Sleep and Cardiometabolic Health in Adults: Contributions of Lifestyle and Dietary Factors, Objective vs. Subjective Sleep, and Change in Sleep Habits

Sleep is necessary for cardiometabolic health, but compared to the 1980s, greater proportions of adults in developed countries are sleep deprived. The primary objectives of this dissertation were three-fold: i) to estimate the contributions of inflammation, oxidative stress, antioxidants, and physical activity levels to the causal relationships between sleep and cardiometabolic health; ii) to correlate objective vs. subjective measures of sleep, and determine if the correlations vary in subpopulations; and, iii) to estimate the risk of developing hypertension, diabetes, dyslipidemia and obesity due to changes in objectively measured sleep duration and efficiency in a 4 y follow-up. The US National Health and Nutritional Examination Survey and the Sleep Heart Health Study data were used. Mediation analyses, Pearsons correlations, and relative risk (RR) adjusting for age, sex, education, alcohol, smoking, marital status and body mass index were estimated. There are four important findings from this work. First, inflammation, oxidative stress, selected antioxidants, and lifestyle and moderate intensity activity levels contributed to some of the causal relationships between sleep and cardiometabolic health. Second, objective vs. subjective sleep measures correlates moderately but vary by sex, age, education, and obesity. Third, an increase in sleep duration increased the RR of developing hypertension by 29% in a 4 y follow-up. Finally, a decrease in sleep efficiency increased the RR of developing diabetes and dyslipidemia 57% and 65%, respectively. In summary, this work provides evidence that dietary and lifestyle factors lie on the causal pathway of several sleep and cardiometabolic health relationships, and thus explains their importance in cardiometabolic health. It also suggests adults perceive their sleep habits reasonably well, but co-morbidities and demographics affect their perception. This work also provides evidence that changes in sleep habits in a relatively short time increases the risk of developing hypertension, diabetes, and dyslipidemia. Therefore, optimizing the dietary habits, physical activity levels, and sleep behaviours can improve the cardiometabolic health of adults.