BMI, age affect correlation between sleep and hypertension

The link between sleep duration and hypertension risk appears to be mediated by age and body mass index (BMI), a recent study has found.

Researchers performed a population-based cross-sectional survey on 130,139 adults who were asked to accomplish surveys designed to collect information about sleep duration, hypertension and BMI status. Participants were grouped into three according to sleep duration: <7 hours (short sleepers; 32 percent), 7–9 hours (64 percent) and >9 hours (long sleepers; 4 percent).  

Logistic regression analysis confirmed the link between sleep duration and hypertension. Compared to those who met the recommended hours of sleep per night, short (odds ratio [OR], 1.25, 95 percent confidence intervals [CI], 1.21–1.29) and long (OR, 1.99, 95 percent CI, 1.83–2.15) sleepers were significantly more likely to develop hypertension. After adjusting for confounders, however, the risk only remained for short sleepers.

Age emerged as an important modifying factor. Among short sleepers, those in the 18–44-year age group were more likely to have hypertension (OR, 1.25, 95 percent CI, 1.16–1.35) than participants ≥65 years (OR, 1.09, 95 percent CI, 1.01–1.17). This effect was absent in middle-aged (aged 45–64 years) adults.

Long sleep, on the other hand, was associated with increased hypertension risk in the elderly (aged ≥65 years; OR, 1.45, 95 percent CI, 1.28–1.65) relative to participants in middle-age (OR, 1.24, 95 percent CI, 1.05–1.46). Long sleep was unrelated to hypertension risk in the youngest age group.

Disaggregation according to BMI also revealed important differences. Short sleep, for instance, was more predictive of hypertension in adults with normal BMI than in obese counterparts. The opposite was true for long sleep, which increased the risk of hypertension more strongly in overweight participants.