Relationship between 24-H blood pressure and sleep disordered breathing ina normotensive community sample

Sleep disordered breathing (SDB) and hypertension are commonly associated. In this study, we assessed how longitudinal measures of SDB predict a 24-h ambulatory blood pressure monitoring (ABPM) profile. Participants (n = 82) were recruited from a community-based urban (26% African American) sample a nd included family members of patients with laboratory diagnosed SDB (cases ) and family members of neighborhood control subjects evaluated at baseline and at 5 years. Nearly all participants were normotensive and were not rec eiving therapy for SDB. During both examinations, the respiratory distress index (RDI) was assessed with overnight in-home polysomnography. Seated blo od pressure (BP) was assessed at a baseline examination (ti) and after a 5- year follow-up period (t(5)). when 24-h ABPM also was performed. The change in RDI (t(5)-t(1)) over 5 years was significantly associated wit h 24-h mean systolic blood pressure (SBP) (P = .04), 24-h maximum diastolic blood pressure (DBP) (P = .03), sleep mean SBP (P = .05) sleep mean DBP (P < .05), and sleep maximum SBP (P = .02). Regression analysis revealed that average 24-h mean arterial pressure (MAP) and mean 24-h DBP were each best predicted by change in RDI explaining 5% of the variance in these 24-h BP readings, and by current smoking status. After accounting for these variabl es, BP was not predicted by any of the other potential confounders (all P > .10). Mean RDI (averaged between t(5) and t(1)) was associated with mean M AP, mean SBP, and maximal SBP measured during sleep. This study documents f or the first time the association between changes in sleep apnea activity a nd BP and in a community-based normotensive sample. Further long-term evalu ation of the effects of these findings and the long-term consequences of hy pertension are needed. (C) 2001 American Journal of Hypertension, Ltd.