In old men Scheuermann's disease is not associated with neck or back pain: a Swedish cohort study.

BACKGROUND AND PURPOSE: Scheuermann's disease is characterized by kyphosis and frequently mild back pain. As the level of kyphosis may progress over time, also the level of pain may increase. We evaluated the prevalence of Scheuermann's disease, and their pain, in Swedish elderly men. PATIENTS AND METHODS: The Osteoporotic Fractures in Men (MrOS) Study Sweden (n = 3,014) is a population-based prospective observational study of community-living men aged 69-81 years. At baseline, participants answered a questionnaire including history of neck/back pain during the preceding year and characteristics of any pain (severity, sciatica, and neurological deficits). Lateral thoracic/lumbar spine radiographs were taken of 1,453 men. We included the 1,417 men with readable radiographs. Scheuermann's disease was defined as 3 or more consecutive vertebrae with > 5° wedging with no other explanation for the deformity. RESULTS: 92 of the 1,417 men (6.5%, 95% confidence interval 5.3-7.9) had Scheuermann's disease. 31% of men with and 31% without Scheuermann's disease reported neck pain (P = 0.90) and 51% with and 55% without the disease reported back pain (P = 0.4). Among men with Scheuermann's disease and back pain, none reported severe pain, 57% moderate, and 43% mild, compared with 7%, 50%, and 44% in those without Scheuermann's disease (P = 0.2). In those with Scheuermann's disease 63% reported no sciatica, 15% sciatica without neurological deficits, and 22% sciatica with neurological deficits, compared with 56%, 16%, and 28% in those without the disease (P = 0.6). CONCLUSION: The prevalence of Scheuermann's disease in elderly Swedish men is between 5.3% and 7.9%. The condition seems at this age not to be associated with neck or back pain.

Degenerative inter-vertebral disc disease osteochondrosis intervertebralis in Europe: prevalence, geographic variation and radiological correlates in men and women aged 50 and over.

Objectives: To assess the prevalences across Europe of radiological indices of degenerative inter-vertebral disc disease (DDD); and to quantify their associations with, age, sex, physical anthropometry, areal BMD (aBMD) and change in aBMD with time. Methods: In the population-based European Prospective Osteoporosis Study, 27 age-stratified samples of men and women from across the continent aged 50+ years had standardized lateral radiographs of the lumbar and thoracic spine to evaluate the severity of DDD, using the Kellgren-Lawrence (KL) scale. Measurements of anterior, mid-body and posterior vertebral heights on all assessed vertebrae from T4 to L4 were used to generate indices of end-plate curvature. Results: Images from 10 132 participants (56% female, mean age 63.9 years) passed quality checks. Overall, 47% of men and women had DDD grade 3 or more in the lumbar spine and 36% in both thoracic and lumbar spine. Risk ratios for DDD grades 3 and 4, adjusted for age and anthropometric determinants, varied across a three-fold range between centres, yet prevalences were highly correlated in men and women. DDD was associated with flattened, non-ovoid inter-vertebral disc spaces. KL grade 4 and loss of inter-vertebral disc space were associated with higher spine aBMD. Conclusion: KL grades 3 and 4 are often used clinically to categorize radiological DDD. Highly variable European prevalences of radiologically defined DDD grades 3+ along with the large effects of age may have growing and geographically unequal health and economic impacts as the population ages. These data encourage further studies of potential genetic and environmental causes.

Risk factors for low back pain and sciatica in elderly men-the MrOS Sweden study.

Introduction: The aim of this study was to identify whether factors beyond anatomical abnormalities are associated with low back pain (LBP) and LBP with sciatica (SCI) in older men. Material and Methods: Mister Osteoporosis Sweden includes 3,014 men aged 69­81 years. They answered questionnaires on lifestyle and whether they had experienced LBP and SCI during the preceding 12 months. About 3,007 men answered the back pain (BP) questions, 258 reported BP without specified region. We identified 1,388 with no BP, 1,361 with any LBP (regardless of SCI), 1,074 of those with LBP also indicated if they had experienced LBP (n = 615), LBP+SCI (n = 459). Results: About 49% of those with LBP and 54% of those with LBP+SCI rated their health as poor/very poor (P < 0.001). Men with any LBP to a greater extent than those without BP had poor self-estimated health, depressive symptoms, dizziness, fall tendency, serious comorbidity (diabetes, stroke, coronary heart disease, pulmonary disease and/or cancer) (all P < 0.001), foreign background, were smokers (all P < 0.01), had low physical activity and used walking aids (all P < 0.05). Men with LBP+SCI to a greater extent than those with LBP had lower education, lower self-estimated health, comorbidity, dizziness and used walking aids (all P < 0.001). Conclusions: In older men with LBP and SCI, anatomical abnormalities such as vertebral fractures, metastases, central or lateral spinal stenosis or degenerative conditions may only in part explain prevalent symptoms and disability. Social and lifestyle factors must also be evaluated since they are associated not only with unspecific LBP but also with LBP with SCI.

