Vitamin E and respiratory tract infections in elderly nursing home residents: a randomized controlled trial.
BACKGROUND
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.


METHODS
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.


METHODS
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.


METHODS
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.
Meydani
Simin Nikbin
SN
Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Mass 02111, USA. simin.meydani@tufts.edu
Leka
Lynette S
LS
Fine
Basil C
BC
Dallal
Gerard E
GE
Keusch
Gerald T
GT
Singh
Maria Fiatarone
MF
Hamer
Davidson H
DH
D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000008:administration & dosage*; D003139:Common Cold / Q000453:epidemiology / Q000517:prevention & control; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006707:Homes for the Aged; D006801:Humans; D008297:Male; D009735:Nursing Homes; D009752:Nutritional Status; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000517:prevention & control; D014810:Vitamin E / Q000008:administration & dosage*
D000975:Antioxidants; D014810:Vitamin E