National Health and Nutrition Examination Survey

National Health and Nutrition Examination Survey. It is a major program of studies designed to assess the health and nutritional status of adults and children in the United States. Conducted by the National Center for Health Statistics, a division of the Centers for Disease Control and Prevention, the survey combines interviews and physical examinations to produce a critical dataset for public health policy. The data are used to determine the prevalence of major diseases and risk factors, from obesity to hypertension, and to inform national health objectives like Healthy People.

History and Purpose

The program originated in the early 1960s, evolving from earlier surveys conducted by the United States Public Health Service. A significant milestone was the National Health Survey Act of 1956, which authorized continuous monitoring of the nation's health. The modern, continuous survey format was launched in 1999, integrating what were previously separate periodic surveys. Its primary purpose is to provide statistical data that track health trends, support epidemiological research, and form the scientific basis for public health policies and regulations set by agencies like the Food and Drug Administration and the Environmental Protection Agency.

Survey Design and Methodology

The survey employs a complex, stratified, multistage probability sampling design to select a nationally representative sample of about 5,000 individuals each year from counties across the United States. Participation involves two main components: an in-home interview conducted by trained staff from the United States Census Bureau, followed by a standardized physical examination in a specially designed Mobile Examination Center. This methodology ensures the collection of both self-reported data and objective clinical measurements, allowing for the validation of health conditions and the assessment of biomarkers not obtainable through interviews alone.

Data Collection Components

The interview component gathers detailed information on demographics, socioeconomic status, diet through the What We Eat in America dietary recall, and health history. The examination component includes direct physical measurements such as height, weight, and blood pressure, along with sophisticated laboratory tests. These tests analyze blood and urine samples for indicators like cholesterol, lead, glycated hemoglobin for diabetes, and antibodies for infectious diseases such as hepatitis and SARS-CoV-2. Additional components may include tests for osteoporosis using dual-energy X-ray absorptiometry and assessments of cardiovascular health.

Key Findings and Impact

Data from the program have been instrumental in identifying and tracking major public health issues. Landmark findings include documenting the rise in obesity prevalence, leading to national initiatives, and identifying the dramatic decline in blood lead levels in children following the removal of lead from gasoline and paint. The survey's data on cholesterol levels and hypertension have directly influenced guidelines from the American Heart Association and the National Institutes of Health. It has also been critical in establishing reference ranges for growth in children, used worldwide in charts from the World Health Organization.

Data Access and Use

All data are made publicly available through the National Center for Health Statistics website, with strict protocols to protect participant confidentiality as mandated by the Health Insurance Portability and Accountability Act. Researchers from institutions like the Harvard T.H. Chan School of Public Health and the Mayo Clinic extensively use these datasets for peer-reviewed studies published in journals such as JAMA and The Lancet. The data also directly inform federal programs like the Supplemental Nutrition Assistance Program and are used for economic analyses by the Congressional Budget Office.

Category:Health surveys Category:Centers for Disease Control and Prevention Category:Statistics in the United States