Risk factors for clinical fractures among postmenopausal women: a 10-year prospective study.

OBJECTIVE: Only scarce data are available on the long-term absolute risk (AR) of all clinical fractures, taking into account the time when they occurred. Therefore, we assessed during a 10-year follow-up the risk factors associated with the occurrence of any first or second clinical fracture. STUDY DESIGN: This was a population-based study in 10 general practice centres. The sample comprised 2372 postmenopausal women, aged between 50 and 80 years at baseline, who completed a questionnaire about the incidence of radiographically confirmed fractures and fracture risks, analysed by multiple Cox regression. MAIN OUTCOME MEASURE: AR for any clinical fracture. RESULTS: During the 10-year follow-up, 380 women (16%) had a fracture. A first fracture occurred in 267 women (11%). Osteoporosis at the lumbar spine (T-score <-2.5; hazard ratio (HR) 1.8, 95% confidence interval (CI) 1.4-2.3) and age over 60 years (HR1.4, 95% CI 1.1-1.8) were the only risk factors retained in the Cox analysis. The AR in the lowest-risk group was 10%, and it was 23% in the highest-risk group. A second fracture occurred in 113 women during follow-up (5%). The time when a fracture occurred was the only risk factor retained in the Cox analysis. The AR for a second fracture was 41% in the five years after any first fracture before baseline and 25% if the first fracture had occurred earlier (HR 1.8, 95% CI 1.3-2.7). CONCLUSION: In postmenopausal women, over a 10-year follow-up, the AR of a second clinical fracture is highest in the five years after any first clinical fracture. The AR for a first clinical fracture is lower and depends on osteoporosis and age.

Timing and risk factors for clinical fractures among postmenopausal women: a 5-year prospective study.

BACKGROUND: Many risk factors for fractures have been documented, including low bone-mineral density (BMD) and a history of fractures. However, little is known about the short-term absolute risk (AR) of fractures and the timing of clinical fractures. Therefore, we assessed the risk and timing of incident clinical fractures, expressed as 5-year AR, in postmenopausal women. METHODS: In total, 10 general practice centres participated in this population-based prospective study. Five years after a baseline assessment, which included clinical risk factor evaluation and BMD measurement, 759 postmenopausal women aged between 50 and 80 years, were re-examined, including undergoing an evaluation of clinical fractures after menopause. Risk factors for incident fractures at baseline that were significant in univariate analyses were included in a multivariate Cox survival regression analysis. The significant determinants were used to construct algorithms. RESULTS: In the total group, 12.5% (95% confidence interval (CI) 10.1-14.9) of the women experienced a new clinical fracture. A previous clinical fracture after menopause and a low BMD (T-score <-1.0) were retained as significant predictors with significant interaction. Women with a recent previous fracture (during the past 5 years) had an AR of 50.1% (95% CI 42.0-58.1) versus 21.2% (95% CI 20.7-21.6) if the previous fracture had occurred earlier. In women without a fracture history, the AR was 13.8% (95% CI 10.9-16.6) if BMD was low and 7.0% (95% CI 5.5-8.5) if BMD was normal. CONCLUSION: In postmenopausal women, clinical fractures cluster in time. One in two women with a recent clinical fracture had a new clinical fracture within 5 years, regardless of BMD. The 5-year AR for a first clinical fracture was much lower and depended on BMD.

Performance of risk indices for identifying low bone density in postmenopausal women.

OBJECTIVE: To examine the ability of 4 published osteoporosis risk indices to identify women with low bone density. SUBJECTS AND METHODS: Subjects included postmenopausal women 45 years and older consecutively recruited from US clinics, women from general practice centers in The Netherlands (age range, 50-80 years), women in the Rotterdam Study (The Netherlands) 55 years and older, and women aged 55 to 81 years old screened for a clinical trial of alendronate. Bone mineral density (BMD) was measured at the femoral neck or lumbar spine; T scores represent the number of SDs below the mean for young healthy women. One risk index was calculated from age and weight; the other risk indices included up to 4 additional variables obtained by questionnaire. We calculated the sensitivity and specificity for identifying women with BMD T scores of -2.5 or less or -2.0 or less in the US clinic sample and created 3 risk categories, using each of the 4 indices. RESULTS: Data were available for 1102 women from the US clinic sample, 3374 women in the Rotterdam Study, 23,833 women screened for a clinical trial of alendronate, and 4204 women from general practice centers in The Netherlands. Specificity for identifying BMD T scores of -2.5 or less ranged from 37% to 58% (depending on risk index) when sensitivity was approximately 90%. The prevalence of osteoporosis (defined as T scores < or = -2.5) differed widely across the 3 risk categories, ranging from 2% to 4% for the low-risk category to 47% to 61% for the high-risk category in the US clinic sample. For spine BMD in the US clinic sample, the prevalence of T scores of -2.5 or less ranged from 7% (low risk) to 38% (high risk). The large differences in prevalence across risk categories were consistent across the other 3 samples of postmenopausal women in the United States and The Netherlands for all 4 risk indices. CONCLUSIONS: We recommend measuring BMD in women who are classified as having an increased risk of osteoporosis by using any of these risk indices because all 4 indices appear to predict low bone mass equally well. The Osteoporosis Self-assessment Tool index is easiest to calculate and therefore may be most useful in clinical practice.