Dissatisfied patients after total knee arthroplasty: a registry study involving 114 patients with 8-13 years of followup.

BACKGROUND AND PURPOSE: In 2003, an enquiry by the Swedish Knee Arthroplasty Register (SKAR) 2-7 years after total knee arthroplasty (TKA) revealed patients who were dissatisfied with the outcome of their surgery but who had not been revised. 6 years later, we examined the dissatisfied patients in one Swedish county and a matched group of very satisfied patients. PATIENTS AND METHODS: 118 TKAs in 114 patients, all of whom had had their surgery between 1996 and 2001, were examined in 2009-2010. 55 patients (with 58 TKAs) had stated in 2003 that they were dissatisfied with their knees and 59 (with 60 TKAs) had stated that they were very satisfied with their knees. The patients were examined clinically and radiographically, and performed functional tests consisting of the 6-minute walk and chair-stand test. All the patients filled out a visual analog scale (VAS, 0-100 mm) regarding knee pain and also the Hospital and Anxiety and Depression scale (HAD). RESULTS: Mean VAS score for knee pain differed by 30 mm in favor of the very satisfied group (p < 0.001). 23 of the 55 patients in the dissatisfied group and 6 of 59 patients in the very satisfied group suffered from anxiety and/or depression (p = 0.001). Mean range of motion was 11 degrees better in the very satisfied group (p < 0.001). The groups were similar with regard to clinical examination, physical performance testing, and radiography. INTERPRETATION: The patients who reported poor response after TKA continued to be unhappy after 8-13 years, as demonstrated by VAS pain and HAD, despite the absence of a discernible objective reason for revision.

The prevalence of moderate to severe radiographic sacroiliitis and the correlation with health status in elderly Swedish men--the MrOS study.

BACKGROUND: Ankylosing Spondylitis (AS) is a chronic inflammatory disease with onset in young adults, but little is known about the prevalence in older age groups. Furthermore, there is very limited information of health status of elderly patients with AS. Our objective was to estimate the prevalence of moderate to severe radiographic sacroiliitis in elderly men and its impact on health. METHODS: A cross-sectional, population-based survey, that included 1005 men aged 69-81 years old, with the primary aim to study risk factors for osteoporosis (MrOS), was used. X-rays of the pelvis and spine were done for the whole population and then examined by two readers. The prevalences of grade 3-4 sacroiliitis, syndesmophytes and spondylophytes were ascertained. Using a self-administered questionnaire, information was obtained on physical activity (PASE), functional status (IADL items), health related quality of life - QoL (SF-12) and back pain (pain question, Quebec Pain Disability Scale items). RESULTS: Fourteen cases with grade 3-4 sacroiliitis were identified, corresponding to a prevalence of 1.4% (95%CI: 0.7-2.4). Eight of the patients with sacroiliitis had both AS-typical and degenerative changes in the spine, 4 had only degenerative changes and 2 had only AS-related changes. There were no statistically significant differences between those with and without radiographic sacroiliitis regarding demographics, anthropometric measures, smoking status or health status, reflected by measures on physical activity, functional status, health related QoL and back pain. CONCLUSIONS: The prevalence of moderate to severe radiographic sacroiliitis was estimated to be 1.4% among elderly men in Sweden. Self-reported health was only slightly different in those with sacroiliitis, suggesting that the relative impact of AS is modest in this age group.

The COMT val158met polymorphism is associated with prevalent fractures in Swedish men.

