Growth and pubertal development in elite female rhythmic gymnasts

Optimal growth depends upon both environmental and genetic factors. Among environmental factors that could alter growth and sexual maturation are stress and intensive physical training. The influence of these factors has been documented in a variety of sports, but there is limited information on rhythmic gymnasts, who have entirely different training and performance requirements. The study was conducted during the 13th European Championships in Patras, Greece, and included 255 female rhythmic gymnasts, aged 11-23 yr. The study included measurement of height and weight, assessment of breast and pubic hair development, estimation of body fat and skeletal maturation, and registration of menarcheal age and parental height. Gymnasts were taller than average height for age, with mean height above and mean weight below the 50th percentile. Actual height SD score was positively correlated to weight SD score (P < 0.001), number of competitions (P = 0.01), and body mass index (BMI; P < 0.001). Predicted adult height SD score was positively correlated to weight SD score (P < 0.001) and negatively to body fat (P = 0.004). There was a delay in skeletal maturation of 1.3 yr (P < 0.001). Pubertal development was following bone age rather than chronological age. The mean age of menarche was significantly delayed from that of their mothers and sisters (P = 0.008 and P = 0.05, respectively), was positively correlated to the intensity of training and to the difference between chronological age and bone age (P < 0.001 and P = 0.002, respectively), and was negatively correlated to body fat (P < 0.001). In the elite female rhythmic gymnasts, psychological and somatic efforts have profound effects on growth and sexual development. Despite these aberrations, adult height is not expected to be affected.     

Leptin and bone mineral density: a cross-sectional study in obese and nonobese men

Leptin has been suggested to decrease bone mineral density (BMD). This observational analysis explored the relationship between serum leptin and BMD in 327 nonobese men (controls) (body mass index 26.1 +/- 3.7 kg/m(2), age 49.9 +/- 6.0 yr) and 285 juvenile obese men (body mass index 35.9 +/- 5.9 kg/m(2), age 47.5 +/- 5.1 yr). Whole-body dual-energy x-ray absorptiometry scan measured BMD, fat mass, and lean mass. Fasting serum leptin (nanograms per milliliter) was strongly associated with fat mass (kilograms) in both controls (r = 0.876; P < 0.01) and juvenile obese (r = 0.838; P < 0.001). An inverse relation between BMD adjusted for body weight and serum leptin emerged in both the control group (r = -0.186; P < 0.01) and the juvenile obese group (r = -0.135; P < 0.05). In a multiple linear regression, fat mass, lean body mass, and occupational physical activity were positively associated with BMD in the control group, whereas in the juvenile obese, only lean body mass was positively associated with BMD and smoking negatively associated with BMD. Our study supports that leptin is inversely associated with BMD and may play a direct role in the bone metabolism in nonobese and obese Danish males, but it also stresses the fact that the strong covariation between the examined variables is a shortcoming of the cross-sectional design.     

Delayed but normally progressed puberty is more pronounced in artistic compared with rhythmic elite gymnasts due to the intensity of training

CONTEXT: Elite gymnasts are subjected to intense training, which may alter pubertal development. OBJECTIVE: The objective of the investigation was to study the impact of gymnastics on pubertal development in rhythmic (RGs) and artistic gymnasts (AGs). DESIGN: Evaluation of somatometric parameters, pubertal stage, and intensity of training in the competition field were studied. SETTING: The study was conducted at European and world championships of years 1997-2004. SUBJECTS: Subjects included 433 elite RGs and 427 AGs, aged 11-23 yr. Intervention: There were no interventions. MAIN OUTCOME MEASURES: Mean chronological and bone ages of each pubertal stage and their relation to the intensity of training were measured. RESULTS: AGs and RGs showed a delay in skeletal maturation (Delta age-bone age, 2.13 and 1.28, respectively; P < 0.001). AGs were subjected to higher levels of physical training. Thelarche occurred at 12.9 yr for RGs and 13.2 yr for AGs (P = 0.003) and pubarche at 12.5 and 12.9 yr, respectively (P = 0.002). Puberty was delayed but normally progressed. AGs entered each pubertal stage later than RGs. The delay was influenced by the amount of energy output. Menarcheal age was 14.6 yr for RGs and 14.9 yr for AGs. Menarche was influenced in AGs by bone age (b = 0.333; t = 2.521; P = 0.020), pubarche (b = 0.322; t = 2.401; P = 0.026), and body fat (b = -0.458; t = -3.412; P = 0.003) and in RGs by bone age (b = 0.378; t = 3.689; P < 0.001) and pubarche (b = 0.525; t = 6.017; P < 0.001). CONCLUSION: In RGs and AGs, pubertal development was shifted to a later age, maintaining a normal rate of progression, which followed the bone age. AGs, who were exposed to a greater and more sustained energy output than RGs, presented a more pronounced delay in both skeletal maturation and pubertal development.     

