To investigate whether black and white adults benefit similarly from perceived social support in relation to blood pressure (BP) dipping during sleep.
The Interpersonal Support Evaluation List (ISEL, 12-item version), which measures the perceived availability of several types of functional social support, was examined for interactive effects with race on dipping of mean arterial pressure (MAP), systolic blood pressure (SBP), and diastolic blood pressure (DBP) derived from 24-hour ambulatory blood pressure monitoring (ABPM). The sample consisted of 156 young to middle-aged adults (61 blacks, 95 whites; mean age = 35.7 years).
Mean ISEL scores did not differ between racial groups. Controlling for age, body mass index (BMI), resting BP, and socioeconomic status (SES), the interaction of social support by race yielded associations with nighttime dipping in MAP and DBP (p < .001) as well as SBP (p < .01). As ISEL scores increased among white participants, the extent of dipping increased in MAP, SBP, and DBP (p < .01), explaining 10%, 10%, and 8% of the variance, respectively. Conversely, black participants exhibited associations between increasing ISEL scores and decreasing levels of dipping in MAP, SBP, and DBP (p < .05), accounting for 9%, 8%, and 8% of the variance, respectively.
As perceived social support increased, white adults received cardiovascular benefits as suggested by enhanced nocturnal dipping of BP, but black adults accrued risks as evidenced by blunted declines in BP during sleep.
BP = blood pressure; ISEL = Interpersonal Support Evaluation List; MAP = mean arterial pressure; SBP = systolic blood pressure; DBP = diastolic blood pressure; BMI = body mass index; SES = socioeconomic status; ABPM = ambulatory blood pressure monitoring.
From the Departments of Psychiatry (D.C.C., R.A.N., J.E.D.) and Medicine (M.G.Z.), University of California, San Diego, La Jolla, California.
Address correspondence and reprint requests to Denise C. Cooper, Department of Psychiatry, University of California San Diego, 9500 Gilman Dr., #0804, La Jolla, CA 92093-0804. E-mail: firstname.lastname@example.org
Received for publication April 25, 2008; revision received December 31, 2008.
Supported by the National Institutes of Health Grant HL36005 (J.E.D.) and Grant RR00827 (M.G.Z.), and partially supported by the San Diego EXPORT Center Grant P60MD00220.