Cognitively intact and happy life expectancy in the US.

OBJECTIVES: We examine the number of years to be lived with and without cognitive impairment and with high self-assessed quality of life (i.e., happiness) among a nationally representative sample of Americans age 65 years and older. Two key questions are addressed: Can people have a high quality of life despite being cognitively impaired? Which is longer: happy life expectancy or cognitively intact life expectancy?

METHOD: Data from nine waves of the Health and Retirement Study (1998-2014) were used to estimate transition probabilities into and out of cognitively intact/impaired-un/happy states, as well as to death. Recently extended Bayesian multistate life table methods were used to estimate age-specific cognitively intact and happy life expectancy net of sex, race/ethnicity, education, and birth cohort.

RESULTS: Happiness and cognitive impairment were shown to coexist in both the gross cross-tabulated data and in the life tables. Happy life expectancy is approximately 25 percent longer than cognitively intact life expectancy at age 65, and by age 85 happy life expectancy is roughly double cognitively intact life expectancy, on average.

DISCUSSION: Lack of cognitive impairment is not a necessary condition for happiness. In other words, people can have a high quality of life despite being cognitively impaired.