RESUMEN

UNLABELLED: The relationship between spinal curvature and bone mineral density (BMD) in women was examined. Significant relationships were observed between spinal curvature and BMD in both pre- and postmenopausal women. Excessive spinal curvature may be associated with low bone mass in premenopausal women. INTRODUCTION: The purpose of this study was to examine the associations between spinal measurements of thoracic and lumbar curvatures and bone mineral density in pre- and postmenopausal women. METHODS: The data for this study were obtained from the Texas Woman's University Pioneer Project. Female participants (n = 242; premenopausal n = 104, postmenopausal n = 138) between the ages of 18 and 60 years were evaluated on multiple health measures. Thoracic and lumbar curvatures were measured with a 24-in. (60 cm) flexicurve. Bone mineral density was assessed via dual-energy X-ray absorptiometry (Lunar DPX IQ, version 4.6e). Pearson correlations and logistic regression analysis were used to examine the associations between the obtained spinal curvature measurements and bone mineral density. Significance was set at p < .05. RESULTS: Significant correlations were observed for the femoral neck and lumbar spine bone mineral density with thoracic and lumbar curve in premenopausal women (r = -.344 to - .525; p < .001). Slightly weaker, but significant, correlations were observed for femoral neck and lumbar spine in relation to thoracic and lumbar curve in postmenopausal women (r = -.288 to -.397; p < .01). Premenopausal women with thoracic curvature greater than 4 cm had a greater risk of having low bone mass compared to premenopausal women with less than 4 cm of curvature (odds ratio = 3.982, 95 % CI = 1.206, 13.144). CONCLUSIONS: The observed negative relationship suggests that as either thoracic or lumbar curvature increases, the regional bone mineral density decreases in both pre- and postmenopausal women.

Asunto(s)

RESUMEN

Undesirable changes in health-related parameters are thought to occur in retiring female athletes, but this has not been examined in longitudinal studies. The purpose of this study was to examine longitudinal changes in bone mineral density (BMD), body composition, and dietary intake in gymnasts and controls. Nonathletic, college-age women (: n = 9) were selected as a control group for comparison to the gymnasts (n = 10). Initial BMDs for the gymnasts were determined by using dual energy X-ray absorptiometry (Lunar, DPX) at the beginning of their final competitive year. Initial BMDs for the controls were measured during a similar time-frame. Follow-up measurements were made at least 1-year after the initial measurement. Gymnasts had significantly greater BMD of the femoral neck (1.262 versus 1.058 g/cm2, respectively), Ward's triangle (1.230 versus 1.008 g/cm2), greater trochanter (1002 versus 0.822 g/cm2), and total body (1.232 versus 1.145 g/cm2) than controls while still competing (P < .05). Following retirement from competition, (mean years of retirement, 4 years), BMD of the gymnasts remained significantly greater than controls at total body, femoral neck, trochanter, and Ward's triangle (P < .05). Significant declines in femoral neck, Ward's triangle, and greater trochanter BMD were found in both gymnasts and controls (0.72% to 1.9% per year), but only gymnasts had a significant decline at the lumbar spine (0.87% per year). In conclusion, BMD changes in former gymnasts appear to be site-specific, and gymnasts continue to have greater proximal femur BMD than controls, despite their decreased exercise, which may help postpone or prevent osteoporosis later in life.

Asunto(s)

RESUMEN

OBJECTIVE: To examine the effects of 15 months of resistance training on bone mineral density (BMD) in female adolescents (aged 14 to 17 years). STUDY DESIGN: Participants were randomly assigned to either a training (n = 46) or control group (n = 21). BMD and body composition were measured by using dual-energy x-ray absorptiometry. Strength was assessed by means of one-repetition maximums for the leg press and bench press. The exercise group trained 30 to 45 minutes a day, 3 days per week, using 15 different resistance exercises. Control participants remained sedentary (<2 hours of exercise per week). RESULTS: Leg strength increased significantly (40%) in the exercise group, but there were no changes in the control group. Femoral neck BMD increased significantly in the training group (1.035 to 1.073 g/cm(2), P <.01) but not in the control group (1.034 to 1.048 g/cm(2)). No significant changes were seen in either group in lumbar spine BMD (1.113 to 1.142 g/cm(2) and 1.158 to 1.190 g/cm(2), respectively) or total body BMD (1.103 to 1.134 g/cm(2) and 1.111 to 1.129 g/cm(2), respectively). CONCLUSION: Resistance training is a potential method for increasing bone density in adolescents, although such a program would be best done as part of the school curriculum.

