Relationship between body composition and bone mineral content in young and elderly women

PRIMARY OBJECTIVE: To study the relationship between bone mineral content (BMC), lean tissue mass (LTM) and fat mass (FM) in a large sample of young and elderly women. RESEARCH DESIGN: Cross-sectional. METHODS AND PROCEDURES: BMC, LTM and FM were measured by dual-energy X-ray absorptiometry in 2009 free-dwelling Caucasian women aged 63 +/- 7 years (mean +/- SD; range: 37-88 years). The majority of women were postmenopausal (96%). RESULTS: LTM explained 13% more variance of BMC than FM (R(2)(adj) = 0.39 vs 0.26, p < 0.0001) but weight (Wt) explained 5% more variance of BMC than LTM (R(2)(adj) = 0.44, p < 0.0001). The prediction of BMC obtained from LTM and FM (R(2)(adj)= 0.46, p < 0.0001) was only slightly better than that obtained from Wt. After the effects of age, Wt and height (Ht) on BMC were taken into account by multiple regression, the contribution of LTM and FM to BMC was just one-fifth of that of Wt (R(2)(adj) for full models < or =0.56, p < 0.0001). After a further correction for bone area (BA), the contribution of LTM and FM to BMC was just one-tenth of that of BA and not different from that of Wt and Ht on practical grounds (R(2)(adj) for full models = 0.84, p < 0.0001). Thus, after inter-individual differences in age, Wt, Ht (and bone size) are taken into account, the relationship between body composition and BMC is substantially weakened. CONCLUSIONS: In Caucasian women, (1) LTM is a stronger predictor of BMC than FM, but (2) Wt is a better predictor of BMC than body composition for practical purposes, and (3) Wt and body composition are not able to explain more than 46% of BMC variance.     

Anthropometry fails in classifying bonemineral status in postmenopausal women

This study tested two hypotheses: (1) that simple anthropometric parameters can be used to identify patients at risk of decreased bonemineral content and (2) that an inverse relationship exists between waist:hip ratio (WHR) and bonemineral density (BMD). Bonemineral content (BMC) and BMD were evaluated by dual-energy X-ray absorptiometry in 1873 free-living women. Of these, 1819 (97%) were post-menopausal. One thousand and thirteen women (54%) had normal BMD, 705 (38%) osteopenia and 155 (8%) osteoporosis. Body weight (Wt), body mass index and arm muscle and fat areas were significantly lower in osteoporotics than osteopenics (p &;lt; 0.0001) and in these latter than controls (p &;lt; 0.0001). However, values of WHR were similar in all groups (p = ns). Body weight was the anthropometric parameter better correlated with BMC (rho= 0.650, p &;lt; 0.0001) and only Wt and age were identified as significant predictors of bonemineral status (normal-BMD/osteopenic/osteoporotic) at polytomous logistic regression (p = 0.0001 for each). However, Wt could not be employed as an indicator of bone mineral status at the individual level because of high variations in BMC for the same level of Wt. Under- (&;lt; 5th percentile) and normal-Wt (5th-95th percentile) women had the same frequency of osteopenia (39%) while it was lower in over-Wt (&;gt; 95th) women (13%). The frequency of osteoporosis was higher in under- than normal-Wt women (37 vs 7%) and none of the over-Wt women had osteoporosis. This study shows that: (1) simple anthropometric measurements cannot be used to select subjects at risk of decreased BMC and, (2) BMD does not vary with WHR.     

Anthropometry fails in classifying bone mineral status in postmenopausal women

This study tested two hypotheses: (1) that simple anthropometric parameters can be used to identify patients at risk of decreased bone mineral content and (2) that an inverse relationship exists between waist:hip ratio (WHR) and bone mineral density (BMD). Bone mineral content (BMC) and BMD were evaluated by dual-energy X-ray absorptiometry in 1873 free-living women. Of these, 1819 (97%) were post-menopausal. One thousand and thirteen women (54%) had normal BMD, 705 (38%) osteopenia and 155 (8%) osteoporosis. Body weight (Wt), body mass index and arm muscle and fat areas were significantly lower in osteoporotics than osteopenics (p < 0.0001) and in these latter than controls (p < 0.0001). However, values of WHR were similar in all groups (p = ns). Body weight was the anthropometric parameter better correlated with BMC (rho = 0.650, p < 0.0001) and only Wt and age were identified as significant predictors of bone mineral status (normal-BMD/osteopenic/osteoporotic) at polytomous logistic regression (p = 0.0001 for each). However, Wt could not be employed as an indicator of bone mineral status at the individual level because of high variations in BMC for the same level of Wt. Under- (< 5th percentile) and normal-Wt (5th-95th percentile) women had the same frequency of osteopenia (39%) while it was lower in over-Wt (> 95th) women (13%). The frequency of osteoporosis was higher in under- than normal-Wt women (37 vs 7%) and none of the over-Wt women had osteoporosis. This study shows that: (1) simple anthropometric measurements cannot be used to select subjects at risk of decreased BMC and, (2) BMD does not vary with WHR.     

