Physical activity in the prevention and amelioration of osteoporosis in women : interaction of mechanical, hormonal and dietary factors

The pathophysiology, diagnosis, and management of foot stress fractures

INTRODUCTION

There is an increasing prevalence of osteoporosis, and with it a rise in the diagnosis of stress fractures. Postmenopausal women are particularly at risk of stress fractures. This review article describes the pathophysiology of foot stress fractures and the latest diagnostic and treatment strategies for these common injuries.

DISCUSSION

There are numerous risk factors for stress fractures that have been identified in the literature. Reduced bone mineral density is an independent risk factor for delayed union. Prevention of stress fractures with training periodization and nutritional assessment is essential, especially in females. Diagnosis of stress fractures of the foot is based on history and diagnostic imaging, which include radiographs, ultrasound, therapeutic ultrasound, computed tomography, and bone scans; however, magnetic resonance imaging is still the gold standard. Treatment depends on the bone involved and the risk of nonunion, with high-risk fractures requiring immobilization or surgical intervention. Patients presenting with underlying bone mineral deficiency treated without surgery require a longer period of activity modification. Training rehabilitation protocols are described for those with low-risk stress fractures.

RESULTS

A useful algorithm is presented to guide the clinician in the diagnosis and management of such injuries.

Loading dose of physical activity is related to muscle strength and bone density in middle-aged women

The aim of the current study was to investigate the association between loading dose of physical activity, muscle strength and bone density in middle-aged women. Thirty four healthy women (mean age=49.8±7.5years) were recruited. They were requested to wear an accelerometer for a period of 10h (from 9am to 7pm) on a day to record the acceleration. On a separate day their knee extension torque (KET) was measured using an isokinetic dynamometer and broadband ultrasound attenuation (BUA) at the heel by an ultrasound bone scanner. The loading dose of physical activity was calculated at four intensity categories - very light, light, moderate, and vigorous (intensities of <5BW/s, 5-10BW/s, 10-15BW/s and >15BW/s) and for three frequency bands - 0.1-2Hz, 2-4Hz, and 4-6Hz. Correlation analysis was used to examine the association between loading dose and age, KET, and BUA. With the increase of age, there tended to be a decrease in the loading dose of vigorous activity in 2-4 and 4-6Hz frequency bands (Kendall's tau=-.22, p<.1). The increase of loading dose in all three frequency bands in moderate or vigorous activity was associated with higher BUA (Kendall's tau=.27-.41, p<.05). The increase of loading dose in all frequency bands in light, moderate, or vigorous activity was associated with higher KET (Kendall's tau=.30-.45, p<.05). It is concluded that physical activity, especially that at high intensity level and high frequency range, may have beneficial effect on muscle strength and bone density in middle-aged women.

Cardiorespiratory Fitness and Hip Bone Mineral Density in Women: A 6-Year Prospective Study

Cross-sectional studies and short term interventions focusing on fitness and bone mineral density (BMD) are common. However, few investigations have studied the effect of fitness on BMD over an extended period of time. The present study was conducted to determine the extent to which cardiorespiratory fitness influences risk of BMD loss at the hip over 6 yr. A prospective cohort design was used with 245 healthy, middle-aged women. Hip BMD was assessed using dual energy x-ray absorptiometry. Calcium and vitamin D were measured using the Block Food Frequency Questionnaire. Menopause status was measured by a questionnaire. Results showed that fit and unfit women experienced similar changes in hip BMD over time. Specifically, unfit women experienced a non-significant 7% increased risk of losing hip BMD compared to their counterparts (RR = 1.07, 95% CI = 0.66, 1.73). Adjusting statistically for differences in age, initial body weight, and hip BMD, weight change, menopause status, calcium and vitamin D intake, and time between assessments had little effect on the relationship. Fitness level did not influence risk of hip BMD loss over time.

Effects of lifestyle exercise on premenopausal bone health: a randomised controlled trial

Osteoporosis, a slowly evolving public health epidemic, often with an insidious presentation is largely preventable but the optimal dimensions of exercise that may be prescribed for enhancing bone-health among premenopausal adults are yet to be elucidated. Hence, the escalating incidence and burden of prevalence of osteoporosis is yet unabated. Considering that exogenous hormones in the form of hormonal contraception are known to modulate bone mass, investigations of their possible influence on the translation of exercise-induced osteogenic stimuli on the mature bone is pertinent. The aim of this study was to examine the effect of specified lifestyle exercise on bone-health of premenopausal women. Premenopausal women (n = 96, mean age: 22.25 ± 3.5 years; mean BMI: 23.43 ± 3.5 kg/m(2)) participated in a 6-month randomised controlled trial involving home-based rest-interspersed bouts of high-impact exercise for the intervention group and sham exercise for the control group. Approximately half (47) of the participants (24-exercise, 23-control) were on hormonal-based contraception while the other half (49: 24-exercise, 25-control) were not on hormonal contraception. The regime led to a significant 3.7 % increase in broadband ultrasound attenuation of exercisers compared to controls; hormonal contraceptive use did not appear to potentiate the osteogenic effects of the lifestyle exercise regime. The research highlights that short, discrete bouts of high-impact exercise may be a potential public health prescription for enhancing premenopausal bone-health regardless of hormonal contraceptive use.

The secretome of the working human skeletal muscle--a promising opportunity to combat the metabolic disaster?

Recent years have provided clear evidence for the skeletal muscle as an endocrine organ. Muscle contraction during physical activity has emerged as an important activator of the release of the proteins and peptides called "myokines." Diverse proteomic profiling approaches were applied to rodent and human skeletal muscle cells to characterize the complete secretome, to study the regulation of the secretome during cell differentiation or the release of myokines upon contractile activity of myotubes. Several of the exercise-regulated factors have the potency to mediate an interorgan crosstalk. The paracrine function of the secreted peptides and proteins to regulate muscle regeneration, tissue remodeling, and trainability can have direct effects on whole-body glucose disposal and oxygen consumption. The overall composition and dynamic of the myokinome are still incompletely characterized. Recent advantages in metabolomics and lipidomics will add metabolites and lipids with autocrine, paracrine, or endocrine function to the contraction-induced secretome of the skeletal muscle. The identification of these metabolites will lead to a more comprehensive view described by a new myo(metabo)kinome consisting of peptides, proteins, and metabolites.

