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December 10, 2007

Living longer with obesity means heavier burden for hospitals

Markus Schafer, left,
and Ken Ferraro

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Living longer with obesity can lead to both longer hospital stays and more avoidable trips to the hospital, according to two new studies from Purdue University.

"Americans are overweight, and there are numerous studies that cite the problems of obesity," said Ken Ferraro, a professor of sociology. "However, as the age at which people become obese continues to get younger, we wanted to know how living longer with obesity affects people.

"These findings could motivate young people to reverse the trend with healthy eating and activity and, if so, they may be able to avoid the consequences of chronic obesity."

Ferraro, along with graduate student Markus Schafer, studied how obesity influences hospitalizations by using 20 years of personal health data based on surveys linked to hospital records of more than 4,000 people ages 25-77. The data, from 1971-1992, was part of a federally funded national health and nutrition survey.

"In an economic sense, we have a major problem on our hands in terms of what we would project for today's overweight children and teenagers," said Ferraro, who is director of Purdue's Center on Aging and the Life Course. "In the past, people's weight peaked during late middle age. As more young people become obese, we may anticipate accumulated health problems by the time they are 40. If they are going to be obese for 30, 40 or 50 years, then the health-care costs associated with their adult medical needs will skyrocket. These findings are more evidence that we need to act now to reverse the obesity trend in our younger people. Although it is hard to project the future from these data, the likely scenarios portend a diabetes epidemic."

The study by Schafer and Ferraro examining the length of hospital stays appears in this month's Journal of Health and Social Behavior.

"Other research evaluating obesity and hospitalization has typically assessed short-term effects only, such as whether obese people are more likely to go to the hospital in the course of a year," said Schafer, who is in his third year of the dual-title doctoral program in sociology and gerontology. "We wanted to broaden the scope and look at people's hospitalization experience over time as well as their weight history. Examining body weight at only one point in their life doesn't paint a complete picture of the problem."

The studies' findings suggest that obesity must be addressed at a younger age because the longer a person lives with the disease, the greater the consequences. More than 60 percent of the American population is considered overweight or obese based on the body mass index, which is a formula determined by height and weight. Obesity can lead to chronic conditions, such as heart disease, hypertension and Type 2 diabetes, that can affect the quality of life or lead to morbidity.

Ferraro and Schafer found these obesity complications often were the reasons people were hospitalized. Once in the hospital, however, these illnesses alone were not sufficient to explain the amount of time people were staying, Ferraro said.

This month's study shows that people who lived longer as obese stayed in the hospital from a half to one day more than people of average weight. Obesity directly leads to longer stays because of more complicated care or surgery and because obesity can make it harder to use traditional clinical health assessments and measurements, Schafer said.

"Many surgical procedures become more difficult with a lot of excess fat," he said.

This study examined 20 years of data for 4,574 people ages 44-71 who experienced a total of 12,380 hospitalizations. Routine admissions for childbirth were excluded, as were nursing home admissions.

"One of the surprising findings is that, as we followed people over consecutive hospitalizations, we found that the length of one stay was related to the length of the next," Schafer said. "It was a spillover effect. For people with long-term obesity, hospitalization wasn't enough to slow down the problems; the problems continued from one hospitalization to the next as reflected by a continuation of longer stays.

"This raises other questions, including whether hospitals are effective in the way they deal with long-term obesity."

The researchers also accounted for the role aging plays.

"There is a tricky relationship between age and the duration of obesity because you really can't have a long duration of obesity unless you are older," Schafer said. "We adjusted our findings for age, and we know it's not just age that is contributing to longer hospital stays. Rather living with obesity for years has its own effect."

The second study, which followed 1,023 subjects who experienced a hospitalization that was considered avoidable, appeared in November's Archives of Internal Medicine, published by the American Medical Association. The authors found that obese individuals, ages 25-64, were almost twice as likely to be hospitalized compared to normal-weight subjects. Obese people have the highest likelihood, about 24 percent, of being hospitalized when it could have been avoided.

Appropriate primary care could have prevented these hospitalizations, Ferraro said. However, those who are overweight or obese may not have sought regular care because of embarrassment or other issues related to their weight. This may suggest the need for primary-care providers to be more sensitive to the specific problems obese patients encounter.

This research was funded by the National Institute on Aging.

Writer: Amy Patterson Neubert, (765) 494-9723,

Sources: Ken Ferraro, (765) 494-4707,

Markus Shafer, (765) 494-1631,

Purdue News Service: (765) 494-2096;

Purdue graduate student Markus Schafer, from left, and Ken Ferraro, a professor of sociology, studied how living longer with obesity can lead to both longer hospital stays and more avoidable trips to the hospital. The first study shows those who live longer as obese stayed in the hospital from half to one day more than people of average weight, and the second study revealed that obese individuals were more likely to be hospitalized when it could have been avoided. (Purdue News Service photo/David Umberger)

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ABSTRACT - Journal of Health and Social Behavior

Obesity and Hospitalization over the Adult Life Course:
Does Duration of Exposure Increase Use?

Markus H. Schafer and Kenneth F. Ferraro

Consistent with a new genre of research on life-course analyses of health-service use, this study explores the consequences of long-term exposure to a risk factor. Drawing from cumulative-disadvantage theory, the study examines whether obesity, especially chronic obesity, increases hospitalization admission and length of stay. Analyses make use of hospital records abstracted over 20 years from a national survey of adults 41 to 77 years of age at baseline (n=4,754). Multiple measures of body weight are used to calculate adult obesity duration. Results reveal that obesity increased hospital admissions and length of stay over the 20 years studied. Among persons obese at any time during the study, years of obesity also led to longer stays. The findings highlight the utility of measures of the duration of risk exposure for both life-course studies of health and tests of cumulative-disadvantage theory.

ABSTRACT - Archives of Internal Medicine

Long-term Obesity and Avoidable Hospitalization
Among Younger, Middle-aged, and Older Adults

Markus H. Schafer and Kenneth F. Ferraro

Background: Avoidable hospitalizations are considered to result from conditions that are preventable with timely and effective ambulatory care. We examined whether obesity, particularly long-term obesity, is associated with risk for and frequency of avoidable hospital stays.

Conclusions: As indicated by its association with avoidable hospitalizations, long-term obesity is a substantial risk for complications in medical care. Interventions should target obesity early in the life course to help improve lifelong delivery of ambulatory care and to reduce strains on health-care resources.

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