Cross-calibration of eight-polar bioelectrical impedance analysis versus dual-energy X-ray absorptiometry for the assessment of total and appendicular body composition in healthy subjects aged 21-82 years

Aim: To calibrate eight-polar bioelectrical impedance analysis (BIA) against dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition in healthy adults. Research design: A cross-sectional study was carried out. Subjects: Sixty-eight females and 42 males aged 21-82 years participated in the study. Methods: Whole-body fat-free mass (FFM) and appendicular lean tissue mass (LTM) were measured by DXA; resistance ( R ) of arms, trunk and legs was measured by eight-polar BIA at frequencies of 5, 50, 250 and 500 kHz; whole-body resistance was calculated as the sum R of arms, trunk and legs. Results: The resistance index (RI), i.e. the height 2 /resistance ratio, was the best predictor of FFM and appendicular LTM. As compared with weight (Wt), RI at 500 kHz explained 35% more variance of FFM ( vs 0.57), 45% more variance of LTM arm ( vs 0.48) and 36% more variance of LTM leg ( vs 0.50) ( p < 0.0001 for all). The contribution of age to the unexplained variance of FFM and appendicular LTM was nil or negligible and the RI &#50 sex interactions were either not significant or not important on practical grounds. The percent root mean square error of the estimate was 6% for FFM and 8% for LTM arm and LTM leg. Conclusion: Eight-polar BIA offers accurate estimates of total and appendicular body composition. The attractive hypothesis that eight-polar BIA is influenced minimally by age and sex should be tested on larger samples including younger individuals.     

Cross-calibration of eight-polar bioelectrical impedance analysis versus dual-energy X-ray absorptiometry for the assessment of total and appendicular body composition in healthy subjects aged 21-82 years

AIM: To calibrate eight-polar bioelectrical impedance analysis (BIA) against dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition in healthy adults. RESEARCH DESIGN: A cross-sectional study was carried out. SUBJECTS: Sixty-eight females and 42 males aged 21-82 years participated in the study. METHODS: Whole-body fat-free mass (FFM) and appendicular lean tissue mass (LTM) were measured by DXA; resistance (R) of arms, trunk and legs was measured by eight-polar BIA at frequencies of 5, 50, 250 and 500 kHz; whole-body resistance was calculated as the sum R of arms, trunk and legs. RESULTS: The resistance index (RI), i.e. the height(2)/resistance ratio, was the best predictor of FFM and appendicular LTM. As compared with weight (Wt), RI at 500 kHz explained 35% more variance of FFM (vs 0.57), 45% more variance of LTM(arm) (vs 0.48) and 36% more variance of LTM(leg) (vs 0.50) (p < 0.0001 for all). The contribution of age to the unexplained variance of FFM and appendicular LTM was nil or negligible and the RI x sex interactions were either not significant or not important on practical grounds. The percent root mean square error of the estimate was 6% for FFM and 8% for LTM(arm) and LTM(leg). CONCLUSION: Eight-polar BIA offers accurate estimates of total and appendicular body composition. The attractive hypothesis that eight-polar BIA is influenced minimally by age and sex should be tested on larger samples including younger individuals.     

Effects of long-term tennis playing on the muscle-bone relationship in the dominant and nondominant forearms.

