Leisure time physical activity and risk of non-vertebral fracture in men and women aged 55 years and older : the Tromso Study

Our aim was to examine associations between leisure time physical activity and risk of non-vertebral fractures in men and women aged ≥55 years, with focus on the anatomical fracture location. Self-reported physical activity was registered in 3,450 men and 4,072 women aged 55–97 years at baseline in the Tromsø Study, Norway, in 1994–1995. Non-vertebral fractures were registered through December 31, 2009. During 75,546 person-years at risk, 1,693 non-vertebral fractures were identified. Risk of any non-vertebral fracture decreased with increasing physical activity level in men (P trend = 0.006) and non-significantly in women (P trend = 0.15), after adjustment for age, body mass index, height, smoking, and previous fracture. The reduced fracture risk was due to a reduced risk in the weight-bearing skeleton, particular at the hip, whereas risk of fracture in the non-weight-bearing skeleton was not related to physical activity. At weight-bearing sites, an inverse relationship between physical activity and fracture risk was present in both sexes (P trend ≤ 0.013). Compared with sedentary subjects, the most active men and women had respectively 37% (HR = 0.63, 95% CI: 0.45, 0.88) and 23% (HR = 0.77, 95% CI: 0.62, 0.95) reduced fracture risk in the weight-bearing skeleton. Physical activity is associated with reduced fracture risk at weight-bearing sites, with no associations at non-weight-bearing sites, in both sexes. Habitual physical activity is an important amendable approach to prevent hip fracture

External Validation of the Garvan Nomograms for Predicting Absolute Fracture Risk: The Tromsø Study

BACKGROUND: Absolute risk estimation is a preferred approach for assessing fracture risk and treatment decision making. This study aimed to evaluate and validate the predictive performance of the Garvan Fracture Risk Calculator in a Norwegian cohort. METHODS: The analysis included 1637 women and 1355 aged 60+ years from the Tromsø study. All incident fragility fractures between 2001 and 2009 were registered. The predicted probabilities of non-vertebral osteoporotic and hip fractures were determined using models with and without BMD. The discrimination and calibration of the models were assessed. Reclassification analysis was used to compare the models performance. RESULTS: The incidence of osteoporotic and hip fracture was 31.5 and 8.6 per 1000 population in women, respectively; in men the corresponding incidence was 12.2 and 5.1. The predicted 5-year and 10-year probability of fractures was consistently higher in the fracture group than the non-fracture group for all models. The 10-year predicted probabilities of hip fracture in those with fracture was 2.8 (women) to 3.1 times (men) higher than those without fracture. There was a close agreement between predicted and observed risk in both sexes and up to the fifth quintile. Among those in the highest quintile of risk, the models over-estimated the risk of fracture. Models with BMD performed better than models with body weight in correct classification of risk in individuals with and without fracture. The overall net decrease in reclassification of the model with weight compared to the model with BMD was 10.6% (p = 0.008) in women and 17.2% (p = 0.001) in men for osteoporotic fractures, and 13.3% (p = 0.07) in women and 17.5% (p = 0.09) in men for hip fracture. CONCLUSIONS: The Garvan Fracture Risk Calculator is valid and clinically useful in identifying individuals at high risk of fracture. The models with BMD performed better than those with body weight in fracture risk prediction

Concordance between the predicted and observed risk of non-vertebral osteoporotic fracture (upper panel) and hip fracture (lower panel) in the Tromsø Study cohort, according to the Garvan nomograms.

<p>(A): Quintile cut-offs for the predicted 10-year risk (%) of non-vertebral osteoporotic fracture in women were: 10.8, 15.3, 21.2 and 31.9 for model with BMD (M1); and 12.5, 16.3, 21.3 and 31.5 for model with weight (M2). Corresponding cut-offs in men were 5.3, 8.0, 11.7 and 18.3 for M1; and 5.9, 8.3, 12.1, 17.9 for M2. Quartile cut-offs for the predicted 10-year risk (%) of hip fracture in women were: 1.3, 2.6, 4.9 and 11.2 for M1 and 1.7, 2.9, 5.0 and 11.1 for M2; In men, 0.3, 0.8, 1.6 and 3.9 for M1; and 0.9, 1.5, 2.6 and 4.8 for M2. (B): Quintile cut-offs for the predicted 5-year risk (%) of non-vertebral osteoporotic fracture in women were: 5.2, 7.4, 10.5 and 16.4 for model with BMD (M1); and 6.2, 8.1, 10.8 and 16.5 for model with weight (M2). Corresponding cut-offs in men were 2.8, 4.2, 6.3 and 10.0 for M1; and 3.2, 4.5, 6.6, 10.1 for M2. Quartile cut-offs for the predicted 5-year risk (%) of hip fracture in women were: 0.7, 1.4, 2.7 and 5.8 for M1 and 0.9, 1.6, 2.8 and 6.3 for M2; In men, 0.2, 0.4, 0.8 and 2.1 for M1; and 0.5, 0.8, 1.4 and 2.7 for M2.</p

Baseline characteristics of women and men. The Tromsø Study.

<p>Values are mean (SD), unless otherwise specified.</p><p>* Compared with non-fracture group.</p><p>Baseline characteristics of women and men. The Tromsø Study.</p

Receiver Operating Characteristic (ROC) curves for model with BMD (continuous line) and model with weight (dashed line) for non-vertebral osteoporotic fracture (upper panel) and hip fracture (lower panel) in women and men based on (1A): 5-year predicted risk, and (1B): 10-year predicted risk.

<p>Receiver Operating Characteristic (ROC) curves for model with BMD (continuous line) and model with weight (dashed line) for non-vertebral osteoporotic fracture (upper panel) and hip fracture (lower panel) in women and men based on (1A): 5-year predicted risk, and (1B): 10-year predicted risk.</p