Bone mineral acquisition in healthy Asian, Hispanic, black, and Caucasian youth: a longitudinal study

Ethnic and gender differences in bone mineral acquisition were examined in a longitudinal study of 423 healthy Asian, black, Hispanic, and white males and females (aged 9-25 yr). Bone mass of the spine, femoral neck, total hip, and whole body was measured annually for up to 4 yr by dual energy x-ray absorptiometry. Age-adjusted mean bone mineral curves for areal (BMD) and volumetric (BMAD) bone mineral density were compared for the 4 ethnic groups. Consistent differences in areal and volumetric bone density were observed only between black and nonblack subjects. Among females, blacks had greater mean levels of BMD and BMAD at all skeletal sites. Differences among Asians, Hispanics, and white females were significant for femoral neck BMD, whole body BMD, and whole body bone mineral content/height ratio, for which Asians had significantly lower values; femoral neck BMAD in Asian and white females was lower than that in Hispanics. Like the females, black males had consistently greater mean values than nonblacks for all BMD and BMAD measurements. A few differences were also observed among nonblack male subjects. Whites had greater mean total hip BMD, whole body BMD, and whole body bone mineral content/height ratio than Asian and Hispanic males; Hispanics had lower spine BMD than white and Asian males. The tempo of gains in BMD varied by gender and skeletal site. In females, total hip, spine, and whole body BMD reached a plateau at 14.1, 15.7, and 16.4 yr, respectively. For males, gains in BMD leveled off at 15.7 yr for total hip and at age 17.6 yr for spine and whole body. Black and Asian females and Asian males tended to reach a plateau in BMD earlier than the other ethnic groups. The use of gender- and ethnic-specific standards is recommended when interpreting pediatric bone densitometry data.     

A 1-year prospective study on the relationship between physical activity, markers of bone metabolism, and bone acquisition in peripubertal girls

We conducted a 1-yr prospective study to evaluate the association between physical activity and biochemical markers of bone formation and resorption with bone mineral acquisition in 155 peripubertal Caucasian girls (51 gymnasts, 50 runners, and 54 nonathletic controls). The bone mineral density (BMD) of the femoral neck, the greater trochanter, and the lumbar spine were measured by dual energy x-ray absorptiometry. Serum biochemical markers of bone formation (osteocalcin, bone-specific alkaline phosphatase, amino-terminal propeptide of type I procollagen) and bone resorption (degradation product of C-terminal telopeptide of type I collagen) were measured. The 1-yr increase in BMD (adjusted for age, height, Tanner stage, BMD at baseline, and increases in height and weight) of the femoral neck was 0.037 g/cm2 x yr [95% confidence interval (CI), 0.019-0.051 g/cm2 x yr), and that of the greater trochanter was 0.020 g/cm2 x yr (95% CI, 0.003-0.039 g/cm2 x yr) greater in gymnasts than in controls. The corresponding figures for gymnasts compared with runners were 0.038 g/cm2 x yr (95% CI, 0.009-0.041 g/cm2 x yr) and 0.033 g/cm2 x yr (95% CI, 0.006 to 0.043 g/cm2 x yr). The figures for the lumbar spine did not differ significantly between study groups. The baseline serum concentrations of formation markers and resorption marker accounted for 2.3-12.8% (P < 0.05) of the variation in the 1-yr increase in BMD at the femoral neck and lumbar spine. However, there was no significant difference between the levels of adjusted baseline bone turnover markers of the gymnasts, runners, and controls. The present data add considerable support to the argument that high impact mechanical loading is extremely important and beneficial for the acquisition of BMD of the hip during peripubertal years. Our results indicate also that a high rate of bone turnover, reflected as elevated bone markers, is only weakly associated with the 1-yr bone gain in peripubertal girls.     

