Abstract
BACKGROUND: COPD is the third leading cause of death in the United States. Cigarette smoking accelerates the age-related forced expiratory volume in 1 s (FEV(1)) decline, an important determinant for the genesis of COPD. Hispanic smokers have lower COPD prevalence and FEV(1) decline than non-Hispanic whites (NHWs). PATIENTS AND METHODS: A nutritional epidemiological study was conducted in the Lovelace Smokers cohort (LSC; n=1,829) and the Veterans Smokers cohort (n=508) to identify dietary nutrients (n=139) associated with average FEV(1) and its decline and to assess whether nutrient intakes could explain ethnic disparity in FEV(1) decline between Hispanics and NHW smokers. RESULTS: Nutrients discovered and replicated to be significantly associated with better average FEV(1) included magnesium, folate, niacin, vitamins A and D, eicosenoic fatty acid (20:1n9), eicosapentaenoic acid (20:5n3), docosapentaenoic acid (DPA; 22:5n3), docosahexaenoic acid (22:6n3), and fiber. In addition, greater intakes of eicosenoic fatty acid and DPA were associated with slower FEV(1) decline in the LSC. Among omega 3 polyunsaturated fatty acids, DPA is the most potent nutrient associated with better average FEV(1) and slower FEV(1) decline. Adverse effect of continuous current smoking on FEV(1) decline was completely negated in LSC members with high DPA intake (>20 mg/day). Slower FEV(1) decline in Hispanics compared to NHWs may be due to the greater protection of eicosenoic fatty acid and DPA for FEV(1) decline rather than greater intake of protective nutrients in this ethnic group. CONCLUSION: The protective nutrients for the preservation of FEV(1) in ever smokers could lay foundation for designing individualized nutritional intervention targeting "optimal physiological levels" in human to improve lung function in ever smokers. Ethnic disparity in FEV(1) decline may be explained by difference in magnitude of protection of dietary intakes of eicosenoic fatty acid and DPA between Hispanics and NHWs.