van der Wielen RP, Lowik MR, van den BH, de Groot LC, Haller J, Moreiras O, van Staveren WA (1995)
Serum vitamin D concentrations among elderly people in Europe.
Lancet 346: 207-210
These findings show that free-living elderly Europeans, regardless of geographical location, are at substantial risk of inadequate vitamin D status during winter and that dietary enrichment or supplementation with vitamin D should be seriously considered during this season.