Temperature-adjusted hypertension prevalence and control rate: a series of cross-sectional studies in Guangdong Province, China

Background Previous studies have shown negative relationships between ambient temperature and blood pressure (BP). However, few studies estimated temperature-adjusted hypertension prevalence and control rate in different population. Objective To estimate the effects of temperature on BP, and further calculate temperature-adjusted hypertension prevalence and control rate. Methods Meteorological and BP data in Guangdong Province from 2004 to 2015 were collected. There were 31 351 participants aged 18 years and over. Based on 2018 European society Arterial Hypertension Guidelines, participants were divided into normotensive patients (n = 23 046), known hypertensive patients (n = 2807), and newly detected hypertensive patients (n = 5498). We first used generalized additive model to establish the nonlinear relationship between daily mean temperature and BP, and then calculated the linear effects of temperature on BP among populations with different hypertension status. Finally, we calculated the temperature-adjusted hypertension prevalence and control rate. Results Generally, there is an inverse relationship between temperature and BP. For a 1 °C increase in temperature, the decreased SBPs for normotensive patients, newly detected hypertensive patients, and known hypertensive patients were 0.37 [95% confidence interval (CI): -0.40, -0.33] mmHg, 0.21 (95% CI: -0.32, -0.10) mmHg and 0.81 (95% CI: -1.02, -0.59) mmHg, while reduced DBPs were 0.19 (95% CI: -0.21, -0.16) mmHg, 0.01 (95% CI: -0.06,0.08) mmHg, and 0.44 (95% CI: -0.56, -0.32) mmHg, respectively. At 5, 10, 15, 20, and 25 °C, the hypertension prevalence rates were 32.5, 29.7, 27.7, 26.0, and 25.0%, respectively, and the control rates were 12.0, 17.5, 23.5, 30.1, and 37.1%, respectively. Conclusion Low temperature increased BP for all populations, especially for known hypertensive patients, which makes hypertension prevalence increase and control rate decrease if temperature reduce. Our findings suggest that temperature should be considered in hypertension clinic management and epidemiological survey.