Osteoporosis and multiple sclerosis: risk factors, pathophysiology, and therapeutic interventions

Multiple sclerosis (MS) is a chronic inflammatory-demyelinating disease of the nervous system. There has been mounting evidence showing that MS is associated with increased risk of osteoporosis and fractures. The development of osteoporosis in MS patients can be related to the cumulative effects of various factors. This review summarizes the common risk factors and physiologic pathways that play a role in development of osteoporosis in MS patients. Physical inactivity and reduced mechanical load on the bones (offsetting gravity) is likely the major contributing factor for osteoporosis in MS. Additional possible factors leading to reduced bone mass are low vitamin D levels, and use of medications such as glucocorticoids and anticonvulsants. The role of the inflammatory processes related to the underlying disease is considered in the context of the complex bone metabolism. The known effect of different MS disease-modifying therapies on bone health is limited. An algorithm for diagnosis and management of osteoporosis in MS is proposed.

Musculoskeletal disorders in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by airway obstruction and inflammation but also accompanied by several extrapulmonary consequences, such as skeletal muscle weakness and osteoporosis. Skeletal muscle weakness is of major concern, since it leads to poor functional capacity, impaired health status, increased healthcare utilization, and even mortality, independently of lung function. Osteoporosis leads to fractures and is associated with increased mortality, functional decline, loss of quality of life, and need for institutionalization. Therefore, the presence of the combination of these comorbidities will have a negative impact on daily life in patients with COPD. In this review, we will focus on these two comorbidities, their prevalence in COPD, combined risk factors, and pathogenesis. We will try to prove the clustering of these comorbidities and discuss possible preventive or therapeutic strategies.

Influence of nutrition and lifestyle on bone mineral density in children from adoptive and biological families

Background

The precise contributions of hereditary and environmental factors to bone density are not known. We compared lifestyle predictors of bone density among adopted and biological children.

Methods

The study comprised 18 adopted children (mean [SD] age, 14.0 [4.1] years) with their non-biological parents and 17 children with their biological parents. Bone mineral density (BMD; g/cm²) was measured at the lumbar spine, total femur, and distal radius. Nutritional intake was assessed by food frequency questionnaire. Information on smoking and physical activity was obtained by questionnaire.

Results

Intakes of all nutrients, corrected for energy intake, and all lifestyle characteristics except sleep duration were similar in biological children and their parents. As compared with their parents, adopted children had significantly different energy, protein, and calcium intakes and physical activity levels. In a regression model, BMD z scores of adopted children and their parents were significantly inversely associated at the spine and total femur, whereas BMD z scores of biological children and their parents were significantly positively associated at all measurement sites. The greatest proportion of total variance in BMD was accounted for by calcium intake among adopted children and by parental BMD among biological children.

Conclusions

For some lifestyle characteristics and nutrient intakes, the differences between parents and children were more obvious among adoptive families than among biological families. The most important lifestyle predictor of bone density was calcium intake.

Young male soccer players exhibit additional bone mineral acquisition during the peripubertal period: 1-year longitudinal study

The aim of this study was to determine whether soccer could have different bone benefits in prepubescent and pubescent boys. We investigated 76 boys aged 10 to 13 years during a 1-year study. All boys were prepubescent at the beginning of the study (T0); pubescent status was determined by a complete 24-h urine hormonal assay of FSH-LH, with LH ≤ 0.31 IU/24 h and FSH ≤ 2.19 IU/24 h corresponding to prepubescent Tanner stage I and with 0.31 < LH < 0.95 IU/24 h and 1.57 < FSH < 3.77 IU/24 h corresponding to pubescent Tanner stage II. At the end of the study (T1), 35 boys remained prepubescent (22 soccer players (F1) and 13 controls (C1)), and 41 boys had entered puberty (26 soccer players (F2) and 15 controls (C2)). Soccer players completed 2 to 5 h of training plus one competition game per week during the school year, and controls only had physical education at school. Bone mineral content (BMC) was measured at T0 and T1 by DPX in the lumbar spine, total hip, and whole body (WB) for a comparison between soccer players and controls. At T0, no BMC difference was found between F1 and C1, but BMC was higher in F2 than C2 in WB and weight-bearing sites. At T1, BMC was higher in WB and weight-bearing sites in both F1 and F2 compared to their respective controls. Between T0 and T1, soccer induced a BMC gain at weight-bearing sites in both F1 and F2 compared to C1 and C2, respectively. The soccer-related bone gain was greater in WB and weight-bearing (the lumbar spine, total hip, and supporting leg) and non-weight-bearing bones (dominant arm and nondominant arm) in boys who became pubescent than in boys who remained prepubescent. In conclusion, 1-year study in young male soccer players demonstrates that the process of bone accretion at the very early phase of puberty is more intensely stimulated by the combination of physical exercise and sexual impregnation than by one of these factors alone.

Comparison of Bone Mineral Density among Alcoholism and Nonalcoholism Athlete and Nonathlete Subjects

BACKGROUND

The aim of this study was to compare bone mineral density among alcoholic, nonalcoholic and nonathlete subjects.

MATERIALS AND METHODS

The group consisted of physically active people. A questionnaire was given to both alcoholics and nonalcoholics and 28 persons were randomly selected (15 members who consumed alcohol and 13 who did not). In order to collect the data on mineral aggregation, a testing device (DEXA) was used. The data were analyzed using SPSS software.

RESULTS

It was found that higher bone aggregation in each of the two athletic group in comparison with the nonathletic group (p < 0.05).

CONCLUSION

Exercise may have a positive impact on bone mineral density.

ABBREVIATIONS

BMD: bone mineral density; SPSS: Statistical package for social science.How to cite this article: Hosseini S, Valizade R, Heydarabadi FD. Comparison of Bone Mineral Density among Alcoholism and Nonalcoholism Athlete and Nonathlete Subjects. Euroasian J Hepato-Gastroenterol 2014;4(1):1-3.

Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis

Background. Growth hormone (GH) and insulin-like growth factor (IGF-1) are fundamental in skeletal growth during puberty and bone health throughout life. GH increases tissue formation by acting directly and indirectly on target cells; IGF-1 is a critical mediator of bone growth. Clinical studies reporting the use of GH and IGF-1 in osteoporosis and fracture healing are outlined. Methods. A Pubmed search revealed 39 clinical studies reporting the effects of GH and IGF-1 administration on bone metabolism in osteopenic and osteoporotic human subjects and on bone healing in operated patients with normal GH secretion. Eighteen clinical studies considered the effect with GH treatment, fourteen studies reported the clinical effects with IGF-1 administration, and seven related to the GH/IGF-1 effect on bone healing. Results. Both GH and IGF-1 administration significantly increased bone resorption and bone formation in the most studies. GH/IGF-1 administration in patients with hip or tibial fractures resulted in increased bone healing, rapid clinical improvements. Some conflicting results were evidenced. Conclusions. GH and IGF-1 therapy has a significant anabolic effect. GH administration for the treatment of osteoporosis and bone fractures may greatly improve clinical outcome. GH interacts with sex steroids in the anabolic process. GH resistance process is considered.

Effects of short-term resistance training and pulsed electromagnetic fields on bone metabolism and joint function in severe haemophilia A patients with osteoporosis: a randomized controlled trial

OBJECTIVES

To assess the effects of short-term resistance training and pulsed electromagnetic fields on bone metabolism and joint function in patients with haemophilia with osteoporosis.

DESIGN

A randomized, controlled, patient and blood sample assessor-blinded, six-week trial, three times weekly.

SETTING

Hospital outpatients with severe haemophilia A and osteoporosis.

SUBJECTS

Forty-eight patients were randomly assigned to resistance training (RT, n = 13), combined resistance training with pulsed electromagnetic fields (RTPEMF, n = 12), pulsed electromagnetic fields (PEMF, n = 11) and control (n = 12) groups.

INTERVENTION

The RT group received 30-40 minutes of resistance exercises and placebo pulsed electromagnetic fields. The RTPEMF group received the same exercises with lower repetition and 30 minutes of pulsed electromagnetic fields. The PEMF group was exposed to 60 minutes of pulsed electromagnetic fields (30 Hz and 40 Gauss).

MAIN MEASURES

Bone-specific alkaline phosphatase, N-terminal telopeptide of type 1 collagen, and joint function, using the modified Colorado Questionnaire, were measured before and after the programme.

RESULTS

The absolute change of bone-specific alkaline phosphatase was significant in the RT and RTPEMF groups compared with the control group (25.41 ± 14.40, 15.09 ± 5.51, and -4.73 ± 2.93 U/L, respectively). The absolute changes in the total score for joint function were significant for knees, ankles, and elbows in the RT group (9.2 ± 1.38, 5.1 ± 0.5, and 3.2 ± 0.8, respectively) and the RTPEMF group (7.7 ± 1.0, 3.3 ± 0.6, and 2.5 ± 0.7, respectively) compared to the PEMF and control groups. This value was significant for knee joints in the PEMF group compared to the control group (3.4 ± 0.5 and 0.66 ± 0.4, respectively).

CONCLUSIONS

Resistance training is effective for improving bone formation and joint function in severe haemophilia A patients with osteoporosis.

The effect of physical exercise on bone density in middle-aged and older men: a systematic review

Although trials have shown that exercise has positive effects on bone mineral density (BMD), the majority of exercise trials have been conducted in older women. The aim of this study was to systematically review trials examining the effect of weight-bearing and resistance-based exercise modalities on the BMD of hip and lumbar spine of middle-aged and older men. Eight electronic databases were searched in August 2012. Randomised controlled or controlled trials that assessed the effect of weight-bearing and resistance-based exercise interventions on BMD measured by dual-energy x-ray absorptiometry, and reported effects in middle-aged and older men were included. Eight trials detailed in nine papers were included. The interventions included walking (n = 2), resistance training (n = 3), walking + resistance training (n = 1), resistance training + impact-loading activities (n = 1) and resistance training + Tai Chi (n = 1). Five of the eight trials achieved a score of less than 50% on the modified Delphi quality rating scale. Further, there was heterogeneity in the type, intensity, frequency and duration of the exercise regimens. Effects of exercise varied greatly among studies, with six interventions having a positive effect on BMD and two interventions having no significant effect. It appears that resistance training alone or in combination with impact-loading activities are most osteogenic for this population, whereas the walking trials had limited effect on BMD. Therefore, regular resistance training and impact-loading activities should be considered as a strategy to prevent osteoporosis in middle-aged and older men. High quality randomised controlled trials are needed to establish the optimal exercise prescription.

Body composition and reproductive function exert unique influences on indices of bone health in exercising women

Reproductive function, metabolic hormones, and lean mass have been observed to influence bone metabolism and bone mass. It is unclear, however, if reproductive, metabolic and body composition factors play unique roles in the clinical measures of areal bone mineral density (aBMD) and bone geometry in exercising women. This study compares lumbar spine bone mineral apparent density (BMAD) and estimates of femoral neck cross-sectional moment of inertia (CSMI) and cross-sectional area (CSA) between exercising ovulatory (Ov) and amenorrheic (Amen) women. It also explores the respective roles of reproductive function, metabolic status, and body composition on aBMD, lumbar spine BMAD and femoral neck CSMI and CSA, which are surrogate measures of bone strength. Among exercising women aged 18-30 years, body composition, aBMD, and estimates of femoral neck CSMI and CSA were assessed by dual-energy x-ray absorptiometry. Lumbar spine BMAD was calculated from bone mineral content and area. Estrone-1-glucuronide (E1G) and pregnanediol glucuronide were measured in daily urine samples collected for one cycle or monitoring period. Fasting blood samples were collected for measurement of leptin and total triiodothyronine. Ov (n = 37) and Amen (n = 45) women aged 22.3 ± 0.5 years did not differ in body mass, body mass index, and lean mass; however, Ov women had significantly higher percent body fat than Amen women. Lumbar spine aBMD and BMAD were significantly lower in Amen women compared to Ov women (p < 0.001); however, femoral neck CSA and CSMI were not different between groups. E1G cycle mean and age of menarche were the strongest predictors of lumbar spine aBMD and BMAD, together explaining 25.5% and 22.7% of the variance, respectively. Lean mass was the strongest predictor of total hip and femoral neck aBMD as well as femoral neck CSMI and CSA, explaining 8.5-34.8% of the variance. Upon consideration of several potential osteogenic stimuli, reproductive function appears to play a key role in bone mass at a site composed of primarily trabecular bone. However, lean mass is one of the most influential predictors of bone mass and bone geometry at weight-bearing sites, such as the hip.

