Risk Factor For Osteoporotic Fractures Research Articles

Vitamin D deficiency as a risk factor for osteoporotic fractures

The evidence on the association between vitamin D deficiency and fracture incidence is contradictory. Therefore, the objective of this study was to examine whether low serum 25-hydroxyvitamin D (25(OH)D) levels are associated with osteoporotic fractures. The study was conducted among 1311 community-dwelling older men and women of the Longitudinal Aging Study Amsterdam (LASA), an ongoing multidisciplinary cohort study. Serum 25(OH)D was determined using a competitive protein binding assay. Fractures were assessed during six years of follow-up. The data were analyzed using Cox proportional hazards model. In total, 11.3% of the persons had a serum 25(OH)D below 10 ng/ml, 48.4% had a value below 20 ng/ml, and 82.4% had a value below 30 ng/ml. Furthermore, 115 persons (8.5%) had one or more osteoporotic fractures. Different cut points of serum 25(OH)D were examined with a cut point of 12 ng/ml giving the best discrimination between persons with and without fractures (17.5% of the persons fell below this cut point). The lowest percentage of fractures (5.6%) was found above 30 ng/ml. Because an interaction effect with age was found ( p = 0.04), further analyses were conducted separately for persons aged 65–75 years ( n = 656) and for persons aged 75–89 years ( n = 664) at baseline. After adjustment for age, sex, season of blood collection, body mass index, number of chronic diseases, serum creatinine, cognition, smoking and alcohol use, serum 25(OH)D below or equal to 12 ng/ml was associated with an increased fracture risk in the youngest age group (HR = 3.1; 95% CI: 1.4–6.9), but not in the oldest age group (HR = 1.3; 95% CI: 0.7–2.2). For commonly used cut points of serum 25(OH)D (< 10 ng/ml, 10–19.9 ng/ml, 20–29.9 ng/ml, ≥ 30 ng/ml), no statistically significant associations were found after adjustment for confounding. Serum 25(OH)D levels below or equal to 12 ng/ml were associated with an increased fracture risk in persons aged 65–75 years. The relatively low cut point of serum 25(OH)D in our population is possibly caused by high calcium intake in the Netherlands.

Osteoporosis in Patients With Diabetes Mellitus

Demographic trends with longer life expectancy and a lifestyle characterized by low physical activity and high-energy food intake contribute to an increasing incidence of diabetes mellitus and osteoporosis. Diabetes mellitus is a risk factor for osteoporotic fractures. Patients with recent onset of type 1 diabetes mellitus may have impaired bone formation because of the absence of the anabolic effects of insulin and amylin, whereas in long-standing type 1 diabetes mellitus, vascular complications may account for low bone mass and increased fracture risk. Patients with type 2 diabetes mellitus display an increased fracture risk despite a higher BMD, which is mainly attributable to the increased risk of falling. Strategies to improve BMD and to prevent osteoporotic fractures in patients with type 1 diabetes mellitus may include optimal glycemic control and aggressive prevention and treatment of vascular complications. Patients with type 2 diabetes mellitus may additionally benefit from early visual assessment, regular exercise to improve muscle strength and balance, and specific measures for preventing falls.

B vitamins, homocysteine, and bone disease: Epidemiology and pathophysiology

Observational studies indicate that mildly elevated homocysteine is a strong risk factor for osteoporotic fracture, yet there is no clear biologic mechanism for an effect of homocysteine on bone. The association could instead be attributed to B vitamins (folate, vitamin B(12), vitamin B(6)), as low levels of these nutrients are the primary determinants of homocysteine and may be associated with lower bone quality. Discovery of a direct effect of homocysteine or B vitamins on bone would be important in terms of interventions, as these factors can be modified with changes in diet or supplementation. This article reviews the connections of homocysteine and B vitamins to measures of bone quality and osteoporotic fracture. Although the literature suggests that these factors may be associated with bone health, most of the epidemiologic studies are observational, limiting conclusions regarding causality. More controlled -trials are needed to determine whether treatment with B vitamins would reduce fracture rates among community-dwelling cohorts.

