1.Bischoff-Ferrari, HA, Willett, WC, Wong, JB et al. (2009) Prevention of nonvertebral fractures with oral vitamin D and dose dependency: a meta-analysis of randomized controlled trials. Arch Intern Med 169, 551–561.
2.Bischoff-Ferrari, HA, Dawson-Hughes, B, Staehelin, HB et al. (2009) Fall prevention with supplemental and active forms of vitamin D: a meta-analysis of randomised controlled trials. BMJ 339, b3692.
3.Autier, P & Gandini, S (2007) Vitamin D supplementation and total mortality: a meta-analysis of randomized controlled trials. Arch Intern Med 167, 1730–1737.
4.Scientific Advisory Committee on Nutrition (2007) Update on Vitamin D: Position Statement by the Scientific Advisory Committee on Nutrition. London: The Stationery Office.
5.DeLuca, HF (2004) Overview of general physiologic features and functions of vitamin D. Am J Clin Nutr 80, 1689S–1696S.
6.Hoare, J, Henderson, L, Bates, CJ et al. (2004) The National Diet and Nutrition Survey: Adults Aged 19 to 64 Years. London: HMSO.
7.Dent, CE & Gupta, MM (1975) Plasma 25 hydroxyvitamin D levels during pregnancy in Caucasians and in vegetarian and non vegetarian Asians. Lancet 2, 1057–1060.
8.Finch, PJ, Ang, L, Colston, KW et al. (1992) Blunted seasonal variation in serum 25-hydroxy vitamin D and increased risk of osteomalacia in vegetarian London Asians. Eur J Clin Nutr 46, 509–515.
9.Lamberg-Allardt, C, Karkkainen, M, Seppanen, R et al. (1993) Low serum 25-hydroxyvitamin D concentrations and secondary hyperparathyroidism in middle-aged white strict vegetarians. Am J Clin Nutr 58, 684–689.
10.Outila, TA, Kärkkäinen, MUM, Seppänen, RH et al. (2000) Dietary intake of vitamin D in premenopausal, healthy vegans was insufficient to maintain concentrations of serum 25-hydroxyvitamin D and intact parathyroid hormone within normal ranges during the winter in Finland. J Am Diet Assoc 100, 434–441.
11.Chan, J, Jaceldo-Siegl, K & Fraser, GE (2009) Serum 25-hydroxyvitamin D status of vegetarians, partial vegetarians, and nonvegetarians: the Adventist Health Study-2. Am J Clin Nutr 89, S1686–S1692.
12.Davey, GK, Spencer, EA, Appleby, PN et al. (2003) EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33 883 meat-eaters and 31 546 non meat-eaters in the UK. Public Health Nutr 6, 259–268.
13.Roddam, AW, Neale, R, Appleby, P et al. (2007) Association between plasma 25-hydroxyvitamin D levels and fracture risk: the EPIC-Oxford study. Am J Epidemiol 166, 1327–1336.
14.Bingham, SA, Gill, C, Welch, A et al. (1994) Comparison of dietary assessment methods in nutritional epidemiology: weighed records v. 24 h recalls, food-frequency questionnaires and estimated-diet records. Br J Nutr 72, 619–643.
15.Bingham, SA, Cassidy, A, Cole, TJ et al. (1995) Validation of weighed records and other methods of dietary assessment using the 24 h urine nitrogen technique and other biological markers. Br J Nutr 73, 531–550.
16.Holland, B, Welch, AA & Unwin, ID (1991) McCance and Widdowson’s The Composition of Foods. Cambridge, UK: The Royal Society of Chemistry and Ministry of Agriculture, Fisheries, and Food.
17.Spencer, EA, Appleby, PN, Davey, GK et al. (2002) Validity of self-reported height and weight in 4808 EPIC–Oxford participants. Public Health Nutr 5, 561–565.
18.IDS OCTEIA Kit Literature (2002) 25-Hydroxy Vitamin D, Catalogue Number AC-57F1. Boldon, Tyne & Wear, UK: Immunodiagnostic Systems (IDS) Ltd.
19.UK Department of Health (1991) Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Report on Health and Social Subjects no. 41. London: HMSO.
20.Bischoff-Ferrari, H (2009) Vitamin D: what is an adequate vitamin D level and how much supplementation is necessary? Best Pract Res Clin Rheumatol 23, 789–795.
21.Ruston, D, Hoare, J, Henderson, L et al. (2004) Nutritional Status (Anthropometry and Blood Analytes), Blood Pressure and Physical Activity. London: TSO.
22.Hyppönen, E & Power, C (2007) Hypovitaminosis D in British adults at age 45 y: nationwide cohort study of dietary and lifestyle predictors. Am J Clin Nutr 85, 860–868.
23.Cashman, KD, Hill, TR, Lucey, AJ et al. (2008) Estimation of the dietary requirement for vitamin D in healthy adults. Am J Clin Nutr 88, 1535–1542.
24.Heaney, RP, Davies, KM, Chen, TC et al. (2003) Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol. Am J Clin Nutr 77, 204–210.
25.Clements, MR, Davies, M, Hayes, ME et al. (1992) The role of 1,25-dihydroxyvitamin D in the mechanism of acquired vitamin D deficiency. Clin Endocrinol (Oxf) 37, 17–27.
26.Engelsen, O, Brustad, M, Aksnes, L et al. (2005) Daily duration of vitamin D synthesis in human skin with relation to latitude, total ozone, altitude, ground cover, aerosols and cloud thickness. Photochem Photobiol 81, 1287–1290.
27.Hollis, BW (2008) Measuring 25-hydroxyvitamin D in a clinical environment: challenges and needs. Am J Clin Nutr 88, S507–S510.