Global vitamin D levels in relation to age, gender, skin pigmentation and latitude: an ecologic meta-regression analysis

Osteoporos Int. 2009 Jan;20(1):133-40. doi: 10.1007/s00198-008-0626-y. Epub 2008 May 6.

Abstract

We performed a meta-analysis of cross-sectional studies on serum 25(OH)D status globally. Serum 25(OH)D levels on average were 54 nmol/l, were higher in women than men, and higher in Caucasians than in non-Caucasians. There was no trend in serum 25(OH)D level with latitude. Vitamin D deficiency was widespread.

Introduction: We studied vitamin D status (expressed as serum 25-hydroxy-vitamin D [25(OH)D]) in native subjects worldwide.

Methods: Meta-analysis and meta-regression of studies reporting on 25(OH)D in healthy subjects retrieved from Pubmed, Embase and Web of Science using the terms "serum", "25-hydroxy-vitamin D", "cholecalciferol", and "human". A total of 394 studies were included.

Results: The mean 25(OH)D level was 54 nmol/l (95% CI: 52-57 nmol/l). Women had borderline significantly higher 25(OH)D levels than men, and Caucasians had higher levels than non-Caucasians. 25(OH)D levels were higher in subjects aged >15 years than in younger subjects. Unadjusted there was no significant decrease in 25(OH)D with latitude (slope of curve -0.03 +/- 0.12 nmol/l per degree latitude north or south of equator, p = 0.8). There was a significant decline with latitude for Caucasians (-0.69 +/- 0.30 nmol/l per degree, p = 0.02), but not for non-Caucasians (0.03 +/- 0.39 nmol/l per degree, p = 0.14). After adjustment for age, gender, and ethnicity, no overall correlation was present between 25(OH)D and latitude (-0.29 +/- 0.24 nmol/l per degree, p = 0.23).

Conclusion: There was no overall influence of latitude on 25(OH)D. However, in separate analyses 25(OH)D decreased with latitude in Caucasians but not in non-Caucasians. A widespread global vitamin D insufficiency was present compared with proposed threshold levels.

Publication types

  • Meta-Analysis

MeSH terms

  • Adolescent
  • Adult
  • Age Factors
  • Aged
  • Child
  • Cross-Sectional Studies
  • Ecology / methods
  • Ethnic Groups
  • European Continental Ancestry Group
  • Female
  • Global Health*
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Regression Analysis
  • Sex Factors
  • Skin Pigmentation / physiology*
  • Sunlight*
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D Deficiency / epidemiology
  • Vitamin D Deficiency / ethnology

Substances

  • Vitamin D
  • 25-hydroxyvitamin D