The effects of growth hormone treatment on bone mineral density and body composition in girls with turner syndrome

BACKGROUND: Many girls with Turner syndrome (TS) are treated with GH to increase adult height. In addition to promoting longitudinal bone growth, GH has effects on bone and body composition. OBJECTIVE: The objective was to determine how GH treatment affects bone mineral density (BMD) and body composition in girls with TS. METHOD: In a cross-sectional study, we compared measures of body composition and BMD by dual energy x-ray absorptiometry, and phalangeal cortical thickness by hand radiography in 28 girls with TS who had never received GH and 39 girls who were treated with GH for at least 1 yr. All girls were participants in a National Institutes of Health (NIH) Clinical Research Center (CRC) protocol between 2001 and 2006. RESULTS: The two groups were similar in age (12.3 yr, sd 2.9), bone age (11.5 yr, sd 2.6), and weight (42.8 kg, sd 16.6); but the GH-treated group was taller (134 vs. 137 cm, P = 0.001). The average duration of GH treatment was 4.2 (sd 3.2) yr (range 1-14 yr). After adjustment for size and bone age, there were no significant differences in BMD at L1-L4, 1/3 radius or cortical bone thickness measured at the second metacarpal. However, lean body mass percent was higher (P < 0.001), whereas body fat percent was lower (P < 0.001) in the GH-treated group. These effects were independent of estrogen exposure and were still apparent in girls that had finished GH treatment at least 1 yr previously. CONCLUSIONS: Although GH treatment has little effect on cortical or trabecular BMD in girls with TS, it is associated with increased lean body mass and reduced adiposity.     

Human growth hormone replacement in adult hypopituitary patients: long-term effects on body composition and lipid status--3-year results from the HypoCCS Database

The Hypopituitary Control and Complications Study is an international surveillance study evaluating efficacy and safety of GH therapy of adult GH-deficient patients in clinical practice. The present report examined baseline data from 1,123 adult onset (AO) and 362 childhood onset (CO) patients, as well as efficacy in 242 patients who had completed 3 yr of GH treatment. At study entry, mean height, body mass index, waist to hip ratio, and lean body mass were significantly (P < 0.001 for each) lower in CO compared with AO patients. After 3 yr on GH, lean body mass was significantly increased in AO males and females and CO males but not CO females, whereas fat mass was significantly decreased in AO males only. Serum total cholesterol was decreased in females (-0.32 +/- 1.00 mmol/liter; P = 0.045) and males (-0.36 +/- 0.96 mmol/liter; P = 0.004). High-density lipoprotein (HDL) cholesterol was increased for females (0.10 +/- 0.26 mmol/liter; P = 0.026) and males (0.10 +/- 0.34 mmol/liter; P = 0.022). The low-density lipoprotein/HDL ratio was decreased in AO males (-0.93 +/- 2.00; P = 0.003), AO females (-0.65 +/- 0.74; P < 0.001), and CO females (-0.69 +/- 0.76; P = 0.038), but the decrease in CO males was not significant (-0.84 +/- 2.85; P = 0.273). In AO patients, lean body mass increase from baseline was greatest in the those younger than 40 yr old, less but still significant in the middle group (40-60 yr) and unchanged in older (>60 yr) patients; conversely, decreases in the low-density lipoprotein/HDL ratio were small and not significant in the younger patients but greater and significant in the middle and older age groups. During the 3-yr treatment, 114 (7.7%) patients discontinued, including 9 (0.6%) for tumor recurrences, 9 (0.6%) for neoplasia, and 9 (0.6%) for side effects. Therefore, these observational data showed significant long-term efficacy of adult GH replacement therapy on body composition and lipid profiles and indicate that age is an important predictor of response.     

Measurement of bone mineral content of the lumbar spine by dual energy x-ray absorptiometry in normal children: correlations with growth parameters

The bone mineral density (BMD) of the lumbar spine (L1-L4) was measured by dual energy x-ray absorptiometry (Hologic QDR 1000) in 135 healthy caucasian children, aged 1-15 yr, and values were correlated with age, height, weight, body surface, bone age, pubertal status, calcium intake, vitamin D supplementation, and serum bone gla protein. BMD increased with age in children of both sexes (r = 0.88; P less than 0.001) from 0.446 +/- 0.048 g/cm2 at 1 yr to 0.625 +/- 0.068 g/cm2 at 10 yr and 0.891 +/- 0.123 g/cm2 at 15 yr of age. The increase was steeper at the time of puberty, reaching values above 0.80 g/cm2 after puberty was achieved. There were no significant differences between boys and girls, except at the age of 12 yr when BMD was higher in girls than in boys (P = 0.007), probably because of the earlier onset of puberty in females. BMD was also highly correlated with height, weight, body surface, and bone age. BMD was not correlated with calcium intake when age was held constant, nor with vitamin D supplementation. Serum bone gla protein showed a steady increase during childhood, with peak values at 11-12 yr of age, and was weakly but significantly correlated with BMD (r = 0.27; P = 0.007). Because of low irradiation exposure, rapid scanning, and high precision, dual energy x-ray absorptiometry is a noninvasive method which is well adapted to the child. It should be helpful in the investigation and follow-up of children with diseases impairing bone metabolism.     

