Previous sport activity during childhood and adolescence is associated with increased cortical bone size in young adult men

Does higher serum 25-hydroxyvitamin D levels will harm bone mineral density?: a cross-sectional study

OBJECTIVE

Vitamin D plays a critical role in the prevention and management of osteoporosis. However, there is an ongoing debate regarding the most effective vitamin D supplementation strategies for maintaining optimal bone mineral density (BMD) levels in adults. This study sought to establish the correlation between serum 25-hydroxyvitamin D [25(OH)D] levels and total BMD in a substantial population sample.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) for the 2011-2018 cycles, encompassing 11,375 adult participants, were analyzed. The primary variables of interest were serum 25(OH)D levels and BMD. A multivariable logistic regression model was utilized to account for relevant variables associated with these correlations.

RESULTS

A U-shaped relationship between serum 25(OH)D levels and BMD was observed. In males, a significant positive association was identified for 25(OH)D levels below 84.8 nmol/L (p < 0.0001), while levels above this threshold showed no significant correlation (p = 0.3377). In females, those with 25(OH)D levels below 31.4 nmol/L exhibited a significant positive association with BMD (p = 0.0010), but this association weakened and became marginally significant above this threshold (p = 0.0650).

CONCLUSIONS

For adult males, the optimal serum 25(OH)D level is 84.8 nmol/L, beyond which higher levels do not lead to increased BMD. A deficiency threshold for adult females should be above 31.4 nmol/L, as lower 25(OH)D levels are not conducive to BMD. These findings underscore the importance of maintaining appropriate vitamin D levels for bone health in both genders.

An Opinion on the Interpretation of Bone Turnover Markers Following Acute Exercise or Nutrition Intervention and Considerations for Applied Research

It is important for athlete and public health that we continue to develop our understanding of the effects of exercise and nutrition on bone health. Bone turnover markers (BTMs) offer an opportunity to accelerate the progression of bone research by revealing a bone response to exercise and nutrition stimuli far more rapidly than current bone imaging techniques. However, the association between short-term change in the concentration of BTMs and long-term bone health remains ambiguous. Several other limitations also complicate the translation of acute BTM data to applied practice. Importantly, several incongruencies exist between the effects of exercise and nutrition stimuli on short-term change in BTM concentration compared with long-term bone structural outcomes to similar stimuli. There are many potential explanations for these inconsistencies, including that short-term study designs fail to encompass a full remodeling cycle. The current article presents the opinion that data from relatively acute studies measuring BTMs may not be able to reliably inform applied practice aiming to optimize bone health. There are important factors to consider when interpreting or translating BTM data and these are discussed.

Relationship between Femur Mineral Content and Local Muscle Strength and Mass

Among the stimuli able to prevent early decreases in bone mineralization, exercise has a noticeable role per se as the source of mechanical stimulus or through lean tissue enlargement by its increasing of tensional stimulus. However, prevention strategies, including exercise, generally do not establish the moment in life when attention should begin to be paid to bone integrity, according to age group- and sex-related differences. Thus, this study analyzed the relationship between variables from the diagnosis of total and regional body composition, muscle strength, and bone mineral content (BMC) of femurs in young adult males. Thirty-four young Caucasian men (24.9 ± 8.6 years) had their body composition and bone density assessed by dual X-ray absorptiometry. The subjects performed a one-repetition maximum test (1-RM) in a bench press, front pulley, seated-row, push press, arm curl, triceps pulley, leg flexion, leg extension, and 45° leg press for the assessment of muscle strength in upper and lower limbs in single- and multi-joint exercises. Lean tissue mass in the trunk and upper and lower limbs were related to femoral BMC (Pearson coefficient ranging from 0.55 to 0.72, p < 0.01), and 1-RM values for different exercises involving both upper and lower limbs also correlated with femoral BMC (Pearson coefficients ranging from 0.34 to 0.46, p < 0.05). Taken together, these correlations suggest that muscle mass and strength are positively linked with the magnitude of femoral mass in men, even in early adulthood. Hence, the importance of an enhanced muscle mass and strength to the health of femoral bones in young adults was highlighted.

Determinants of Z-Score of Bone Mineral Density among Premenopausal Saudi Females in Different Age Groups: A Cross Sectional Study

This is a comparative multicenter cross-sectional study that evaluated the potential determinants of Z-scores among premenopausal Saudi women before and after the age of peak bone density. The Study concluded that for better BMD among premenopausal women, attention should be paid to early physical activity and healthy nutrition, especially vitamin D, during the childbearing period.

OBJECTIVE

To explore the potential determinants of Z-scores among premenopausal Saudi females in different age groups before and after the expected age of peak bone density (PBD).

METHODS

This multicenter comparative cross-sectional study was conducted in Madinah and Jeddah, Saudi Arabia, between August 2021 and March 2022. We recruited 886 premenopausal females (605 (68.3%) below and 281 (31.7%) at or above the age of 30). The structured pre-coded Arabic questionnaire included sociodemographic data, a BMD questionnaire, menstrual history, an Arab Teen Lifestyle Study questionnaire, and food frequency data. Metabolic Equivalents (METs) were calculated from physical activity. Analysis of serum PTH, 25(OH) vitamin D (VD) was performed with chemiluminescent immunoassay. BMD was measured with a calcaneal qualitative ultrasound.

RESULTS

Most women had age-matched Z-scores, with very few (24 (2.7%)) being non-age-matched with no identified secondary causes. Significant Z-score determinants before PBD were BMI (OR: 0.167, p = 0.003) and total METs (OR: 0.160, p < 0.005). After the age of PBD, significant predictors were parity (OR: 0.340, p = 0.042), history of vitamin D deficiency (OR: 0.352, p = 0.048), and BMI (OR: 0.497, p = 0.019).

CONCLUSIONS

Early determinants of Z-scores among premenopausal women were the nutritional status and physical activity. After the age of PBD, parity and vitamin D status offer additional determinants. For better BMD, attention should be paid to early physical activity and healthy nutrition, especially for vitamin D, with intensification of efforts during the childbearing period.

Association Between Persistent Treatment of Alzheimer's Dementia and Osteoporosis Using a Common Data Model

Background and Purpose

As it becomes an aging society, interest in senile diseases is increasing. Alzheimer's dementia (AD) and osteoporosis are representative senile diseases. Various studies have reported that AD and osteoporosis share many risk factors that affect each other's incidence. This aimed to determine if active medication treatment of AD could affect the development of osteoporosis.

Methods

The Health Insurance Review and Assessment Service provided data consisting of diagnosis, demographics, prescription drug, procedures, medical materials, and healthcare resources. In this study, data of all AD patients in South Korea who were registered under the national health insurance system were obtained. The cohort underwent conversion to an Observational Medical Outcomes Partnership-Common Data Model version 5 format.

Results

This study included 11,355 individuals in the good persistent group and an equal number of 11,355 individuals in the poor persistent group from the National Health Claims database for AD drug treatment. In primary analysis, the risk of osteoporosis was significantly higher in the poor persistence group than in the good persistence group (hazard ratio, 1.20 [95% confidence interval, 1.09-1.32]; p<0.001).

Conclusions

We found that the good persistence group treated with anti-dementia drugs for AD was associated with a significant lower risk of osteoporosis in this nationwide study. Further studies are needed to clarify the pathophysiological link in patients with two chronic diseases.