Bone mineral density, quantitative ultrasound parameters and bone metabolism in postmenopausal women with depression

Low bone mineral density, which increases the risk of stress fragility fractures, is a frequent, often persistent finding in patients with major depressive disorder (MDD). The clinical association between major depressive disorder and osteopenia is still unclear, although several factors are associated with a loss of bone mass. The aim of our study, therefore, was to evaluate bone mineral density and bone metabolism in patients with MDD. Bone mineral density was evaluated in fifty postmenopausal women with MDD, and in 50 matched postmenopausal control women by dual-energy X-ray absorptiometry of the lumbar spine and femur, and by ultrasonography of the calcaneus and phalanges. Serum levels of 25-hydroxivitamin D, parathyroid hormone, Osteoprotegerin/Receptor Activator for Nuclear Factor κB Ligand ratio, bone turnover markers, serum and urinary cortisol were examined. Bone mineral density of the lumbar spine (BMD: 0.72 ± 0.06 vs. 0.82 ± 0.09 g/cm(2), p < 0.001), femoral neck (BMD: 0.58 ± 0.04 vs. 0.71 ± 0.07 g/cm(2), p < 0.001) and total femur (BMD 0.66 ± 0.09 vs. 0.54 ± 0.06 g/cm(2), p < 0.001); and ultrasound parameters at calcaneus (SI: 81.30 ± 6.10 vs. 93.80 ± 7.10, p < 0.001) and phalanges (AD-SOS: 1915.00 ± 37.70 vs. 2020.88 ± 39.46, p < 0.001; BTT : 1.30 ± 0.8 vs. 1.45 ± 0.9, p < 0.001) are significantly lower in patients with MDD compared with controls. Moreover bone turnover markers, parathyroid hormone levels and Receptor Activator for Nuclear Factor κB Ligand are significantly higher in MDD patients compared with controls, while serum levels of 25-hydroxivitamin D and osteoprotegerin are significantly lower. There are no differences in urinary excretion and serum cortisol between groups. Postmenopausal women with depressive disorder have an elevated risk for osteoporosis. Our data suggest that a high level of parathyroid hormone may play a role in the pathogenetic process underlying osteopenia in these patients.

Bone remodelling biomarkers after whole body cryotherapy (WBC) in elite rugby players

Whole body cryotherapy (WBC) consists of a brief exposure to extreme cold air (-110°C) in a controlled chamber and it is applied in sports medicine to improve recovery from musculoskeletal trauma. The aim of this study is to better define the beneficial effect of WCB on the musculoskeletal system of athletes, in particular on bone remodelling. Remodelling osteoimmunological biomarkers OPG, RANKL and RANK were measured after WBC treatment in 10 male rugby players randomly selected from the Italian National team. OPG levels were increased significantly, supporting the view that WBC induces an osteogenic effect. Further studies evaluating the effect of WBC on bone metabolism are desirable.

Relationship of knowledge about osteoporosis with education level and life habits

AIM: To assess possible relationships of knowledge and related factors with educational level and osteoporosis-related life habits.

METHODS: This was a cross sectional study conducted on 268 women (≥ 35 years old) from June 2011 to August 2011. The sample collection was done in outpatient clinics in three university hospitals in Isfahan, Iran. We used a demographic questionnaire containing questions that evaluated osteoporosis-related life habits, including exercise, smoking, intake of calcium and vitamin D supplements and so on. We also used the Osteoporosis Knowledge Assessment Tool to measure osteoporosis knowledge of women.

RESULTS: The mean level of knowledge about awareness of osteoporosis, its risk factors and preventive factors were 56, 55 and 22, respectively. The relationship of education level and awareness of osteoporosis, its risk factors and preventive factors was significant, with R = 0.76, R = 0.73 and R = 0.83, respectively (P < 0.001). The relationship of education level and osteoporosis-related life habits was not significant (R = 0.03 and P = 0.56). The relationship of osteoporosis-related life habits and awareness of osteoporosis and its risk factors was significant, with R = 16%, P = 0.006 and R = 16%, P = 0.008, respectively, but the relationship of osteoporosis-related life habits and preventive factors was not significant (R = 0, P = 0.99).

CONCLUSION: Iranian women with a higher education level have significantly better knowledge about osteoporosis than women with a lower educational level but they do not use this knowledge in their life.

Exercise-based smoking cessation interventions among women

Although smoking rates are lower among women than men, women are less likely to quit smoking in cessation trials. This is in part due to their tendency to smoke to help prevent or mitigate negative mood/affect, depression and/or postcessation weight gain. Exercise helps to alleviate women's fear of postcessation weight gain and reduces their cessation-related mood symptoms, making it a theoretically ideal smoking cessation intervention for women. In addition, short bouts of exercise decrease cigarette cravings and withdrawal symptoms among temporarily abstinent smokers. However, results from exercise-based smoking cessation interventions to date have been mostly nonsignificant. This paper describes the theoretical mechanisms (psychological, behavioral, physiological and neurobiological) and practical reasons underlying our belief that exercise-based smoking cessation interventions should not yet be abandoned despite their current paucity of supporting evidence. It also presents ideas for modifying future exercise-based smoking cessation interventions to increase adherence and, as a result, more accurately evaluate the effect of exercise on smoking cessation.

