Low bone mineral density is two to three times more prevalent in non-athletic premenopausal women than in elite athletes: a comprehensive controlled study

Cross-sectional associations between accelerometer-measured physical activity and hip bone mineral density: the Tromsø Study 2015-2016

Positive associations between physical activity and bone health have been found in population-based studies, however, mostly based on self-reported physical activity. Therefore, we investigated the association between accelerometer-measured physical activity, measured in steps per day and minutes of moderate to vigorous physical activity (MVPA) per day, and total hip areal BMD (aBMD) measured by DXA in a general population, utilizing multiple regression models. The study participants, 1560 women and 1177 men aged 40-84 yr, were part of the seventh survey of the Tromsø Study (2015-2016). In both genders, we found a positive association between the number of daily steps and aBMD adjusted for age, BMI, and smoking status (P < .001). In women, an increase of 1000 steps per day was associated with 0.005 g/cm2 higher aBMD. For men, a polynomial curve indicated a positive association with aBMD up to 5000 steps per day, plateauing between 5000 and 14 000 steps, and then increasing again. Additionally, MVPA duration was positively associated with aBMD in both women (P < .001) and men (P = .004) when adjusted for age, BMI, and smoking status. Specifically, each 60-min increase in daily MVPA was associated with 0.028 and 0.023 g/cm2 higher aBMD in women and men, respectively. Despite positive associations, the clinical impact of physical activity on aBMD in this general population of adults and older adults was relatively small, and a large increase in daily MVPA might not be achievable for most individuals. Therefore, further longitudinal population-based studies incorporating device-based measures of physical activity could add more clarity to these relationships.

Bone Mineral Density in Mountain, Road Cyclists and Untrained Controls: Exercise, Diet and Hormones

Purpose: The aim of the study was to compare bone mineral density (BMD) in the lumbar spine (LSBMD) and the femoral neck (FBMD) in male road cyclists (RC n = 39), mountain cyclists (MC n = 30) and controls (C n = 27) and to determine the factors associated with BMD in the same group of participants. Methods: BMD, fat mass (FM) and fat-free mass (FFM) were measured using DXA. Calcium intake (Cal), exercise energy expenditure (EEE) and energy availability (EA) were assessed using self-reported questionnaires. Samples for circulating hormones were also obtained. VO2max was estimated by a cycloergometric test. Results: After adjustment for body mass, in cyclists LSBMD (RC 0.98 ± 0.12; MC 0.98 ± 0.10 g/cm2) was significantly lower than in C (1.11 ± 0.10; p < .001), while FBMD resulted in no significant difference in cyclists compared to C (p = 0.213). EA (kcal/FFM/day) was different in cyclists and in C (p < .05). In C, EEE and EA were positively associated with LSBMD (R = 0.561, R = 0.656, respectively, p < .01), whereas only EA was associated with FBMD (R = 0.554, p < .05); a positive association between EA and FBMD was found in MC (R = 0.464, p < .05). A negative relationship between VO2max and LSBMD in RC (R = -0.418, p < .05) and a positive one between EEE and LSBMD in MC were found (R = 0.605, p < .001). CaI, free testosterone and cortisol were unrelated to BMD. Conclusion: Both the RC and MC had lower LSBMD than C, whereas no difference was found between the two groups of cyclists. The factors associated with BMD are manifold, vary in relation to the measurement site and are likely different in RC, MC and C.

The effect of overweight or obesity on osteoporosis: A systematic review and meta-analysis

BACKGROUND

Osteoporosis and obesity are closely related, and the relationships between different types of obesity and osteoporosis are inconsistent.

OBJECTIVE

Our objective was to summarize earlier data concerning the association between osteoporosis and obesity (general and central), and to compare the impacts of these two obesity indicators on osteoporosis.

METHODS

From inception to May 2021, a comprehensive search in electronic bibliographic databases was conducted, and the search was updated in December 2021, July 2022 and June 2023. The data were independently extracted and evaluated by two investigators from epidemiological studies that reported the impact of obesity on the odds of incident osteoporosis.

RESULTS

There were 24 studies included in the final analysis when it came to general obesity measured by body mass index (BMI). Individuals with overweight and obesity had decreased odds of osteoporosis (odds ratio (OR), 0.451, 95% confidence intervals (CIs): 0.366-0.557). Sensitivity analyses showed that both overweight and obesity were decreased odds of osteoporosis, with reductions of 48.6% and 70.1%, respectively (OR, 0.514, 95% CI: 0.407-0.649; OR, 0.299, 95% CI: 0.207-0.433). Conversely, individuals classified as underweight were found to have higher odds of osteoporosis (OR, 2.540, 95% CI: 1.483-4.350). In term of central obesity, the final analysis consisted of 7 studies. No significant association was observed between central obesity and osteoporosis (OR, 0.913, 95% CI: 0.761-1.096).

CONCLUSIONS

General overweight and obesity were associated with lower odds of developing osteoporosis, whereas underweight was associated with higher odds. However, central obesity did not show a significant association with osteoporosis. These findings underscore the importance of considering the impact of obesity on osteoporosis. Further research is necessary to reinforce the evidence and validate our findings.

High-altitude exposure decreases bone mineral density and its relationship with gut microbiota: Results from the China multi-ethnic cohort (CMEC) study

BACKGROUND

Geographic altitude is a potent environmental factor for human microbiota and bone mineral density. However, little evidence exists in population-based studies with altitude diversity ranges across more than 3000 m. This study assessed the associations between a wide range of altitudes and bone mineral density, as well as the potential mediating role of microbiota in this relationship.

METHODS

A total of 99,556 participants from the China Multi-Ethnic Cohort (CMEC) study were enrolled. The altitude of each participant was extracted from global Shuttle Radar Topography Mission (SRTM) 4 data. Bone mineral density was measured by calcaneus quantitative ultrasound index (QUI). Stool samples were collected for 16S rRNA gene sequencing (n = 1384). The metabolites of gut microbiota, seven kinds of short-chain fatty acids (SCFAs), were detected by gas chromatography-mass spectrometry (GC-MS, n = 128). After screening, 73,974 participants were selected for the "altitude-QUI" analysis and they were placed into the low-altitude (LA) and high-altitude (HA) groups. Additionally, a subgroup (n = 1384) was further selected for the "altitude-microbiota-QUI" analysis. Multivariate linear regression models and mediation analyses were conducted among participants.

RESULTS

A significant negative association between high-altitude and QUI was obtained (mean difference = -0.373 standard deviation [SD], 95% confidence interval [CI]: -0.389, -0.358, n = 73,974). The same negative association was also observed in the population with microbiota data (mean difference = -0.185 SD, 95%CI: -0.360, -0.010, n = 1384), and a significant mediating effect of Catenibacteriumon on the association between altitude and QUI (proportion mediated = 25.2%, P = 0.038) was also noticed. Additionally, the acetic acid, butyric acid, and total amount of seven SCFAs of the low-altitude group were significantly higher than that of the high-altitude group (P < 0.05).

