The study was renewed in FY 1996. The cohort was expanded by the addition of 85 families identified through an affected proband, leading to a total of 300 families. These new cohort members were characterized in the fashion similar to that previously used. Follow-up was conducted on those initially recruited for apnea levels, blood pressure, body fat distribution, cranial facial dimensions, pulmonary function, and other factors of interest. For 450 of the individuals, follow-up extended through nine years. A nested case-control study was also conducted that included 24-hour ambulatory blood pressure monitoring and echocardiography. A principal analytic tool was variance component modeling.