Guidelines for the management of postmenopausal osteoporosis for GPs

BACKGROUND : Since the last series of guidelines on the management of osteoporosis from Osteoporosis Australia was published in Australian Family Physician (October 2002), there have been further advances in our understanding of the treatment involved in both the prevention of bone loss and the management of established osteoporosis.

OBJECTIVE : This article provides updated guidelines for the management of postmenopausal osteoporosis to assist general practitioners identify those women at risk, and reviews current treatment strategies.

DISCUSSION : Osteoporosis and its associated problems are major health concerns in Australia, especially with an aging population. While important principles of management are still considered to be maximising peak bone mass and preventing postmenopausal bone loss, new clinical trial data about drugs such as the bisphosphonatesr raloxifene and oestrogen have recently become available and the relative role of various agents is gradually becoming clearer. The use of long term hormone therapy has mixed risks and benefits that requires individual patient counselling.

The effect of osteoporotic vertebral fracture of predicted spinal loads in vivo

he aetiology of osteoporotic vertebral fractures is multi-factorial, and cannot be explained solely by low bone mass. After sustaining an initial vertebral fracture, the risk of subsequent fracture increases greatly. Examination of physiologic loads imposed on vertebral bodies may help to explain a mechanism underlying this fracture cascade. This study tested the hypothesis that model-derived segmental vertebral loading is greater in individuals who have sustained an osteoporotic vertebral fracture compared to those with osteoporosis and no history of fracture. Flexion moments, and compression and shear loads were calculated from T2 to L5 in 12 participants with fractures (66.4 ± 6.4 years, 162.2 ± 5.1 cm, 69.1 ± 11.2 kg) and 19 without fractures (62.9 ± 7.9 years, 158.3 ± 4.4 cm, 59.3 ± 8.9 kg) while standing. Static analysis was used to solve gravitational loads while muscle-derived forces were calculated using a detailed trunk muscle model driven by optimization with a cost function set to minimise muscle fatigue. Least squares regression was used to derive polynomial functions to describe normalised load profiles. Regression co-efficients were compared between groups to examine differences in loading profiles. Loading at the fractured level, and at one level above and below, were also compared between groups. The fracture group had significantly greater normalised compression (p = 0.0008) and shear force (p < 0.0001) profiles and a trend for a greater flexion moment profile. At the level of fracture, a significantly greater flexion moment (p = 0.001) and shear force (p < 0.001) was observed in the fracture group. A greater flexion moment (p = 0.003) and compression force (p = 0.007) one level below the fracture, and a greater flexion moment (p = 0.002) and shear force (p = 0.002) one level above the fracture was observed in the fracture group. The differences observed in multi-level spinal loading between the groups may explain a mechanism for increased risk of subsequent vertebral fractures. Interventions aimed at restoring vertebral morphology or reduce thoracic curvature may assist in normalising spine load profiles.

Tennis playing initiated before puberty leads to greater skeletal benefits in peri-pubertal boys than girls when training is maintained

Introduction: The purpose of the study was to compare the exercise-induced changes in bone mass and geometry between boys and girls.

Methods: Eighty competitive tennis players (43 boys, 37 girls) aged 7–19 years participated. Pubertal status was self-assessed using Tanner stages (TS 1–5). The dominant and nondominant humeri were compared for DXA-derived bone mass (BMC) and MRI-derived bone geometry [total bone area (TA), medullary area (MA) and cortical bone area (CA)].

Results/Discussion: Exercise-induced side-to-side differences in BMC, TA and CA were significant from TS1 to 5 in boys and girls (p < 0.06). Pre-pubertal (TS1) girls and boys show similar side-to-side difference in BMC after adjustment for training volume (19% vs. 15%, ns). Similar findings were found forTA and CA. In contrast, during puberty (TS2-4) boys displayed greater side-to-side differences than girls for BMC (27% vs. 18%, p < 0.05), TA (13–15% vs. 8%, p < 0.05) and CA (32% vs. 20%, p < 0.01), even after adjustment for tennis history. Girls partly compensated for the lack of an exercise-induced increase in bone size by a reduction of the medullary cavity on the dominant side (−5.5 to −13%, p < 0.05). In post-puberty (TS 5 or postmenarche), the size of the medullary cavity remained smaller on the dominant side in girls (−5% to −9%, p = 0.1–0.05??) whereas no such reduction was observed in boys.