Asunto(s)

RESUMEN

Female athletes are under intense pressure to have a low percentage of body fat for performance, which may result in a vulnerable athlete resorting to disordered eating, developing amenorrhea, and suffering the consequences of osteoporosis. Prevention of disordered eating practices among female athletes requires a de-emphasis of a low percentage of body fat and a good nutrition education program. The female athlete triad is a serious syndrome that requires a multidisciplinary approach to diagnosis and treatment.

Asunto(s)

RESUMEN

Good bone health is important to everyone, regardless of age. Osteoporosis is a preventable disease, and steps for increasing bone mass should begin at an early age. To increase bone mass, much of the recent evidence suggests that the best time for intervention with calcium or exercise may be during the prepubertal years. In the older female athlete, BMD is typically well above normal, but even young amenorrheic athletes can have bone density values equal to that of an elderly osteoporotic woman. Myriad treatment options are available for the person with low bone mass, but prevention is a much more preferable alternative.

Asunto(s)

RESUMEN

BACKGROUND: The purpose of this study was to determine if there were significant differences in lumbar bone mineral density (L2-L4, g/cm2) or several hormones among 3 groups of adolescent females: 10 amenorrheic runners, 10 eumenorrheic runners, and 10 eumenorrheic controls. EXPERIMENTAL DESIGN: comparative. SETTING: Cooper Clinic, Aerobics Center, Dallas, Texas. PATIENTS OR PARTICIPANTS: The subjects were white, non-smokers, aged 15.1-18.8 years, who were not taking birth control pills. All amenorrheic runners had less than 5 menstrual period in the past year, averaging 2,4 periods. The runners averaged approximately 36 miles/week (58.1 km) during the last 9 months of their training season and had been running for 1-5 years. INTERVENTIONS: None. MEASURES: Lumbar bone mineral density (BMD), 10 hormones, percentage of body fat, and dietary intake were measured. RESULTS: Mean lumbar BMD (g/cm2) did not differ significantly among groups (amenorrheic runners = 1.134, eumenorrheic runners = 1.165, controls = 1.148). However, expected trends were observed. Compared to the controls, the amenorrheic runners tended to have lower lumbar BMD and the eumenorrheic runners, higher. Although there were significant differences in concentrations of five serum hormones measured, all mean hormonal values were within normal ranges. Calcium intakes were low for all groups. CONCLUSIONS: In this study, with its small number of subjects and great variability within each group, it was concluded that there is no significant difference among amenorrheic runners, eumenorrheic runners, and controls in lumbar BMD. However, a longer period of amenorrhea might result in significantly lower BMD for the amenorrheic runners.

Asunto(s)

RESUMEN

The purpose of this study was to determine if differences exist in premenopausal women between z-scores for lumbar spine and proximal femoral bone mineral densities (BMD). Participants were 237 women ranging in age from 20 to 45 years. BMDs of the lumbar spine and proximal femur (femoral neck, Ward's area, and trochanter) were assessed using dual-energy X-ray absorptiometry (Lunar DPX). Mean (+/-SD) age, height, and weight of the participants were 29.4 +/- 6.9 years, 164.4 +/- 6.1 cm, and 64.9 +/- 12.1 kg, respectively. Lumbar spine BMD and BMD at the femoral neck, Ward's area, and trochanter were significantly correlated with large SEEs (r = 0.59-0. 65; SEE = 0.09-0.11). No positive correlation with age and BMD at any site was seen in this population but a significant negative correlation with age was seen in the proximal femur beginning at age 30. Twenty to 24% of the 20-29-year-olds exhibited a difference in z-scores of greater than 1 between the spine and sites in the proximal femur. This percentage increased to 32-46% in the 30-45-year-olds but the nature of the observed differences changed. The differences in spine and proximal femoral z-scores that are seen in the older age group appear to be the result of the earlier onset of bone loss in the proximal femur rather than an initial difference in peak bone mass which has been maintained.

