Health shocks and changes in life purpose: Understanding the link between purpose and longevity

Abstract

SummaryBackgroundThe negative correlation between life purpose levels and subsequent morbidity and mortality is interpreted as evidence that a higher sense of life purpose causes healthier and longer lives. Causation, however, could run the other direction as a decline in health is, by definition, associated with greater morbidity and mortality risk and may also cause a decline in life purpose. We examine the relation between objective measures of changes in health and changes in purpose to better understand the causal mechanisms linking purpose to health and mortality.MethodsProspective cohort sample of 12 745 individuals aged 50 and older who were eligible to participate in the 2006, 2010, or 2014 Health and Retirement Study Psychosocial and Lifestyle questionnaire. The final sample consists of 15 034 observations measured over three four-year periods from 5 147 individuals. Controlling for standard covariates, we examined the relation between changes in purpose and 14 contemporaneous and subsequent objectively measured changes in health—lung function, grip strength, walking speed, balance, and physician diagnoses of hypertension, diabetes, cancer, lung disease, heart condition, stroke, psychiatric problem, arthritis, dementia, and Alzheimer’s disease.FindingsThere is strong evidence that negative health shocks cause a decline in life purpose as individuals who suffer a negative health shock experience a statistically meaningful contemporaneous decline in life purpose for 12 of the 14 changes in health metrics. In contrast, there is relatively weak evidence that a decline in purpose contributes to a deterioration of future health.InterpretationMuch of the relation between life purpose levels and mortality risk arises from reverse causation—a decline in health causes both increased mortality risk and lower life purpose. There is little evidence that life purpose interventions would alter future morbidity or mortality.FundingNone.Research in contextEvidence before this studyWe searched PubMed and Google Scholar with no language or date restriction for the term “life purpose” and found four comprehensive reviews of the life purpose or psychological well-being (which included life purpose in the set of psychological well-being metrics) literatures in the last three years and a 2016 meta-analysis of the relation between life purpose and mortality. Although acknowledging the possibility that reverse causation plays a role in linking life purpose levels to subsequent morbidity and mortality, the prevalent view appears to be that even when controlling for current health levels, higher life purpose causes behavioral, biological, or stress buffering changes that, in turn, cause lower future morbidity and mortality.Added value of this studyBy focusing on changes in health, changes in life purpose, and a longer horizon, we find strong evidence that changes in health cause changes in life purpose, but, contrary to the conclusions of most previous work, there is little evidence changes in life purpose cause changes in behavior, biology, or stress-buffering that, in turn, cause changes in future health.Implications of all the available evidenceAlthough life purpose intervention—either at the provider level or in public policy—may have benefits, there is little evidence to suggest it will cause greater longevity or lower future illness.