The effect of calcium supplementation on bone density in premenarcheal females: a co-twin approach

The age and developmental stage at which calcium supplementation produces the greatest bone effects remain controversial. We tested the hypothesis that calcium supplementation may improve bone accrual in premenarcheal females. Fifty-one pairs of premenarcheal female twins (27 monozygotic and 24 dizygotic; mean ± SD age, 10.3 ± 1.5 yr) participated in a randomized, single-blind, placebo-controlled trial with one twin of each pair receiving a 1200-mg calcium carbonate (Caltrate) supplement. Areal bone mineral density (aBMD) was measured at baseline and 6, 12, 18 and 24 months. There were no within-pair differences in height, weight, or calcium intake at baseline. Calcium supplementation was associated (P < 0.05) with increased aBMD compared with placebo, adjusted for age, height, and weight at the following time points from baseline: total hip, 6 months (1.9%), 12 months (1.6%), and 18 months (2.4%); lumbar spine, 12 months (1.0%); femoral neck, 6 months (1.9%). Adjusted total body bone mineral content was higher in the calcium group at 6 months (2.0%), 12 months (2.5%), 18 months (4.6%), and 24 months (3.7%), respectively (all P < 0.001). Calcium supplementation was effective in increasing aBMD at regional sites over the first 12–18 months, but these gains were not maintained to 24 months.

Calcium and bone health : position statement for the Australian and New Zealand Bone and Mineral Society, Osteoporosis Australia and the Endocrine Society of Australia

This position statement was prepared by the Working Group of the Australian and New Zealand Bone and Mineral Society and Osteoporosis Australia. The final statement was endorsed by the Endocrine Society of Australia.

Currently, the balance of evidence remains in favour of fracture prevention from combined calcium and vitamin D supplementation in elderly men and women.

Adequate vitamin D status is essential for active calcium absorption in the gut and for bone development and remodelling.

In adults with a baseline calcium intake of 500–900 mg/day, increasing or supplementing this intake by a further 500–1000 mg/day has a beneficial effect on bone mineral density.

Calcium intake significantly above the recommended level is unlikely to achieve additional benefit for bone health.

Association between changes in habitual physical activity and changes in bone density, muscle strength, and functional performance in elderly men and women

OBJECTIVES: To investigate the long-term effects of habitual physical activity on changes in musculoskeletal health, functional performance, and fracture risk in elderly men and women.

DESIGN: Ten-year prospective population-based study.

SETTING: Malmö-Sjöbo Prospective Study, Sweden.

PARTICIPANTS: Participants were 152 men and 206 women aged 50, 60, 70, and 80 who were followed for 10 years.

MEASUREMENTS: Distal radius bone mineral density (BMD) (single photon absorptiometry), upper limb muscle (grip) strength, balance, gait velocity, occupational and leisure-time activity, and fractures (interview-administered questionnaire) were reassessed after 10 years. Annual changes for all measures were compared between participants with varying habitual physical activity histories at baseline and follow-up: inactive–inactive (n=202), active–inactive (n=47), inactive–active (n=49), and active–active (n=60). Data for men and women were pooled, because there were no sex-by-activity group interactions. To detect possible differences in fracture incidence between the varying habitual activity groups, participants were classified into two activity groups based on their activity classification at baseline and follow-up: inactive:less active versus active:more active.

RESULTS: The annual rate of bone loss was 0.6% per year less in individuals classified as active at both time points than in those classified as inactive at both time points (P<.01). Similar results were observed for balance, but there was no effect of varying habitual activity on changes in muscle strength or gait velocity. There were also no differences in fracture incidence between individuals categorized as active:more active and those categorized as inactive:less active during the follow-up (adjusted hazard ratio=0.90, 95% confidence interval (CI)=0.42–1.90).

CONCLUSION: This study showed that elderly men and women who maintained a habitually active lifestyle over 10 years had lower bone loss and retained better balance than those who remained habitually inactive.

Gender specific age-related changes in bone density, muscle strength and functional performance in the elderly: a-10 year prospective population-based study

Background: 

Who are the older Australians referred for a bone density scan? Data from the Barwon region

We investigated the reasons for referral of older Australians aged 70 years and older to dual energy X-ray absorptiometry (DXA). The most common clinical indication was being aged 70 years and older, followed by monitoring for fracture or low bone mineral density (BMD). Compared to males, females were twice as likely to have osteoporotic BMD.

Is there an interaction between socioeconomic status and FRAX 10-year fracture probability determined with and without bone density measures? Data from the Geelong Osteoporosis Study of female cohort.

FRAX(©) evaluates 10-year fracture probabilities and can be calculated with and without bone mineral density (BMD). Low socioeconomic status (SES) may affect BMD, and is associated with increased fracture risk. Clinical risk factors differ by SES; however, it is unknown whether aninteraction exists between SES and FRAX determined with and without the BMD. From the Geelong Osteoporosis Study, we drew 819 females aged ≥50 years. Clinical data were collected during 1993-1997. SES was determined by cross-referencing residential addresses with Australian Bureau of Statistics census data and categorized in quintiles. BMD was measured by dual energy X-ray absorptiometry at the same time as other clinical data were collected. Ten-year fracture probabilities were calculated using FRAX (Australia). Using multivariable regression analyses, we examined whether interactions existed between SES and 10-year probability for hip and any major osteoporotic fracture (MOF) defined by use of FRAX with and without BMD. We observed a trend for a SES * FRAX(no-BMD) interaction term for 10-year hip fracture probability (p = 0.09); however, not for MOF (p = 0.42). In women without prior fracture (n = 518), we observed a significant SES * FRAX(no-BMD) interaction term for hip fracture (p = 0.03) and MOF (p = 0.04). SES does not appear to have an interaction with 10-year fracture probabilities determined by FRAX with and without BMD in women with previous fracture; however, it does appear to exist for those without previous fracture.

Bone density and neuromuscular function in older competitive athletes depend on running distance

UNLABELLED: Individuals who are involved in explosive sport types, such as 100-m sprints and long jump, have greater bone density, leg muscle size, jumping height and grip strength than individuals involved in long-distance running. INTRODUCTION: The purpose of this study is to examine the relationship between different types of physical activity with bone, lean mass and neuromuscular performance in older individuals. METHODS: We examined short- (n = 50), middle- (n = 19) and long-distance (n = 109) athletes at the 15th European Masters Championships in Poznań, Poland. Dual X-ray absorptiometry was used to measure areal bone mineral density (aBMD) and lean tissue mass. Maximal countermovement jump, multiple one-leg hopping and maximal grip force tests were performed. RESULTS: Short-distance athletes showed significantly higher aBMD at the legs, hip, lumbar spine and trunk compared to long-distance athletes (p ≤ 0.0012). Countermovement jump performance, hop force, grip force, leg lean mass and arm lean mass were greater in short-distance athletes (p ≤ 0.027). A similar pattern was seen in middle-distance athletes who typically showed higher aBMD and better neuromuscular performance than long-distance athletes, but lower in magnitude than short-distance athletes. In all athletes, aBMD was the same or higher than the expected age-adjusted population mean at the lumbar spine, hip and whole body. This effect was greater in the short- and middle-distance athletes. CONCLUSIONS: The stepwise relation between short-, middle- and long-distance athletes on bone suggests that the higher-impact loading protocols in short-distance disciplines are more effective in promoting aBMD. The regional effect on bone, with the differences between the groups being most marked at load-bearing regions (legs, hip, spine and trunk) rather than non-load-bearing regions, is further evidence in support of the idea that bone adaptation to exercise is dependent upon the local loading environment, rather than as part of a systemic effect.

Menstrual dysfunction and bone health in female athletes

Female athletes are generally considered to be at Iow risk of osteoporosis because of the skeletal loading associated with sports participation. Sites that are exposed to long-term high-impact loading are consistently reported to be higher than the same sites in their sedentary peers. However, weight-bearing exercise does not always ensure that athletes will have high bone-mineral density, as the hormonal environment, dietary factors, and loading history all influence bone-mineral density, In particular, menstrual dysfunction, which can occur with intense training or disordered eating, is a significant risk factor for Iow bone-mineral density. Exercise history before menstrual dysfunction is likely to offer some protection for Iow bone-mineral density, particularly at the hip, Resumption of menses is unlikely to restore bone-mineral density to levels reported in eumenorrheic athletes or even sedentary peers, Athletes at risk of amenorrhea should be identified and their training loads and energy intakes monitored to ensure normal menstrual function, Athletes who remain amenorrheic should be counseled about the possible negative effects of amenorrhea and monitored for bone loss. Early intervention is recommended for amenorrheic athletes with Iow bone-mineral density.

Does high-intensity resistance training maintain bone mass during moderate weight loss in older overweight adults with type 2 diabetes?

