Spring 2001 Issue
NHANES Takes Pulse - and Other Measurements - of Our Nation’s Health
Walk into any shopping mall food court or fast-food restaurant, and you will see people gobbling two-fisted burgers and greasy fries, washed down by sugary drinks. At home, TV shows are laced with ads for calorie-laden snacks and desserts.
While it might appear people are simply enjoying the good life in a land of plenty, according to recent research results by CDC’s National Health and Nutrition Examination Survey (NHANES), these people are also putting their health at risk. NHANES research documented an increase in weight among Americans, which, for many, can lead to serious health problems, including increased risk for heart disease, hypertension and diabetes. The NHANES team is investigating this problem - as well as other indicators of the nation’s health using three state-of-the-art mobile examination centers that travel simultaneously across the country.
“What makes NHANES unique is the depth and thoroughness of our research,” says Cliff Johnson, M.S.P.H., director of the National Center for Health Statistics’ NHANES. “It’s the only survey of its kind.”
Each examination center is staffed by a team of 17 professionals and is composed of four interlocking trailers containing as much sophisticated diagnostic and testing medical gear as a clinic in a major hospital. Inside there are rooms to test people’s hearing, eyesight, cardiovascular fitness, dental health, and much more. “We coordinate our efforts to get the most accurate data possible,” says examination center manager, Dan O’Dea. “And we do it in a manner that assures every participant feels comfortable. Since all of the teams train together, we also provide consistent information regardless of what city we are in.” In a typical 12-month period, the NHANES staff examines about 5,000 people.
But the examination centers do much more than a typical clinic. “The accumulated data supplies information on a broad variety of health issues,” says Johnson. “It also builds databases that policy makers and public health officials can use to implement either educational programs or intervention programs that can improve the health status of the U.S. population.”
NHANES was first established in 1956 under the National Health Survey Act to compile statistics and investigate the amount, distribution and effects of illness and disability in the United States. Over the years, NHANES staff have conducted clinical tests, measurements and physical examinations on randomly selected people of all ages, nationalities and economic strata.
Past NHANES surveys have produced many important conclusions resulting in major policy and health care changes in the United States. Because of NHANES,
- folic acid was added to foods to prevent birth defects,
- iron-fortified grain and cereals were proven effective to help correct iron deficiency
- Congress, the Environmental Protection Agency and other agencies phased out the use of lead in gasoline, thereby reducing the levels of lead found in blood,
- the Coast Guard was able to set specifications for personal flotation devices using body measurement data,
- and national, standardized growth charts were created for pediatricians to evaluate children’s growth; these charts have been adapted and adopted worldwide as a reference standard.
While in the past, researchers had to wait many years before gaining access to health status data to make statistical estimates, sophisticated sampling techniques and computerization can now give them virtual snapshots of the nation’s health on an annual basis.
For NHANES exams, people are screened using random sample selection techniques. Those selected participate in detailed household interviews. They are then invited to receive physical examinations and health and dietary interviews in the examination center. Home examinations are given to people unable to come to the center for the full examination.
The latest NHANES research has already produced some startling conclusions. Perhaps most importantly, the surveys have found that about 13 percent of children ages six to 11 are overweight, an increase of two percent since 1994. Also, the number of overweight teens between 12 to 19 has increased from 11 to 14 percent in the same period.
While results such as these are not released for each NHANES site, the patterns can indicate the extent of the problem for the nation as a whole and guide choices in policies and programs. From the food we eat, to the clothes we wear and the products we use, the information gathered by NHANES impacts our lives in many different ways.
- Mike Fillon