Ten-Year Risk of Osteoporotic Fractures in Postmenopausal Chinese Women According to Clinical Risk Factors and BMD T-Scores: A Prospective Study

Independent risk factors for osteoporotic fracture were identified for a Southern Chinese postmenopausal population. Clinical risk factor assessment with or without BMD measurement was shown to be an effective predictor of 10-yr risk of osteoporotic fracture and provides a more accessible tool for patient evaluation. Asian-specific data on risk factors for osteoporosis remain sparse. However, risk factor assessment, in addition to BMD measurement, is increasingly recognized as a reliable predictor of absolute osteoporotic fracture risk. The purpose of this prospective study was to determine the specific independent risk factors for osteoporotic fracture and to predict the 10-yr risk of osteoporotic fracture in the postmenopausal Southern Chinese population. A total of 1435 community-dwelling, postmenopausal, treatment-naive women were recruited. Baseline demographic characteristics and clinical risk factors were obtained, and BMD at the spine and hip was measured. Subjects were followed for outcomes of incident low trauma fracture. Ten-year risk of osteoporotic fracture was predicted from the risk factor assessment and BMD measurement by Cox proportional hazards models. The mean age of subjects was 63.4 +/- 8.3 yr. After 5.0 +/- 2.3 yr (range, 1.0-11.0 yr) of follow-up, 80 nontraumatic new fractures were reported during follow-up. Eight independent clinical risk factors identified at baseline were found to be significant predictors of osteoporotic fracture, with the most important being use of walking aids (RR, 4.2; 95% CI, 2.7-6.7; p < 0.001) and a history of fall (RR, 4.0; 95% CI, 2.5-6.2; p < 0.001). Other predictive factors included being homebound, calcium intake < 400 mg/d, age > 65 yr, history of fracture, and BMI < 19 kg/cm(2). Subjects with three to eight clinical risk factors had a predicted 10-year risk of osteoporotic fracture of 25%, which increased to 30% if they also had total hip BMD T-score <or= -2.5. Clinical risk factor assessment, with or without BMD measurement, is a reliable predictor of 10-year risk of osteoporotic fracture and may be particularly useful in regions or primary care clinics without access to bone densitometry equipment.

Homocysteine and fracture risk in postmenopausal women: the OFELY study

Homocysteine has recently been described as an independent risk factor for osteoporotic fractures in the elderly. We prospectively followed 671 postmenopausal women belonging to the OFELY study, mean age 62 years, during a mean follow-up of 10 years. After adjustment for age, there was no significant relation between the plasma level of homocysteine and the subsequent risk of fracture. Plasma homocysteine increases with age. Recent studies have described homocysteine as an independent risk factor for osteoporotic fractures in elderly. We investigated the role of plasma homocysteine in the subsequent risk of fractures in healthy ambulatory postmenopausal women. Homocysteine was measured at baseline in 671 postmenopausal women from the OFELY cohort (mean age 62.2 +/- 9 years). Incident clinical fractures were recorded during annual follow-up and vertebral fractures were evaluated with radiographs every four years. A cox proportional hazards model based on time to first fracture was used to calculate hazard ratios for quartiles of homocysteine values. Mean homocysteine was 10.6 +/- 3.4 mumol/l, increasing with age. After adjustment for age, homocysteine was significantly associated with physical activity, calcium intake, serum albumin and serum creatinine but not with bone turnover markers and bone mineral density. During a mean follow-up of 10 years, 183 fractures occurred among 134 women. After adjustment for age, the overall relative risk of fracture for each 1 SD increment of homocysteine was 1.03 (95%CI 0.87-1.31). Fracture risk was higher in women with homocysteine in the highest quartile without adjustment but no longer after adjustment for age. Homocysteine is not an independent risk factor of osteoporotic fractures in healthy postmenopausal women from the OFELY cohort with a broad age range.

