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Vitamin D status and its relationship with parathyroid hormone and bone mineral status in older adolescents

Published online by Cambridge University Press:  07 March 2007

Alexis M. Willett*
Affiliation:
MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, CB1 9NL, UK
*
Corresponding author: Alexis Willett, fax +44 1223 437515, email A.M.Willett.01@cantab.net
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Abstract

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Osteoporosis is an important contributor to the global burden of disease, and in the UK alone results in one in three women and one in twelve men aged >50 years experiencing a fragility fracture. Optimising peak bone mass in early adulthood is thought to reduce osteoporosis risk by offsetting bone losses in later life. Ensuring sufficient vitamin D status (measured as 25-hydroxyvitamin D (25OHD) in plasma), among other factors, is believed to facilitate the achievement of optimum peak bone mass. Lower 25OHD is associated with a higher plasma concentration of parathyroid hormone (PTH). As PTH is associated with increased bone turnover and bone loss, maintenance of sufficient 25OHD is thought to have a protective effect on bone health. However, there is a lack of consensus internationally on what constitutes an optimum 25OHD concentration, and values between 30 and 80 nmol/l have been suggested. These values have been based on findings from various studies in adults in which PTH has been observed to plateau at a 25OHD concentration of >30 nmol/l; however, not all studies have found such a plateau. Although studies in younger adolescents (14–16 years) have shown an inverse relationship between PTH and 25OHD, the concentration of 25OHD required for achievement of optimum peak bone mass is unknown. The present review examines the evidence defining vitamin D insufficiency thresholds, and the relevance of such thresholds to adolescent bone health.

Type
Postgraduate Symposium
Copyright
Copyright © The Nutrition Society 2005

References

Abrams, SA, Copeland, KC, Gunn, SK, Stuff, JE, Clarke, LL & Ellis, KJ (1999) Calcium absorption and kinetics are similar in 7- and 8-year-old Mexican-American and Caucasian girls despite hormonal differences. Journal of Nutrition 129, 666671.Google Scholar
Ala-Houhala, M, Parviainen, MT, Pyykö, K & Visakorpi, JK (1984) Serum 25-hydroxyvitamin D levels in Finnish children aged 2 to 17 years. Acta Paediatrica Scandinavica 73, 232236.Google Scholar
Awumey, EMK, Mitra, DA, Hollis, BW, Kumar, R & Bell, NH (1998) Vitamin D metabolism is altered in Asian Indians in the southern United States: A clinical research center study. Journal of Clinical Endocrinology and Metabolism 83, 169173.Google Scholar
Ballabriga, A (2000) Morphological and physiological changes during growth: an update. European Journal of Clinical Nutrition 54, S1S6. Suppl. 1Google Scholar
Bass, S, Delmas, PD, Pearce, G, Hendrich, E, Tabensky, A & Seeman, E (1999) The differing tempo of growth in bone size, mass, and density in girls is region-specific. Journal of Clinical Investigation 104, 795804.Google Scholar
Bates, CJ, Carter, GD, Mishra, GD, O'Shea, D, Jones, J & Prentice, A (2003) In a population study, can parathyroid hormone aid the definition of adequate vitamin D status? A study of people aged 65 years and over from the British National Diet and Nutrition Survey. Osteoporosis International 14, 152159.Google Scholar
Binkley, N, Krueger, D, Cowgill, CS, Plum, L, Lake, E, Hansen, KE, DeLuca, HF & Drezner, MK (2004) Assay variation confounds the diagnosis of hypovitaminosis D: a call for standardization. Journal of Clinical Endocrinology and Metabolism 89, 31523157.Google Scholar