The relationship between muscle strength and bone mineral density illustrates the positive effect of mechanical loading on bone. But local and systemic factors may affect both muscle and bone tissues. This study investigated the effects of long-term tennis playing on the relationship between lean tissue mass and bone mineral content in the forearms, taking the body dimensions into account. Fifty-two tennis players (age 24.2 +/- 5.8 yrs, 16.2 +/- 6.1 yrs of practice) were recruited. Lean tissue mass (LTM), bone area, bone mineral content (BMC), and bone mineral density were measured at the forearms from a DXA whole-body scan. Grip strength was assessed with a dynamometer. A marked side-to-side difference (p < 0.0001) was found in favor of the dominant forearm in all parameters. Bone area and BMC correlated with grip strength on both sides (r = 0.81-0.84, p < 0.0001). The correlations were still significant after adjusting for whole-body BMC, body height, or forearm length. This result reinforced the putative role of the muscles in the mechanical loading on bones. In addition, forearm BMC adjusted to LTM or grip strength was higher on the dominant side, suggesting that tennis playing exerts a direct effect on bone.     

Relationships between blood pressure,anthropometric characteristics and blood lipids in high- and low-altitude populations from Central Asia

We studied the relationships between blood pressure, anthropometric characteristics and blood lipids in 72 low altitude (LA) Uighurs (600m), 91 LA-Kirghizs (900 m), 117 medium altitude (MA) Kazakhs (2100m) and 94 high altitude (HA) Kirghizs (3200 m). All subjects were male and had a similar age (p = ns, ANOVA; range for all 374 subjects: 18-66 yr). Body weight (Wt), body mass index (BMI) and the sum of four skinfolds (4SF) were significantly lower in HA-Kirghizs than the remaining groups (p &lt; 0:0005, p &lt; 0:0005 and p &lt; 0:05 respectively, ANOVA). However, no difference was found in body fat distribution as detected by waist: hip circumference (WHR) and triceps : subscapular skinfold ratios (TSR; p = ns, ANOVA). Stage 1 hypertension was detected in 18% of LA-Uighurs, 2% of LA-Kirghizs, 4% of MA-Kazakhs and 1% of HA-Kirghizs; stage 2 hypertension was detected in 2% of LA-Uighurs and none of the remaining groups; no subject had stage 3 hypertension (The Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure 1997). Blood cholesterol (CH) and triglycerides (TG) did not differ between groups (p = ns, ANOVA). The relationships between systolic (SBP) or diastolic (DBP) blood pressure and age, Wt, BMI, 4SF, WHR, TSR, CH and TG were independent from altitude (p = ns, ANCOVA). In the pooled sample (n = 374), age explained 1 and 3% of SBP (p &lt; 0:05) and DBP (p &lt; 0:005) variance respectively, Wt was the best predictor of SBP and DBP explaining 11 and 10% of their variance respectively (p &lt; 0:0001) and CH explained 5% of DBP variance (p &lt; 0:0001). In conclusion, hypertension is more frequent in LA- than MA- and HA-subjects from Central Asia. However, anthropometric characteristics and blood lipids do similarly contribute to explain blood pressure in these subjects.

An Bewohnern des Tieflandes (LA), mittlerer Hohen (MA) und an Hochlandbevolkerungen (HA) wurde der Zusammenhang zwischen dem Blutdruck, anthropometrischen Charakteristika und Blutlipiden untersucht. Im einzelnen handelt es sich bei den untersuchten Bevolkerungen um 72 LA-Uiguren (600m), 91 LA-Kirgis (900 m), 117 MA-Kasaks (2100 m) und 94 HA-Kirgis (3200 m). Es handelt sich ausschliesslich um mannliche Probanden ahnlichen Alters (p = ns, ANOVA; Variationsbreite fur alle 374 Probanden: 18-66 Jahre). Das Korpergewicht (Wt), der Body Mass Index (BMI) und die Summe von vier Hautfaltendicken (4SF) war bei den HA-Kirgis signifikant niedriger als in den ubrigen Gruppen (p &lt; 0:0005; p &lt; 0:0005 bzw. p &lt; 0:05, ANOVA). In der Verteilung des Korperfetts, die uber das Verhaltnis von Taillen- zu Huftumfang (WHR) sowie das Verhaltnis von Trizeps-Hautfaltendicke zur Dicke der subskapularen Hautfalte (TSR; p = ns, ANOVA) erfasst wurde, liessen sich jedoch keine Unterschiede beobachten. Ein Bluthochdruck im Stadium 1 liess sich bei 18% der LA-Uiguren, 2% der LA.Kirgis 4% der MA-Kasaks und 1% der HA-Kirgis beobachten; ein Bluthochdruck des Stadiums 2 wurde lediglich bei 2% der LA-Uiguren beobachtet, wahrend er in den ubrigen Bevolkerungen nicht vorkam; ein Bluthochdruck des Stadiums 3 wurde in keiner Bevolkerung beobachtet (The Joint National Committee on Prevention, Detection, Evaluation and Treatment of Hypertension 1997). In den Blutkonzentrationen von Cholesterin (CH) und Triglyzeriden (TG) wurden keine Unterschiede zwischen den Gruppen beobachtet (p = ns, ANOVA). Der Zusammenhang zwischen dem systolischen (SBP) bzw. dem diastolischen Blutdruck (DBP) und dem Alter, Wt, BMI, 4SF, WHR, TSR, CH und TG war von der Hohenlage des Wohnortes unabhangig (p = ns; ANCOVA). In der gepoolten Stichprobe (n = 374), erklarte das Alter 1 bzw. 3% der Varianz des SBP (p &lt; 0:05) bzw. des DBP (p &lt; 0:005). Das Gewicht erwies sich als bester Pradiktor des SBP und DBP, es erklarte 11 bzw. 10% der Varianz (p &lt; 0:0001). CH erklarte 5% der Varianz des DBP (p &lt; 0:0001). Zusammenfassend lasst sich festhalten, dass Bluthochdruck in Zentralasien bei LA-Bevolkerungen haufiger vorkommt als in MA- und HA-Bevolkerungen. Anthropometrische Charakteristika und Blutfette tragen jedoch in ahnlicher Weise zur Erklarung des Blutdruckes bei allen Probanden bei.

