Despite the popular belief, happiness does not reduce the risk of dying early, a new statistical study established. Or at least it does not in British middle-age women.
While it is true that unhappy people tend to have a shorter life, being ill in the first place makes people unhappy, the study published online this week found.
"Illness makes you unhappy, but unhappiness itself doesn't make you ill," study researcher Bette Liu, of the University of New South Wales in Australia, said in a statement. "We found no direct effect of unhappiness or stress on mortality."
The study is based on data from over 700,000 women in the UK collected under the Million Women Study. Participants in the survey, recruited between 1996 and 2001, filled in electronic questionnaires detailing their health, lifestyle and wellbeing. The surveys were conducted regularly for up to a decade.
The team at the UNSW looked for correlations between reported happiness and deaths and found that women who were unhappy were 29 percent more likely to die over the 10-year period, compared with the women who were happy most of the time.
However, when poor health and lifestyle factors such as smoking, obesity and physical inactivity were taken into account, no link between happiness and length of life was found. The researchers concluded that happiness or unhappiness themselves did not affect death rates.
"Many still believe that stress or unhappiness can directly cause disease, but they are simply confusing cause and effect," said Richard Peto, a co-author of the study and a professor of medical statistics and epidemiology at the University of Oxford in the United Kingdom.
Happiness is a subjective category and the study used a large but quite specific database. More research is required to establish whether the conclusion applies to men, who may experience happiness differently from women, as well as people of other age categories and cultures.