CONCLUSION

High-altitude exposure may decrease bone mineral density in adults, thus increasing the risk of osteoporosis. The modulation of gut microbiota may be a potential strategy for alleviating the decrease of bone mineral density.

The Effect of Professional Sports Participation on Bone Content and Density in Elite Female Athletes

Background: The role of exercise in osteoporosis prevention has been proven. Nevertheless, there is no consensus about the types of sports, especially at professional levels. Non-impact sports such as swimming may have a negative effect or no effect. Objectives: Thus, the present study aimed to compare the effect of different sports on bone mineral content (BMC) and bone mineral density (BMD) of elite female athletes. Methods: This was a cross-sectional study consisting of 48 athletes in five groups of long-distance running, volleyball, basketball, swimming (n = 12 for each), and ten control subjects. For measuring the lumbar spine (L2 - L4) and proximal femur (femoral neck, trochanter, and Ward’s triangle), the dual-energy X-ray absorptiometry (DEXA) method was applied. Results: Indicated that the running, basketball, and volleyball groups had a significantly higher lumbar spine and proximal femur BMD than the swimming and control groups (P < 0.05). Running resulted in significantly higher lumbar spine BMC compared to volleyball, basketball, swimming, and control groups, respectively (P < 0.01), while basketball had higher proximal femur BMC than running and controls (P < 0.01). The Z-score of the lumbar spine in the running was significantly higher than in basketball, swimming, and controls (P < 0.05), while basketball had a significantly higher femur neck Z-score than volleyball, running, and controls (P < 0.001). Finally, the swimmers had significantly higher Z-scores in the lumbar and the proximal femur than non-athletes (P < 0.001). Conclusions: Although all sports are effective for improving the bone health, the swimmers had much better bone status than non-athletes, while the sports of long-distance running and basketball were more efficient than others; therefore, a combination of endurance and jumping exercises seems to be the best way to prevent osteoporosis.

Methodology Review: A Protocol to Audit the Representation of Female Athletes in Sports Science and Sports Medicine Research

Female-specific research on sports science and sports medicine (SSSM) fails to mirror the increase in participation and popularity of women's sport. Females have historically been excluded from SSSM research, particularly because their physiological intricacy necessitates more complex study designs, longer research times, and additional costs. Consequently, most SSSM practices are based on research with men, despite potential problems in translation to females due to sexual dimorphism in biological and phenotypical parameters as well as differences in event characteristics (e.g., race distances/durations). Recognition that erroneous extrapolations may hamper the efforts of females to maximize their athletic potential has created an impetus to acknowledge and readdress the sex disparity in SSSM research. To direct the priorities for future research, it is prudent to first develop a comprehensive understanding of the gaps in current knowledge by systematically "auditing" the literature. By conducting audits of the literature to highlight underdeveloped topics or identify potential problems with the quality of research, this information can then be used to expediently direct new research activities. This paper therefore presents a standardized audit methodology to establish the representation of female athletes in subdisciplines of existing SSSM research, including a template for reporting the results of key metrics. This standardized audit process will enable comparisons over time and between research subdisciplines. This working guide provides an important step toward achieving sex equity across SSSM research, with the eventual goal of providing evidence-based recommendations specific to the female athlete.

A 15-year follow-up study of hip bone mineral density and associations with leisure time physical activity. The Tromsø Study 2001–2016

Aims

The aim was to investigate the long-term association between leisure time physical activity and hip areal bone mineral density (aBMD), in addition to change in hip aBMD over time, in 32–86 years old women and men.

Methods

Data were retrieved from the 2001, 2007–2008, and 2015–2016 surveys of the Tromsø Study, a longitudinal population study in Norway. Leisure time physical activity was assessed by the four-level Saltin-Grimby Physical Activity Level Scale which refers to physical exertion in the past twelve months. Hip aBMD was assessed by Dual-Energy X-ray Absorptiometry. Linear Mixed Model analysis was used to examine long-term associations between physical activity and hip aBMD (n = 6324). In addition, the annual change in hip aBMD was analyzed in a subsample of 3199 participants.

Results

Physical activity was significantly and positively associated with total hip aBMD in the overall cohort (p<0.005). Participants who reported vigorous activity had 28.20 mg/cm2 higher aBMD than those who were inactive (95% CI 14.71; 41.69, controlled for confounders), and even light physical activity was associated with higher aBMD than inactivity (8.32 mg/cm2, 95% CI 4.89; 11.76). Associations between physical activity and femoral neck aBMD yielded similar results. Hip aBMD decreased with age in both sexes, although more prominently in women. From 2001 to 2007–2008, aBMD changed by –5.76 mg/cm2 per year (95% CI –6.08; –5.44) in women, and –2.31 mg/cm2 (95% CI –2.69; –1.93), in men. From 2007–2008 to 2015–2016, the change was –4.45 mg/cm2 per year (95% CI –4.84; –4.06) in women, and –1.45 mg/cm2 (95% CI –1.92; –0.98) in men.

Conclusions

In this cohort of adult men and women, physical activity levels were positively associated with hip aBMD in a dose-response relationship. Hip aBMD decreased with age, although more pronounced in women than men.

Risk of Low Energy Availability in National and International Level Paralympic Athletes: An Exploratory Investigation

(1) Background: The purpose of this study was to examine the symptoms of low energy availability (LEA) and risk of relative energy deficiency in sport (RED-S) symptoms in para-athletes using a multi-parameter approach. (2) Methods: National level para-athletes (n = 9 males, n = 9 females) completed 7-day food and activity logs to quantify energy availability (EA), the LEA in Females Questionnaire (LEAF-Q), dual energy X-ray absorptiometry (DXA) scans to assess bone mineral density (BMD), and hormonal blood spot testing. (3) Results: Based on EA calculations, no athlete was at risk for LEA (females < 30 kcal·kg⁻¹ FFM·day⁻¹; and males < 25 kcal·kg⁻¹ FFM·day⁻¹; thresholds for able-bodied (AB) subjects). Overall, 78% of females were “at risk” for LEA using the LEAF-Q, and 67% reported birth control use, with three of these participants reporting menstrual dysfunction. BMD was clinically low in the hip (<−2 z-score) for 56% of female and 25% of male athletes (4) Conclusions: Based on calculated EA, the risk for RED-S appears to be low, but hormonal outcomes suggest that RED-S risk is high in this para-athlete population. This considerable discrepancy in various EA and RED-S assessment tools suggests the need for further investigation to determine the true prevalence of RED-S in para-athlete populations.

Sport and pelvic floor dysfunction in male and female athletes: A scoping review

AIMS

The aims of the present scoping review were to systematically map and summarize findings to identify any study that reported epidemiological data on pelvic floor dysfunction (PFD) among male and female athletes.