Associations between the metabolic syndrome and bone health in older men and women: the Rancho Bernardo Study

We examined the associations of metabolic syndrome (MS) with BMD, osteoporosis, and osteoporotic fractures in 417 men and 671 women from the Rancho Bernardo Study. After adjusting for BMI, MS was associated with lower, not higher BMD. Incidence of osteoporotic non-vertebral fractures was higher in participants with MS. MS may be another risk factor for osteoporotic fractures. The metabolic syndrome (MS) is a cluster of risk factors, including abdominal obesity, high glucose, triglycerides, hypertension and low HDL levels, associated with cardiovascular disease morbidity. The association between components of the MS and bone mineral density (BMD) has been researched, but results are contradictory. We used multivariate regression models to examine the cross-sectional associations of MS defined by NCEP-ATP III criteria with BMD and osteoporosis, and the longitudinal association of MS with fractures in 420 men and 676 women from the Rancho Bernardo Study. Prevalence of MS at baseline was 23.5% in men and 18.2% in women. In age-adjusted analyses, men and women with MS had higher BMD at total hip when compared to those without MS (p < 0.001 and p = 0.01, respectively). Men but not women with MS also had higher BMD at femoral neck (p = 0.05). After adjusting for BMI, these associations were reversed, such that MS was associated with lower and not higher BMD. Incidence of osteoporotic non-vertebral fractures was higher in participants with MS. MS may be another risk factor for osteoporotic fractures. The association of MS with higher BMD was explained by the higher BMI in those with MS.

Relationship between serum hsCRP concentration and biochemical bone turnover markers in healthy pre‐ and postmenopausal women

Although osteoporosis and atherosclerosis seem to be related, the mechanisms are not yet understood. We previously observed that women with higher serum concentrations of high sensitivity C-reactive protein (hsCRP), a strong risk factor for atherosclerosis, had lower bone mineral density (BMD). However, the relationship of hsCRP level with bone turnover rate, an independent risk factor for osteoporotic fracture, is not known. Cross-sectional hospital-based survey. Apparently healthy pre- and postmenopausal women (n = 39 and 150, respectively). Urinary N-terminal telopeptide of type I collagen (NTx) and serum bone specific alkaline phosphatase (BALP) were measured using commercially available immunoassay kits. Serum hsCRP concentrations were measured by a particle-enhanced immunoturbidometric method. Both urinary NTx (gamma = 0.288, P < 0.001) and serum BALP (gamma = 0.260, P < 0.001) were positively correlated with serum hsCRP levels. Significance remained even after adjustment for age, body mass index and years since menopause (gamma = 0.257, P < 0.001, and gamma = 0.163, P = 0.027, respectively). Compared with subjects in the lowest hsCRP quartile (< or = 0.6 mg/l), those in the highest hsCRP quartile (> or = 1.6 mg/l) had significantly higher urinary NTx concentrations (P = 0.001) after adjustment for confounding variables. There was an increasing trend of serum BALP concentrations in the higher hsCRP quartile groups (P = 0.073). These findings suggest that low grade systemic inflammation may be a common linking factor between development of atherosclerosis and increased bone turnover rate.

Homocysteine, the vitamin B complex family and bone

Recent studies have identified a mildly elevated circulating homocysteine level as a new and potentially modifiable risk factor for osteoporotic fractures. However, these studies do not establish a causal relationship between increased serum homocysteine and fractures. In the present paper the current data on the effect of lowering homocysteine levels on fracture incidence is discussed. Furthermore, an overview is given of the different cellular and molecular mechanisms that can link high homocysteine concentrations and/or associated B vitamins with bone metabolism.

