The NCHS is a portal for many sites for health data and statistics. For statistics on diseases and conditions use the NCHS Topics tab to get to FastStats. Surveys such as NHANES are included under the "Data Collection Systems" tab
The YRBSS provides statistics on health-risk behaviors that contribute to the leading causes of death and disability among youth and adults, and measures the prevalence of obesity and asthma and other priority health-related. Data is available for states and large cities.