The where of when: Geographic variation in the timing of recent increases in US county-level heart disease death rates.

Purpose: Within the context of local increases in US heart disease death rates, we estimated when increasing heart disease death rates began by county among adults aged 35-64 years and characterized geographic variation.

Methods: We applied Bayesian spatiotemporal models to vital statistics data to estimate the timing (i.e., the year) of increasing county-level heart disease death rates during 1999-2019 among adults aged 35-64 years. To examine geographic variation, we stratified results by US Census region and urban-rural classification.

Results: The onset of increasing heart disease death rates among adults aged 35-64 years spanned the two-decade study period from 1999 to 2019. Overall, 43.5% (95% CI: 41.3, 45.6) of counties began increasing before 2011, with early increases more prevalent outside of the most urban counties and outside of the Northeast. Roughly one-in-five (18.4% [95% CI: 15.6, 20.7]) counties continued to decline throughout the study period.

Conclusions: This variation suggests that factors associated with these geographic classifications may be critical in establishing the timing of changing trends in heart disease death rates. These results reinforce the importance of spatiotemporal surveillance in the early identification of adverse trends and in informing opportunities for tailored policies and programs.