1Vieth, R, Bischoff-Ferrari, H, Boucher, BJ, et al. (2007) The urgent need to recommend an intake of vitamin D that is effective. Am J Clin Nutr 85, 649–650.
2Holick, MF (2007) Vitamin D deficiency. N Engl J Med 357, 266–281.
3Hypponen, 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.
4Pal, BR, Marshall, T, James, C & Shaw, NJ (2003) Distribution analysis of vitamin D highlights differences in population subgroups: preliminary observations from a pilot study in UK adults. J Endocrinol 179, 119–129.
5Shaw, NJ & Pal, BR (2002) Vitamin D eficiency in UK Asian families: activating a new concern. Arch Dis Child 86, 147–149.
6Looker, AC, Dawson-Hughes, B, Calvo, MS, Gunter, EW & Sahyoun, NR (2002) Serum 25-hydroxyvitamin D status of adolescents and adults in two seasonal subpopulations from NHANES III. Bone 30, 771–777.
7Calvo, MS & Whiting, SJ (2003) Prevalence of vitamin D insufficiency in Canada and the United States: importance to health status and efficacy of current food fortification and dietary supplement use. Nutr Rev 61, 107–113.
8Bodnar, LM, Simhan, HN, Powers, RW, Frank, MP, Cooperstein, E & Roberts, JM (2007) High prevalence of vitamin D insufficiency in black and white pregnant women residing in the northern United States and their neonates. J Nutr 137, 447–452.
9Holick, MF (1995) Environmental factors that influence the cutaneous production of vitamin D. Am J Clin Nutr 61, Suppl. 3, 638S–645S.
10Salamone, LM, Dallal, GE, Zantos, D, Makrauer, F & Dawson-Hughes, B (1994) Contributions of vitamin D intake and seasonal sunlight exposure to plasma 25-hydroxyvitamin D concentration in elderly women. Am J Clin Nutr 59, 80–86.
11Webb, AR, Kline, L & Holick, MF (1988) Influence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin. J Clin Endocrinol Metab 67, 373–378.
12Brot, C, Vestergaard, P, Kolthoff, N, Gram, J, Hermann, AP & Sørensen, OH (2001) Vitamin D status and its adequacy in healthy Danish perimenopausal women: relationships to dietary intake, sun exposure and serum parathyroid hormone. Br J Nutr 86, Suppl. 1, S97–S103.
13McGrath, JJ, Kimlin, MG, Saha, S, Eyles, DW & Parisi, AV (2001) Vitamin D insufficiency in south-east Queensland. Med J Aust 174, 150–151.
14Harris, SS & Dawson-Hughes, B (1998) Seasonal changes in plasma 25-hydroxyvitamin D concentrations of young American black and white women. Am J Clin Nutr 67, 1232–1236.
15Haddad, JG & Stamp, TC (1974) Circulating 25-hydroxyvitamin D in man. Am J Med 57, 57–62.
16Hollis, BW (1996) Assessment of vitamin D nutritional and hormonal status: what to measure and how to do it. Calcif Tissue Int 58, 4–5.
17Bodnar, LM, Catov, JM, Simhan, HN, Holick, MF, Powers, RW & Roberts, JM (2007) Maternal vitamin D deficiency increases the risk of preeclampsia. J Clin Endocrinol Metab 92, 3517–3522.
18McGrath, J (2001) Does ‘imprinting’ with low prenatal vitamin D contribute to the risk of various adult disorders? Med Hypotheses 56, 367–371.
19Ellis, G & Dixon, K (1977) Sequential-saturation-type assay for serum 25-hydroxyvitamin D. Clin Chem 23, 855–862.
20Stamp, TC & Round, JM (1974) Seasonal changes in human plasma levels of 25-hydroxyvitamin D. Nature 247, 563–565.
21Zerwekh, JE (2004) The measurement of vitamin D: analytical aspects. Ann Clin Biochem 41, 272–281.
22Lissner, D, Mason, RS & Posen, S (1981) Stability of vitamin D metabolites in human blood serum and plasma. Clin Chem 27, 773–774.
