Many of us believe that being happy can make life longer. This may be because happiness makes the body stronger and healthier. On the other hand, unhappiness may cause illness and increase mortality.
However, a recent study shows that happiness does not directly affect mortality. The conclusion is drawn based on a longitude research on million UK women. The finding is published in The Lancet.
Researchers tested 1.3 million women aged 50-69 during 1996 – 2001. After recruitment, and every 3-5 years subsequently, these women answered a questionnaire about their happiness, stress, feelings of control, feelings of wellbeing, relaxation and lifestyle.
In addition, researchers followed the women’s death, cancer registration, and hospital admission until 2012. To analyze the relation between happiness and mortality, they controlled the influences of self-rated health and lifestyle factors (e.g., smoking, BMI, deprivation, etc.).
The result showed that among 719,671 women in the main analysis, 39% reported being happy all the time, 44% reported always happy, and 17% reported unhappy. During the 10-year follow-up after recruitment, 4% of women died.
Although unhappiness was strongly related to self-rated poor health, it was not associated with mortality ratio, no matter what caused the death. This effect was generated after controlling self-rated health, illness treatment, and lifestyle factors.
Researchers suggest that happiness seems to influence mortality, but this is because of many confounding factors. When these factors are controlled, happiness does not appear to have any direct effect on mortality.
Citation: Liu B, Floud S, Pirie K, Green J, Peto R, Beral V; Million Women Study Collaborators. (2016). Does happiness itself directly affect mortality? The prospective UK Million Women Study. The Lancet, 387: 874-881. doi: 10.1016/S0140-6736(15)01087-9
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