The relationship between obesity and injuries among US adults

Purpose. To quantify the relationship between body mass index (BMI) and rates of medically attended injuries by mechanism (overall, fall, motor vehicle, and sport-related) and by nature (strain/sprain, lower extremity fracture, and dislocations), and between BMI and injury treatment costs. Design. Cross-sectional analysis. Setting. The noninstitutionalized population of the United States. Subjects. The 1999-2000, 2000-2001, and 2001-2002 waves of the Medical Expenditure Panel Survey, a large, nationally representative dataset, were combined to create the analysis sample. The final sample included 42,304 adults. Measures. Medically attended injury rates by mechanism and nature of injury and related treatment costs. Analysis. Logistic regressions were used to separately estimate the odds of sustaining any injury by mechanism or by nature for overweight (25 <= BMI <= 29.9) and three categories of obese individuals compared with those who were normal weight. A second set of regressions tested whether, given that an injury occurred, obese individuals had greater injury treatment costs. Results. Slightly more than one in five adults sustain an injury each year that requires medical treatment. The odds of sustaining an injury are 15% (overweight) to 48% (Class III obesity) greater among those with excess weight. Conditional on sustaining an injury, BMI did not have a significant impact on injury treatment costs. Conclusion. Our findings show a clear association between BMI and the probability of sustaining an injury. If increasing BMI is causing the rise in injury rates, then the incidence of injuries, including those related to falls, sprains/strains, lower extremity fractures, and joint dislocations, are likely to increase as the prevalence of obesity increases.