Long-term ambient temperature and temperature variability in relation to incident hypertension among postmenopausal women

Objective Long-term ambient temperature and temperature variability may influence hypertension risk, yet epidemiologic evidence remains limited, particularly in large, geographically diverse cohorts. We therefore evaluated their associations with incident hypertension among postmenopausal women across the United States. Methods Analytical samples included 30,067 Women's Health Initiative Clinical Trial participants. Mean temperature and temperature variability were calculated as the mean and standard deviation of daily mean temperatures, respectively, during a participant-specific 5-year window ending at event or censoring. Incident medication-treated hypertension was defined as self-reported first initiation of antihypertensive medication through September 2010. Participants were grouped into nine geographic Results During a median follow-up of 12 years, 11,177 women (37.2%) developed hypertension. Mean temperature was not associated with incident hypertension; compared with Q1, the largest estimate was observed in Q4 (HR, 1.39; 95% CI, 0.73–2.64). For temperature variability, lower hazards were observed in Q4 (HR, 0.44; 95% CI, 0.24–0.82) and Q5 (HR, 0.40; 95% CI, 0.20–0.81) compared with Q1. However, the overall trend was not statistically significant (P-trend ​= ​0.066), and substantial geographic Conclusion Long-term mean temperature was not associated with incident medication-treated hypertension. The lower hazard estimates were observed in the highest temperature variability.