The new research – featured in the Christmas issue of The BMJ – builds on a previous study by the team that looked at subjective well-being (feelings of enjoyment and satisfaction with life) on a single occasion.
Their earlier findings were promising and showed that enjoyment of life during a single moment in time was associated with a longer life. However, the team planned to take the research one step further and conduct a new study that analyzed whether enjoyment of life over a longer period would show the same results.
The University College London (UCL) researchers put forward the question: how important is sustained well-being? They aimed to examine whether enjoyment of life reported time after time over several years would have a stronger correlation with mortality than enjoyment of life reported as a single occurrence.
The study included 9,365 adults with an average age of 63 years. The participants were taking part in the English Longitudinal Study of Ageing (ELSA), which is a study of men and women age 50 and older living in England.
Almost one quarter of people experienced no life enjoyment
Enjoyment of life was assessed three times at 2-year intervals between 2002-2006 through questionnaires, and associations with mortality were evaluated up to 2013.
The participants were asked to rate the following statements on a four-point scale to measure life enjoyment: “I enjoy the things that I do;” “I enjoy being in the company of others;” “On balance, I look back on my life with a sense of happiness;” “I feel full of energy these days.”
People in the group who responded with “never or rarely” to each of the four statements were classified as having no enjoyment. Individuals who responded with “sometimes or often” to each of the four statements were categorized as having high enjoyment.
No high levels of life enjoyment on any occasion were seen in 2,264 (24 percent) of participants. A total of 1,833 (20 percent) participants had one, 2,063 (22 percent) had two, and 3,205 (34 percent) had three instances of high enjoyment.
During the follow-up period, there were 1,310 deaths. The death rate was progressively higher among individuals who reported fewer occasions of high enjoyment.
The investigators took a range of factors into account that could influence the results of the study, such as education, depressed mood, underlying health issues, and wealth.
Higher rates of life enjoyment associated with lower risk of death
Compared with the group that reported no enjoyment, the risk of death from all causes was 17 percent lower among participants who reported two instances of high enjoyment and 24 percent lower in those reporting three instances of high enjoyment of life.
Reports of high life enjoyment occurrences were greater in women, as well as in participants who were married or cohabiting, currently employed, well-educated, wealthier, and younger.
The study results confirmed the UCL team’s hypothesis; the longer an individual reports enjoying life, the lower their risk of death. The authors write:
“These results add a new dimension to understanding the significance of subjective well-being for physical health outcomes by documenting a dose-response association with sustained well-being. This complements previous findings on well-being intensity, and demonstrating significant effects after controlling for a wide range of potential confounders.”
In the study, the authors discuss that reverse cause-and-effect may bias the results. They say that, for a person with a serious illness, there can be a knock-on effect of a lack of enjoyment in life and, as a result, may increase the risk of death.
To avoid this bias, the researchers restricted deaths included in the analysis to at least 2 years after the last measurement point. However, limiting the data in this way made no difference to the overall findings.
“The findings highlight the need to study biological and behavioral mediators in order to establish the mechanisms through which subjective well-being is associated with health outcomes,”