Age-specific associations between systolic blood pressure and cardiovascular mortality

Objective We aimed to identify the following in all age groups among individuals without known hypertension and CVD: (1) Whether a systolic blood pressure (SBP) of 130-139 mm Hg elevates cardiovascular disease (CVD) mortality. (2) Whether SBP shows a linear association with cause-specific CVD mortality. Methods We used the Korean National Health Insurance sample data (n=429 220). Participants were categorised into three groups by age (40-59 years, 60-69 years and 70-80 years). Results During 10.4 years of follow-up, 4319 cardiovascular deaths occurred. A positive and graded association was generally observed between SBP and overall and cause-specific CVD mortality regardless of age, except for ischaemic heart disease (IHD) mortality in those aged 70-80 years. Among those aged 70-80 years, the HRs (95% CIs) for overall CVD mortality were 1.08 (0.92-1.28), 1.14 (0.97-1.34) and 1.34 (1.14-1.58) for SBP values of 120-129 mm Hg, 130-139 mm Hg and 140-149 mm Hg, respectively, compared with SBP < 120 mm Hg. For total stroke mortality, the corresponding HRs were 1.29 (1.02-1.64), 1.37 (1.09-1.72) and 1.52 (1.20-1.93), while for IHD mortality, the corresponding HRs were 0.90 (0.64-1.26), 0.86 (0.62-1.19) and 1.29 (0.93-1.78), respectively. Non-linear associations were significant for IHD. Conclusions In the elderly Korean population, SBPs of 130-139 mm Hg elevated total stroke mortality, but not IHD mortality, compared with normal blood pressure, and a linear association was not observed for IHD mortality in the range < 140 mm Hg.