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Purpose: The proportion of load transmitted through the lumbar neural arch increases with aging, spinal degeneration, and lordosis, effectively shielding the lumbar vertebral bodies from load. This stress shielding may contribute to bone loss in the vertebral body, leading to increased fracture risk. To test his hypothesis, we performed a study to determine if vertebral body fractures were associated with a higher neural arch/vertebral body volumetric bone mineral density (vBMD) ratio., Methods: Trabecular vBMD was calculated by quantitative CT in the L3 vertebral body and neural arch (pars interarticularis) of 36 women with vertebral compression fractures and 39 controls. Neural arch/vertebral body vBMD ratio was calculated, and its relationship to fracture status was determined using linear regression models adjusted for age and body mass index., Results: Vertebral body trabecular vBMD was lower in fracture cases as compared to controls (mean ± SD, 49.0 ± 36.0 vs. 87.5 ± 36.8 mg/cm(3), respectively; P < 0.001), whereas trabecular vBMD of the neural arch was similar (96.1 ± 57.6 in cases vs. 118.2 ± 57.4 mg/cm(3) in controls; P = 0.182). The neural arch/vertebral body vBMD ratio was significantly greater in the fracture group than in controls (2.31 ± 1.07 vs. 1.44 ± 0.57, respectively; P < 0.001)., Conclusion: These results support the hypothesis that stress shielding is a contributor to vertebral body bone loss and may increase fracture risk. Although further studies are needed, there may be a role for interventions that can shift vertebral loading in the spine to help prevent fracture.

Background and Purpose: Vertebroplasty is an effective treatment for painful compression fractures refractory to conservative management. Because there are limited data regarding the survival characteristics of this patient population, we compared the survival of a treated with an untreated vertebral fracture cohort to determine whether vertebroplasty affects mortality rates., Materials and Methods: The survival of a treated cohort, comprising 524 vertebroplasty recipients with refractory osteoporotic vertebral compression fractures, was compared with a separate historical cohort of 589 subjects with fractures not treated by vertebroplasty who were identified from the Rochester Epidemiology Project. Mortality was compared between cohorts by using Cox proportional hazards models adjusting for age, sex, and Charlson indices of comorbidity. Mortality was also correlated with pre-, peri-, and postprocedural clinical metrics (eg, cement volume use, RDQ score, analog pain scales, frequency of narcotic use, and improvement in mobility) within the treated cohort., Results: Vertebroplasty recipients demonstrated 77% of the survival expected for individuals of similar age, ethnicity, and sex within the US population. Compared with individuals with both symptomatic and asymptomatic untreated vertebral fractures, vertebroplasty recipients retained a 17% greater mortality risk. However, compared with symptomatic untreated vertebral fractures, vertebroplasty recipients had no increased mortality following adjustment for differences in age, sex, and comorbidity (HR, 1.02; 95% CI, 0.82-1.25). In addition, no clinical metrics used to assess the efficacy of vertebroplasty were predictive of survival., Conclusions: Vertebroplasty recipients have mortality rates similar to those of individuals with untreated symptomatic fractures but have worse mortality compared with those with asymptomatic vertebral fractures.

Unlabelled: Application of the WHO fracture prediction algorithm in conjunction with an updated US economic analysis indicates that osteoporosis treatment is cost-effective in patients with fragility fractures or osteoporosis, in older individuals at average risk and in younger persons with additional clinical risk factors for fracture, supporting existing practice recommendations., Introduction: The new WHO fracture prediction algorithm was combined with an updated economic analysis to evaluate existing NOF guidance for osteoporosis prevention and treatment., Methods: The WHO fracture prediction algorithm was calibrated to the US population using national age-, sex- and race-specific death rates and age- and sex-specific hip fracture incidence rates from the largely white population of Olmsted County, MN. Fracture incidence for other races was estimated by ratios to white women and men. The WHO algorithm estimated the probability (%) of a hip fracture (or a major osteoporotic fracture) over 10 years, given specific age, gender, race and clinical profiles. The updated economic model suggested that osteoporosis treatment was cost-effective when the 10-year probability of hip fracture reached 3%., Results: It is cost-effective to treat patients with a fragility fracture and those with osteoporosis by WHO criteria, as well as older individuals at average risk and osteopenic patients with additional risk factors. However, the estimated 10-year fracture probability was lower in men and nonwhite women compared to postmenopausal white women., Conclusions: This analysis generally endorsed existing clinical practice recommendations, but specific treatment decisions must be individualized. An estimate of the patient's 10-year fracture risk should facilitate shared decision-making.

