To assess the effect of a weight-loss program on improving iron status in overweight and obese school-aged children.

The data were analyzed in overweight and obese children (7-11 years of age; 114 girls and 212 boys) with body mass index-for-age z-scores (BAZ) >1 from a weight-loss program. Schools were randomly divided into 2 groups: intervention and control. Children in the intervention group underwent a 1-year, nutrition-based comprehensive intervention weight-loss program. Anthropometric, dietary intake, and physical activity data were collected at baseline and follow-up (1 year). Iron status and inflammatory markers were assessed within a month.

In the intervention group, BAZ decreased more than that in the control group (−0.4 ± 0.7 vs −0.1 ± 0.6, P < .0001); and iron profiles and inflammation status were improved at follow-up. In multivariable linear regression models, a greater decrease of BAZ and inflammation factors predicted a better improvement of iron status. After adjustment of ΔBAZ, ΔC-reactive protein was significantly associated with Δserum ferritin (β: 1.89; 95% CI, 0.70-3.09; P = .002) and Δsoluble transferrin receptor (β: 0.88; 95% CI, 0.16-0.59; P = .017); Δinterleukin-6 was significantly associated with Δserum ferritin (β: 1.22; 95% CI, 0.64-1.79; P < .0001).

Iron status and inflammation were improved by weight reduction. The improvement in inflammatory markers during weight reduction was independently associated with improvements of iron status.