Changes in bone density and bone markers in rhythmic gymnasts and ballet dancers: implications for puberty and leptin levels

OBJECTIVE: Our aim was to compare physical activity and biochemical markers with bone mineral acquisition in rhythmic gymnasts and ballet dancers. METHODS: Weight, height, body mass index, nutritional intake, bone age and menstrual histories were analyzed in nine rhythmic gymnasts, twelve ballet dancers and fourteen controls. Bone mineral density (BMD) was assessed by X-ray absorptiometry at the lumbar spine, hip and radius. Bone alkaline phosphatase (bAP) and amino-terminal propeptide of procollagen I (PNIP) in serum and urinary alpha-isomer of the carboxy-terminal telopeptide of collagen I (alpha-CTX) were measured. RESULTS: Bone age was delayed 2 years and mean age at menarche was 15+/-0.9 years in rhythmic gymnasts and 13.7+/-1 years in ballet dancers, compared with 12.5+/-1 years in controls. Trocanteric and femoral neck BMD was significantly higher in rhythmic gymnasts compared with ballet dancers and controls. Right forearm (non-loaded zone) BMD was significantly decreased in rhythmic gymnasts and ballet dancers compared with controls. All subjects had normal bAP and PNIP levels, but the alpha-CTX/creatinine (Cr) ratio was increased in rhythmic gymnasts (P<0.001) with an inverse correlation between right forearm BMD and the alpha-CTX/Cr ratio (r=-0.74, P<0.001). Serum leptin levels were decreased in rhythmic gymnasts and ballet dancers. Rhythmic gymnasts had a positive correlation between right forearm BMD and leptin levels (r=0.85, P<0.001). CONCLUSIONS: Decreased bone mass in rhythmic gymnasts could be partially explained by an increase in bone resorption. Serum leptin levels could be implicated in the pubertal delay and be a good marker of bone mass in these subjects.     

Bone mass at final height in precocious puberty after gonadotropin-releasing hormone agonist with and without calcium supplementation

The aim of our longitudinal study was to evaluate bone mass in girls affected by central precocious puberty (CPP) that have reached final height, treated with GnRH agonist triptorelin (GnRHa), with or without calcium supplementation. We studied 48 Caucasian females affected by CPP (age at diagnosis, 7.19 +/- 0.96 yr), randomly assigned to two groups: group A (n = 21) treated with GnRHa and group B (n = 27) treated with GnRHa plus calcium gluconolactate and carbonate (1 g calcium/day in two doses) for at least 2 yr. Auxological parameters (standing height, weight, body mass index) and bone mineral density (BMD) at the lumbar spine [L2-L4, anteroposterior (AP)-BMD; lateral BMD; volumetric (v)BMD)] by dual-energy x-ray absorptiometry were evaluated at the beginning [chronological age (CA), 7.29 +/- 0.91 yr; bone age (BA), 8.80 +/- 1.24 yr] and end of treatment (CA, 11.27 +/- 0.97 yr; BA, 12.35 +/- 0.43 yr) and at final height (CA, 16.17 +/- 1.9 yr; BA, 16.93 +/- 0.98 yr, in each case >15 yr). Total bone mineral content, total BMD, and fat percentage were evaluated at the end of the study period using dual-energy x-ray absorptiometry. Final height was significantly higher than predicted height at diagnosis (159.9 +/- 6.3 cm vs. 152.9 +/- 9.6 cm; P < 0.05). Body mass index and fat percentage were not statistically different from control values. Densitometric values at final evaluation in groups A and B together were lower than in controls, but the differences were not statistically significant. The vBMD was significantly higher in group B than in group A at the end of treatment period (0.213 +/- 0.022 g/cm(3) vs. 0.192 +/- 0.021 g/cm(3); P < 0.01) and at final evaluation (0.246 +/- 0.023 g/cm(3) vs. 0.227 +/- 0.024 g/cm(3); P < 0.05). The percentage change (Delta%) between the start and end of treatment period in AP-BMD and vBMD was significantly higher in group B than in group A (Delta% AP-BMD: 20.36% +/- 1.10% vs. 16.16% +/- 1.90%, P < 0.01; Delta% vBMD: 19.08% +/- 3.52% vs. 9.26% +/- 5.15%; P < 0.01) and also between the start of treatment and final evaluation (Delta% AP-BMD: 61.23% +/- 1.61% vs. 56.97% +/- 1.45%, P < 0.01; Delta% vBMD: 36.69% +/- 5.01% vs. 28.01% +/- 5.76%, P < 0.01). In all our females with CPP treated with GnRHa, bone densitometric parameters were in the normal range for age and sex. However, bone mass achievement seemed to be better preserved in the group of patients supplemented with calcium.     