METHODS

Six medical databases were searched up to March 2020. No language, study design, and publication type restrictions were applied. Additional studies were identified through gray literature and the reference lists of articles were screened. The results were presented numerically and thematically.

RESULTS

A total of 4358 records were identified with an initial search. A hundred studies met the criteria for inclusion. The number of studies published annually increased over the years. Cross-sectional studies (n = 62), urinary incontinence (n = 64), multiple sports (n = 58), and female athletes (n = 83) are the most investigated study design, condition, sport, and population, respectively. Only 12 studies explored PFD in the male population. Authors focused selectively on elite athletes in 21 studies.

CONCLUSIONS

This is the first scoping review to provide a comprehensive overview of the topic. The major gaps in the literature include studies focused on male participants, other PFD (e.g., anal incontinence, pelvic organ prolapse, and pelvic pain), with appropriate study design. This review may be useful to raise awareness of the issue among clinicians and stakeholders in sport and it may represent a starting point for future research.

Physical health and symptoms of relative energy deficiency in female fitness athletes

INTRODUCTION

Competing in aesthetic sports increases the risk of low energy availability and associated health impairments. Fitness physique sport is a popular, but understudied aesthetic sport. We evaluated health and symptoms of relative energy deficiency in sport (RED-s) in female fitness athletes (FA) and female references (FR) during a competitive season.

METHODS

Totally, 25 FA and 26 FR, mean (SD) age of 28.9 (5.7), were included. Assessments were at baseline (T1), 2-weeks pre-competition (T2), and 1-month post-competition (T3), by dual-energy x-ray absorptiometry scan, indirect calorimetry, diet registration, The Low Energy Availability in Females Questionnaire, The Beck Depression Inventory, and Eating Disorder Examination Questionnaire (EDE-Q).

RESULTS

A history of eating disorders was reported by 35% FA and 12% FR. There were no between-group differences at T1, besides less mean (99% CI) fat mass (FM) of 3.1 kg (-0.4, 6.5) in FA (P = .02). At T2, FA had lower BW of 6.7 kg (-12.0, -1.3), fat mass of -9.0 kg (-12.5, -5.5), and resting heart rate of -8.0 beats per minute (-14.5, -1.5) compared to FR (P ≤ .006). FA reduced resting metabolic rate by -191 kcal (-11, -371) and increased symptoms of gastrointestinal dysfunction (GD) by 1.4 points (0.3, 2.5) and prevalence of amenorrhea from 8% to 24%, (P < .003). At T3, there was a between-group difference in fat mass, and a high number of FA with amenorrhea and GD.

CONCLUSION

Manifestation of symptoms of RED-s, some with persistence one-month post-competition, raises concern for the health of FA and those complying with the fit body ideal.

Associations between exercise, bone mineral density, and body composition in adolescents with anorexia nervosa

OBJECTIVE

To identify the effect of duration of weight-bearing exercise and team sports participation on bone mineral density (BMD) and body composition among adolescents with anorexia nervosa (AN).

METHOD

We retrospectively reviewed electronic medical records of all patients 9-20 years old with a DSM-5 diagnosis of AN evaluated by the Stanford Eating Disorders Program (1997-2011) who underwent dual-energy X-ray absorptiometry.

RESULTS

A total of 188 adolescents with AN were included (178 females and 10 males). Using multivariate linear regression, duration of weight-bearing exercise (B = 0.15, p = 0.005) and participation in team sports (B = 0.53, p = 0.001) were associated with higher BMD at the hip and team sports (B = 0.39, p = 0.006) were associated with higher whole body BMC, controlling for covariates. Participation in team sports (B = - 1.06, p = 0.007) was associated with greater deficits in FMI Z-score. LBMI Z-score was positively associated with duration of weight-bearing exercise (B = 0.10, p = 0.018) and may explain the relationship between exercise and bone outcomes.

CONCLUSION

Duration of weight-bearing exercise and team sports participation may be protective of BMD at the hip and whole body BMC, while participation in team sports was associated with greater FMI deficits among adolescents with AN.

LEVEL OF EVIDENCE

Level V, descriptive retrospective study.

The interactions of physical activity, exercise and genetics and their associations with bone mineral density: implications for injury risk in elite athletes

Low bone mineral density (BMD) is established as a primary predictor of osteoporotic risk and can also have substantial implications for athlete health and injury risk in the elite sporting environment. BMD is a highly multi-factorial phenotype influenced by diet, hormonal characteristics and physical activity. The interrelationships between such factors, and a strong genetic component, suggested to be around 50-85% at various anatomical sites, determine skeletal health throughout life. Genome-wide association studies and case-control designs have revealed many loci associated with variation in BMD. However, a number of the candidate genes identified at these loci have no known associated biological function or have yet to be replicated in subsequent investigations. Furthermore, few investigations have considered gene-environment interactions-in particular, whether specific genes may be sensitive to mechanical loading from physical activity and the outcome of such an interaction for BMD and potential injury risk. Therefore, this review considers the importance of physical activity on BMD, genetic associations with BMD and how subsequent investigation requires consideration of the interaction between these determinants. Future research using well-defined independent cohorts such as elite athletes, who experience much greater mechanical stress than most, to study such phenotypes, can provide a greater understanding of these factors as well as the biological underpinnings of such a physiologically "extreme" population. Subsequently, modification of training, exercise or rehabilitation programmes based on genetic characteristics could have substantial implications in both the sporting and public health domains once the fundamental research has been conducted successfully.

Low Energy Availability Is Difficult to Assess but Outcomes Have Large Impact on Bone Injury Rates in Elite Distance Athletes

We aimed to (a) report energy availability (EA), metabolic/reproductive function, bone mineral density, and injury/illness rates in national/world-class female and male distance athletes and (b) investigate the robustness of various diagnostic criteria from the Female Athlete Triad (Triad), Low Energy Availability in Females Questionnaire, and relative energy deficiency in sport (RED-S) tools to identify risks associated with low EA. Athletes were distinguished according to benchmarks of reproductive function (amenorrheic [n = 13] vs. eumenorrheic [n = 22], low [lowest quartile of reference range; n = 10] versus normal testosterone [n = 14]), and EA calculated from 7-day food and training diaries (< or >30 kcal·kg^-1 fat-free mass·day^-1). Sex hormones (p < .001), triiodothyronine (p < .05), and bone mineral density (females, p < .05) were significantly lower in amenorrheic (37%) and low testosterone (40%; 15.1 ± 3.0 nmol/L) athletes, and bone injuries were ∼4.5-fold more prevalent in amenorrheic (effect size = 0.85, large) and low testosterone (effect size = 0.52, moderate) groups compared with others. Categorization of females and males using Triad or RED-S tools revealed that higher risk groups had significantly lower triiodothyronine (female and male Triad and RED-S: p < .05) and higher number of all-time fractures (male Triad: p < .001; male RED-S and female Triad: p < .01) as well as nonsignificant but markedly (up to 10-fold) higher number of training days lost to bone injuries during the preceding year. Based on the cross-sectional analysis, current reproductive function (questionnaires/blood hormone concentrations) appears to provide a more objective and accurate marker of optimal energy for health than the more error-prone and time-consuming dietary and training estimation of EA. This study also offers novel findings that athlete health is associated with EA indices.

