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.