Age and drug therapy are key prognostic factors for first clinical fracture in patients with primary osteoporosis

We evaluated the characteristics of 1,142 women and men who attended Canadian osteoporosis clinics and had T-score < or = -2.0 and no prior fractures to determine the predictors of first clinical fracture. Greater age and failure to start osteoporosis drug treatment increased the risk of first clinical fracture. Although risk factors for osteoporotic fractures are well-known, it is unclear which factors predict poor prognosis in patients with primary osteoporosis. The purpose of this study was to determine prognostic factors for first clinical fracture in patients with T-score < or = -2.0 and no previous clinical fracture. We examined prospectively collected data from 1,142 patients aged 40 and over in the Canadian Database of Osteoporosis and Osteopenia. We used prognosis methodology and performed survival analysis to determine factors that increase the risk of first clinical fracture. Our inception cohort (mean age = 60.6 years, 91% females) had a cumulative fracture incidence of 5.1% (incidence rate: 2.53/100 person-years). Age and osteoporosis drug use predicted incident clinical fractures in multivariable regression analyses. The risk of first fracture increased by 3% per year. Failing to initiate osteoporosis treatment increased fracture risk by 2.4 times. In addition, low physical activity, high body mass index and low T-scores were found to predict fracture risk in certain patient subgroups using tree-structured survival analysis. These findings were robust and did not change with most sensitivity analyses. Age and osteoporosis drug treatment are the main prognostic predictors of first clinical fracture in patients with T-score < or = -2.0.

Lowering homocysteine with B vitamins has no effect on biomarkers of bone turnover in older persons: a 2-y randomized controlled trial

Background:In recent prospective studies, higher homocysteine concentrations were shown to be a risk factor for osteoporotic fractures in older persons. Supplements containing folate and vitamins B-12 and B-6 lower homocysteine concentrations.Objective:The objective of the study was to determine in healthy older persons whether lowering homocysteine with B vitamins affects plasma biomarkers of bone turnover.Design:Healthy older persons (n= 276; aged ≥65 y) were randomly assigned to receive either a daily supplement containing folate (1 mg), vitamin B-12 (500 μg), and vitamin B-6 (10 mg) or a placebo for 2 y. Of these participants, we selected 135 with baseline homocysteine concentrations >15.0 μmol/L, and we measured serum bone-specific alkaline phosphatase, a marker of bone formation, and bone-derived collagen fragments, a marker of bone resorption, at baseline and 2 y later.Results:At 2 y, plasma homocysteine concentrations were 5.2 μmol/L (95% CI: 3.9, 6.6 μmol/L; P< 0.001) lower in the vitamin than in the placebo group. No significant differences were found in either serum bone-specific alkaline phosphatase (−0.3 μg/L; 95% CI: −2.8, 2.1 μg/L; P= 0.79) or bone-derived collagen fragments (−0.0 μg/L; 95% CI: −0.1, 0.1 μg/L; P= 0.76) between the vitamin and placebo groups, respectively, with 2 y of supplementation.Conclusion:Supplementation with folate and vitamins B-6 and B-12 lowered plasma homocysteine but had no beneficial effect on bone turnover at the end of 2 y, as assessed by biomarkers of bone formation and resorption.