On a etudie les associations entre la pression arterielle, les caracteristiques anthropometriques et les lipides sanguins chez 72 Ouigour d'altitude basse (AB) (600 m), 91 AB-Khirghiz (900 m), 117 Kazakhs d'altitude moyenne (AM) (2100m) et 94 Kirghiz d'altitude haute (AH) (3200 m). Tous les sujets etaient des hommes adultes de moyenne d'age similaire (p = ns, ANOVA; etendue de variation pour l'ensemble des 374 sujets: 18-66 ans). Le poids corporel (Pds), l'indice de masse corporelle (IMC) et la somme des quatre plis cutanes (S4PC) etaient significativement plus bas chez les AH-Kirghiz que dans les autres groupes (respectivement p &lt; 0:0005, p &lt; 0:0005 et p &lt; 0:05 ANOVA). Cependant, on n'a pas trouve de difference dans la distribution de la graisse corporelle telle que determinee par les rapports des circonferences taille/hanches (RTH) et par le rapport des plis cutanes triceps/sous-scapulaire (RTS; p = ns, ANOVA). L'hypertension de niveau 1 est presente chez 18% des AB-Ouigour, 2% des AB-Kirghiz, 4% des AMKazakh et 1% des AH-Kirghiz. Le niveau 2 d'hypertension a ete detecte chez 2% des AB-Ouigour seulement. Aucun des sujets n'avait atteint le niveau 3 d'hypertension (Comite de Prevention, Detection, Evaluation et Traitement de la Haute Pression Arterielle, 1997). Le cholesterol sanguin (CS) et les triglycerides (TG) ne differaient pas entre groupes (p = ns, ANOVA). Les associations entre pressions arterielle systolique (PAS), diastolique (PAD) et l'age, le Pds, l'IMC, la S4PC, le RTH, le RTS, le CS et les TG sont independantes de l'altitude (p = ns, ANCOVA). L'age expliquait respectivement 1 et 3% des variances de la PAS (p &lt; 0:05) et de la PSD (p &lt; 0:005), le Pds etant le meilleur predicteur de la PAS et de la PAD, expliquant respectivement 11% et 10% de leur variance (p, &lt; 0:0001), le CS expliquant 5% de la variance en PAD (p &lt; 0:0001). En conclusion, l'hypertension est plus frequente chez les sujets d'AB- que d'AM- et d'AH- en Asie Centrale. Les caracteristiques anthropometriques et les lipides sanguins contribuent demaniere semblable a expliquer la pression arterielle chez les sujets examines.     