Unlabelled: Vertebral fractures are more strongly associated with specific bone density, structure, and strength parameters than with areal BMD, but all of these variables are correlated., Introduction: It is unclear whether the association of areal BMD (aBMD) with vertebral fracture risk depends on bone density per se, bone macro- or microstructure, overall bone strength, or spine load/bone strength ratios., Materials and Methods: From an age-stratified sample of Rochester, MN, women, we identified 40 with a clinically diagnosed vertebral fracture (confirmed semiquantitatively) caused by moderate trauma (cases; mean age, 78.6 +/- 9.0 yr) and compared them with 40 controls with no osteoporotic fracture (mean age, 70.9 +/- 6.8 yr). Lumbar spine volumetric BMD (vBMD) and geometry were assessed by central QCT, whereas microstructure was evaluated by high-resolution pQCT at the ultradistal radius. Vertebral failure load ( approximately strength) was estimated from voxel-based finite element models, and the factor-of-risk (phi) was determined as the ratio of applied spine loads to failure load., Results: Spine loading (axial compressive force on L3) was similar in vertebral fracture cases and controls (e.g., for 90 degrees forward flexion, 2639 versus 2706 N; age-adjusted p = 0.173). However, fracture cases had inferior values for most bone density and structure variables. Bone strength measures were also reduced, and the factor-of-risk (phi) was 35-37% greater (worse) among women with a vertebral fracture. By age-adjusted logistic regression, relative risks for the strongest fracture predictor in each of the five main variable categories were bone density (total lumbar spine vBMD: OR per SD change, 2.2; 95% CI, 1.1-4.3), bone geometry (vertebral apparent cortical thickness: OR, 2.1; 95% CI, 1.1-4.1), bone microstructure (none significant); bone strength ("cortical" [outer 2 mm] compressive strength: OR, 2.5; 95% CI, 1.3-4.8), and factor-of-risk (phi for 90 degrees forward flexion/overall vertebral compressive strength: OR, 3.2; 95% CI, 1.4-7.5). These variables were correlated with spine aBMD (partial r, -0.32 to 0.75), but each was a stronger predictor of fracture in the logistic regression analyses., Conclusions: The association of aBMD with vertebral fracture risk is explained by its correlation with more specific bone density, structure, and strength parameters. These may allow deeper insights into fracture pathogenesis.

Unlabelled: We used QCT scans obtained in 687 men and women, 21-97 years of age, to estimate the factor of risk for vertebral fracture, Phi(vert), defined as the ratio of spinal loading to vertebral strength. With age, vertebral strength declined and Phi(vert) increased significantly more in women than men. Age- and sex-specific differences in Phi(vert) closely resembled previously reported vertebral fracture incidence., Introduction: Despite the high prevalence of vertebral fractures, little is known about the interaction between spinal loading and vertebral fragility., Materials and Methods: We assessed the ratio of spinal loading to vertebral strength (i.e., the factor of risk, Phi(vert)) in an age- and sex-stratified population-based sample of 700 women and men 21-97 years of age. We measured volumetric BMD (vBMD, mg/cm3) and cross-sectional area (CSA, cm2) of the midvertebral bodies of L1-L3 using QCT and computed vertebral compressive strength from these data using engineering beam theory. A biomechanical model of the trunk was used to estimate compressive forces applied to the L3 vertebral body during standing, bending forward, and bending forward while lifting 10 kg. The factor of risk for fracture, Phi(vert), was computed as the ratio of spinal compressive force to vertebral strength for each activity., Results: Men had a higher vertebral strength at all ages, largely because of their greater CSA. Whereas both sexes exhibited a marked decline in vertebral compressive strength with age (p < 0.001), the decline was greater in women than men (-43% versus -31%, p = 0.008). Compressive forces on L3 were greater in men than women, because of their greater body weight and height. For both sexes, forces during bending and lifting were 8-fold higher than those experienced during upright standing. For all activities, Phi(vert) increased with age, but significantly more so in women than men (p < 0.001). For bending and lifting, Phi(vert-bending) exceeded 1.0 in 30% of women and 12% of men > or =50 years of age, values that are similar to the reported frequency of vertebral fracture., Conclusion: These findings illustrate potential mechanisms underlying vertebral fractures and provide strong rationale for further evaluation of this QCT-based biomechanical approach for assessment of fracture risk.