Relationship between Football-Specific Training Characteristics and Tibial Bone Adaptation in Male Academy Football Players

We examined the relationship between football-specific training and changes in bone structural properties across a 12-week period in 15 male football players aged 16 years (Mean ± 1 SD = 16.6 ± 0.3 years) that belonged to a professional football academy. Tibial scans were performed at 4%, 14% and 38% sites using peripheral quantitative computed tomography immediately before and 12 weeks after increased football-specific training. Training was analysed using GPS to quantify peak speed, average speed, total distance and high-speed distance. Analyses were conducted with bias-corrected and accelerated bootstrapped 95% confidence intervals (BCa 95% CI). There were increases in bone mass at the 4% (mean ∆ = 0.15 g, BCa 95% CI = 0.07, 0.26 g, g = 0.72), 14% (mean ∆ = 0.04 g, BCa 95% CI = 0.02, 0.06 g, g = 1.20), and 38% sites (mean ∆ = 0.03 g, BCa 95% CI = 0.01, 0.05 g, g = 0.61). There were increases in trabecular density (4%), (mean ∆ = 3.57 mg·cm^-3, BCa 95% CI = 0.38, 7.05 mg·cm^-3, g = 0.53), cortical dentsity (14%) (mean ∆ = 5.08 mg·cm^-3, BCa 95% CI = 0.19, 9.92 mg·cm^-3, g = 0.49), and cortical density (38%) (mean ∆ = 6.32 mg·cm^-3, BCa 95% CI = 4.31, 8.90 mg·cm^-3, g = 1.22). Polar stress strain index (mean ∆ = 50.56 mm³, BCa 95% CI = 10.52, 109.95 mm³, g = 0.41), cortical area (mean ∆ = 2.12 mm², BCa 95% CI = 0.09, 4.37 mm², g = 0.48) and thickness (mean ∆ = 0.06 mm, BCa 95% CI = 0.01, 0.13 mm, g = 0.45) increased at the 38% site. Correlations revealed positive relationships between total distance and increased cortical density (38%) (r = 0.39, BCa 95% CI = 0.02, 0.66), and between peak speed and increased trabecular density (4%) (r = 0.43, BCa 95% CI = 0.03, 0.73). There were negative correlations between total (r = -0.21, BCa 95% CI = -0.65, -0.12) and high-speed distance (r = -0.29, BCa 95% CI = -0.57, -0.24) with increased polar stress strain index (38%). Results suggest that despite football training relating to increases in bone characteristics in male academy footballers, the specific training variables promoting adaptation over a 12-week period may vary. Further studies conducted over a longer period are required to fully elucidate the time-course of how certain football-specific training characteristics influence bone structural properties.

The effect of the exercise environment and the level of involvement on bone mineral health

INTRODUCTION

This study aimed to compare athletes practicing exercise in different environments with non-active young and elderly men and women regarding bone mineral density (BMD), hypothesizing that BMD values differ between athletes according to the environment of exercise practice, but those training in a low-gravitational environment have no different stimuli to BMD increasing if compared with healthy peers experiencing reduced exercise involvement, whatever the age group and sex.

MATERIALS AND METHODS

104 participants of both sexes were selected according to the environment of exercise practice [swimmers (N = 26) and judo fighters (N = 26)], and exercise level of involvement [non-active young (N = 26) and older adults (N = 26)]. Dual-energy X-ray absorptiometry provided BMD, lean mass, and fat mass (FM) for the whole body (WB), upper (UL), and lower limbs (LL).

RESULTS

For the BMD in WB, UL and LL no effects of group and sex were observed (p > 0.05). Post-hoc analyses detected higher values of BMD in UL for female swimmers compared to non-active older adults (p < 0.05), while judo fighters showed higher BMD in WB, UL, and LL than other participants whatever the sex (p < 0.01). Lower FM was observed for WB, UL, and LL when swimmers and judo fighters were compared to non-active young and older female peers (p < 0.01).

CONCLUSION

The findings emphasized that BMD stimuli with swimming are reduced when compared to judo, and despite the stimuli in swimming is not distinguishable from that affecting BMD in WB, UL and LL of non-active young, it is effective in differing BMD in UL among non-active older for women.

Bone Tissue Responsiveness To Mechanical Loading-Possible Long-Term Implications of Swimming on Bone Health and Bone Development

PURPOSE OF REVIEW

To revisit the bone tissue mechanotransduction mechanisms behind the bone tissue response to mechanical loading and, within this context, explore the possible negative influence of regular swimming practice on bone health, particularly during the growth and development period.

RECENT FINDINGS

Bone is a dynamic tissue, responsive to mechanical loading and unloading, being these adaptative responses more intense during the growth and development period. Cross-sectional studies usually report a lower bone mass in swimmers compared to athletes engaged in weigh-bearing sports. However, studies with animal models show contradictory findings about the effect of swimming on bone health, highlighting the need for longitudinal studies. Due to its microgravity characteristics, swimming seems to impair bone mass, but mostly at the lower limbs. It is unkown if there is a causal relationship between swimming and low BMD or if other confounding factors, such as a natural selection whithin the sport, are the cause.

Genetic Risk for Osteoporosis and the Benefit of Adherence to Healthy Lifestyles

Objectives: We aimed to explore how healthy lifestyles and genetic factors influence the risk of Osteoporosis (OP). Methods: In this prospective cohort study, we first performed a genome-wide association study (GWAS) of estimated bone mineral density (eBMD) and constructed the genetic risk score (GRS) based on the effect of single nucleotide polymorphism (SNP) on eBMD. We then assessed the effect of three-level GRS and adherence to healthy lifestyles on the risk of OP and fracture, respectively. Finally, we assessed the joint effects of GRS and lifestyle on the OP and fracture risk. Results: People with higher GRS have a lower risk of OP and fracture. Negative associations were detected between healthy lifestyle factors and the risk of OP and fracture. Compare with the group with high GRS and favorable lifestyles, the group with low GRS and unfavorable lifestyles had a high Hazard Ratio (HR). Conclusion: The findings suggest that adherence to healthy lifestyles can reduce the risk of OP and fracture in people with different genetic risks.

Nutrition, Physical Activity, and Dietary Supplementation to Prevent Bone Mineral Density Loss: A Food Pyramid

Bone is a nutritionally modulated tissue. Given this background, aim of this review is to evaluate the latest data regarding ideal dietary approach in order to reduce bone mineral density loss and to construct a food pyramid that allows osteopenia/osteoporosis patients to easily figure out what to eat. The pyramid shows that carbohydrates should be consumed every day (3 portions of whole grains), together with fruits and vegetables (5 portions; orange-colored fruits and vegetables and green leafy vegetables are to be preferred), light yogurt (125 mL), skim milk (200 mL,) extra virgin olive oil (almost 20 mg/day), and calcium water (almost 1 l/day); weekly portions should include fish (4 portions), white meat (3 portions), legumes (2 portions), eggs (2 portions), cheeses (2 portions), and red or processed meats (once/week). At the top of the pyramid, there are two pennants: one green means that osteopenia/osteoporosis subjects need some personalized supplementation (if daily requirements cannot be satisfied through diet, calcium, vitamin D, boron, omega 3, and isoflavones supplementation could be an effective strategy with a great benefit/cost ratio), and one red means that there are some foods that are banned (salt, sugar, inorganic phosphate additives). Finally, three to four times per week of 30-40 min of aerobic and resistance exercises must be performed.

Short-Term Increased Physical Activity During Early Life Affects High-Fat Diet-Induced Bone Loss in Young Adult Mice

Mechanical stresses associated with physical activity (PA) have beneficial effects on increasing BMD and improving bone quality. However, a high-fat diet (HFD) and obesity tend to have negative effects on bone, by increasing bone marrow adiposity leading to increased excretion of proinflammatory cytokines, which activate RANKL-induced bone resorption. In the current study, whether short-term increased PA via access to voluntary wheel running during early life has persistent and protective effects on HFD-induced bone resorption was investigated. Sixty 4-week-old male C57BL6/J mice were divided into two groups postweaning: without or with PA (access to voluntary running wheel 7-8 km/day) for 4 weeks. After 4 weeks with or without PA, mice were further subdivided into control diet or HFD groups for 8 weeks, and then all animals were switched back to control diet for an additional 4 weeks. Mice from the HFD groups were significantly heavier and obese; however, after 4 weeks of additional control diet their body weights returned to levels of mice on continuous control diet. Using μ-CT and confirmed by pQCT of tibias and spines ex vivo, it was determined that bone volume and trabecular BMD were significantly increased with PA in control diet animals compared with sedentary animals without access to wheels, and such anabolic effects of PA on bone were sustained after ceasing PA in adult mice. Eight weeks of a HFD deteriorated bone development in mice. Unexpectedly, early-life PA did not prevent persistent effects of HFD on deteriorating bone quality; in fact, it exacerbated a HFD-induced inflammation, osteoclastogenesis, and trabecular bone loss in adult mice. In accordance with these data, signal transduction studies revealed that a HFD-induced Ezh2, DNA methyltransferase 3a, and nuclear factor of activated T-cells 1 expression were amplified in nonadherent hematopoietic cells. In conclusion, short-term increased PA in early life is capable of increasing bone mass; however, it alters the HFD-induced bone marrow hematopoietic cell-differentiation program to exacerbate increased bone resorption if PA is halted. © 2021 Arkansas Children's Nutrition Center. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Factors influencing peak bone mass gain

Bone mass is a key determinant of osteoporosis and fragility fractures. Epidemiologic studies have shown that a 10% increase in peak bone mass (PBM) at the population level reduces the risk of fracture later in life by 50%. Low PBM is possibly due to the bone loss caused by various conditions or processes that occur during adolescence and young adulthood. Race, gender, and family history (genetics) are responsible for the majority of PBM, but other factors, such as physical activity, calcium and vitamin D intake, weight, smoking and alcohol consumption, socioeconomic status, age at menarche, and other secondary causes (diseases and medications), play important roles in PBM gain during childhood and adolescence. Hence, the optimization of lifestyle factors that affect PBM and bone strength is an important strategy to maximize PBM among adolescents and young people, and thus to reduce the low bone mass or osteoporosis risk in later life. This review aims to summarize the available evidence for the common but important factors that influence bone mass gain during growth and development and discuss the advances of developing high PBM.