Hyperhomocysteinaemia: A Critical Review of Old and New Aspects

Hyperhomocysteinemia (HHCY) is a risk factor for cardiovascular (CVD) and neurodegenerative diseases, osteoporotic fractures and pregnancy complications. HHCY is common and is mostly related to B-vitamin deficiency. Retrospective and prospective studies emphasise the causal relationship between HHCY and CVD risk. Some reported vitamin intervention trials, however, did not demonstrate lower risk of CVD after treatment. Confounding factors on the one hand and low subject numbers on the other hand reduced the statistical power of the results. Re-analysis of the VISP study (after excluding renal failure and vitamin B12 status tampering factors), detected a 21% decrease in the risk of stroke. This number has been confirmed by results from the HOPE 2 vitamin intervention trial. A significant decline of stroke-mortality (8 to 16%) has been observed in the USA and Canada after fortification of grain products with folate. Despite negative results from secondary prevention trials regarding the CVD risk reduction there is convincing evidence about the effectiveness of B-vitamin supplementation in lowering the risk of stroke (approximately 20%). Additionally, HHCY was recently linked to the occurrence and severity of chronic heart insufficiency. HHCY is also a risk factor for osteoporotic fractures and vitamin treatment can lower the fracture risk. HHCY predicts the decline in cognitive function with age. Hypomethylation is among the central mechanisms through which HHCY may damage the brain. HHCY and low folate are causal factors for pregnancy complications. In addition to the recommended folate supplementation, vitamin B12 supplementation may also decrease pregnancy complications.

Characterisation of Patients with Postmenopausal Osteoporosis in French Primary Healthcare

The public health burden of osteoporosis is high, principally because of increased risk of fractures and associated morbidity, handicap and mortality. Osteoporotic fracture prevention is therefore an important public health goal. General practitioners (GPs) play a key role in the management of osteoporosis, both in ensuring timely diagnosis and in providing treatment. Little information is available on standards of care for postmenopausal women with osteoporosis in general practice. The primary objective of this study was to describe risk factors and treatment in postmenopausal women with osteoporosis. Secondary objectives were to evaluate treatment compliance and to assess the impact of osteoporosis on quality of life. This observational, cross-sectional, pharmacoepidemiological study was performed in a primary-care setting in France. A random sample of GPs recruited postmenopausal women with a diagnosis of osteoporosis who had been followed by the investigator for at least 2 years. At inclusion, investigators completed a questionnaire providing information on patient age, osteoporosis duration, risk factors and treatment history. The first three patients recruited by each investigator completed a questionnaire providing information on sociodemographic features, osteoporosis treatments and quality of life. Treatment compliance was quantified using the Test d'Evaluation de l'Observance and quality of life evaluated using the 12-item Short Form Health Survey (SF-12). Overall, 389 physicians included 3,097 patients, of whom 1,053 completed the patient questionnaire. Risk factors for osteoporotic fracture were identified in 2,148 patients (69.4%), most frequently personal or maternal antecedents of osteoporotic fracture and a low body mass index. Of these, 946 (44.0%) presented more than one risk factor. At the time of diagnosis, 629 patients (59.7%) presented fractures, which involved the vertebrae in 51.7% of cases, the wrist in 40.5% and the hip in 5.4%. Older patients were more likely to have fractures at the time of diagnosis and to have multiple fractures. After diagnosis, at least one new fracture occurred in 201 patients (19.2%). Multivariate logistic regression analysis identified age >70 years, diagnosis at least 10 years previously, diagnosis based on the presence of a fracture, biochemical and haematological evaluation at the time of diagnosis, and a change in osteoporosis treatment in the previous 2 years as being significantly associated with incident fracture risk. At inclusion, 1,019 patients (97.4%) were receiving treatment for osteoporosis, most frequently weekly bisphosphonates (71.6% of treatments). Most patients (81.0%) had been treated for at least 1 year. Treatment compliance was high in 61% of patients and low in <5%. Patient variables associated with high compliance were being retired, prescription of bisphosphonates and, among the bisphosphonate users, prescription of weekly formulations. SF-12 quality-of-life scores were low, ranging from 38.6 (energy/vitality) to 65.1 (social functioning) out of a possible maximum score of 100. Baseline variables associated with SF-12 physical component summary scores included age, height loss since menopause, diagnosis following a fracture, fracture incidence since diagnosis, time since diagnosis and treatment with bisphosphonates. In this study of postmenopausal osteoporosis in the French primary healthcare setting, many women with osteoporosis were diagnosed following a fracture. Although most were treated with bone-consolidating drugs, compliance was suboptimal in a significant minority. Osteoporotic fracture was associated with reduced quality of life.

