Vitamin and Micronutrient Intake and the Risk of Community-acquired Pneumonia in US Women

Background: There are limited data regarding the role of dietary and supplemental vitamin intake and the risk of community-acquired pneumonia.

Methods: We prospectively examined, during a 10-year period, the association between dietary and supplemental vitamin intake and the risk of community-acquired pneumonia among 83,165 women in Nurses' Health Study II who were between the ages of 27 and 44 years in 1991. We excluded women who had pneumonia before 1991, those who did not provide complete dietary information, or those with a history of cancer, cardiovascular disease, or asthma. Self-administered food frequency questionnaires were used to assess dietary and supplemental vitamin intake. Cases of pneumonia required a diagnosis by a physician and confirmation with a chest radiograph. The independent associations between specific vitamins and pneumonia risk were evaluated.

Results: There were 925 new cases of community-acquired pneumonia during 650,377 person-years of follow up. After adjusting for age, cigarette smoking, body mass index, physical activity, total energy intake, and alcohol consumption, there were no associations between dietary or total intake of any individual vitamin and risk of community-acquired pneumonia. Specifically, women in the highest quintile of vitamin A intake did not have a significantly lower risk of pneumonia than women in the lowest quintile (multivariate relative risk [RR]=0.88; 95% confidence interval [CI], 0.70-1.09, P for trend=.16). Similarly, vitamin C (RR=0.94; 95% CI, 0.76-1.16, P for trend=.81) and E (RR=0.95; 95% CI, 0.76-1.17, P for trend=.74) intake did not alter risk of pneumonia.

Conclusions: Higher vitamin intake from diet and supplements is unlikely to reduce pneumonia risk in well nourished women.