Obesity and injury are major health burdens on society. Possible relationships between obesity and injury have recently been reported, but their nature and extent has been unclear. This report presents summary information from an overview of the existing literature to investigate obesity–injury relationships. It also surveys opportunities to fill relevant gaps in knowledge in Australia.

Does obesity alter risk of injury? 

Findings are mixed but most evidence suggests that obesity increases the risk of injury. Indications are that the probability of falls, trips or stumbles, and resulting musculoskeletal injury, rises with obesity. The increased risk of falls in the obese may be somewhat offset by the possible protective effects of fat mass as cushioning and of increased bone density in weight-bearing joints. Sleep apnoea increases road injury risk and is strongly associated with obesity. The interaction of obesity and injury risk in children is complex and evidence limited. Falls risk is higher for obese children, probably increasing rates of face, tooth and musculoskeletal injuries. Obesity is also a risk factor during pregnancy, with increased rates of injury to mother and baby. Workers’ obesity has been found to be associated with risk of workplace injury. The rising prevalence of obesity is widely seen as a risk factor for nurses and workers in other occupations that require lifting people, though direct evidence of risk was not found. The relationship of body mass and injury risk during sport is complicated by the diversity of sporting activities and by the fact that the usual BMI-based measure of obesity is not appropriate for many athletes, whose higher body mass index (BMI) can reflect increased muscle mass rather than fat.

Does obesity affect outcomes from injury? 

Average length of stay in hospital is significantly longer for obese injured patients than their leaner counterparts. Greater requirements for respiratory support have also been shown for injured obese patients relative to the non-obese. Also, obese injured patients are more likely to suffer certain complications of care during the period in hospital following injury. Risk of death after serious injury appears to be raised by obesity, though findings are mixed in the most severely injured cases.

Filling information gaps in Australia 

Findings of the literature review are mostly not specific to Australia and do not show the effect of obesity in association with injury on health burden or health service demand. The National Hospital Morbidity Database (NHMD), national surveys of health and other data sources have potential to be used to fill this gap.