Postural stabilizing effect of alfacalcidol and active absorbable algal calcium (AAA Ca) compared with calcium carbonate assessed by computerized posturography

Sway and postural instability have drawn attention as a risk factor for osteoporotic fracture, in addition to low bone mineral density (BMD) and poor bone quality. In view of the fracture-reducing effect of alfacalcidol and active absorbable algal calcium (AAA Ca) not readily explained by rather mild increases of BMD, attempts were made to evaluate postural stabilizing effect of alfacalcidol, AAA Ca, and calcium carbonate (CaCO(3)) by computerized posturography. Track of the gravity center was analyzed to calculate parameters related to tract length, track range, and track density to express the degree of sway before and after supplementation in 126 subjects ranging in age between 20 and 81 years randomly divided into four groups. Supplementation with AAA Ca containing 900 mg elemental Ca (group A), no calcium (group B), CaCO(3) also containing 900 mg elemental Ca (group C), or alfacalcidol (group D) continued daily for 12 months. For each parameter, the ratio closed eye value/open eye value (Romberg ratio) was calculated to detect aggravation of sway by eye closure. Age, parameters of Ca and P, and proportions of subjects with fracture and those with low BMD showed no marked deviation among the groups. With eyes open, significant decreases of a track range parameter (REC) from group B was noted in groups A (P = 0.0397) and D (P = 0.0296), but not in group C according to multiple comparison by Scheffe, indicating superior postural stabilizing effect of A and D over C. In the first 2 months, a significant fall was already evident in REC from group B in group D (P = 0.0120) with eyes open. Paired comparison of sway parameters before and after supplementation revealed a significant increase of track density parameter (LNGA), indicating sway control efficiency and a significant decrease of REC in groups A and D compared to group B with eyes open. With eyes closed, only group A showed a significant improvement from group B (P = 0.0456; Fig. 1), with a significant shortening on paired After/Before comparison (P = 0.0142; Fig. 2). Computerized posturography appears to be useful in analyzing sway phenomena especially as to the effects of vitamin D and various Ca preparations.

Steroids as a risk factor for osteoporotic fracture

Glucocorticoid is effective medicines for the treatment of, such as, collagen diseases, pulmonary diseases, skin diseases, organ transplantation, however, glucocorticoid induced osteoporosis have been a serious problem. Glucocorticoid is not only associated with decreased bone mineral density (BMD), but also with deteriorated bone quality, so osteoporotic fracture can occur even at slightly lower BMD. Recent studies have shown that long-term use of inhaled glucocorticoid at high doses is also associated with increased risk for fracture. Osteoporotic fracture decreases not only the abilities of daily living and the quality of life, but also to increase mortality, so earlier prevention for glucocorticoid induced osteoporosis is necessary at administration of glucocorticoid.

No associations between OPG gene polymorphisms or serum levels and measures of osteoporosis in elderly Australian women

Bone mass is the single most important risk factor for osteoporotic fractures in the elderly and is mainly influenced by genetic factors accounting for 40–75% of the inter-individual variation. Critical for the bone remodeling process is the balance between the newly discovered members of the tumor necrosis factor ligand and receptor superfamilies, osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand, which mediate the effects of many upstream regulators of bone metabolism. In the present study, we evaluated the impact of sequence variations in the OPG gene on bone mass, bone-related biochemistry including serum OPG and fracture frequency in elderly Australian women. A total of 1101 women were genotyped for 3 different single nucleotide polymorphisms (SNP) within the OPG gene (G1181C, T950C and A163G). The effects of these SNPs and serum OPG on calcaneal quantitative ultrasound measurements, osteodensitometry of the hip and bone-related biochemistry were examined. We found no significant relationship between sequence variations in the OPG gene or serum OPG and bone mass, bone-related biochemistry or fracture frequency. Our findings confirm some recent publications investigating the same SNPs but diverge from others, indicating that generalization of the relationships found in this type of study must be done with caution and signify the importance of determining associations between polymorphisms and osteoporosis in different ethnic groups.

