Vitamin D status of Irish adults: findings from the National Adult Nutrition Survey
Cashman, Kevin D.; Muldowney, Siobhan; McNulty, Breige A.; Nugent, Anne P.; Fitzgerald, Anthony P.; Kiely, Mairead E.; Walton, Janette; Gibney, Michael J.; Flynn, Albert
Date:
2012-08-12
Copyright:
© The Authors 2012. Published by Cambridge University Press (CUP) on behalf of The Nutrition Society
Citation:
Cashman, K. D., Muldowney, S., McNulty, B., Nugent, A., FitzGerald, A. P., Kiely, M., Walton, J., Gibney, M. J. and Flynn, A. (2013) 'Vitamin D status of Irish adults: findings from the National Adult Nutrition Survey', British Journal of Nutrition, 109(7), pp. 1248-1256. doi:10.1017/S0007114512003212
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.
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