Skip to main content

Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment: Symposium on ‘Diet and bone health’

  • Susan A. Lanham-New (a1)

Throughout the life cycle the skeleton requires optimum development and maintenance of its integrity to prevent fracture. Bones break because the loads placed on them exceed the ability of the bone to absorb the energy involved. It is now estimated that one in three women and one in twelve men aged >55 years will suffer from osteoporosis in their lifetime and at a cost in the UK of >£1·7×109 per year. The pathogenesis of osteoporosis is multifactorial. Both the development of peak bone mass and the rate of bone loss are determined by key endogenous and exogenous factors. Ca supplements appear to be effective in reducing bone loss in women late post menopause (>5 years post menopause), particularly in those with low habitual Ca intake (<400 mg/d). In women early post menopause (<5 years post menopause) who are not vitamin D deficient, Ca supplementation has little effect on bone mineral density. However, supplementation with vitamin D and Ca has been shown to reduce fracture rates in the institutionalised elderly, but there remains controversy as to whether supplementation is effective in reducing fracture in free-living populations. Re-defining vitamin D requirements in the UK is needed since there is evidence of extensive hypovitaminosis D in the UK. Low vitamin D status is associated with an increased risk of falling and a variety of other health outcomes and is an area that requires urgent attention. The role of other micronutrients on bone remains to be fully defined, although there are promising data in the literature for a clear link between vitamin K nutrition and skeletal integrity, including fracture reduction.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the or variations. ‘’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment
      Available formats
      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about sending content to Dropbox.

      Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment
      Available formats
      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about sending content to Google Drive.

      Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment
      Available formats
Corresponding author
Corresponding author: Dr Susan Lanham-New, fax +44 1483 686401, email
Hide All
1.Parfitt AM (1990) Osteomalacia and related disorders. In Metabolic Bone Disease and Clinically Related Disorders, 2nd ed., pp. 329396 [Avioli LV and Krane SM editors]. Philadelphia, PA: WB Saunders.
2.Loveridge N & Lanham-New SA (2008) Bones and ageing. In British Nutrition Foundation Taskforce on Nutritional Aspects of Ageing [Mathers J and Buttriss J editors]. London: Blackwell Publishing (In the Press).
3.Eastell R (1999) Pathogenesis of postmenopausal osteoporosis. In Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism, 4th ed., pp. 260262 [Favus MJ editor]. London: Williams & Wilkins.
4.Consensus Development Conference (1991) Diagnosis, prophylaxis and treatment of osteoporosis. Am J Med 90, 107110.
5.Consensus Development Conference (1993) Diagnosis, prophylaxis and treatment of osteoporosis. Am J Med 94, 646650.
6.Heaney RP, Abrams S, Dawson-Hughes B, Looker A, Marcus R, Matkovic V & Weaver C (2000) Peak bone mass. Osteoporos Int 11, 9851009.
7.van Staa TP, Dennison EM, Leufkens HG & Cooper C (2001) Epidemiology of fractures in England and Wales. Bone 29, 517522.
8.Dennison E & Cooper C (2007) Lifestyle and constitutional risk factors. In Managing Osteoporosis, pp. 6980 [Lanham-New SA, O'Neill T, Morris R, Skeleton D and Sutcliffe A editors]. Oxford: Clinical Publishing.
9.Torgerson DJ, Iglesias C & Reid DM (2001) Economics of Osteoporosis. Key Advance Series. London: Aesculapius Press.
10.World Health Organization (1994) Study Group on Assessment of Fracture Risk and Its Application to Screening and Postmenopausal Osteoporosis. Report of a WHO Study Group. Technical Report Series no. 84. Geneva: WHO.
11.Abrams SA (2003) Normal acquisition and loss of bone mass. Horm Res 60, 7176.
12.Smith R (2003) Calcium and the bone minerals. In Human Nutrition and Dietetics, pp. 451489 [James WPT and Garrow J editors]. Cambridge: Cambridge University Press.
