Bone mineral density of adolescent female tennis players and nontennis players

Development of Upper-Extremity Morphological Asymmetries in Male and Female Elite Youth Tennis Players: A Longitudinal Study

PURPOSE

This 2-year longitudinal study examined the development of upper-extremity bone mineral density (BMD), bone mineral content (BMC), and lean mass (LM) asymmetry magnitudes in male and female youth tennis players.

METHODS

Dominant and nondominant upper-extremity BMD, BMC, and LM values of 49 male and 31 female players were measured yearly using dual X-ray absorptiometry. From these values, asymmetry magnitudes were calculated and expressed as a percentage. Maturity offset was estimated using anthropometric measurements. Linear mixed effect models examined the development of BMD, BMC, and LM asymmetry magnitudes according to players' maturity offset, sex, and training volume.

RESULTS

Adjusted for sex and training volume, a 1-year increment in maturity offset was associated with a significant increase in BMD (1.3% [2.2%]; P < .001) and BMC (0.6% [2.4%]; P = .011) asymmetry magnitudes. Male players displayed significantly higher LM asymmetry magnitudes (Δ3.2% [8.4%]; P = .002) compared with their female counterparts. Training volume was not significantly associated with asymmetry magnitude development.

CONCLUSION

In contrast to LM, male and female youth tennis players' upper-extremity bones are still responsive to mechanical loading with a significant increase in BMD and BMC asymmetry magnitudes according to maturity offset.

The Impact of the Characteristics of Exercise on The Risk of Breast Cancer Instructions

Background:

Exercise seems to protect from breast cancer (BC) and this protection is likely mediated through weight control during menopause. Considering that night work is associated with higher risk for BC.

Objective:

The aim of this study was to examine the possible relation of BC risk to daytime or nighttime hours of exercise.

Methods:

The material was taken from primary elements of a doctoral thesis at the Department of Midwifery, University of West Attica that examines the impact of the characteristics of exercising on BC. The data were obtained from relevant questionnaires filled in at a big private hospital, following a relevant permit of the scientific committee, and adjusted Google Forms, ensuring anonymity.

Results:

Almost 3 times more women without a history of BC were exclusively exercising during the daytime compared to the ones with a history of BC who were exclusively exercising during the nighttime (40 vs 15). On the contrary, a smaller number of women without a history of BC were exclusively exercising during the nighttime compared to the ones with a history of BC who were exclusively exercising during the nighttime (17 vs 20) (odds ratio >3 with a confidence interval >1 to >7.5 and p<0.05).

Conclusion:

It seems that the protective impact of exercising on BC is mitigated when the exercise is performed exclusively during night hours.

Whole-body morphological asymmetries in high-level female tennis players: A cross‑sectional study

This cross-sectional study aimed to examine the degree of whole-body morphological asymmetries in female tennis players. Data were collected in 19 high-level female tennis players (21.3 ± 3.4 years). Based on anthropometric measurements (upper arm, lower arm, wrist, upper leg and lower leg circumferences as well as elbow and knee widths) and dual x-ray absorptiometry research scans (bone mineral density (BMD), bone mineral content (BMC), lean mass (LM), fat mass (FM) as well as humerus, radio-ulnar, femur and tibia bone lengths), within-subject morphological asymmetries for both upper (dominant vs. non-dominant) and lower (contralateral vs. ipsilateral) extremities were examined. Upper arm (p = 0.015), lower arm (p < 0.001) and wrist circumferences (p < 0.001), elbow width (p = 0.049), BMD (p < 0.001), BMC (p < 0.001), LM (p = 0.001), humerus (p = 0.003) and radio-ulnar bone length (p < 0.001) were all greater in the dominant upper extremity. BMC (p < 0.001) and LM (p < 0.001) were greater in the contralateral lower extremity, whereas FM (p = 0.028) was greater in the ipsilateral lower extremity. This is the first study to report significant side-to-side differences in both upper and lower extremities in high-level female tennis players.

Track and Field Practice and Bone Outcomes among Adolescents: A Pilot Study (ABCD-Growth Study)

Background

Osteoporosis is considered a public health problem with high worldwide prevalence. One approach to prevention is through the promotion of physical activity, especially exercise, during adolescence.

Methods

This study compared bone variables in different body segments in adolescents according to participation in track and field. The study included 34 adolescents (22 boys), of whom 17 were track and field athletes and 17 were control subjects. Bone mineral density (BMD, g/cm²) and bone mineral content (BMC, g) were analyzed using dual energy X-ray absorptiometry (total body stratified by body segments). Peak height velocity was used to estimate somatic maturation.