Growth and skeletal maturation in male and female artistic gymnasts

We studied 262 athletes who were 13-23 yr old. There were 93 male and 169 female artistic gymnasts (AG). This study is unique in character, because all variables were measured on the field of competition (24th European Championship). Male AG had a higher height SD score than female (P < 0.001), with a higher reported target height SD score (P < 0.001), a higher predicted final height (P = 0.007), a lower Delta height - target height (P < 0.001), a less delayed bone age (P < 0.001), a greater body mass index (BMI) (P < 0.001), a lower mean body fat (P<0.001), and an older age of onset of training (P < 0.001). In a subgroup of athletes who had reached final height, male AG had a higher weight SD score than female (t = 4.322, P < 0.001), with a higher reported target height SD score (t = 18.9, P<0.001), but a greater Delta final height-target height (t= 6.641, P < 0.001). Height SD score was positively correlated to reported target height SD score (P = 0.009 and P = 0.006, respectively) and to weight SD (P < 1 and P < 0.001, respectively) for both male and female AG, as well as to BMI for female AG (P<0.001), and negatively to Delta age - bone age (P < 0.001 and P = 0.003, respectively) and to predicted height SD score (P = 0.001 and P < 0.001, respectively). Using multiple regression analysis, height SD score was positively correlated to predicted height SD score for both male (P < 0.001) and female (P = 0.005) AG, as well as to weight SD score (P < 0.001) for female AG and negatively to BMI (P < 0.001) for female AG and to Delta age - bone age (P < 0.001) for male AG. In conclusion, a deterioration of growth in AG was observed. For both sexes, genetic predisposition to final height, although altered, was not disrupted.     

Early and rapid bone mineral density loss of the proximal femur in men

CONTEXT: The changes in bone mineral density (BMD; grams per square centimeter), a well-known predictor of future fracture risk, are not well investigated in young men. OBJECTIVE: The objective of the study was to investigate the changes in BMD in men between 17 and 26 yr of age. DESIGN: This was a longitudinal study. PARTICIPANTS: Participants included 107 healthy males with a mean age of 17 yr at baseline. BMD was also measured in 81 of their fathers at a mean age of 50 yr. MAIN OUTCOME MEASURES: BMD of the total body, proximal femur, and lumbar spine was measured at baseline and after mean periods of 27, 66, and 92 months in the young cohort. RESULTS: BMD of the total body and lumbar spine initially increased to reach a plateau during the study period. At the proximal femur, peak values were obtained at 19 yr of age, followed by significant losses of almost 0.02 g/cm(2) per year (P < 0.001). At this site, the fathers' BMD indicated a further loss of about 0.0085 g/cm(2) per year up to the age of 50 yr. The BMD development at all sites was positively associated with physical activity (P < 0.05). However, changes in physical activity, weight, and height did not explain the local BMD loss seen at the proximal femur. CONCLUSION: Early losses of BMD at the proximal femur were found in this male sample. The results indicate that 25% of peak BMD at this site may be lost by the age of 50 yr in men. We suggest that bone remodeling may be regulated differently at the proximal femur than at other sites.     

The relation between bone mineral density, insulin-like growth factor I, lipoprotein (a), body composition, and muscle strength in adolescent males.