Differences in bone mineral density between normal-weight children and children with overweight and obesity: a systematic review and meta-analysis

OBJECTIVE

This study examines the differences in bone mineral density between normal-weight children and children with overweight or obesity.

METHODS

A systematic review and meta-analysis of observational studies (published up to 22 June 2016) on the differences in bone mineral density between normal-weight children and overweight and obese children was performed. Results were pooled when possible and mean differences (MDs) were calculated between normal-weight and overweight and normal-weight and obese children for bone content and density measures at different body sites.

RESULTS

Twenty-seven studies, with a total of 5,958 children, were included. There was moderate and high quality of evidence that overweight (MD 213 g; 95% confidence interval [CI] 166, 261) and obese children (MD 329 g; 95%CI [229, 430]) have a significantly higher whole body bone mineral content than normal-weight children. Similar results were found for whole body bone mineral density. Sensitivity analysis showed that the association was stronger in girls.

CONCLUSIONS

Overweight and obese children have a significantly higher bone mineral density compared with normal-weight children. Because there was only one study included with a longitudinal design, the long-term impact of childhood overweight and obesity on bone health at adulthood is not clear.

Bone Health in Athletes

CONTEXT

The health of the skeletal system is important for athletes young and old. From the early benefits of exercise on bones to the importance of osteoporosis prevention and treatment, bone health affects the ability to be active throughout life.

EVIDENCE ACQUISITION

PubMed articles dating from 1986 to 2016 were used for the review. Relevant terms such as keywords and section titles of the article were searched and articles identified were reviewed for relevance to this article.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Levels 1 through 4 evidence included.

RESULTS

There is strong evidence that exercise benefits bone health at every age and is a critical factor in osteoporosis prevention and treatment. Vitamin D, calcium, and hormones play vital roles in ensuring optimal bone health. When there is an imbalance between exercise and nutrition, as seen in the female athlete triad, bone health is compromised and can lead to bone stress injuries and early osteoporosis. Both of these can lead to morbidity and lost time from training and competition. Thus, early recognition and appropriate treatment of the female athlete triad and other stress fracture risk factors are vital to preventing long-term bone health problems.

CONCLUSION

To optimize bone health, adequate nutrition, appropriate weightbearing exercise, strength training, and adequate calcium and vitamin D are necessary throughout life.

Current and past menstrual status is an important determinant of femoral neck geometry in exercising women

Menstrual status, both past and current, has been established as an important determinant of bone mineral density (BMD) in young exercising women. However, little is known regarding the association between the cumulative effect of menstrual status and indices of bone health beyond BMD, such as bone geometry and estimated bone strength.

PURPOSE

This study explores the association between cumulative menstrual status and indices of bone health assessed using dual-energy x-ray absorptiometry (DXA), including femoral neck geometry and strength and areal BMD (aBMD), in exercising women.

METHODS

101 exercising women (22.0±0.4years, BMI 21.0±0.2kg/m(2), 520±40min/week of self-reported exercise) participated in this cross-sectional study. Women were divided into three groups as follows based on their self-reported current and past menstrual status: 1) current and past regular menstrual cycles (C+P-R) (n=23), 2) current and past irregular menstrual cycles (C+P-IR) (n=56), 3) and current or past irregular cycles (C/P-RIR) (n=22). Current menstrual status was confirmed using daily urinary metabolites of reproductive hormones. DXA was used to assess estimates of femoral neck geometry and strength from hip strength analysis (HSA), aBMD, and body composition. Cross-sectional moment of inertia (CSMI), cross-sectional area (CSA), strength index (SI), diameter, and section modulus (Z) were calculated at the femoral neck. Low CSMI, CSA, SI, diameter, and Z were operationally defined as values below the median. Areal BMD (g/cm(2)) and Z-scores were determined at the lumbar spine, femoral neck, and total hip. Low BMD was defined as a Z-score<-1.0. Chi-square tests and multivariable logistic regression were performed to compare the prevalence and determine the odds, respectively, of low bone geometry, strength, and aBMD among groups.

RESULTS

Cumulative menstrual status was identified as a significant predictor of low femoral neck CSMI (p=0.005), CSA (p≤0.024), and diameter (p=0.042) after controlling for confounding variables. C+P-IR or C/P-RIR were four to eight times more likely to exhibit low femoral neck CSMI or CSA when compared with C+P-R. Lumbar spine aBMD and Z-score were lower in C+P-IR when compared with C+P-R (p≤0.003). A significant association between menstrual group and low aBMD was observed at the lumbar spine (p=0.006) but not at the femoral neck or total hip (p>0.05). However, after controlling for confounding variables, cumulative menstrual status was not a significant predictor of low aBMD.

CONCLUSION

In exercising women, the cumulative effect of current and past menstrual irregularity appears to be an important predictor of lower estimates of femoral neck geometry, as observed by smaller CSMI and CSA, which may serve as an another means, beyond BMD, by which menstrual irregularity compromises bone strength. As such, evaluation of both current and past menstrual status is recommended to determine potential risk for relatively small bone geometry at the femoral neck.

Associação de força e nível de atividade física à densidade mineral óssea na pós-menopausa

INTRODUÇÃO: o exercício físico atua melhorando a densidade mineral óssea DMO por gerar deformidades nesse tecido e estimular remodelação.OBJETIVO: verificar a associação entre força muscular e nível de atividade física à densidade mineral óssea DMO utilizando testes de força de bíceps, de sentar e levantar, dinamometria de mãos, história pregressa de atividade física e nível de atividade física, avaliado pelo pedômetro com a DMO em mulheres na pós-menopausa.MÉTODOS: estudo transversal, descritivo que mensurou a densidade mineral óssea pela absorção de dupla energia de raios X DXA da coluna lombar L1-L4, fêmur e antebraços em 62 mulheres saudáveis no pós-menopausa, com média de 56,82 ± 4,02 anos de idade. Foi aplicado questionário para atividade física pregressa e realizada contagem diária de passos pedômetro. A força muscular foi medida pelos testes de dinamometria de mãos, de 30 segundos de bíceps bilateral e de sentar e levantar da cadeira em 30 segundos. Realizou-se registro alimentar de três dias para mensuração da ingestão diária de cálcio e vitamina D.RESULTADOS: os indivíduos apresentaram altos níveis de atividade física, porém baixa ingestão diária de cálcio e vitamina D. Não foi verificada diferença estatisticamente significativa entre força muscular nos dois grupos estudados, com DMO diminuída e DMO normal. O grupo com DMO diminuída apresentou maior número de passos diários e menor peso quando comparado com o grupo com DMO normal. Foram observadas várias correlações positivas de baixa magnitude, embora significantes, entre a densitometria e a força muscular p < 0,50.CONCLUSÃO: os autores descreveram risco cinco vezes e meia maior em mulheres não praticantes de atividade física da adolescência até a idade adulta e de apresentarem redução da DMO em comparação com as mulheres que apresentaram DMO normal.