Bonjour, JP, Theintz, G, Law, F, Slosman, D & Rizzoli, R (1994) Peak bone mass Osteoporosis International S7 – S13Google Scholar
Burnand, B, Sloutskis, D, Gianoli, F, Cornuz, J, Rickenbach, M, Paccaud, F & Burckhardt, P (1992) Serum 25-hydroxyvitamin D: distribution and determinants in the Swiss population. American Journal of Clinical Nutrition 56, 537542.Google Scholar
Cadogan, J, Blumsohn, A, Barker, ME & Eastell, R (1998) A longitudinal study of bone gain in pubertal girls: anthropometric and biochemical correlates. Journal of Bone and Mineral Research 13, 16021612.Google Scholar
Chapuy, MC, Arlot, ME, Duboeuf, F, Brun, J, Crouzet, B, Arnaud, S, Delmas, PD & Meunier, PJ (1992) Vitamin D3 and calcium to prevent hip fractures in the elderly women. New England Journal of Medicine 327, 16371642.Google Scholar
Chapuy, MC, Pamphile, R, Paris, E, Kempf, C, Schlichting, M, Arnaud, S, Garneo, P & Meunier, P (2002) Combined calcium and vitamin D 3 supplementation in elderly women: confirmation of reversal of secondary hyperparathyroidism and hip fracture risk: The Decalyos II Study. Osteoporosis International 13, 257264.Google Scholar
Chapuy, MC, Preziosi, P, Maamer, M, Arnaud, S, Galan, P, Hercberg, S & Meunier, PJ (1997) Prevalence of vitamin D insufficiency in an adult normal population. Osteoporosis International 7, 439443.Google Scholar
Chen, TC, Parsons, KS, Lu, K, Mathieu, JS & Holick, MF (2000) An evaluation of the biologic activity and vitamin D receptor binding affinity of the photoisomers of vitamin D 3 and previtamin D 3. Journal of Nutritional Biochemistry 11, 267272.Google Scholar
Clemens, MR (1989) The problem of rickets in UK Asians. Journal of Human Nutrition and Dietetics 2, 105116.Google Scholar
Cole, TJ & Prentice, A (1992) Bone mineral measurements. British Medical Journal 305, 12231224.Google Scholar
Consensus Development Conference (1993) Diagnosis, prophylaxis and treatment of osteoporosis. American Journal of Medicine 94, 646650.Google Scholar
Cooper, C, Campion, G, Melton, LJ (1992) Hip fractures in the elderly: a world-wide projection. Osteoporosis International 2, 285289.Google Scholar
Cromer, B & Harel, Z (2000) Adolescents: at increased risk for osteoporosis. Clinical Pediatrics 39, 565574.Google Scholar
Davies, PS, Bates, CJ, Cole, TJ, Prentice, A & Clarke, PC (1999) Vitamin D: seasonal and regional differences in preschool children in Great Britain. European Journal of Clinical Nutrition 53, 195198.Google Scholar
Dawson-Hughes, B, Harris, SS & Dallal, GE (1997) Plasma calcidiol, season, and serum parathyroid hormone concentrations in healthy elderly men and women. American Journal of Clinical Nutrition 65, 6771.Google Scholar
Department of Health (1998) Nutrition and Bone Health: With Particular Reference to Calcium and Vitamin D London H. M. Stationery OfficeGoogle Scholar
Du, X, Greenfield, H, Fraser, DR, Ge, K, Trube, A & Wang, Y (2001) Vitamin D deficiency and associated factors in adolescent girls in Beijing. American Journal of Clinical Nutrition 74, 494500.Google Scholar
El-Hajj, G, Nabulsi, M, Choucair, M, Salamoun, M, Hajj, C, Kizirian, A & Tannous, R (2001) Hypovitaminosis D in healthy schoolchildren. Pediatrics 107, E53Google Scholar
Ellis, G, Woodhead, JS & Cooke, WT (1977) Serum-25-hydroxyvitamin-D concentrations in adolescent boys. Lancet i, 825828.Google Scholar
Fehily, AM, Coles, RJ, Evans, WD & Elwood, PC (1992) Factors affecting bone density in young adults. American Journal of Clinical Nutrition 56, 579586.Google Scholar
