Greater levels of psychological well-being are associated with reduced disease and
mortality risk, and lifestyle habits may be potential mechanisms underlying these
relationships. Prospective studies show that positive psychological factors enhance
the likelihood of adopting specific health behaviors; yet, whether they promote the
adoption of multiple healthy behaviors, which can have a multiplicative effect on
disease and mortality risk compared to individual behaviors, is unknown. We investigated
whether happiness and optimism were related to a healthy lifestyle (characterized
by multiple health behaviors) over 10-22 years of follow-up; we also explored bidirectional
associations, assessing if a healthy lifestyle at baseline was related to greater
likelihood of experiencing higher happiness and optimism over time. Women reported
levels of happiness in 1992 (N=52,133) and optimism in 2004 (N=36,802). Health-related
behaviors (physical activity, body mass index, diet, alcohol and tobacco consumption)
were self-reported and combined into a lifestyle score, every four years from baseline
until 2014. Multivariable generalized estimating equations with a Poisson distribution
were used. Women with moderate and higher (versus lower) happiness levels were more
likely to report sustaining healthy lifestyles (RR=1.18, CI= 1.11-1.25; RR=1.39, CI=1.32-1.46,
respectively). In secondary analyses, the magnitude of the inverse association was
somewhat smaller (likelihood of sustaining higher happiness levels for baseline healthy
versus unhealthy lifestyle, RR=1.11, CI=1.10-1.12). Results were similar when considering
optimism as the exposure and in other secondary analyses (e.g., across individual
habits). While bidirectional associations are apparent, these findings suggest pursuing
happiness and optimism as modifiable determinants of lifestyle deserves further consideration.