Bone mineral density in young female Chinese dancers

Osteoporosis among Postmenopausal Women in Jordan: A National Cross-Sectional Study

Osteoporosis is considered a widespread health problem that affects senior citizens, particularly older women, after the menopause. This national study aimed to estimate the prevalence of osteoporosis among Jordanian postmenopausal women and to determine the association of demographic and nutritional factors, such as calcium and vitamin D supplement intake, with osteoporosis in postmenopausal women. A cross-sectional study was conducted among 884 postmenopausal women aged ≥50 years. A multistage sampling technique was used to select participants from three geographic regions of Jordan (north, middle, and south). The data were collected from the participants by a team of field researchers comprising men and women through a standard questionnaire. The prevalence of osteoporosis was 19.8% among postmenopausal Jordanian women. The study results showed that age (p ˂ 0.001), geographic region (p = 0.019), occupation (p = 0.002), and educational level (p = 0.001) were significantly associated with osteoporosis. Moreover, osteoporosis was significantly associated with calcium and vitamin D supplement intake (p < 0.05). There is a high prevalence of osteoporosis among postmenopausal Jordanian women. Therefore, there is a need to educate women at this age, and probably at an earlier age, to prevent or reduce the development of osteoporosis.

Bone mineral density in adolescent elite ballet dancers

BACKGROUND

Data documenting BMD in pre-professional adolescent ballet dancers is limited. This cross-sectional study assesses bone mineral density (BMD) in young adolescent elite ballet dancers and compares BMD values between males and females (with and without normal menarche) and body composition between dancers with and without low Z-score.

METHODS

Cross-sectional study of third year ballet students (female=23; male=15; mean age 14.7 years; SD: 0.5) of The Royal Ballet School of Antwerp (Belgium) training 22 hours a week. They completed questionnaires and underwent dual energy X-ray absorptiometry (DXA) to measure BMD and body composition. Each female participant completed questionnaires assessing menstrual status.

RESULTS

DXA revealed that 12 out of 38 (32%) of the dancers had Z-score <-1. On average, male dancers had a lower BMD compared to an age-matched reference population (mean Z-score -0.9; SD 0.5), with 7 out of 15 having Z-score <-1. Overall, absolute BMD values were highest in the legs, followed by spine and arms. Dancers with Z-score <-1 had a significantly lower total mass. 43% of female ballet dancers had not yet had their first period and 39% had oligomenorrhea, but no significant differences between groups was detected.

CONCLUSIONS

A third of adolescent elite ballet dancers had low to very low Z-score. Nearly 2 out of 3 dancers with a Z-score <-1 were males, showing that low BMD is not limited to female dancers. Among female dancers menstrual dysfunction was frequent, without apparent impact on BMD or body composition in the studied age group.

Bone mineral density in pre-professional female ballet dancers: A systematic review and meta-analysis

OBJECTIVES

To quantitatively compare bone mineral density (BMD) outcomes between pre-professional female adolescent ballet dancers and control populations.

DESIGN

Systematic review and meta-analysis.

METHODS

Six electronic databases and relevant journals were systematically searched up to August 2017. Included articles examined BMD in adolescent females undergoing pre-professional ballet training and healthy age-matched controls with an available English full text. Dancers were aged 15-19 years and trained in ballet at least 10h per week. BMD data were analysed via standardized mean difference to account for differences in reporting methods RESULTS: From 3984 potential articles, 8 cross-sectional studies were accepted for inclusion, which compared 293 dancers (16.9±0.8 years) to 333 controls (16.9±0.9 years). No data were available from longitudinal studies. Dancers displayed lower BMD at the radius and higher BMD at the femoral neck, femoral trochanter and Ward's triangle. No significant differences were observed in the lumbar spine or tibia. The overall study quality was low and heterogeneity was present in some analyses.

CONCLUSIONS

This meta-analysis indicates that there may be a site-specific osteogenic effect of pre-professional classical ballet training in adolescent females, with a notable and concerning finding of reduced upper limb BMD compared to age-matched controls. Longitudinal cohort studies are required to confirm the effects of pre-professional ballet training on BMD during adolescence.

Prevalence of low bone mineral density in female dancers

BACKGROUND AND OBJECTIVE

While some authors report that dancers have reduced bone mineral density (BMD) and increased risk of osteoporosis, others have stressed the positive effects of dance training on developing healthy BMD. Given the existing controversy, the aim of this systematic review was to examine the best evidence-based information available in relation to female dancers.

METHODS

Four databases (Web of Science, PubMed, EBSCO, Scopus) and two dance science journals (Journal of Dance Medicine and Science and Medical Problems of Performing Artists) were searched for relevant material using the keywords "dance", "ballet", "BMD", "bone density", "osteoporosis" and "female athlete triad syndrome". A total of 257 abstracts were screened using selected inclusion (studies involving bone measurements in dancers) and exclusion (editorials, opinion papers, chapters in books, narrative reviews and non-English language papers) criteria according to PRISMA guidelines. Following the above screening, a total of 108 abstracts were identified as potentially relevant. After the exclusion of conference proceedings, review papers, studies focusing only in male dancers and studies in which dancers' information were combined with other athletes, the eligible papers were subsequently assessed using the GRADE system and grouped according to: (1) prevalence of low BMD and associated factors, (2) incidence of low BMD and risk factors, (3) prevention/treatment of low BMD in dancers, and (4) other studies.