Feskanich, D, Willett, WC & Colditz, GA (2003) Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal women. American Journal of Clinical Nutrition 77, 504511.Google Scholar
Fewtrell, MS (2003) Bone densitometry in children assessed by dual x ray absorptiometry: uses and pitfalls. Archives of Disease in Children 88, 795798.Google Scholar
Fraser, DR (1994) Effect of calcium deficiency on vitamin D metabolism. In Nutrient Regulation during Pregnancy, Lactation and Infant Growth, 237241 [Allen, L, King, J, Lonnerdal, B, editors]. New York: Plenum Press.Google Scholar
Garrow, JS, James, WPT & Ralph, A (2000) Human Nutrition and Dietetics, 10th ed. Edinburgh: Churchill Livingstone.Google Scholar
Gilsanz, V (1998) Phenotype and genotype of osteoporosis. Trends in Endocrinology and Metabolism 9, 184190.Google Scholar
Ginty, F, Cavadini, C, Michaud, PA, Burckhardt, P, Baumgartner, M, Mishra, GD & Barclay, DV (2005a) Effects of usual nutrient intake and vitamin D status on markers of bone turnover in Swiss adolescents European Journal of Clinical NutritionGoogle Scholar
Ginty, F, Rennie, KL, Mills, L, Stear, SJ, Jones, SC & Prentice, A (2005b) Positive, site-specific associations between bone mineral status, fitness and time spent at high impact activities in 16–18 year-old boys. Bone 36, 101110.Google Scholar
Gonzalez, EA & Martin, KJ (1998) Calcium, phosphorus and vitamin D. In Handbook of Nutrition and the Kidney, pp. 87106 [Mitch, WE, Klahr, S, editors]. Philadelphia, PA: Lippincott-Raven.Google Scholar
Gregory, J & Lowe, S (2000) National Diet and Nutrition Survey: Young People Aged 4 to 18 Years. Vol. 1, Report of the Diet and Nutrition Survey. London: The Stationery Office.Google Scholar
Guillemant, J, Cabrol, S, Allemandou, A, Peres, G & Guillemant, S (1995) Vitamin D-dependent seasonal variation of PTH in growing male adolescents. Bone 17, 513516.Google Scholar
Le Guillemant, J, Maria, HT, Allemandou, A, Pérès, A, Guillemant, GS (2001) Wintertime vitamin D deficiency in male adolescents: effect on parathyroid function and response to vitamin D 3 supplements. Osteoporosis International 12, 875879.Google Scholar
Guillemant, J, Taupin, P, Le Allemandou, HT, A, Pérès, Guillemant, GS (1999) Vitamin D status during puberty in French healthy male adolescents. Osteoporosis International 10, 222225.Google Scholar
Gustavsson, A, Thorsen, K & Nordstrom, P (2003) A 3-year longitudinal study of the effect of physical activity on the accrual of bone mineral density in healthy adolescent males. Calcified Tissue International 73, 108114.Google Scholar
Haddad, JG (1999) The vitamin D binding protein and its clinical significance. In Vitamin D: Physiology, Molecular Biology and Clinical Applications, pp. 101108 [Holick, MF, editor]. Totowa, NJ: Humana Press.Google Scholar
Hampson, G, Martin, FC, Moffat, K, Vaja, S, Sankaralingam, S, Cheung, J, Blake, GM & Fogelman, I (2003) Effects of dietary improvement on bone metabolism in elderly underweight women with osteoporosis: a randomised controlled trial. Osteoporosis International 14, 750756.Google Scholar
Harris, SS, Dawson-Hughes, B (1998) Seasonal changes in plasma 25-hydroxyvitamin D concentrations of young American black and white women. American Journal of Clinical Nutrition 67, 12321236.Google Scholar
Heaney, RP (2003) Bone mineral content, not bone mineral density, is the correct bone measure for growth studies. American Journal of Clinical Nutrition 78, 350351.Google Scholar
Heaney, RP, Abrams, S, Dawson-Hughes, B, Looker, A, Marcus, R, Matkovic, V & Weaver, C (2000) Peak bone mass. Osteoporosis International 11, 9851009.Google Scholar