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.

Bone geometry according to menstrual function in female endurance athletes

Athletes have higher bone mineral density (BMD) relative to nonathletes. In amenorrheic athletes BMD may be compromised by estrogen deficiency, but it is unknown whether this is accompanied by structural differences. We compared femoral neck bone geometry and density of a-/oligomenorrheic athletes (AAs), eumenorrheic athletes (EAs), and eumenorrheic controls (ECs). We recruited 156 women: (68 endurance athletes and 88 controls). Femoral neck BMD, section modulus (Z), and width were measured using dual-energy X-ray absorptiometry. Menstrual function was assessed by questionnaire and classified as EA (≥10 periods/year) or AA (≤9 periods/year): 24 athletes were AA and 44 EA. Femoral neck BMD was significantly higher in EA than AA (8 %, difference) and EC (11 % difference): mean [SE] 1.118 [0.015], 1.023 [0.020] and 0.999 [0.014] g cm(-2), respectively; p < 0.001. Z was significantly higher in EA than EC (11 % difference): EA 667 [19], AA 625 [21], and EC 592 [10] cm(3); p < 0.001. Femoral neck width did not differ between groups. All differences persisted after adjustment for height, age, and body mass. The higher femoral neck Z and BMD in athletes, despite similar width, may indicate that exercise-related bone gains are endosteal rather than periosteal. Athletes with amenorrhea had smaller increments in bone mass rather than structural adaptation. The maintained femoral neck width in controls may be an adaptive mechanism to conserve bone strength in bending despite inactivity-related bone decrement.

Female athlete triad syndrome in the high school athlete

Female sports participation at the high school level has significantly increased since the 1970s. Physical activity in females has numerous positive benefits, including improved body image and overall health. Unfortunately, a select population of exercising females may experience symptoms related to the "female athlete triad," which refers to the interrelationships among energy availability, menstrual function, and bone mineral density. Clinically, these conditions can manifest as disordered eating behaviors, menstrual irregularity, and stress fractures. Athletes with conditions related to the triad are distributed along a spectrum between optimal health and disease and may not experience all conditions simultaneously. Previous research related to the triad has primarily focused on collegiate and elite athletes. However, mounting evidence demonstrates that the triad is present in the high school population. High school athletes should be assessed for triad components at preparticipation physicals. In addition, parents, coaches, and health care professionals should be educated and informed about the female athlete triad syndrome. In the presence of triad symptoms, further evaluation and treatment by a multidisciplinary team is strongly recommended for the athlete.

The female athlete triad and endothelial dysfunction

A tremendous increase in the number of female athletes of all ages and abilities has occurred in the past 35 years. In general, sports and athletic competition produce healthier and happier women. However, explosion in participation has revealed clear gender-specific injuries and medical conditions unique to the female athlete. This article focuses on the latest advances in our knowledge of the female athlete triad and the relationship between athletic-associated amenorrhea and endothelial dysfunction. Treatment of vascular dysfunction with folic acid is also discussed.

A Systematic Review of Bone Health in Cyclists

Context:

Low bone mineral density (BMD) is a serious public health problem. Osteoporotic fractures are associated with low bone mass, occurring frequently in the hip and spine. Previous studies have demonstrated a positive relationship between BMD and weightbearing exercise but not a similar positive relationship with nonweightbearing exercise. There is concern that cycling, a weight-supported sport, does not benefit bone health.

Objective:

To systematically review the evidence suggesting that cyclists have impaired bone health at the femoral neck and lumbar spine.

Data Sources:

Articles in PubMed, Cochrane Library, and CINAHL were identified in December 2009 What is the start date for the search?based on the following terms and combinations: bicycling, bone density, cyclist.

Study Selection:

Thirteen studies satisfied inclusion criteria: 2 prospective studies (level of evidence 2b) and 11 cross-sectional studies (level of evidence 2c).

Data Extraction:

Data included sample size, demographics, description of cycling and control criteria, and BMD (g/cm²) at the lumbar spine, femoral neck, and hip.

Results:

Two prospective studies showed a decrease in femoral neck, total hip, or lumbar spine BMD in cyclists over the study period. Four cross-sectional studies compared cyclists with sedentary controls, and 3 found cyclists’ lumbar spine and femoral neck BMD similar to that of controls, whereas 1 found cyclists’ BMD to be lower than that of controls. Seven cross-sectional studies compared cyclists with active controls: 2 found no differences in femoral neck and lumbar spine BMD between cyclists and controls; 4 found that cyclists had lower lumbar spine BMD than did active controls, including runners; and 1 reported a trend toward lower lumbar spine BMD in cyclists versus controls.

Conclusions:

There is concerning but inconsistent, limited-quality disease-oriented evidence—primarily from cross-sectional data—indicating that cyclists may be at risk for low bone mass, particularly at the lumbar spine. Additional longitudinal controlled intervention trials are needed.

The female athlete

Over time, women have become more extensively involved in athletic programs. The female athlete presents a unique challenge to sports medicine in general. Although specific types of injuries are the same as in the male athlete, the female athlete is at higher risk for some of these injuries. Injuries may be sport specific, but gender-related injuries are also related to morphologic and physiologic differences between the male and female athlete. This article reviews some of the differences between the male and female athlete and focuses on a few prominent injuries or risks related specifically to the woman athlete.

DXA surrogates for visceral fat are inversely associated with bone density measures in adolescent athletes with menstrual dysfunction

OBJECTIVE

Lean mass is associated with bone mineral density (BMD) in athletes, attributable to the anabolic pull of muscle on bone. Fat mass is also important, and subcutaneous fat positively and visceral fat negatively correlates with BMD in obese adolescents. The contribution of regional body composition to low BMD in amenorrheic athletes (AA) has not been elucidated. We hypothesized that in adolescent athletes (runners), BMD is associated positively with total fat (surrogate for subcutaneous fat) and lean mass, and inversely with percent trunk fat and trunk-to-extremity fat ratio (surrogates for visceral fat).

DESIGN

Cross-sectional study.

SUBJECTS AND METHODS

We examined BMD and body composition using dual energy X-ray absorptiometry (DXA) in 21 AA and 19 eumenorrheic athletes (EA) (12-18 years) (runners). We report total hip and height-adjusted BMD [lumbar bone mineral apparent density (LBMAD) and whole body bone mineral content/height (WBBMC/Ht)].

