Association between bone, body composition and strength in premenarcheal girls and postmenopausal women

Changes in physical activity and risk of fracture: a Korean nationwide population-based cohort study

Physical activity (PA) is one of the most important modifiable factors associated with fracture risk. However, the association between interval changes in PA and the risk of fracture remains unknown. We investigated the risk of fracture development according to interval changes in PA in middle aged and older individuals. In this nationwide cohort study of adults aged ≥ 40 years, more than 4.9 million individuals without fractures within the last year who underwent two consecutive national health screenings in Korea from 2009 to 2012 were identified. The risk of fracture between 2013 and 2016 according to interval changes in regular PA was prospectively analyzed. Compared to individuals with a continuous lack of PA, those with a decrease in PA (0.41/1000 person-years (PY) decrease in incidence rate (IR); adjusted hazard ratio (aHR) 0.975; 95% confidence interval (CI) 0.964–0.987), increase in PA (1.8/1000 PY decrease in IR; aHR 0.948; 95% CI 0.937–0.959), and continuous PA (3.58/1000 PY decrease in IR; aHR 0.888; 95% CI 0.875–0.901) had a significantly reduced risk of fracture. Interval changes in regular PA were associated with risk of fracture. Individuals who engaged in continuous regular PA exhibited the maximum protective benefit against fracture.

Physical function assessment of older adults with lower body fractures at 3 months post-discharge from hospital

Background and purpose

Physical function assessment can be performed to assess functional mobility among older adults, especially after a traumatic incident such as lower body fracture (LBF). The objective of this study was to evaluate physical function of older patients with LBF after 3 months of discharge from the hospital.

Patients and methods

A total of 89 patients were followed up at the discharge phase. Four independent variables were tested: age, sex, type of fracture, and use of a walking aid before fracture. Mobility and strength were assessed with the Timed Up and Go (TUG) test and hand-grip strength (HGS) test, respectively.

Results

The majority of the patients were ≥65 years old (64%), female (61.8%), of Chinese ethnicity (50.6%), and had a hip fracture (51.7%). The mean time for TUG test was 26.11 seconds, while mean HGS was 19.02 kg. We found significant differences in TUG test scores with respect to all independent variables tested: age (P=0.026), sex (P=0.011), fracture type (P<0.001), and use of a walking aid before fracture (P=0.004). Significant differences were also detected in HGS test scores with respect to all independent variables tested: age (P<0.001), sex (P<0.001), fracture type (P<0.001), and use of a walking aid before fracture (P=0.035).

Conclusion

Increasing age, female sex, having a hip fracture, and use of a walking aid before fracture predicted reduction in the physical function and strength among older adults with LBF.

The health benefits of muscular fitness for children and adolescents: a systematic review and meta-analysis

BACKGROUND

Physical fitness during childhood and adolescence has been identified as an important determinant of current and future health status. While research has traditionally focused on the association between cardio-respiratory fitness and health outcomes, the association between muscular fitness (MF) and health status has recently received increased attention.

OBJECTIVE

The aim of this systematic review and meta-analysis was to evaluate the potential physiological and psychological benefits associated with MF among children and adolescents.

METHODS

A systematic search of six electronic databases (PubMed, SPORTDiscus, Scopus, EMBASE, PsycINFO and OVID MEDLINE) was performed on the 20th May, 2013. Cross-sectional, longitudinal and experimental studies that quantitatively examined the association between MF and potential health benefits among children and adolescents were included. The search yielded 110 eligible studies, encompassing six health outcomes (i.e., adiposity, bone health, cardiovascular disease [CVD] and metabolic risk factors, musculoskeletal pain, psychological health and cognitive ability). The percentage of studies reporting statistically significant associations between MF and the outcome of interest was used to determine the strength of the evidence for an association and additional coding was conducted to account for risk of bias. Meta-analyses were also performed to determine the pooled effect size if there were at least three studies providing standardised coefficients.

RESULTS

Strong evidence was found for an inverse association between MF and total and central adiposity, and CVD and metabolic risk factors. The pooled effect size for the relationship between MF and adiposity was r = -0.25 (95% CI -0.41 to -0.08). Strong evidence was also found for a positive association between MF and bone health and self-esteem. The pooled effect size for the relationship between MF and perceived sports competence was r = 0.39 (95% CI 0.34-0.45). The evidence for an association between MF and musculoskeletal pain and cognitive ability was inconsistent/uncertain. Where evidence of an association was found, the associations were generally low to moderate.