不同甲状腺功能绝经前女性血清饥饿素与全身骨量、肌肉量、体重的相关分析

目的:探讨不同甲状腺功能的绝经前女性血清饥饿素(ghrelin)水平与其身体成份骨量(BMC)、脂肪量(FM)、肌肉量(LM)的相互关系。方法:采用放射免疫分析法检测71例不同甲状腺功能的绝经前女性其中包括甲状腺机能亢进(甲亢)组33例、甲状腺机能减低(甲减)组18例、正常对照组20例的血清饥饿素水平,同时采用化学发光快速检测法检测其血清游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、灵敏促甲状腺激素(sTSH);并采用双能X线吸收法(DXA)测定其全身身体成份(骨量、脂肪量、肌肉量),同时记录体重(BW)。结果:(1)甲亢组血清饥饿素水平明显低于正常对照组(P0.01)和甲减组(P0.01),甲减组血清饥饿素水平与正常对照组之间无显著差别(P0.05)。血清饥饿素与其FT3(r=-0.318,P0.01)、FT4(r=-0.350,P0.01)呈负相关,与sTSH(r=0.281,P0.05)呈正相关。(2)血清饥饿素与全身骨量(r=0.284,P0.05)、肌肉量(r=0.259,P0.05)、体重(r=0.279,P0.05)存在正相关;与脂肪量不存在相关(P0.05)。结论:不同甲状腺功能的绝经前女性血清饥饿素可能影响其全身骨量、肌肉量、体重。     

Relationships between blood pressure, anthropometric characteristics and blood lipids in high- and low-altitude populations from Central Asia

We studied the relationships between blood pressure, anthropometric characteristics and blood lipids in 72 low altitude (LA) Uighurs (600 m), 91 LA-Kirghizs (900 m), 117 medium altitude (MA) Kazakhs (2100 m) and 94 high altitude (HA) Kirghizs (3200 m). All subjects were male and had a similar age (p = ns, ANOVA; range for all 374 subjects: 18-66 yr). Body weight (Wt), body mass index (BM1) and the sum of four skinfolds (4SF) were significantly lower in HA-Kirghizs than the remaining groups (p < 0.0005, p < 0.0005 and p < 0.05 respectively, ANOVA). However, no difference was found in body fat distribution as detected by waist:hip circumference (WHR) and triceps:subscapular skinfold ratios (TSR; p = ns, ANOVA). Stage 1 hypertension was detected in 18% of LA-Uighurs, 2% of LA-Kirghizs, 4% of MA-Kazakhs and 1% of HA-Kirghizs; stage 2 hypertension was detected in 2% of LA-Uighurs and none of the remaining groups; no subject had stage 3 hypertension (The Joint National Committee on Prevention. Detection, Evaluation and Treatment of High Blood Pressure 1997). Blood cholesterol (CH) and triglycerides (TG) did not differ between groups (p = ns, ANOVA). The relationships between systolic (SBP) or diastolic (DBP) blood pressure and age, Wt, BMI, 4SF, WHR, TSR, CH and TG were independent from altitude (p = ns, ANCOVA). In the pooled sample (n = 374), age explained 1 and 3% of SBP (p < 0.05) and DBP (p < 0.005) variance respectively, Wt was the best predictor of SBP and DBP explaining 11 and 10% of their variance respectively (p < 0.0001) and CH explained 5% of DBP variance (p < 0.0001). In conclusion, hypertension is more frequent in LA- than MA- and HA-subjects from Central Asia. However, anthropometric characteristics and blood lipids do similarly contribute to explain blood pressure in these subjects.     

Bone mineral density in older non-Hispanic Caucasian and Mexican-American women: relationship to lean and fat mass

Primary objective: The prevalence of osteoporotic fracture is higher in non-Hispanic Caucasian (NHC) than Mexican-American (MA) women in the USA. The present study examined bone mineral density (BMD) in these two ethnic groups and the association between BMD and body composition.

Research design: Cross-sectional.

Subjects: Sixty-two NHC and 54 MA women, aged 60-86 years, with a body mass index (kgm^-2) of &lt; 30.

Methods: BMD (gcm^-2) of the spine (L_2-4), hip (femoral neck, trochanter, Ward's triangle) and whole body was determined by dual-energy X-ray absorptiometry (DXA). Bone mineral-free lean mass (LM) and fat mass (FM) and several ratios of body fat distribution were also assessed by DXA.

