[Vitamin D, iodine and iron status in children with obesity]

Active longevity and the prevention of alimentary diseases are priority areas of public policy. The prevalence of childhood obesity is steadily increasing, and this condition is associated with complex micronutrient imbalances. A comprehensive assessment of vitamin and trace element status in obese children living in the Siberian Federal District of the Russian Federation has not been conducted over the past 10 years, making this study particularly relevant. The objective of the study was to assess the vitamin D, iodine, and iron status of primary school-age children with exogenous-constitutional obesity.

A case-control study was conducted at medical institutions in Barnaul from June to December 2025. A total sample of 100 children aged 7-10 years were examined: the main group (n=60) included children with grades I-III obesity, and the control group (n=40) included healthy peers with normal body weight. The level of vitamin D (enzyme-linked immunosorbent assay) and ferritin (chemiluminescent immunoassay) were measured in blood serum, and the iodine level was determined in a single morning urine sample (cerium-arsenite method).

The groups were comparable by gender (the proportion of boys was 53.3-55.0%) and age (p>0.05). Children with obesity showed a statistically significant decrease in the level of 25-hydroxyvitamin D (30.8 [27.1; 34.2] versus 44.2 [39.0; 53.7] ng/ml in the control group, p<0.05). The median values of ferritin level (50.9 [38.9; 64.1] versus 47.2 [41.6; 55.8] ng/ml) and ioduria (427.0 [383.9; 460.5] versus 344.2 [289.0; 406.1] μg/l) did not differ in the compared groups (p>0.05). The incidence of vitamin D deficiency (<30 ng/ml) in the main group was 43.3 versus 22.5% in the control group (p=0.03), and iron deficiency (<30 ng/ml) was determined in 6.7% versus 10.0% (p<0.05). No iodine deficiency (<100 μg/l) was detected in the studied groups.

In the group of children with exogenous-constitutional obesity, almost every second child was diagnosed with vitamin D deficiency, which was the most common micronutrient deficiency. Ferritin level showed no statistically significant differences in the prevalence of iron deficiency. Urinary iodine levels reflected high iodine excretion in children in both groups.