RACE/ETHNICITY-SPECIFIC ASSOCIATIONS BETWEEN SMOKING, SERUM LEPTIN, AND ABDOMINAL FAT: THE MULTI-ETHNIC STUDY OF ATHEROSCLEROSIS

Objective: Smoking is a well-known cardiovascular risk factor associated with weight loss. We aimed to evaluate the association between smoking, serum leptin levels, and abdominal fat. Design: Cross-sectional Setting: Data from examinations 2 or 3 (2002-2005) of the Multi-Ethnic Study of Atherosclerosis (MESA) Participants: 1,875 asymptomatic, community-dwelling adults Main Outcomes Measures: We used multivariable linear regression models to assess the race/ethnicity-specific associations between smoking, serum log(e)-leptin levels, and computed tomography ascertained abdominal fat. Results were adjusted for demographic and relevant clinical covariates. Results: Participants (mean age 64.5 +/- 9.6 years; 50.6% women; 42.2% former, 11.4% current smokers) were White (40.1%), Hispanic (25.8%), African American (21.1%), and Chinese (13.0%). Overall, median (25th - 75th percentile) leptin levels were significantly lower among current (11.14 ng/mL; 4.13 - 26.18) and former smoke's (11.68 ng/mL; 4.72 - 27.57), as compared with never smokers (15.61 ng/mL; 3.05 - 30.12) (P<.001). The difference in median leptin levels between current and never smokers were significantly higher for Hispanics (Delta 9.64 ng/mL) and African Americans (Delta 8.81 ng/mL) than Whites (Delta 2.10 ng/mL) and Chinese (Delta 4.70 ng/mL) (P<.001). After adjustment for total abdominal fat, log(e)-leptin levels remained lower for former (-.14 [-.22 - -.07]) and current (-.17[-.28 - -.05]) smokers, compared with never smokers. Results differed by race/ethnicity, with significantly lower log(e)-leptin levels observed only among current and former African Americans and Hispanic smokers, compared with their never smoker counterparts. (Ps for interaction <.05) Conclusions: Among smokers, leptin levels significantly vary by race/ethnicity. Former and current smoking are associated with lower leptin levels, although this may be restricted to Hispanics and African Americans.