Cardiorespiratory Fitness is Inversely Associated with Risk of Low Bone Mineral Density in Older Korean Men

Little is known regarding the association between physical fitness and bone health in older Korean men. This study investigated the relationship between estimated cardiorespiratory fitness (eCRF) and bone mineral density (BMD). This cross-sectional study included 2715 Korean men aged 50 years and older selected from those who participated in the 2008–2011 Korea National Health and Nutritional Examination and Survey. eCRF was obtained using a sex-specific algorithm developed on the basis of age, body mass index, resting heart rate, and physical activity and classified into low, middle, and high categories. Femoral neck BMD was assessed by dual X-ray absorptiometry. Odds ratios (OR) and 95% confidence intervals (CI) for osteopenia, osteoporosis, and low BMD were calculated for eCRF categories in models fully adjusted for age, waist circumference, education, income, smoking, heavy alcohol intake, serum vitamin D, serum parathyroid hormone, and dietary intake of energy, protein, calcium, and vitamins A and C. Overall, eCRF levels were positively associated with BMD and negatively with prevalence of osteopenia, osteoporosis, and low BMD. Logistic regression showed inverse trends in the risks of osteopenia (high vs. low: OR = 0.692; 95% CI, 0.328–0.517; p = 0.049) and low BMD (high vs. low: OR = 0.669; 95% CI, 0.497–0.966; p = 0.029) by eCRF category in models fully adjusted for all the measured covariates. The current findings suggest that maintaining high eCRF via regular physical activity may contribute to attenuation of age-related loss of BMD and decreased risk for low BMD in older Korean men.

Early and current physical activity: cross-sectional associations with overweight among adults

Introduction

The health benefits of physical activity in all ages are widely known, however the effects of early physical activity on future health are not yet fully understood. The aim of this study was to analyze the cross-sectional associations between previous and current physical activity with overweight among adults.

Methods

A probabilistic sample of 534 teachers was included in the study. Independent variables were physical activity in childhood, adolescence, and current, and clustering of the variables, all analyzed using a self-report questionnaire. The dependent variable was overweight, estimated by the body mass index, assessed using self-report measures of weight and height. Covariates were sex, age, skin color, income, sedentary behavior, medication use for weight control, and nutritionist counseling. Poisson regression was adopted to estimate Prevalence Ratios (PR) in the multivariate analysis.

Results

Physical activity at ages 6-10 (PR = 1.03 to 1.13), 12-14 (PR = 0.96 to 0.98), and 15-17 (PR = 0.76 to 0.90) years was not associated with overweight. Participants who do not meet the recommendation of current physical activity have a higher likelihood of being overweight (PR = 1.55 to 2.17) and the magnitude of the association increased when analyzing those who were not physically active through all periods analyzed (PR = 3.69 to 4.69).

Conclusion

Performing physical activity only in early life does not seem to promote health benefits in the sample analyzed. Although current physical activity is associated with the outcome, the promotion of both early and current physical activity seems to be a better strategy to prevent overweight among adults.

Body composition, strength static and isokinetic, and bone health: comparative study between active adults and amateur soccer players

Objective:

To compare tissue composition, total and regional bone mineral content and bone mineral density, static hand grip and knee joint isokinetic strength between amateur soccer players and Control Group.

Methods:

Cross-sectional study. Air displacement plethysmography was used to estimate body volume and, in turn, density. Body composition, bone mineral content and bone mineral density were assessed for the whole body and at standardized regions using dual energy X-ray absorptiometry. Static grip strength was assessed with an adjustable dynamometer, and peak torque derived from isokinetic strength dynamometer (concentric muscular knee actions at 60°/s). Magnitude of the differences between groups was examined using d-Cohen.

Results:

Compared to healthy active adults, soccer players showed larger values of whole body bone mineral content (+651g; d=1.60; p<0.01). In addition, differences between groups were large for whole body bone mineral density (d=1.20 to 1.90; p<0.01): lumbar spine, i.e. L1-L4 (+19.4%), upper limbs (+8.6%) and lower limbs (+16.8%). Soccer players attained larger mean values in strength test given by static hand grip protocol (+5.6kg, d=0.99; p<0.01).

Conclusion:

Soccer adequately regulates body composition and is associated better bone health parameters (bone mineral content and density at whole-body and at particular sites exposed to mechanical loadings).

Health Effects of Wrist-Loading Sports During Youth: A Systematic Literature Review

BACKGROUND

The benefits and risks of performing popular wrist-loading sports at a young age have not been investigated systematically. We aimed to evaluate positive and negative long-term wrist-related health effects of sports performance requiring repetitive wrist loading during youth.

METHODS

Six databases were searched for cohort and cross-sectional studies. Three investigators selected studies evaluating quantitatively measured health effects of upper extremities in athletes practicing wrist-loading sports (gymnastics, tennis, volleyball, field hockey, rowing, and judo) for minimally 4 months before the age of 18.

RESULTS

A total of 23 studies with 5 outcome measures, nearly all of moderate to good quality, were eligible for inclusion. Bone mineral density and bone mineral content were higher in athletes compared with controls and in tennis players' dominant arm. Mixed results were found for ulnar variance in gymnasts. Handgrip strength was greater in tennis players' dominant arm and in experienced gymnasts.

CONCLUSIONS

Wrist-loading sports performance during youth can promote bone strength in wrists and dominant handgrip strength, but evidence on the lasting of these effects and on prevalence of wrist joint degeneration in former young athletes is limited. For better counseling of young athletes and their parents, future studies with increased comparability are essential, for which recommendations are provided.

Japanese female Kendo practitioners are associated with high radial bone mineral density

Osteopenia is a condition in which bone mineral density (BMD) is lower than normal. Exercise increases BMD in both the young and adults. This study aimed to compare the radial apparent BMD (aBMD) in Japanese females who are Kendo practitioners (KPs) and those with no regular exercise habits (no-REH). The analysis participants consisted of 45 KPs (mean age: 49.4 years old) and 110 no-REH (mean age: 48.8 years old). Radial aBMD was measured using an ultrasonic bone densitometry system. Radial aBMD in KPs was 196.1 ± 33.9 mg/cm³, and was 182.9 ± 45.3 mg/cm³ in no-REH participants. KPs had significantly higher BMD than no-REH participants. In KPs, left radial aBMD was 196.1 ± 33.9 mg/cm³, and right radial aBMD was 184.5 ± 37.7 mg/cm³. The left radius was also significantly higher than the right radius with respect to aBMD in KPs. After adjusting for age, body mass index, menstrual status, parous women and frequency of milk and dairy intake, the odds ratio (OR) of osteopenia associated with no-REH was 6.58 (95% confidence interval (CI): 1.72-25.1) and the prevalence ratio (PR) of osteopenia associated with no-REH was 4.12 (95% CI: 1.23-13.7). Therefore, the Kendo practice may have a protective efficacy for osteopenia in women.

