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

Abstract

ObjectiveEndometriosis is considered as a serious gynaecological disease in women at a reproductive age. Lower body mass index (BMI) is thought to be a risk factor. However, recent studies indicated that women with normal BMI were also more likely to develop endometriosis, suggesting the association with BMI is controversial. We therefore investigated the association of BMI and surgically diagnosed endometriosis in a cohort of Chinese women.DesignRetrospective case–control study.SettingTertiary hospital.Patients709 women with endometriosis and 807 age matched controls between January 2018 and August 2019.InterventionAge at diagnosis, parity, gravida, BMI and self-reported dysmenorrhoea status were collected and the association of BMI and endometriosis was analysed.Measurement and main resultsOverall, the median BMI was not different between patients and controls (21.1 kg/m2 vs 20.9 kg/m2, p=0.223). According to the BMI categories for Asians/Chinese by WHO (underweight: <18.5 kg/m2, normal weight: 18.5–22.99 kg/m2, overweight: 23–27.49 kg/m2, obese: ≥27.50 kg/m2), overall, there was no difference in the association of BMI and endometriosis (p=0.112). 60% of patients were of normal weight. However, the OR of obese patients (BMI over 27.50 kg/m2) having endometriosis was1.979 (95% CI 1.15 to 3.52, p=0.0185), compared with women with normal weight. 50.3% patients reported dysmenorrhoea, and the OR of developing severe dysmenorrhoea in obese patients (BMI over 27.50 kg/m2) was 3.64 (95% CI 1.195 to 10.15, p=0.025), compared with patients with normal weight.ConclusionOur data demonstrate that overall there was no association between BMI and the incidence of endometriosis, but there was a significant increase in the incidence of endometriosis in obese women, compared with women with normal weight. Obesity was also a risk factor for severe dysmenorrhoea.

Endometriosis and Risk of Adverse Pregnancy Outcome: A Systematic Review and Meta-Analysis

“…A priori, based on directed Acyclic graphs (DAGs) and the existing literature, we selected the following relevant potential confounding factors: maternal age, smoking, body mass index (BMI), and socioeconomic status. These factors have been shown to be associated with endometriosis [ 14 , 15 , 16 ] and increase the risk of several adverse pregnancy outcomes [ 17 , 18 , 19 , 20 ]. Thus, we considered these the most important potential confounders.…”

Endometriosis: Epidemiology, Classification, Pathogenesis, Treatment and Genetics (Review of Literature)

“…Interestingly, the latest data indicate that there is generally no association between BMI and the incidence of endometriosis, but there has been a significant increase in the incidence of endometriosis in obese women compared to women with normal body weight. Obesity is also a risk factor for severe dysmenorrhea [ 50 ].…”

The Relationship between Age of Menarche and Body Mass Index (BMI) with Endometriosis Incidence at Dr. Mohammad Hoesin Palembang Period 2018 – 2020

“…11,12 According to Sampson's theory, the incidence of endometriosis can be caused by menstrual reflux whereas women who have more menstrual opportunities will be more at risk for experiencing endometriosis. 13 Women with early age of menarche (<12 years) will be exposed to estrogen longer and the possibility of menstrual reflux will be greater, thus increasing the risk of endometriosis. 7 In the body mass index (BMI) variable, the p-value obtained in this study was 1.000 which means that there is no statistically significant relationship between body mass index (BMI) and obesity category (BMI 25) on the incidence of endometriosis in Dr. Mohammad…”