The influence of daily air temperature variability on arterial blood pressure: Findings from a Kaunas cohort study

Purpose Several studies reported statistically significant associations of blood pressure (BP) with short-term air temperature variability (TV), but the effect of TV on BP was found to differ in different areas. This study aimed to detect the association between BP and TV in Kaunas, Lithuania. Methods Data of the international HAPIEE (Health, Alcohol, and Psychosocial Factors in Eastern Europe) study was used to gather information on the participants' BP during 2006–2008. The TV variables were the diurnal temperature range and the standard deviation (SD) of hourly temperature during the 24 hours (TSD) and during the first 12 hours of the day (TSDF) as well as the SD of daily minimum and maximum temperatures during the exposure days (DTV). A multiple linear regression was used after controlling for potential confounders. Results Among the participants, 45.5% were men, 30.9% were aged > 65 years, and 9.8% were normotensive. A positive association of systolic BP with all TV variables and of diastolic BP with TSD and TSDF was found, a stronger impact being observed in males and physically active participants. The impact of TV was stronger during lower temperatures, and a statistically significant negative interaction term between air temperature and TV variables was found. In May-June, a negative association of DTV with diastolic BP was observed, a stronger effect being found in hypertensive and physically active participants. Conclusions We found a positive association of BP with TV. Sex, the level of physical activity, and air temperature may modify the relationship between TV and BP.