Lower serum vitamin D in obese children relative to children with normal body weights in Saudi Arabia

Abstract Purpose: Obesity is increasing in prevalence worldwide and represents a major international health burden. Pediatric obesity has increased during the prior two decades. Vitamin D plays important roles in promoting bone homeostasis and protecting against cardiovascular events. Several studies have linked vitamin D deficiency and obesity in adult populations. We sought to assess the relationship between serum vitamin D and obesity in children in Saudi Arabia. Materials and Methods: Pediatric outpatients who were 5-14 years of age were included in this study. Body mass index (BMI) was used to classify patients as follows: BMI<85th percentile was regarded as normal body weight; BMI between the 85th and 94th percentile was regarded as overweight; and BMI≥95th percentile was regarded as obese. Serum vitamin D was measured in all patients. Vitamin D deficiency was defined to be a vitamin D level<30 ng/ml. Results: Among the 65 patients included in this study, there were 24 patients with normal body weights and 41 overweight or obese patients. With respect to gender, there were 33 males and 32 female patients. Vitamin D deficiency was more common among overweight and obese patients than among patients with normal body weights; in particular, this deficiency was detected in 26 of the former patients and only 13 of the latter patients. Mean serum vitamin D (in nmol/l) was significantly greater for male patients (27.56±10.80) than for female patients (21.99±11.31; t(63)=-2.031; p=0.046). In addition, mean serum vitamin D (in nmol/l) was significantly greater in the Normal group (50th to 85th percentile in BMI; 29.33±13.97) than in the Overweight+Obese group (≥85th percentile in BMI; 22.17±8.58; t=2.272; p=0.030). Conclusions: Obesity is associated with a significantly lower serum vitamin D level. Additional studies are needed to confirm this finding.