Is vitamin D deficiency in obese youth a risk factor for less weight loss during a weight loss program?

Abstract

Background: Vitamin D deficiency is common in obese adolescents and a risk factor for insulin resistance. We investigated if prevailing serum 25-OH vitamin D might predict the body fat loss in a group of obese adolescents undergoing a resi dential weight loss program. Methods: In 92 (35 male) obese adolescents (aged 10.6–19 years) undergoing a residential weight loss program in Belgium, fasting serum 25-OH vitamin D ( 25-OH-D), insulin, glucose and lipid levels were measured and body composition was assessed by dual-energy X-ray absorptiometry (DXA). Results: Baseline median (range) serum 25-OH-D level was 17.7 μg/L (3.8 –41.8). In total, 55 adolescents had a serum 25-OH-D below 20 μg/L. In 31 adolesc ents with a low baseline 25-OH-D level, median increase in serum 25-OH-D was 2. 4 μg/L (−4.2 to 7.2) after 10 months. This resulted in normal 25-OH-D levels in seve n adolescents, whereas median BMI decreased with 1.0 SDS and body fat percentage dimin ished with 9.9%. Obese adolescents with or without a 25-OH-D level below or abov e 20 μg/L at baseline had similar changes in body weight, BMI SDS, body fat percentag e and body fat mass at the end of the program. The change in serum 25-OH-D did not cor relate with change in serum insulin, BMI SDS or body fat percentage and body fat mass . Conclusion: Vitamin D deficiency was present in 55 out of 92 obese adolesce nts at the start of the summer. Serum 25-OH-D concentration did not predict chan ges in body fat loss after a residential weight loss program.

Keywords

• vitamin d
• obesity
• adolescence
• weight loss program