CONCLUSION

The findings of this review highlight the importance of developing MF in youth for a number of health-related benefits.

Association between bone mineralization, body composition, and cardiorespiratory fitness level in young Australian men

The critical age for attainment of peak bone mineralization is however 20-30 yr, but few studies have investigated bone mineralization and its association with body composition and cardiorespiratory fitness level in young men. This study aimed to investigate relationships between age, bone mineral measurements, body composition measurements, and cardiorespiratory fitness level in a group of young healthy Australian men. Thirty-five healthy men aged 18-25 yr had anthropometric measures, body composition, and cardiorespiratory fitness level assessed. Bone mineral content was significantly associated with height, body mass and lean mass, and bone mineral density positively correlated with lean mass and body mass. Bone mineral measurements did not correlate with fat mass, percentage of fat mass, or cardiorespiratory fitness level. Age was directly correlated with total body mass, body fat, and percentage of fat mass. Body mineral measurements correlated with lean mass but not with fat mass or with cardiorespiratory fitness in this group of young healthy men. Positive association between body fat and age in such young group suggests that more studies with young men are warranted and may help inform strategies to optimize increase in bone mineral measurements.

The role of physical activity and diet on bone mineral indices in young men: a cross-sectional study

Background

Osteoporotic fractures are a significant cause of morbidity and mortality, particularly in developed countries. Increasing peak bone mass in young people may be the most important primary prevention strategy to reduce the risk of osteoporosis. This study aimed to examine the relationship between dietary factors and physical activity on bone mineralization in young men.

Methods

Thirty-five healthy men aged 18–25 y had anthropometric measures, body composition, resting metabolic rate, blood pressure, blood lipids, food intake, physical activity and cardiorespiratory fitness assessed.

Results

Participants who consumed more than 1000 mg/d of calcium were taller and had higher levels of whole body mineral content than participants who consumed less than 1000 mg/d of calcium. Similarly, participants who expended more than 20% of total daily energy engaged in moderate- to vigorous-intensity physical activity had higher cardiorespiratory fitness and higher levels of body mass adjusted bone mineral content than participants who did not meet this level of energy expenditure. There were no differences in blood pressure or blood lipids between participants in calcium or in physical activity energy expenditure categories.

Conclusions

A high intake of dietary calcium and high daily energy expenditure engaged in moderate- to vigorous-intensity physical activity were positively associated with bone mineralization in young men, particularly in the lumbar region.

Age determines longitudinal changes in body composition better than menopausal and bone status: the OFELY study

Long-term body composition (BC) changes and their determinants have been rarely explored. We aimed to evaluate BC changes in French women from the Os des Femmes de Lyon (OFELY) cohort and to explore several determinants of those changes. At baseline, premenopausal (PreM) women (n = 145) had lower fat body mass (FM) and greater lean body mass (LM), relative skeletal muscle mass index (RASM), and total body bone mineral content (TBBMC) compared with untreated postmenopausal (PostM) women (n = 412). During a 6-year follow-up, LM and RASM did not change, whereas a significant increase of FM and a decrease of TBBMC were observed in PreM (n = 88) and PeriM women (n = 44; women who became PostM during the follow-up). In untreated PostM women, FM increased, whereas LM, RASM, and TBBMC decreased (p < 0.0001). Age was a significant determinant of the changes in BC. After controlling for age, menopausal status was still a significant determinant only for changes in TBBMC. FM, LM, RASM, and TBBMC were higher in women with normal bone mineral density (BMD) compared with women with osteopenia or osteoporosis (p < 0.0001), but after adjusting for age, changes of BC were not significantly different according to the bone status. After controlling for age and menopausal status, levels of P1NP in the highest quartile were associated with a greater decrease of LM and RASM compared with lower levels. In conclusion, BC changes in French women over a 6-year follow-up showed a high interindividual variability. Aging may be the most important determinant of changes in body composition, rather than menopausal and bone status.

Greater lean tissue and skeletal muscle mass are associated with higher bone mineral content in children

BACKGROUND

To compare the relationship of skeletal muscle mass with bone mineral content in an ethnically diverse group of 6 to 18 year old boys and girls.

