PS-BPP05-1: ASSOCIATIONS OF ENVIRONMENTAL TEMPERATURES AND HOME BLOOD PRESSURE: THE MASUDA STUDY

Abstract

Objective: The prevalence of elevated blood pressure (BP) remains high, with the greatest absolute burden of elevated BP particularly in the East Asian and Pacific regions. Temperature and BP are closely related; however, few studies have examined the association of out-of-office BP with indoor or outdoor temperature. The effect of the difference between indoor and outdoor temperatures on BP also remains unknown. we examined the association of indoor and outdoor temperatures, and their difference with self-measured BP at home. Design and method: Using 2-year data on temperature and self-measured home BP in healthy 352 participants (mean age, 49.8 years; 46.0% women) from a population-based cohort. We measured home BP and indoor temperature at the same time in the morning and evening every day. Outdoor temperature at the same time period of the home BP measurements in Masuda City was based on the national data from the Japan Meteorological Agency. A linear mixed model was used for analyzing the association between home BP and indoor or outdoor temperature as fixed effects and each participant as a random effect adjusted for age, sex, smoking status, alcohol drinking, obesity, physical activity, diabetes mellitus, and antihypertensive medication use. Results: We observed BP measurements of 82,900 in the morning and of 66,420 in the evening. After adjustment for age, sex, and possible confounders, indoor temperature was inversely associated with systolic and diastolic BP in the morning and evening. A 1 °C increase in the indoor temperature reduced systolic/diastolic BP by 0.37/0.22 mmHg, respectively, in the morning and 0.45/0.30 mmHg, respectively, in the evening (all P-values < 0.001). The magnitude of associations was stronger for indoor than outdoor temperature. Similarly, a 1 °C increase in the indoor temperature above outdoor temperature decreased systolic/diastolic BP by 0.33/0.12 mmHg, respectively, in the morning and 0.45/0.26 mmHg, respectively, in the evening independent of outdoor temperature (all P-values < 0.001). Conclusions: Our findings highlight the importance of indoor temperature for influencing home BP levels. The control of indoor temperature is considered an easy approach for the general population to tackle. It is necessary to control the rise in home BP by controlling indoor temperature in order to reduce high BP, possibly leading to reduced mortality and morbidity from CVD.