Percent change (95% CI) in Standard deviation of normal-to-normtal interval, low frequency and high frequency associated with a 10-µg/m3 increase in PM2.5 by LPL-N291S, LPL-S447S, LPL-D9N and VEGF-G634C gene polymorphisms, wild type vs non-wild types (wild^) adjusting for age, body mass index, mean arterial blood pressure, fasting blood glucose, cigarette smoking, alcohol consumption, season, room temperature and outdoor apparent temperature and uses of β-blockers, angiotension-converting enzyme inhibitors and calcium channel blockers.
*p<0.10, ** p<0.05 for interaction terms between PM2.5 and gene polymorphism (wild vs non-wild); SDNN: standard deviation of normal-to-normal intervals.