Obesity Increases Risk of Injury on the Job

Having a body mass index (BMI) in the overweight or obese range increases the risk of traumatic workplace injury, according to researchers at the Johns Hopkins Bloomberg School of Public Health’s Center for Injury Research and Policy. Employer-sponsored weight loss and maintenance programs should be considered as part of a well-rounded workplace safety plan. The study was Advance Access published on May 7, 2007, by the American Journal of Epidemiology.

BMI is a measure of body fat based on an adult’s height and weight. It is used to screen for weight categories that may lead to health problems. According to the Centers for Disease Control and Prevention, a BMI below 18.5 is considered underweight, 18.5–24.9 is normal; 25–29.9 is overweight and over 30 is obese.

“Clearly, limited resources for workplace injury prevention and control should target the most prominent and modifiable risk factors, but we cannot neglect the fact that our study and other recently published studies support an association between BMI and the risk, distribution and prevalence of workplace injury,” said Keshia M. Pollack, PhD, MPH, lead author of the study and an assistant professor in the Bloomberg School of Public Health’s Department of Health Policy and Management.

The researchers used medical and injury surveillance data on hourly workers employed in eight plants of the same aluminum manufacturer to determine whether increased BMI was a risk factor for workplace injury. The plants were scattered across the United States. BMI was calculated using National Institutes of Health criteria. Employees were grouped into five categories: underweight, normal, overweight, obesity levels I and II and obesity level III.

Of the 7,690 workers included in the study, 29 percent were injured at least once between January 2, 2002, and December 31, 2004. Approximately 85 percent of the injured workers were classified as overweight or obese. More than 28 percent of injuries occurred among employees classified as overweight, 30 percent in the obese I and II category and almost 34 percent in the obese III category.

The severely obese group who had a BMI of greater than 40 also had the most injuries to the hand/wrist/finger (22 percent) when compared to the same injuries in the other weight categories. Almost 10 percent of all injuries in the obese III group were to the leg/knee, compared to 7 percent of workers classified as overweight, which was the next highest injury rate.

“We know that obesity prevention policies and programs in the workplace are important simply because of likely improvements in employee health,” said Pollack, the Leon S. Robertson Faculty Development Chair in Injury Prevention. “What we do not know is if obesity prevention in the workplace will also have the added benefit of improving injury rates and reducing lost work time. Evaluations of worksite health promotion and obesity prevention efforts should measure changes not only in employee health, but also traumatic injury.”

The researchers say that more work will be needed to test the effectiveness for reducing weight among hourly (non-office) employees who face a number of barriers to participating in worksite physical activity programs, such as the need to remove protective clothing for midday exercise and a lack of time because of additional employment or home responsibilities.

Keshia M. Pollack and Gary S. Sorock, both with the Johns Hopkins Bloomberg School of Public Health, and Martin D. Slade, Linda Cantley, Kanta Sircar, Oyebode Taiwo and Mark R. Cullen co-authored the study.

“Association between Body Mass Index and Acute Traumatic Workplace Injury in Hourly Manufacturing Employees” was supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute of Occupational Safety and Health, the NIOSH Education and Research Center for Occupational Safety and Health at the JHSPH, the Donaghue Foundation and the Network on Socioeconomic Status and Health of the John D. and Catherine T. MacArthur Foundation. Support was also provided by Alcoa Inc.

The Bloomberg School of Public Health’s Center for Injury Research and Policy is celebrating its 20th anniversary this year.