Heaney, RP, Davies, KM, Chen, TC, Holick, MF, Barger-Lux, MJ (2003) Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol. American Journal of Clinical Nutrition 77, 204210.Google Scholar
Holick, MF (1981) The cutaneous photosynthesis of previtamin D3: a unique photoendocrine system. Journal of Investigative Dermatology 77, 5158.Google Scholar
Holick, MF (1995) Environmental factors that influence the cutaneous production of vitamin D. American Journal of Clinical Nutrition 61 638S–645S Suppl.Google Scholar
Holick, MF (1996) Vitamin D and bone health. Journal of Nutrition 126 1159S – 1164SGoogle Scholar
Holick, MF (1999) Evolution, biologic functions, and recommended dietary allowances for vitamin D. In Vitamin D: Physiology, Molecular Biology, and Clinical Applications, pp. 116 [Holick, MF, editor]. Totowa, New Jersey: Humana Press.Google Scholar
Holick, MF (2001) Sunlight dilemma: risk of skin cancer or bone disease and muscle weakness. Lancet 357, 46.Google Scholar
Holick, MF (2004) Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis. American Journal of Clinical Nutrition 79, 362371.Google Scholar
Jacques, PF, Felson, DT, Tucker, KL, Mahnken, B, Wilson, PW, Rosenberg, IH & Rush, D (1997) Plasma 25-hydroxyvitamin D and its determinants in an elderly population sample. American Journal of Clinical Nutrition 66, 929936.Google Scholar
Jesudason, D, Need, AG, Horowitz, M, O'Loughlin, PD, Morris, HA & Nordin, BE (2002) Relationship between serum 25-hydroxyvitamin D and bone resorption markers in vitamin D insufficiency. Bone 31, 626630.Google Scholar
Jouanny, P, Guillemin, F, Kuntz, C, Jeandel, C & Pourel, J (1995) Environmental and genetic factors affecting bone mass. Similarity of bone density among members of healthy families. Arthritis Rheumatology 38, 6167.Google Scholar
Kantorovich, V, Gacad, MA, Seeger, LL & Adams, JS (2000) Bone mineral density increases with vitamin D repletion in patients with coexistent vitamin D insufficiency and primary hyperparathyroidism. Journal of Clinical Endocrinology and Metabolism 85, 35413543.Google Scholar
Krabbe, S, Transbøl, I & Christiansen, C (1982) Bone mineral homeostasis, bone growth, and mineralisation during years of pubertal growth: a unifying concept. Archives of Disease in Childhood 57, 359363.Google Scholar
Kristinsson, , Valdimarsson, G, Sigurdsson, G, Franzson, L, Olafsson, I & Steingrimsdottir, L (1998) Serum 25-hydroxyvitamin D levels and bone mineral density in 16–20 years-old girls: lack of association. Journal of Internal Medicine 243, 381388.Google Scholar
Kudlacek, S, Schneider, B, Peterlik, M, Leb, G, Klaushofer, K, Weber, K, Woloszczuk, W & Willvonseder, R (2003) Assessment of vitamin D and calcium status in healthy adult Austrians. European Journal of Clinical Investigation 33, 323331.Google Scholar
Kun, Z, Greenfield, H, Xueqin, D & Fraser, DR (2001) Improvement of bone health in childhood and adolescence. Nutrition Research Reviews 14, 114151.Google Scholar
Lamberg-Allardt, CJ, Outila, TA, Karkkainen, MU, Rita, HJ & Valsta, LM (2001) Vitamin D deficiency and bone health in healthy adults in Finland: could this be a concern in other parts of Europe. Journal of Bone and Mineral Research 16, 20662073.Google Scholar
Lawson, M, Thomas, M & Hardiman, A (1999) Dietary and lifestyle factors affecting plasma vitamin D levels in Asian children living in England. European Journal of Clinical Nutrition 53, 268272.Google Scholar
Lehtónen-Veromaa, M, Möttönen, T, Irjala, K, Kärkkäinen, M, Lamberg-Allardt, C, Hakola, P & Viikari, J (1999) Vitamin D intake is low and hypovitaminosis D common in healthy 9- to 15-year-old Finnish girls. European Journal of Clinical Nutrition 53, 746751.Google Scholar
