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Abstract: A large body of epidemiological evidence suggests an inverse relationship between physical activity and risk of fractures. However, it is unclear how this association varies according to the domain of life in which the activity is undertaken. In this analysis of the European Prospective Investigation of Cancer-Norfolk study, we assessed total and domain-specific physical activity using a validated questionnaire (EPAQ2) in 14,903 participants (6514 men, mean age 62year) who also underwent quantitative ultrasound of the heel. After a median follow-up of 7.5years, there were 504 fractures of which 164 were hip fractures. In multivariable linear regression analysis, broadband ultrasound attenuation (BUA) was positively associated with total and leisure-time activities while showing no association with transportation and work activities. Home activities were associated with a lower BUA among younger participants. In multivariable Cox proportional-hazards models, moderate activities at home and in leisure time were associated with lower hip fracture risk among women (hazard ratios [HR] 0.51 and 0.55, p value 0.02 and 0.03, respectively). Among men, leisure-time activities were associated with lower risk of hip fracture (HR=0.58; p for trend<0.001) whereas activities at home were associated with higher risk of any fracture (HR=1.25; p for trend=0.008). Walking for leisure or transport was associated with lower risk of fracture in both men and women. Multivariable fractional polynomial modelling showed a U-shaped association between home activities and fracture risk especially among women. This study suggests that different domains of physical activity may relate differently to fracture risk and these relationships may vary by sex. [ABSTRACT FROM AUTHOR]

Abstract: The role of quantitative ultrasound (QUS) in clinical practice is debatable. An unanswered question is that whether combining QUS and BMD measurements could improve the prediction of fracture risk. We examined this in a sample of men and women in the European Prospective Investigation into Cancer (EPIC)-Norfolk who had both heel QUS and hip DXA between 1995 and 1997 and were followed for any incident fracture up to 2007. From 1455 participants (703 men) aged 65–76 years at baseline, 79 developed a fracture over 10.3±1.4 years of follow-up. Two separate sex-stratified Cox proportional-hazard models were used including clinical risk factors and total hip BMD. Heel broadband ultrasound attenuation (BUA) was also included in the second model. Global measures of model fit, area under ROC curve, and the Hosmer–Lemeshow statistic showed relative superiority of the model including BUA. Using each model, we calculated 10-year absolute risk of fracture for all participants and categorized them in groups of <5%, 5% to <15%, and ≥15%. Comparison of groupings showed a total re-classification of 16.6% of participants after inclusion of BUA with the greatest re-classification (30.7%) among the group with intermediate risk. Adding a QUS measurement to models based on clinical risk factors and BMD improves the predictive power of models and suggests that further attention should be paid to QUS as a clinical tool for fracture risk assessment. [Copyright &y& Elsevier]

Abstract: A sample size of 30 degrees of freedom (df) for bone mineral density (BMD) precision studies may be insufficient for reliably categorizing change. Monte Carlo simulation was used to evaluate the effect of precision study sample size on identifying change in clinical patients. Least significant change (LSC) from 198 spine and 193 total hip scan-pairs was used to categorize change for 1420 patients undergoing BMD monitoring. Relative to this reference change fraction (RCF), LSC limits were identified that gave specified deviations from the RCF (−25% to +25%). Confidence limits (95% and 80%) for these LSC values (5 to 500 df) were estimated using ‘bootstrap’ samplings. A sample size providing 140 df is needed to avoid overdetecting spine change by 5% and 150 df to avoid underdetecting spine change by 5% with 95% confidence limits. A sample size of 30 df resulted in up to a 12.5% overdetection and 10.0% underdetection of spine or hip change based upon 95% confidence limits. In conclusion, assessing the effect of precision study sample size on classifying change in monitored patients is an important element of the precision assessment that is neglected in current recommendations. Sample sizes larger than 30 df are required if low levels of categorization error are to be achieved. [Copyright &y& Elsevier]

Abstract: An estimated one in three adults aged 65 years or older falls each year, making falls a major health concern. Hip fractures are the most serious consequences of falls in elderly people. Identifying the characteristics of falls leading to hip fracture may provide information about high risk individuals, environment, and activities useful for the development of intervention strategies. Little is known, however, about the incidence and characteristics of falls leading to hip fracture in Middle Eastern countries. Therefore, the authors presented data from the Iranian Multicenter Study on Accidental Injuries, a prospective population-based study conducted in 9 provinces of Iran in 2003. All the hospitals serving about 9.5 million people in the study area were prospectively surveyed for any incident injury resulting from accidental events. A total of 2186 patients (1372 male, 814 female) were admitted due to any injurious fall events, where 572 (26.2%) of them suffered a hip fracture. Annual incidence rates of injurious fall events and related hip fractures were 116.3 and 30.4 per 100,000 person-years, respectively. These figures were 237.1 and 93.6 per 100,000 person-years for people over the age of 50 years, respectively. 71% of fall injuries and 76% of hip fractures occurred indoors. Among 450 patients with hip fractures ≥50 years of age, 61.8% arose from a fall from standing height or less. Only 1 in these 450 hip fractures occurred at the time of recreational activity. In multivariate logistic regression analysis, no factor was an independent predictor of hip fractures comparing to other fall-related injuries among younger participants (≥20 and <50 years). For older patients, falls from standing height or loss (odds ratio (OR) = 2.67), falls during walking (OR = 1.71), and falls on stairs (OR = 1.73) were detected as risk factors of hip fracture. Married persons and those falling from a ladder or other elevations were less likely to fracture their hip in this age group. Our data suggest that modification of the factors external to the homes is less likely to prevent more than a small proportion of fall-related hip fractures in Iran. Further studies on this topic have potential applications for developing preventive strategies. [Copyright &y& Elsevier]