Respiratory infections are prevalent in the elderly, resulting in increased morbidity, mortality, and utilization of health care services. Vitamin E supplementation has been shown to improve immune response in the elderly. However, the clinical importance of these findings has not been determined.
To investigate the effect of 1-year vitamin E supplementation on respiratory infections in elderly nursing home residents
A randomized, double-blind, placebo-controlled trial conducted from April 1998 to August 2001
33 long-term care facilities in the Boston, Massachusetts area
617 subjects ≥65 years old, who met the study’s eligibility criteria were enrolled, 73% of whom completed the study. The follow-up time (mean ± SD) was 317±104 and 321±97 days, E and placebo respectively, for all subjects enrolled in the study.
A daily vitamin E (200 IU) or placebo capsule; all subjects received a capsule containing 1/2 the Recommended Daily Allowance of essential vitamins and minerals.
Main Outcome Measures
Incidence, number of subjects and number of days with respiratory infections (upper and lower), and number of new antibiotic prescriptions.
There was no statistically significant effect of vitamin E on incidence or number of days with infection for all, upper, or lower respiratory infections. However, fewer vitamin E-supplemented subjects acquired one or more respiratory infections (65% vs 74%, risk ratio=0.88, 95% CI=0.75–0.99, p=0.036 for completed subjects; 60% vs 68%, risk ratio=0.88, 95% CI=0.76–1.00, p=0.048 for all subjects), or upper respiratory infections (50% vs 62%, risk ratio = 0.81, 95% CI=0.66–0.96, p=0.013 for completed subjects; 44% vs 52%, risk ratio=0.84, 95% CI=0.69–1.00, p=0.051 for all subjects). Post hoc sub-group analysis on common colds indicated that the vitamin E group had a lower incidence of common cold (0.66 vs 0.83 per subject-year, rate ratio=0.80, 95% CI=0.64–0.98, p=0.035 for completed subjects; 0.67 vs 0.81 per subject-year, rate ratio=0.83, 95% CI=0.68–1.01, p=0.057 for all subjects) and fewer subjects in the vitamin E group acquired one or more colds (46% vs 57%, risk ratio=0.80, 95% CI=0.64–0.96, p=0.016 for completed subjects; 40% vs 48%, risk ratio=0.83, 95% CI=0.67–1.00, p=0.052 for all subjects). There was no statistically significant vitamin E effect on antibiotic use.
Supplementation with 200 IU per day vitamin E did not have a statistically significant effect on lower respiratory infections in elderly nursing home residents. However, we observed a protective effect of vitamin E supplementation on upper respiratory infections, particularly the common cold, that merits further investigation.