Multivitamins lack evidence to support benefit for elderly, finds review
and mineral supplements prevent infections in elderly people,
according to a meta-analysis published on the BMJ website today.
The trials reviewed do not include research published in JAMA last year, which found nursing home residents supplemented with vitamin E were 20 per cent less likely to get a cold and also had less colds over the study period than a placebo group.
However in a search of medical journals up to January 2004, the UK researchers found only eight trials that met the inclusion criteria of being randomized, placebo controlled studies that evaluated a combination of multivitamins and mineral supplements in an elderly population. They also had to report an infection-related outcome.
Variability between these studies was considerable with respect to duration of follow-up, infections assessed and number of subjects, noted Alexander Sutton from the University of Leicester and Alia El-Kadiki from the Royal Hallamshire hospital in Sheffield.
Three trials reported mean difference of number of days spent with infections on multivitamins and minerals compared with placebo over 12 months. All three show a significant reduction in days of infection for the multivitamin and mineral group and the pooled estimate of a benefit of around 17.5 days, write the researchers.
However taking into account other outcomes, such as infection incidence in the vitamin groups, and reporting of adverse events, which was poor in all studies, the researchers concluded that overall the evidence was of poor to moderate quality and conflicting.
The findings are significant because the number of elderly people in developed nations is one of the fastest growing population segments. People over the age of 65 are set to make up a quarter of the total European population by 2020. The most dramatic demographic changes for the future will be in the oldest age group (80 years and over) that is estimated to grow from 21.4 million in 2000 to 35 million in 2025.
This population group is also more prone to infection and researchers have been increasingly looking at whether certain nutrients can lower this risk.
The authors add however that "the results of this review are sufficiently encouraging to warrant further and more expansive studies in this area of considerable public health importance".
