Association of ambient temperature and blood pressure in the Jackson Heart Study

Extreme temperature events related to climate change may impact blood pressure (BP). African American populations are disproportionately affected by temperature extremes due to structural inequities. We examined the association between ambient outdoor temperature and BP among participants in JHS, a cohort of African American adults residing in the tri-county area of Jackson, Mississippi. Our primary hypothesis is that daily higher outdoor ambient temperatures would be associated with lower BP. We used a linear-mixed effects model to determine the relationship between temperature and systolic and diastolic blood pressure (SBP and DBP) at three visits (N = 5296). Participants had BP readings across three visits: Visit 1 (2000-2004), Visit 2 (2005-2008), Visit 3 (2009-2013). Cardiovascular disease (CVD), diabetes, BP medication, sex, age, and visit number were included as adjustment variables. For every 1-degree Celsius higher average temperature from the mean, SBP was 0.11 mm Hg lower (95% CI: -0.14, -0.07, p < 0.001) in adjusted models. Similarly, for every 1-degree Celsius higher average temperature from the mean, DBP was 0.06 mm Hg lower (95% CI: -0.08, -0.04) in adjusted models. The associations were weakly curvilinear (inverted U-shape) with significant quadratic terms. This relationship was not modified by markers of socioeconomic status. This is the first study in the Jackson Heart Study (JHS) to investigate the association between temperature and blood pressure. Further research is needed to explore this relationship in vulnerable populations living in areas prone to extreme temperatures.