Bone tissue compositional differences in women with and without osteoporotic fracture

It is generally accepted that the hallmark of osteoporosis is a reduction in bone mass. There is significant overlap, however, in bone mineral density between osteoporotic and normal individuals. This study examined the chemical composition of bone tissue obtained from women who had sustained a fracture and women without fracture to determine if there are differences between the two groups. Nineteen fractured and eleven non-fractured proximal femurs were obtained, matched for age and bone volume fraction obtained from micro-computed tomography. Trabecular bone specimens were examined by Raman spectroscopy to determine measures of chemical composition. A subset of the specimens was utilized to compare locations at the fracture and regions at least 2 mm away from apparent tissue damage using Raman spectroscopy. In addition, fifteen iliac crest biopsies each were obtained from women who had sustained a fracture and from normal controls. Raman spectroscopy was used to determine measures of chemical composition of trabecular and cortical bone. The results demonstrated that femoral bone tissue in the region of visible damage had a trend towards differences compared to regions at least 2 mm from visible damage. Femoral trabecular bone in fractured women had a higher carbonate/amide I area ratio than in unfractured women. Iliac crest biopsies revealed a higher carbonate/phosphate ratio in cortical bone from women who had sustained a fracture. Results suggest that the chemical composition of bone tissue may be an additional risk factor for osteoporotic fracture.

Linkage exclusion mapping with bone size in 79 Caucasian pedigrees

Bone size is an important risk factor of osteoporotic fractures and has strong genetic determination. However, genetic studies on bone size variation are relatively rare. In the present study, we conducted a linkage exclusion mapping for bone size variation on chromosomes 1, 4, 6, and 17 in 79 Caucasian pedigrees. For hip bone size variation, several genomic regions were excluded at effect sizes of 10% or greater, including regions of 61-77cM at 1p35-p34, 43-59cM at 4p15-p13, 1-59cM at 6p25-p21, 82-88cM at 17q23-q24, and 113-114cM at 17q25. For spine bone size, at effect sizes of 10% or greater, we excluded regions of 115-122cM at 1p31-p22, 136-141cM at 1p21, 207-260cM at 1q31-q42, 20-89cM at 4p16-q21, 11-21cM at 6p24-p23, and 1-6cM at 17p13. These results suggested that a number of candidate genes located in the excluded regions, such as the growth hormone (GH) gene, tumor necrosis factor-alpha (TNF-alpha) gene, and bone morphogenetic protein-3 (BMP3) gene, are unlikely to have a substantial effect on bone size variation in this Caucasian population.

The interaction of ethnicity and chronic disease as risk factors for osteoporotic fractures: a comparison in Canadian Aboriginals and non-Aboriginals

Efforts to develop global methods for absolute fracture risk prediction are currently limited by uncertainty over the validity of these models in non-White populations. Aboriginal Canadians have higher fractures rates than non-Aboriginals. This analysis examined the interaction of ethnicity with diabetes mellitus, disease comorbidity and substance abuse as possible explanatory variables. A retrospective, population-based matched cohort study of fracture rates was performed using Manitoba administrative health data (1984-2003). The study cohort consisted of 27,952 registered Aboriginal adults (aged 20 years or older) and 83,856 non-Aboriginal controls (matched three to one for year of birth and gender). Diabetes mellitus, number of ambulatory disease groups (ADGs), substance abuse and incident fractures were based upon validated definitions. Poisson regression analyses of fracture rates modelled the explanatory variables as main effects and two-way interactions with ethnicity. Osteoporotic fracture rates were approximately twofold higher in the Aboriginal cohort (p<0.0001). Diabetes, greater number of ADGs and substance abuse were all more common in the Aboriginal cohort (all p<0.0001). These factors were associated with increased fracture rates (all p<0.0001) and significantly higher population attributable risk percent in the Aboriginal cohort (all p<0.0001). However, no significant interactions between the risk factors and ethnicity were observed (p>0.1 for all interaction effects). Greater prevalence of diabetes, comorbidity and substance abuse contributes to higher rates of fracture. The relative risk of fracture for these factors is similar for both Aboriginal and non-Aboriginals despite large differences in absolute fracture risk and risk factor prevalence.

