Which blood pressure measurement, systolic or diastolic, better predicts future hypertension in normotensive young adults?

The impact of age-related differences in blood pressure (BP) components on new-onset hypertension is not known. A follow-up examination of 93 303 normotensive individuals (mean age 41.1 years) who underwent a health checkup in 2005 was conducted every year for 8 years. The primary end point was new-onset hypertension (systolic BP [SBP]/diastolic BP [DBP] ≥140/90 mm Hg and/or the initiation of antihypertensive medications with self-reported hypertension). During the mean 4.9 years of follow-up, 14 590 subjects developed hypertension. The impact of DBP on the risk of developing hypertension compared with optimal BP (SBP <120 mm Hg and DBP <80 mm Hg) was significantly greater than that of SBP in subjects younger than 50 years (hazard ratios, 17.5 for isolated diastolic high-normal vs 10.5 for isolated systolic high-normal [P<.001]; 8.0 for isolated diastolic normal vs 4.1 for isolated systolic normal [P<.001]). Among the subjects 50 years and older, the corresponding effects of DBP and SBP were similar. Regarding the risk of new-onset hypertension, high DBP is more important than SBP in younger adults (<50 years) with normal or high-normal BP.