METHODS

175 healthy children (103 boys; 72 girls) had assessments of body mass, height, and Tanner stage. Whole body bone mineral content, non-bone lean body mass (nbLBM), skeletal muscle mass, and fat mass were assessed using dual-energy X-ray absorptiometry (DXA). Muscle mass was estimated from an equation using appendicular lean soft tissue measured by DXA, weight and height. Estimates of skeletal muscle mass and adipose tissue were also assessed by whole body multi-slice magnetic resonance imaging (MRI). Linear regression was used to determine whether skeletal muscle mass assessed by DXA or by MRI were better predictors of bone mineral content compared with nbLBM after adjusting for sex, age, race or ethnicity, and Tanner stage.

RESULTS

Greater skeletal muscle mass was associated with greater bone mineral content (p < 0.001). The skeletal muscle mass assessed by MRI provided a better fitting regression model (determined by R2 statistic) compared with assessment by DXA for predicting bone mineral content. The proportion of skeletal muscle mass in nbLBM was significantly associated with greater bone mineral content adjusted for total nbLBM.

CONCLUSIONS

This study is among the first to describe and compare the relationship of skeletal muscle to bone using both MRI and DXA estimates. The results demonstrate that the use of MRI provides a modestly better fitting model for the relationship of skeletal muscle to bone compared with DXA. Skeletal muscle had an impact on bone mineral content independent of total non-bone lean body mass. In addition, Hispanics had greater bone mineral content compared to other race and ethnic groups after adjusting for sex, age, adipose tissue, skeletal muscle mass, and height.

Changes in soft tissue composition are the primary predictors of 4-year bone mineral density changes in postmenopausal women

Changes in body weight influence bone mineral density, but the role of body composition is not clear in postmenopausal women. Body weight and soft tissue composition predicted bone changes independent of calcium supplementation and exercise frequency, indicating that soft tissue composition should be measured in clinical trials.

INTRODUCTION

The purpose of this study was to examine the relationship between changes in body weight and composition and changes in 4-year bone mineral density (BMD) after accounting for age, 4-year exercise frequency (EX), and 4-year calcium supplement intake (CA) in postmenopausal women with and without hormone therapy (HT).

METHODS

Postmenopausal women (aged 40-65 years) either using HT (for 1-3.9 years) or not using HT (for > or =1 year) were recruited to the study. EX and CA was monitored throughout the study and 167 women completed 4 years. BMD and soft tissue composition measurements were made using dual-energy X-ray absorptiometry. Regression was used to predict 4-year BMD changes from EX, CA, age, baseline and 4-year changes in body weight and composition. HT users (n = 115, 55.3 +/- 4.3 years) and non-users (n = 52, 57.5 +/- 4.7 years) were analyzed separately.

RESULTS

The models predicting regional BMD changes that included soft tissue composition changes explained the most variation compared with those with body weight or EX and CA alone. Larger amounts of variation in BMD changes were explained in the no HT group.

CONCLUSION

Body composition changes are important positive predictors of BMD changes independent of EX and CA supplementation, but their contribution varies according to bone site and with HT use.

The influence of lifestyle, menstrual function and oral contraceptive use on bone mass and size in female military cadets

Purpose

To determine the influence of menstrual irregularity, oral contraceptive use and other factors on bone mineral density (BMD) and bone size at different skeletal sites in 135 college-aged fit women.

Methods

Menstrual history, oral contraceptive use, exercise history, and nutritional factors including calcium, caffeine, and alcohol intake as well as tobacco use were determined by written survey. Height, weight and fitness levels were measured. Spine and hip BMD were measured by dual x-ray absorptiometry (DXA), calcaneus BMD by peripheral DXA, and tibial bone mineral content (BMC) and size by peripheral Quantitative Computed Tomography (pQCT).

Results

The mean age was 18.4 ± 0.8 years. Weight and prior exercise were positively related to BMD at most skeletal sites and to tibial bone size. Milk intake was positively related to calcaneal BMD, tibial BMC and cortical thickness. Fracture history was an important predictor of spine, hip and heel BMD. Women who had ≥ 10 menstrual cycles in the year prior to BMD measurement had higher BMD at all sites as well as a greater tibial mineral content and cortical thickness than women who had oligomenorrhea/amenorrhea (≤ 9 cycles in the prior year; all p < 0.05). Oral Contraceptive (OC) users had significantly lower BMD in the spine (p < 0.02) and calcaneus (p = 0.04), smaller tibial periosteal circumference and lower tibial mineral content (p < 0.02) than non-OC users.

