Radial bone mineral content of normal Japanese infants and prepubertal children: influence of age,sex and body size

The present study was performed to measure appendicular bone mass of Japanese infants and children, and to assess the influence of age, sex and body size on bone mass during the period of bone growth. The bone mineral content (BMC) and bone width (BW) at the distal third of the radius were measured by single photon absorptiometry (SPA) in 229 healthy Japanese infants and children aged 0–12 years, and the BMC/BW ratio was calculated to give the bone mineral density (BMD). BMC and BW increased with age until 2 years, while BMD did not obviously change until 2 years. After 2 years of age, the overall effect of aging appeared more prominent in BMC and BMD than in BW. There were no significant differences in BMC, BW and BMD between males and females aged 0–12 years. Age, body height, and body weight were strongly correlated with three parameters of bone mass (BMC, BW, and BMD). Among the three parameters of bone mass, BMC showed the highest Pearson coefficient of correlation with age (r = 0.955), body height (r = 0.957) and body weight (r = 0.966), as compared with BW and BMD. The present cross-sectional study provides normative data of the appendicular bone mass in healthy Japanese children, which may serve as a standard for assessment of bone mineralization in Japanese infants and children with medical problems.     

Age, sex, and grip strength determine architectural bone parameters assessed by peripheral quantitative computed tomography (pQCT) at the human radius

The purpose of this study was to estimate the relation of some noninvasively derived mechanical characteristics of radial bone including architectural parameters for bone strength to grip strength and muscle cross-section. Sixty-three males between 21 and 78yr of age and 101 females between 18 and 80yr of age were measured at the nondominant forearm using peripheral quantitative computed tomography (pQCT). We assessed the integral bone mineral density (BMD(I)) and content (BMC(I)) by pQCT at the distal and at the mid-shaft radius. Integral bone area (Area(I)), cortical thickness (C-th), and a newly proposed index for bone strength; the stress-strain index (SSI) were also calculated. The dynamometrically measured maximum grip strength was taken as a mechanical loading parameter and muscle cross-section as a substitute for it. Sex, grip strength, BMC(I) and BMD(I) (distal radius) were identified in a multiple regression analysis to significantly predict bone strength as expressed by SSI, after adjusting for all other independent variables, including age and sex (p<0.0001). Grip strength was closest related to age, sex, BMD(I) and SSI(p) of the distal radius. The cross-sectional area of muscle was not significantly determining the grip strength within the analysis model. In conclusion, our results suggested that architectural parameters at the distal radius were better related to grip strength than to cross-sectional muscle area in both males and females. Maximum muscle strength as estimated by grip strength might be a stronger determinant of mechanical characteristics of bones as compared with cross-sectional muscle area.     

Protective effect of moderate overweight on bone density of the hip joint in elderly and old Austrians

The effect of weight, classified by body mass index (BMI), on bone mass (BMC) of the whole body and on bone mineral density BMD of the hip joint was analysed in a sample of 120 Austrians of Vienna and surroundings. The 68 females and 52 males of this cross sectional study ranged in age between 60 and 92 years (x = 71.7 +/- 7.7). Age distribution was not significantly different between sexes. The WHO (1997) classification of body mass index (BMI) was used for weight classification, i.e. normal weight (BMI 18.5-24.99) and moderate overweight (BMI 25.0-29.99). Obese subjects (BMI 30+) were not included in this study. Bone mass of the whole body as well as bone density of the hip joint were determined by Dual-energy-X-ray absorptiometry (DEXA) using a hologic 2000 scanner. As expected BMC and BMD values were significantly higher in males than in females. While in both females and males moderately overweight BMD of the hip was significantly higher than in those with normal BMI, statistically significant differences of BMC were restricted to females only. Such positive association between body weight and BMC and BMD is in agreement with previous studies on mature subjects, and menopausal and postmenopausal women in particular. In addition, this study demonstrates corresponding positive associations between moderate overweight and bone mass and -density in the elderly and old aged.     

