Systolic blood pressure and cardiovascular mortality in middle-aged and elderly adults - The Singapore Chinese Health Study

Background: While elevated systolic blood pressure (SBP) is related to cardiovascular disease (CVD) mortality, it is unclear if the optimal SBP level may differ by age or the presence of underlying CVD. Objective: We investigated the association between SBP categories and CVD mortality among middle-aged and elderly adults with and without CVD history. Methods: We used data from 30,692 participants of the population-based Singapore Chinese Health Study who had blood pressures measured using a standard protocol at ages 48-85 years between 1994 and 2005. Information on lifestyle factors were collected at recruitment (1993-1998) and during follow-up interviews (1999 and 2004). Mortality was identified via nationwide registry linkage up to 31 December 2014. Results: SBP 120-139 mm Hg category was associated with lowest risk of CVD mortality in both age-groups of <60 and 60+ years, as well as in those with and without underlying coronary heart disease or stroke. Overall, compared to this category, CVD risk was non-significantly increased in lower SBP categories and significantly increased in the higher SBP categories. The risk estimates associated with elevated SBP were higher among those <60 years compared to their older counterparts, but less distinct between those with and without underlying CVD. Conclusion: SBP 120-139 mm Hg was associated with the lowest risk of CVD mortality in middle aged and elderly adults, regardless of underlying CVD. Although risks in both adult groups were similar, there is a greater risk associated with higher SBP among those aged below 60 years, highlighting a greater urgency of treatment in this younger group. (C) 2016 Elsevier Ireland Ltd. All rights reserved.