About 10% of American women suffer from endometriosis. Over the years, many researchers have tried to understand what causes the condition and what risk factors to look for.
Endometriosis is more common in lower-BMI women
A number of large studies have concluded that thinner women (those with a lower body mass index, or BMI), are more likely to have endometriosis than heavier women.
It is also true that women who were thinner at age 18 have a higher risk of endometriosis, even if they have gained weight over the years. The connection is especially high for women who have been trying for a year or more to get pregnant (the medical point where doctors consider a woman to be struggling with infertility).1
It is important to note that even though endometriosis is less common among obese women, being very overweight is not good for your health. As one study author noted, “The study does not suggest that the morbidly obese women are, in some way, healthier than the lean women and that is the reason for their lower risk of endometriosis. It is more likely that factors related to infertility, which is more common among the very obese, are linked to the reduced risk of endometriosis.”2
Endometriosis is more severe among obese women
A recent study looked for a connection between the severity of endometriosis and body mass index. This study was slightly different from previous ones, because the researchers were operating on the participants and could assess how serious the disease was.3
The researchers confirmed that thinner women did, in fact, have more endometriosis than overweight or obese women. However, the new information in this study was that heavier women had more severe disease than thinner women. Researchers and doctors still don’t understand why or how body mass index affects endometriosis, but knowing a woman’s BMI might help to predict if she is more likely to get severe disease.3
Liu Yong and Zhang Weiyuan. Association between body mass index and endometriosis risk: a meta-analysis. Oncotarget. 2017 Jul 18; 8(29): 46928-46936.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5564533/ Accessed July 1, 2018.
Cole Petrochko. Endometriosis Risk Higher with Lower BMI. MedPage Today. May 14, 2013. https://www.medpagetoday.com/obgyn/generalobgyn/39127 Accessed July 1, 2018.
Sarah Holdsworth-Carson, Uri Dior, Eliza Colgrave, et al., The association of body mass index with endometriosis and disease severity in women with pain. Journal of Endometriosis and Pelvic Pain Disorders. Article first published online: May 27, 2018; Issue published: June 1, 2018. Volume: 10 issue: 2, pages: 79-87. http://journals.sagepub.com/doi/10.1177/2284026518773939 Accessed July 1, 2018.