RESULTS

Of the 257 abstracts that were initially screened, only 35 studies were finally considered. Only one of these 35 was of high quality, while the remaining 34 were of relatively low quality. Seven studies reported prevalence of low BMD and associated factors, 10 reported associated factors with no prevalence data, while one reported prevalence with no associated factors data. One study cited risk factors, while another one elaborated on the treatment of low BMD in dancers. The remaining 15 studies were classified as "other studies".

CONCLUSIONS

It remains unclear whether low BMD is prevalent in female dancers. The present review highlights the need for high-quality BMD research in this area.

Effects of electroacupuncture at GB points on markers of osteoporosis and bodyweight in ovariectomised rats

Background

Based on a description of acupuncture to treat a bone disease resembling osteoporosis in the ancient text of Huangdi Neijing, we aimed to assess the effects of electroacupuncture (EA) at GB points in ovariectomised (OVX) rats.

Methods

40 female Wistar rats were randomly divided into four groups (n=10 each): ovariectomised model group (OVX); ovariectomised group treated with EA at GB points (OVX+GB); ovariectomised group treated with EA at non-GB points (OVX+N) in the hindlimb; and a sham surgery group (Sham). Three months after ovariectomy, rats in the OVX+GB and OVX+N groups received EA treatment for 3 months. Urine, blood and femur samples were collected from each animal for analysis.

Results

Bodyweight (BW) in the OVX+GB group decreased after EA treatment, reaching a minimum of ∼12% below the OVX and OVX+N groups at 1 month. Concentrations of urine deoxypyridinoline, a bone resorption marker, were significantly elevated in the OVX and OVX+N groups but not the OVX+GB group. Concentrations of serum bone specific alkaline phosphatase, a bone formation marker, were significantly higher in the OVX+GB group versus the Sham and OVX groups. Bone mineral density (BMD) did not differ between the OVX, OVX+GB and OVX+N groups, but was ∼10% lower than the Sham group. However, BMD/BW in the OVX+GB group was significantly higher than in the OVX and OVX+N groups and similar to the Sham group. Histological assessment of the femur showed that EA at GB points improved the bone architecture.

Conclusions

EA treatment at GB points had anti-osteoporotic effects in a rat model of osteoporosis.

Relatively high bone mineral density in Chinese adolescent dancers despite lower energy intake and menstrual disorder

OBJECTIVE

The effect of dietary restriction, intense exercise and menstrual dysfunction on bone mineral density remains controversial. The aim of this study was to assess the skeletal health status and relationship between bone mineral density and nutrient intake, menstrual status, estrogen level and other factos in Chinese adolescent dancers.

METHODS

Sixty dancers and 77 healthy controls underwent measurements of bone density, body composition, and estrogen level. Nutrient intake, menstrual status and physical activity were assessed with questionnaires. The correlation between these factors were analyzed.

RESULTS

The dancers under study had a significantly lean body mass index (18.3 +/- 1.4 kg/m2 vs. 21.7 +/- 3.1 kg/m2), lower percentage of body fat (0.25 +/- 0.05 vs. 0.34 +/- 0.04) and later age at menarche (14.0 +/- 0.9 y vs. 13.0 +/- 1.3 y), and the estrogen level, daily calorie and fat intake in them were also lower than in the controls. All the dancers undertook intensive physical activity every day and up to 69% of them suffered from irregular menarche. Yet they had relatively high BMD and BMC of the total body and legs than the controls after adjusting for BMI and age. Site-specific BMD was positively correlated to BMI, body composition and training hours per week and negatively correlated to the age at menarche and menstrual frequency.

CONCLUSIONS

The relatively high BMD and BMC of the dancers at the total body and legs were probably caused by high levels of weight-bearing physical activity. To ameliorate disordered eating, especially low energy intake might be helpful to prevent the Triad and to improve the bone health in adolescent dancers.

Risk factors for postmenopausal osteoporosis: anthropometric measurements, age, age at menopause and the time elapsed after menopause onset

OBJECTIVES

The aim of this study was to determine, how much the anthropometric measurements and age affect the femur and vertebra T-scores by using correlation and regression analysis in postmenopausal women.

METHODS

Data of 540 healthy postmenopausal women were included in this analysis. Bone mineral density was determined by dual energy X-ray absorptiometry (DXA). The data of the patients related to height, weight, age, age at menopause were obtained from records, and body mass index (BMI) was calculated (BMI = W (kg)/H(m(2))). Statistical analyses were performed with SPSS 15.0 for Windows (SPSS, Chicago, IL).

RESULTS

Mean age and standard deviation of 540 postmenopausal women was 59.3 +/- 8.4 years. The correlation coefficients among femur, vertebra T-scores, weight, the time elapsed after the menopause onset, age, BMI and height were found as follows, from higher to lower values with 0.465, 0.453, 0.411, 0.382, 0.232, respectively, and were statistically significant (p < 0.001).