13.National Institutes of Health Consensus Development Panel (2000) Osteoporosis Prevention, Diagnosis, and Therapy. NIH Consens Statement Online 2000 March 27–29 17(1), 136. (accessed January 2006).
14.The National Osteoporosis Society (2006) What is osteoporosis? (accessed January 2006).
15.Royal College of Physicians (2000) Osteoporosis Clinical Guidelines for Prevention and Treatment. London: Royal College of Physicians of London.
16.Department of Health (1998) Nutrition and Bone Health: With Particular References to Calcium and Vitamin D. Report on Health and Social Subjects 49. London. H. M. Stationery Office.
17.Food and Nutrition Board of the Institute of Medicine (1997) Dietary Reference Intakes: Calcium, Phosphorus, Magnesium, Vitamin, and Fluoride. Washington, DC: National Academy Press.
18.Prentice A, Schoenmakers I, Laskey MA, de Bono S, Ginty F & Goldberg GR (2006) Nutrition and bone growth and development. Proc Nutr Soc 65, 348360.
19.Abrams SA (2005) Calcium supplementation during childhood: long-term effects on bone mineralization. Nutr Rev 63, 251255.
20.Ward KA, Roberts SA, Adams JE, Lanham-New SA & Mughal MZ (2007) Calcium supplementation and weight bearing physical activity – do they have a combined effect on the bone density of pre-pubertal children? Bone 41, 496504.
21.Ralston S (2007) Genetics of osteoporosis. In Managing Osteoporosis, pp. 8194 [Lanham-New SA, O'Neill T, Morris R, Skeleton D and Sutcliffe A editors]. Oxford: Clinical Publishing.
22.Seeman E & Hopper J (1997) Genetic and environmental components of the population variance in bone density. Osteoporos Int 7, S10S16.
23.Langman CB (2005) Genetic regulation of bone mass: from bone density to bone strength. Pediatr Nephrol 20, 352355; Epublication 5 January 2005.
24.Lorentzon M, Mellstrom D & Ohlsson C (2005) Age of attainment of peak bone mass is site specific in Swedish men – The GOOD study. J Bone Miner Res 20, 12231227; Epublication 7 March 2005.
25.Nieves J (2007) Calcium and vitamin D. In Managing Osteoporosis, pp. 2133 [Lanham-New SA, O'Neill T, Morris R, Skeleton D and Sutcliffe A editors]. Oxford: Clinical Publishing.
26.Rozen GS, Rennert G, Dodiuk-Gad RP, Rennert HS, Ish-Shalom N, Diab G, Raz B & Ish-Shalom S (2003) Calcium supplementation provides an extended window of opportunity for bone mass accretion after menarche. Am J Clin Nutr 78, 993998.
27.Bonjour JP, Ammann P, Chevalley T, Ferrari S & Rizzoli R (2003) Nutritional aspects of bone growth: an overview. In Nutritional Aspects of Bone Health, pp. 111128 [New SA and Bonjour JP editors]. Cambridge: Royal Society of Chemistry.
28.Chevalley T, Rizzoli R, Hans D, Ferrari S & Bonjour JP (2005) Interaction between calcium intake and menarcheal age on bone mass gain: an eight-year follow-up study from prepuberty to postmenarche. J Clin Endocrinol Metab 90, 4451; Epublication 26 October 2004.
29.Abrams SA, Copeland KC, Gunn SK, Gundberg CM, Klein KO & Ellis KJ (2000) Calcium absorption, bone mass accumulation and kinetics increase during early pubertal development in girls. J Clin Endocrin Metab 85, 18051809.
30.Wolff J (1892) Das Gesetz der Transformation der Knochen (The Law of Bone Remodelling). Berlin: Verlag von August Hirschwald.
31.Frost HM (1987) Bone ‘mass’ and the ‘mechanostat’: a proposal. Anat Rec 219, 19.