To put vertebral augmentation (eg, vertebroplasty) into perspective, the etiology and outcomes of vertebral fractures are reviewed. There is considerable debate about which criteria should be used to define a vertebral fracture because there is no consistent relation between symptoms and the degree of vertebral deformity. However, it is the more significant vertebral body deformities that are most closely associated with frequent or severe back pain, and the referrals for vertebral augmentation come mainly from this subset of patients. In addition to their vertebral fractures, these patients typically have osteoporosis or elevated bone turnover, and they are at greatly increased risk of subsequent fractures as a result of falling or, more often, excessive spinal loads from activities of everyday living. Additional risk factors for new vertebral fractures include the number and severity of vertebral deformities at baseline. Moreover, new fractures are most likely in nearby vertebrae, and they occur more frequently in the mid-thoracic or thoracolumbar regions of the spine. Interestingly, these are also the characteristics of the subsequent fractures of contiguous vertebrae considered by some to represent a complication of vertebral augmentation, yet they characterize vertebral fracture risk even in untreated patients. Vertebral fractures are very common among older men and postmenopausal women; they are associated with substantial morbidity and mortality; and they may have a devastating impact on the patient's quality of life. Vertebral augmentation may be able to help many of these patients, although opportunities exist to optimize management strategies with respect to the other factors that influence long-term outcomes in this patient population.

Most fractures occur in postmenopausal women who do not have osteoporosis by bone density criteria (T-score>-2.5). Prevalent vertebral deformity is a strong risk factor for incident fractures independent of bone mineral density, yet the majority of these deformities are clinically unapparent. Spine imaging on a dual-energy densitometer, called vertebral fracture assessment (VFA), can accurately detect these deformities. The purpose of this modeling study was to estimate the lifetime societal costs and health benefits of VFA and confirmatory follow-up radiography to detect prevalent vertebral deformity in osteopenic (T-score -1.5, -2.0, or -2.4) postmenopausal women, followed by anti-resorptive drug therapy for those with one or more deformities. We compared three strategies; no initial drug therapy, 5 yr of initial alendronate therapy, or VFA followed by 5 yr of alendronate therapy in those with one or more vertebral deformities confirmed on radiography (VFA strategy). Results for the base-case analyses showed that the cost per quality adjusted life year (QALY) gained for the VFA strategy relative to no initial drug therapy ranged from 18,000 US dollars (for a 60-yr-old with a femoral neck T-score of -2.4) to 77,000 US dollars (for an 80-yr-old with a T-score of -1.5). VFA with selective confirmatory radiography is cost-effective, assuming a societal willingness to pay per QALY gained of 50,000 US dollars, for postmenopausal women aged 60 to 80 yr with femoral neck T-scores between -2.0 and -2.4, and for women age 60 or 70 yr with a T-score of -1.5. Assuming a societal willingness to pay of 100,000 US dollars per QALY gained, VFA is also cost-effective for women age 80 yr with a T-score of -1.5. These conclusions are robust to reasonable changes in fracture rates, assumed fracture disutility, discount rates, relative risk of fracture attributable to vertebral deformity, alendronate cost, and drug adherence.

Introduction: Approaches for recognizing vertebral fractures remain controversial., Methods: An age-stratified population sample of 512 postmenopausal women was followed with serial radiographs for up to 12 years (4455 person-years)., Results: 112 women experienced a new vertebral fracture (20% reduction in any vertebral height from baseline) within this study period, for an annual age-adjusted (to US white women > or =50 years of age in 2000) incidence of 23 per 1000. Depending on the morphometric definition used, the prevalence of vertebral deformities at baseline ranged from 3 to 90%. A recent method to standardize vertebral heights produced the best agreement with a qualitative clinical reading of the films [kappa (kappa), 0.53]. Almost all of the different baseline definitions predicted future vertebral fractures, but most of the predictive power was attributable to the severe (e.g., 4 SD) deformities included within more generous (e.g., 3 SD) classifications. Whereas the generous definitions were more sensitive, and the restrictive ones more specific, their overall abilities to predict a new vertebral fracture were roughly comparable as evaluated by the c-index (analogous to the area under an ROC curve)., Conclusion: This result suggests that the choice of a morphometry definition depends on the particular application and, in particular, on whether it is more important to maximize sensitivity or specificity.

