Serum levels of vitamin D, retinol, zinc, and CRP in relation to obesity among children and adolescents

Background The aim of this study was to examine the possible association between serum micronutrients (vitamin D, retinol, zinc), C-reactive protein (CRP), and obesity among children and adolescents. Methods Weight and height were measured and serum 25-hydroxy vitamin D, serum retinol, serum zinc, and CRP were measured in 2818 children and adolescents (6-17 years of age), and the data of 10 investigation sites in Zhejiang Province were used. The difference of micronutrients (vitamin D, retinol, zinc) and CRP among different nutritional status were explored by ANOVA and Chi-square test. The associated factors of micronutrients and CRP of overweight and obesity were explored by multifactor analysis. Results There were significant differences between male students and female students on BMI, 25(OH)D3, and CRP, and there were significant differences between children and adolescents and between students living in urban area and rural area on BMI, 25(OH)D3, retinol, and zinc(t > 1.96, p < 0.05). There were significant differences on 25(OH)D3 and CRP level among children and adolescents with different nutritional conditions (F = 2.612, 15.022, p < 0.05). In multifactor analysis, we found that female [odds ratio (OR) = 0.68, 95% CI 0.49-0.81], living in rural area (OR = 0.68, 95% CI 0.56-0.82), age (OR = 0.95, 95% CI 0.92-0.98), high CRP concentration (OR = 1.08, 95% CI 1.04-1.12) and appropriate retinol level (OR = 1.32, 95% CI 1.09-1.59) were associated with obesity compared to low/normal BMI. Conclusion Gender, living area, age, CRP concentration, and vitamin A status were associated with children and adolescents with overweight and obesity compared to low/normal BMI. More attention in the intervention of overweight and obesity should be paid to boys living in urban areas, and high serum concentration of CRP should also be concerned.