Descriptive epidemiology of blood pressure response to change in body position - The ARIC study

The epidemiology of a common measure of cardiovascular reactivity, the chan ge in systolic blood pressure (Delta SBP) from the supine to the standing p osition, is described in a cohort of 13 340 men and women aged 45 to 65 yea rs enrolled in the Atherosclerosis Risk in Communities (ARIC) Study. The di stribution of Delta SBP was found to be symmetrical and unimodal, with a me an value near zero (-0.45 mm Hg), The range of Delta SBP was from -63.2 to 54.3 mm Hg, and the standard deviation was 10.8. Stratification of Delta SB P by race and gender shows a slight shift in distribution toward higher val ues for black men and women. Delta SBP was categorized into deciles. Partic ipants in the top 30% and bottom 30% of the distribution were compared with individuals in the middle 40% of the distribution, who had little or no ch ange in SEP on standing. Participants in the bottom 30% (ie, SEP decreased on standing) were significantly older, had a greater prevalence of hyperten sion and peripheral vascular disease, had higher values of SEP, and had mor e cigarette-years of smoking. Among participants in the top 30% (ie, SEP in creased on standing), a significantly larger proportion were black, mean se ated SEP was higher, and the predicted risk of developing coronary heart di sease after 8 years was greater. The response of SEP to change in posture s howed considerable variability in a population sample of middle-aged adults . Cardiovascular morbidity, sociodemographic factors, and cigarette smoking were associated with the magnitude and direction of the postural change.