The association between lower limb fractures and weight gain in adults: a prospective analysis of body mass index trends

Abstract

Abstract Purpose Despite understanding the connection between obesity and fracture risk, there is limited research on the implications of lower limb fractures on subsequent changes in body mass index (BMI). Our study aimed to assess the impact of lower limb fractures on BMI alterations over an 18-month period. Methods A multi-center, prospective cohort study was conducted between January 2021 to June 2023, involving 494 adults with lower limb fractures. Participants were recruited within 2 weeks post-injury and were assessed for demographics, injury details, and weight at seven distinct time points. By 18 months, the primary outcome was the mean weight gain. Results The average age of the participants was 39 (± 12.7) with a baseline weight and BMI of 80.4 kg and 27.6, respectively. At the 18-month follow-up, 75% of patients experienced an average weight increase in 4 kg (± 5.39 kg), equating to a BMI rise of 1.39 (± 1.88). Most patients attributed weight changes to their injury, with nearly half expressing distress from their weight change. Only 37% believed that they had resumed their previous activity levels by the final follow-up. Approximately 31% of the patients sought some form of external weight management care in the form of nutritionist advice, training programs, medication and weight management procedures. Conclusions Lower limb fractures significantly affect weight gain over an 18-month period, with substantial psychological and physical consequences. Healthcare providers should anticipate potential weight gain post-fracture and incorporate strategies addressing both physical and mental aspects of rehabilitation to enhance recovery outcomes. Early and even immediate weight bearing may play a pivotal role in mitigating weight changes and returning the patient to their previous level of activity. Further detailed studies focusing on different fractures and postoperative interventions are recommended.