23Braun, MM, Helzlsouer, KJ, Hollis, BW & Comstock, GW (1995) Prostate cancer and prediagnostic levels of serum vitamin D metabolites (Maryland, United States). Cancer Causes Control 6, 235–239.
24Corder, EH, Guess, HA, Hulka, BS, Friedman, GD, Sadler, M, Vollmer, RT, Lobaugh, B, Drezner, MK, Vogelman, JH & Orentreich, N (1993) Vitamin D and prostate cancer: a prediagnostic study with stored sera. Cancer Epidemiol Biomarkers Prev 2, 467–472.
25McGrath, J, Eyles, D, Mowry, B, Yolken, R & Buka, S (2003) Low maternal vitamin D as a risk factor for schizophrenia: a pilot study using banked sera. Schizophr Res 63, 73–78.
26Nomura, AM, Stemmermann, GN, Lee, J, Kolonel, LN, Chen, TC, Turner, A & Holick, MF (1998) Serum vitamin D metabolite levels and the subsequent development of prostate cancer (Hawaii, United States). Cancer Causes Control 9, 425–432.
27Niswander, K (1972) The Collaborative Perinatal Study of the National Institute of Neurological Diseases and Stroke: The Women and their Pregnancies. Philadelphia, PA: WB Saunders.
28Horst, RL, Reinhardt, TA & Hollis, BW (1990) Improved methodology for the analysis of plasma vitamin D metabolites. Kidney Int Suppl 29, S28–S35.
29Alvarez, JC & De Mazancourt, P (2001) Rapid and sensitive high-performance liquid chromatographic method for simultaneous determination of retinol, α-tocopherol, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in human plasma with photodiode-array ultraviolet detection. J Chromatogr B Biomed Sci Appl 755, 129–135.
30Myrianthopoulos, NC & French, KS (1968) An application of the U.S. Bureau of the Census socioeconomic index to a large, diversified patient population. Soc Sci Med 2, 283–299.
31StataCorp (2003) Stata Statistical Software: Release 8.0. College Station, TX: Stata Corporation.
32Holick, MF (1987) Photosynthesis of vitamin D in the skin: effect of environmental and life-style variables. Fed Proc 46, 1876–1882.
33Nesby-O'Dell, S, Scanlon, KS, Cogswell, ME, Gillespie, C, Hollis, BW, Looker, AC, Allen, C, Doughertly, C, Gunter, EW & Bowman, BA (2002) Hypovitaminosis D prevalence and determinants among African American and white women of reproductive age: third National Health and Nutrition Examination Survey, 1988–1994. Am J Clin Nutr 76, 187–192.
34Stroud, LR, Solomon, C, Shenassa, E, Papandonatos, G, Niaura, R, Lipsitt, LP, Lewinn, K & Buka, SL (2007) Long-term stability of maternal prenatal steroid hormones from the National Collaborative Perinatal Project: still valid after all these years. Psychoneuroendocrinology 32, 140–150.
35Hollis, BW & Pittard, WB III (1984) Evaluation of the total fetomaternal vitamin D relationships at term: evidence for racial differences. J Clin Endocrinol Metab 59, 652–657.
36Lee, JM, Smith, JR, Philipp, BL, Chen, TC, Mathieu, J & Holick, MF (2007) Vitamin D deficiency in a healthy group of mothers and newborn infants. Clin Pediatr 46, 42–44.
37van der Meer, IM, Karamali, NS, Boeke, AJP, Lips, P, Middelkoop, BJC, Verhoeven, I & Wuister, JD (2006) High prevalence of vitamin D deficiency in pregnant non-Western women in The Hague, Netherlands. Am J Clin Nutr 84, 350–353.
38Millen, AE, Dodd, KW & Subar, AF (2004) Use of vitamin, mineral, nonvitamin, and nonmineral supplements in the United States: The 1987, 1992, and 2000 National Health Interview Survey results. J Am Diet Assoc 104, 942–950.
39Calvo, MS, Whiting, SJ & Barton, CN (2004) Vitamin D fortification in the United States and Canada: current status and data needs. Am J Clin Nutr 80, Suppl. 6, 1710S–1716S.
40Holick, MF (2004) Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis. Am J Clin Nutr 79, 362–371.