Current Physical Activity Is Independently Associated With Cortical Bone Size and Bone Strength in Elderly Swedish Women

Physical activity is believed to have the greatest effect on the skeleton if exerted early in life, but whether or not possible benefits of physical activity on bone microstructure or geometry remain at old age has not been investigated in women. The aim of this study was to investigate if physical activity during skeletal growth and young adulthood or at old age was associated with cortical geometry and trabecular microarchitecture in weight-bearing and non-weight-bearing bone, and areal bone mineral density (aBMD) in elderly women. In this population-based cross-sectional study 1013 women, 78.2 ± 1.6 (mean ± SD) years old, were included. Using high-resolution 3D pQCT (XtremeCT), cortical cross-sectional area (Ct.CSA), cortical thickness (Ct.Th), cortical periosteal perimeter (Ct.Pm), volumetric cortical bone density (D.Ct), trabecular bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp) were measured at the distal (14% level) and ultra-distal tibia and radius, respectively. aBMD was assessed using DXA (Hologic Discovery A) of the spine and hip. A standardized questionnaire was used to collect information about previous exercise and the Physical Activity Scale for the Elderly (PASE) was used for current physical activity. A linear regression model (including levels of exercise during skeletal growth and young adulthood [10 to 30 years of age], PASE score, and covariates) revealed that level of current physical activity was independently associated with Ct.CSA (β = 0.18, p < 0.001) and Ct.Th (β = 0.15, p < 0.001) at the distal tibia, Tb.Th (β = 0.11, p < 0.001) and BV/TV (β = 0.10, p = 0.001) at the ultra-distal tibia, and total hip aBMD (β = 0.10, p < 0.001). Current physical activity was independently associated with cortical bone size, in terms of thicker cortex but not larger periosteal circumference, and higher bone strength at the distal tibia on elderly women, indicating that physical activity at old age may decrease cortical bone loss in weight-bearing bone in elderly women. © 2016 American Society for Bone and Mineral Research.

Global participation in sport and leisure-time physical activities: A systematic review and meta-analysis

This review aimed to determine the most popular physical activities performed by children, adolescents, and adults globally. Statistic bureau websites and article databases Scopus, ProQuest, SPORTDiscus, and Science Direct were searched between November 17th, 2014 and April 31st, 2015. Eligible studies were published in the last 10years with participation rates for specific physical activities among individuals five years or older. Data extraction for included articles (n=64) was assessed independently and agreed upon by two authors. A random-effects model was used to calculate participation rates in specific activities for each age group and region. In total 73,304 articles were retrieved and 64 articles representing 47 countries were included in the final meta-analysis. Among adults, walking was the most popular activity in the Americas (18.9%; 95% CI 10.2 to 32.5), Eastern Mediterranean (15.0%; 95% CI 5.8 to 33.6), Southeast Asia (39.3%; 95% CI 0.9 to 98.0) and Western Pacific (41.8%; 95% CI 25.2 to 60.6). In Europe and Africa, soccer (10.0%; 95% CI 6.5 to 15.1) and running (9.3%; 95% CI 0.9 to 53.9), respectively, were top activities. Child and adolescent participation results were highly dependent upon region. American youth team sport participation was high, while youth from the Eastern Mediterranean and Western Pacific were more likely to report participation in lifelong physical activities. Global data for adults reflects a consistent pattern of participation in running and walking. Among all age groups and regions soccer was popular. In children and adolescents, preferences were variable between regions.

Association of physical activity and physical performance with tibial cartilage volume and bone area in young adults

Introduction

Physical activity has been recommended to patients with knee osteoarthritis for improving their symptoms. However, it is still controversial if physical activity has effects on joint structures including cartilage volume. The aim of this study was to describe the associations between physical activity and performance measured 5 years prior and tibial cartilage volume and bone area in young adults.

Methods

Subjects broadly representative of the Australian population (n = 328, aged 31–41 years, female 47.3 %) were selected from the Childhood Determinants of Adult Health study. They underwent T1-weighted fat-suppressed magnetic resonance imaging (MRI) scans of their knees. Tibial bone area and cartilage volume were measured from MRI. Physical activity (measured using long international physical activity questionnaire (IPAQ)) and performance measures (long jump, leg muscle strength, physical work capacity (PWC₁₇₀)) were measured 5 years prior.

Results

In multivariable analyses, total physical activity (min/week) (β: 0.30 mm³, 95 % CI: 0.13,0.47), vigorous (β: 0.54 mm³, 95 % CI: 0.13,0.94), moderate (β: 0.34 mm³, 95 % CI: 0.01,0.67), walking (β: 0.40 mm³, 95 % CI: 0.07,0.72) and IPAQ category (β: 182.9 mm³, 95 % CI: 51.8,314.0) were positively associated with total tibial cartilage volume but not tibial bone area. PWC₁₇₀, long jump and leg muscle strength were positively and significantly associated with both total tibial cartilage volume and total tibial bone area; and the associations with tibial cartilage volume decreased in magnitude but remained significant for PWC₁₇₀ and long jump after further adjustment for tibial bone area.

Conclusion

While tibial bone area is affected only by physical performance, total tibial cartilage volume can be influenced by both physical activity and performance in younger adults. The clinical significance suggests a beneficial effect for cartilage but the bone area association was restricted to performance suggesting other factors rather than physical activity may be important.

Past sporting activity during growth induces greater bone mineral content and enhances bone geometry in young men and women

We aimed to determine the effect of past sporting activity on bone mineral content (BMC), areal bone mineral density (aBMD) in the lumbar spine and proximal femur, and bone geometry of the mid femur in young men and women. We assessed 142 subjects, comprising 79 young men (21.2 ± 0.8 years) and 63 premenopausal young women (21.4 ± 0.6 years). The subjects were classified into three groups, two on the basis of the age of starting to participate in sport [elementary school starters (6-12 years), junior high school to university starters (13-22 years)], and the third group had no participation in sport. We measured BMC and aBMD by dual-energy X-ray absorptiometry (DXA) in the lumbar spine and proximal femur, and bone geometric characteristics of the mid femur by magnetic resonance imaging (MRI), and calculated the osteogenic index (OI) of previous sporting activity. The OI correlated significantly with many MRI-determined measures of bone geometry; DXA-measured BMC and aBMD were effective indicators of previous sporting activity in both sexes. The female elementary school starters had significantly greater femoral mid-diaphyseal perimeters (vs the no-sport group), bone cross-sectional area (vs the 13-22-year-old starters and the no-sport group), and maximum and minimum second moment of area at the mid-diaphysis point of the femur (vs the no-sport group). The OI is a proven practicable and useful index. DXA- and MRI-determined geometric characteristics showed that high-impact, weight-bearing exercise before and in early puberty induces greater total proximal femur BMC and enhances femoral mid-diaphyseal size and shape, and that these benefits persisted in young adult women.

Adolescence physical activity is associated with higher tibial pQCT bone values in adulthood after 28-years of follow-up--the Cardiovascular Risk in Young Finns Study

High peak bone mass and strong bone phenotype are known to be partly explained by physical activity during growth but there are few prospective studies on this topic. In this 28-year follow-up of Cardiovascular Risk in Young Finns Study cohort, we assessed whether habitual childhood and adolescence physical activity or inactivity at the age of 3-18 years were associated with adult phenotype of weight-bearing tibia and the risk of low-energy fractures. Baseline physical activity and data on clinical, nutritional and lifestyle factors were assessed separately for females and males aged 3-6-years (N=395-421) and 9-18-years (N=923-965). At the age of 31-46-years, the prevalence of low-energy fractures was assessed with a questionnaire and several tibial traits were measured with pQCT (bone mineral content (BMC; mg), total and cortical cross-sectional areas (mm(2)), trabecular (for the distal site only) and cortical (for the shaft only) bone densities (mg/cm(3)), stress-strain index (SSI; mm(3), for the shaft only), bone strength index (BSI; mg(2)/cm(4), for the distal site only) and the cortical strength index (CSI, for the shaft only)). For the statistical analysis, each bone trait was categorized as below the cohort median or the median and above and the adjusted odds ratios (OR) were determined. In females, frequent physical activity at the age of 9-18-years was associated with higher adulthood values of BSI, total and cortical areas, BMC, CSI and SSI at the tibia independently of many health and lifestyle factors (ORs 0.33-0.53, P≤0.05; P-values for trend 0.002-0.05). Cortical density at the tibial shaft showed the opposite trend (P-value for trend 0.03). Similarly in males, frequent physical activity was associated with higher values of adult total and cortical areas and CSI at the tibia (ORs 0.48-0.53, P≤0.05; P-values for trend 0.01-0.02). However, there was no evidence that childhood or adolescence physical activity was associated with lower risk of low energy fractures during the follow-up. In conclusion, frequent habitual physical activity in adolescence seems to confer benefits on tibial bone size and geometry in adulthood.

