Although the SHHS is a prospective cohort study, the cross-sectional findings will provide new information on patterns of sleep and sleep-disordered breathing in the general population. Consequently, initial analyses will be descriptive and will also address cross-sectional associations of sleep-disordered breathing with prevalent cardiovascular disease and quality of life and with risk factors for cardiovascular disease. Longitudinal analyses will address sleep-disordered breathing as a predictor of cardiovascular outcomes and change in blood pressure.