Sunlight and other determinants of circulating 25-hydroxyvitamin D levels in black and white participants in a nationwide US study

D. Michal Freedman, Elizabeth K. Cahoon, Preetha Rajaraman, Jacqueline M. Major, Michele M. Doody, Bruce H Alexander, Richard W. Hoffbeck, Michael G. Kimlin, Barry I. Graubard, Martha S. Linet

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

Circulating 25-hydroxyvitamin D (25(OH)D), a marker for vitamin D status, is associated with bone health and possibly cancers and other diseases; yet, the determinants of 25(OH)D status, particularly ultraviolet radiation (UVR) exposure, are poorly understood. Determinants of 25(OH)D were analyzed in a subcohort of 1,500 participants of the US Radiologic Technologists (USRT) Study that included whites (n = 842), blacks (n = 646), and people of other races/ethnicities (n = 12). Participants were recruited monthly (2008-2009) across age, sex, race, and ambient UVR level groups. Questionnaires addressing UVR and other exposures were generally completed within 9 days of blood collection. The relation between potential determinants and 25(OH)D levels was examined through regression analysis in a random two-thirds sample and validated in the remaining one third. In the regression model for the full study population, age, race, body mass index, some seasons, hours outdoors being physically active, and vitamin D supplement use were associated with 25(OH)D levels. In whites, generally, the same factors were explanatory. In blacks, only age and vitamin D supplement use predicted 25(OH)D concentrations. In the full population, determinants accounted for 25% of circulating 25(OH)D variability, with similar correlations for subgroups. Despite detailed data on UVR and other factors near the time of blood collection, the ability to explain 25(OH)D was modest.

Original languageEnglish (US)
Pages (from-to)180-192
Number of pages13
JournalAmerican journal of epidemiology
Volume177
Issue number2
DOIs
StatePublished - Jan 2013

Keywords

  • 25-hydroxyvitamin D
  • dietary supplements
  • race
  • seasons
  • sex
  • sunlight
  • ultraviolet rays
  • vitamin D

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