Exercise characteristics influence femoral cross-sectional geometry: a magnetic resonance imaging study in elite female athletes

The associations between mid-femoral cross-sectional geometry and exercise characteristics were investigated in female athletes. The effects on bone geometry for weight-bearing sports with low-to-high-impact were greater than those for non-impact weight-bearing sports, whereas low-impact or high-strain-magnitude/low-strain-rate sports had less of an effect on bone geometry compared with higher-impact sports.

INTRODUCTION

Many previous studies have investigated tibial geometry in athletes; however, few studies have examined the associations between femoral cross-sectional geometry and exercise characteristics. The aim of this study was to investigate these relationships using magnetic resonance imaging (MRI) at the femoral mid-shaft.

METHODS

One hundred and fifty-three female elite athletes, aged 18-34 years, were classified into five groups based on the characteristics of their sports. Sports were considered non-impact (n = 27), low- or moderate-impact (n = 39), odd-impact (n = 38), high-strain-magnitude/low-strain-rate (n = 10), or high-impact (n = 39). Bone geometrical parameters, including cortical area, periosteal perimeter, and moment of inertia (bone strength index), were determined using MRI images.

RESULTS

Higher-impact groups displayed bone expansion, with significantly greater periosteal perimeters, cortical areas (~37.3%), and minimum moments of inertia (I(min,) ~92.3%) at the mid-femur than non- and low-impact groups. After adjusting for age, height, and weight, the cortical area and I(min) of the low-impact and high-strain-magnitude/low-strain-rate groups were also significantly greater than those of the non-impact group.

CONCLUSIONS

Higher-impact sports with high strain rates stimulated periosteal bone formation and improved bone geometry and strength indices at the femoral mid-shaft. Although our results indicate that weight-bearing sports are beneficial even if they are low impact, the effects of lower-impact or high-strain-magnitude/low-strain-rate sports on bone geometry were less pronounced than the effects of higher-impact sports at the femoral mid-shaft.

Combat sports practice favors bone mineral density among adolescent male athletes

The aim of this study was to determine the impact of combat sports practice on bone mineral density (BMD) and to analyze the relationship between bone parameters and anthropometric measurements, bone markers, and activity index (AI). In other words, to detect the most important determinant of BMD in the adolescent period among combat sports athletes. Fifty athletes engaged in combat sports, mean age 17.1±0.2 yr, were compared with 30 sedentary subjects who were matched for age, height, and pubertal stage. For all subjects, the whole-body BMD, lumbar spine BMD (L2-L4), and BMD in the pelvis, arms, and legs was measured by dual-energy X-ray absorptiometry, and anthropometric measurements were evaluated. Daily calcium intake, bone resorption, and formation markers were measured. BMD measurements were greater in the combat sports athletes than in the sedentary group (p<0.01). Weight, body mass index, and lean body mass were significantly correlated with BMD in different sites. Daily calcium consumption lower than daily calcium intake recommended in both athletes and sedentary group. AI was strongly correlated with all BMD measurements particularly with the whole body, legs, and arms. Negative correlations were observed between bone markers and BMD in different sites. The common major predictor of BMD measurements was AI (p<0.0001). AI associated to lean body mass determined whole-body BMD until 74%. AI explained both BMD in arms and L2-L4 at 25%. AI associated to height can account for 63% of the variance in BMD legs. These observations suggested that the best model predicting BMD in different sites among adolescent combat sports athletes was the AI. Children and adolescents should be encouraged to participate in combat sports to maximize their bone accrual.

Physical Activity-Associated Bone Loading During Adolescence and Young Adulthood Is Positively Associated With Adult Bone Mineral Density in Men

Physical activity during growth increases bone mass and strength; however, it remains unclear whether these benefits persist. The purpose of this study was to determine: (a) if bone loading during adolescence (13-18 years) or young adulthood (19-29 years) in men is associated with greater bone mineral density (BMD) in adulthood; (b) if current participation in high-impact activity (ground reaction force>4×body weight) and/or resistance training is associated with greater BMD; and, (c) if continuous participation in a high-impact activity from adolescence to adulthood is associated with greater BMD. Apparently healthy, physically active men aged 30 to 65 years (n=203) participated in this cross-sectional study. Exercise-associated bone loading was estimated based on ground reaction forces of historical physical activity. Current BMD was measured using dual-energy X-ray absorptiometry. Participants were grouped based on current participation in a high-impact activity (n=18), resistance training (n=57), both (n=14), or neither (n=114); groups were compared by two-way analysis of covariance. Bone loading during adolescence and young adulthood were significant, positive predictors of BMD of the whole body, total hip, and lumbar spine, adjusting for lean body mass and/or age in the regression models. Individuals who currently participate in a high-impact activity had greater lumbar spine BMD than nonparticipants. Men who continuously participated in a high-impact activity had greater hip and lumbar spine BMD than those who did not. In conclusion, physical activity-associated bone loading both during and after skeletal growth is positively associated with adult bone mass.

Underweight, overweight, and pediatric bone fragility: impact and management

Skeletal health is modulated by a variety of factors, including genetic makeup, hormonal axes, and environment. Across all ages, extremes of body weight may exert a deleterious effect on bone accretion and increase fracture risk. The incidence of both anorexia nervosa and obesity, each involving extreme alterations in body composition, is rising among youth, and secondary osteoporosis is increasingly being diagnosed among affected children and adolescents. Compared with the elderly, the definition of osteoporosis that stems from any underlying condition differs for the pediatric population and special precautions are required with regard to treatment of young patients. Early recognition and management of both underweight and overweight youth and the accompanying consequences on bone and mineral metabolism are essential for preservation of skeletal health, although prevention of bone loss and optimization of bone mineral accrual remain the most important protective measures.

Exercise during growth and young adulthood is independently associated with cortical bone size and strength in old Swedish men

Previous studies have reported an association between exercise during youth and increased areal bone mineral density at old age. The primary aim of this study was to investigate if exercise during growth was independently associated with greater cortical bone size and whole bone strength in weight-bearing bone in old men. The tibia and radius were measured using both peripheral quantitative computed tomography (pQCT) (XCT-2000; Stratec) at the diaphysis and high-resolution pQCT (HR-pQCT) (XtremeCT; Scanco) at the metaphysis to obtain cortical bone geometry and finite element-derived bone strength in distal tibia and radius, in 597 men, 79.9 ± 3.4 (mean ± SD) years old. A self-administered questionnaire was used to collect information about previous and current physical activity. In order to determine whether level of exercise during growth and young adulthood or level of current physical activity were independently associated with bone parameters in both tibia and radius, analysis of covariance (ANCOVA) analyses were used. Adjusting for covariates and current physical activity, we found that men in the group with the highest level of exercise early in life (regular exercise at a competitive level) had higher tibial cortical cross-sectional area (CSA; 6.3%, p < 0.001) and periosteal circumference (PC; 1.6%, p = 0.011) at the diaphysis, and higher estimated bone strength (failure load: 7.5%, p < 0.001; and stiffness: 7.8%, p < 0.001) at the metaphysis than men in the subgroup with the lowest level of exercise during growth and young adulthood. Subjects in the group with the highest level of current physical activity had smaller tibial endosteal circumference (EC; 3.6%, p = 0.012) at the diaphysis than subjects with a lower current physical activity, when adjusting for covariates and level of exercise during growth and young adulthood. These findings indicate that exercise during growth can increase the cortical bone size via periosteal expansion, whereas exercise at old age may decrease endosteal bone loss in weight-bearing bone in old men.

Marital histories, marital support, and bone density: findings from the Midlife in the United States Study

We examined the association between marital life history and bone mineral density (BMD) in a national sample from the US. In men, being stably married was independently associated with better lumbar spine BMD, and in women, more spousal support was associated with better lumbar spine BMD.

INTRODUCTION

Adult bone mass may be influenced by stressors over the life course. We examined the association between marital life history and bone mineral density (BMD) net socioeconomic and behavioral factors known to influence bone mass. We sought evidence for a gender difference in the association between marital history and adult BMD.

METHODS

We used data from 632 adult participants in the Midlife in the United States Study to examine associations between marital history and BMD, stratified by gender, and adjusted for age, weight, menopausal stage, medication use, childhood socioeconomic advantage, adult financial status, education, physical activity, smoking, and alcohol consumption.

