National health and nutrition examination survey nhanes là gì
Over the years, NHANES data have been used to support public health policy with the goal of improving the health and nutritional status of the U.S. population. A few of the more notable examples include the use of NHANES data to:
All NHANES are cross-sectional surveys, conducted in a similar manner; and contain a core set of questions, physical examinations, and physiological tests. Blood and urine are collected from all subjects and tested for a variety materials, including micronutrients, markers for certain diseases, and environmental pollutants. Information is also collected about diseases and health status, diet, sociodemographics, occupation, and education. All data are collected through household interviews and laboratory examinations conducted in mobile examination centers (MEC). In addition to the core elements, each survey contains other components requested by various federal agencies that help plan and fund the survey. A significant change to the survey content was started with NHANES99-00 (conducted from 1999-2000) and will continue into the future. This change includes the testing of blood and urine for an extensive number of chemicals that are of public health concern. In past surveys a very limited number of chemicals (e.g., lead, cadmium) were tested. A now greatly expanded list of chemicals includes dioxins, furans, PCBs, pesticides, and pesticide metabolites (i.e., breakdown products), volatile organic compounds, heavy metals, plant estrogens, polyaromatic hydrocarbons, and markers for tobacco smoke. The list of specific chemicals will change in the future, as the needs of funding agencies change in response to public health concerns. Because of the complex design of NHANES, caution must be exercised when evaluating the data. Users must read the data file documentation before undertaking any analysis in order to understand details of the survey that could have significant impact on their results. For example, the use of sampling weights is recommended for all analyses because the sample design incorporates differential probabilities of selection of subjects into the survey. In addition, while many of the tests and questions are administered to all subjects, there are certain components and laboratory analyses that are performed on only a subsample (e.g., one-third or one-fourth) of all individuals. This subsampling must be accounted for in all analyses. History
Other Sources: For additional details, visit the NHANES 1999-2000 data release page at https://www.cdc.gov/nchs/about/major/nhanes/NHANES99_00.htm. For information on the sample design, weighting, and variance estimation methodology, review the NHANES 1999-2000 analytic guidelines at https://www.cdc.gov/nchs/data/nhanes/guidelines1.pdf. Additional InformationNHANES Documentations is Available from: National Technical Information Service, Springfield, VA; PB2003-104276 |