Introduction: Cross-sectional and longitudinal studies revealed association between low ambient temperature and increased office blood pressure, but few studies evaluated the effect of short-term exposure to cold temperature on home blood pressure (HBP).
Objective: We aimed to investigate the relationship between short-term ambient temperature exposure and HBP.
Methods: A total of 367 patients who had joined a telehealth program in a university-affiliated hospital from 2009 to 2013 were enrolled in this retrospective study. Blood pressure was measured repeatedly at home during the study period and data were automatically transmitted to the server of the hospital for storage. Demographic and clinical details were collected. Hourly meteorological data during the same time period were obtained from government weather bureau. Marginal regression models using the generalized estimating equations (GEE) method were used for statistical analysis.
Results: A total of 118,801 HBP measurements were collected from 367 patients during the study period. All HBP parameters (including mean, systolic and diastolic BP) were significantly affected by ambient temperature parameters (including the temperature while HBP measured, the temperature difference within the past 12 hours and the maximum temperature in the past 24 hours). Demographic factors were also significantly associated with HBP (table). After adjusting for age, gender and comorbidities, a 1-Celcius-degree decrease in ambient temperature was associated with increases of 0.255 mmHg in SBP and 0.037 mmHg in DBP. A 1-Celcius-degree temperature difference within the past 12 hours was associated with rises of 0.181 and 0.149 mmHg in SBP and DBP, respectively.
Conclusions: Short-term exposure to cold ambient temperature and large temperature difference was associated with higher HBP.