RESULTS

Compared to stably married men, men who were currently divorced, widowed, or separated, men who were currently married but previously divorced, widowed, or separated, and never married men had 0.33 (95% CI: 0.01, 0.65), 0.36 (95% CI: 0.10, 0.83), and 0.53 (95% CI: 0.23, 0.83) standard deviations lower lumbar spine BMD, respectively. Among men married at least once, every year decrement in age at first marriage (under age 25) was associated with 0.07 SD decrement in lumbar spine BMD (95% CI: 0.002, 0.13). In women, greater support from the spouse was associated with higher lumbar spine BMD.

CONCLUSIONS

Our findings suggest that marriage before age 25 and marital disruptions are deleterious to bone health in men, and that marital quality is associated with better bone health in women.

Physical Activity and Bone: May the Force be with You

Physical activity (PA) is thought to play an important role in preventing bone loss and osteoporosis in older people. However, the type of activity that is most effective in this regard remains unclear. Objectively measured PA using accelerometers is an accurate method for studying relationships between PA and bone and other outcomes. We recently used this approach in the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine relationships between levels of vertical impacts associated with PA and hip bone mineral density (BMD). Interestingly, vertical impacts >4g, though rare, largely accounted for the relationship between habitual levels of PA and BMD in adolescents. However, in a subsequent pilot study where we used the same method to record PA levels in older people, no >4g impacts were observed. Therefore, to the extent that vertical impacts need to exceed a certain threshold in order to be bone protective, such a threshold is likely to be considerably lower in older people as compared with adolescents. Further studies aimed at identifying such a threshold in older people are planned, to provide a basis for selecting exercise regimes in older people which are most likely to be bone protective.

Does physical activity in adolescence have site-specific and sex-specific benefits on young adult bone size, content, and estimated strength?

The long-term benefits of habitual physical activity during adolescence on adult bone structure and strength are poorly understood. We investigated whether physically active adolescents had greater bone size, density, content, and estimated bone strength in young adulthood when compared to their peers who were inactive during adolescence. Peripheral quantitative computed tomography (pQCT) was used to measure the tibia and radius of 122 (73 females) participants (age mean ± SD, 29.3 ± 2.3 years) of the Saskatchewan Pediatric Bone Mineral Accrual Study (PBMAS). Total bone area (ToA), cortical density (CoD), cortical area (CoA), cortical content (CoC), and estimated bone strength in torsion (SSIp ) and muscle area (MuA) were measured at the diaphyses (66% tibia and 65% radius). Total density (ToD), trabecular density (TrD), trabecular content (TrC), and estimated bone strength in compression (BSIc ) were measured at the distal ends (4%). Participants were grouped by their adolescent physical activity (PA) levels (inactive, average, and active) based on mean PA Z-scores obtained from serial questionnaire assessments completed during adolescence. We compared adult bone outcomes across adolescent PA groups in each sex using analysis of covariance followed by post hoc pairwise comparisons with Bonferroni adjustments. When adjusted for adult height, MuA, and PA, adult males who were more physically active than their peers in adolescence had 13% greater adjusted torsional bone strength (SSIp , p < 0.05) and 10% greater adjusted ToA (p < 0.05) at the tibia diaphysis. Females who were more active in adolescence had 10% larger adjusted CoA (p < 0.05), 12% greater adjusted CoC (p < 0.05) at the tibia diaphysis, and 3% greater adjusted TrC (p < 0.05) at the distal tibia when compared to their inactive peers. Benefits to tibia bone size, content, and strength in those who were more active during adolescence seemed to persist into young adulthood, with greater ToA and SSIp in males, and greater CoA, CoC, and TrC in females.

Sport-specific association between exercise loading and the density, geometry, and microstructure of weight-bearing bone in young adult men

In this population-based study of 24-year-old men, we have investigated the association between sport-specific exercise loading and different bone parameters. We reveal that the association between exercise loading and bone parameters is sport-specific, indicating that nonspecific resistance exercise does not impact bone density, geometry, or microstructure in young men.

INTRODUCTION

In this cross-sectional study, the association between nonspecific resistive exercise and areal and volumetric bone density, bone geometry, or bone microstructure was investigated in young adult men.

METHODS

A total of 184 male athletes, 24.0 ± 0.6 years of age (mean ± SD), representing nonspecific resistive exercise and soccer (proportion of recreational athletes, 93.4 and 7.7 %, respectively), and 177 nonathletic age-matched controls were measured with dual-energy X-ray absorptiometry. Radius and tibia were measured by peripheral quantitative computed tomography (pQCT) at the diaphysis and by three-dimensional pQCT at the metaphysis.

RESULTS

Men in the nonspecific resistive exercise group had higher grip strength(9.1 % or 0.4 SD) and higher lean mass(5.6 % or 0.5 SD) than those in the nonathletic group(p < 0.01 and p < 0.001, respectively). However, men who participated in nonspecific resistive exercise did not have higher bone density or a more favorable bone microstructure or geometry than their nonathletic referents. In contrast, men playing soccer had higher areal bone mineral density (aBMD) at the femoral neck (19.5 % or 1.2 SD) and lumbar spine (12.6 % or 1.0 SD), as well as larger cortical cross-sectional area (16.4 % or 1.1 SD) and higher trabecular bone volume fraction (14.5 % or 0.9 SD), as a result of increased trabecular number (8.7 % or 0.6 SD) and thickness (5.7 % or 0.4 SD) at the tibia than men in the nonathletic group(p < 0.001).

CONCLUSIONS

Weight-bearing exercise with impacts from varying directions (playing soccer) is associated with aBMD and volumetric BMD, cortical bone geometry, as well as trabecular microstructure of weight-bearing bone. Nonspecific recreational resistance exercise does not appear to be a strong determinant of bone density, geometry, or microstructure in young adult men.

Bone structure and geometry in young men: the influence of smoking, alcohol intake and physical activity

BACKGROUND

The development of osteoporosis is influenced by peak bone mass attained in youth - the influence of lifestyle factors upon which is poorly described, especially amongst males. We sought to address this issue in a large scale study.

METHODS

Hip bone mineral density (dual X-ray absorptiometry, DXA), bone microarchitecture (calcaneal quantitative ultrasound, QUS) and femoral geometry (magnetic resonance imaging, MRI) were characterised in 723 healthy male military recruits (mean ± S.E. age 19.92 ± 0.09 years [range 16-18 years], height 177.67 ± 0.24 cm, weight 73.17 ± 0.37 kg) on entry to UK Army training. Association was sought with prior physical activity, smoking status and alcohol intake.

RESULTS

DXA measures were made in 651, MRI measures in 650, and QUS measures in 572 recruits. Increasing levels of weight-bearing physical activity enhanced periostial bone apposition, increases in both total hip and femoral neck bone mineral density (BMD; p ≤ 0.0001 in both cases), and cortical [p<0.0001] and periostial bone volumes [p=0.016]. Smoking habit was associated with preserved bone geometry, but worse BMD [p=0.0001] and QUS characteristics [p ≤ 0.0005]. Moderate alcohol consumption was associated with greater BMD [p ≤ 0.015].

CONCLUSIONS

Whilst exercise (and perhaps moderate alcohol intake) is beneficial to bone morphometry, smoking is detrimental to bone mineral density in young males notable for the likely short duration of smoking to influence skeletal properties. However, differences in socio-economic status, lifestyle and related environmental factors may to some extent confound our results.

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.

Socioeconomic status over the life-course and adult bone mineral density: the Midlife in the U.S. Study

PURPOSE

Adult bone mass depends on acquisition in childhood and decline in adulthood, and may be influenced by socioeconomic conditions over the entire life course.

METHODS

We examined associations of bone mineral density (BMD) in adulthood with life course socioeconomic status in 729 participants in the Midlife in the United States Biomarker Project, adjusting for age, menopausal transition stage, race, gender, body weight, smoking, physical activity in several life stages, and research site. Primary predictors were a) childhood socioeconomic advantage score (including parental education, self-rated financial status relative to others, not being on welfare), b) adult education level (no college vs. some college vs. college graduate), and c) adult current financial advantage score (including family-adjusted poverty to income ratio, self-assessed current financial situation, having enough money to meet needs, ease in paying bills).

RESULTS

Mean age was 56.9 (range 34-85) years. After adjustment for covariates, childhood socioeconomic advantage and adult education level were positively associated with lumbar spine BMD: 0.27 standard deviations (SD) higher at 90th compared to 10th percentile of childhood advantage score (P=0.009), and 0.24 SD higher in college graduates compared to participants without college education (P=0.01). Adult current financial advantage was not associated with lumbar spine BMD. None of the three socioeconomic indicators was significantly associated with femoral neck BMD.