Normal bone mineral content in young adults with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

OBJECTIVE: To assess bone mineral content (BMC) and body composition in adolescents and young adults with congenital adrenal hyperplasia. METHODS: BMC, anteroposterior-projected bone area (BA), bone mineral density, and fat mass percentage were determined by dual-energy X-ray absorptiometry in 18 patients aged 18-33 years (8 females and 10 males) with 21-hydroxylase deficiency using a Hologic QDR 1000/W densitometer. RESULTS: BMC and bone mineral density for age were significantly reduced at -1.2 standard deviation scores (SDS; range from -2.8 to +4.1) and -1.1 SDS (range from -3.2 to +2.6), respectively. The BA for height was significantly increased at +1.7 SDS (range from -0.5 to +4.8), and the BMC for BA was normal at 0.3 SDS (range from -2.0 to +3.6). The median final height was significantly reduced at -1.6 SDS (range from -5.6 to +0.3), and the fat mass percentage was significantly increased at +1.5 SDS (range from -1.0 to +5.0). CONCLUSION: Our study population of young adults with 21-hydroxylase deficiency had a short stature and broad bones with a normal BMC and had an increased fat mass percentage.     

Aged-Related Changes in Body Composition and Association between Body Composition with Bone Mass Density by Body Mass Index in Chinese Han Men over 50-year-old

Objectives

Aging, body composition, and body mass index (BMI) are important factors in bone mineral density (BMD). Although several studies have investigated the various parameters and factors that differentially influence BMD, the results have been inconsistent. Thus, the primary goal of the present study was to further characterize the relationships of aging, body composition parameters, and BMI with BMD in Chinese Han males older than 50 years.

Methods

The present study was a retrospective analysis of the body composition, BMI, and BMD of 358 Chinese male outpatients between 50 and 89 years of age that were recruited from our hospital between 2009 and 2011. Qualified subjects were stratified according to age and BMI as follows: 50–59 (n = 35), 60–69 (n = 123), 70–79 (n = 93), and 80–89 (n = 107) years of age and low weight (BMI: < 20 kg/m²; n = 21), medium weight (20 ≤ BMI < 24 kg/m²; n = 118), overweight (24 ≤ BMI < 28 kg/m²; n = 178), and obese (BMI ≥ 28 kg/m²; n = 41). Dual-energy X-ray absorptiometry (DEXA) was used to assess bone mineral content (BMC), lean mass (LM), fat mass (FM), fat-free mass (FFM), lumbar spine (L1-L4) BMD, femoral neck BMD, and total hip BMD. Additionally, the FM index (FMI; FM/height²), LM index (LMI; LM/height²), FFM index (FFMI; [BMC+LM]/height²), percentage of BMC (%BMC; BMC/[BMC+FM+LM] × 100%), percentage of FM (%FM; FM/[BMC+FM+LM] × 100%), and percentage of LM (%LM; LM/(BMC+FM+LM) × 100%) were calculated. Osteopenia or osteoporosis was identified using the criteria and T-score of the World Health Organization.

Results

Although there were no significant differences in BMI among the age groups, there was a significant decline in height and weight according to age (p < 0.0001 and p = 0.0002, respectively). The LMI and FFMI also declined with age (both p < 0.0001) whereas the FMI exhibited a significant increase that peaked in the 80-89-years group (p = 0.0145). Although the absolute values of BMC and LM declined with age (p = 0.0031 and p < 0.0001, respectively), there was no significant difference in FM. In terms of body composition, there were no significant differences in %BMC but there was an increase in %FM (p < 0.0001) and a decrease in %LM (p < 0.0001) with age. The femoral neck and total hip BMD significantly declined with age (p < 0.0001 and p = 0.0027, respectively) but there were no differences in L1-L4. BMD increased at all sites (all p < 0.01) as BMI increased but there were declines in the detection rates of osteoporosis and osteopenia (both p < 0.001). A logistic regression revealed that when the medium weight group was given a BMI value of 1, a decline in BMI was an independent risk factor of osteoporosis or osteopenia, while an increase in BMI was a protective factor for BMD. At the same time, BMD in L1-L4 exhibited a significant positive association with FMI (p = 0.0003) and the femoral neck and total hip BMDs had significant positive associations with FFMI and LMI, respectively (both p < 0.0001).

Conclusions

These data indicate that LMI and FFMI exhibited significant negative associations with aging in Chinese Han males older than 50 years, whereas FMI had a positive association. BMD in the femoral neck and total hip declined with age but an increased BMI was protective for BMD. LMI and FFMI were protective for BMD in the femoral neck and total hip.     

