Enjoying life could be the key to living longer, according to new research.
A study by University College London (UCL) has found those who enjoy life the most are three times more likely to live longer than those who don't.
The research also suggested future disability and poor health could be predicted by the state of a person's mind, and that happiness could be used as an indicator to spot people at risk of ill health.
According to the research team, including researchers from UCL, NatCen Social Research, the University of Manchester, and the Institute for Fiscal Studies, the effects were independent of age, sex and wealth.
The study tracked the psychological well-being of 10,000 people between the ages of 50 to 100 over nine years as part of the university's English Longitudinal Study of Ageing.
Participants were interviewed three times between 2002 and 2011 and their enjoyment of life assessed with a series of questions and psychological tests.
Those thought to have the greatest enjoyment of life at the first interview stage were more likely to remain alive nine or 10 years later.
Possible reasons why happier people live longer
'The difference between those who enjoyed life the most and those who enjoyed life the least was marked, with nearly three times more people dying in the lower than greater enjoyment group,' the study said.
According to Professor Andrew Steptoe, who led part of the research, one of the possible explanations for the findings is that happier people are less stressed and more likely to take care of themselves.
He also suggested that environmental factors, such as strong social networks, could be at play.
'What we have found is over a nine year period that about 20% of people will pass away during this time,' he said.
'What we found is that out of those people in the highest third of people with the most enjoyment, 9.9% died. Of people in the lowest third of enjoyment 28.8% of them died.
'This was the case even when factors such as age were taken into account, we still find this protective effect of enjoyment.'
The report also found one in six people over the age of 50 in England to be socially isolated. The less wealthy over-50s were twice as likely to be socially isolated than their wealthier counterparts.
Copyright Press Association 2012