Obesity and Weight Gain in Relation to Incidence of Sarcoidosis in US Black Women Data From the Black Women's Health Study

BACKGROUND: Sarcoidosis, a systemic disorder characterized by chronic granulomatous inflammation, occurs more frequently among US black women, as do overweight and obesity. Little is known about the relation of overweight and obesity, which induce chronic inflammation, to incidence of sarcoidosis. METHODS: We assessed the relation of obesity and weight gain to the incidence of sarcoidosis in the Black Women's Health Study, a follow-up study of 59,000 US black women aged 21 to 69 years at baseline in 1995. Information on weight at age 18 years, height, current weight, incident sarcoidosis, and covariates was collected at baseline and on biennial follow-up questionnaires. Cox regression models adjusted for age, education, geographic region, smoking, alcohol consumption, and physical activity were used to estimate incidence rate ratios (IRRs) and 95% CIs. RESULTS: From 1995 through 2011, 454 incident cases of sarcoidosis occurred during 707,557 person-years of follow-up. The incidence of sarcoidosis increased with increasing BMI and weight gain. The IRR was 1.40 (95% CI, 0.88-2.25) for BMI >= 30 kg/m(2) at age 18 years relative to 20 to 24 kg/m(2) (P trend = .18), 1.42 (95% CI, 1.07-1.89) for BMI >= 35 kg/m(2) at baseline relative to 20 to 24 kg/m(2) (P trend = .01), and 1.47 (95% CI, 1.10-1.97) for a weight gain between age 18 years and baseline of >= 30 kg relative to 0 to 9 kg (P trend = .16). In stratified analyses, there were significant trends of sarcoidosis incidence with increasing BMI and weight gain in women aged >= 45 years and ever smokers. CONCLUSIONS: The present study provides evidence that weight gain and obesity during adulthood are associated with increased sarcoidosis incidence.