Context Respiratory tract infections are prevalent in elderly individuals, resulting
in increased morbidity, mortality, and use of health care services. Vitamin
E supplementation has been shown to improve immune response in elderly persons.
However, the clinical importance of these findings has not been determined.
Objective To determine the effect of 1 year of vitamin E supplementation on respiratory
tract infections in elderly nursing home residents.
Design, Setting, and Participants A randomized, double-blind, placebo-controlled trial was conducted from
April 1998 to August 2001 at 33 long-term care facilities in the Boston, Mass,
area. A total of 617 persons aged at least 65 years and who met the study's
eligibility criteria were enrolled; 451 (73%) completed the study.
Intervention Vitamin E (200 IU) or placebo capsule administered daily; all participants
received a capsule containing half the recommended daily allowance of essential
vitamins and minerals.
Main Outcome Measures Incidence of respiratory tract infections, number of persons and number
of days with respiratory tract infections (upper and lower), and number of
new antibiotic prescriptions for respiratory tract infections among all participants
randomized and those who completed the study.
Results Vitamin E had no significant effect on incidence or number of days with
infection for all, upper, or lower respiratory tract infections. However,
fewer participants receiving vitamin E acquired 1 or more respiratory tract
infections (60% vs 68%; risk ratio [RR], 0.88; 95% confidence interval [CI],
0.76-1.00; P = .048 for all participants; and 65%
vs 74%; RR, 0.88; 95% CI, 0.75-0.99; P = .04 for
completing participants), or upper respiratory tract infections (44% vs 52%;
RR, 0.84; 95% CI, 0.69-1.00; P = .05 for all participants;
and 50% vs 62%; RR, 0.81; 95% CI, 0.66-0.96; P =
.01 for completing participants). When common colds were analyzed in a post
hoc subgroup analysis, the vitamin E group had a lower incidence of common
cold (0.67 vs 0.81 per person-year; RR, 0.83; 95% CI, 0.68-1.01; P = .06 for all participants; and 0.66 vs 0.83 per person-year; RR,
0.80; 95% CI, 0.64-0.98; P = .04 for completing participants)
and fewer participants in the vitamin E group acquired 1 or more colds (40%
vs 48%; RR, 0.83; 95% CI, 0.67-1.00; P = .05 for
all participants; and 46% vs 57%; RR, 0.80; 95% CI, 0.64-0.96; P = .02 for completing participants). Vitamin E had no significant
effect on antibiotic use.
Conclusions Supplementation with 200 IU per day of vitamin E did not have a statistically
significant effect on lower respiratory tract infections in elderly nursing
home residents. However, we observed a protective effect of vitamin E supplementation
on upper respiratory tract infections, particularly the common cold, that
merits further investigation.