Long-term recreational gymnastics provides a clear benefit in age-related functional decline and bone loss. A prospective 6-year study

Bone fragility and decreased functional performance are risk factors for osteoporotic fractures. The influence of long-term recreational gymnastics on the maintenance of bone rigidity and physical performance was evaluated. One hundred and seven gymnasts and 110 referents (93% of the original sample) participated in this 6-year prospective study. Analysis of covariance (ANCOVA) was used to estimate the between-group differences and changes by time, and regression analyses to find predictors for changes. In both groups agility and leg extensor power decreased by over 3% and 10%, respectively, but the original between-group differences, favoring the gymnasts, persisted. Proximal femur bone mineral content (BMC) decreased approximately 0.5% per year in both groups, and femoral neck section modulus decreased. Trabecular density of the distal tibia declined only marginally, and cortical area of the tibial midshaft remained unchanged, while cortical density decreased about 2% in both groups. After adjustment by age, height, weight, change in weight, and follow-up time, antiresorptive medication and high calcium intake accounted most for the maintenance of bone rigidity. In spite of similar rates of decline in bone characteristics and physical performance, the recreational gymnasts' overall physical condition was comparable to the level that their less active referents had shown approximately 5 years earlier.

Association of Geometric Factors and Failure Load Level With the Distribution of Cervical vs. Trochanteric Hip Fractures

We experimentally studied the distribution of hip fracture types at different structural mechanical strength. Femoral neck fractures were dominant at the lowest structural strength levels, whereas trochanteric fractures were more common at high failure loads. The best predictor of fracture type across all failure loads and in both sexes was the neck-shaft angle. Bone geometry has been shown to be a potential risk factor for osteoporotic fractures. Risk factors have been shown to differ between cervical and trochanteric hip fractures. However, the determinants of cervical and trochanteric fractures at different levels of structural mechanical strength are currently unknown. In addition, it is not known if the distribution of fracture types differs between sexes. The aim of this experimental study on excised femora was to investigate whether there exist differences in the distribution of cervical and trochanteric fractures between different structural mechanical strength levels and different sexes and to identify the geometric determinants that predict a fracture type. The sample was comprised of 140 cadavers (77 females: mean age, 81.7 years; 63 males: mean age, 79.1 years) from whom the left femora were excised for analysis. The bones were radiographed, and geometrical parameters were determined from the digitized X-rays. The femora were mechanically tested in a side impact configuration, simulating a sideways fall. After the mechanical test, the fracture patterns were classified into cervical and trochanteric. The overall proportion of cervical fractures was higher in females (74%) than in males (49%) (p = 0.002). The fracture type distribution differed significantly across load quartiles in females (p = 0.025), but not in males (p = 0.205). At the lowest load quartiles, 94.7% of fractures in female and 62.5% in males were femoral neck fractures. At the highest quartiles, in contrast, only 52.6% of fractures in females and 33.3% in males were cervical fractures. Among geometric variables, the neck-shaft angle was the best predictor of fracture type, with higher values in subjects with cervical fractures. This finding was made in females (p < 0.001) and males (p = 0.02) and was consistent across all failure load quartiles. Femoral neck fractures predominate at the lowest structural mechanical strength levels, whereas trochanteric fractures are more common at high failure loads. Females are more susceptible to femoral neck fractures than males. The best predictor of fracture type across all structural strength levels and both sexes was the neck-shaft angle.