Vitamin D Status and Its Determinants in Adolescents From the Northern Ireland Young Hearts 2000 Cohort

Br J Nutr. 2008 May;99(5):1061-7. doi: 10.1017/S0007114507842826. Epub 2008 Jan 15.

Abstract

Despite recent concerns about the high prevalence of sub-clinical vitamin D deficiency in adolescents, relatively few studies have investigated the underlying reasons. The objective of the present study was to investigate the prevalence and predictors of vitamin D inadequacy among a large representative sample of adolescents living in Northern Ireland (54-55 degrees N). Serum concentrations of 25-hydroxyvitamin D (25(OH)D) were analysed by enzyme-immunoassay in a subgroup of 1015 of the Northern Ireland Young Hearts 2000 cohort; a cross-sectional study of 12 and 15 year-old boys and girls. Overall mean 25(OH)D concentration throughout the year was 64.3 (range 5-174) nmol/l; 56.7 and 78.1 nmol/l during winter and summer, respectively. Reported intakes of vitamin D were very low (median 1.7 microg/d). Of those adolescents studied, 3 % and 36 % were vitamin D deficient and inadequate respectively, as defined by serum 25(OH)D concentrations < 25 and < 50 nmol/l. Of the subjects, 46 % and 17 % had vitamin D inadequacy during winter and summer respectively. Gender differences were also evident with 38 % and 55 % of boys and girls respectively classified as vitamin D inadequate during winter (P < 0.001). Predictors of vitamin D inadequacy during winter were vitamin D intake and gender. In conclusion, there is a high prevalence of vitamin D inadequacy in white-skinned adolescents in Northern Ireland, particularly during wintertime and most evident in girls. There is a clear need for dietary recommendations for vitamin D in this age group and for creative strategies to increase overall vitamin D status in the population.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adolescent Nutritional Physiological Phenomena
  • Calcium, Dietary / administration & dosage
  • Child
  • Epidemiologic Methods
  • Female
  • Humans
  • Male
  • Northern Ireland / epidemiology
  • Seasons
  • Sex Factors
  • Vitamin D / administration & dosage
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / epidemiology*
  • Vitamin D Deficiency / etiology

Substances

  • Calcium, Dietary
  • Vitamin D
  • 25-hydroxyvitamin D