Fatty acid intake and the risk of community-acquired pneumonia in U.S. women.

OBJECTIVE: Despite substantial progress in the treatment of community-acquired pneumonia, there are limited data on dietary risk factors. Fatty acid intake may influence community-acquired pneumonia risk by modulating the immune system. Our study prospectively examined the association between fatty acid intake and community-acquired pneumonia risk.
METHODS: The study population included 83165 women from the Nurses' Health Study II cohort who were 27 to 44 y old in 1991. The women reported lifestyle habits on biennial questionnaires and dietary intake every 4 y by validated semiquantitative food frequency questionnaires. There were 925 pneumonia cases over 10 y of follow-up. We examined independent associations for six fatty acids using Cox's proportional hazards regression.
RESULTS: Women in the highest quintile of palmitic acid intake had a 54% greater risk of pneumonia compared with those in the lowest quintile (multivariate relative risk 1.54, 95% confidence interval 1.12-2.12, P for trend = 0.002). Oleic acid intake was inversely associated with pneumonia risk (highest quintile multivariate relative risk 0.75, 95% confidence interval 0.55-1.04, P for trend = 0.02). Women in the highest quintile of docosahexanoic acid and eicosapentaenoic acid intake had a 24% greater risk of community-acquired pneumonia than did those in the lowest quintile (multivariate relative risk 1.24, 95% confidence interval 1.00-1.55, P for trend = 0.08). No significant associations were found for linoleic acid, alpha-linolenic acid, or docosahexanoic acid alone.
CONCLUSION: Fatty acid intake may affect the risk of community-acquired pneumonia in young and middle-aged women. Higher dietary intake of palmitic acid and possibly docosahexanoic and eicosapentaenoic acids may increase the risk of community-acquired pneumonia in women, whereas higher oleic acid intake may decrease the risk.