Lehtónen-Veromaa, M, Möttönen, T, Nuotio, I, Irjala, K & Viikari, J (2002) The effect of conventional vitamin D 2 supplementation on serum 25(OH)D concentration is weak among peripubertal Finnish girls: a 3-y prospective study. European Journal of Clinical Nutrition 56, 431437.Google Scholar
Lips, P, Chapuy, MC, Dawson-Hughes, B, Pols, HAP & Holick, MF (1999) An international comparison of serum hydroxyvitamin D measurements. Osteoporosis International 9, 394397.Google Scholar
Looker, 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, 771777.Google Scholar
Lund, B, Sorensen, OH, Bishop, JE & Norman, AW (1980) Vitamin D metabolism in hypoparathyroidism. Journal of Clinical Endocrinology and Metabolism 51, 606610.Google Scholar
Malabanan, A, Veronikis, IE & Holick, MF (1998) Redefining vitamin D insufficiency. Lancet 351, 805806.Google Scholar
Margiloff, L, Harris, SS, Lee, S, Lechan, R, Dawson-Hughes, B (2001) Vitamin D status of an outpatient clinic population. Calcified Tissue International 69, 263267.Google Scholar
Meyer, HE, Smedshaug, GB, Kvaavik, E, Falch, JA, Tverdal, A & Pedersen, JI (2002) Can vitamin D supplementation reduce the risk of fracture in the elderly? A randomized controlled trial. Journal of Bone and Mineral Research 17, 709715.Google Scholar
Nakamura, K, Nashimoto, M, Hori, Y & Yamamoto, M (2000) Serum 25-hydroxyvitamin D concentrations and related dietary factors in peri- and postmenopausal Japanese women. American Journal of Clinical Nutrition 71, 11611165.Google Scholar
Nakamura, K, Nashimoto, M, Matsuyama, S & Yamamoto, M (2001) Low serum concentrations of 25-hydroxyvitamin D in young adult Japanese women: a cross sectional study. Nutrition 17, 921925.Google Scholar
National, Osteoporosis & Society, Online (2004) Facts and figures. http://www.nos.org.uk/osteo.aspGoogle Scholar
Norman, AW (1992) Bone biochemistry and physiology from the perspectives of the vitamin D endocrine system. Current Opinion in Rheumatology 4, 375382.Google Scholar
Norman, AW (1998) Receptors for 1(alpha), 25(OH) 2 D 3 : past, present and future. Journal of Bone and Mineral Research 13, 13601369.Google Scholar
O'Hare, AE, Uttley, WS, Belton, NR, Westwood, A, Levin, SD & Anderson, F (1984) Persisting vitamin D deficiency in the Asian adolescent. Archives of Disease in Childhood 59, 766770.Google Scholar
Oliveri, MB, Wittich, A, Mautalen, C, Chaperon, A & Kizlansky, A (2000) Peripheral bone mass is not affected by winter vitamin D deficiency in children and young adults from Ushuaia. Calcified Tissue International 67, 220224.Google Scholar
Outila, TA, Kärkkäinen, MUM, Lamberg-Allardt, CJE (2001) Vitamin D status affects serum parathyroid hormone concentrations during winter in female adolescents: associations with forearm bone mineral density. American Journal of Clinical Nutrition 74, 206210.Google Scholar
Parfitt, AM (1994) The two faces of growth: benefits and risks to bone integrity. Osteoporosis International 4, 382398.Google Scholar
Parsons, TJ, Prentice, A, Smith, EA, Cole, TJ & Compston, JE (1996) Bone mineral mass consolidation in young British adults. Journal of Bone and Mineral Research 11, 264274.Google Scholar
Patel, R, Collins, D, Bullock, S, Swaminathan, R, Blake, GM & Fogelman, I (2001) The effect of season and vitamin D supplementation on bone mineral density in healthy women: a double-masked crossover study. Osteoporosis International 12, 319325.Google Scholar
Prentice, A (2004) Diet, nutrition and the prevention of osteoporosis. Public Health Nutrition 7, 227243.Google Scholar