Growth and nutritional status of Khasi boys in Northeast India relating to exogamous marriages and socioeconomic classes

The Khasis are one of the matrilineal tribes of Meghalaya in Northeast India. They belong to the Indo-Mongoloid racial stock, and speak the Monkhmer language of the Austro-Asiatic group. They have their own traditional religion (Niam Khasi), but about 65% of them have converted to Christianity. A few Khasi members have also embraced Islam through matrimonial relationship with immigrant Muslim males. The present study was based on a cross-sectional sample of 1,351 urban Khasi boys aged 3-18 years belonging to these three religious groups, with a view to understanding the effects of socioeconomic factors on growth and nutritional status, using anthropometric variables such as weight and height. The findings showed that about 60%, 29%, and 6% of these boys were below -2 Z-scores of the US National Center for Health Statistics (NCHS) references in respect of weight for age, height for age, and body mass index for age, respectively. The logistic regression coefficient (beta +/- standard error) indicated that the prevalence of low weight for age (below -2 Z-scores of the NCHS references) was positively associated with age (0.088 +/- 0.014, P<0.0001), while it was inversely associated with household income (-1.216 +/- 0.030, P<0.0001). Likewise, low height for age Z-score was negatively associated with household income (-1.056 +/- 0.130, P<0.0001), although such a relationship was not significant in the case of low body mass index for age (-0.169 +/- 0.229, P>0.05). There were also significant differences between religious groups in respect of anthropometric variables. Allowing for household income, the ANCOVA test indicated that Muslim Khasi boys, who were the offspring of intermarriages between Khasi females and immigrant Muslim males, were significantly heavier and taller than Christian and Niam Khasi boys almost across ages. From about 3-10 years of age, Muslim Khasi boys were, on average, comparable to the 5th and 25th percentiles of the NCHS references of height and weight, respectively. Although it looks as though genetic mechanisms like heterosis and/or gene flow might also be associated with the larger body size in Muslim boys, such a conjecture could only be substantiated or refuted by further studies concerning genetic and more socioeconomic data on both immigrant and nonimmigrant populations.     

Sexual dimorphism in schoolchildren of the Villa IAPI neighborhood (Quilmes,Buenos Aires,Argentina)

Villa IAPI is a poor neighborhood of about 5,000 inhabitants in the overpopulated conurbano bonaerense at the outskirts of the city of Buenos Aires. Most of the adult male residents are construction workers; the rest are temporary workers, underemployed, or unemployed. The inhabitants of Villa IAPI suffer the effects of many adverse socio-economic conditions, including poor nutrition, deficient sanitation, and inadequate medical care. Seven anthropometric variables were measured on 765 children from 6 to 14 years old to test for the presence of an altered pattern of sexual dimorphism. It was found that there were practically no sex differences in standing height and upper-arm muscle circumference. In some age groups, there was a weak but significant sexual dimorphism in body weight and sitting height. The greatest and most persistent dimorphism was found in head circumference, and in triceps and subscapular skinfolds. In all except two age groups, head circumference in males was significantly greater than in females. The other dimorphic variables (body weight, sitting height, and triceps and subscapular skinfolds) showed the opposite relationship. Essentially, females showed increments in subcutaneous fat, while reduced growth in muscle and bone was evident in males. The hypothesis of “better female canalization” can explain the altered dimorphic pattern found in the malnourished Villa IAPI population. © 1993 Wiley-Liss, Inc.     

Familial, structural, and environmental correlates of MRI-defined bone marrow lesions: a sibpair study

The aim of this study was to estimate the heritability and describe the correlates of bone marrow lesions in knee subchondral bone. A sibpair design was used. T2- and T1-weighted MRI scans were performed on the right knee to assess bone marrow lesions at lateral tibia and femora and medial tibia and femora, as well as chondral defects. A radiograph was taken on the same knee and scored for individual features of osteoarthritis (radiographic osteoarthritis; ROA) and alignment. Other variables measured included height, weight, knee pain, and lower-limb muscle strength. Heritability was estimated with the program SOLAR (Sequential Oligogenetic Linkage Analysis Routines). A total of 115 siblings (60 females and 55 males) from 48 families, representing 95 sib pairs, took part. The adjusted heritability estimates were 53 ± 28% (mean ± SEM; p = 0.03) and 65 ± 32% (p = 0.03) for severity of bone marrow lesions at lateral and medial compartments, respectively. The estimates were reduced by 8 to 9% after adjustment for chondral defects and ROA (but not alignment). The adjusted heritability estimate was 99% for prevalent bone marrow lesions at both lateral and medial compartments. Both lateral and medial bone marrow lesions were significantly correlated with age, chondral defects, and ROA of the knee (all p < 0.05). Medial bone marrow lesions were also more common in males and were correlated with body mass index (BMI). Thus, bone marrow lesions have a significant genetic component. They commonly coexist with chondral defects and ROA but only share common genetic mechanisms to a limited degree. They are also more common with increasing age, male sex, and increasing BMI.     

