Lesbian and bisexual women aged 40 years or younger are more than twice as likely to develop type 2 diabetes vs. heterosexual women, with BMI likely influencing the risk, according to an analysis of Nurses’ Health Study II data.
“Despite inconclusive findings, there is a reason to suspect that [lesbian and bisexual] women may have disparities in chronic physical health conditions, including type 2 diabetes, because they are more likely than heterosexual women to have risk factors such as obesity, tobacco smoking, heavy alcohol drinking and stress-related exposures,” Heather L. Corliss, MPH, PhD, professor in the division of health promotion and behavioral science at San Diego State University Graduate School of Public Health, and colleagues wrote in the study background. “Minority stress is theorized to be a central reason why [lesbian and bisexual] women are at elevated risk for physical health problems including type 2 diabetes.”
Corliss and colleagues analyzed data from 94,250 women participating in the Nurses’ Health Study II, a prospective cohort of female nurses established in 1989. The cohort included 1,267 women who self-identified as lesbian or bisexual and 92,983 women who identified as heterosexual (average age during follow-up, 46 years; 95% white). Researchers assessed type 2 diabetes incidence every other year via biennial questionnaires and used Cox proportional hazard models to examine the association between sexual orientation and incidence of type 2 diabetes.
During follow-up through 2013, 6,399 women developed type 2 diabetes.
In unadjusted models, lesbian and bisexual women had a 22% greater risk for developing type 2 diabetes vs. heterosexual women, with the risk persisting after adjustment for family history of diabetes, race, rural status and menopausal status (incidence rate ratio [IRR] = 1.27; 95% CI, 1.05-1.54). However, any risk was attenuated in mediation analysis when BMI was added to the model, according to researchers.
Researchers also observed an interaction between diabetes incidence and age (P = .0007). In lesbian and bisexual women aged 40 years or younger, incidence of type 2 diabetes was more than twice as high as for heterosexual women of the same age range after adjustment for confounders (IRR = 2.44; 95% CI, 1.54-3.86). This risk fell for lesbian and bisexual women aged 40 to 49 years (IRR = 1.36; 95% CI, 1.02-1.81) and did not rise to significance for lesbian and bisexual women aged 50 to 68 years (IRR = 0.96; 95% CI, 0.7-1.31). However, further adjustment for BMI attenuated all associations observed in younger women, according to the researchers.
“Our study found that greater BMI along [lesbian and bisexual] women prospectively explained their elevated risk for type 2 diabetes,” the researchers wrote. “This finding helps to establish the critical role for obesity in contributing to [lesbian and bisexual] women’s greater risk for developing type 2 diabetes.”
“A better understanding of disease management challenges [lesbian and bisexual] women experience after diagnosis is also needed to help reduce the clinical burden of type 2 diabetes complications,” the researchers wrote. – by Regina Schaffer
Disclosures: The National Institute of Diabetes and Digestive and Kidney Diseases supported this study. The authors report no relevant financial disclosures.