Osteoporosis is the most common metabolic bone disease. A low peak bone mass is regarded a risk factor for osteoporosis. Heredity, physical activity, and nutrition are regarded important measures for the observed variance in peak bone mass. Lp(a) lipoprotein is a well-known risk factor for atherosclerosis. Serum insulin-like growth factor I (IGF-I) has been found to be increased in males with early cardiovascular disease. In this study, we evaluated the association between bone mass, body constitution, muscle strength, Lp(a), and IGF-I in 47 Caucasian male adolescents (mean age, 16.9 yr). Bone mineral density (BMD) and body composition were measured by dual x-ray absorptiometry, muscle strength of thigh using an isokinetic dynamometer, IGF-I by RIA, and Lp(a) by enzyme-linked immunosorbent assay. IGF-I was only associated with Lp(a) (r = 0.38, P < 0.01). Lp(a) was related to total body (r = 0.40, P < 0.01), skull (r = 0.45, P < 0.01), and femoral neck BMD (r = 0.44, P < 0.01). Lp(a) was also related to fat mass (r = 0.34, P < 0.05) and muscle strength (r = 0.30-0.42, P < 0.05). After multiple regression and principal component (PC) analysis, the so-called PC body size (weight, fat mass, lean body mass, and muscle strength) was the most significant predictor of BMD (beta = 0.28-0.51, P < 0.05-0.01), followed by the so-called PC physical activity (beta = 0.28-0.38, P < 0.05-0.01, weight-bearing locations). However, the PC analysis confirmed that Lp(a) was an independent predictor of total body, skull, and femoral neck BMD (beta = 0.33-0.36, P < 0.01). The present investigation confirms that BMD, body size, and muscle strength are closely related and that the level of physical activity is a major determinant of BMD. However, the positive relation of Lp(a), a major risk factor for cardiovascular disease, to BMD has not previously been described. The importance of this observation has to be further investigated.     

Estradiol levels predict bone mineral density in male collegiate athletes: a pilot study

Objective Strenuous training commonly results in amenorrhoea, which contributes to bone loss in some female collegiate athletes. However, the impact of athletic training on endocrine function and bone mineral density (BMD) in male collegiate athletes is less well understood. The objective of the study was to investigate the specific endocrine determinants of BMD in male collegiate runners and wrestlers, including the potential impact of gonadal steroid levels. Design Cross‐sectional study. Patients Twenty‐six division I collegiate male athletes (wrestlers, runners and golfers). Measurements Main outcome measures included (i) BMD endpoints measured by dual energy x‐ray absorptiometry (DXA); (ii) endocrine end‐points: total and free oestradiol, total and free testosterone; (iii) body composition end‐points: lean and fat mass, measured by DXA; and (iv) exercise end‐points: maximal oxygen uptake (VO₂ max), number of miles run weekly and grip strength. Results Free and total oestradiol levels were important positive determinants of BMD. In contrast, total and free testosterone levels were not significant predictors of BMD at any skeletal site (except for free testosterone at the radius). In addition, lean body mass, % ideal body weight, total body weight, body mass index (BMI) and hours per week of resistance training were positive predictors of BMD. VO₂ max was a negative predictor of BMD. Mean BMD was higher at all skeletal sites in the wrestlers compared with the runners and a comparison group (golfers). Conclusions Our data suggest that oestradiol levels, BMI, and resistance training are more important determinants of BMD in male collegiate athletes than testosterone.     

Critical years and stages of puberty for spinal and femoral bone mass accumulation during adolescence

Maximizing peak bone mass is advocated as a way to prevent osteoporosis. As a prerequisite to the elaboration of any preventive program aimed at maximizing peak bone mass, it is important to determine how the rate of skeletal growth at clinically relevant sites, such as lumbar spine and femoral neck, proceeds in relation to age and pubertal stages in both sexes. Bone mass was assessed in 207 healthy caucasian boys and girls, aged 9-18 yr. Bone mineral density (BMD; grams per cm2) and content (BMC; grams) were determined in lumbar spine (L2-L4), femoral neck (FN), and midfemoral shaft (FS), using dual energy x-ray absorptiometry. Bone variables were correlated with both chronological age and pubertal stage, and compared with young adult (20-35 yr) reference values. The main results are: 1) in males, compared to females, there was a marked age-related delay in L2-L4 BMD or BMC increase, but no delay was observed in relation to pubertal stages; 2) at the end of the rapid growth spurt, trends for higher mean values in males were observed for L2-L4 BMC, FN BMD, and particularly FS BMD, but no sex difference was observed for L2-L4 BMD; 3) in females, but not in males, a dramatic reduction in bone mass growth was observed after 15 yr of age, particularly for L2-L4 BMD/BMC and FN BMD. This sharp reduction occurred between the second and fourth years after menarche. In the 14- to 15-yr-old female group, BMD in L2-L4, FN, and FS corresponded to 99.2%, 105.1%, and 94.1%, respectively, and BMC in L2-L4 to 97.6% of the mean values recorded in 20- to 35-yr-old women. In conclusion, this cross-sectional study indicates that during pubertal development, major differences are observed in bone mass growth according to sex and skeletal site. Whereas in males bone mass at different skeletal sites continues to increase substantially between 15-18 yr, skeletal mass growth appears to dramatically slow down at the levels of both lumbar spine and FN at 15-16 yr of age in female adolescents. This suggests that the generally accepted notion that in both males and females bone mass continues to substantially accumulate at all skeletal sites until the fourth decade may not be a constant in human physiology.     