INTRODUCTION: Sex steroids are important for growth and maintenance of the skeleton. Catechol-O-methyltransferase (COMT) is an estrogen degrading enzyme. The COMT val158met polymorphism results in a 60-75% difference in enzyme activity between the val (high activity=H) and met (low activity=L) variants. We have previously reported that this polymorphism is associated with bone mineral density (BMD) in young men. The aim of this study was to investigate associations between COMT val158met, BMD and fractures in elderly men. METHODS: Population-based study of Swedish men 75.4, SD 3.2, years of age. Fractures were reported using standardized questionnaires. Fracture and genotype data were available from 2,822 individuals. RESULTS: Total number of individuals with self-reported fracture was 989 (35.0%). Prevalence of >or=1 fracture was 37.2% in COMT(LL), 35.7% in COMT(HL) and 30.4% in COMT(HH) (p<0.05). Early fractures (50 years of age). The OR for fracture of the non-weight bearing skeleton in COMT(HH) compared with COMT(LL+HL) was 0.74 (95% CI 0.59-0.92). No associations between COMT val158met and BMD were found in this cohort of elderly men. CONCLUSIONS: The COMT val158met polymorphism is associated with life time fracture prevalence in elderly Swedish men. This association is mainly driven by early fractures (

Vitamin D receptor 3' haplotypes are unequally expressed in primary human bone cells and associated with increased fracture risk: the MrOS Study in Sweden and Hong Kong.

UNLABELLED: The VDR is a prime candidate gene for osteoporosis. Here, we studied three common VDR haplotypes in relation to bone phenotypes in 5014 participants of the global MrOS Study. We also studied the relative expression of the haplotypes in human bone cells. One haplotype was associated with increased fracture risk and differently expressed in primary human bone cells. INTRODUCTION: Vitamin D plays an essential role in skeletal metabolism by binding to its nuclear steroid receptor, the vitamin D receptor (VDR). The heritability of BMD is well established, and the VDR gene is considered a prime candidate suggested to partially account for genetically controlled BMD variance in the population. MATERIALS AND METHODS: Here, we reconstructed common haplotypes in the VDR 3' untranslated region (UTR) and studied the association to BMD and risk of vertebral fractures in elderly men from Sweden (n = 3014) and Hong Kong (n = 2000), all participants of the global MrOS Study. To assess any functional implications of the VDR polymorphisms, we studied allele-specific expressions of the different VDR 3' UTR haplotypes in the normal chromosomal context of 70 unrelated human trabecular bone samples. This was performed by quantitative genotyping of coding polymorphisms in RNA samples and in corresponding DNA samples isolated from the bone samples. RESULTS: Three major haplotypes were reconstructed and in agreement with the previously well-defined baT, BAt, and bAT haplotypes, herein denoted Hap1, Hap2, and Hap3. The Hap1 haplotype was independently associated with increased risk of vertebral fractures in Swedish men (OR, 1.655; 95% CI, 1.146-2.391; p < 0.01) and with lower lumbar spine BMD in elderly men from Sweden (p < 0.01) and Hong Kong (p < 0.05). The VDR gene was also shown to exhibit a 3' UTR haplotype dependent allelic imbalance, indicating that the VDR Hap1 allele was overexpressed in human trabecular bone samples. CONCLUSIONS: The results indicate that the relatively overexpressed VDR Hap1 haplotype could be considered a risk allele for osteoporosis regardless of ethnicity.

Nonoperatively treated burst fractures of the thoracic and lumbar spine in adults: a 23- to 41-year follow-up.

