were taking part of the Japan Nurses’ Health Study survey (n = 15 019), a large prospective cohort study designed to investigate the effects of lifestyle and healthcare practices on the health of Japanese women.
Results revealed that a total of 210 women had surgically confirmed endometriosis (Group A), 120 had imaging-diagnosed endometriosis without a surgical procedure (Group B), and 264 had adenomyosis (Group C).
The researchers found that a short menstrual cycle at 18–22 years of age and cigarette smoking at 30 years of age were associated with a higher risk of endometriosis both in those women in Group A and those in group Group B, while older age was associated with risk of adenomyosis in women in Group C. In women with a history of infertility, a short menstrual cycle was associated with a higher risk of endometriosis in both Group A and Group B, but risk profiles of endometriosis were different between Group A and Group B in women without a history of infertility.
Based on these results, the team of researchers believe that women with surgically confirmed endometriosis and those with imaging-diagnosed endometriosis without surgery have basically common risk profiles and may be used as the same disease entity for an epidemiological survey. However, according to the researchers, in women without a history of infertility, it is necessary to pay attention to the differences in indication and preference for surgery according to background characteristics.