32.Nurmi-Lawton JA, Baxter-Jones ADJ, Mirwald R, Bishop JA, Taylor P, Cooper C & New SA (2004) Evidence of sustained skeletal benefits from impact-loading exercise in young adolescent females: a 3-year longitudinal study. J Bone Miner Res 19, 314322.
33.Fuchs RK, Bauer JJ & Snow CM (2001) Jumping improves hip and lumbar spine bone mass in prepubescent children: A randomized controlled trial. J Bone Miner Res 16, 148156.
34.Valdimarsson O, Linden C, Johnell O, Gardsell P & Karlsson M (2006) Daily physical education in the school curriculum in prepubertal girls during 1 year is followed by an increase in bone mineral accrual and bone width – Data from the Prospective Controlled Malmo Pediatric Osteoporosis Prevention Study. Calcif Tissue Int 78, 6571.
35.Specker BL (1996) Evidence for an interaction between calcium intake and physical activity on changes in bone mineral density. J Bone Miner Res 11, 15391544.
36.Specker B & Binkley T (2003) Randomized trial of physical activity and calcium supplementation on bone mineral content in 3- to 5-year-old children. J Bone Miner Res 18, 885892.
37.Bass SL, Naughton G, Saxon L, Iuliano-Burns S, Daly R, Briganti EM, Hume C & Nowson C (2007) Exercise and calcium combined results in a greater osteogenic effect than either factor alone: A blinded randomized placebo-controlled trial in boys. J Bone Miner Res 22, 458464.
38.Dawson-Hughes B (2004) Calcium and vitamin D for bone health in adults. In Nutrition and Bone Health, pp. 197210 [Holick MF and Dawson-Hughes B editors]. Totowa, NJ: Humana Press.
39.Heaney RP (2000) There should be a dietary guideline for calcium. Am J Clin Nutr 71, 658670.
40.Dawson-Hughes B, Dallal GE, Krall EA, Sadowski L, Sahyoun N & Tannenbaum S (1990) A controlled trial of the effect of calcium supplementation on bone density in postmenopausal women. N Engl J Med 323, 878883.
41.Goulding A & Grant A (2007) Nutritional strategies to optimize bone health throughout the life course. In Managing Osteoporosis, pp. 320 [Lanham-New SA, O'Neill T, Morris R, Skeleton D and Sutcliffe A editors]. Oxford: Clinical Publishing.
42.Shea B, Wells G, Cranney A et al. (2002) Osteoporosis Methodology Group and The Osteoporosis Research Advisory Group. Meta-analysis of therapies for post-menopausal osteoporosis. VII Meta-analysis of Ca supplementation for the prevention of postmenopausal osteoporosis. Endocr Rev 23, 552559.
43.Ho SC, Chen YM, Woo JL & Lam SS (2004) High habitual calcium intake attenuates bone loss in early post-menopausal Chinese women: an 18-month follow up study. J Clin Endocrinol 89, 21662170.
44.Suzuki Y, Davison KS & Chilibeck PD (2003) Total calcium intake is associated with cortical bone mineral density in a cohort of postmenopausal women not taking oestrogen. J Nutr Health Aging 7, 296299.
45.Nieves JW, Komar L, Cosman F & Lindsay R (1998) Calcium potentiates the effect of oestrogen and calcitonin on bone mass: review and analysis. Am J Clin Nutr 67, 1824.
46.Holick MF (2007) Vitamin D deficiency. N Engl J Med 357, 266281.
47.Scientific Advisory Committee on Nutrition (2007) Update on Vitamin D. Position Statement by the Scientific Advisory Committee on Nutrition. London: The Stationery Office; available at
48.Calvo MS, Whiting SJ & Barton CN (2005) Vitamin D intake: a global perspective of current status. J Nutr 135, 310316.
49.Veith R, Bischoff-Ferrari H, Boucher BJ et al. (2007) The urgent needs to recommend an intake of vitamin D that is effective. Am J Clin Nutr 85, 649650.
