Obese people are more likely than normal-weight people to injure themselves

Jul 20 2005

Results from a new study suggest that extremely obese people are more likely than normal-weight people to injure themselves.

Researchers collected health and injury data during a one-year period on more than 2,500 adults living in Colorado. More than one out of four (26 percent) of the extremely obese male participants reported personal injuries, and more than one out of five (21.7 percent) extremely obese women also reported injuries.

By comparison, about 17 percent of normal-weight men reported injuries, as did nearly 12 percent of normal-weight women, said Huiyun Xiang, the study's lead author and an investigator with the Center for Injury Research and Policy at Columbus Children's Research Institute.

Although other studies have looked at the relationship between obesity and injury, those studies were conducted either among adults in highly structured work environments or high school students, Xiang said. The current study is one of the first to look at the risk of injury in the general population.

The results appear in the current issue of the American Journal of Preventive Medicine.

The researchers categorized study participants based on individual body mass index (BMI) measurements, which relate a person's weight to their height. The National Institutes of Health recommends that BMI be used to classify someone as underweight, at a normal weight, overweight or obese, said Xiang, who is also an assistant professor of pediatrics at Ohio State University.

In this study, people with a BMI lower than 18.5 were considered underweight, and those with a BMI of 18.5 to 24.9 were considered within a normal weight range. People with a BMI of 25 to 29.9 were considered overweight, but not obese. Participants with a BMI of 30 to 34.9 were considered obese, while those with a BMI of 35 or higher were considered extremely obese.

Overexertion and falls were the most common causes of non-fatal injuries among obese and extremely obese people in the study.

"Obesity may limit what a person can physically do," Xiang said. "People with such limitations are often at a higher risk for injury than healthy people."

He and his colleagues gathered data from the Colorado Behavioral Risk Factor Surveillance System, which is sponsored by the Centers for Disease Control and Prevention. Through telephone surveys, the system monitors lifestyles and behaviors related to the primary causes of mortality and morbidity. Of the 2,575 adults who agreed to participate in the study, a total of 370 reported injuries within a one-year period.

The extremely obese participants reported the most injuries, while underweight people reported the least.

About 17 percent of women listed as obese, but not extremely so - those with a BMI of 30 to 34.9 - reported injuries. But fewer than one out of 10 (9.3 percent) obese men reported injuries, a finding that puzzled the researchers.

"We had a fairly small number of participants in this category, which could have resulted in this smaller number for men," Xiang said. "We expected it to be higher."

More than half - 51.7 percent - of the injuries sustained by obese and extremely obese people happened inside the home. Transportation areas, such as store parking lots, bus stations and airports, came in a distant second, with 16.3 percent of all reported injuries happening there.

More than a third of the injuries (35.2 percent) were caused by acute overexertion. Falls took second place, causing 29.9 percent of the injuries.

Injury rates reported by people who were overweight - but not obese - were similar to those of normal-weight participants. Results showed that 16.3 percent of overweight men and 12.3 percent of overweight women reported injuries, compared to 16.8 percent of normal-weight men and 11.3 percent of normal-weight women.

Underweight participants - those with a BMI of 18.5 or lower - reported the least number of injuries.

With the exception of obese men, injury rates increased with BMI in both men and women.

"There is undeniably a link between obesity and injury risk in adults," Xiang said. "Efforts to promote optimal body weight may reduce not only the risk of chronic diseases, but also the risk of unintentional injuries."

Xiang conducted the work with Lorann Stallones, a professor and director of the Colorado Injury Control Research Center at Colorado State University. Coauthors included Ohio State colleagues Gary Smith, director of the Center for Injury Research and Policy at Columbus Children's Research Institute; J. R. Wilkins, a professor with the division of epidemiology and biostatistics in Ohio State's School of Public Health; and Guanmin Chen and Sarah Hostetler, both with Columbus Children's Research Institute.