Association of blood pressure levels in the nonhypertensive range with mortality among people without traditional risk factors

Background: While emerging evidence suggests guideline-defined nonhypertensive blood pressure (BP) may encompass heterogeneous risk, the relationship between BP variations within nonhypertensive ranges and mortality risk remains inadequately characterized among individuals without traditional cardiovascular risk factors. This study investigated whether nonhypertensive range of SBP, DBP, and pulse pressure (PP) are associated with long-term mortality in a healthy population. Methods: This study included 80 730 UK Biobank participants without traditional cardiovascular risk factors and with nonhypertensive BP (SBP <140 mmHg, DBP <90 mmHg, and PP <60 mmHg). Participants were followed up for all-cause, cardiovascular, and noncardiovascular mortality. Associations were assessed using multivariable Cox proportional hazards models with restricted cubic splines. Results: Over a median follow-up of 13.7 years, 2553 deaths occurred. SBP and PP showed significant nonlinear associations with all-cause mortality ( P -overall <0.01), while DBP showed a linear inverse association ( P -overall = 0.049). Compared to the third quintile, the lowest PP quintile (<40 mmHg) was associated with 26% higher mortality risk (hazard ratio 1.26, 95% confidence interval [95% CI] 1.10–1.44), and the highest quintile (53–60 mmHg) with 14% higher risk (hazard ratio 1.14, 95% CI 1.01–1.28). The lowest SBP quintile (<114 mmHg) was associated with 16% higher risk (hazard ratio 1.16, 95% CI 1.02–1.32) compared to the third quintile (120–126 mmHg). Conclusion: Even within nonhypertensive ranges, the lowest and highest quintiles of PP level, as well as low-normal SBP and DBP levels, were associated with increased mortality risk in a healthy population.