Event Abstract Back to Event Associations between vitamin D2 and D3 and cortical bone phenotypes in childhood: a prospective cohort study E Sayers1*, WD Fraser2, DA Lawlor3 and JH Tobias1 1 University of Bristol, Muscloskeletal Research Unit, United Kingdom 2 University of Liverpool, Department of Muscloskeletal Biology, United Kingdom 3 University of Bristol, MRC Centre for Causal Analyses in Translational Epidemiology, United Kingdom Introduction: Severe vitamin D deficiency, which is generally caused by reduced dietary intake and/or sun exposure, may lead to the clinical condition of osteomalacia/rickets as a result of defective skeletal mineralisation. However less is known about the consequences of milder vitamin D deficiency (insufficiency) for bone development in childhood.{BR}Methods: Using 3260 children from the Avon Longitudinal Study of Parents and Children we examined the relationship between plasma levels of 25(OH)D2 and 25(OH)D3 measured at the median age of 9.9 years, and cortical bone geometry as measured at 50% mid tibia using pQCT at a median age of 15.5 years. Analyses, which were by bootstrap linear regression, were adjusted for age, sex, body composition, social economic position and physical activity. 25(OH)D3 was seasonally adjusted. Analyses between 25(OH)D3 and cortical bone outcomes were adjusted for 25(OH)D2 and vice versa.{BR}Results: 25(OH)D2 was positively related to periosteal circumference (PC) [b=0.032 (95%CI: 0.003,0.062) p=0.03], but inversely related to cortical bone mineral density (BMDC) [b=-0.041 (95%CI: -0.073,-0.008) p=0.01] (b ~represents SD change per doubling of vitamin 25(OH)D2 or 25(OH)D3 ). 25(OH)D3 was unrelated to either of these parameters, but was instead positively related to cortical thickness, reflected by an inverse association with endosteal circumference adjusted for PC [b=-0.024 (95%CI: -0.040,-0.008) p=0.004].{BR}Differing associations of 25(OH)D2 and 25(OH)D3 with cortical bone geometry were mirrored by distinct relationships with indices of bone strength: 25(OH)D2 was associated with reduced resistance to buckling, reflected by a positive association with buckling ratio (BR) [b=0.052 (0.008,0.097) p = 0.02]; in contrast, 25(OH)D3 was associated with greater resistance to buckling, shown by a negative association with BR [b=-031 (95%CI: -0.059,-0.004), p = 0.03]. These associations of 25(OH)D2 and 25(OH)D3 with BR differed statistically (p=0.001).{BR}Conclusions: 25(OH)D2 and 25(OH)D3 levels as measured at a median of age 9.9 years had distinct relationships with cortical bone geometry as measured at age 15.5 years, and showed opposing associations with cortical bone strength. Although our results were adjusted for a range of possible confounders, residual confounding could still be responsible, or alternatively our results could reflect distinct biological actions of 25(OH)D2/D3 on cortical bone development. Keywords: Bones, Bone Research Conference: 2011 joint meeting of the Bone Research Society & the British Orthopaedic Research Society, Cambridge, United Kingdom, 27 Jun - 29 Jun, 2011. Presentation Type: Poster Topic: Abstracts Citation: Sayers E, Fraser W, Lawlor D and Tobias J (2011). Associations between vitamin D2 and D3 and cortical bone phenotypes in childhood: a prospective cohort study. Front. Endocrinol. Conference Abstract: 2011 joint meeting of the Bone Research Society & the British Orthopaedic Research Society. doi: 10.3389/conf.fendo.2011.02.00058 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Sep 2011; Published Online: 30 Sep 2011. * Correspondence: Prof. E Sayers, University of Bristol, Muscloskeletal Research Unit, United Kingdom, adrian.sayers@bristol.ac.uk Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers E Sayers WD Fraser DA Lawlor JH Tobias Google E Sayers WD Fraser DA Lawlor JH Tobias Google Scholar E Sayers WD Fraser DA Lawlor JH Tobias PubMed E Sayers WD Fraser DA Lawlor JH Tobias Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.