By Keith Mulvihill
NEW YORK (Reuters Health) – Older men who smoke do not reduce their risk of rhinovirus infection by taking common "cold fighting" vitamins, new study findings suggest.
"We found no protective association between dietary vitamin C or E or beta-carotene and the incidence of self-reported colds," Dr. Harri Hemila of the University of Helsinki in Finland and colleagues report in the January issue of the journal Epidemiology.
Nonetheless, the study did identify a small population of men–those over the age of 65–whose intake of vitamin E was associated with a slightly reduced risk of catching colds. The effect was strongest among men who lived in cities and smoked fewer than 15 cigarettes daily.
However, Dr. Hemila all but dismissed this finding during an interview with Reuters Health, noting that the group represented only about 1% of men in the study. The 28% reduction in colds found in the group is "rather small and seems to have no practical relevance," he said.
"Whether [the finding] is due to a statistical artifact generated by the subgroup analyses, or due to a real physiological effect–that is an open question," Dr. Hemila added.
The researchers evaluated data from a study of nearly 22,000 male smokers that investigated whether supplementing their diets with 50 mg of vitamin E and 20 mg of beta-carotene daily had any effect on whether they developed cancer.
The men, between 50 and 69 years old, were also asked about the number of colds they had during the study period.
Past studies have found some evidence that vitamin C can help guard against the common cold, and that vitamin E may strengthen the immune system in older people.
"Although vitamins C and E may affect susceptibility to respiratory infections in restricted groups of subjects under special circumstances, the results of the present analysis and the findings of several other studies indicate that such subpopulations are not large in the Western countries," Dr. Hemila and colleagues conclude.