Aspects of fracture risk in elderly women

The main purpose of this thesis was to identify and further specify factors relevant for the assessment of fracture risk. The studies were conducted on two different cohorts of elderly women. The Osteoporosis Prospective Risk Assessment study (OPRA) is a cohort of women followed for over a decade, from the age of 75. The Distal Forearm Fracture study (DFF) is a cross-sectional cohort of postmenopausal women with a distal forearm fracture and age-matched controls, with a mean age of 65.

Even though the mortality among individuals that declined participation in the OPRA study was increased, it appeared that participants were fairly representative in terms of fracture risk in general. In the OPRA cohort, self-reported history of fall corresponded to increased risk of distal forearm and any osteoporosis-related fracture. Decreased gait speed and a failed balance test corresponded to increased hip fracture risk. Current smokers had an increased risk of vertebral and any osteoporosis-related fracture. Smoking cessation reduced the risk of vertebral fracture. Time as a smoker corresponded to increased vertebral fracture risk. However, amount smoked and time from cessation did not affect fracture risk. In the DFF cohort, women with fracture had decreased site-specific volumetric trabecular and cortical BMD, as well as geometric alterations with increased size and decreased cortical thickness. Weak correlations between parathyroid hormone levels and 25-hydroxy vitamin D with cortical and trabecular bone were observed. Out of 161 women with a distal forearm fracture, 13 women (8%) were diagnosed with primary hyperparathyroidism, suggesting a higher prevalence than in the general population.

In summary, external validity in studies on fracture risk may be satisfactory. It appears to be of great importance to consider physical function and smoking habits in elderly women in the fracture risk assessment. In addition, both trabecular and cortical bone reductions as well as geometric alterations of the forearm may be contributing factors in the pathogenesis of a distal forearm fracture. The occurrence of primary hyperparathyroidism appears to be high in women with a distal forearm fracture, suggesting that further evaluation following a low-energy distal forearm fracture might be beneficial.

List of scientific papers

I. Wihlborg A, Åkesson K, Gerdhem P. (2014). External validity of a population-based study on osteoporosis and fracture. Acta Orthopaedica. 85(4):433-437.
https://doi.org/10.3109/17453674.2014.920987

II. Wihlborg A, Englund M, Åkesson K, Gerdhem P. (2015). Fracture predictive ability of physical performance tests and history of falls in elderly women: a 10-year prospective study. Osteoporosis International. 26(8): 2101-2109.
https://doi.org/10.1007/s00198-015-3106-1

III. Thorin M H, Wihlborg A, Åkesson K, Gerdhem P. (2016). Smoking, smoking cessation, and fracture risk in elderly women followed for 10 years. Osteoporosis International. 27(1): 249-255.
https://doi.org/10.1007/s00198-015-3290-z

IV. Wihlborg A, Bergström K, Åkesson K, Bergström I, Gerdhem P. Site-specific volumetric skeletal and muscle changes in women with a forearm fracture at different stages of ageing. [Manuscript]

V. Wihlborg A, Bergström K, Gerdhem P, Bergström I. Parathyroid hormone disturbances in postmenopausal women with distal forearm fracture. [Manuscript]