Longitudinal follow-up of bone density and body composition in children with precocious or early puberty before, during and after cessation of GnRH agonist therapy

We studied bone mineral density (BMD), bone metabolism, and body composition in 47 children with central precocious puberty (n = 36) or early puberty (n = 11) before, during, and after cessation of GnRH agonist. Bone density and body composition were measured with dual energy x-ray absorptiometry and expressed as SD scores. Bone age and biochemical parameters of bone turnover were assessed. Measurements were performed at baseline, after 6 months, and on a yearly basis thereafter. Mean lumbar spine BMD SD scores for chronological age were significantly higher than zero at baseline and decreased during treatment. Lumbar spine bone mineral apparent density and total body BMD did not differ from normal at baseline and showed no significant changes during treatment. In contrast, BMD SD scores for bone age were significantly lower than zero at baseline and at cessation of therapy. Two years after therapy, bone mineral apparent density and BMD SD scores for bone age and chronological age did not differ from normal. Markers of bone turnover decreased during treatment, mainly in the first 6 months. Patients had increased percentage of fat and lean body mass at baseline. After an initial increase of percentage body fat during treatment, percentage body fat decreased and normalized within 1 yr after cessation of treatment. Our longitudinal analysis suggests that peak bone mass or body composition will not be impaired in patients with precocious or early puberty after GnRH agonist therapy.     

Voluntary weight reduction in older men increases hip bone loss: the osteoporotic fractures in men study

To test the hypothesis that weight loss in older men is associated with increased rates of hip bone loss regardless of adiposity and intention to lose weight, we measured body weight, body composition, hip bone mineral density (BMD), and intention to lose weight in a cohort of 1342 older men enrolled in the Osteoporotic Fractures in Men (MrOS) study and followed them prospectively for an average of 1.8 yr for changes in weight and BMD. The adjusted average rate of change in total hip BMD was 0.1%/yr in men with weight gain, -0.3%/yr in men with stable weight, and -1.4%/yr in men with weight loss (test for trend, P < 0.001). Higher rates of hip bone loss were observed in men with weight loss regardless of category of body mass index, body composition, or intention to lose weight. Even among obese (body mass index, > or =30 kg/m2) men trying to lose weight, those with documented voluntary weight reduction experienced an increase in hip bone loss (average rate of change in total hip BMD, 0.5%/yr in those with weight gain, -0.1%/yr in those with stable weight, and -1.7%/yr in those with weight loss; test for trend, P < 0.001). Older men who experience weight loss have increased rates of hip bone loss, even among overweight and obese men undergoing voluntary weight reduction.     

Relationship of body composition with prevalence of osteoporosis in central south Chinese postmenopausal women