Relationships between anthropometric, body composition and bone mineral parameters in 7-8-year-old rhythmic gymnasts compared with controls

The aim of the study was to investigate the relationships between specific anthropometric (9 skinfolds, 13 girths, 8 lengths and 8 breadths), body composition (body fat %, fat free mass [FFM], fat mass [FM]) parameters and bone mineral parameters (bone mineral density [BMD], bone mineral content [BMC) in young rhythmic gymnasts and same age controls. Eighty nine 7-8-year-old girls participated in this study and were divided to the rhythmic gymnast's (n = 46) and control (n = 43) groups. Body composition was determined by dual energy X-ray absorptiometry (FFM, FM, body fat %, BMD and BMC). Body fat % and FM were lower and BMD and BMC values at lumbar spine (L2-L4) and femoral neck were higher in rhythmic gymnasts compared with controls. All measured skinfold thicknesses were thicker in controls. In girths, lengths and widths there were only few significant differences between the groups. Stepwise multiple regression analysis indicated that skinfold thicknesses (supraspinale and medial calf) influenced L2-L4 BMD only in controls 38.2% (R2x100). Supraspinale and iliac crest skinfold thicknesses characterised L2-L4 BMC 43.9% (R2x100). Calf girths influenced BMD in L2-L4 52.3% (R2x100) in controls. BMC in L2-L4 was dependent only on mid-thigh girths 35.9% (R2x100). BMD in L2-L4 was dependent on tibiale-laterale height 30.0% (R2x100). Biiliocristal breadths together with sitting height characterised BMC in L2-L4 BMD 62.3% (R2x100). In conclusion, we found that the relationships between anthropometry, body composition and bone parameters in young rhythmic gymnasts are weak. In control group first of all lower body anthropometric parameters significantly correlated with BMD and BMC in spine.     

Reference ranges of urinary biomarkers of oxidized guanine in (2'-deoxy)ribonucleotides and nucleic acids

This study was aimed at defining the reference ranges for biomarkers of oxidized guanine in (2'-deoxy)ribonucleotides and nucleic acids from a large Italian sample. We recruited 300 healthy subjects (150 males; mean age 44.1±13.6years; 26% smokers) without any known exposure to occupational oxidizing agents. They were asked to provide a spot urine sample, on which the following markers were determined by liquid chromatography-tandem mass spectrometry: 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), 8-oxo-7,8-dihydroguanine (8-oxoGua), and cotinine. The reference ranges, estimated as the 5th-95th percentiles of creatinine-normalized values (pmol/μmol(creat)) were 0.7-4.2, 0.9-4.7, and 5.6-120.7 for 8-oxodGuo, 8-oxoGuo, and 8-oxoGua, respectively. Oxidation biomarkers were correlated with one another (p<0.005) and with urinary creatinine (p<0.0001). Males excreted significantly higher concentrations of 8-oxoGua than females (p<0.0001). 8-OxoGua and 8-oxoGuo showed a positive association with age (p<0.001), also after stratification by gender. Multiple linear regression models including urinary creatinine concentration, age, and smoking habit as independent variables showed a significant effect of age, but not of smoking, on the levels of 8-oxoGuo in males (p<0.0001) and of both 8-oxoGuo and 8-oxoGua in females (p<0.0001). A preliminary assessment in a small group (n=25) of patients affected by advanced non-small-cell lung cancer and receiving platinum-based chemotherapy showed significantly higher values of both 8-oxoGuo and 8-oxodGuo (p<0.0001 for both) compared to the referent population.     

