Happy women do not live any longer than sad women
Your life is a bed of roses and you are the happiest woman in town. But that does not mean that you will live any longer than the woman next door who is stressed and miserable.
Happiness does not guarantee a long life just as stress does not necessarily kill, report researchers who studied around a million women in the UK.
The study published in the Lancet medical journal found poor health can cause unhappiness but that does not appear to have any direct effect on mortality
"Previous reports of reduced mortality associated with happiness could be due to the increased mortality of people who are unhappy because of their poor health," the report says.
The happiness study
The Million Women Study is a 10-year-long study of UK women recruited between 1996 and 2001 and followed electronically for cause-specific mortality.
Three years after recruitment, the baseline questionnaire for the current report asked women to self-rate their health, happiness, stress, feelings of control and whether they felt relaxed.
The cause of death in the interim period was analysed for ischaemic heart disease, cancer among those who did not have heart disease, stroke and chronic obstructive lung disease.
Of 7,19,671 women studied, 39 percent reported being happy most of the time, 44 percent usually happy, and 17 percent unhappy.
During the 10 years of follow-up, more than 4 percent of the participants died. But the death rates among the unhappy were no higher than among those who said they were usually happy.
Unhappiness may make people behave in an unhealthy way, such as eating or drinking too much or harming themselves, suggest researchers.
"But if you ask does it of itself have any direct effect on mortality, it doesn't," Prof Sir Richard Peto of the University of Oxford told the Guardian.
"In middle-aged women, poor health can cause unhappiness. After allowing for this association and adjusting for potential confounders, happiness and related measures of well-being do not appear to have any direct effect on mortality," the researchers point out.
Researchers accept there is no perfect way to measure happiness, but factors associated by the women in the study with happiness were similar to what was found in other research.
Women were more likely to feel happy if they were older, less deprived, physically active, did not smoke, had a partner, belonged to a religious group or participated in social activities and had adequate sleep - but not too much.