The influence of vitamin D and osteoporosis on fracture healing

This thesis starts with a comprehensive review of the literature on the role of vitamin D in fracture healing. Followed by three clinical studies on the prevalence of vitamin D deficiency in fracture patients, risk factors and effect of vitamin D status on fracture healing. The second part of this thesis begins with an extensive review on the effect of osteoporosis and its treatment on fracture healing. A retrospective study is performed on the effect of osteoporosis on fracture healing. Also a more fundamental study on osteoporosis is performed, levels of sclerostin are determined in fracture patients with osteoporosis as biomarker. In the appendix of this thesis, two case reports are presented which illustrate the role of vitamin D plays in bone metabolism and fracture healing.Overall, vitamin D plays a role in fracture healing, although the exact mechanismremains not fully elucidated. The influence of vitamin D deficiency on fracturehealing cannot be fully ignored, but the exact degree of influence is not determined yet.Since the high prevalence of vitamin D deficiency found among adult and paediatricfracture patients, clinicians should be aware of vitamin D deficiency and the prevailingadvice regarding vitamin D supplementation, especially in case of delayed fractureunion or fracture non union.Although animal studies show a negative effect of osteoporosis on fracture healing,convincing clinical evidence lack to support this potential association. Since no negativeeffect of anti-osteoporosis medication on fracture healing could be determined inpatients, treatment should not be withheld in case of a fracture.