Endocrine Abstracts

Background: Children who are overweight and obese have a higher incidence of fracture, but it is unknown if this varies by fracture site. Indeed, obesity in adult women protects against forearm fracture, but increases the risk of humeral fractures. We aimed to determine if adiposity differed by fracture site in children with upper limb fractures.

Methods: Children aged 3–18 years were recruited within 60 days of fracture. Height, weight, waist circumference and triceps and subscapular skinfold thicknesses were measured. Fat percentage was calculated using the Slaughter equation and overweight/obesity defined using the International Obesity Taskforce definitions based on BMI z-score. Fractures were classified using the ICD10 into hand (phalanges, metacarpals, and/or carpals), forearm (radius and/or ulna), and upper arm (humerus and/or clavicle).

Results: 401 children (67.6% males) participated. 34.2, 50.6, and 15.2% had fractures of the hand, forearm, and upper arm respectively. Median age was similar in children with forearm (10.8 years) and upper arm fractures (9.8 years, P=0.30), but both groups were younger than those with hand fractures (13.4 years, P<0.001 for both).

21.1, 28.0, and 19.0% of children with hand, forearm and upper arm fractures were overweight/obese (P=0.21) and a waist circumference≥90th centile was present in 37.1, 44.4, and 19.6% of each group respectively (P=0.008).

After adjustment for age and sex, children with upper arm fractures had lower weight z-score (0.29±1.23 vs 0.70±1.08, P=0.047), BMI z-score (0.16±1.23 vs 0.68±1.05, P=0.004) and %fat z-score (−0.27±0.76 vs 0.22±0.82, P=0.004) than children with forearm fractures. Weight, BMI, and %fat z-scores were similar in children with hand and forearm or hand and upper arm fractures.

Conclusion: Adiposity was greater in children with forearm than upper arm fractures. Further studies are needed to determine whether higher adiposity increases forearm fracture risk or is protective against upper arm fracture.