Results

Athletes had higher BMD (P=0.003) and BMC (P=0.011) values in the lower limbs and higher whole body BMD (P=0.025) than the control group. However, when adjusted for confounding factors, the difference was not maintained. The groups had similar lean soft tissue values (P=0.094). Training overload was positively correlated with BMD in the upper limbs (r=0.504; 95% confidence interval, 0.031-0.793). Although track and field athletes had higher BMD and BMC values in the lower limbs, these differences were not significant when adjusted for confounding factors.

Conclusions

Track and field participation in adolescence appears to influence BMD and BMC in lower limbs, and fat-free mass seems to mediate this effect. Also, higher training loads were found to be positive for bone health in upper limbs.

Physical exercise associated with improved BMD independently of sex and vitamin D levels in young adults

Purpose

Young men and women accrue the majority of their bone mass in their teens and twenties, where their bone mass peaks (PBM), yet little is known about the roles of physical exercise, vitamin D levels and bone mineral density (BMD) near PBM.

Methods

To comparatively examine the effect of physical exercise and two vitamin D levels (insufficient s-25[OH]D <50 nmol/L and sufficient s-25[OH]D >80 nmol/L) on the BMD measured at the femoral neck, total hip (bilaterally) and the lumbar spine (L2–L4) in male and female participants approaching PBM.

Results

The insufficient s-25[OH]D group, median age 21.6 (19.8–22.8) years, and BMI 24.2 ± 5.0 kg/m² had BMD 0.10 (0.03, 0.17) g/cm² (p = 0.008) lower at all DXA-scan sites compared to the sufficient s-25[OH]D group, median age 19.5 (19.0–22.3) years, and BMI of 22.6 ± 1.8 kg/m². Exercise was positively associated with the BMD at all DXA-scan sites (p_trend = 0.0001) and with equal benefit; there was no interaction between exercise and the DXA-scan site (p = 0.09). The male participants did not have a systematically higher BMD than the female participants for all scan sites; only for hips total and femoral neck bilaterally, while it was equal at the lumbar spine.

Conclusion

The BMD in young healthy adults is associated with physical exercise, independent of sex and s-25[OH]D status. A sufficient s-25[OH]D status was systematically associated with a higher BMD for all levels of exercise. For both sexes and vitamin D levels exercise was equally positively associated with BMD.

Risk Factors for Low Bone Mineral Density in Institutionalized Individuals with Developmental Disabilities

BACKGROUND

Persons with intellectual/developmental disabilities (IDD) are exposed to several factors, which have been determined as risks for osteoporosis. Many of these individuals are non-ambulatory, resulting in lack of weight bearing activity, which is well established as a major contributor to bone loss. The purpose of this study was to investigate risk factors for low bone mineral density (BMD) in persons with IDD residing in residential facilities.

METHODS

This cross-sectional study was conducted at an Intermediate Care Facility for individuals with Intellectual and Developmental Disabilities (ICF/IDD). Medical records data were used from 69 individuals, including heal scan T-scores, nutritional, pharmacologic and other risk factors. Chi-Square analysis was used to determine relationships between the variables.

RESULTS

BMD measures were not significantly associated with age, gender, height, weight, or BMI for this population (P > 0.05). The association between BMD diagnoses and DSM-IV classification of mental retardation approached significance (P = 0.063). A significant association was found with anti-seizure medication (P = 0.009).

CONCLUSION

Follow-up studies should focus on how supplementation and medication changes may or may not alter BMD. Persons with IDD are experiencing longer life expectancies, and therefore, studies ascertaining information on diseases associated with this aging population are warranted.

Top 10 research questions related to physical activity and bone health in children and adolescents

Evidence strongly supports a positive, causal effect of physical activity on bone strength and suggests long-term benefits of childhood physical activity to the prevention of osteoporosis. The contribution of healthy bone development in youth is likely to be as important to fracture prevention as the amount of late adulthood bone loss. Families, schools (particularly physical education), and communities are key settings for health promotion focused on bone-enhancing physical activity. However, little research has explored the topic of health promotion and physical education as they pertain to bone health, so best practices are not known. Based on our understanding of the literature, we present the top 10 research questions in health promotion and physical education that should be answered to advance bone-enhancing physical activity in children and adolescents.