CONCLUSIONS

We determined the effects of the anthropometric measurements on osteoporosis from higher to lower influence as follows: weight, menopause age, age, BMI and height. Weight and menopause age of the patients were the major determinants for osteoporosis.

Bone mineral density differences between adolescent dancers and non-exercising adolescent females

STUDY OBJECTIVE

To compare the bone mineral density (BMD) of the axial and appendicular skeleton between regularly exercising collegiate dancers and age matched non-exercising young females between the age of 17 and 19 to assess the impact of weight-bearing exercises and menstrual status on BMD.

DESIGN

Prospective observational cohort.

SETTING

Sports clinic in a collegiate school of dance and a hospital-based adolescent clinic.

PARTICIPANTS

The adolescent dancers consisted of full-time collegiate dance students from a tertiary Performing Arts Institute (n = 35). The non-exercising controls consisted of eumenorrhoeic patients of the same age presenting to the Adolescent Clinic (n = 35).

INTERVENTIONS

All subjects had a full hormonal profile, bio-impedance estimation of body fat, and dual energy X-ray absorptiometry and quantitative peripheral CT scans (pQCT) to determine bone density.

MAIN OUTCOME MEASURES

Comparison of the mean bone mineral density in the axial and appendicular skeleton between the two groups.

RESULTS

The incidence of oligo/amenorrhoea in the dancers was 20%. The lumbar spine BMD (1.006 g/cm(2) vs. 0.938, P = 0.048) and hip BMD (neck of femur 0.978 g/cm(2) vs. 0.838, P < 0.001; Ward's triangle 0.816 g/cm(2) vs. 0.720, P = 0.003; trochanter 0.777 g/cm(2) vs. 0.682; P < 0.001) were significantly higher in the eumenorrhoeic dancers as compared to controls. The radial BMD as measured by pQCT did not differ between the two groups, but the core trabecular tibial BMD was also higher in the dancers (321 mg/cm(3) vs. 286, P = 0.006). When only oligo/amenorrhoeic dancers (n = 7) were compared with the controls, the same differences in BMD values were no longer observed.

CONCLUSION

Young women undergoing regular intensive weight-bearing exercises as in the collegiate dancers here studied have higher BMD in the axial and appendicular skeleton as compared to non-exercising females of the same age if they remain eumenorrhoeic during their training. This advantage was apparently lost when they developed oligo/amenorrhoea.

Prevalence of osteoporosis and its reproductive risk factors among Jordanian women: a cross-sectional study

Extensive differences in the osteoporosis epidemiological pattern among geographic and ethnic groups have been reported. The evidence concerning association of multiple pregnancies, lactations, and other menstrual history factors with low bone mineral density (BMD) remains inconclusive. Previous local studies addressing these issues in Jordan are very restricted. We present a cross-sectional study of Jordanian women who visited outpatient clinics between August 2000 and August 2002 at two community hospitals in Amman City. BMD measurement was performed for all subjects, while comprehensive appraisal of clinical issues related to reproductive status and past medical history was carried out using a structured questionnaire administered to 50% of the subjects. We also attempted to examine the current hypothesis of possible influence of hyperlipidemia and thyroid abnormalities on decreased BMD. According to WHO criteria, 119 (29.6%) were identified as having osteoporosis, 176 (43.8%) were osteopenic, and 107 (26.6%) had normal BMD. The multiple-linear regression analyses at different bone sites revealed that age, years of menopause, low-density lipoprotein (LDL), and follicle-stimulating hormone (FSH) have strong independent associations with decreased BMD at all lumbar and femoral neck regions. The negative effect associated with number of children (live births) and frequency of lactations was only evident at femoral neck. Although years of menstruation, age at menopause, days of menstrual cycle, number of pregnancies, and duration of hormone replacement therapy (HRT) were positively correlated with BMD, they had weaker associations than previous variables. Moreover, in the final multivariable logistic regression model, variables which rendered significantly independent risk factors after adjustment for age and BMI were: current smokers of more that 25 cigarettes/day, postmenopausal women irrespective of HRT use, menopausal years of > or =5 year intervals, natural early menopause, gastrointestinal disease, rheumatoid arthritis, osteoarthritis, hypertension, and thyroid replacement therapy. Ever-lactation, frequent lactation of 4 or more times, duration of lactation interval of 1-6 months and clinical hyperthyroidism were significant protective factors. Hysterectomy with or without oophorectomy, premature ovarian failure, gravidity, menstrual flow pattern, family history of osteoporosis, clinical hypothyroidism, hyperlipidemia, HRT, and corticosteroids therapy were not independent predictors of osteoporosis among our population. It was concluded that the prevalence of this worldwide public health problem among the Jordanian female population is extremely high, and is even found in younger age categories compared to previous international surveys. Though, the number of pregnancies in our multiparous female population showed a negative impact on femoral neck BMD, no evidence of increased risk of osteoporosis among ever-pregnant women was noted. Conversely, the current data analysis highlight many potential risk factors including associated medical illnesses, and other hormonal alterations experienced during menopausal period. Therefore, increased health awareness and intensive screening programs are mandatory for early detection of low bone mass.