Conclusion: Regular exercise initiated before puberty and maintained throughout puberty leads to greater skeletal benefits in peri-pubertal boys than girls for bone mass and bone size, two of the major determinants of bone strength.

Skeletal benefits after long-term retirement in former elite female gymnasts

Bone strength benefits after long-term retirement from elite gymnastics in terms of bone geometry and volumetric BMD were studied by comparing retired female gymnasts to moderately active age-matched women. In a cross-sectional study, 30 retired female gymnasts were compared with 30 age-matched moderately active controls. Bone geometric and densitometric parameters were measured by pQCT at the distal epiphyses and shafts of the tibia, femur, radius, and humerus. Muscle cross-sectional areas were assessed from the shaft scans. Independent t-tests were conducted on bone and muscle variables to detect differences between the two groups. The gymnasts had retired for a mean of 6.1 ± 0.4 yr and were engaged in ≤2 h of exercise per week since retirement. At the radial and humeral shafts, cortical cross-sectional area (CSA), total CSA, BMC, and strength strain index (SSIpol) were significantly greater (13–38%, p ≤ 0.01) in the retired gymnasts; likewise, BMC and total CSA were significantly greater at the distal radius (22–25%, p ≤ 0.0001). In the lower limbs, total CSA and BMC at the femur and tibia shaft were greater by 8–11%, and trabecular BMD and BMC were only greater at the tibia (7–8%). Muscle CSA at the forearm and upper arm was greater by 15–17.6% (p ≤ 0.001) but was not different at the upper and lower leg. Past gymnastics training is associated with greater bone mass and bone size in women 6 yr after retirement. Skeletal benefits were site specific, with greater geometric adaptations (greater bone size) in the upper compared with the lower limbs.

Patterns of treatment in Australian men following fracture

Summary This study aimed to describe treatment initiation rates for men who had recently sustained a fracture. Most (75.9%) men potentially eligible for subsidised treatment at the time of fracture remained untreated even after a subsequent fracture.

Introduction This study aimed to describe treatment initiation rates for men who had recently sustained a fracture.

Methods The study was conducted as part of the Geelong Osteoporosis Study in south-eastern Australia. Men in the study area who had sustained an incident fracture in the period July 2006 to December 2007 were identified from hospital radiology reports. A self-report questionnaire was sent to eligible participants approximately 12 months after fracture. Respondents were asked for details of medications prescribed for ‘osteoporosis/fracture/low bone mass’ before and after fracture, and where applicable, reasons for cessation of treatment.We analysed the results for 109 men aged 50 years and older who had sustained fracture in the study period.

Results Most (75.9%) men potentially eligible for subsidised treatment at the time of fracture remained untreated. Of the 87 men who were untreated, nine had osteoporosis at the hip and/or spine and 29 (26.6%) reported having sustained a low trauma prior fracture.

Conclusions Our findings are consistent with previously published data showing low rates of treatment initiation in men eligible for osteoporosis treatment. There appear to be barriers involving participants’ and medical practitioners’ knowledge, beliefs and attitudes regarding osteoporosis and treatment, as well as in the doctor–patient partnership in osteoporosis management. Establishment of clinical pathways for fracture management beyond orthopaedic care may be one of a range of appropriate responses.

Anthropometric profiling of elite junior and senior Australian football players

Purpose: Body structure and physical development must be addressed when preparing junior athletes for their first season in a senior competition. The aim of this preliminary study was to measure the extent of the assumption that final year junior Australian Football (AF) athletes are at a physical mismatch to their senior counterparts.

Methods: Twenty-one male participants (17.71 ± 0.27 y) were recruited from one state based elite junior AF competition and forty-one male participants (22.80 ± 4.24 y) were recruited from one club competing in the senior elite Australian Football League (AFL), who were subsequently divided into two groups; professional rookies aged 18-20 y (19.44 ± 0.70 y; n = 18) and professional seniors aged 21+ y (25.43 ± 3.98 y; n = 23). Dual energy X-ray absorptiometry (DEXA) scans of all participants were completed.