BACKGROUND CONTEXT: Several studies report a favorable short-term outcome after nonoperatively treated two-column thoracic or lumbar burst fractures in patients without neurological deficits. Few reports have described the long-term clinical and radiological outcome after these fractures, and none have, to our knowledge, specifically evaluated the long-term outcome of the discs adjacent to the fractured vertebra, often damaged at injury and possibly at an increased risk of height reduction and degeneration with subsequent chronic back pain. PURPOSE: To evaluate the long-term clinical and radiological outcome after nonoperatively treated thoracic or lumbar burst fractures in adults, with special attention to posttraumatic radiological disc height reduction. STUDY DESIGN: Case series. PATIENT SAMPLE: Sixteen men with a mean age of 31 years (range, 19-44) and 11 women with a mean age of 40 years (range, 23-61) had sustained a thoracic or lumbar burst fracture during the years 1965 to 1973. Four had sustained a burst fracture Denis type A, 18 a Denis type B, 1 a Denis type C, and 4 a Denis type E. Seven of these patients had neurological deficits at injury, all retrospectively classified as Frankel D. OUTCOME MEASURES: The clinical outcome was evaluated subjectively with Oswestry score and questions regarding work capacity and objectively with the Frankel scale. The radiological outcome was evaluated with measurements of local kyphosis over the fractured segment, ratios of anterior and posterior vertebral body heights, adjacent disc heights, pedicle widths, sagittal width of the spinal canal, and lateral and anteroposterior displacement. METHODS: From the radiographical archives of an emergency hospital, all patients with a nonoperatively treated thoracic or lumbar burst fracture during the years 1965 to 1973 were registered. The fracture type, localization, primary treatment, and outcome were evaluated from the old radiographs, referrals, and reports. Twenty-seven individuals were clinically and radiologically evaluated a mean of 27 years (range, 23-41) after the injury. RESULTS: At follow-up, 21 former patients reported no or minimal back pain or disability (Oswestry Score mean 4; range, 0-16), whereas 6 former patients (of whom 3 were classified as Frankel D at baseline) reported moderate or severe disability (Oswestry Score mean 39; range, 26-54). Six former patients were classified as Frankel D, and the rest as Frankel E. Local kyphosis had increased by a mean of 3 degrees (p<.05), whereas the discs adjacent to the fractured vertebrae remained unchanged in height during the follow-up. CONCLUSIONS: Nonoperatively treated burst fractures of the thoracic or lumbar spine in adults with or without minor neurological deficits have a predominantly favorable long-term outcome, and there seems to be no increased risk for subsequent disc height reduction in the adjacent discs.

Free testosterone is an independent predictor of BMD and prevalent fractures in elderly men: MrOS Sweden.

UNLABELLED: The role of androgens for bone health in elderly men is unclear. We show that free testosterone within the normal range is a predictor of BMD at predominantly cortical bone sites and of previous osteoporosis-related fractures in elderly Swedish men. INTRODUCTION: Osteoporosis-related fractures constitute a major health concern not only in women but also in men. Previous studies have clearly shown that serum levels of estradiol are associated with BMD, whereas more conflicting data have been presented regarding the predictive value of testosterone (T) for bone health in elderly men. The aim of this study was to investigate if serum levels of T are associated with BMD and/or prevalent fractures in a large cohort of elderly men. MATERIALS AND METHODS: In the Swedish part of the MrOS study (n = 2908; average age, 75.4 years), bone parameters were measured using DXA, and prevalent fractures were recorded using standardized questionnaires and by vertebral X-ray analyses. Serum levels of total T, total estradiol (E2), and sex hormone-binding globulin (SHBG) were measured by radioimmunoassay, and free T (FT) and free E2 (FE2) were derived from the mass action equations. Height, weight, age, physical activity, smoking habits, and calcium intake were included together with FT and FE2 in regression models for BMD. RESULTS: FT was an independent positive predictor of BMD in total body, total hip, femur trochanter, and arm but not in the lumbar spine. The highest independent predictive value of FT was found in the arm and the hip (with a relatively high content of cortical bone). FE2 was an independent predictor of BMD at all bone sites studied, and the highest predictive value was seen for lumbar spine (with relatively high content of trabecular bone) BMD. FT but not FE2 was a positive predictor of total body bone area and BMC. FT levels below the median were independent predictors of prevalent osteoporosis-related fractures (OR, 1.56; 95% CI, 1.14-2.14; p < 0.01) and X-ray-verified vertebral fractures (OR, 2.00; 95% CI, 1.34-2.86; p < 0.001). The predictive value of FT for prevalent fractures was not affected by adjustment for BMD. CONCLUSIONS: These findings show that variation of FT within the normal range is an independent but modest predictor of BMD at predominantly cortical bone sites and of previous osteoporosis-related fractures in elderly men. Our data indicate that not only estrogens but also androgens are of importance for bone health in elderly men. Longitudinal studies investigating the predictive value of T for fracture risk in elderly men are required.

Characteristics of Prevalent Vertebral Fractures Predict New Fractures in Elderly Men.

