County-level association between modifiable health behaviors and premature mortality in the United States.

Objective: Unhealthy lifestyle habits are associated with increased morbidity and mortality. This study aims to examine the county-level association of physical inactivity, insufficient sleep, and current smoking, three elements of the American Heart Association's Life's Essential 8, with premature mortality.

Methods: Premature country-level age-adjusted death rate (AADR) in 2018-2020 were obtained from National Center for Health Statistics Mortality Files. County-level data were included from County Health Rankings data set for 2022. Counties were divided into deciles based on the percentage of adults with physical inactivity, insufficient sleep, and current smoking (separate decile for each metric) from Behavioral Risk Factor Surveillance System in 2019. Multivariable linear regression were used to evaluate the association of premature AADR with physical inactivity, insufficient sleep, and current smoking (lowest deciles as reference), controlling for median county income as a social determinant of health.

Results: A total of 3082 counties were included in the analysis. Mean physical inactivity, current smoking, and insufficient sleep ranged from 20.7 % to 41 %, 13.4 % to 28.2 %, and 30.3 % to 43.7 % from 1st to 10th decile, respectively. There was a stepwise increase in premature mortality in each progressive decile with an increase in county-level physical inactivity, insufficient sleep, and current smoking, which remained significant in the adjusted analyses.

Conclusion: We demonstrate an independent association of county-level physical inactivity, insufficient sleep, and current smoking with premature mortality. Further research and public health efforts are needed to understand and mitigate these risk factors at the county level to improve health outcomes.