Effect of subclinical hypothyroidism and obesity on whole-body and regional bone mineral content

OBJECTIVE: The present investigation was aimed to evaluate the effect of subclinical hypothyroidism and obesity on bone mineral content (BMC) in different body segments. METHODS: Thirty-two premenopausal women (age: 37 +/- 9.9 years), with a wide range in body mass index (BMI), were studied. Subclinical hypothyroidism was defined by a basal TSH > or = 4 microU/l and/or a TRH-stimulated peak > or = 30 microU/l. For each subject, weight, height, BMI (weight/height(2)) and the waist/hip ratio were measured. Total BMC, total bone mineral density (BMD), leg BMC, leg BMD, trunk BMC, trunk BMD, arm BMC and arm BMD were determined using dual-energy X-ray absorptiometry. Thyroid function (basal and TRH-stimulated TSH, free T(3) and free T(4)) were determined from fasting blood samples for all subjects. RESULTS: Anova was conducted within all the groups to observe the effect of thyroid status and/or obesity on BMC and BMD. There was no statistical difference for age. Total BMC was affected by obesity (p < 0.05) but not by thyroid status, BMD of the legs was significantly influenced both by thyroid function and obesity (p < 0.01); total BMD was affected by hypothyroid status (p < 0.05). A direct relationship between leg BMD and TSH was demonstrated. CONCLUSION: Subclinical thyroid hypofunction and obesity seem to affect BMD differently in the body segments. An influence of gravitational force seems necessary in order to make evident the effect of subclinical hypothyroidism on bone. A condition of subclinical hypothyroidism should be considered when evaluating subjects for osteoporosis, since a BMD measured at the femoral neck may induce underestimation of initial osteoporosis.     

Relationship of handgrip strength with anthropometric and body composition variables in prepubertal children

The purpose of the present study was to examine the relationship of handgrip strength with basic anthropometric variables, hand anthropometric variables, total body and hand composition, total body and hand bone mineral density (BMD) and bone mineral content (BMC) in prepubertal children aged between 8 and 11 years (n=64, 27 boys, 37 girls). Height and body mass were measured and body mass index (BMI kg/m²) was calculated. Biceps and triceps skinfolds, arm relaxed, arm flexed, forearm and wrist girths, acromiale-radiale, radiale-stylion-radiale and midstylion-dactylion length and humerus breadth were measured. Specific hand anthropometric variables according to Visnapuu and Jürimäe [2007. Handgrip strength and hand dimensions in young handball and basketball players. J. Strength Cond. Res. 21, 923-929] were used. Five fingers’ spans, fingers’ lengths and perimeters of the hand were measured. Total body and right-hand fat percentage, fat mass and lean mass (LBM) were measured by dual-energy X-ray absorptiometry (DXA). Right-hand BMC and BMD were analysed from the bone variables. Maximal handgrip strength of the right hand was measured with the hand dynamometer. Stepwise multiple regression analysis indicated that the most important predictive value from the basic anthropometric variables was body height, explaining 76.1% (R²×100), 40.7% and 50.6% of the handgrip strength in boys, girls and total group, respectively. Measured skinfold thicknesses and breadths were not related to handgrip strength in any group. Forearm girths significantly predicted handgrip strength in boys (30.8%), girls (43.4%) and total group (43.4%). As a rule, handgrip strength was more dependent on the anthropometric and body composition variables in boys than girls. It was concluded that body height, forearm girth, midstylion-dactylion and acromiale-radiale length and hand LBM and BMC are the most limiting factors influencing handgrip strength in prepubertal children.     

