Arachidonic acid status negatively associates with forearm bone outcomes and glucose homeostasis in children with overweight condition or obesity.

Long-chain polyunsaturated fatty acids are implicated in musculoskeletal health in adults. This study examined whether fatty acid status relates to bone health outcomes in children with overweight condition or obesity (BMI Z-score 3.1 ± 0.1, 9.0 ± 0.2 y, n=108). Non-dominant forearm bone density (distal 1/3rd), geometry (4% site) and soft tissue composition (66%) were assessed using dual-energy x-ray absorptiometry and peripheral quantitative computed tomography. Red blood cell (RBC) fatty acid profile and indices of glucose homeostasis were measured. Differences in outcomes among RBC arachidonic acid (AA, C20:4 n-6) tertiles were tested using mixed model ANOVA. Ultra-distal, mid- and total- distal forearm bone mineral content, adjusted for sex, age percentage body fat, race and forearm length were 10 to 13% greater in children in the first AA tertile relative to the third. Children in the second tertile had the highest bone cross-sectional area and estimated strength at the 66% radius. Muscle cross-sectional area was 15% lower in the third tertile compared to the first, along with higher fasting insulin concentrations (27%) and HOMA-IR (31%). Higher RBC AA status aligns with deficits in forearm bone mass, geometry, and muscle mass in children with excess adiposity and early signs of insulin resistance. • Higher arachidonic acid status is associated with lower forearm bone mass in children with overweight condition or obesity • Children with higher arachidonic acid status had increased fasting insulin concentrations and indices of insulin resistance.