Prynne, CJ, Ginty, F, Paul, AA, Bolton-Smith, C, Stear, SJ, Jones, SC & Prentice, A (2004) Dietary acid-base balance and intake of bone-related nutrients in Cambridge teenagers. European Journal Clinical Nutrition 58, 14621471.Google Scholar
Raisz, LG (1999) Physiology and pathophysiology of bone remodeling. Clinical Chemistry 45, 13531358.Google Scholar
Reid, DM (2003) An overview of osteoporosis. In Nutritional Aspects of Bone Health, pp. 112 [New, SA, Bonjour, J-P, editors]. Cambridge: Royal Society of Chemistry.Google Scholar
Riggs, BL, Khosla, S, Melton, LJ III (1999) The assembly of the adult skeleton during growth and maturation: implications for senile osteoporosis. Journal of Clinical Investigation 104, 671672.Google Scholar
Root, AW (2002) Bone strength and the adolescent. Adolescent Medicine 13, 5372.Google Scholar
Rubin, LA, Hawker, GA, Peltekova, VD, Fielding, LJ, Ridout, R & Cole, DE (1999) Determinants of peak bone mass: clinical and genetic analyses in a young female Canadian cohort. Journal of Bone and Mineral Research 14, 633643.Google Scholar
Rucker, D, Allan, JA, Fick, GH & Hanley, DA (2002) Vitamin D insufficiency in a population of healthy western Canadians. Canadian Medical Association Journal 166, 15171524.Google Scholar
Russell, AS, Dennison, E & Cooper, C (2003) Epidemiology and public health impact of osteoporosis. In Nutritional Aspects of Osteoporosis, 1324 [New, SA, Bonjour, J-P, editors] Cambridge: Royal Society of Chemistry.Google Scholar
Saggese, G, Baroncelli, GI & Bertelloni, S (2001) Osteoporosis in children and adolescents: diagnosis, risk factors, and prevention. Journal of Pediatric Endocrinology and Metabolism 14, 833859.Google Scholar
Saggese, G, Baroncelli, GI & Bertelloni, S (2002) Puberty and bone development. Best Practice Research Clinical Endocrinology and Metabolism 16, 5364.Google Scholar
Salamone, LM, Dallal, GE, Zantos, D, Makrauer, F, Dawson-Hughes, B (1993) Contributions of vitamin D intake and seasonal sunlight exposure to plasma 25-hydroxyvitamin D concentration in elderly women. American Journal of Clinical Nutrition 58, 8086.Google Scholar
Scharla, SH, Scheidt-Nave, C, Leidig, G, Seibel, MJ & Ziegler, R (1995) Association between serum 25-hydroxyvitamin D and bone mineral density in a normal population sample in Germany. Challenges of Modern Medicine 7, 325328.Google Scholar
Sherman, SS, Hollis, BW & Tobin, JD (1990) Vitamin D status related parameters in a healthy population: The effects of age, sex and season. Journal of Clinical Endocrinology and Metabolism 71, 405413.Google Scholar
Sigurdsson, G, Franzson, L, Steingrimsdottr, L & Sigvaldason, H (2000) The association between parathyroid hormone, vitamin D and bone mineral density in 70-year old Icelandic women. Osteoporosis International 11, 10311035.Google Scholar
Silverberg, SJ, Shane, E, Dempster, DW & Bilezikian, JP (1999) The effects of vitamin D insufficiency in patients with primary hyperparathyroidism. American Journal of Medicine 107, 561567.Google Scholar
Slemenda, CW, Reister, TK, Hui, SL, Miller, JZ, Christian, JC & Johnston, CC (1994) Influences on skeletal mineralization in children and adolescents: Evidence for varying effects of sexual maturation and physical activity. Journal of Pediatrics 125, 201207.Google Scholar
Souberbielle, JC, Cormier, C, Kindermans, C, Gao, P, Cantor, T, Forette, F & Baulieu, EE (2001) Vitamin D status and redefining serum parathyroid hormone reference range for the elderly. Journal of Clinical Endocrinology and Metabolism 86, 30863090.Google Scholar
