Lipids and pulmonary function in the Third National Health and Nutrition Examination Survey

Studies considering the association between total cholesterol and noncardiovascular mortality, particularly from respiratory disease, yield inconclusive findings. To explore this question, the relation of lipids to pulmonary function, specifically forced expiratory volume in 1 second (FEV₁), was investigated in the Third National Health and Nutrition Examination Survey. Conducted in the United States in 1988-1994 among adults aged ≥17 years, this survey measured serum lipids, FEV₁, and confounding factors including smoking and antioxidants. Multiple linear regression analysis explored the relation of FEV₁/height² to low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, and their respective apolipoproteins (apo) B and A-I. A standard deviation increase in HDL cholesterol or apo A-I was associated with an FEV₁ increase of 43 ml (95% confidence interval (Cl): 30, 56) or 29 ml (95% Cl: 11, 47), respectively, for an average-height adult. A standard deviation increase in LDL cholesterol or apo B was associated with an FEV₁ decrease of -24 ml (95% Cl: -43, -5) or -53 ml (95% Cl: -74, -32), respectively, adjusted for serum antioxidant status. The lipid subfractions were differentially associated with FEV₁ consistent with the possibility that LDL cholesterol contributes to endogenous oxidative burden while HDL cholesterol attenuates inflammatory tissue damage. Whether these associations are causal remains to be determined.