Role of sport and exercise in the maintenance of female bone health

One-year changes in bone mineral density and bone turnover markers in premenopausal amateur runners: a prospective study

A prospective study was conducted to clarify the 1-year changes in lumbar spine and hip bone mineral density (BMD) and bone turnover markers in premenopausal amateur runners and to determine whether jumping and muscle-strengthening exercises have additive effects on the bone parameters in these runners. Thirty-six premenopausal amateur runners were recruited and were divided into the following two groups: a jumping plus muscle-strengthening exercise group (n =21) and a control group (n =15). All participants continued their running practice for 1 year, and the lumbar spine and total hip BMD and bone turnover markers were monitored. For all participants, the lumbar spine and total hip BMD increased modestly after 1 year (1.31% and 1.54%, respectively) in addition to increases in the bone-specific alkaline phosphatase, osteocalcin, and tartrate-resistant acid phosphatase 5b levels (13.2%-27.8%), indicating mild effects of running activity on bone turnover and BMD at clinically relevant skeletal sites. Jumping plus muscle-strengthening exercises did not significantly influence any bone parameters; however, it was difficult to draw definite conclusions because compliance was poor. These results suggest that long-distance running at the recreational level may be useful in maintaining bone health in premenopausal women.

trans-10,cis-12 CLA promotes osteoblastogenesis via SMAD mediated mechanism in bone marrow mesenchymal stem cells

The inverse relationship between osteoblast and adipocyte differentiation in bone marrow mesenchymal stem cells has been linked to overall bone mass. It has previously been reported that conjugated linoleic acid (CLA) inhibits adipogenesis via a peroxisome-proliferator activated receptor-γ (PPARγ) mediated mechanism, while it increases osteoblastogenesis via a PPARγ-independent mechanism in mesenchymal stem cells. This suggests potential implication of CLA on improving bone mass. Thus the purpose of this study was to determine involvement of CLA on regulation of osteoblastogenesis in murine mesenchymal stem cells by focusing on the Mothers against decapentaplegic (MAD)-related family of molecules 8 (SMAD8), one of key regulators of osteoblastogenesis. The trans-10,cis-12 CLA, but not the cis-9,trans-11, significantly increased osteoblastogenesis via SMAD8, and inhibited adipogenesis independent of SMAD8, while inhibiting factors regulating osteoclastogenesis in this model. These suggest that CLA may help improve osteoblastogenesis via a SMAD8 mediated mechanism.

Health-related predictors of falls and fractures in women over 40

SUMMARY

A longitudinal study of women aged 40-80 predicted single falls from a previous fall history and deficient vestibular integration. Multiple falls were predicted by a fall history, low activity levels, more medical conditions and deficient vestibular integration. Low bone mineral density, more medical conditions and fall history predicted fractures.

INTRODUCTION

The purpose of this study was to identify potentially modifiable health-related factors predicting falls and fractures, focussing on women over 40.

METHODS

Four hundred and forty-nine women aged 40-80 years from the Longitudinal Assessment of Women study participated. Demographic information (age, BMI, medications, medical conditions and activity level), balance assessments (including timed up & go and modified clinical test for sensory interaction of balance) and measurements of bone mineral density and body composition were collected in 2001; fall and fracture data were gathered in 2003, 2005, 2007, 2008 and 2010 to determine incidence.

RESULTS

Multinomial logistic regression revealed that single falls could be predicted by a history of previous falls (OR 3.08) and being unsteady in bipedal stance on foam with eyes closed (OR 1.99). Multiple falls were predicted by a history of falls at baseline (OR 4.69), low levels of activity (OR 2.17), greater number of medical conditions (OR 1.12) and being unsteady in bipedal stance on foam with eyes closed (OR 4.21). Low bone mineral density (OR 3.13), greater number of medical conditions (OR 1.32) and a history of falls (OR 3.04) were predictive of fractures.

CONCLUSIONS

Poor health, decreased balance, and inactivity are predictive of falls and low bone mineral density, low activity level and poor health predictive fractures. Results suggest failing the balance test bipedal stance on foam with eyes closed in the presence of low activity and poor health is a valid quick screening tool for detecting potential fallers for referral for in-depth balance assessment and intervention.

Seven years' experience with etidronate in a woman with anorexia nervosa and vertebral fractures

We report the case of a 30-year-old Japanese woman with anorexia nervosa and vertebral fractures who was treated with etidronate. She had a history of anorexia nervosa, chronic back pain, osteoporosis, and multiple vertebral fractures (morphometric fractures) that responded poorly to treatment with alfacalcidol (1 μg daily) for 1 year and was treated with cyclical etidronate (200 mg for 2 weeks every 3 months) for 7 years. The lumbar spine bone mineral density (BMD) increased, and the serum alkaline phosphatase and urinary cross-linked N-terminal telopeptides of type I collagen levels and back pain decreased. During the 7-year period of treatment with etidronate, no osteoporotic fractures occurred. The patient experienced neither renal dysfunction nor hyperparathyroidism caused by osteomalacia. No gastrointestinal tract symptoms were observed. Thus, etidronate was effective for increasing the lumbar spine BMD and reducing back pain over a 7-year period without causing either osteoporotic fractures or adverse events.

The relation between 25-hydroxyvitamin D with peak bone mineral density and body composition in healthy young adults

OBJECTIVE

The associations between peak bone mineral density (BMD) and body composition with 25 hydroxyvitamin D (25OHD) levels in healthy young adults were evaluated.

METHODS

The number of participants was 464; 347 women and 117 men. The mean age was 24.3 years (range 17-31 years). BMD of the lumbar spine, total body and femoral neck (FN) and body composition were measured by dual energy X-ray absorptiometry. Volumetric BMD, bone mineral apparent density (BMAD), of the lumbar spine and FN was calculated.

RESULTS

In females, 25OHD level was positively associated with FN BMD and BMAD (both p<0.01) and negatively with percentage body fat (p<0.001). In males, 25OHD levels had a positive association with total body BMD and lean body mass (p=0.03 and p=0.01).

CONCLUSIONS

25OHD level is a determinant of peak BMD in both sexes. Vitamin D status was associated with body fat in females and with lean body mass in males.