Bone mineral density and bone metabolism in patients with major depressive disorder without somatic comorbidities

BACKGROUND

Major depressive disorder (MDD) has been linked with accelerated bone loss leading to the development of low bone mineral density (BMD). Several mechanisms have been discussed as causative factors, e.g. lifestyle, selective serotonin reuptake inhibitor (SSRI) intake, or the influence of proinflammatory cytokines.

METHODS

In a cross-sectional study of in-patients with a current episode of MDD, without somatic comorbidities, we determined various parameters of bone metabolism, inflammatory parameters and parameters of depression. BMD was measured by dual x-ray absorptiometry.

RESULTS

Of 50 patients, only one had low BMD in any of the measure sites. Body mass index (BMI) correlated positively with Z-scores. 83.3% of the examined patients had elevated osteoprotegerin (OPG) levels. SSRI intake did not have an effect on BMD. BMD in the femoral neck was significantly lower in smokers. We also found a positive correlation between the level of physical activity and osteocalcin levels.

CONCLUSIONS

In our sample, young to middle-aged, somatically healthy, and acutely depressed patients with a history of MDD showed no reduction of BMD. This could be due to compensatory mechanisms, as suggested by elevated OPG levels. Physical activity and high BMI could also have served as protective factors. Still, as patients with MDD often suffer from comorbidities or take medication with a negative effect on bone, this population should be appreciated as a high-risk group for the development of osteopenia and osteoporosis.

Menopause, estrogens and frailty

The controversy surrounding the results from the Women's Health Initiative (WHI) trials published a decade ago caused a significant decline in the use of menopausal hormone replacement therapy. However, these results have been vehemently contested and several lines of evidence suggest that in perimenopausal and non-obese women, estrogen therapy may indeed be of benefit. There is ample proof that menopause causes a loss of musculoskeletal tissue mass and quality, thereby causing a loss of health and quality of life. There is also solid evidence that hormone replacement therapy in itself prevents most of these effects in connective tissue in itself. Besides the independent, direct effects on the musculoskeletal tissues, estrogen deficiency also reduces the ability to adequately respond and adapt to external mechanical and metabolic stressors, e.g. exercise, which are otherwise the main stimuli that should maintain musculoskeletal integrity and metabolic function. Thus, normophysiological estrogen levels appear to exert a permissive effect on musculoskeletal adaptations to loading, thereby likely improving the outcome of rehabilitation following critical illness, musculoskeletal trauma or orthopedic surgical therapy. These effects add to the evidence supporting the use of estrogen therapy, particularly accelerated gain of functional capacity and independence following musculoskeletal disuse.

Two years of growth hormone treatment in adults with Prader-Willi syndrome do not improve the low BMD

BACKGROUND

Bone mineral density (BMD) in adult patients with Prader-Willi syndrome (PWS) might be low due to high bone turnover.

OBJECTIVES

The objective of the study was to investigate bone mass in a group of adult PWS subjects and study the effects of GH treatment on BMD and markers of bone turnover.

DESIGN

Forty-six adults with genetically verified PWS were randomized to GH or placebo for 12 months, followed by open prospective GH for 24 additional months. BMD at the lumbar spine (LS) L1-4, the total hip, and the total body was assessed by dual-energy x-ray absorptiometry at baseline and every 12th month thereafter. Markers of bone turnover were measured at baseline and at the end of the controlled study.

RESULTS

In this cohort of adult subjects with PWS, baseline BMD was reduced in all compartments compared with the reference (Z-scores). Men had lower Z-scores BMD than women in LS and total body (P < .05). With 12 months of GH, LS-BMD was significantly reduced compared with placebo. No changes in BMD were observed with continuous GH treatment for 24 months. The bone formation markers increased with GH therapy compared with placebo, whereas the resorption marker did not change.

CONCLUSIONS

Adult PWS subjects, especially the men, have low bone mass that was not improved with GH treatment for 2 years. Because PWS subjects are short, BMD might be underestimated and should be adjusted for. Further studies, with adequate GH and sex hormone replacement throughout puberty and early adult life, are needed to better characterize PWS.

Physical activity during life course and bone mass: a systematic review of methods and findings from cohort studies with young adults

Background

The purpose of this paper was to review the literature of the cohort studies which evaluated the association between physical activity during the life course and bone mineral content or density in young adults.

Methods

Prospective cohort studies with bone mineral density or content measured in the whole body, lumbar spine and femoral neck by dual energy x-ray absorptiometry as outcome and physical activity as exposure were searched. Two independent reviewers selected studies retrieved from electronic databases (Medline, Lilacs, Web of Science and Scielo) and reviewed references of all selected full text articles. Downs & Black criterion was used in the quality assessment of these studies.

Results

Nineteen manuscripts met inclusion criteria. Lumbar spine was the skeletal site most studied (n = 15). Different questionnaires were used for physical activity evaluation. Peak strain score was also used to evaluate physical activity in 5 manuscripts. Lack of statistical power calculation was the main problem found in the quality assessment. Positive associations between physical activity and bone mass were found more in males than in females; in weight bearing anatomical sites (lumbar spine and femoral neck) than in total body and when physical activity measurements were done from adolescence to adulthood – than when evaluated in only one period. Physical activity during growth period was associated with greater bone mass in males. It was not possible to conduct pooled analyses due to the heterogeneity of the studies, considering mainly the different instruments used for physical activity measurements.

Conclusions

Physical activity seems to be important for bone mass in all periods of life, but especially the growth period should be taking into account due to its important direct effect on bone mass and its influence in physical activity practice in later life. Low participation in peak strain activities may also explain the lower number of associations found in females.

Envelhecimento e dança: análise da produção científica na Biblioteca Virtual de Saúde

O envelhecimento produz perda progressiva das aptidões funcionais e da integração social, e a dança vem contribuir na melhora e/ou manutenção dessas perdas, refletindo positivamente na qualidade de vida dos idosos. Pelo fato de a produção científica ser um processo contínuo que traz a dinâmica da descoberta, contribuindo com a ciência e fortalecendo o ensino e o saber científico, desenvolveu-se esta pesquisa, com o objetivo de realizar uma análise da produção científica sobre a temática dança e o idoso nas bases de dados LILACS, MEDLINE e SciELO acessadas pela Biblioteca Virtual de Saúde (BVS), especificando: tipo de publicação, título, autoria e gênero, estrutura discursiva dos resumos, tipo de pesquisa, estratégias e tipo de análise. Os descritores utilizados foram dança e idoso(s) e dança e envelhecimento. Foram levantados 82 artigos; mas 14 artigos foram excluídos devido a ausência de resumo, totalizando 68 artigos para a análise. Os resultados metacientíficos revelaram que: 92,64% eram artigos; melhor adequação do título quanto ao número de vocábulos; 89,9% publicações de autoria múltipla produzida por ambos os gêneros; estrutura dos resumos adequada; as pesquisas de campo (82,35%), descritivas (57,36%) e a análise quantitativa (45,6%) são as mais utilizadas. Conclui-se que os resumos estão adequados aos parâmetros metacientíficos, exceto pelo título, porém há necessidade de novas pesquisas sobre o tema com delineamentos experimentais baseados em evidências e análises inferências dos resultados para o avanço do conhecimento sobre dança e envelhecimento.

Sarcopenia and its relationship with bone mineral density in middle-aged and elderly European men

The aim of this study was to determine the relationship between reduced muscle mass (sarcopenia) and areal bone mineral density (BMD(a)) in middle-aged and elderly community-dwelling European men. Men with sarcopenia had significantly lower BMD(a) and were more likely to have osteoporosis compared with men without sarcopenia.

INTRODUCTION

In men, the relationship between reduced muscle mass (sarcopenia) and BMD(a) is unclear. This study aimed to determine this relationship in middle-aged and elderly community-dwelling men.

METHODS

Men aged 40-79 years from the Manchester (UK) and Leuven (Belgium) cohorts of the European Male Ageing Study were invited to attend for assessment including dual-energy X-ray absorptiometry, from which appendicular lean mass (aLM), fat mass (FM) and whole-body, spine and hip BMD(a) were determined. Relative appendicular skeletal muscle mass (RASM) was calculated as aLM/height². Muscle strength was assessed in subjects from Leuven. Sarcopenia was defined by RASM at <7.26 kg/m² and by the recent definition of the European Working Group on Sarcopenia in Older People (RASM at <7.26 kg/m(2) plus low muscle function). Linear regression was used to determine the associations between aLM, FM, muscle strength and BMD(a) and logistic regression to determine the association between sarcopenia and osteoporosis.

RESULTS

Six hundred seventy-nine men with a mean age of 59.6 (SD = 10.7), contributed data to the analysis; 11.9 % were sarcopenic by the conventional definition. After adjustment for age and centre, aLM, RASM and FM were positively associated with BMD(a). Men with RASM at <7.26 kg/m² had significantly lower BMD(a) compared with those with RASM at ≥7.26 kg/m(2). In a multivariable model, aLM was most consistently associated with BMD(a). Men with sarcopenia were more likely to have osteoporosis compared with those with normal RASM (odds ratio = 3.0; 95 % CI = 1.6-5.8).

CONCLUSIONS

Sarcopenia is associated with low BMD(a) and osteoporosis in middle-aged and elderly men. Further studies are necessary to assess whether maintaining muscle mass contributes to prevent osteoporosis.

Vitamin C and zinc intakes are related to bone macroarchitectural structure and strength in prepubescent girls

The extent to which nutrient intake may influence bone structure and strength during maximal rates of skeletal growth remains uncertain. We examined the relationship of dietary intake of micronutrients and bone macroarchitectural structure in young girls. This cross-sectional analysis included baseline data from 363 fourth- and sixth-grade girls enrolled in the Jump-In study. Nutrient intake was assessed using the Harvard Youth/Adolescent Food Frequency Questionnaire. Volumetric BMD (vBMD), bone geometry, and strength were measured by peripheral quantitative computed tomography. Correlations and regression modeling assessed relations between usual nutrient intake and bone parameters. In fourth-grade girls, metaphyseal and diaphyseal area and circumferences as well as diaphyseal strength were associated with vitamin C intake (r = 0.15-0.19, p < 0.05). Zinc intake was correlated with diaphyseal vBMD (r = 0.15-0.16, p < 0.05). Using multiple linear regression to adjust for important covariates, we observed significant independent associations for vitamin C and zinc with bone parameters. For every milligram per day of vitamin C intake trabecular area increased by 11 %, cortical strength improved by 14 %, and periosteal and endosteal circumferences increased by 5 and 8.6 %, respectively. For every milligram per day of zinc intake, cortical vBMD increased by <1 %. No significant associations were observed in sixth-grade girls. Results of this study suggests that vitamin C and zinc intake are positively associated with objective measures of bone geometry, size, and strength in fourth-grade girls. This indicates that potential differences in micronutrient and bone associations at various age-associated stages of bone maturation may be indicative of competing hormonal influences.

Relationship between plasminogen activator inhibitor type-1 (PAI-1) gene polymorphisms and osteoporosis in Turkish women

OBJECTIVE

The development of osteoporosis is associated with several risk factors, such as genetic structures that affect bone turnover and bone mass. The impact of genetic structures on osteoporosis is not known. Plasminogen activator inhibitor type-1 regulates the bone matrix and bone balance. This study assessed the correlation between plasminogen activator inhibitor type-1 gene 4G/5G polymorphisms and osteoporosis in a population of Turkish women.

METHODS

A total of 195 postmenopausal female patients who were diagnosed with osteoporosis (Group I) based on bone mineral density measurements via dual-energy x-ray absorptiometry and 90 females with no osteoporosis (Group II) were included in this study. Correlations between PAI-1 gene 4G/5G polymorphisms and osteoporosis were investigated through the identification of PAI-1 gene 4G/5G polymorphism genotypes using the polymerase chain reaction.

RESULTS

No significant differences in the genotype and allele frequency of 4G/5G plasminogen activator inhibitor type-1 polymorphisms were observed between the two groups, and both groups exhibited the most frequently observed 4G5G genotype.

CONCLUSION

No correlation between the development of osteoporosis in the female Turkish population and 4G/5G plasminogen activator inhibitor type-1 gene polymorphisms was observed.

Nutrition and physical activity in health promotion and disease prevention: potential role for the dental profession

Nutrition contributes to many of the leading causes of death in the United States, yet less than one-third of dental students feel competent to discuss the relationship of nutrition and systemic disease with their patients. The American Dental Association policy statements acknowledge a need for health professionals and organizations to provide continuing education to professionals and counseling to patients to combat the growing problems of overweight and obesity. Dentists can play a major role in educating patients to adopt a healthier lifestyle, including nutrition and physical activity recommendations. An understanding of the complexity of behavior change may enhance the dentist's ability to assist their patients in making desired changes.

Bone health: part 2, physical activity

Mechanical loading is a crucial factor for maintaining skeletal health. Physical activities, exercise, and sports provide a wealth and variety of mechanical loads to bones, through muscle forces, ground reaction forces, and other contact or impact forces. Weightbearing activities can be effective exercises to enhance bone health-particularly, those that involve jumping and impact loads (with greater strain magnitudes, rates, and frequencies). Physical activity appears to be acutely beneficial for enhancing bone health in the early pubertal period and in older age, such as in postmenopausal women. In preparing this article, PubMed, Web of Science, and relevant edited books (English language) were reviewed from 1961 to present.

The pathophysiology, diagnosis, and management of stress fractures in postmenopausal women

INTRODUCTION

Increasing numbers of elderly individuals are now participating in marathons. With increased participation in running, there has been an increase in the diagnosis of stress fractures in the elderly population. Postmenopausal women are particularly at risk due to osteoporosis.

DISCUSSION

There are numerous risk factors for stress fractures in the literature that need to be addressed to reduce the risk of injury and recurrence in postmenopausal women. Diagnostic tests include plain radiograph, ultrasound, therapeutic ultrasound, computed tomography scan, and isotope bone scans; however, magnetic resonance imaging remains the gold standard. Treatment is based on risk stratification, with high-risk fractures managed aggressively with either non-weightbearing or surgical intervention. Although exercise is prescribed as a well-recognized treatment modality of poor bone density, balance is essential to avoid precipitating stress fractures.

CONCLUSION

Optimal exercise programs should balance the beneficial effect of increasing bone mineral density through exercise with the detrimental effect of stress fractures. A useful algorithm is presented in this article to guide the clinician in the diagnosis and management of appropriate investigations and management of such injuries. This review article describes the pathophysiology and provides a review of the literature to determine the latest diagnostic and treatment strategies for this unique population.

Physical exercise affects cell proliferation in lumbar intervertebral disc regions in rats

STUDY DESIGN

Descriptive experimental study.

OBJECTIVE

The aim of this study was to investigate the effect of exercise on cell proliferation in different areas of the intervertebral disc (IVD) and recruitment of cells possibly active in regeneration of normal rat lumbar IVDs.

SUMMARY OF BACKGROUND DATA

Little is known about the effects of physical exercise on lumbar IVD tissue. Recently, stem cell niches in the perichondrium area of the IVD were identified and cells in these niches have been suggested to be involved in the normal regeneration of the IVD.

METHODS

Thirty Sprague-Dawley rats were exposed to 5-bromo-2-deoxyuridine (BrdU) diluted in the drinking water during 14 days. Fifteen rats ran on a treadmill daily for 50 min/d, 5 d/wk (exercise group), and 15 nonexercised rats served as controls. Immunohistochemical analyses (anti-BrdU antibody) were performed at 9, 14, 28, 56, and 105 days after the start of the exercise protocol. BrdU positive cells were counted in the stem cell niche area, the peripheral region of epiphyseal cartilage area, and the annulus fibrous outer and inner areas. Data were analyzed by 2-way analysis of variance (significance level; P < 0.05).

RESULTS

The BrdU positive cell numbers in the stem cell niche and annulus fibrous outer regions were increased in discs from the exercising group on days 14 (P < 0.01) and 105 (P < 0.05) and at day 14 (P < 0.01) in the peripheral epiphyseal cartilage region compared with controls.

CONCLUSION

Physical exercise was shown to have positive effects on cell proliferation in IVDs, with involvement of various disc regions, indicating a differential response by disc tissue to exercise depending on anatomical location and tissue characteristics.

Review article: non-alcoholic fatty liver disease and osteoporosis--clinical and molecular crosstalk

BACKGROUND

Low bone mineral density (BMD) has been reported in both paediatric and adult patients with non-alcoholic fatty liver disease (NAFLD). The mechanisms behind the reduced BMD in NAFLD are still not completely understood.

AIM

To provide a critical overview of the pathophysiological pathways linking NAFLD, reduced BMD and osteoporosis, with a special focus on the alterations of soluble mediators which could link fat accumulation in the liver with bone health. The MEDLINE database was searched by a combination of keywords: non-alcoholic fatty liver disease OR hepatic steatosis OR metabolic syndrome OR insulin resistance AND bone mineral density OR osteoporosis OR bone AND biomarkers OR serum marker.

RESULTS

Several factors that may influence bone mineralisation and the increased risk of osteoporosis in NAFLD can be discussed. These include the release of cytokines from the inflamed liver which may influence the bone microenvironment, vitamin D deficiency, and limited physical activity. Circulating markers of bone metabolism, including osteopontin, osteoprotegerin, osteocalcin and fetuin-A, have been found to be altered in patients with NAFLD.

CONCLUSION

A better understanding of the mechanisms that link bone metabolism and the liver may open a new frontier to fight two highly prevalent conditions like NAFLD and osteoporosis.

AST-induced bone loss in men with prostate cancer: exercise as a potential countermeasure

Androgen suppression treatment (AST) for men with prostate cancer is associated with a number of treatment-related side effects including an accelerated rate of bone loss. This loss of bone is greatest within the first year of AST and increases the risk for fracture. Pharmaceutical treatment in the form of bisphosphonates is currently used to counter the effects of hormone suppression on bone but is costly and associated with potential adverse effects. Recently, exercise has been shown to be an important adjuvant therapy to manage a range of treatment-related toxicities and enhance aspects of quality of life for men receiving AST. We propose that physical exercise may also have an important role in not only attenuating the bone loss associated with AST but in improving bone health and reducing fracture risk. In this review, the rationale underlying exercise as a countermeasure to AST-induced bone loss is provided.

[Impact of physical activity and exercise on bone health in the life course : a review]

Physical activity and exercise are important determinants for metabolic and cardiovascular health. They also play an important role for bone health in childhood, adolescence, and adulthood. This review summarizes results from observational and intervention studies which evaluated the association between physical activity/exercise and bone health in different life course stages. In childhood and adolescence, physical activity and exercise induce improved bone accrual. In adulthood, mainly in postmenopausal women, long-term exercise programs reduce age-related bone loss. Especially weight-bearing activities seem to have an important osteogenic effect. Children and adolescent show a higher bone accrual until 5 years after cessation of an exercise program compared to their peers, who do not participate in an exercise program. In contrast, adults who quit exercising have a higher decrease in bone stiffness compared to adults who never exercised. This effect was particularly seen in postmenopausal women. Continuous physical activity and exercise over the life course and the implementation of exercise programs in schools and community-based intervention programs can help prevent or even reduce osteoporosis and osteoporosis-related fractures. Due to the lack of prospective longitudinal studies, the supposed long-term sustainable protective effect of physical activity and exercise in childhood and adolescent on bone health in later adulthood is not well established.

Muscles, exercise and obesity: skeletal muscle as a secretory organ

During the past decade, skeletal muscle has been identified as a secretory organ. Accordingly, we have suggested that cytokines and other peptides that are produced, expressed and released by muscle fibres and exert either autocrine, paracrine or endocrine effects should be classified as myokines. The finding that the muscle secretome consists of several hundred secreted peptides provides a conceptual basis and a whole new paradigm for understanding how muscles communicate with other organs, such as adipose tissue, liver, pancreas, bones and brain. However, some myokines exert their effects within the muscle itself. Thus, myostatin, LIF, IL-6 and IL-7 are involved in muscle hypertrophy and myogenesis, whereas BDNF and IL-6 are involved in AMPK-mediated fat oxidation. IL-6 also appears to have systemic effects on the liver, adipose tissue and the immune system, and mediates crosstalk between intestinal L cells and pancreatic islets. Other myokines include the osteogenic factors IGF-1 and FGF-2; FSTL-1, which improves the endothelial function of the vascular system; and the PGC-1α-dependent myokine irisin, which drives brown-fat-like development. Studies in the past few years suggest the existence of yet unidentified factors, secreted from muscle cells, which may influence cancer cell growth and pancreas function. Many proteins produced by skeletal muscle are dependent upon contraction; therefore, physical inactivity probably leads to an altered myokine response, which could provide a potential mechanism for the association between sedentary behaviour and many chronic diseases.

High bone density and bone health

The aim of this paper is to review the main aspects related to high bone density (HBD) as well as to discuss the physiologic mechanisms involved in bone health. There are still no well-defined criteria for identification of individuals with HBD and there are few studies on the topic. Most studies demonstrate that overweight, male gender, black ethnic background, physical activity, calcium and fluoride intake and use of medications such as statins and thiazide diuretics play a relevant and positive role on bone mineral density. Moreover, it is known that individuals with certain diseases such as obesity, diabetes, estrogen receptor-positive breast or endometrial cancer have greater bone density than healthy individuals, as well as athletes having higher bone density than non-athletes does not necessarily mean that they have healthy bones. A better understanding of risk and protective factors may help in the management of patients with bone frailty and have applicability in the treatment and in the prevention of osteoporosis, especially intervening on non-modifiable risk factors.

Evaluation of the bone status in high-level cyclists

The purpose of this study was to evaluate the bone status in highly trained professional cyclists subjected to regular training and tough competitions. Bone mineral density (BMD) was measured at different regions of interest by dual-energy X-ray absorptiometry, and main biological parameters related to bone metabolism were obtained in 29 cyclists. Lumbar BMD was 0.94 ± 0.01g/cm(2) (Z-score=-1.28 ± 0.07), and 1 cyclist out of 4 had an abnormally low value (Z-score <-2). The mean Z-score at the total femoral site was -1.22 ± 0.21, and 45% of athletes had an Z-score of <-2. All femoral neck BMD values were within normal boundaries. The lowest BMD Z-score was measured at the midradius or 1/3 proximal site with a mean Z-score of -1.77 ± 0.78, but only 3 cyclists (15%) had Z-scores <-2. Biochemical parameters of bone formation (serum osteocalcin and alkaline phosphatase) were normal. Three cyclists had low 25-hydroxyvitamin D levels. Blood testosterone and thyroid stimulating hormone were in the normal range. Insulin-like growth factor 1 levels were in the normal range; however, a significant inverse correlation was found with lumbar BMD (r=0.495; p=0.003). We confirm that cycling has no positive effect on BMD, BMD being often lower than in normal controls at the lumbar site; femoral BMD is less concerned. The absence of beneficial changes at the spine can be explained by biomechanical conditions related to the cyclists' position, reducing loading strains. It is necessary to pay greater attention to the bone status of high-level athletes to prevent an increased risk of fractures.

Physical activity: the forgotten tool for type 2 diabetes management

Individuals who are currently sedentary, unfit, or overweight can benefit metabolically from simply taking breaks from sitting. Since avoidance of sedentary behavior appears to have a large impact on glycemic management, all individuals with type 2 diabetes should be encouraged to minimally engage in greater daily movement to better manage their diabetes and body weight. In addition, engaging in physical activity of any intensity (including low-intensity ones) likely positively impacts insulin action and blood glucose control acutely. Moreover, as long as total caloric expenditure during exercise is matched (i.e., total exercise dose), daily exercise may be done every other day instead with the same glycemic results, although at least 150 min of weekly physical activity is recommended. Both aerobic and resistance training are important for individuals with diabetes, and ideally a program that combines the two types of training should be undertaken to achieve maximal glycemic and other benefits. Once individuals have successfully implemented more daily movement into their lifestyle, they will be more likely to participate in structured forms of physical activity to gain additional benefits. All clinicians working with individuals with either type 2 diabetes or prediabetes should consider incorporating these suggestions into care plans to improve their patients' glycemic management.