Prevalent vertebral deformities are predictive of future clinical fractures independent of bone density. We used a Markov model with eight health states to estimate from the societal perspective the cost-effectiveness of using spine radiographs to identify postmenopausal women age 60 or older with one or more vertebral deformities and then treat them with anti-resorptive drug therapy to prevent fractures. We compared three strategies: 5 years of amino-bisphosphonate (alendronate) therapy for all, 5 years of alendronate therapy for only those with prevalent a radiographic vertebral deformity or no initial alendronate treatment. Lifetime direct medical and indirect costs, quality adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) were tracked. For women with one or more prevalent vertebral deformities, the costs per QALY gained ranged from 5,084 dollars (for an 80 year old with a T-score of -2.4) to 61,192 dollars (for a 60 year old with a T-score of -1.0). For women without prevalent vertebral deformity, the costs per QALY gained ranged from 41,897 dollars (for a 60 year old with a T-score of -2.4) to 166,219 dollars (for an 80 year old with a T-score of -1.0). These results were modestly sensitive to reasonable changes in fracture rates, disutility, discount rates and assumptions about the accuracy of spinal radiographs for detecting vertebral deformity. Assuming a societal willingness to pay per QALY gained of 50,000 dollars, the strategy of performing spine radiographs in post-menopausal osteopenic women with T-scores at or below -1.5 and treating those with 1 or more prevalent vertebral deformities is likely to be cost-effective. However, further research on the accuracy of vertebral deformity ascertainment from routine clinical radiographs and on the efficacy of amino-bisphosphonate drugs for reducing the risk of non-vertebral fractures in osteopenic women is needed to define more precisely the subset of osteopenic post-menopausal women in whom use of spinal radiographs is most cost-effective.

Elderly women with the lowest serum estrogen levels are at the greatest risk of bone loss and fractures, but it is controversial whether the ovaries contribute to estrogen production after menopause, and therefore, whether bilateral oophorectomy in postmenopausal women might have adverse skeletal effects. To address this potential problem, we estimated long-term fracture risk among 340 postmenopausal Olmsted County, MN, women who underwent bilateral oophorectomy for a benign ovarian condition in 1950-1987. In over 5632 person-years of follow-up (median, 16 years per subject), 194 women experienced 516 fractures (72% from moderate trauma). Compared with expected rates, there was a significant increase in the risk of any osteoporotic fracture (moderate trauma fractures of the hip, spine, or distal forearm; standardized incidence ratio [SIR], 1.54; 95% CI, 1.29-1.82) but almost as large an increase in fractures at other sites (SIR, 1.35; 95% CI, 1.13-1.59). In multivariate analyses, the independent predictors of overall fracture risk were age, anticonvulsant or anticoagulant use for > or = 6 months, and a history of alcoholism or prior osteoporotic fracture; obesity was protective. Estrogen replacement therapy was associated with a 10% reduction in overall fracture risk (hazard ratio [HR], 0.90; 95% CI, 0.64-1.28) and a 20% reduction in osteoporotic fractures (HR, 0.80; 95% CI, 0.52-1.23), but neither was statistically significant. The increase in fracture risk among women who underwent bilateral oophorectomy after natural menopause is consistent with the hypothesis that androgens produced by the postmenopausal ovary are important for endogenous estrogen production that protects against fractures.

