title: Vitamin D status of Irish adults: findings from the National Adult Nutrition Survey.
abstract: Previous national nutrition surveys in Irish adults did not include blood samples; thus, representative serum 25-hydroxyvitamin D (25(OH)D) data are lacking. In the present study, we characterised serum 25(OH)D concentrations in Irish adults from the recent National Adult Nutrition Survey, and determined the impact of vitamin D supplement use and season on serum 25(OH)D concentrations. Of the total representative sample (n 1500, aged 18+ years), blood samples were available for 1132 adults. Serum 25(OH)D was measured via immunoassay. Vitamin D-containing supplement use was assessed by questionnaire and food diary. Concentrations of serum 25(OH)D were compared by season and in supplement users and non-users. Year-round prevalence rates for serum 25(OH)D concentration < 30, < 40, < 50 and < 75 nmol/l were 6.7, 21.9, 40.1 and 75.6 %, respectively (11.1, 31.1, 55.0 and 84.0 % in winter, respectively). Supplement users had significantly higher serum 25(OH)D concentrations compared to non-users. However, 7.5 % of users had winter serum 25(OH)D < 30 nmol/l. Only 1.3 % had serum 25(OH)D concentrations >125 nmol/l. These first nationally representative serum 25(OH)D data for Irish adults show that while only 6.7 % had serum 25(OH)D < 30 nmol/l (vitamin D deficiency) throughout the year, 40.1 % had levels considered by the Institute of Medicine as being inadequate for bone health. These prevalence estimates were much higher during winter time. While vitamin D supplement use has benefits in terms of vitamin D status, at present rates of usage (17.5 % of Irish adults), it will have only very limited impact at a population level. Food-based strategies, including fortified foods, need to be explored.
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Republic of Ireland. k.cashman@ucc.ie
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Cashman
authors.forename: Siobhan
authors.initials: S
authors.lastname: Muldowney
authors.forename: Breige
authors.initials: B
authors.lastname: McNulty
authors.forename: Anne
authors.initials: A
authors.lastname: Nugent
authors.forename: Anthony P
authors.initials: AP
authors.lastname: FitzGerald
authors.forename: Mairead
authors.initials: M
authors.lastname: Kiely
authors.forename: Janette
authors.initials: J
authors.lastname: Walton
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gibney
authors.forename: Albert
authors.initials: A
authors.lastname: Flynn
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002112:Calcifediol / Q000097:blood*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004032:Diet / Q000009:adverse effects*; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D009752:Nutritional Status; D015995:Prevalence; D012621:Seasons; D014807:Vitamin D / Q000008:administration & dosage* / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D055815:Young Adult
chemical_list: D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol