Declines in heart rate variability associated with short-term PM2.5 exposure were modified by blood pressure control and treatment: A multi-city panel study in China

Abstract Exposure to fine particulate matter (PM2.5) was associated with altered heart rate variability (HRV). However, whether blood pressure (BP) control and angiotensin II receptor blocker (ARB) treatment modifies the associations was seldom addressed. Therefore, we conducted a 3-phase panel study among 282 hypertensive subjects aged 35–74 years in four cities of China to address this issue. Real-time personal PM2.5 sampling and 24-h ambulatory electrocardiogram monitoring were performed repeatedly in 3 different seasons. Linear mixed-effects models were fitted overall and by control status of BP and ARB treatment to assess the associations between short-term PM2.5 exposure and HRV. The average hourly PM2.5 concentrations (Mean ± SD) ranged from 19.3 ± 18.2 μg/m3 to 99.4 ± 76.9 μg/m3 across study phases and cities. Generally, PM2.5 exposure was associated with decreased hourly and 24-h HRV. However, these adverse impacts were attenuated among patients with controlled BP (