The objective of the study was to estimate the impact of hip and vertebral fractures on quality of life in postmenopausal women using a preference-based health measure that is appropriate for economic evaluations and to investigate correlates of health outcome. Interviews to assess health-related quality of life, which also documented other health conditions and characteristics, were undertaken in women age 50 years and older without osteoporotic fractures compared with women with hip and/or vertebral fracture(s). Health status was characterized by self-reported physical limitations and the mental and physical component summary scores of the SF-36. Quality-adjusted life years (QALYs), which reflect each individual's assessment of her overall health utility, were estimated with time tradeoff values. Regression methods were used to examine QALY correlates (e.g. time since fracture) for each fracture group and to estimate differences in QALYs between fracture and non-fracture subjects after accounting for other patient characteristics. Among 382 women ages 50-96 years, fracture subjects were significantly older, less likely to use hormone replacement therapy and more likely to report physical limitations than non-fracture subjects. On the QALY scale, where 1 represents perfect health and 0 represents death, mean QALY values were 0.82 (95% CI: 0.76, 0.87) among 114 women with one or more vertebral fractures and 0.63 (95% CI: 0.52, 0.74) among 67 with hip fracture compared with 0.91 (95% CI: 0.88, 0.94) among 201 women without fracture. No significant correlates of QALYs were identified among women with vertebral fracture alone. Among hip fracture subjects, time since hip fracture and presence of a vertebral fracture were significant correlates of QALYs. In multiple regression analyses, estimated QALY differences (fracture minus non-fracture subjects) ranged from -0.05 to -0.55 and were equivalent to losses of 20-58 days, 23-65 days and 115-202 days per year for vertebral fracture (p = 0.001), hip fracture (p = 0.009) and hip plus vertebral fracture (p<0.001) subjects, respectively, depending on age. Thus to adequately assess the cost-effectiveness of osteoporosis treatment, the negative impact of vertebral fractures on QALYs, even among women who have survived a hip fracture, must be considered.

Objective: To determine whether the source of preference scores has an impact on the cost-effectiveness of osteoporosis interventions., Methods: Three groups of subjects aged > or =50 years--199 women without fractures and 183 women with osteoporotic fractures-were studied at two major medical centers. Medical history and comorbidity data were obtained from review of medical records. Health status was measured using the Medical Outcomes Study SF-36. Two preference-classification systems (i.e., quality of well-being scores estimated from SF-36 subscales and the Health Utilities Index) were also used. Preferences for current health and for hypothetical health states were assessed using a time tradeoff and implemented with a computer-based utility instrument (U-Titer). Wilcoxon's rank-sum and signed-rank tests were used to compare preferences for current health among women with osteoporotic fractures with 1) directly assessed preferences for osteoporosis health states delineated by outcome descriptions and 2) preference scores obtained from the preference-classification systems. The potential impact of the source of the preference scores was estimated using a Markov state-transition model., Results: The preference scores for hypothetical osteoporosis health states of the non-fracture subjects were approximately 50% lower than those of the women who had actually experienced the health state. Differences of this magnitude would change the estimated cost-effectiveness of a 15-year intervention (which for approximately $280 per year prevents hip fracture about as well as hormone-replacement therapy) from $25,000 per QALY gained when non-fracture subjects' preferences were used to $94,000 per QALY gained when fracture subjects' preferences were used. Preferences estimated using the Health Utilities Index and those directly measured in fracture subjects using the time tradeoff did not differ significantly., Conclusions: The Health Utilities Index preference-classification system may provide an efficient and inexpensive alternative to direct utility assessment in this patient group. However, there are important differences in the valuation of health states by women who have experienced osteoporotic fractures compared with women who have not. Cost-utility analyses based solely on fracture patients' preferences for osteoporotic health states may undervalue prevention.

This population-based study documents an increase in most types of fractures following the occurrence of a clinically recognized vertebral fracture among 820 Rochester, Minnesota, residents. During 4349 person-years of follow-up, 896 new fractures were observed. Relative to incidence rates in the community, there was a 2.8-fold increase in the risk of any fracture, which was greater in men (standardized incidence ratio (SIR), 4.2; 95% CI, 3.2-5.3) than women (SIR, 2.7; 95% CI, 2.4-3.0). The estimated cumulative incidence of any fracture after 10 years was 70%. The greatest increase in risk was for subsequent fractures of the axial skeleton, in particular a 12.6-fold increase (95% CI, 11-14) in additional vertebral fractures. There was a lesser increase in most limb fractures, including a 2.3-fold increase (95% CI, 1.8-2.9) in hip fractures and a 1.6-fold increase (95% CI, 1.01-2.4) in distal forearm fractures. There was a slightly greater association with distal forearm fractures among those whose first vertebral fracture occurred before age 70 years but a similar relationship with hip fractures, including cervical and intertrochanteric hip fractures separately, regardless of age at the initial vertebral fracture. There was also an equivalent increase in subsequent fracture risk whether the initial vertebral fracture was attributed to severe or moderate trauma. These data show that vertebral fractures represent an important risk factor for fractures in general, not just those of the spine and hip.

