Relationship between 24-H blood pressure and sleep disordered breathing in a 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 and 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 receiving therapy for SDB. During both examinations, the respiratory distress index (RDI) was assessed with overnight in-home polysomnography. Seated blood pressure (BP) was assessed at a baseline examination (t,) and after a 5-year follow-up period (t5), when 24-h ABPM also was performed. The change in RDI (t5-t1) over 5 years was significantly associated with 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 variables, BP was not predicted by any of the other potential confounders (all P > .10). Mean RDI (averaged between t5 and t1) was associated with mean MAP, mean SBP, and maximal SBP measured during sleep. This study documents for the first time the association between changes in sleep apnea activity and BP and in a community-based normotensive sample. Further long-term evaluation of the effects of these findings and the long-term consequences of hypertension are needed.