UK Study Finds No Association Between Self-Reported Unhappiness and Mortality Risk
As reported in The Lancet by Liu et al, a study in UK women that attempted to adjust for the effect of health and lifestyle factors found that self-reported unhappiness was not associated with an increased risk of mortality from cancer or other conditions.
Study Details
The study involved data from the UK Million Women Study, which recruited women between 1996 and 2001 and followed them for cause-specific mortality. At 3 years after recruitment, women completed a baseline questionnaire rating health, happiness, stress, feelings of control, and feeling of relaxation. Potential associations of these factors with mortality before January 2012 from all causes, ischemic heart disease, and cancer were examined among women who did not have heart disease, stroke, chronic obstructive lung disease, or cancer at the time of the baseline questionnaire.
Associations With Unhappiness, Mortality
Of 719,671 women included in the analysis (median age = 59 years), 39% reported being happy most of the time, 44% reported being usually happy, and 17% reported being unhappy. During 10 years of follow-up, 31,531 participants died (4%).
In analysis adjusted only for age, unhappiness was significantly associated with increased mortality (rate ratio [RR] = 1.29, 95% confidence interval [CI] = 1.25–1.33). The excess risk was partly accounted for by associations with personal characteristics, with self-rated health being the most important; poor health at baseline was strongly associated with unhappiness at baseline (odds ratio for happiness = 0.298, 95% CI = 0.293–0.303, for poor/fair vs excellent/good health).
After adjustment for self-rated health, unhappiness was no longer significantly associated with all-cause mortality (RR = 1.02, 95% CI = 0.98–1.05). After simultaneous adjustment for sociodemographic and lifestyle factors (age, region, deprivation level, education, body mass index, exercise, smoking, alcohol use, living with a partner/parity, group activities, daily sleep duration) and indices of health (self-rated health, treatment for hypertension, diabetes, asthma, arthritis, depression, or anxiety), the association between unhappiness and mortality was no longer apparent for all-cause mortality (fully adjusted RR = 0.98, 95% CI = 0.94–1.01), ischemic heart disease mortality (RR = 0.97, 95% CI = 0.87–1.10), or cancer mortality (RR = 0.98, 95% CI = 0.93–1.02). Similar findings were made using such measures as stress or lack of control.
The investigators concluded: “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 study was funded by the UK Medical Research Council, Cancer Research UK.
Bette Liu, DPhil, of the University of New South Wales, Australia, is the corresponding author The Lancet article.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