The aim was to investigate whether the addition of supervised high intensity progressive resistance training to a moderate weight loss program (RT+WLoss) could maintain bone mineral density (BMD) and lean mass compared to moderate weight loss (WLoss) alone in older overweight adults with type 2 diabetes. We also investigated whether any benefits derived from a supervised RT program could be sustained through an additional home-based program. This was a 12-month trial in which 36 sedentary, overweight adults aged 60 to 80 years with type 2 diabetes were randomized to either a supervised gymnasium-based RT+WLoss or WLoss program for 6 months (phase 1). Thereafter, all participants completed an additional 6-month home-based training without further dietary modification (phase 2). Total body and regional BMD and bone mineral content (BMC), fat mass (FM) and lean mass (LM) were assessed by DXA every 6 months. Diet, muscle strength (1-RM) and serum total testosterone, estradiol, SHBG, insulin and IGF-1 were measured every 3 months. No between group differences were detected for changes in any of the hormonal parameters at any measurement point. In phase 1, after 6 months of gymnasium-based training, weight and FM decreased similarly in both groups (P<0.01), but LM tended to increase in the RT+WLoss (n=16) relative to the WLoss (n=13) group [net difference (95% CI), 1.8% (0.2, 3.5), P<0.05]. Total body BMD and BMC remained unchanged in the RT+WLoss group, but decreased by 0.9 and 1.5%, respectively, in the WLoss group (interaction, P<0.05). Similar, though non-significant, changes were detected at the femoral neck and lumbar spine (L2-L4). In phase 2, after a further 6 months of home-based training, weight and FM increased significantly in both the RT+WLoss (n=14) and WLoss (n=12) group, but there were no significant changes in LM or total body or regional BMD or BMC in either group from 6 to 12 months. These results indicate that in older, overweight adults with type 2 diabetes, dietary modification should be combined with progressive resistance training to optimize the effects on body composition without having a negative effect on bone health.

Use of calcium or calcuim in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis

Background:  Whether calcium supplementation can reduce osteoporotic fractures is uncertain. We did a meta-analysis to include all the randomised trials in which calcium, or calcium in combination with vitamin D, was used to prevent fracture and osteoporotic bone loss.

Methods:  We identified 29 randomised trials (n=63 897) using electronic databases, supplemented by a hand-search of reference lists, review articles, and conference abstracts. All randomised trials that recruited people aged 50 years or older were eligible. The main outcomes were fractures of all types and percentage change of bone-mineral density from baseline. Data were pooled by use of a random-effect model.

Findings:  In trials that reported fracture as an outcome (17 trials, n=52 625), treatment was associated with a 12% risk reduction in fractures of all types (risk ratio 0·88, 95% CI 0·83–0·95; p=0·0004). In trials that reported bone-mineral density as an outcome (23 trials, n=41 419), the treatment was associated with a reduced rate of bone loss of 0·54% (0·35–0·73; p<0·0001) at the hip and 1·19% (0·76–1·61%; p<0·0001) in the spine. The fracture risk reduction was significantly greater (24%) in trials in which the compliance rate was high (p<0·0001). The treatment effect was better with calcium doses of 1200 mg or more than with doses less than 1200 mg (0·80 vs 0·94; p=0·006), and with vitamin D doses of 800 IU or more than with doses less than 800 IU (0·84 vs 0·87; p=0·03).

Interpretation:  Evidence supports the use of calcium, or calcium in combination with vitamin D supplementation, in the preventive treatment of osteoporosis in people aged 50 years or older. For best therapeutic effect, we recommend minimum doses of 1200 mg of calcium, and 800 IU of vitamin D (for combined calcium plus vitamin D supplementation).

Effects of long-term tennis playing on the muscle-bone relationship in the dominant and non-dominant forearms

The relationship between muscle strength and bone mineral density illustrates the positive effect of mechanical loading on bone. But local and systemic factors may affect both muscle and bone tissues. This study investigated the effects of long-term tennis playing on the relationship between lean tissue mass and bone mineral content in the forearms, taking the body dimensions into account. Fifty-two tennis players (age 24.2 +/- 5.8 yrs, 16.2 +/- 6.1 yrs of practice) were recruited. Lean tissue mass (LTM), bone area, bone mineral content (BMC), and bone mineral density were measured at the forearms from a DXA whole-body scan. Grip strength was assessed with a dynamometer. A marked side-to-side difference (p < 0.0001) was found in favor of the dominant forearm in all parameters. Bone area and BMC correlated with grip strength on both sides (r = 0.81 - 0.84, p < 0.0001). The correlations were still significant after adjusting for whole-body BMC body height, or forearm length. This result reinforced the putative role of the muscles in the mechanical loading on bones. In addition, forearm BMC adjusted to LTM or grip strength was higher on the dominant side, suggesting that tennis playing exerts a direct effect on bone.

