We investigated the association of systolic blood pressure (SBP) level with physical frailty and cognitive function in community-dwelling older Japanese. Using the 'Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians' survey as the baseline, we performed a cross-sectional analysis of people aged 70 ± 1 (n = 1000), 80 ± 1 (n = 978), and 90 ± 1 (n = 272) years. Medical histories and medications were collected via interviews conducted by medical professionals. Blood pressure (BP), grip strength, gait speed, and cognitive function were examined on site. Trend analysis and multiple regression analysis were used to determine the association of the SBP level with physical frailty and cognitive function. The principal finding was that the association of SBP with physical frailty and cognitive function varied depending on characteristics such as age, physical and cognitive function, and antihypertensive medication use. A lower SBP level was associated with a higher prevalence of physical frailty only among 80-year-olds who were on antihypertensive medication. A significant association was found between higher SBP and lower cognitive function among 70-year-olds, while among 90-year-olds, the opposite was found. No association was found among participants who were 80 years old or among participants of all ages without antihypertensive medication. Our finding that an inverted association between SBP and geriatric syndrome exists suggests that the treatment of older patients must be individualized to prevent geriatric syndrome.
Keywords: Blood pressure; Cognitive function; Community-dwelling older population; Hypertension; Physical frailty.