Asunto(s)

RESUMEN

The purpose of this study was to determine if differences existed between right and left proximal femur bone mineral density (BMD) in a group of women. Participants for the study were 198 women ranging in age from 16 to 73 years. Bone mineral densities of both proximal femurs (femoral neck, Ward's area, and trochanter) were assessed using dual energy X-ray absorptiometry (Lunar DPX). Mean (+/-SD) age, height, and weight of the participants were 32.9 +/- 18 years, 164 +/- 7.4 cm, and 64.9 +/- 12.1 kg, respectively. Significant differences between right and left femoral BMDs were found only in the trochanter. Overall, mean differences in BMD were low (neck = 0. 7%, Ward's = 0.2%, and trochanter = 1.9%) but individual variations were as high as 22%. Based on BMD z-scores of <-1.0, 84 women were classified as "at risk" for osteoporosis. When right and left z-scores were compared, misclassifications of at risk women were 4, 15, and 11 for neck, Ward's area, and trochanter, respectively. In conclusion, analyses of both right and left proximal femurs may not be necessary for either the researcher or the clinician.

Asunto(s)

RESUMEN

The associations of body fat distribution, sex hormone levels, and bone mineral density (BMD) were examined in 52 postmenopausal Caucasian women. Body fat distribution was assessed by waist to hip ratio (WHR) and abdominal fat weight (between the iliac crest and L1), as determined by dual energy x-ray absorptiometry. Bone mineral densities were determined by dual energy x-ray absorptiometry, and total estradiol, total testosterone, and sex hormone-binding globulin (SHBG) levels were determined by RIA. Subjects taking hormone replacement had significantly greater total estradiol and SHBG concentrations and a lower free androgen index. BMDs tended to be higher in subjects taking estrogen replacement after adjustment for body weight. There was no difference between subjects taking hormone replacement or not taking hormone replacement in WHR or abdominal fat weight. Subjects with a gynoid (lower body) distribution of body fat had higher SHBG concentrations than subjects with a more android (upper body) distribution of body fat. Subjects with an android distribution of body fat had greater BMDs than subjects with a gynoid distribution of body fat. Abdominal fat weight and WHR were significant predictors in regression models for all BMD parameters. The results of this study suggest that there is an association between body fat distribution and BMD, with the android distribution having higher BMDs.

Asunto(s)

RESUMEN

The purpose of this study was to examine relationships between regional body composition and bone mineral density (BMD) in college females. Subjects were 12 nonathletic females (< 3 h.wk-1 of exercise) and 46 female varsity athletes: basketball (N = 14), volleyball (N = 13), gymnastics (N = 13), and tennis (N = 6). Dual energy x-ray absorptiometry was used to determine BMD and body composition. The mean (+/- SD) age, height, weight, and menarche for the subjects were 19.9 +/- 2.1 yr, 167.9 +/- 9.4 cm, 62.1 +/- 9.0 kg, and 13.6 +/- 1.7 yr, respectively. Mean lumbar (1.327 g.cm-2), femoral neck (1.172 g.cm-2), and total body (1.200 g.cm-2) BMD of the athletes were significantly greater than nonathletes (P < 0.05) but did not differ among the teams. Significant correlations were found between regional leg BMD and leg lean tissue mass (LTM) (r = 0.59, P < 0.001) and between arm LTM and arm and lumbar BMD (r = 0.47 and 0.56, respectively). Significant correlations were also found between leg fat mass and leg BMD (r = 0.40). However, only regional LTM was a significant predictor of BMD using stepwise multiple regression. In summary, regional LTM appears to be a better predictor of BMD than regional fat mass.

Asunto(s)

RESUMEN

The purpose of this study was to examine the effect of 27 wk of gymnastics training on bone mineral density (BMD), body composition, insulin-like growth factor I (IGF-I), and osteocalcin. Subjects were 11 female intercollegiate gymnasts and 11 controls. Dual energy x-ray absorptiometry (Lunar DPX) was used to determine BMD (L2-L4 and femur) and to assess body composition. The gymnasts were significantly lower in weight (53.9 and 60.8 kg) and % body fat (22.6 and 30.6) compared with controls. After training, body weights of gymnasts remained the same but there was a significant increase in lean tissue mass of 2.9 kg (6.7%, P < 0.05). No changes in body composition were observed in the controls. The gymnasts had significantly higher mean lumbar (1.321 vs 1.225), and femoral neck (1.163 vs 1.079) BMD (g.cm-2) than the controls. Lumbar BMD increased significantly (1.3%) in gymnasts following training but femoral neck BMD did not increase. No BMD changes occurred in the control group. Regarding serum IGF-I, no differences were seen between the groups or across time. Serum osteocalcin values were significantly higher in the gymnasts than the controls, but no differences were found across time. In conclusion, gymnasts had significantly higher BMDs than controls, and a significant increase in lumbar BMD was seen in the gymnasts following 27 wk of training.

