Disputas – cand.med Marit Osima
Cand.med Marit Osima disputerer for ph.d.-graden i helsevitenskap og vil offentlig forsvare avhandlingen:
“Cortical porosity, medullary adiposity, type 2 diabetes mellitus, serum vitamin D, parathyroid hormone, and nonvertebral fractures”
Kort sammendrag av avhandlingen:
Despite advances in therapies, assessment of fracture risk and diagnosis of bone fragility, few women and men with high fracture risk receive treatment, even after they develop fracture. To be able to recognize and identify subjects who are at risk for fragility fracture, and to target treatment well, it is important to search for risk factors that are associated with, or ideally, predict fracture.
In case-control studies from Tromsø and Melbourne, we studied medullary adiposity, type 2 diabetes mellitus (T2DM), parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D], and explored the role of cortical porosity in the associations between risk factors and nonvertebral fracture.
Fracture cases had higher medullary adiposity and higher cortical porosity of the distal tibia and distal radius. Higher medullary adiposity and cortical porosity were associated with increased odds for nonvertebral fracture. Women with T2DM had lower cortical porosity than those without diabetes, higher glucose was associated with lower bone turnover markers (BTM) and lower cortical porosity of the proximal femur. Higher body mass index (BMI) was associated with lower BTM and thicker cortices of the proximal femur. Women with fracture had lower serum 25(OH)D and higher PTH and BTM than controls, and they had increased cortical porosity, and reduced cortical thickness of the proximal femur. Lower serum 25(OH)D was not associated with cortical parameters or BTM. Higher PTH was associated with increased BTM and higher cortical porosity of the inner transitional zone. Moreover, decreasing 25(OH)D and increasing PTH increased odds for fracture independently of cortical porosity and covariates.
Combining medullary adiposity and cortical porosity may improve identification of women at risk for fracture. Cortical porosity is lower in women with T2DM than in those without. PTH increases intracortical bone turnover, leading to trabecularization of the inner cortical bone.(Avhandlingen er tilgjengelig for utlån hos Seksjon forutdanningstjenester frem til disputasdato)
Hovedveileder førsteamanuensis Åshild Marit Bjørnerem, Institutt for klinisk medisin, Det helsevitenskapelige fakultet, UiT – Norges arktiske universitet
Biveileder professor Erik Fink Eriksen, Institutt for klinisk medisin, Universitet i Oslo
Professor Clifford Rosen, Center for Clinical and Translational Research, Main Medical Center Research Institute, USA – 1.opponent
Research Director & Adjunct Professor Harri Sievänen, The UKK Institute & University of Tampere, Finland – 2. opponent
Førsteamanuensis Ann Kristin Hansen, Institutt for klinisk medisin, Det helsevitenskapelige fakultet, UiT – Norges arktiske universitet – leder av komité
Professor Inger Njølstad, Institutt for samfunnsmedisin, Det helsevitenskapelige fakultet, Universitetet i Tromsø – Norges arktiske universitet
Prøveforelesning over oppgitt emne holdes kl. 10.15, samme sted: "Cost-benefit of prevention of fragility fractures"