CONCLUSIONS

Childhood socioeconomic advantage and adult education level were associated with higher adult lumbar spine BMD. Current financial advantage was not associated with BMD. Childhood socioeconomic factors may influence acquisition of lumbar BMD.

Age and sex differences in tibia morphology in healthy adult Caucasians

Variability in peripheral Quantitative Computed Tomography (pQCT) measurement sites limits direct comparisons of results between studies. Further, it is unclear what estimates of bone strength are most indicative of changes due to aging, disease, or interventions. The purpose of this study was to examine age group and sex differences in tibia morphology. Additional purposes of this study were to determine which tibia site or sites are most sensitive for detecting age and sex differences.

METHODS

Self-identifying Caucasian men (n=55) and women (n=59) ages 20-59 years and separated by decades had their non-dominant tibias measured with pQCT (Stratec XCT 3000) at every 10% of the limb length from 5% to 85% (distal to proximal). Volumetric BMD and BMC of the total, cortical and trabecular bone were determined, as well as periosteal (PeriC) and endosteal (EndoC) circumferences, and cortical thickness (CTh).

RESULTS

There were significant (p<0.01) site effects for all BMC, vBMD, PeriC and EndoC measures. Large sex differences (men>women) in Tot.BMC (21-28%) were paralleled by differences in Cort.BMC (21-25%) (p<0.01). Site∗sex interaction effects were significant (p<0.05) for BMC (peak sex difference: 5%, 15%, 25%, 85% sites) and circumference (peak sex difference: 65% site) variables. CTh and total vBMD were lowest (p<0.05) in 50-59 year group, and EndoC was highest in the 50-59 year group. Site∗age interactions existed for Cort.vBMD, Tot.BMC (85% site), and EndoC (25%, 35%, 55%-85% sites). Correcting for bone free lean body mass (BFLBM) greatly reduced sex differences, eliminating sex∗site interaction effects, but sex main effects remained significant. Correcting for BFLBM did not eliminate age effects.

CONCLUSION

The magnitude of age and sex differences in tibia variables varied by measurement site demonstrating the need for standardization of measurement sites.

Habitual levels of vigorous, but not moderate or light, physical activity is positively related to cortical bone mass in adolescents

CONTEXT

The intensity of habitual physical activity (PA) needed to affect skeletal development in childhood is currently unclear.

OBJECTIVE

To examine associations between light PA, moderate PA, and vigorous PA (as assessed by accelerometry), and tibial cortical bone mass (BMC(C)) as measured by peripheral quantitative computed tomography.

DESIGN/SETTING

Cross-sectional analysis based on the Avon Longitudinal Study of Parents and Children.

PARTICIPANTS

A total of 1748 boys and girls (mean age 15.5 yr) participated in the study.

OUTCOME MEASURES

We measured BMC(C), cortical bone mineral density, periosteal circumference, and endosteal circumference by tibial peripheral quantitative computed tomography.

RESULTS

Multivariable models, adjusted for height and other activity levels, indicated vigorous PA was positively related to BMC(C) (P = 0.0001). There was little evidence of a relationship with light PA or moderate PA (both P ≥ 0.7). In path analyses, the relationship between vigorous PA and BMC(C) [0.082 (95% confidence interval [CI]: 0.037, 0.128), P = 0.0004] (SD change per doubling of vigorous PA) was minimally attenuated by adjusting for body composition [0.070 (95% CI: 0.026, 0.115), P = 0.002]. In analyses adjusted for body composition, the relationship between vigorous PA and BMC(C) was explained by the periosteal circumference pathway [0.043 (95% CI: 0.004, 0.082), P = 0.03] and the endosteal circumference adjusted for periosteal circumference pathway [0.031 (95% CI: 0.011, 0.050), P = 0.002], while there was little contribution from the cortical bone mineral density pathway (P = 0.3).

CONCLUSIONS

Vigorous day-to-day PA is associated with indices of BMC(C) and geometry in adolescents, whereas light or moderate PA has no detectable association. Therefore, promoting PA in childhood is unlikely to benefit skeletal development unless high-impact activities are also increased.

Associations of physical activity duration, frequency, and load with volumetric BMD, geometry, and bone strength in young girls

SUMMARY

More efficacious physical activity (PA) prescriptions for optimal bone development are needed. This study showed that PA duration, frequency, and load were all independently associated with bone parameters in young girls. Increased PA duration, frequency, and load are all important osteogenic stimuli that should be incorporated into future PA interventions.

INTRODUCTION

This study evaluated the associations of physical activity (PA) duration, frequency, load, and their interaction (total PA score = duration × frequency × load) with volumetric bone mineral density, geometry, and indices of bone strength in young girls.

METHODS

Four hundred sixty-five girls (aged 8-13 years) completed a past year physical activity questionnaire (PYPAQ) which inquires about the frequency (days per week) and duration (average minutes per session) of leisure-time PA and sports. Load (peak strain score) values were assigned to each activity based on ground reaction forces. Peripheral quantitative computed tomography was used to assess bone parameters at metaphyseal and diaphyseal sites of the femur and tibia of the non-dominant leg.

RESULTS

Correlations across all skeletal sites between PA duration, frequency, load and periosteal circumference (PC), bone strength index (BSI), and strength-strain index (SSI) were significant (p ≤ 0.05), although low (0.10-0.17). A 2.7-3.7% greater PC across all skeletal sites was associated with a high compared to a low PYPAQ score. Also, a high PYPAQ score was associated with greater BSI (6.5-8.7%) at metaphyseal sites and SSI (7.5-8.1%) at diaphyseal sites of the femur and tibia. The effect of a low PYPAQ score on bone geometric parameters and strength was greater than a high PYPAQ score.

CONCLUSIONS

PA duration, frequency, and load were all associated with bone geometry and strength, although their independent influences were modest and site specific. Low levels of PA may compromise bone development whereas high levels have only a small benefit over more average levels.

Positive influence of long-lasting and intensive weight-bearing physical activity on hip structure of young adults

The aim was to analyze the associations between high-intensity and long-lasting weight-bearing sports with hip structure in young adults. One hundred and seventy-two subjects aged 17-28 yr were divided into 4 groups: 40 athlete women (10.2 ± 2.2 h/wk), 30 control women, 67 athlete men (11.4 ± 3.6 h/wk), and 35 control men. The nondominant femur, lumbar spine, and whole body were scanned by dual-energy X-ray absorptiometry to assess bone mineral content (BMC) and bone mineral density (BMD). Hip structure analysis (HSA) software was applied to evaluate cross-sectional area, cross-sectional moment of inertia, and section modulus at the femoral neck, intertrochanter, and femoral shaft regions. All the BMC and BMD values were significantly higher in athletes of both sexes compared with controls (p < 0.05). Most of the hip structural parameters were significantly higher (p < 0.05) in athletes compared with controls. Most of the differences were maintained after adjustments for height, weight, and calcium intake. Positively significant correlations were observed between HSA parameters and physical activity variables in both sexes (r > 0.32; p < 0.05). Partial correlation suggested that the hours of practice appeared to have a greater influence than the years of practice on hip bone geometry. These results suggest that external mechanical loading is a strong determinant of hip bone structure when weight-bearing physical activity is commenced before puberty and maintained during adulthood.

Bone health and the female athlete triad in adolescent athletes

Peak bone mass (PBM) is a negative predictor of osteoporosis and lifelong fracture risk. Because osteoporosis is such a prevalent disease with life-threatening consequences, it is important to try to maximize PBM. Adolescence is a critical period for bone acquisition. This article discusses some of the differences in male and female skeletal development and modifiable factors that enhance bone accrual in this age group, particularly in athletes. Hormonal influences, effects of physical activity, and nutritional contributions are included, with a focus on the adolescent athlete. Emphasis is placed on the importance of appropriate energy availability in this age group. We also review prevention and treatment strategies for the female athlete triad (ie, the inter-relationship of decreased energy availability, menstrual irregularity, and low bone density) in adolescents and athletic women. Recommendations for maximizing bone density in both male and female adolescents are discussed.