Asunto(s)

RESUMEN

Body size, body composition, and physiology are basically similar in boys and girls before puberty. The adolescent growth spurt and puberty mark the period in life when sex differentiation and development begin. Peak height velocity for girls ranges from 10.5 to 13 years and for boys, 12.5 to 15 years. Peak weight velocity and menarche occur approximately 6 months and 1 year, respectively, after the height peak. On average, women have a larger surface area-to-mass ratio; lower bone mass; and wider, shallower pelvis compared with men. The implication of these characteristics is that women may have an advantage in dry heat, are more at risk for osteoporosis, and may be predisposed to experiencing knee problems. Overall, adult women have more body fat, less lean muscle mass, a gynoidal fat distribution, a lower resting metabolic rate, lower red blood cell mass, and lower hemoglobin and hematocrit compared with adult men. The difference in muscle strength between trained women and men can be explained by muscle mass size and not to differences in muscle fiber type or muscle adaptation. The lower resting metabolic rate is not related to gender per se, but to the fact that muscle mass is more metabolically active compared with fat. The lower VO2max in female athletes is explained primarily by differences in body composition and oxygen transport system between the sexes. A major problem occurring among female athletes is the misuse of prescribing low body fat for appearance and performance. The outcome is an athlete who appears to be in a negative caloric balance, and who is deficient in key nutrients. The consequences could result in the following cascading problems: disordered eating, iron deficiency anemia, amenorrhea, premature osteoporosis, and injuries.

Asunto(s)

RESUMEN

We hypothesized that menstrual disturbances in female athletes arise from opioid-induced abnormalities in gonadotropin and/or prolactin (PRL) secretion. To investigate this hypothesis, we measured luteinizing hormone, follicle-stimulating hormone, and PRL levels in eumenorrheic and amenorrheic athletes during thyrotropin-releasing hormone and gonadotropin-releasing hormone tests at baseline, after naloxone infusions, after exercise to exhaustion, and after similar exercise during naloxone infusions. Contrary to our hypothesis, amenorrheic runners did not have significant alterations in basal, postexercise, or stimulated hormone levels compared with eumenorrheic runners. In addition, opioid blockade by naloxone did not enhance gonadotropin release by amenorrheic athletes.

Asunto(s)

RESUMEN

While studying amenorrheic runners, the authors became aware of psychiatric differences between them. Psychiatric interviews of 13 amenorrheic and 19 regularly menstruating runners revealed that of the amenorrheic runners, 11 reported major affective disorders in themselves or in first- and second-degree relatives and eight reported eating disorders in themselves. Among the regularly menstruating runners, however, there were no eating disorders or major affective disorders, and only one had first-degree relatives with major affective disorders. These data suggest a link between athletic amenorrhea in runners, major affective disorders, and eating disorders.

Asunto(s)

RESUMEN

The most commonly tested hypothetical cause of athletic amenorrhea has been low body fat. Test results have conflicted because of mixed groups of athletes and methodologic problems. In this study, we measured body fat only in distance runners (greater than 53 km X wk-1) of the same somatotype who clearly had regular menses or secondary amenorrhea; this permitted more valid group comparison of body fat using hydrostatic weighing. The regularly menstruating group (N = 7) had 12 periods X yr-1 at intervals of 26.5 +/- 1.0 (SE) days with a duration of 4.1 +/- 0.4 days. In the athletic amenorrhea group (N = 7), menstrual periods had been absent for 1 to 10 yr (average = 3.9 +/- 1.3 yr); they were gynecologically evaluated to restrict the group to those with athletic amenorrhea. The groups were similar in a number of categories: weight, height, age, menarcheal age, weekly training mileage, days/week training, years of training, and maximum oxygen uptake. Percent body fat for the two groups was the same: 17.7 +/- 2.1% for the amenorrheic athletes and 17.4 +/- 1.2% for the regularly menstruating athletes (P = 0.91). These data do not support the idea that low body fat per se causes athletic amenorrhea.

Asunto(s)

Asunto(s)

Asunto(s)