RESULTS

AA had lower BMD than EA. Lean mass was less strongly associated with hip BMD in AA than EA; fat mass was positively associated with LBMAD in EA. Percent trunk fat and trunk-to-extremity fat ratio were inversely associated with lumbar and WB measures in AA. In a regression model, lean and fat mass were positively, and percent trunk fat and trunk-to-extremity fat ratio negatively associated with LBMAD and WBBMC/Ht for all athletes, even after controlling for serum estradiol.

CONCLUSIONS

DXA surrogates for visceral fat are inversely associated with bone density in athletes.

Physiologic and behavioral indicators of energy deficiency in female adolescent runners with elevated bone turnover

BACKGROUND

Female adolescent runners have an elevated prevalence of low bone mass for agemdashan outcome that may be partially due to inadequate energy intake.

OBJECTIVE

The objective was to evaluate diet, menstrual history, serum hormone concentrations, and bone mass in female adolescent runners with normal or abnormal bone turnover.

DESIGN

Thirty-nine cross-country runners (age: 15.7 plusmn 0.2 y) participated in the study, which included a 7-d dietary assessment with the use of a food record and daily 24-h dietary recalls; serum measures of insulin-like growth factor I, estradiol, leptin, parathyroid hormone, progesterone, triiodothyronine, 25-hydroxycholecalciferol, bone-specific alkaline phosphatase (BAP), and cross-linked C-telopeptides of type I collagen (CTX); an evaluation of height, weight, bone mass, and body composition with the use of dual-energy X-ray absorptiometry; and a questionnaire to assess menses and sports participation. Age- and sex-specific BAP and CTX concentrations of at least the 97th percentile and no greater than the third percentile, respectively, were considered abnormal.

RESULTS

All abnormal BAP and CTX concentrations fell within the elevated ( ge 97%) range. Runners with an elevated bone turnover (EBT) (n = 13) had a lower body mass, fewer menstrual cycles in the past year, lower estradiol and 25-hydroxycholecalciferol concentrations, and a higher prevalence of body mass index lt 10% for age, vitamin D insufficiency, amenorrhea, and low bone mass. Girls with EBT consumed less than the recommended amounts of energy and had a higher prevalence of consuming lt 1300 mg Ca than did those with normal bone turnover.

CONCLUSIONS

Runners with EBT had a profile consistent with energy deficiency. Nutritional support to increase energy, calcium intake, and 25-hydroxycholecalciferol concentrations may improve bone mineral accrual in young runners with EBT. This trial was registered at clinicaltrials.gov as NCT01059968.

Cross-sectional evidence of suppressed bone mineral accrual among female adolescent runners

We aimed to evaluate patterns of bone mineral accrual among a cross-sectional sample of female adolescent runners and girls participating in a nonendurance running sport. One-hundred and eighty-three interscholastic competitive female athletes (age 16.0 +/- 0.1 years), 93 endurance runners and 90 nonrunners, completed a menstrual and sports history questionnaire, had their height and weight measured, and underwent a dual-energy X-ray absorptiometry scan for the measurements of body composition and bone mass. For the majority of analyses, the girls were separated into four groups according to their age (13 to 14 years, 15 years, 16 years, and 17 to 18 years). Runners' height, weight, body mass index (BMI), percent body fat, lean tissue mass, number of menstrual cycles in the past year, and months of participation in a non-lean-build/variable-impact-loading sport were significantly lower than mean values for nonrunners. Although bone mass rose at all sites in the nonrunners between the ages of 13 to 14 years and 17 to 18 years, no such increase was noted in the runners. Runners compared with nonrunners exhibited significantly lower body weight and height-adjusted total body and lumbar spine bone mineral content (BMC) values and lower bone mineral density (BMD) Z-score values among the older (16 years and/or 17 to 18 years) but not younger (13 to 14 years and/or 15 years) age groups. These findings suggest that the runners, in contrast to the nonrunners, exhibited a suppressed bone mineral accrual pattern, which supports the notion that female adolescent endurance runners may be at risk for inadequate bone mass gains and thus a low peak BMD.

Injuries and medical issues in synchronized Olympic sports

Spectators of the Olympic Games can enjoy a wide variety of sports, including strength, team, timed, endurance, and artistic sports. In the Olympic program, there are two synchronized events: synchronized diving and synchronized swimming. The precision of the synchronization of the athlete's movements and skills is an added feature of entertainment. Synchronized athletes have additional training requirements to perfect the synchronization of their skills. The physical demands on the athlete from the repetition of training required for the perfection of synchronization result in injuries unique to these sports. Although both traumatic and overuse injuries occur, overuse injuries are more common. As these disciplines are artistic, judged sports, these athletes also are susceptible to eating disorders and the female athlete triad. This article reviews the training regimen of these athletes and outlines the injuries and health concerns that are common in the synchronized sports.

History of amenorrhoea compromises some of the exercise-induced benefits in cortical and trabecular bone in the peripheral and axial skeleton: a study in retired elite gymnasts

BACKGROUND

Female gymnasts frequently present with overt signs of hypoestrogenism, such as late menarche or menstrual dysfunction. The objective was to investigate the impact of history of amenorrhoea on the exercise-induced skeletal benefits in bone geometry and volumetric density in retired elite gymnasts.

SUBJECTS AND METHODS

24 retired artistic gymnasts, aged 17-36 years, who had been training for at least 15 h/week at the peak of their career and had been retired for 3-18 years were recruited. They had not been engaged in more than 2 h/week of regular physical activity since retirement. Former gymnasts who reported history of amenorrhoea ('AME', n=12: either primary or secondary amenorrhoea) were compared with former gymnasts ('NO-AME', n=12) and controls ('C', n=26) who did not report history of amenorrhoea. Bone mineral content (BMC), total bone area (ToA) and total volumetric density (ToD) were measured by pQCT at the radius and tibia (4% and 66%). Trabecular volumetric density (TrD) and bone strength index (BSI) were measured at the 4% sites. Cortical area (CoA), cortical thickness (CoTh), medullary area (MedA), cortical volumetric density (CoD), stress-strain index (SSI) and muscle and fat area were measured at the 66% sites. Spinal BMC, areal BMD and bone mineral apparent density (BMAD) were measured by DXA.

RESULTS

Menarcheal age was delayed in AME when compared to NO-AME (16.4+/-0.5 years vs. 13.3+/-0.4 years, p<0.001). No differences were detected between AME and C for height-adjusted spinal BMC, aBMD and BMAD, TrD and BSI at the distal radius and tibia, CoA at the proximal radius, whereas these parameters were greater in NO-AME than C (p<0.05-0.005). AME had lower TrD and BSI at the distal radius, and lower spinal BMAD than NO-AME (p<0.05) but they had greater ToA at the distal radius (p<0.05).

