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.
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Contributors M-HJ and S-WY conceived and designed the study. S-WY acquired data and performed statistical analysis. M-HJ and S-WY wrote the first draft. M-HJ, S-WY, SJA, and J-JY analysed and interpreted data and contributed to critical revision of the manuscript. All authors have read and approved of the final submitted version of the manuscript. S-WY is the study guarantor.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Ethics approval This study was approved by the Institutional Review Board of Catholic Kwandong University, Republic of Korea.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The data are available from the NHIS of Korea (http://nhiss.nhis.or.kr/bd/ab/bdaba000eng.do). Applicants to use the data should contact the NHIS (Office of big data operation, +82-33-736-2469) for further information.
Patient consent for publication Not required.
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