Among an age-stratified sample of 942 Rochester, MN women, the overall prevalence of any vertebral deformity, as assessed by radiographic morphometry, was 21.3 per 100. The prevalence increased with age and, after adjusting for age, vertebral deformities were independently associated with height, weight, a history of distal forearm or hip fractures, and anticoagulant use. Altogether, 73% of the women with a vertebral deformity and 66% of controls had one or more of the conditions that have been linked with secondary osteoporosis, which in aggregate were associated with an age-adjusted 1.2-fold (95% CI 0.8-1.7) increase in risk that was not statistically significant. The prevalence of severe vertebral deformities was 11.7 per 100 women and the prevalence of very severe deformities was 5.7 per 100. There was a stronger relationship of age and most other risk factors with severe vertebral deformities than with isolated mild deformities, suggesting that a subset of mild deformities may not represent actual vertebral fractures. The metabolic disorders linked with secondary osteoporosis were associated with little increase in the risk of severe vertebral deformities, taken together, or of mild deformities. However, in aggregate these conditions were associated with a 2.3-fold increase (95% 1.1-4.8) in very severe vertebral deformities, which points to a role for rapid cancellous bone loss among women with the worst spinal osteoporosis.

Based on a presumption that the morphometric approach to vertebral fracture assessment is beset by false positive deformities, it has been suggested that more stringent criteria should be used to asses vertebral fracture outcomes in clinical trials of osteoporosis therapies. We applied a variety of criteria in the reanalysis of a randomized trial of sodium fluoride therapy for women with established osteoporosis. Although progressively more severe criteria reduced the cumulative incidence of a new vertebral fracture in both those receiving a placebo and the fluoride-treated patients, differences between the two groups were not magnified and none of the suggested approaches produced a statistically significant result. These findings indicate that the false positive rate associated with morphometric assessment of vertebral fractures is not so great as supposed from theoretical considerations that assume independence among the measurements. Our findings also provide some reassurance that differences in the criteria used to define a vertebral fracture are not the controlling influence in the likelihood that a particular clinical trial will find a result favoring one treatment over another.

The conventional belief is that osteopenia is the major cause of vertebral fractures and that drug therapy must induce a substantial increase in vertebral bone mineral density (BMD) before the vertebral fracture rate (VFR) is decreased. We hypothesized that the increased bone turnover in osteoporosis also is a major cause of vertebral fractures because of its adverse effects on the microarchitecture of the vertebrae and, thus, that normalization of bone turnover by antiresorptive drug therapy will decrease VFR substantially. This hypothesis is supported by our reanalysis of data from previous clinical trials with fluoride and with estrogen therapy in postmenopausal osteoporotic women. As evident from computer-generated three-dimensional graphic plots of data from osteoporotic women treated with placebo, VFR increased as bone turnover increased or as vertebral BMD decreased. Estrogen therapy decreased the bone turnover rate to normal and eliminated the relationship between VFR and bone turnover, whereas the inverse relationship with vertebral BMD persisted. In osteoporotic women treated with fluoride, VFR decreased as vertebral BMD increased, provided that patients with high (toxic) serum fluoride levels were not included in the comparison. Over the range of values in the data set, increased vertebral BMD and decreased bone turnover had approximately equal effects in decreasing VFR. Thus, both formation-stimulating and resorption-inhibiting drugs can substantially decrease VFR but do so by different mechanisms.

