The effects of cessation from cigarette smoking on the lipid and lipoprotein profiles: a meta-analysis

Background Cross-sectional studies revealed that cigarette smokers have lower high-density lipoprotein cholesterol (HDL-C) levels and higher levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) than nonsmokers. But prospective studies on the effects of cigarette smoking cessation on lipid profile have yielded inconclusive results. Methods Relevant English articles were retrieved by keyword searches of MEDLINE (1966–October 2000), Cochrane Library (2000, Issue 2), and cited references. Twenty-seven studies met the following inclusion criteria: (1) prospective cohort study including clinical trials, (2) measuring smoking status and lipid profile of HDL-C, TC, LDL-C, and TG, (3) reporting the changes of lipid concentrations in abstinent smokers, and (4) not using adjuvant antihyperlipidemic drugs. Results Overall Q statistics for net change of HDL-C, TC, LDL-C, and TG showed heterogeneity. Using a random-effects model, HDL-C level increased significantly {0.100 (CI 0.074 to 0.127) mmol/L} after smoking cessation. However, levels of TC {+0.003 (CI −0.042 to 0.048)}, LDL-C {−0.064 (CI −0.149 to 0.021), and TG {+0.028 (CI −0.014 to 0.071)} did not change significantly after smoking cessation. Conclusions Cigarette smoking cessation increases serum levels of HDL-C but not of TC, LDL-C, and TG.