Smoking, lipids and lipoproteins in Jerusalem 17-year-olds

The relationship between smoking and plasma lipids and lipoproteins was examined in a sample of 17-yr-old participants in the Jerusalem Lipid Research Clinic Study. Of the 669 boys and 571 girls, 31% and 19%, respectively, were current smokers. Smoking prevalence was highest among males of North African origin (48%), and lowest in female of European origin (13%). A two-way analysis of covariance, adjusting for the Quetelet index, triceps skinfold thickness, alcohol intake, social class and father's place of origin, showed that in males, total plasma cholesterol was significantly lower in smokers than in nonsmokers (129 vs. 135 mg/dl, P = 0.010) and that the same pattern was evident in females (145 vs 151 mg/dl, P = 0.054). High-density lipoprotein-cholesterol (HDL-C) was significantly lower in smokers than in nonsmokers, in both males and females (39.6 vs. 42.0 mg/dl, P = 0.004 and 43.9 vs. 48.4 mg/dl, P < 0.001, respectively). There was an inverse linear relationship of HDL-C with the number of cigarettes smoked in both sexes, which was stronger (and statistically significant) in females. HDL-C levels were 17% lower in females and 8% lower in males who smoked ≥ 20 cigarettes per day than in the nonsmokers. Values of low-density lipoprotein-cholesterol (LDL-C) were slightly lower in smokers than in nonsmokers, for both males (74.9 vs. 77.7 mg/dl, P = 0.125) and females (83.7 vs 86.6 mg/dl, P = 0.28). Adjusting also for sex, the differences between smokers and nonsmokers approached conventional levels of statistical significance (P = 0.053). Although males of European origin showed a reverse association to that of males in the other origin groups, no statistically significant interaction for LDL-C was found between father's place of origin and smoking. In female smokers, triglyceride levels were higher (83.8 vs. 74.3 mg/dl, P = 0.014), and very low-density lipoprotein-cholesterol (VLDL-C) was also slightly higher than in nonsmokers (P = 0.091). In males, there was a significant smoking-ethnic group interaction for both triglycerides and VLDL-C, with lower levels in smokers in the Asian origin group, while the Israeli, European and North African origin groups showed the reverse.