Effect of social support on nocturnal blood pressure dipping

OBJECTIVE: To determine if nocturnal blood pressure (BP) dipping among non-Hispanic blacks is influenced by social support. Non-Hispanic blacks have higher rates of cardiovascular morbidity and mortality from hypertension and are more likely to have ambulatory blood pressure (ABP) that remains high at night (nondipping). METHODS: A total of 68 non-Hispanic black normotensive and 13 untreated hypertensive participants (age 72 ± 10 years, 48% female) free of clinical cardiovascular disease completed 24-hour ABP monitoring and a questionnaire that included a modified version of the CARDIA Study Social Support Scale (CSSS). Nondipping was defined as a decrease of <10% in the ratio between average awake and average asleep systolic BP. Analyses were adjusted for age, gender, and systolic BP. RESULTS: The prevalence of nondipping was 26.8% in subjects in the highest CSSS tertile versus 41.1% in the lowest CSSS tertile (p = .009). On adjusted analysis, CSSS was analyzed as a continuous variable and remained independently and inversely associated with nondipping (odds ratio 0.27, 95% Confidence Interval 0.08-0.94, p = .04). CONCLUSIONS: Social support may be an important predictor of BP dipping at night. These findings suggest that social support may have positive health affects through physiologic (autonomic) pathways.