Population attributable fraction of all-cause mortality due to non-normal blood pressure: results from the 2013 to 2016 baseline survey of the TMM CommCohort Study

Antihypertensive therapy has reduced cardiovascular mortality; however, challenges remain, including residual risk in treated patients and the population burden associated with borderline hypertension. Previous Japanese estimates of the population attributable fraction (PAF) are derived from older cohorts and often lacked stratification by treatment status. We conducted a prospective study of 61,495 participants (women: 56.7%, aged 60.7 ± 11.0 years) from the Tohoku Medical Megabank Community-Based Cohort Study. Participants were classified into six blood pressure (BP) categories based on the JSH 2019 guidelines, and further stratified by hypertension treatment status, resulting in 12 groups. Using untreated individuals with normal BP as the reference, we calculated multivariable-adjusted hazard ratios (HR), 95% confidence intervals (CI), and PAF for the remaining groups using Cox proportional hazards model. During a median follow-up of 6.5 years, 1909 deaths were recorded. HRs increased with rising BP in both untreated and treated participants. The overall PAF for all-cause mortality due to non-normal BP was 9.45%, with a marked sex difference (12.25% in male and 5.16% in female). The highest PAF contributions were observed in the treated Grade I hypertension group (2.18%) and the untreated elevated BP group (1.28%). In this contemporary Japanese cohort, non-normal BP accounts for 9.45% of all-cause mortality, representing a substantial public health burden, particularly among men. The substantial PAF contributions from both treated patients and untreated individuals with elevated BP highlight the importance of effective BP management for both primary and secondary prevention.