Cortical and trabecular bone at the forearm show different adaptation patterns in response to tennis playing

Bone responds to impact-loading activity by increasing its size and/or density. The aim of this study was to compare the magnitude and modality of the bone response between cortical and trabecular bone in the forearms of tennis players. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the ulna and radius were measured by dual-energy X-ray absorptiometry (DXA) in 57 players (24.5 ± 5.7 yr old), at three sites: the ultradistal region (50% trabecular bone), the mid-distal regions, and third-distal (mainly cortical bone). At the ultradistal radius, the side-to-side difference in BMD was larger than in bone area (8.4 ± 5.2% and 4.9 ± 4.0%, respectively, p < 0.01). In the cortical sites, the asymmetry was lower (p < 0.01) in BMD than in bone area (mid-distal radius: 4.0 ± 4.3% vs 11.7 ± 6.8%; third-distal radius: 5.0 ± 4.8% vs 8.4 ± 6.2%). The asymmetry in bone area explained 33% of the variance of the asymmetry in BMC at the ultradistal radius, 66% at the mid-distal radius, and 53% at the third-distal radius. The ulna displayed similar results. Cortical and trabecular bone seem to respond differently to mechanical loading. The first one mainly increases its size, whereas the second one preferentially increases its density.

Short-term and long-term site-specific effects of tennis playing on trabecular and cortical bone at the distal radius

Mechanical loading during growth magnifies the normal increase in bone diameter occurring in long bone shafts, but the response to loading in long bone ends remains unclear. The aim of the study was to investigate the effects of tennis playing during growth at the distal radius, comparing the bone response at trabecular and cortical skeletal sites. The influence of training duration was examined by studying bone response in short-term (children) and long-term (young adults) perspectives. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the radius were measured by DXA in 28 young (11.6 ± 1.4 years old) and 47 adult tennis players (22.3 ± 2.7 years old), and 70 age-matched controls (12 children, 58 adults) at three sites: the ultradistal region (trabecular), the mid-distal region, and the third-distal region (cortical). At the ultradistal radius, young and adult tennis players displayed similar side-to-side differences, the asymmetry in BMC reaching 16.3% and 13.8%, respectively (P < 0.0001). At the mid- and third-distal radius, the asymmetry was much greater in adults than in children (P < 0.0001) for all the bone parameters (mid-distal radius, +6.6% versus +15.6%; third-distal radius, +6.9% versus +13.3%, for BMC). Epiphyseal bone enduring longitudinal growth showed a great capacity to respond to mechanical loading in children. Prolonging tennis playing into adulthood was associated with further increase in bone mineralization at diaphyseal skeletal sites. These findings illustrate the benefits of practicing impact-loading sports during growth and maintaining physical activity into adulthood to enhance bone mass accrual and prevent fractures later in life.

Obstacles in the optimization of bone health outcomes in the female athlete triad

Maintaining low body weight for the sake of performance and aesthetic purposes is a common feature among young girls and women who exercise on a regular basis, including elite, college and high-school athletes, members of fitness centres, and recreational exercisers. High energy expenditure without adequate compensation in energy intake leads to an energy deficiency, which may ultimately affect reproductive function and bone health. The combination of low energy availability, menstrual disturbances and low bone mineral density is referred to as the ‘female athlete triad’. Not all athletes seek medical assistance in response to the absence of menstruation for 3 or more months as some believe that long-term amenorrhoea is not harmful. Indeed, many women may not seek medical attention until they sustain a stress fracture.
This review investigates current issues, controversies and strategies in the clinical management of bone health concerns related to the female athlete triad. Current recommendations focus on either increasing energy intake or decreasing energy expenditure, as this approach remains the most efficient strategy to prevent further bone health complications. However, convincing the athlete to increase energy availability can be extremely challenging.
Oral contraceptive therapy seems to be a common strategy chosen by many physicians to address bone health issues in young women with amenorrhoea, although there is little evidence that this strategy improves bone mineral density in this population. Assessment of bone health itself is difficult due to the limitations of dual-energy X-ray absorptiometry (DXA) to estimate bone strength. Understanding how bone strength is affected by low energy availability, weight gain and resumption of menses requires further investigations using 3-dimensional bone imaging techniques in order to improve the clinical management of the female athlete triad.

Reference ranges for bone densitometers adopted Australia-wide : Geelong Osteoporosis Study

Bone densitometry reports a measure of fracture risk in comparison with young adults (T-scores) and age-matched peers (Z-scores). To date, each manufacturer has provided its own reference range resulting in lack of uniformity. The Australia and New Zealand Bone and Mineral Society and Osteoporosis Australia have recognized the need to standardize the reference range and have recommended that data generated by the Geelong Osteoporosis Study (GOS) be used Australia-wide. The GOS recruited a random, population-based sample of adult women and measured bone mineral density (BMD) at the proximal femur and spine using a Lunar DPX-L. These data were used to establish reference ranges for Lunar machines and, using conversion equations, for Norland and Hologic machines. The new standardized Australian reference ranges for BMD will enable consistent diagnosis of osteoporosis and categorization of fracture risk across different types of densitometers.