As we age, our relative proportion of body fat mass increases, while skeletal muscle mass and quality decreases. These age-related body composition changes have important implications for numerous public health issues, including falls and fall-related injuries. Obese older adults fall at higher rates than non-obese counterparts but have reduced risk of low-trauma fracture, particularly hip fracture, in part due to greater bone mineral density (BMD) and shock-absorbing soft tissue. Nonetheless, with the confluence of obesity epidemics and ageing populations in Australia and internationally, at least half of patients presenting with osteoporotic fractures are overweight or obese. Sarcopenia, the age-related loss of skeletal muscle mass, quality and function is associated with increased risk of both falls and fracture, and we have demonstrated that obese older adults with co-morbid sarcopenia (“sarcopenic obese”) do not similarly benefit from the protective effect for osteoporotic fractures observed in those with obesity alone. This may be explained by higher falls rates and significantly decreased BMD relative to patients with obesity alone, and potentially also greater microarchitectural deterioration of bone.
Primary management strategies for obesity include weight loss through caloric restriction, and in the case of morbid obesity, bariatric surgery. Both strategies, but particularly bariatric surgery, result in significant loss of bone mass and increased incidence of fracture leading some to question their safety for older patients. Risk of fracture may be greatest in older patients who lose higher relative amounts of muscle mass during weight loss. Engaging in resistance training programs, while ensuring adequate intakes of protein, vitamin D and calcium during caloric restriction, may reduce weight loss-associated declines in bone and muscle mass and therefore minimise subsequent fracture risk. This presentation will discuss risk factors for fracture in obese and sarcopenic older adults, and evidence-based interventions for improving bone health in these individuals.