Is vitamin D status associated with non-communicable disease risk in children? A cohort study

Background: Studies in children and adults have reported variations in 25-hydroxyvitamin D (25(OH)D), body mass index (BMI) and blood pressure (BP) over time. Furthermore, there has been a reported association of 25(OH)D with BMI, BP and lipid levels in some cross-sectional and longitudinal studies. Methods: This is a longitudinal study of a group of adolescents with measurements of 25(OH)D, BP, anthropometry and lipids at the ages of 11, 12 13, 15 and 18­20 years. For age-related changes, year 12 participants (n = 261) were matched with year 18­20 participants (n = 368), resulting in 200 paired participants. Longitudinal analyses using the Generalized Estimating Equations (GEE) comprised the following groups of participants, Year 11 (n = 288), Year 12 (n = 253), Year 13 (n = 292), Year 15 (n =238) and Year 18­20 (n = 368). The relationship of 25(OH)D with BMI, BP and lipid levels over a period of 10 years was assessed. Results: There were significant increases in mean BMI and BP, and decreases in 25(OH)D levels with age (all p-values < 0.0001).In females, systolic BP was significantly higher in older participants (18­20) years than younger participants (12 years), but 25(OH)D was significantly higher in younger than older participants. In males, there was significant increase in BP in participants between age 12 years and 18­20 years. 25(OH)D, total cholesterol (TC) and low-density lipoprotein (LDL-C) were significantly lower in 18­20-year-old participants compared with 12-year-old participants. Longitudinally, 25(OH)D was inversely associated with LDL-C. Conclusion: There is evidence of changes in 25(OH)D, BMI and BP in adolescents over a period of 10 years. After adjusting for covariates, BMI and LDL-C were significantly negatively associated with 25(OH)D, which suggests that vitamin D status might be associated positively with favourable lipid profiles in children and adolescents.