Objectives To elucidate the relationship between body composition and bone mineral density (BMD) and the prevalence of osteoporosis in central south Chinese postmenopausal women. Methods A cross‐sectional study was conducted on 954 healthy central southern Chinese postmenopausal women, aged 50–82. Total body, lumbar spine and left femur BMD and total body soft tissue composition were measured by dual X‐ray absorptiometry. Results Among the study population, 578 (60·5%) subjects were without osteoporosis and 376 (39·4%) subjects were osteoporotic. The osteoporotic women were older, shorter and thinner, had an earlier age at menopause, a lower BMD and bone mineral content (BMC) of the total body and at different sites, and had lower body mass and body mass components than the women without osteoporosis. Both fat mass and lean mass were positively correlated with age at menopause, height, weight, body mass index (BMI) and BMD at all sites. Fat mass and lean mass were also inversely correlated with age and years since menopause (P < 0·05). After controlling for age, age at menopause and height, both fat mass and lean mass were positively correlated with BMD at the lumbar_1–4 spine, the femoral neck and the total hip. Fat mass was the most significant determinant of BMD at the lumbar_1–4 spine with a higher R² change and a partial R² compared with that of lean mass, while lean mass had more impact on the total hip values. Either a fat mass below 18·4 kg or a lean mass below 33·9 kg was correlated with a higher prevalence of osteoporosis at the lumbar spine or total hip. Conclusions In central south Chinese postmenopausal women, both fat mass and lean mass are correlated with BMD at the lumbar spine and hip. Fat mass was the most significant determinant of BMD at the lumbar spine, while lean mass had more impact on the total hip value. Both lower values of fat mass and lean mass are related to a higher prevalence of osteoporosis at either the lumbar spine or the total hip. Thus, it is important to maintain a reasonable body weight to balance bone health and other metabolic disorders.     

Longitudinal monitoring of bone mass accumulation in healthy adolescents: evidence for a marked reduction after 16 years of age at the levels of lumbar spine and femoral neck in female subjects.

The amount of skeletal mass acquired during adolescence is one of the most important determinants for the risk of postmenopausal and involutional osteoporosis. In both sexes, a large variance in bone mineral density (BMD) and content (BMC) is observed among healthy individuals at the beginning of the third decade. To determine the crucial pubertal years during which bone mass accumulation mainly occurs, we longitudinally monitored the gain in BMD/BMC at clinically important sites, such as lumbar spine and femoral neck, with respect to osteoporotic fracture risk. The changes in BMD (grams per cm2) and BMC (grams) were determined at 1-yr intervals at the level of lumbar spine vertebrae (L2-L4), femoral neck, and midfemoral shaft, using dual energy x-ray absorptiometry (Hologic QDR 1000), in 198 healthy adolescents (98 females and 100 males), aged 9-19 yr. Mean daily energy and calcium intakes, height, weight, and body mass index of the studied cohort were within the normal range for age. In females, the increment rate in BMD/BMC was particularly pronounced over a 3-yr period, i.e. from 11-14 yr of age. This increment dramatically fell after 16 yr and/or 2 yr after menarche. The mean gains in lumbar, femoral neck, and midfemoral shaft BMD were not statistically significant between 17-20 yr. In males, the gain in BMD/BMC was particularly high over a 4-yr period, i.e. from 13-17 yr. Then the increment rate markedly declined, but remained significant between 17-20 yr for L2-L4 BMD/BMC and midfemoral shaft BMD. In contrast, no significant increase was observed for femoral neck BMD. An impressive interindividual variation was observed between the yearly height increment and the bone mass accumulation. The bone mass-height gains relationship during puberty evolved according to a loop pattern, with maximal variance at Tanner stages P3-P4. This longitudinal study delineates the crucial pubertal years during which the skeletal mass accumulates at high, but various, rates at skeletal sites where the consequences of the osteoporosis are particularly dramatic. Furthermore, the results indicate that in a cohort of healthy females with apparently adequate intakes of energy and calcium, bone mass accumulation is drastically reduced by 16 yr of age in both lumbar spine and femoral neck.     

Bone mineral density in children and young adults with Crohn's disease.

Reduced bone mineral density (BMD) has been reported in adults with Crohn's disease (CD). Less is known about abnormal BMD in children and young adults with CD. The aims of this study are to determine the prevalence of low BMD and to evaluate the effect of growth and pubertal development on BMD in children and young adults with CD. One hundred-nineteen patients with CD underwent dual-energy X-ray absorptiometry (DXA) to determine BMD. Anthropometry and pubertal development were measured. Bone age was measured only in patients older than 8 years of age and who had not grown in height during the last year. One hundred-nineteen patients (72 male, 47 female) were evaluated. Seventy percent of patients had BMD z-scores < or = -1.0 and 32% had z-scores < or = -2.0. Weight and height z-scores were significantly associated with BMD z-scores. BMD z-scores based on bone age and on chronological age were highly correlated, except when the chronological age BMD z-score was < or = -2.0. BMD z-score was significantly different between males and females for the group (-1.75 +/- 1.06 vs. -1.08 +/- 1.00), respectively. Children and young adults with CD have a high prevalence of low BMD and routine evaluation by DXA is indicated. In patients with a chronological age-based BMD z-score < or = -2.0, a bone age-based BMD should be considered.