Results: Despite being an average 6.0% and 6.1% lighter in total weight and lean mass respectively, no significant difference was found between the elite junior athletes and their professional AFL rookie counterparts. However, significant differences were demonstrated in comparison with the professional AFL senior athletes (P < .01). Both professional AFL groups demonstrated greater than 0.3 kg total bone mineral content (BMC) than the elite junior athletes (P < .01) and significantly greater segmental BMC and bone mineral density (BMD) results (P < .05).

Conclusion: While the results identify the differences in body composition of the elite junior athletes, development in a linear fashion is noted, providing useful information for the creation of age appropriate expectations and training programs.

Musculoskeletal deterioration in men accompanies increases in body fat

Objective
To examine body fat and musculoskeletal changes in men over 5 years.

Methods
Body composition was evaluated for men in the Geelong Osteoporosis Study using whole body dual energy X-ray absorptiometry (DXA) during two time-periods. DXA was performed for 1329 men (25-96 years) during 2001-2006 and for 900 men (25-98 years), 2006-2011. The masses of fat, lean, and bone were expressed relative to the square of height (kg/m2). Each compartment was also expressed as a percentage relative to body weight (%fat, %lean, %bone).

Results
Mean BMI increased from 26.9 kg/m2 in 2001-2006, to 27.2 kg/m2 in 2006-2011 (P = 0.04). Mean fat mass increased by 9.0% from 6.98 kg/m2 (95%CI 6.84-7.11) in 2001-2006, to 7.60 kg/m2 (7.44-7.77) in 2006-2011 (P < 0.001); mean lean mass decreased by 0.9%, from 18.92 kg/m2 (18.83-19.01) to 18.75 kg/m2 (18.64-18.86) (P = 0.02), and mean bone mass decreased 1.6% from 1.041 kg/m2 (1.034-1.047), to 1.024 kg/m2 (1.016-1.032). Mean %fat increased from 23.4% to 25.2%, mean %lean decreased from 72.6% to 70.9% and mean %bone decreased from 4.0% to 3.9% (all P < 0.05).

Conclusions
An increase in BMI, which reflects a substantial increase in body fat mass and declines in both lean and bone mass was reported. This may have implications for future development of bone fragility, sarcopenia, and sarcopenic obesity.

Physical activity and exercise in the maintenance of the adult skeleton and the prevention of osteoporotic fractures

In the prevention of osteoporosis and osteoporoticrelated fractures, strategies aimed at maximizing peak bone mass during childhood and adolescence; maintaining or attenuating bone loss during the adult years; and increasing or preserving muscle mass, strength, power, and function are all considered critical. To this end, physical activity and exercise are recognized as important modifiable lifestyle variables that can strengthen the skeleton and muscles and reduce the risk of falls and subsequent fracture, as well as enhance quality of life... 

(1)H-NMR analysis of the human urinary metabolome in response to an 18-month multi-component exercise program and calcium-vitamin-D3 supplementation in older men

The musculoskeletal benefits of calcium and vitamin-D3 supplementation and exercise have been extensively studied, but the effect on metabolism remains contentious. Urine samples were analyzed by (1)H-NMR spectroscopy from participants recruited for an 18-month, randomized controlled trial of a multi-component exercise program and calcium and vitamin-D3 fortified milk consumption. It was shown previously that no increase in musculoskeletal composition was observed for participants assigned to the calcium and vitamin-D3 intervention, but exercise resulted in increased bone mineral density, total lean body mass, and muscle strength. Retrospective metabolomics analysis of urine samples from patients involved in this study revealed no distinct changes in the urinary metabolome in response to the calcium and vitamin-D3 intervention, but significant changes followed the exercise intervention, notably a reduction in creatinine and an increase in choline, guanidinoacetate, and hypoxanthine (p < 0.001, fold change > 1.5). These metabolites are intrinsically involved in anaerobic ATP synthesis, intracellular buffering, and methyl-balance regulation. The exercise intervention had a marked effect on the urine metabolome and markers of muscle turnover but none of these metabolites were obvious markers of bone turnover. Measurement of specific urinary exercise biomarkers may provide a basis for monitoring performance and metabolic response to exercise regimes.

