September 01, 2004
CHAPEL HILL — People who are obese face not only a greater risk of becoming sick in the first place, they also will remain longer in the hospital, on average, when compared with people of more normal weight, a new University of North Carolina at Chapel Hill study concludes.”This study is unique because it shows for the first time on a national basis that obese individuals stay longer in hospitals than healthy-weight individuals,” said Dr. Claire Zizza, postdoctoral fellow at the Cecil G. Sheps Center for Health Services Research. “The longer hospital stays for the former patients were evident despite the general trend over time toward shorter hospital stays.”

Zizza and colleagues examined how long people remained hospitalized in the United States from the 1970s to the 1990s using detailed data from the federally funded National Health and Nutrition Examination Survey’s Epidemiologic Followup Survey, which began with 14,407 U.S. residents and included four follow-up surveys through 1992.

“Over the years we studied, we found that obese people, particularly those with a body mass index of 35 or higher, had lengths of stays that were roughly 50 percent to 130 percent longer than healthy-weight individuals,” Zizza said.

The association between body mass index, a measure of how heavy someone is for how tall they are, and length of hospital stay varied over time, she said.

A report on the findings appears in the September issue of the American Journal of Public Health. Co-authors are Drs. Amy H. Herring, June Stevens and Barry M. Popkin of the UNC schools of public health and medicine and the Carolina Population Center.

Not surprisingly, people who were excessively thin — those with a body mass index of below 18.5 — also faced somewhat extended hospital stays relative to people of normal weights during part of the years studied, Zizza said. She and her colleagues found about 200 hospitalizations among almost 300 underweight people between 1986 and 1992.

Physicians and other health professionals consider a body mass index of between 18.5 and 25 to be normal.

“Increases in obesity have the potential to severely tax the health-care system, particularly given our results indicating that obese individuals have longer hospital stays,” Zizza said. “In all likelihood, treatment and prevention of obesity will reduce use of hospital care and the subsequent health-care costs associated with the obesity epidemic.”

Stevens, professor of nutrition and epidemiology, is serving as principal investigator for the coordinating center of a $34 million national study designed to improve physical fitness levels of U.S. girls to promote their health and reduce their risk of obesity. Half of all adolescent girls here fail to get enough vigorous exercise to maintain their health long-term.

Multiple previous studies have linked obesity with increased risk of heart disease, stroke, diabetes, premature joint problems and other illnesses, Stevens said. Obesity has reached all-time record levels in the United States for both sexes, all ages and all races.

The School of Public Health-based research effort she leads, the Trial of Activity in Adolescent Girls (TAAG), will determine if it is possible to reverse at least part of the inactivity trend in girls. UNC and six other universities are sharing the $34 million from the National Heart, Lung and Blood Institute.

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This article was researched and written by David Williamson of UNC News Services.

Note: Zizza can be reached via cell phone at (919) 353-9711. Stevens can be reached at (919) 966-1065 or

For further information please contact Emily Smith either by phone at 919.966.8498 or by email at


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