"Sense of purpose 'adds years to life'," BBC News reports, after a new study found that having a purpose in life is linked to living longer, regardless of your age or retirement status. But this weak study can only show an association at best.
The US study asked more than 6,000 people aged 20 to 70 whether they felt they had a strong sense of purpose in life. This was assessed using a scoring system of how strongly people felt about the following statements:
They were also asked about their social relationships with others.
Death rates were recorded for the next 14 years. The study found that people who died scored lower on purpose in life and positive relations with others.
The study only assessed purpose in life using three questions at one point in time. This type of study could therefore only show an association between purpose in life and mortality rate at best. It did not take most of the other likely factors into account, such as physical activity, diet, smoking, alcohol consumption or illness.
Though this study lacks the power to prove that having a purpose prolongs your life, common sense suggests that it is likely to enrich it.
The study was carried out by researchers from Carleton University, Canada and the University of Rochester Medical Centre, US, and was funded by the US National Institute of Mental Health and the National Institute on Aging.
It was published in the peer-reviewed medical journal Psychological Science.
In general the media reported the story accurately, but many failed to point out any of the study's limitations. In particular, the lack of information on the physical health status of the participants or cause of death should have been discussed.
This was a retrospective cohort study. It aimed to see if having a purpose in life increased life expectancy.
As it was a retrospective study, it is open to study bias. It can show an association, but it is not able to prove that people who reported a strong purpose in life lived longer, as other factors could be responsible for any gains seen.
The study used data from 6,163 people that had been collected as part of a US study called MIDUS, a longitudinal study of health and wellbeing.
Participants were between the ages of 20 and 75 at the beginning of the study in 1994-95.
They completed a self-administered written questionnaire at home and also had a phone questionnaire.
Purpose in life was measured by their response on a scale of one (strongly disagree) to seven (strongly agree) to three statements:
The researchers analysed the responses in relation to mortality by looking at data from the National Death Index in 2010.
Statistical analysis was performed to look at the relationship between purpose in life and risk of death. They also analysed other factors, such as age, sex, ethnicity, educational level, retirement status, positive relationship with others, and feeling happy and positive or sad and negative over the previous 30 days. They then adjusted the results to take age and retirement status into account.
Over the 14-year period, 569 people died. Those more likely to have died were older, retired, male and with lower educational levels.
People who died scored lower on purpose in life and positive relations with others, meaning that greater purpose in life predicted a lower mortality risk (hazard ratio [HR] 0.85; 95% confidence interval [CI] 0.78 to 0.93).
There was no difference between survivors and those who died in terms of whether they reported feeling positive or negative in the questionnaire.
Further statistical analysis found that a sense of purpose reduced the risk of death by relatively the same amount for younger, middle-aged and older adults. The results remained significant whether or not people were retired.
They concluded that, "This study underscores the potential for purpose to influence healthy aging across adulthood and points to the need for further investigation on why finding a purpose may add years to one's life."
They suggest that further research should look at whether "daily physical activity and goal achievement" are the mechanisms behind their findings.
This study found an association between people who felt they had a purposeful life and a reduced risk of death.
Although researchers tried to control for the person's state of wellbeing at the time of the questionnaire – whether the person was feeling happy and positive or sad and negative when they responded to the three questions about purpose in life – the questionnaires were only conducted once. It is likely that people's responses may fluctuate and change over time for numerous reasons.
Determining a person's sense of purpose in life from their response to three questions is a very crude measure. The interpretation of each question could be viewed in a different light.
In this study, agreeing with the question "I live life one day at a time and don't really think about the future" appears to indicate that the person lacks purpose in life. However, this could be viewed as a positive attitude for some people suffering from ill health.
A major limitation of this study is that it did not record whether people had any illnesses, or indeed their cause of death.
Further limitations include the lack of general lifestyle information, which could have confounded the results. This includes information about:
In conclusion, this weak study suggests that having a purpose in life may improve life expectancy, but either way it is unlikely to reduce it.
There have been anecdotal reports that upon retirement many people suddenly find that their life loses purpose as they no longer have a career to think about (though for some, this is a blessing).
If you are having problems coping with retirement and are feeling increasingly socially isolated, there is a wide range of organisations that can help.