50.Finch S, Doyle W, Lowe C, Bates CJ, Prentice A, Smithers G & Clarke PC (1998) National Diet and Nutrition Survey of People Aged 65 Years and Over. London: H. M. Stationery Office.
51.Gregory J, Lowe S, Bates CJ, Prentice A, Jackson LV, Smithers G, Wenlock R & Farron M (2000) National Diet and Nutrition Survey of People Aged 4–18 Years. vol. 1. Report of the Diet and Nutrition Survey. London: The Stationery Office.
52.Henderson L, Gregory J & Swan G (2002) National Diet and Nutrition Survey: Adults Aged 19–64 Years. vol. 1: Types and Quantities of Foods Consumed. London: The Stationery Office.
53.Hypponen E & Power C (2007) Hypovitaminosis D in British adults at age 45 y: nationwide cohort study or dietary and lifestyle predictors. Am J Clin Nutr 85, 860888.
54.Holick MF (1994) Vitamin D: new horizons for the 21st century. Am J Clin Nutr 60, 619630.
55.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. H. M. Stationery Office.
56.Lanham-New SA, Thompson RL, More J, Brooke-Wavell K, Hunking P & Medici E (2007) Importance of vitamin D, calcium and exercise to bone health with specific reference to children and adolescents. Nutr Bull 32, 364377.
57.Cashman K (2007) Other key nutritional factors. In Managing Osteoporosis, pp. 4965 [Lanham-New SA, O'Neill T, Morris R, Skeleton D and Sutcliffe A editors]. Oxford: Clinical Publishing.
58.Ashwell M, Stone E, Mathers J et al. (2008) Review of the nutrition and bone health projects funded by the Food Standards Agency – have they helped to inform public health policy? Br J Nutr (In the Press).
59.Underwood JL & DeLuca HF (1984) Vitamin D is not directly necessary for bone growth and bone mineralization. Am J Physiol Endocrinol Metab 246, E492E498.
60.Boland R (1986) Role of vitamin D in skeletal muscle function. Endocr Rev 7, 434447.
61.Heaney RP, Dowell MS & Hale CA (2003) Calcium absorption varies within the reference range for serum 25-hydroxyvitamin D. J Am Coll Nutr 22, 142146.
62.Outila TA, Kakkainen MU & Lamberg-Allardt CJ (2001) Vitamin D status affects serum parathyroid hormone concentrations during winter in female adolescents: associations with forearm bone mineral density. Am J Clin Nutr 74, 206210.
63.Lehtonen-Veromaa MK, Mottonen TT, Nuotio IO, Irjala KMA, Leino AE & Viikari JSA (2002) Vitamin D and attainment of peak bone mass among peripubertal Finnish girls: a 3-y prospective study. Am J Clin Nutr 76, 14461453.
64.Cheng S, Tylavsky F, Kroger H et al. (2003) Association of low 25-hydroxvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early pubertal and prepubertal Finnish girls. Am J Clin Nutr 78, 485492.
65.El-Hajj Fuleihan G & Veith R (2007) Vitamin D insufficiency and musculoskeletal health in children and adolescents. In Nutritional Aspects of Osteoporosis 2006, pp. 91108 [Burckhard B, Heaney RP and Dawson-Hughes B editors]. Oxford: Elsevier.
66.El-Hajj Fuleihan G, Nabulsi M, Choucair M, Salamoun M, Hajj Shahine C, Kizirian A & Tannous R (2001) Hypovitaminosis D in healthy schoolchildren. Pediatrics 107, E53.
67.Viljakainen HT, Natri AM, Karkkainen M, Huttunen MM, Palssa A, Jakobsen J, Cashman KD, Molgaard C & Lamberg-Allardt C (2006) A positive dose-response effect of vitamin D supplementation on site-specific bone mineral augmentation in adolescent girls: a double-blinded randomized placebo-controlled 1-year intervention. J Bone Miner Res 21, 836844.