Conclusion

In a population of fit, college-aged women, OC use and oligomenorrhea were associated with reduced BMD and bone size. Weight, as well as prior exercise and milk intake was positively related to bone density and size at some skeletal sites. Understanding these relationships would help improve skeletal health in young women.

Bone mineral density and leg muscle strength in young Caucasian, Hispanic, and Asian women

Differences in bone mineral density (BMD) of ethnically diverse populations are usually attributed to anthropometric characteristics, but may also be due to life style or diet. We studied healthy young sedentary women with Asian (ASN, n=40), Hispanic (HIS, n=39), or Caucasian (CAU, n=36) backgrounds. Body composition and regional BMD were measured by dual-energy X-ray absorptiometry (Hologic) or PIXI (Lunar GE) for the heel and wrist). Leg strength was quantified with a leg press and dietary calcium was estimated with 3-d diet records. CAU were taller than HIS and ASN (p<0.01). ASN had lower body weights, fat mass, lean body mass, and leg strength than HIS or CAU (p<0.01). Differences in BMD among groups were not eliminated by adjusting for body weight and height at the arm, trochanter, femoral neck, and total hip where BMD values remained lower in the ASN than in HIS or CAU (p<0.01). Conversely, adjusted BMD at the wrist was 7.3% higher in ASN and 8.3% higher in HIS and at the heel, 7.3% higher in ASN and 7.0% higher in HIS than in CAU (p<0.05). Leg strength was a significant predictor of BMD in the hip in CAU (R=0.53, p=0.004), in the hip with dietary calcium in ASN (R=0.65, p=0.02), and in the heel with height in HIS (R=0.57, p=0.03). We conclude that significant factors underlying BMD in ethnically diverse young women vary as a function of ethnicity and include leg strength and dietary calcium as well as anthropometric characteristics.

Determinants of peak bone mineral density and bone area in young women

Osteoporosis is a disease caused by compromised bone strength, and individuals with a high peak bone mass at a young age are likely to have a high bone mass in old age. To identify the clinical determinants of peak bone mass in young adult women, 418 southern Chinese women, aged 20-39 years, were studied. Low bone mass was defined as areal bone mineral density (aBMD) Z-score < -1 at either the spine or total hip. Within the cohort, 62 (19.0%) and 86 (26.4%) women had low aBMD at the spine and hip, respectively. Regression model analysis revealed that low body weight (<44 kg) was associated with an 8.3-fold (95% CI, 3.7-18.9) and a 6.8-fold (95% CI, 3.0-15.6) risk of having low aBMD at the spine and hip, respectively. Low body weight was also predictive of low volumetric BMD (vBMD) at the spine (odds ratio (OR) 7.8, 95% CI, 3.1-20.1) and femoral neck (OR 3.0, 95% CI, 1.3-7.1). A body height below 153 cm was associated with a 4.8-fold risk in the small L2-4 bone area (95% CI, 2.3-9.8) and a 3.9-fold risk in the small femoral neck area (95% CI, 1.9-8.1). Delayed puberty (onset of menstruation beyond 14 years) was associated with a 2.2-fold (95% CI, 1.0-4.9) increased risk of having low aBMD at the hip. Physical inactivity was associated with a 2.8-fold risk of low spine vBMD (OR 2.8, 95% CI, 1.1-6.7) and a 3.3-fold risk of low hip aBMD (95% CI, 1.0-10.0). Pregnancy protected against low spine aBMD (OR 0.4, 95% CI, 0.1-1.2) and spine vBMD (OR 0.1, 95% CI, 0.0-1.0), low femoral neck vBMD (OR 0.3, 95% CI, 0.1-1.1) and small L2-4 bone area vBMD (OR 0.3, 95% CI, 0.1-1.1). In conclusion, this study identified a number of modifiable determinants of low peak bone mass in young adult women. Maintaining an ideal body weight, engaging in an active lifestyle, and diagnosing late menarche may enable young women to maximize their peak bone mass and so reduce their risk of osteoporosis in later life.