Introduction: Smoking, a well-known cardiometabolic risk factor, is the leading cause of preventable death worldwide. We aimed to evaluate the association between smoking and serum leptin levels, and the influence of abdominal fat in this relationship.
Methods: In this cross-sectional study, we studied 1,875 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) examinations 2 or 3 (2002-2005) with available data on smoking status and leptin levels. We used multivariable linear regression models to assess the race/ethnicity-specific associations between smoking, and serum leptin, and computed tomography-measures of abdominal fat. Results were adjusted for demographic and clinical covariates.
Results: Participants (mean age 64.5±9.6; 49.4% men; 42.2% former, 11.4% current smokers) were White (40.1%), Hispanic (25.8%), African (21.1%), and Chinese (13.0%) Americans. Overall, median leptin levels were significantly lower in current smokers (11.14, interquartile range [IQR] 4.13 – 26.18 ng/mL) and former smokers (11.68, IQR 4.72 - 27.57 ng/mL) compared to never smokers (15.61, IQR 7.04 – 30.11 ng/mL) (P<0.001). The difference in median leptin levels between current and never smokers were significantly higher for Hispanics (Δ9.64 ng/mL) and African Americans (Δ8.81 ng/mL) than Whites (Δ2.10 ng/mL) and Chinese Americans (Δ4.70 ng/mL) (P<0.001). After adjustment for body mass index, waist circumference, and visceral fat, loge-transformed leptin levels remained lower for current smokers, compared to never smokers. Results differed by race/ethnicity, with significantly lower leptin levels among Hispanic former smokers (P for interaction = 0.004) and African American current smokers (P for interaction = 0.008) compared to their never smoker counterparts. (Table)
Conclusions: Smoking is associated with lower leptin levels even after adjusting for measures of abdominal fat, particularly among Hispanics and African Americans.