68.Chapuy MC, Arlot ME, Duboeuf F, Brun J, Crouzet B, Arnaud S, Delmas PD & Meunier PJ (1992) Vitamin D and calcium to prevent hip fractures in elderly women. N Engl J Med 327, 16371642.
69.Dawson-Hughes B, Harris SS, Krall EA & Dallal GE (1997) Effect of Ca and vitamin D supplementation on bone density in men and women 65 years of age or older. N Engl J Med 337, 670676.
70.Larsen ER, Mosekilde L & Foldspang A (2004) Vitamin D and calcium supplementation prevents osteoporotic fractures in elderly community dwelling residents: a pragmatic population-based 3-year intervention study. J Bone Miner Res 19, 370378.
71.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. J Bone Miner Res 17, 709715.
72.Bischoff-Ferrari HA, Willett WC, Wong JB, Giovannucci E, Dietrich T & Dawson-Hughes B (2005) Fracture prevention with vitamin D supplementation: a meta-analysis of randomised controlled trials. JAMA 293, 22572264.
73.Smith H, Anderson F, Raphael H, Maslin P, Crozier S & Cooper C (2007) Effect of annual intramuscular vitamin D on fracture risk in elderly men and women – a population-based, randomized, double-blind, placebo-controlled trial. Rheumatology 46, 18521857.
74.Trivedi DP, Doll R & Khaw KT (2003) Effect of four monthly oral vitamin D3 supplementation on fractures and mortality in men and women living in the community: a randomised double blind controlled trial. Br Med J 326, 469474.
75.Porthouse J, Cockrayne S, King C et al. (2005) Randomised controlled trial of calcium supplementation with cholecalciferol (vitamin D3) for prevention of fractures in primary care. Br Med J 330, 10031006.
76.Grant AM, Avenell A, Campbell MK et al. (2005) Oral vitamin D3 and calcium for the secondary prevention of low-trauma fractures in elderly people (Randomised Evaluation of Calcium Or vitamin D, RECORD): a randomised placebo-controlled trial. Lancet 365, 16211628.
77.Sambrook P (2005) Vitamin D and fractures: quo vadis? Lancet 365, 15991600.
78.Avenell A, Gillespie W, Gillespie L & O'Connell D (2005) Vitamin D and vitamin D analogues for preventing fractures associated with involutional and postmenopausal osteoporosis. The Cochrane Database of Systematic Reviews 2005, issue 3, CD000227.
79.Tang BM, Eslick GD, Nowson C, Smith C & Bensoussan A (2007) Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis. Lancet 370, 657666.
80.Dam H (1935) The antihaemorrhagic factor of the chick. Biochem J 29, 12731285.
81.Bolton-Smith C (1993) Vitamin K. In Human Nutrition and Dietetics, pp. 208238 [James WPT and Garrow JS editors]. Edinburgh: Churchill Livingstone.
82.Shearer MJ, Bach A & Kohlmeier M (1996) Chemistry, nutritional sources, tissue distribution and metabolism of vitamin K with special reference to bone health. J Nutr 126, 1181S1186S.
83.Booth S (2003) Dietary vitamin K and bone health. In Nutritional Aspects of Bone Health, pp. 323338 [New SA and Bonjour JP editors]. Cambridge: Royal Society of Chemistry.
84.Szulc P, Chapuy M-C, Meunier PJ & Delmas PD (1996) Serum undercarboxylated osteocalcin is a marker of the risk of hip fracture: a three year follow up study. Bone 18, 487488.
85.Binkley NC, Krueger DC, Engelke JA, Foley AL & Suttie JW (2000) Vitamin K supplementation reduces serum concentrations of under-gamma carboxylated osteocalcin in healthy young and elderly adults. Am J Clin Nutr 72, 15231528.
86.Weber P (2001) Vitamin K and bone health. Nutrition 17, 880887.
