Associations between smoking and lipid/lipoprotein concentrations among US adults aged ≥20 years

Cross-sectional data from National Health and Nutrition Examination Survey for the years 1999–2012 for those aged ≥20 years, fasting for at least 8 h, and classified as smokers and nonsmokers on the basis of observed serum cotinine levels were used to evaluate the impact of smoking on the adjusted and unadjusted concentrations of low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, total cholesterol (TC), and triglycerides (TG). Adjustments were made for the effects of gender; race/ethnicity; survey year; dietary intake of alcohol; caffeine; cholesterol; saturated, unsaturated, and total fatty acids; fasting time; body mass index; and poverty income ratio. Adjusted levels of LDL and TC did not vary among smokers and nonsmokers. Smokers had lower adjusted levels of HDL than nonsmokers (48.8 vs. 51.4 mg/dL, p < 0.01) and higher adjusted levels of TG (124.4 vs. 111.9 mg/dL, p < 0.01) than nonsmokers. Adjusted odds of smokers having abnormal levels were 1.6 (95% confidence interval (CI) 1.4–1.8) for HDL, 1.2 (95% CI 1.1–1.4) for TC, and 1.3 (95% CI 1.2–1.5) for TG. Males had lower adjusted levels than females for HDL (45.2 vs. 55.4 mg/dL, p < 0.01) and TC (191.3 vs. 196.6 mg/dL, p < 0.01) but higher adjusted levels than females for TG (126.3 vs. 110.1 mg/dL, p < 0.01) and LDL (114.4 vs. 112.6 mg/dL, p = 0.02). A unit increase in body mass index was associated with 1.4% decrease in the adjusted levels of HDL, 0.18% increase in the adjusted levels of LDL, and a 2.3% increase in the adjusted levels of TG.