Muscle metabolism, nutrition, and functional status in older adults

In the last 50 years, the number of individuals over the age of 65 years in the United States has doubled. A further doubling is expected by 2030, dramatically increasing the number of adults at risk of sarcopenia, a condition characterized by an age-related loss of muscle mass with an associated reduction in physical function. A reduction in muscle mass and functional capacity is typically viewed as an undesirable, yet inevitable, consequence of aging, and in its early stages, may be easily masked by subtle lifestyle adaptations. However, advanced sarcopenia is synonymous with physical frailty and is associated with an increased likelihood of falls and impairments in the ability to perform routine activities of daily living. In many instances, the progression of sarcopenia is mirrored by a decrease in physical activity, which feeds into a vicious cycle of disuse and negative outcomes, including impaired insulin action, accelerated loss of muscle and bone mass, fatigue, impaired motor control and functional capacity, and increased morbidity and mortality.

Musculoskeletal asymmetry in football athletes: A product of limb function over time.

PURPOSE: Asymmetrical loading patterns are commonplace in football sports. Our aim was to examine the influence of training age and limb function on lower-body musculoskeletal morphology. METHODS: Fifty-five elite football athletes were stratified into less experienced (≤3 yr; n = 27) and more experienced (>3 yr; n = 28) groups by training age. All athletes underwent whole-body dual-energy x-ray absorptiometry scans and lower-body peripheral quantitative computed tomography tibial scans on the kicking and support limbs. RESULTS: Significant interactions between training age and limb function were evident across all skeletal parameters (F16, 91 = 0.182, P = 0.031, Wilks Λ = 0.969). Asymmetries between limbs were significantly larger in the more experienced players than the less experienced players for tibial mass (P ≤ 0.044, d ≥ 0.50), total cross-sectional area (P ≤ 0.039, d ≥ 0.53), and stress-strain indices (P ≤ 0.050, d ≥ 0.42). No significant asymmetry was evident for total volumetric density. More experienced players also exhibited greater lower-body tibial mass (P ≤ 0.001, d ≥ 1.22), volumetric density (P ≤ 0.009, d ≥ 0.79), cross-sectional area (P ≤ 0.387, d ≥ 0.21), stress-strain indices (P ≤ 0.012, d ≥ 0.69), fracture loads (P ≤ 0.018, d ≥ 0.57), and muscle mass and cross-sectional area (P ≤ 0.016, d ≥ 0.68) than less experienced players. CONCLUSIONS: Asymmetries were evident in athletes as a product of limb function over time. Chronic exposure to routine high-impact gravitational loads afforded to the support limb preferentially improved bone mass and structure (cross-sectional area and cortex thickness) as potent contributors to bone strength relative to the high-magnitude muscular loads predominantly afforded to the kicking limb.

Overweight children have a greater proportion of fat mass relative to muscle mass in the upper limbs than in the lower limbs : implications for bone strength at the distal forearm

Background: The influence of adiposity on upper-limb bone strength has rarely been studied in children, despite the high incidence of forearm fractures in this population.

Objective: The objective was to compare the influence of muscle and fat tissues on bone strength between the upper and lower limbs in prepubertal children.

Design: Bone mineral content, total bone cross-sectional area, cortical bone area (CoA), cortical thickness (CoTh) at the radius and tibia (4% and 66%, respectively), trabecular density (TrD), bone strength index (4% sites), cortical density (CoD), stress-strain index, and muscle and fat areas (66% sites) were measured by using peripheral quantitative computed tomography in 427 children (206 boys) aged 7–10 y.

Results: Overweight children (n = 93) had greater values for bone variables (0.3–1.3 SD; P < 0.0001) than did their normal-weight peers, except for CoD 66% and CoTh 4%. The between-group differences were 21–87% greater at the tibia than at the radius. After adjustment for muscle cross-sectional area, TrD 4%, bone mineral content, CoA, and CoTh 66% at the tibia remained greater in overweight children, whereas at the distal radius total bone cross-sectional area and CoTh were smaller in overweight children (P < 0.05). Overweight children had a greater fat-muscle ratio than did normal-weight children, particularly in the forearm (92 ± 28% compared with 57 ± 17%). Fat-muscle ratio correlated negatively with all bone variables, except for TrD and CoD, after adjustment for body weight (r = −0.17 to −0.54; P < 0.0001).

Conclusions: Overweight children had stronger bones than did their normal-weight peers, largely because of greater muscle size. However, the overweight children had a high proportion of fat relative to muscle in the forearm, which is associated with reduced bone strength.