87.Bolton-Smith C, McMurdo ME, Paterson CR, Mole PA, Harvey JM, Fenton ST, Prynne CJ, Mishra GD & Shearer MJ (2007). A two-year randomized controlled trial of vitamin K1 (phylloquinone) and vitamin D3 plus calcium on the bone health of older women. J Bone Miner Res 22, 509519.
88.Braam LA, Knapen MH, Geusens P, Brouns F, Hamulyák K, Gerichhausen MJ & Vermeer C (2003) Vitamin K1 supplementation retards bone loss in postmenopausal women between 50 and 60 years of age. Calcif Tissue Int 73, 2126.
89.Knapen MHJ, Schurgers LJ & Vermeer C (2007) Vitamin K2 improves hip bone geometry and bone strength indices in postmenopausal women. Osteoporos Int 18, 963972; Epublication 8 February 2007.
90.Cockrayne R, Adamson J, Lanham-New SA, Shearer MJ, Gilbody S & Torgerson DJ (2006) Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trials. Arch Intern Med 166, 12561261.
91.Shearer MJ, Cockrayne R, Adamson J, Lanham-New SA, Gilbody S & Torgerson DJ (2007) Vitamin K and bone health. Arch Intern Med 167, 9495.
92.Jarvinen TLN, Sievanen H, Khan KM, Heinonen A & Kannus P (2008) Shifting the focus in fracture prevention from osteoporosis to falls. Br Med J 336, 124126.
93.Bischoff-Ferrari HA, Dawson-Hughes B, Baron JA et al. (2007) Calcium intake and hip fracture risk in men and women: a meta-analysis of prospective cohort studies and randomized controlled trials. Am J Clin Nutr 86, 17801790.
94.Food Standards Agency (2002) Food Portion Sizes, 3rd ed. London: The Stationery Office.
95.McCance RA & Widdowson EM (2004) The Composition of Foods, 6th ed. Cambridge: Royal Society of Chemistry.
96.Sasaki N, Kusano E, Takahashi H, Ando Y, Yano K, Tsuda E & Asano Y (2005) Vitamin K2 inhibits glucocorticoid-induced bone loss partly by preventing the reduction of osteoprotegerin (OPG). J Bone Miner Metab 23, 4147.
97.Shiraki M, Shiraki Y, Aoki C & Miura M (2000) Vitamin K2 (menatetrenone) effectively prevents fractures and sustains lumbar bone mineral density in osteoporosis. J Bone Miner Res 15, 515522.
98.Iwamoto J, Takeda T & Ichimura S (2001) Effect of menatetrenone on bone mineral density and incidence of vertebral fractures in postmenopausal women with osteoporosis: a comparison of with the effect of etidronate. J Orthop Sci 6, 487492.
99.Ishida Y & Kawai S (2004) Comparative efficacy of hormone replacement therapy, etidronate, calcitonin, alfacalcidol and vitamin K in postmenopausal women with osteoporosis: The Yamaguchi Osteoporosis Prevention Study. Am J Med 117, 549555.
100.Sato Y, Honda Y, Kuno H & Oizumi K (1998) Menatetrenone ameliorates osteopenia in disuse-affected limbs of vitamin D and K-deficient stroke patients. Bone 23, 291296.
101.Sato Y, Honda Y, Asho T, Hosokawa K, Kondo I & Satoh K (2002) Amelioration of osteoporosis by menatetrenone in elderly female Parkinson's disease patients with vitamin D deficiency. Bone 31, 114118.
102.Sato Y, Kanoko T, Satoh K & Iwanmoto J (2005) Menatetrenone and vitamin D2 with calcium supplements prevent nonvertebral fractures in elderly women with Alzheimer's disease. Bone 36, 6168.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Proceedings of the Nutrition Society
  • ISSN: 0029-6651
  • EISSN: 1475-2719
  • URL: /core/journals/proceedings-of-the-nutrition-society
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 175
Total number of PDF views: 758 *
Loading metrics...

Abstract views

Total abstract views: 1221 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 19th January 2018. This data will be updated every 24 hours.