Lowering midlife levels of systolic blood pressure as a public health strategy to reduce late-life dementia: perspective from the Honolulu Heart Program/Honolulu Asia Aging Study.

To estimate the potential benefits of lowering systolic blood pressure (SBP) toward preventing late-life dementia, we estimated the population-attributable risk of elevated SBP for dementia. Analyses are based on the cohort of 8006 Japanese American men (born 1900-1919) followed since 1965 as a part of the Honolulu Heart Program, continued as the Honolulu Asia Aging Study. Midlife cardiovascular risk factors and late-life brain function are well described. We estimated the population-attributable risk of dementia cases attributed to midlife SBP, grouped by the seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure criteria (<120, 120 to <140, and > or =140 mm Hg), taking into account treatment history, confounding factors, and competitive risk for death. The analysis is based on 7878 subjects, including 491 cases of dementia, with a mean interval of 25 years between measurement of blood pressure and dementia diagnosis. Compared with those with SBP <120 mm Hg, untreated, and <50 years of age at baseline, 17.7% (95% CI: 4.6% to 29.1%) of the cases were attributable to prehypertensive levels (SBP: 120 to <140 mm Hg) of SBP, translating into 11 excess cases per 1000. Among those who did not report taking antihypertensive medication in midlife, 27% (95% CI: 8.9% to 42.1%) of dementia cases can be attributed to systolic BP > or =120 mm Hg, translating into 17 excess cases per 1000. Although population-attributable risk estimates for population subgroups may differ by relative risk for dementia or prevalence of elevated levels of blood pressure, these data suggest that reducing midlife systolic BP is an effective prevention strategy to reduce risk for late-life dementia.