Abstract
Background Understanding the natural history of elevated blood pressure (BP) is important to determine the window for primary prevention of hypertension. The authors aimed to investigate the natural history of elevated BP and examine whether there were inflection points in BP trajectories preceding hypertension onset in Chinese adults. Methods and Results A total of 8688 participants with an average of 5 BP measurements were included from the CHNS (China Health and Nutrition Survey). In each wave, triplicate measurements on the same arm were taken, and the mean systolic BP (SBP) and diastolic BP (DBP) were used in the analysis. Hypertension onset was defined as SBP ≥140 mm Hg or DBP ≥90 mm Hg or diagnosed by physician or currently under antihypertensive treatment. The median follow-up time was 13.0 years. Overall, BP elevation with age prior to the onset of hypertension showed a nonlinear trajectory. The increased rates in both SBP and DBP were obviously faster after the inflection point than before. According to hypertension onset at age 30 to 39, 40 to 49, 50 to 59, 60 to 69, and 70 to 79 years, at the inflection point, patients were ≈29, 38, 48, 57, and 67 years, SBP levels were 112.6, 114.8, 116.8, 117.4, and 118.0 mm Hg, and DBP levels were 73.4, 75.7, 76.9, 76.2, and 73.8 mm Hg, respectively. Conclusions There was a nonlinear trajectory of BP elevation preceding hypertension onset. The inflection points for SBP and DBP were in the range of 112 to 118 mm Hg and 73 to 77 mm Hg, respectively. Once BP levels exceeded the changing points, the level of SBP and DBP increased more rapidly.