title: Vitamin D threshold to prevent aromatase inhibitor-related bone loss: the B-ABLE prospective cohort study.
abstract: Aromatase inhibitor (AI)-related bone loss is associated with increased fracture rates. Vitamin D might play a role in minimising this effect. We hypothesised that 25-hydroxy-vitamin D concentrations [25(OH)D] after 3 months supplementation might relate to bone loss after 1 year on AI therapy. We conducted a prospective cohort study from January 2006 to December 2011 of a consecutive sample of women initiating AI for early breast cancer who were ineligible for bisphosphonate therapy and stayed on treatment for 1 year (N = 232). Serum 25(OH)D was measured at baseline and 3 months, and lumbar spine (LS) bone mineral density at baseline and 1 year. Subjects were supplemented with daily calcium (1 g) and vitamin D(3) (800 IU) and additional oral 16,000 IU every 2 weeks if baseline 25(OH)D was <30 ng/ml. Linear regression models were fitted to adjust for potential confounders. After 1 year on AI therapy, 232 participants experienced a significant 1.68 % [95 % CI 1.15-2.20 %] bone loss at LS (0.017 g/cm(2) [0.012-0.024], P < 0.0001). Higher 25(OH)D at 3 months protected against LS bone loss (-0.5 % per 10 ng/ml [95 % CI -0.7 to -0.3 %], adjusted P = 0.0001), and those who reached levels ≥40 ng/ml had reduced bone loss by 1.70 % [95 % CI 0.4-3.0 %; adjusted P = 0.005] compared to those with low 25(OH)D levels (<30 ng/ml). We conclude that improved vitamin D status using supplementation is associated with attenuation of AI-associated bone loss. For this population, the current Institute of Medicine target recommendation of 20 ng/ml might be too low to ensure good bone health.
authors.affiliation: URFOA-IMIM, Parc de Salut Mar, Parc de Recerca Biomèdica de Barcelona, C/Dr Aiguader, 88, 2nd Floor, 08003 Barcelona, Spain. dprieto@imim.es
authors.forename: Daniel
authors.initials: D
authors.lastname: Prieto-Alhambra
authors.forename: Sonia
authors.initials: S
authors.lastname: Servitja
authors.forename: M Kassim
authors.initials: MK
authors.lastname: Javaid
authors.forename: Laia
authors.initials: L
authors.lastname: Garrigós
authors.forename: Nigel K
authors.initials: NK
authors.lastname: Arden
authors.forename: Cyrus
authors.initials: C
authors.lastname: Cooper
authors.forename: Joan
authors.initials: J
authors.lastname: Albanell
authors.forename: Ignasi
authors.initials: I
authors.lastname: Tusquets
authors.forename: Adolfo
authors.initials: A
authors.lastname: Diez-Perez
authors.forename: Xavier
authors.initials: X
authors.lastname: Nogues
mesh_terms: D000368:Aged; D047072:Aromatase Inhibitors / Q000009:adverse effects*; D015519:Bone Density / Q000187:drug effects; D001862:Bone Resorption / Q000139:chemically induced* / Q000517:prevention & control*; D015331:Cohort Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood* / Q000592:standards
chemical_list: D047072:Aromatase Inhibitors; D014807:Vitamin D; C104450:25-hydroxyvitamin D