Background: Although vertebral fractures are very common among elderly Caucasian women, no studies have compared the prevalence to that among Asian populations. Any observed differences in prevalence might lead to the identification of important environmental and/or genetic factors. We therefore compared the prevalence of vertebral fractures among US Caucasians to native Japanese and Japanese immigrants in Hawaii using a standardized approach., Methods: Spinal radiographs of women aged > 50 years were obtained from native Japanese in Hiroshima, Japanese-Americans in Hawaii, and North American Caucasians in Minnesota between 1982 and 1991. Fractures were defined as vertebral heights > 3 standard deviations (SD) below the vertebra-specific mean., Results: Compared to Japanese-Americans, odds ratios (OR) and 95% confidence intervals (CI) for prevalent vertebral fractures were 1.8 (95% CI: 1.3-2.5) for native Japanese women and 1.5 (95% CI: 1.1-2.1) for Minnesota Caucasians. The OR tended to be higher when comparing the prevalence of two or more fractures per person: OR = 3.2 (95% CI: 2.0-5.3) for native Japanese and OR = 1.9 (95% CI: 1.2-3.2) for Minnesota Caucasians. Similar results were observed for native Japanese using a fracture definition of > or = 4 SD below the mean, but the OR for Caucasians was reduced to 1.2 (95% CI: 0.6-2.3)., Conclusion: The observation that, among these three populations, hip fracture incidence is lowest but spine fracture prevalence is greatest among native Japanese suggests that different risk factors may be responsible.

Objective: To assess the risk of fractures among patients with ankylosing spondylitis (AS)., Methods: A population based cohort study compared fracture incidence in an inception cohort of 158 Rochester, Minnesota residents newly diagnosed with AS between 1935 and 1989 with expected rates from the same community., Results: In 2,398 person-years of observation, there was no increase in the risk of limb fractures, but there was a pronounced increase in the risk of thoracolumbar compression fractures (standardized morbidity ratio = 7.6; 95% CI, 4.3-12.6) among those with AS., Conclusion: These data point to the importance of measures aimed at maintaining axial skeletal status in patients with AS.

In a population-based retrospective cohort study, Rochester women aged 35-69 years who were first diagnosed with one or more vertebral fractures in 1950-1979 were followed for the development of a subsequent hip fracture. The 336 women with no history of hip fracture at the time of their vertebral fracture experienced 52 proximal femur fractures in 4788 person-years of follow-up. The standardized morbidity ratio (SMR) of observed to expected hip fractures was 1.8 (95% CI, 1.3-2.4) and was higher for intertrochanteric than cervical femoral fractures (SMR, 2.3 versus 1.3; P = 0.07). Hip fracture risk among women with symptomatic vertebral fractures was slightly less than in those with asymptomatic vertebral fractures (SMR, 1.8 versus 2.3; not significant), and younger women had no higher risk of a subsequent hip fracture than women who were > or = 60 years of age at the time of their vertebral fracture (SMR, 1.4 versus 1.8; not significant). Alternative explanations are possible, but these data are consistent with heterogeneity in the pathogenesis of different osteoporotic fractures.

There is a need to identify vertebral fractures from radiographs taken at a single point in time, but considerable controversy surrounds the methods to be used. We extended a data set to comprise baseline radiographs of the thoracic and lumbar spine on an age-stratified random sample of 762 Rochester, Minnesota, women and used revised methods to define vertebral deformities morphometrically. Changes in the method of measuring vertebral heights, changes in the source of normal values for vertebral measurements and changes in the criteria for assessing vertebral deformity had little impact on estimated prevalence and incidence in this population. The prevalence of any vertebral deformity was estimated at 25.3 per 100 Rochester women aged 50 years and over (95% CI, 22.3-28.2), while the incidence of a new deformity in this group was estimated at 17.8 per 1000 person-years (95% CI, 16.0-19.7). Projected nationally, these data suggest that over 500,000 white women in the United States develop vertebral deformities for the first time each year and that over 7 million white women aged 50 years and over might be affected at any given time. These estimates are limited by the absence of a reliable 'gold standard' with which to determine false positive and false negative rates associated with this or any other morphometric method. Information on the health consequences of vertebral deformities of various sorts would be most helpful in choosing between alternative approaches to defining them.

Whereas fractures related to osteoporosis have become a pressing public health concern, relatively few epidemiologic studies have focused on vertebral fractures. To shed further light on the occurrence of this injury, we collected data from the Health Care Financing Administration on 151,986 discharges listing a diagnosis of vertebral fracture over a 4-year period. After adjusting for age, white women experienced the highest rates of discharge, at 17.1 per 10,000 per year, followed by white men (9.9 per 10,000), black women (3.7 per 10,000), and black men (2.5 per 10,000). Among white women, discharge rates rose exponentially from 5.3 discharges per 10,000 population at age 65 to nearly 47.8 per 10,000 at age 90. White men, black women, and black men experienced less dramatic age-related increases in discharge rates. The similarity of these patterns to discharge rates for hip fracture suggests that the race-sex differences in vertebral fracture discharge rates may be due to differences in the incidence of vertebral fracture.