BACKGROUND: Studies have shown that specific characteristics of prevalent vertebral fractures are associated with a markedly low bone mineral density. This study evaluates if these characteristics also predict subsequent fractures. METHODS: MrOS (Mister Osteoporosis) Sweden is a population-based, prospective observational study that includes 3014 community-living men who are sixty-nine to eighty-one years of age. At baseline, 1453 men underwent lateral thoracic and lumbar spine radiography; radiographs of 1427 men were readable. A radiologist identified and characterized prevalent vertebral fractures. Incident fractures during the next five and ten years were objectively registered with use of radiographs. The annual fracture incidence and relative risk of sustaining new fractures were assessed for men with and without baseline prevalent vertebral fracture. Data are presented as the mean and the 95% confidence interval. RESULTS: There were 215 men (15.1%) with at least one prevalent vertebral fracture. During the five-year follow-up, these men had a relative risk of 3.3 (95% confidence interval, 2.6 to 4.3) of sustaining new fractures. The relative risk of sustaining any fracture was especially high in men with two or more prevalent vertebral fractures at 5.5 (95% confidence interval, 3.7 to 7.8), in men with different types of prevalent vertebral fractures at 5.7 (95% confidence interval, 3.6 to 8.5), in men with prevalent fractures in both the thoracic and lumbar regions at 6.4 (95% confidence interval, 4.5 to 8.8), and in men with prevalent fractures with a degree of vertebral body compression in the three worst quartiles, with the relative risk for the worst quartile at 4.0 (95% confidence interval, 2.6 to 5.9). CONCLUSIONS: Older men with a prevalent vertebral fracture have three times increased risk of sustaining new fractures compared with men without a vertebral fracture. Older men with two or more prevalent vertebral fractures, different types of fractures (wedge, biconcave, and/or crush), fractures in both the thoracic and lumbar regions, and a degree of vertebral body compression in the three worst quartiles are at an especially high risk of sustaining new fractures. Older men with prevalent vertebral fractures should be considered for fracture-prevention efforts.

High Serum SHBG Predicts Incident Vertebral Fractures in Elderly Men.

Previous prospective cohort studies have shown that serum levels of sex steroids and sex hormone-binding globulin (SHBG) associate with nonvertebral fracture risk in men. The predictive value of sex hormones and SHBG for vertebral fracture risk specifically is, however, less studied. Elderly men (aged ≥ 65 years) from Sweden and Hong Kong participating in the Osteoporotic Fractures in Men (MrOS) study had baseline estradiol and testosterone analyzed by gas chromatography-mass spectrometry (GC-MS) and SHBG by immunoradiometric assay (IRMA). Incident clinical vertebral fractures (n = 242 cases) were evaluated in 4324 men during an average follow-up of 9.1 years. In a subsample of these men (n = 2256), spine X-rays were obtained at baseline and after an average follow-up of 4.3 years to identify incident radiographic vertebral fractures (n = 157 cases). The likelihood of incident clinical and radiographic vertebral fractures was estimated by Cox proportional hazards models and logistic regression models, respectively. Neither serum estradiol (hazard ratio [HR] per SD increase = 0.93, 95% confidence interval [CI] 0.80-1.08) nor testosterone (1.05, 0.91-1.21) predicted incident clinical vertebral fractures in age-adjusted models in the combined data set. High serum SHBG, however, associated with increased clinical vertebral fracture risk (1.24, 1.12-1.37). This association remained significant after further adjustment for FRAX with or without bone mineral density (BMD). SHBG also associated with increased incident radiographic vertebral fracture risk (combined data set; odds ratio [OR] per SD increase = 1.23, 95% CI 1.05-1.44). This association remained significant after adjustment for FRAX with or without BMD. In conclusion, high SHBG predicts incident clinical and radiographic vertebral fractures in elderly men and adds moderate information beyond FRAX with BMD for vertebral fracture risk prediction.

Low clinical relevance of a prevalent vertebral fracture in elderly men--the MrOs Sweden study.