Results: There was no difference in age (NHC, 69.5 ± 0.7; MA 69.5 ± 0.9 years; mean ± SEM) or body mass, but MA women were shorter with a higher truncal adiposity (p < 0.001). There was no significant difference in BMD between groups, however, adjusting for height resulted in higher hip and whole body BMD in MA women (p < 0.01). When volumetric bone density was calculated (bone mineral apparent density; BMAD, g cm^?3), a trend for higher values in MA women was observed at the femoral neck (p = 0.018). LM contributed independently to BMD at the spine and hip in NHC women, with FM also contributing at the femoral neck. In MA women, LM was an independent contributor to lumbar spine and trochanter BMD, and both LM and FM contributed to whole body BMD. However, the effects of LM and FM were removed in both groups when BMD was adjusted for body or bone size, the only exception being at the trochanter in NHC women.

Conclusions: These results indicate that MA women have higher bone density at the proximal femur than NHC women, which may partially account for their lower rate of hip fracture. Further, differences in bone density between the two ethnic groups do not appear to be dependent on soft-tissue composition.     

Effects of silicone breast prostheses on the assessment of body composition by dual-energy X-ray absorptiometry.

We examined the influence of silicone breast prostheses on body composition as assessed by dual-energy X-ray absorptiometry (DXA). Eighteen women were measured with and without a pair of silicone breast prostheses placed on the upper part of the trunk simulating endogenous implants. Bone area, bone mineral content (BMC), areal bone mineral density (BMD), lean tissue mass (LTM) and fat tissue mass (FTM) of the total body and of the subregions of the body, i.e. the head, trunk, arms and legs, were measured by a Norland XR-36 DXA scanner. After application of the silicone prostheses, bone area, BMC and BMD of the total body significantly increased by an average of 3.7, 6.6 and 3.4% (P<0.0001), respectively. Total body LTM and FTM were not affected. In the trunk region, changes were more pronounced. Trunk BMC, for example, was overestimated by 17.9% (P<0. 0001). The prostheses also influenced measurements of truncal soft tissue composition, with a small but statistically significant overestimation of both LTM (1.1%) and FTM (2.1%) (P<0.05). No changes in bone mass and soft tissue composition were seen in the head, arms and legs. Activation of a high-density detection software utility provided by the manufacturer had no influence on any of the measurements. We conclude that silicone breast prostheses affect the assessment of body composition by DXA.     

Relationship between different subcutaneous adipose tissue layers,fat mass,and leptin in response to short-term energy restriction in obese girls

This study addresses whether the expected relationship of 15 specified subcutaneous adipose tissue layers (SAT layers) from 1-neck to 15-calf and body fat mass (FM) with leptin was influenced by a weight-loss program. In 30 obese girls (10 prepubertal, 15 pubertal, and 5 late/postpubertal) SAT layers were measured by means of the optical device Lipometer. Fat mass (FM) was estimated indirectly by means of bioelectrical impedance. Leptin and insulin were determined by means of radioimmunoassays. All measurements were performed before (pre) and after (post) 3 weeks of low-caloric diet and physical training. At the beginning of the study, there were significant correlations for all estimates of adiposity and leptin (0.67 to 0.79; P < 0.0001). Five SAT layers from the upper body and the trunk (0.48 to 0.67; P < 0.01) but none from the abdominal region and lower extremities were correlated with leptin. FM together with SAT layers 4-upper back and 8-lower abdomen (negative slope) explained 79% of the variation in pre leptin values (P < 0.0001). The weight-loss program significantly reduced leptin (P < 0.0001), insulin (P = 0.04), estimates of adiposity (P < 0.0001), and SAT layers 4-upper back (P = 0.0006), 11-front thigh, 13-rear thigh, and 14-inner thigh (P between <0.03 and <0.01). Although significant, the reductions in the four SAT layers were small. Estimated fat-free mass was significantly increased after three weeks (P < 0.05). Changes in SAT layers from the upper extremities and from the trunk were inversely correlated to the decrease in leptin (P between <0.05 and <0.001). Initial leptin was the best correlate of the decrease in leptin (adj. R² = 0.815; P < 0.0001). However, when only changes in adiposity and insulin were considered in the regression model, changes in insulin contributed to the fall in leptin (adj. R² = 0.23; P = 0.004). When changes in SAT layers were added to the model, changes in SAT layers 2-triceps and 10-hip (negative slopes) contributed to the decrease in leptin (adj. R² = 0.48; P < 0.0001). After weight loss, correlations between estimates of post adiposity and post leptin (0.40, P = 0.01 to 0.57, P = 0.0005) were lower compared with pre values. SAT layers 4-upper back and 3-biceps contributed independently to post leptin values (adj. R² = 0.50; P < 0.0001). It is suggested that fat mass and SAT layers from the upper body are the main determinants of leptin in obese girls before weight loss. The diet and sports intervention program reduced leptin independent of the reduction in adiposity. The distribution of subcutaneous fat might be a stable correlate of circulating leptin after a short-term reduction in energy intake. Am. J. Hum. Biol. 12:803–813, 2000. © 2000 Wiley-Liss, Inc.     