Trabecular and cortical bone separately assessed at radius with a new ultrasound device, in a young adult population with various physical activities

The aim was to evaluate a new ultrasound device in a young adult population and to assess its reproducibility via comparison to DXA measurements and geometrical measurements from high-resolution radiographs. Ninety-three subjects aged between 20 and 51 years were recruited and divided into four groups according to their gender and physical activity status: 22 male athletes, 19 male controls, 21 female athletes, and 31 female controls. Ultrasonic measurements were assessed by the prototype LD-100 (Oyo Electric Co., Kyoto, Japan) on the dominant distal radius. Attenuation in the radius (dB), cortical bone thickness (mm), radius thickness (mm), mass density of cancellous bone (mg/cm(3)), and elasticity (GPa) of cancellous bone were obtained. BMD was measured by DXA at the dominant distal radius. Radius images were obtained with a direct high-resolution digital X-ray device (BMA, D(3)A Medical Systems), and radius and cortical thicknesses were estimated using a specific software (ImageJ, Bethesda, USA), in an area site-matched with LD-100. There was a significant positive correlation between site-matched BMD measurement and LD-100 parameters (p<0.004), X-ray radius thickness, and LD-100 parameters except elasticity (p<0.05, r>0.32), X-ray cortical thickness and LD-100 attenuation and cortical thickness (p<0.01). A significantly higher attenuation, cortical and radius thicknesses were found in athletes compared to controls (p<0.05). The radius thickness measured on radiographs was significantly higher in athletes versus controls in both sexes, and cortical thickness was significantly higher in male athletes versus controls. These data suggest a positive influence of physical activity on bone cortical measurements. This study also confirmed the particular interest of bone assessment by ultrasound.

Bone loading during young adulthood predicts bone mineral density in physically active, middle-aged men

BACKGROUND

Physical activity during growth induces skeletal adaptations that increase bone strength; however, it remains unclear whether these benefits persist into middle age.

OBJECTIVE

We sought to determine if bone loading during adolescence (ages 13-18 years) or young adulthood (ages 19-29 years) in men is associated with greater bone mineral density (BMD) and reduced risk of low bone density in adulthood. We also sought to determine if participation in high-impact activities (ie, those that produce a ground reaction force [GRF] > 4 times the individual's body weight] during adolescence and/or young adulthood has a lasting positive effect on adult BMD.

METHODS

Eighty-six, apparently healthy, physically active men (aged 30-60 years) participated in this cross-sectional study. Bone loading during adolescence, young adulthood, and adulthood were calculated based on GRFs of the reported physical activities. Whole body, lumbar spine, total hip, and femoral neck BMD were assessed using dual-energy x-ray absorptiometry (DXA). Multiple linear regression was used to examine relationships between BMD and bone loading, including body weight and/or age as covariates; logistic regression was used to predict low bone density for age. Participants were grouped based on participation in high-impact activity (never [n = 42], adolescence only [n = 19], or both adolescence and young adulthood [n=23]), and BMDs were compared.

RESULTS

Bone loading during young adulthood, but not adolescence, was a significant positive predictor of adult BMD, with the full models explaining 33.4%, 31.7%, 44.6%, and 50.6% of the variance in whole body, lumbar spine, total hip, and femoral neck BMD, respectively. Ten participants (11.6%) had low bone density for age based on z scores of the hip or spine. Body weight and lean body mass, but not bone loading, were associated with reduced risk of low bone density for age. Individuals who participated in high-impact activity during both adolescence and young adulthood had greater BMD at all measured sites compared with those participated only during adolescence.

CONCLUSION

The results of the study support a lifelong exercise prescription for bone health to preserve the skeletal benefits of activity derived from activity during adolescence and young adulthood.

Association of physical activity with trabecular microstructure and cortical bone at distal tibia and radius in young adult men

CONTEXT

The relationship between physical activity, trabecular microstructure, and cortical geometry in weight-bearing and non-weight-bearing bone has not previously been studied in men.

OBJECTIVE

The aim of this study was to investigate whether present (type and amount) and previous duration of physical activity were associated with trabecular microstructure and cortical cross-sectional area (CSA) in weight-bearing bone in young men.

DESIGN AND SETTING

This was a cross-sectional, population-based study.

PARTICIPANTS

Participants included a cohort of 829 Swedish men between 22.8 and 25.7 yr old (24.1 +/- 0.6 yr, mean +/- SD).

MAIN OUTCOME MEASURES

Several microstructural trabecular and cortical traits were assessed with high-resolution three-dimensional peripheral quantitative computed tomography at distal tibia and radius. A standardized questionnaire was used to collect information about physical activity amount (hours per year), duration (years), and type (strain score 0-3, based on ground reaction forces).

RESULTS

Men with the highest physical activity strain score had higher tibial trabecular bone volume fraction (13.9Delta%) and trabecular number (12.7%) than men with the lowest strain score (P < 0.001). Men in the group with the longest duration of physical activity had higher tibial cortical CSA (16.1%) than the sedentary men (P < 0.001). Inclusion of all physical activity variables in a linear regression model revealed that strain score independently predicted trabecular bone volume fraction, and trabecular number (P < 0.001) and that duration of previous physical activity independently predicted cortical CSA (P < 0.001) of the tibia.

CONCLUSIONS

In this large cohort of young men, the degree of mechanical loading due to type of physical activity was predominantly associated with trabecular microstructure, whereas duration of previous physical activity was mainly related to parameters reflecting cortical bone size in weight-bearing bone.

Increased circulating adiponectin levels and decreased leptin/soluble leptin receptor ratio throughout puberty in female ballet dancers: association with body composition and the delay in puberty

INTRODUCTION

Ballet dancers (BDs) have a negative energy balance related to physical training that results in alterations in body composition, sexual development, and adipokine secretion. Our aims were to study anthropometric parameters, body composition, and their relationship with adipokines throughout pubertal development.

SUBJECTS AND METHODS

We carried out a prospective follow-up study of 22 female Caucasian BDs (Tanner II stage) followed throughout puberty. Nutritional status was determined by measurement of height, weight, and body mass index (BMI). We calculated growth velocity, bone maturity, and body composition at Tanner stages II, III, and V by dual energy X-ray absorptiometry. Circulating leptin, adiponectin, and soluble leptin receptor (sObR) levels were determined.

RESULTS

BDs presented a delay in skeletal maturation during puberty, without affectation of final height. Energy intake was deficient according to their physical exercise, and they had a delay of 1 year in the mean age of menarche. Leptin levels were decreased, whereas sObR and adiponectin levels were increased throughout puberty. The percentage of trunk fat, total fat mass, and fat of the extremities was decreased throughout the study period (P<0.01). Lean mass was increased in the lower extremities, and bone mineral density was normal.

CONCLUSION

A negative energy balance together with maintained physical exercise induced modifications in body composition in BDs. Changes in leptin and adiponectin levels appear to be more related to total fat content than to BMI. Furthermore, the onset and delayed progress of puberty may be related with an inadequate energy balance due to increased exercise.

Peripubertal estrogen levels and physical activity affect femur geometry in young adult women

The growing skeleton is particularly responsive to exercise around the time of puberty, suggesting a possible role for estrogen in mechanical adaptation in young women. We assessed femoral neck strength index at age 17 in young women with varying adolescent physical activity levels and E2 levels in the first 3 years after menarche. The results indicate that both E2 levels in the first year after menarche and adolescent physical activity are positively associated with bone strength in young adulthood, such that hormone levels may modify human osteogenic responses to exercise.

INTRODUCTION

It is well established that physical activity contributes to bone strength in young females, but less is known about how peripubertal estrogen affects skeletal responses to exercise.

METHODS

We used data from 84 participants in the Penn State Young Women's Health Study to test the prediction that young women who (1) had higher E2 levels during the first year after menarche or (2) were more physically active in adolescence will have greater bone strength at the end of adolescence. Subjects were divided into tertiles of physical activity and of E2 level in the first, second, and third postmenarchal years, and femoral strength was calculated from dual-energy X-ray absorptiometry scans of the proximal femur using hip structure analysis.

RESULTS

At age 17, subjects with the highest E2 levels in year 1 after menarche had 5-14% greater strength in the narrow neck and intertrochanteric region, and the most active subjects had 10-11% greater strength in the femoral narrow neck vs. less active girls.

CONCLUSIONS

This study suggests that both physical activity and peripubertal estrogen have important influences on young adult bone strength and that hormone levels may be mediators of human osteogenic responses to exercise.