The association of blunted nocturnal blood pressure dip and stroke in a multiethnic population

Nondipping has been defined as a reduction in the mean systolic and diastol ic blood pressure (BP) of <10% from awake to sleep. We hypothesized that no ndipping might be associated with stroke in minority populations. We monito red BP over a 24 h period with an ambulatory device in 166 cases from a mul tiethnic population of stroke survivors (63 blacks, 61 non-Hispanic whites, and 42 Caribbean Hispanics, aged 69.5 +/- 11 years) and 217 community cont rol subjects (73 blacks, 107 non-Hispanic whites, and 67 Caribbean Hispanic s, aged 69 +/- 9 years). Prevalence of nondipping was significantly greater among cases than among control subjects (64% v 37%, P <.001). In a multipl e logistic regression model adjusted for traditional risk factors for strok e, nondipping conferred an increased risk for stroke. Probability of stroke associated with nondipping (odds ratio (OR) 2.5, confidence interval (CI) 1.6 to 4.0) was equal to that of traditional risk factors. Nondipping incre ased the chance of having a stroke in both non-Hispanic whites (OR 4.2, P < .001) and blacks/Caribbean Hispanics (OR 1.9, P =.03). The strength of the contribution of nondipping to stroke risk was similar in all ethnic groups. Nondipping was associated with stroke in both men and women. Given the pre vious reports that nondipping contributes to stroke risk in European and As ian populations, these data suggest that nondipping may be universally asso ciated with risk far stroke. Am J Hypertens 2000;13:1250-1255 (C) 2000 Amer ican Journal of Hypertension, Ltd.