Vitamin D state among overweight and obese infants

الملخص EN

Background: obesity is a risk factor for vitamin D deficiency, this relation was studied on adults and some children and adolescents yet no studies were performed in a younger age group. Aims : the current study was designed to assess the serum levels of 25-OH vitamin D among over weight and obese infants in order to detect hypovitaminosis D in this critical period of growth. Methods : Twenty five overweight and obese infants (based on their Z-score weight for length / height) were enrolled in the study after exclusion of any systemic disorders or drug history that would affect body weight or vitamin D levels, a cohort group of 15 age and sex matched normally growing infants served as controls.

All cases were subjected to detailed dietetic history followed by diet analysis and anthropometric measurements with calculation of Z-scores weight for age (WAZ), length / height for age (HAZ) and weight for length / height (WHZ) and BMI.

Radiological assessment to exclude rickets and to determine the bone age and laboratory investigations including serum calcium, phosphorous, alkaline phosphatase and 25-OH vitamin D were done. Results: The study revealed lower levels of vitamin D in overweight and obese infants compared to the controls with significantly higher rates of hypovitaminos D among them (44%) compared to controls (6.7%).

Correlation studies revealed significant negative correlations between serum levels of 25 OH vitamin D and both WHZ and BMI (r=-0.57, -0.56, P=0.003, 0.003respectively).

Further, a positive significant correlation between serum levels of 25 OH vitamin D and serum calcium (r = 0.68, p<0.001) and a negative significant correlation with alkaline phosphatase (r = -0.59, P=0.002) were detected among obese and over weight infants. Conclusion : we conclude that overweight and obese infants have an increased risk of hypovitaminosis D.

Thus, we recommend routine vitamin D estimation in overweight and obese infants with proper management of hypovitaminosis D aiming at proper bone mineralization as well fulfilling other functions of vitamin D in this critical period of growth.