How cancellous and cortical bones adapt to loading and growth hormone

There is great interest in the relationships between growth hormone (GH), muscle loading and bone, in part, because GH increases muscle mass which provides the largest signals that control bone modeling and remodeling. This study was designed to examine the effects of GH and muscle loading by exercise (EX) independently and in combination on bone and skeletal muscle. Thirteen-month-old female F344 rats were divided into 6 groups: Group 1, baseline controls (B); Group 2, agematched controls (C); Group 3, GH treated (2.5 mg rhGH/kg b. wt/day, 5 days per week); Group 4, voluntary wheel running exercise (EX); Group 5, GH+EX, and rats in Group 6 were food restricted (FR) to lower their body weight and examine the effects of decreased muscle load on bone. All animals, except the baseline controls, were sacrificed after 4.5 months. Growth hormone increased the body weight and tibial muscle mass of the rats markedly, while EX caused a slight decrease in body weight and partially inhibited the increase caused by GH in the GH+EX group. Food restriction greatly decreased body weight below that of age-matched controls but neither FR nor EX had a significant effect on the mass of the muscles around the tibia. Growth hormone and EX independently increased tibial diaphyseal cortical bone area (p<0.0001), cortical thickness (p<0.0001), cortical bone mineral content (p<0.0001), periosteal perimeter (p<0.0001) and bone strength-strain index (SSI) (p<0.0001). The effects of GH were more marked, and the combination of GH and EX produced additive effects on many of the tibial diaphyseal parameters including bone SSI. GH+EX, but not GH or EX alone caused a significant increase in endocortical perimeter (p<0.0001). In the FR rats, cortical bone area and cortical mineral content increased above the baseline level (p<0.0001) but were below the levels for age-matched controls (p<0.0001). In addition, marrow area, endocortical perimeter and endocortical bone formation rate increased significantly in the FR rats (p<0.01, p<0.0001, p<0.0001). Three-point bending test of right tibial diaphysis resulted in maximum force (Fmax) values that reflected the group differences in indices of tibial diaphyseal bone mass except that GH+EX did not produce additive effect on Fmax. The latter showed good correlation with left tibial diaphyseal SSI (r=0.857, p<0.0001) and both indices of bone strength correlated well with tibial muscle mass (r=0.771, Fmax; r=0.700, SSI; p<0.0001). We conclude that the bone anabolic effects of GH with or without EX may relate, in part, to increased load on bone from tibial muscles and body weight, which were increased by the hormone. The osteogenic effects of EX with or without GH may relate, in part, to increased frequency of muscle load on bone as EX decreased body weight (p<0.05) but had no significant effect on tibial muscle mass. The enhanced loss of endocortical bone by FR may relate, in part, to decreased load on bone due to low body weight (p<0.0001) as FR did not cause a significant decrease in tibial muscle mass (p=0.357). The roles of humoral and local factors in the bone changes observed remain to be established.     

Tooth,chin, bone and body size correlations

Correlations of size of teeth, chin, bone and body were investigated in 118 males and 102 females of the Burlington Growth Centre. In the males, the mesiodistal widths of the mandibular lateral incisors and canines were independently related to the thickness of the cortex of the second metacarpal and to body weight. Bone cortex thickness was significantly related to metacarpal width in males and to body weight in females. Chin depth of the males was significantly related to bone width and to body height, and negatively related to tooth width when bone width or body weight was held constant in partial correlations. Bone width and length were significantly related to body height in both sexes.     

Influence of insulin-like growth factor-1 and leptin on bone mineral content in healthy premenopausal women

The aim of the present investigation was to study the influence of plasma insulin-like growth factor-1 (IGF-1) and leptin levels on bone mineral mass (BMC) and bone mineral density (BMD) in premenopausal women and the relationship between IGF-1 and leptin levels. Two hundred and four healthy women participated in this study. All participants had a body mass index (BMI) <30 kg/m(2) and were matched for their level of mean daily energy expenditure. BMC and BMD were correlated with measured body composition and blood biochemical parameters. No association was observed between BMC and BMD values with measured physical performance characteristics. Leptin had a significant association with BMC (beta = 0.840; P = 0.0001), total BMD (beta = 0.833; P = 0.0001), femoral neck BMD (beta = 0.829; P = 0.0001), and lumbar spine BMD (beta = 0.833; P = 0.0001). However, these associations were no longer independent when adjusted for body fat mass (FM) and trunk fat:leg fat ratio (P > 0.385). IGF-1 was significantly related to BMC (beta = 0.920; P = 0.0001), total BMD (beta = 0.918; P = 0.0001), femoral neck BMD (beta = 0.921; P = 0.0001), and lumbar spine BMD (beta = 0.917; P = 0.0001), but did not remain significant when adjusted for fat free mass (FFM; P > 0.062). In addition, a significant association between IGF-1 and leptin was found (beta = 0.801; P = 0.0001), and it remained significant after controlling for age, FM, FFM, insulin, and fasting insulin resistance index (FIRI), but not when adjusted for BMC and body mass values. In conclusion, it appears that fasting IGF-1 and leptin concentrations have no direct effect on BMC and BMD values. In addition, if there is an important relationship between IGF-1 and leptin, it is mediated or confounded by BMC in premenopausal women.     

Lumbar ontogenetic allometry and dimorphism in humans. A case for comparison between interspecific and intraspecific scaling

The ontogenetic allometry of the lumbar region of 1913 humans (1228 females and 685 males), ranging from newborn to 21-year-old individuals, was studied by means of length, width, projected surface area and bone mineral density of the segment L2 - L4, obtained by dual X-ray absorptiometry (DXA). All these parameters were regressed to body mass and height of the individuals, considered alternatively as the independent variable. Firstly, we addressed the comparison between the results obtained on both sexes in order to elucidate whether ontogenetic differences existed. Length of the segments increased significantly faster in females than in males, independently whether the regression was made against body mass or height, while in both types of regression width scaled in males faster than in females. Regarding bone mineral density, although males increased bone mineral density faster than females, slope differences were not significant. However, y-interception was significantly higher in females than in males when bone mineral density was regressed to body mass. Results on length and width are compared with others from previous research on allometry. Finally, global results are discussed as regards the slope predictions for interspecific scaling.     

