Obesity does increase the risk of death after fractures, but the relationship is complex and influenced by multiple factors including metabolic health, bone healing capacity, and complications following surgery. People with obesity are more prone to fractures, and when fractures occur, their outcomes tend to be worse compared to individuals with normal weight.
One key reason obesity raises the risk of death after fractures is that excess body fat, especially visceral fat, negatively affects bone quality and healing. Although obesity was once thought to protect bones because heavier weight increases bone density, this protective effect is now understood to be limited. Visceral fat releases inflammatory molecules that promote bone breakdown and impair bone formation, leading to weaker bones that are more likely to fracture and heal poorly. Additionally, obesity is often accompanied by insulin resistance and type 2 diabetes, which further slow down bone healing and increase the risk of complications such as nonunion (failure of the bone to heal) or infections. These complications can lead to surgeries, prolonged immobilization, and even amputations in severe cases, all of which increase mortality risk.
After a fracture, especially hip fractures common in older adults, people with obesity face higher rates of postoperative complications. These include pulmonary problems, blood clots like deep vein thrombosis, strokes, and delirium. Morbid obesity (very high body mass index) is particularly associated with a greater likelihood of such complications and higher short-term mortality after surgery. For example, patients with morbid obesity have been shown to experience more pulmonary complications and strokes postoperatively, which contribute to increased death rates within 30 to 90 days after fracture surgery.
Interestingly, some treatments targeting obesity-related metabolic dysfunction, such as GLP-1 receptor agonists used in diabetes management, may reduce complications and improve outcomes after fractures. This suggests that managing the metabolic aspects of obesity could help mitigate some of the increased risks.
In summary, obesity increases the risk of death after fractures through a combination of poorer bone quality, impaired healing, and higher rates of postoperative complications. The inflammatory environment created by excess fat, coupled with metabolic diseases like diabetes, compromises recovery and raises mortality risk. Addressing these factors through medical management and careful surgical care is essential to improving survival and quality of life for people with obesity who suffer fractures.
