Happy people do not necessarily live longer, as those with positive attitudes are more likely to take risks with their health, experts have found, making them more likely to find a care home.
Research at the University of California, Riverside, found that participants of the longitudinal study who were the most cheerful and had the best sense of humour during childhood tended to live shorter lives - challenging assumptions made by other scientists and the media.
Howard S Friedman, who led the 20-year study, explained that an 'everything will be fine' attitude can shorten lives.
"Prudence and persistence, however, led to a lot of important benefits for many years. It turns out that happiness is not a root cause of good health. Instead, happiness and health go together because they have common roots."
It was also found that marriages are good for men's health, but do not really make a difference to that of women. Additionally, being divorced is much less harmful to a woman's health than that of a man.
This comes after researchers from the Public Research Center for Health in Luxembourg found that older people who practise speaking other languages throughout their lifetime have a lesser chance of cognitive decline.