Association between systolic/diastolic blood pressure and the incidence of cognitive impairment
The results were based on additive Cox-regression model taking SBP/DBP as a smoothing term. The models have adjusted for age, sex, education, co-residence, and residence, smoking, drinking, frequent vegetable consumption, frequent fruit consumption, frequent physical activity, impaired activity of daily living, obesity, activities of daily living, self-reported diabetes mellitus, self-reported heart disease, and self-reported cerebrovascular disease.
The histograms at the bottom of each panel present the distribution of SBP/DBP of included participants. For the estimated hazard ratio for SBP (Panel A & B), the hazards at inflection point with the lowest hazard (Panel A: SBP = 110 mmHg, Panel B: SBP = 120 mmHg) were considered as the reference. Because no inflection points for DBP (Panel C & D) were identified, the hazards at DBP 80 mmHg, the definition of normal blood pressure for Chinse adults, were considered as the reference.
MMSE: mini-mental state examination; SBP: systolic blood pressure; DBP: diastolic blood pressure.