Abstract
BACKGROUND: Vitamin E has influenced the immune system in laboratory studies. Dozens of animal experiments have found that vitamin E offered protection against infections caused by viruses and bacteria. Previously, significant heterogeneity was found in the effect of vitamin E supplementation on pneumonia in humans. The aim of this study was to examine how the effect of vitamin E on pneumonia risk depends on age. METHODS: Secondary analysis of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention study in Finland, 1985-1993, was performed. Participants were male smokers aged 50-69 years at the baseline who started to smoke at ≥21 years (N=7,469). Intervention was 50 mg/d of vitamin E for 5-8 years. The outcome was the incidence of hospital-treated, community-acquired pneumonia by the age at the follow-up. RESULTS: Among 2,216 participants who smoked 5-19 cigarettes per day at baseline and exercised at leisure time, vitamin E supplementation reduced the incidence of pneumonia by 69% (95% confidence interval [CI]: 43%-83%; 57 pneumonia cases). In this subgroup, vitamin E prevented pneumonia in 12.9% of participants by the age of 74 years. Among 5,253 participants who smoked ≥20 cigarettes per day at baseline or did not exercise, the incidence of pneumonia was 14% lower in the vitamin E participants (95% CI: -38% to +21%; 139 cases). One-third of the participants quit smoking for a period, of whom 27 got pneumonia. The incidence of pneumonia was 72% (95% CI: 31%-89%) lower in the vitamin E group, and this benefit was also seen among those males who smoked ≥20 cigarettes per day at baseline or did not exercise. CONCLUSION: Although the evidence of benefit from vitamin E against pneumonia in elderly males is strong in this analysis, the overall findings about vitamin E have been complex. Further research on vitamin E in nonsmoking elderly males is warranted.