CONCLUSION

Greater spinal BMC, aBMD and BMAD as well as trabecular volumetric density and bone strength in the peripheral skeleton were found in former gymnasts without a history of menstrual dysfunction but not in those who reported either primary or secondary amenorrhoea. History of amenorrhoea may have compromised some of the skeletal benefits associated with high-impact gymnastics training.

Bone mass and geometry of the tibia and the radius of master sprinters, middle and long distance runners, race-walkers and sedentary control participants: a pQCT study

Mechanical loading is thought to be a determinant of bone mass and geometry. Both ground reaction forces and tibial strains increase with running speed. This study investigates the hypothesis that surrogates of bone strength in male and female master sprinters, middle and long distance runners and race-walkers vary according to discipline-specific mechanical loading from sedentary controls. Bone scans were obtained by peripheral Quantitative Computed Tomography (pQCT) from the tibia and from the radius in 106 sprinters, 52 middle distance runners, 93 long distance runners and 49 race-walkers who were competing at master championships, and who were aged between 35 and 94 years. Seventy-five age-matched, sedentary people served as control group. Most athletes of this study had started to practice their athletic discipline after the age of 20, but the current training regime had typically been maintained for more than a decade. As hypothesised, tibia diaphyseal bone mineral content (vBMC), cortical area and polar moment of resistance were largest in sprinters, followed in descending order by middle and long distance runners, race-walkers and controls. When compared to control people, the differences in these measures were always >13% in male and >23% in female sprinters (p<0.001). Similarly, the periosteal circumference in the tibia shaft was larger in male and female sprinters by 4% and 8%, respectively, compared to controls (p<0.001). Epiphyseal group differences were predominantly found for trabecular vBMC in both male and female sprinters, who had 15% and 18% larger values, respectively, than controls (p<0.001). In contrast, a reverse pattern was found for cortical vBMD in the tibia, and only few group differences of lower magnitude were found between athletes and control people for the radius. In conclusion, tibial bone strength indicators seemed to be related to exercise-specific peak forces, whilst cortical density was inversely related to running distance. These results may be explained in two, non-exclusive ways. Firstly, greater skeletal size may allow larger muscle forces and power to be exerted, and thus bias towards engagement in athletics. Secondly, musculoskeletal forces related to running can induce skeletal adaptation and thus enhance bone strength.

Implications of diminished ovarian reserve (DOR) extend well beyond reproductive concerns

OBJECTIVES

To investigate whether a diagnosis of diminished ovarian reserve (DOR) in premenopausal years has adverse implications for skeletal health and quality of life.

DESIGN

This was a cross-sectional study of infertile, albeit healthy, mid-reproductive-age women (younger than 42 y) attending an academic infertility practice.

RESULTS

Eighty-nine women with varying causes of infertility were prospectively enrolled. Serum (cycle d 1-3) was collected for markers of ovarian reserve, bone metabolism, testosterone, and free androgen index. Bone mineral density (BMD) was assessed and categorized as low if the Z score was less than -1.0). Infertile women with DOR (n = 28) demonstrated significantly higher serum follicle-stimulating hormone levels (P < 0.001), lower müllerian-inhibiting substance (MIS) levels (P < 0.001), smaller ovarian dimensions (P < 0.05), lower testosterone levels (P = 0.035), lower free androgen index (P = 0.019), and enhanced bone metabolism (P = 0.003); although the prevalence of low BMD was higher in women with DOR who were younger than 41, this relationship was not of statistical significance (P = 0.106). Women younger than 41 years of age with DOR were significantly more likely to manifest disturbed sleep (P = 0.049) and acknowledge dissatisfaction with sexual intimacy (P = 0.004) compared with those with infertility and normal ovarian reserve. After adjustment for potential confounders, a diagnosis of DOR was significantly associated with low BMD, increased bone turnover, sexual dissatisfaction, and disturbed sleep.

CONCLUSIONS

Our data suggest that DOR unmasked in the context of infertility evaluation has adverse implications for a woman's well-being that extend well beyond the thus far appreciated reproductive concerns. A decline in ovarian hormones, specifically estrogen and testosterone, concomitant with DOR may be hypothesized as a mechanism that can explain the observed multisystem ramifications of DOR including increased bone turnover, low BMD, sexual distress, and disturbed sleep.

Prevalence of and traits associated with low BMD among female adolescent runners

PURPOSE

Identify the prevalence of and traits that may increase the risk of low bone mineral density (BMD) among 93 female adolescent competitive endurance runners.

METHODS

Participants were 93 high school runners, ages 13-18 yr, from southern California. Eating attitudes and behaviors were assessed using the Eating Disorder Examination Questionnaire (EDE-Q). Menstrual and sports participation history were evaluated using an interviewer-assisted, self-report questionnaire. Bone mineral density (BMD) of the spine (L1-L4), total hip, and total body were measured by dual-energy x-ray absorptiometry. The -2 and -1 BMD age-matched, gender-specific z-score cutoffs were used to categorize girls as having low bone mass for age.

RESULTS

Among the female runners, 11.8% and 28% met the -2 and -1 BMD z-score cutoffs, respectively, whereas 25.8% reported menstrual irregularity (MI). Total hip BMD, lumbar spine BMD, and lumbar spine BMD z-score were significantly lower in runners with MI after adjusting for body mass index (BMI) and lean tissue mass. Runners that participated in five or more compared with three seasons of endurance running exhibited a significantly lower total body and lumbar spine BMD z-score after adjusting for BMI, lean tissue mass, and number of menstrual cycles in the past year. Multiple regression analysis indicated that MI, participation in five or more seasons of endurance running, BMI, and lean tissue mass were independent predictors of low BMD.

CONCLUSION

Female adolescent endurance runners may represent a population with an increased risk of low bone mass. Future studies are necessary to further understand the factors contributing to low bone mass in young runners and to identify behavioral strategies that will promote optimal bone mineral accumulation during the adolescent years.

Disability in patients with chronic patellofemoral pain syndrome: a randomised controlled trial of VMO selective training versus general quadriceps strengthening

This study was a prospective single blind randomised controlled trial to compare the effects of rehabilitation with emphasis on retraining the vastus medialis (VMO) component of the quadriceps femoris muscle and rehabilitation with emphasis on general strengthening of the quadriceps femoris muscles on pain, function and Quality of Life in patients with patellofemoral pain syndrome (PFPS). Patients with PFPS (n=69) were recruited from a hospital orthopaedic clinic and randomised into three groups: (1) physiotherapy with emphasis on selectively retraining the VMO (Selective); (2) physiotherapy with emphasis on general strengthening of the quadriceps femoris muscles (General); and (3) a no-treatment control group (Control). The three groups were then compared before and after an eight-week rehabilitation period. The Selective and General groups demonstrated statistically significant and 'moderate' to 'large' effect size reductions in pain when compared to the Control group. Both the Selective and General groups displayed statistically significant and 'moderate' and 'large' effect size improvements in subjective function and Quality of Life compared to the Control group. Knee flexion excursion during the stance phase of gait, demonstrated that there were no statistical significant differences and only 'trivial' to 'small' effect size differences between the Selective or General groups and the Control group. A large number of PFPS patients can experience significant improvements in pain, function and Quality of Life, at least in the short term, with quadriceps femoris rehabilitation, with or without emphasis on selective activation of the VMO component. Both approaches would seem acceptable for rehabilitating patients with PFPS. It may be appropriate to undertake exercises involving selective activation of the vastus medialis early in the rehabilitation process, however, clinicians should not overly focus on selective activation before progressing rehabilitation, especially in more chronic cases with significant participation restrictions.