BACKGROUND CONTEXT: The epidemiology, the fracture pattern, and the clinical relevance of prevalent vertebral fractures in old men are debated wherefore we set out to clarify these issues. METHODS: Mister Osteoporosis (MrOs) Sweden is a population-based cohort of community-living men aged 69-81 years that includes 3,014 men. Out of these, 1,453 men underwent a lateral radiograph of the thoracic and lumbar spine of which 1,427 were readable and classified by a radiologist, that is the sample size in this study. The men also answered a questionnaire evaluating back pain and limitation in activities of daily living (ADLs) because of back pain during the preceding 12 months in addition with fracture history and life style. RESULTS: Fifteen percentage of the men had at least one prevalent vertebral fracture, but only 1/10th of these were aware of their fracture. Among the men with a fracture, 58% had one, 21% two, 9% three, and 11% four or more fractures. In men with only one fracture, 70% of the fractures were located in the thoracic and 30% in the lumbar spine, 85% had a wedge, 13% a biconcave, and 2% a crush-type configuration; one-quarter had a maximum vertebral body compression degree of less than 24% and one-quarter of more than 38%. Among the men with one or several vertebral fracture, 57% reported back pain compared with 55% in those without a fracture (p=.53). Most ADL functions were similar in the men with or without a prevalent vertebral fracture. In the men with one fracture, there was no difference in the occurrence of back pain depending on the fractured region (p=.49), type of the fracture (p=.77), or degree of compression (p=.85). In men with one or several fractures, there were no significant differences in the presence of back pain in any ages (p=.08), nor there were differences in presence of back pain regarding type (p=.08) or number of fractures (p=.21). CONCLUSIONS: A prevalent vertebral fracture is common in old men but has low clinical relevance. There does not seem to be a specific fracture pattern that predisposes for back pain.

Smoking predicts incident fractures in elderly men: Mr OS Sweden.

The aim of this study was to investigate the association between smoking and bone mineral density (BMD) and radiographically verified prevalent vertebral fractures and incident fractures in elderly men. At baseline 3003 men aged 69 to 80 years of age from the Swedish Mr Os Study completed a standard questionnaire concerning smoking habits and had BMD of the hip and spine measured using dual-energy X-ray absorptiometry (DXA); 1412 men had an X-ray of the thoracic- and lumbar spine. Radiologic registers were used to confirm reported new fractures after the baseline visit. At baseline, 8.4% were current smokers. Current smokers had a 6.2% lower BMD at the total hip and a 5.4% lower BMD at the lumbar spine (p < .001). Current smoking remained independently inversely associated with BMD at the hip and lumbar spine after adjusting for age, height, weight, calcium intake, physical activity, and centers as covariates. Prevalent vertebral fractures among current smokers were increased in unadjusted analyses [odds ratio (OR) = 1.90, 95% confidence interval (CI) 1.26-2.87] and after adjustment for lumbar BMD (OR = 1.67, 95% CI 1.09-2.55). Smokers had a high risk for two or more prevalent vertebral fractures (OR = 3.18, 95% CI 1.88-5.36). During the average follow-up of 3.3 years, 209 men sustained an X-ray-verified fracture. Incident fracture risk among smokers was calculated with Cox proportional hazard models. Current smokers had an increased risk of all new fractures [hazard ratio (HR) = 1.76, 95% CI 1.19-2.61]; nonvertebral osteoporotic fractures, defined as humerus, radius, pelvis, and hip fractures (HR = 2.14, 95% CI 1.18-3.88); clinical and X-ray-verified vertebral fractures (HR = 2.53, 95% CI 1.37-4.65); and hip fractures (HR = 3.16, 95% CI 1.44-6.95). After adjustment for BMD, including other covariates, no significant association between smoking and incident fractures was found. Current tobacco smoking in elderly men is associated with low BMD, prevalent vertebral fractures, and incident fractures, especially vertebral and hip fractures.

Non-participants differ from participants as regards risk factors for vertebral deformities: a source of misinterpretation in the European Vertebral Osteoporosis Study.

Interpretation of data in epidemiological cohort studies may be confounded if differences exist between non-participants and participants. In the Malmö part of the European Vertebral Osteoporosis Study (EVOS), which was designed to evaluate the prevalence of vertebral deformity in 50-80-year-old persons, we compared 74 men and 95 women who had been invited, but declined to participate with age- and gender-matched participants as regards alcohol abuse, previous fractures and subsequent mortality, factors known to affect the prevalence of vertebral deformity. We found more men with alcohol abuse, more men with a previous fragility fracture and a tendency to more men with a previous clinical vertebral fracture among the non-participants than in the male participants. In contrast, there were fewer female non-participants than female participants with a previous clinical vertebral fracture. The mortality rate during the decade after the baseline examination was higher among both male and female non-participants. The "true" prevalence of vertebral deformity in the whole male population at risk in Malmö seems to be underestimated in the EVOS study. In women, it is more difficult to estimate the combined result of the confounding factors. Conclusions based on the EVOS participants may not be applicable to the whole population at risk.