Objective: To clarify whether the impact of normal and high-normal BP (BP) per se on cardiovascular disease (CVD) and all-cause death differs depending on smoking status.
Methods and results: A prospective observational cohort study (median follow-up period: 7.5 years) was performed among 25 077 healthy nondiabetic Japanese men aged 20–61 years (mean age 37.3 years), whose BP was less than 150/95 mmHg and who were not on medication. Hazard ratios (HRs), adjusted by known risk factors and a change in annual BP during the follow-up, were calculated by the Cox proportional model with less than 119/75 mmHg as a reference. Among smokers, CVD events increased significantly from a SBP of 120 mmHg, with HRs of 2.68 (120–129 mmHg), 4.28 (130–139 mmHg), and 11.7 (140–149 mmHg). The CVD events also increased from a DBP of 75 mmHg (P for trend less than 0.0001), with 75–79 mmHg and 90–94 mmHg considered statistically significant. Among noncurrent smokers, 110–149 mmHg (SBP) and 75–89 mmHg (DBP) were not associated with elevated HRs for CVD. The relation between BP and all-cause mortality was similar among both current and noncurrent smokers: 140–149 mmHg (SBP) and 90–94 mmHg (DBP) were significantly associated with elevated risk, and 130–139 mmHg (SBP) among noncurrent smokers associated with elevated risk.
Conclusion: Young and middle-aged healthy Japanese individuals with normal and high-normal BP (120–139/75–89 mmHg) were at risk for CVD among smokers, even after adjusting for an annual change in BP.