Stroke risk of blood pressure indices determined by home blood pressure measurement: the Ohasama study.
The purpose of this prospective cohort study was to investigate associations between stroke and blood pressure (BP) indices (systolic BP [SBP], diastolic BP [DBP], mean BP, and pulse pressure [PP]) determined by home BP measurement. Associations between stroke and BP indices were examined in a rural Japanese population. Home BP data of 2369 subjects (40% men) > or =35 years of age (mean, 59 years) without a history of stroke were obtained. Associations between stroke and each index were determined using Cox proportional hazards regression and the likelihood ratio (LR) test. During follow-up (mean, 11.7 years), 238 strokes occurred. The LR test showed that SBP and mean BP were significantly more strongly associated with total and ischemic stroke than DBP and PP (LR chi2 > or =9.3, P<0.01 for SBP/mean BP, LR chi2 < or =3.8, P> or =0.05 for DBP/PP). SBP tended to be more strongly associated with total/ischemic stroke than mean BP (LR chi2=3.8, P=0.05 for SBP, LR chi2 < or =0.2, P>0.6 for mean BP). PP tended to be slightly more strongly associated with ischemic stroke than DBP (LR chi2=7.5, P<0.01 for DBP, LR chi(2)=9.3, P<0.01 for PP), whereas DBP was significantly more strongly associated with hemorrhagic stroke than PP (LR chi2=9.2, P<0.01 for DBP, LR chi2=2.5, P=0.01 for PP). PP obtained from home BP measurements was weakly associated with stroke, whereas SBP showed the strongest association. Additionally, DBP and PP may be associated with different stroke types.