Stear, SJ, Prentice, A, Jones, SC & Cole, TJ (2003) Effect of a calcium and exercise intervention on the bone mineral status of 16–18 y-old adolescent girls. American Journal of Clinical Nutrition 77, 985992.Google Scholar
Szulc, P, Seeman, E & Delmas, PD (2000) Biochemical measurements of bone turnover in children and adolescents. Osteoporosis International 11, 281294.Google Scholar
Tangpricha, V, Pearce, EN, Chen, TC & Holick, MF (2002) Vitamin D insufficiency among free-living healthy young adults. American Journal of Medicine 112, 659662.Google Scholar
Tanner, JM (1962) Growth at Adolescence 2nd ed. Oxford Blackwell Scientific PublicationsGoogle Scholar
Thomas, MK, Lloyd-Jones, DM, Thadhani, RI, Shaw, AC, Deraska, DJ, Kitch, BT, Vamvakas, EC, Dick, IM, Prince, RL & Finkelstein, JS (1998) Hypovitaminosis D in medical inpatients. New England Journal of Medicine 338, 777783.Google Scholar
Trivedi, DP, Doll, R & Khaw, KT (2003) Effect of four monthly oral vitamin D3 (cholecalciferol) supplementation on fractures and mortality in men and women living in the community: randomised double blind controlled trial. British Medical Journal 326, 469Google Scholar
Vander, A, Sherman, J & Luciano, D (2001) Human Physiology: The Mechanisms of Body Function 8th ed. New York McGraw-HillGoogle Scholar
Vieth, R (1999) Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. American Journal of Clinical Nutrition 69, 842856.Google Scholar
Vieth, R & Carter, G (2001) Difficulties with vitamin D nutrition research: objective targets of adequacy, and assays for 25-hydroxyvitamin D. European Journal of Clinical Nutrition 55, 221222.Google Scholar
Vieth, R, Ladak, Y & Walfish, PG (2003) Age-related changes in the 25-hydroxyvitamin D versus parathyroid hormone relationship suggest a different reason why older adults require more vitamin D. Journal of Clinical Endocrinology and Metabolism 88, 185191.Google Scholar
Wang, MC, Crawford, PB, Hudes, M, Van Loan, M, Siemering, K & Bachrach, LK (2003) Diet in midpuberty and sedentary activity in prepuberty predict peak bone mass. American Journal of Clinical Nutrition 77, 495503.Google Scholar
Webb, AR, DeCosta, BR & Holick, MF (1989) Sunlight regulates the cutaneous production of vitamin D 3 by causing its photodegradation. Journal of Clinical Endocrinology and Metabolism 68, 882887.Google Scholar
Webb, AR & Holick, MF (1988) The role of sunlight in the cutaneous production of vitamin D 3. Annual Review of Nutrition 8, 375399.Google Scholar
Willett, AM (2004) Factors affecting vitamin D status in older adolescents and their relevance to bone health. PhD Thesis, University of Cambridge.Google Scholar
Willett, AM, Ginty, F & Prentice, A (2004) Effect of calcium supplementation on vitamin D status in 16–18 year old girls. Proceedings of the Nutrition Society 63 39AGoogle Scholar
Willett, AM, Ginty, F & Prentice, A (2005a) Calcium supplementation does not modify vitamin D status in 1618 year old boys Journal of Bone and Mineral ResearchGoogle Scholar
Willett, AM, Ginty, F, Prentice, A & Laidlaw, A (2005b) 25-Hydroxyvitamin D status and effects on PTH, bone metabolism markers and bone mineral status in 1618 year old boys and girls Journal of Steroid Biochemistry and Molecular BiologyGoogle Scholar
Woitge, HW, Scheidt-Nave, C, Kissling, C, Leidig-Bruckner, G, Meyer, K, Grauer, A, Scharla, SH, Ziegler, R & Seibel, MJ (1998) Seasonal variation of biochemical indexes of bone turnover: results of a population-based study. Journal of Clinical Endocrinology and Metabolism 83, 6875.Google Scholar
Woitge, HW & Seibel, MJ (2001) Biochemical markers to survey bone turnover. Rheumatic Disease Clinics of North America 27, 4980.Google Scholar