NEW YORK (Reuters Health) - Smarter children may enjoy longer lives, the results of a new study suggest.

The study, which followed elderly adults deemed gifted by childhood IQ tests, found that the higher their early IQs were, the longer they lived -- up to a point, at least. The survival advantage began to plateau after a childhood IQ of 163, an intelligence level few people reach.

Dr. Laurie T. Martin and Laura D. Kubzansky of the Harvard School of Public Health report these findings in the American Journal of Epidemiology.

Though the reasons for the link between IQ and longevity are not clear, it does not appear to be merely a reflection of income and social position. As children, the participants were from affluent families and most were white. Yet childhood IQ was still a factor in their lifespan.