Self-reported sleep impairment and the metabolic syndrome among African Americans

African Americans (AA) experience a high mortality from cardiovascular disease (CVD), even without an increase in the prevalence of the metabolic syndrome (MetS). The potential role of sleep impairment in this phenomenon has not been studied. The current study examined the relationship between self-reported sleep and MetS components among AAs. Sleep variables included total sleep quality and specific symptoms: loud snoring, difficulty breathing, and sleep duration.

Anthropometric (BMI, BP, waist circumference, body fat percent) and biologic (fasting glucose, triglycerides, total cholesterol, and HDL) measures were obtained from 248 community-recruited AA (63% female; mean age 44 years). The Pittsburgh Sleep Quality Index (PSQI), a 19-item scale with a total sleep quality score and 7 subscales, was used to assess self-reported sleep quality. Analyses were controlled for age and sex.

PSQI total sleep quality predicted neither presence of MetS (Beta=.04, P=.29) nor individual CVD variables. However, symptomatic snoring corresponded with MetS (Beta=.38, SE=.12, P<.001; OR: 2.57), as well as with fasting glucose, BMI, body fat percentage, and waist circumference.

Among AA, overall sleep quality as self-reported may not contribute to MetS, but symptomatic snoring appears to be important. Further work in this area should focus on sleep at the symptomatic level, and include racial and sex variables, as well as physiologic and etiologic mechanisms.