What happens to children when they grow up? How does the human body change after the age of 18

The present study answers the question on how the human body changes in two successive decades after its final height had been reached. One hundred and three individuals (56 males and 47 females) who were followed up longitudinally by a team of scientists from birth to 18 years of age were investigated anthropometrically by 18 body measurements again when they reached the age of between 35 and 39 years. The Carter-Heath somatotype was ascertained as a part of the study. The results of the investigation at the age of 35 to 39 years were compared with the Czech Standard and with those from 18 years of age. The means of all measurements in both sexes increased with age (with the exception of stature in females). Relative measurements and indices, which were calculated only in the groups of 35-39 year-olds were all on the average greater in males than in females with the exception of relative head circumferences and pelvis width, in the pelvis width in per cent of biacromial width, in the sum of skinfolds, and in the gross percent of body fat. Males as well as females increased from the age of 18 to 35-39 as a rule in weight, muscle, bone and fat mass, which were manifested by a shift towards endomorphic and mesomorphic components of their somatotypes away from the ectomorphic one.     

Potassium per kilogram fat-free mass and total body potassium: predictions from sex,age, and anthropometry

Total body potassium (TBK) is located mainly intracellularly and constitutes an index of fat-free mass (FFM). The aim was to examine whether TBK and the TBK-to-FFM ratio (TBK/FFM) can be estimated from sex, age, weight, and height. A primary study group (164 males, 205 females) and a validation group (161 and 206), aged 37-61 yr, were randomly selected from the general population. TBK was determined by whole body counting, and FFM was obtained by dual-energy X-ray absorptiometry (DEXA; FFM(DEXA)). The primary study group was used to construct sex-specific equations predicting TBK and TBK/FFM from age, weight, and height. The equations were used to estimate TBK and TBK/FFM in the validation group. The estimates were compared with measured values. TBK in different age ranges was predicted, with errors ranging from 5.0 to 6.8%; errors for TBK/FFM ranged from 2.7 to 4.8%, respectively. By adding FFM(DEXA) as a fourth predictor, the error of the TBK prediction decreased by approximately two percentage units. In conclusion, TBK and TBK/FFM can be meaningfully estimated from sex, age, weight, and height.     

Long-term experiment to study the development, interaction, and influencing factors of DEXA parameters

Dual-energy X-ray absorption (DEXA) is commonly used to measure bone mineral density (BMD), bone mineral content (BMC), and body composition data (fat mass and lean mass) for phenotype assessment in mice. We were interested in the long-term development of BMD, BMC, lean mass, and fat mass of mice, also taking into account sex and genetic background. The dataset was used to analyze correlations among the different parameters. We analyzed males and females from inbred strains C3HeB/FeJ and C57BL/6J, starting from 42 until 528 days of age. To evaluate the effect of husbandry systems, we repeated a part of the study in a second facility with a different caging system. We also assessed different DEXA settings and repeatability of the scans. The results of this study were used to draw conclusions for the use of DEXA analysis in mouse phenotyping approaches.     

Measurement of bone mineral content in vivo using photon absorptiometry

Progress in evaluating treatment of systemic bone disease has been hampered in the past by lack of precise in vivo quantitative techniques. Recently a method has been developed for measurement of bone mineral content (BMC), based on bone absorption of low-energy monochromatic radiation. This paper discusses a technique of photon absorptiometry using ¹²⁵l as a collimated point source. The technique is simple, with accuracy and precision within 2%.BMC and bone width (W) were measured in the distal radius of 359 normal subjects ranging in age from 5 to 82 years. A “normal” curve of BMC/W with age as the independent variable was then obtained from this population and was constructed for each sex. A positive correlation of BMC/W with height and body weight was found in a group of normal males.A series of patients with osteoporosis or malabsorption, or undergoing hemodialysis or steroid treatment, was then assessed in order to demonstrate changes in BMC/W that may occur secondary to disease or disturbances in calcium metabolism. Many of these patients were found to have a BMC/W below the normal mean value for their age and sex.