Female high-school varsity athletics: an opportunity to improve bone mineral density

The present study investigated whether moderate, organized physical activity during high school has a positive residual effect on bone mineral density (BMD) in 30-35-year-old females. Seventy-three female former high-school varsity athletes and 67 self-reported low-activity age-matched controls completed a collegiate women's health survey and participated in a one-time clinical visit with bone scan. Lumbar (L1-L4) spine BMD, total hip BMD, percentage body fat, age at menarche, history of amenorrhea, family history of osteoporosis, college alcohol consumption, number of high school varsity seasons, as well as current nutritional intake (including calcium), number of weekly weight training sessions, and caloric expenditure were assessed. Using a saturated linear regression model, current percentage body fat and number of high school seasons predicted 22% of the observed variation in total hip BMD and 25% of the observed variation of lumbar (L1-L4) spine BMD (P<0.001). High school athletes were more likely to be frequent adult exercisers (P<0.001). Athletic participants were more likely to have denser hip and spine bones than low-activity controls. Results suggest that participation in high school athletics is associated with greater BMD. Additionally, the varsity athletes continued to exercise frequently in their early 30s.

The Female Athlete Triad and Cardiovascular Dysfunction

In the past 35 years, a significant increase has occurred in sports participation by women. An estimated 3 million girls and young women compete in American high school sports. Women who participate in sports and fitness programs are generally healthier and have higher self-esteem. However, an increase has also been seen in gender-specific injuries and medical problems. The female athlete triad is a syndrome of separate but interrelated conditions of disordered eating, amenorrhea, and osteoporosis. Athletic amenorrhea is known to have a hormonal profile similar to menopause characterized by decreased circulating estrogens. Menopause is known to be associated with osteoporosis and accelerated cardiovascular disease. Although enhanced risk for cardiovascular disease is theoretically possible, it has not been explored in the young athletic population. Premature cardiovascular disease first manifests as endothelial dysfunction, which can be examined noninvasively with ultrasound. This article discusses disordered eating, amenorrhea, osteoporosis, and the potential for heightened cardiovascular risk in young athletic women.

The female football player, disordered eating, menstrual function and bone health

Most female football players are healthy. However, recent findings from our studies on Norwegian female elite athletes also show that football players are dieting and experiencing eating disorders, menstrual dysfunction and stress fractures. Dieting behaviour and lack of knowledge of the energy needs of the athlete often leads to energy deficit, menstrual dysfunction and increased risk of bone mass loss. Although dieting, eating disorders and menstrual dysfunction are less common than in many other sports, it is important to be aware of the problem as eating disorders in female athletes can easily be missed. Therefore, individuals, including the players themselves, coaches, administrators and family members, who are involved in competitive football, should be educated about the three interrelated components of the female athlete triad (disordered eating, menstrual dysfunction and low bone mass), and strategies should be developed to prevent, recognise and treat the triad components.

Low lumbar spine bone mineral density in both male and female endurance runners

There have been many reports of low bone mineral density (BMD) in female endurance runners. Although there have been several reports of low BMD in male runners, it is unclear how comparable the problem is to that in females. We compared BMD between male and female endurance runners and with a reference population. One hundred and nine endurance runners (65 females, 44 males) aged 19-50 years participated and had been training regularly for at least 3 years (32-187.2 km week(-1)) in events from 3 km to the marathon. BMD was measured at the lumbar spine (L2-L4) and hip by DXA. A questionnaire assessed training and menstrual status. Lumbar spine T scores were similar in male and female runners (-0.8 (0.8) versus -0.8 (0.7); f = 0.015; P = 0.904) as were total hip T scores (0.6 (7.9) versus 0.5 (9.2); f = 0.192; P = 0.662). The proportion of male runners with low lumbar spine BMD (<-1.0) (n = 16 from 44) compared to that of females (n = 27 from 65) (P = 0.675). Males had lower spine T scores than eumenorrhoeic females (-0.8 (0.7) versus -0.4 (0.7); f = 5.169; P = 0.03). There were moderate negative correlations between weekly running distance and lumbar spine BMD in males and females (r(2) = 0.267; 0.189; P < 0.001), independent of menstrual status in females (r(2) = 0.192; P < 0.001). Lumbar spine but not hip T scores were greater in runners who participated in resistance training at least twice-a-week (male: -0.4 versus -1.1; female: -0.5 versus -1.1; P < 0.01). Using multiple regression, running distance (-) and BMI (+) together best predicted lumbar spine T scores (r(2) = 0.402; P < 0.01) in females. Although weak, BMI (+) best predicted hip T scores (r(2) = 0.167; P < 0.05). In males, running distance and training years (-) together best predicted lumbar spine T scores (r(2) = 0.400; P < 0.01). Training years (-) best predicted hip T scores (r(2) = 0.361; P < 0.01). To conclude, our findings suggest that male runners face the same bone threat at the spine, as female runners. Further research in male athletes is required. Incorporation of regular resistance training into an athlete's training programme may be a useful preventative strategy.

A comparison of bone mineral density in adolescent female swimmers, soccer players, and weight lifters

PURPOSE

The study was designed to examine the effect of sports of varying skeletal loading on bone density in adolescent female athletes.

METHODS

Bone mineral densities of female swimmers, soccer players, and weight lifters were examined. Between-sport comparisons were made using a one-way analysis of covariance with age and body mass index as covariates and group bone mass density (BMD) was compared to the World Health Organization's (WHO) normative values for adult females.

RESULTS

BMD was significantly greater in the soccer group compared to the weight lifting (p = 0.025) and swimming groups (p = 0.001) with no difference between weight-lifting and swimming groups (p = 0.209). Compared to normative data from the WHO, soccer was the only sport whose participants' BMDs were significantly greater than adult norms (p = 0.003), while those of the swimmers were significantly less (p < 0.001) than adult females, and the weight lifters were not different (p = 0.103).

CONCLUSIONS

Participation in sports such as soccer or weight lifting with significant skeletal loading may enhance BMD in adolescent females.