Several studies suggest secular increases in hip fracture incidence through this century, but little is known about such trends for vertebral fracture. We have examined changes in the incidence of clinically ascertained vertebral fractures among Rochester, Minnesota residents aged 35-69 years, that were first diagnosed between 1950 and 1989. Our results indicate no overall increase in incidence over the 40-year period. Categorization of fractures according to the level of preceding trauma, however, revealed a significant increase in the incidence of fractures following moderate trauma among women aged 60-69 years. This increase occurred between 1950 and 1964, and leveled off thereafter. Rates for severe trauma fractures among postmenopausal women, and for vertebral fractures from any cause among younger men and women, remained stable. The rise in moderate trauma fractures in postmenopausal women paralleled that for hip fractures in Rochester and began to plateau at around the same time. It might have resulted from increased diagnosis of vertebral fractures, but the increase in hip fracture incidence is inconsistent with this explanation. An increase in the prevalence of osteoporosis, however, might account for the trend in both types of fractures.

Vertebral fractures are the classic hallmark of osteoporosis, yet little is known of their epidemiology. The incidence of clinically diagnosed vertebral fractures was therefore directly assessed in the predominantly white (European descent) population of Rochester, Minnesota. Altogether, 341 Rochester residents were radiologically diagnosed for the first time with one or more vertebral fractures in the 5 year study period, 1985-1989. The overall age- and sex-adjusted incidence rate was 117 per 100,000 person-years (95% CI, 105 to 130). The age-adjusted rate in women (145 per 100,000 person-years) was almost twice that in men (73 per 100,000 person-years). Of all fractures, 47 (14%) followed severe trauma, 282 (83%) followed moderate or no trauma, and 12 (3%) were pathologic. Incidence rates for fractures following moderate trauma were higher in women than in men and rose steeply with age in both genders. In contrast, fractures following severe trauma were more frequent in men, and their incidence increased less with age. These Rochester rates are greater than those previously reported from studies in Britain and Sweden but lower than the incidence rates extrapolated from a prevalence study in this population.

Little is known about the frequency or degree to which vertebral fractures cause pain and physical disability. The purpose of this investigation was to examine the advantages of risk analysis over other statistical techniques (e.g., correlation analysis) for quantifying relationships between vertebral fractures and outcomes such as pain and disability. Subjects who volunteered to participate in studies of osteoporosis were asked about pain and disability. The number and degree of vertebral deformities were assessed from radiographs. Strong associations were observed between the most severe vertebral deformities and the risk of high pain or disability scores, while weaker associations were observed for moderate deformities. There did not appear to be any association between vertebral deformity and risk of moderate levels of pain or disability. Because of the potential for bias in cross-sectional studies such as this, the magnitude of these findings must be considered tentative. We conclude that risk analysis is an appropriate method for quantifying the relationship of vertebral fractures with pain and disability, but that prospective studies are now needed.

Although it is a cardinal feature of involutional osteoporosis, there is often disagreement on what constitutes a vertebral fracture. We measured vertebrae T4-L5 in 52 healthy women to develop a normal range (mean +/- 3 SD) for vertebral shape and used these data to assess the prevalence of vertebral fractures. We classified vertebral fractures by type of deformity (wedge, biconcavity, or compression) and further by the degree of deformity (grades 1 and 2). In 195 postmenopausal women who were an age-stratified random sample of the Rochester population (ages 47-94), 40 (21%) had vertebral fractures (mean, 2 per person). There was a similar number of compression and wedge fractures, and grade 2 fractures were as common as grade 1. In a referral sample of 74 women with suspected osteoporosis, 62 (84%) had vertebral fractures (mean, 3.3 per person). Wedge fractures were most common, and grade 2 fractures were more common than grade 1. The distribution of type and grade of fractures differed between the two patient groups (P less than 0.01). Bone mineral density of the lumbar spine was related to mean fracture grade (r = -0.33, P less than 0.05) and to fracture number (r = -0.57, P less than 0.001) but not to fracture type. We conclude that a comprehensive approach is required in describing vertebral fractures. Using this approach we found distortion in the fracture characteristics of women referred to an osteoporosis clinic compared to women in the community.