An investigation of ethnic differences in bone mineral, hip axis length, calcium metabolism and bone turnover between West African and Caucasian adults living in the United Kingdom.

The aim of the study was to investigate factors relating to calcium and bone metabolism which might explain the low incidence of osteoporotic fracture among Africans. Adult bone mineral status, hip axis length and biochemical indices were investigated in 20 Caucasians (10 male, 10 female) and 19 Gambians (12 male, 7 female) living in the UK. Bone mineral content (BMC), bone mineral density (BMD) and BMC adjusted for bone area, body weight and height (size-adjusted BMC) were measured for the whole-body, lumbar spine, femoral neck, trochanter, radius shaft and radius wrist using dual-energy X-ray absorptiometry. There were no significant differences in whole body or regional BMC; values tended to be lower in the Gambians. Gambian men had higher size-adjusted BMC at the femoral neck (Gambian-British = 21%, 95% CI = 6 to 36%, p < 0.01), associated with a smaller bone area (Gambian-British = -11%, 95% CI = -20 to -2%, p = 0.02). BMD was affected similarly. No other significant differences in BMD or size-adjusted BMC were observed. Gambians had shorter hip axis length (Gambian British, after accounting for sex, = -5%, 95% CI = -9 to -1%, p = 0.02). There were no significant differences in bone turnover (osteocalcin, bone isoenzyme of alkaline phosphatase, urinary deoxypyridinoline) or calciotropic hormone levels (parathyroid hormone, 1,25-dihydroxyvitamin D, calcitonin). Gambian men had lower 25-hydroxyvitamin D concentrations (Gambian = 26.3 SD 12.0 nmol/L, British = 55.5 SD 13.9 nmol/L, p < 0.0001), a difference not seen among the women. Gambian men and women excreted significantly less phosphate and potassium than British subjects by 30-60%; urinary calcium and sodium excretion were similar in the two groups. This study revealed few ethnic differences that could account for the disparity in osteoporotic fracture rates between Africans and Caucasians, with the possible exception of anatomical differences in the hip.     

Fat mass influence on bone mass is mediated by the independent association between lean mass and bone mass among elderly women: A cross-sectional study

ObjectivesTo study the independent association of fat mass (FM) and lean mass (LM) with bone mass and to study the differences in bone mass by weight and fat status in 223 seniors (aged 65–89 years) from the city of Zaragoza (Spain), after controlling for age, height, physical activity (PA) and LM.Study designCross-sectional study.Main outcome measuresLM, FM, bone mineral content (BMC) and density (BMD) were measured with dual energy X-ray absortiometry. The relationships of FM and LM with bone-related variables (subtotal body, hip, femoral neck and lumbar spine) were analyzed by linear regression and differences between weight and fat status were analyzed by one-way analysis of covariance.ResultsIn men, there were no significant associations between FM and BMC or BMD. In women FM was positively associated with bone-related variables after adjustment for age, height and PA, whereas adjustment for LM removed all these significant associations. Overweight/obese elderly women had higher BMC and BMD than their non-overweight peers in all regions studied. Additional adjustment for PA did not change the differences between weight status groups, while adjusting for LM removed some of the associations. Overfat/obese men and women did not show higher levels of bone mass than their non-overfat peers. LM was positively associated with bone variables in both sexes. Additional adjustment for PA and FM did not alter the results.ConclusionThe association between fat mass and bone mass of elderly women is mediated by the independent association between lean mass and bone mass.     

Lower-limb and whole-body tissue composition assessment in healthy active older women

AIM: The study evaluated, in active elderly women, the accuracy and bias of anthropometry and bioelectrical impedance analysis (BIA) for lower-limb and whole-body tissue composition measures using dual-energy X-ray absorptiometry (DXA) as the criterion method. METHODS: Nineteen individuals (66.1 +/- 4.2 years) participated in the study. Whole-body fat mass (FM) and fat-free mass (FFM) were measured by anthropometry, BIA and DXA. Lower-limb volume (LLV) and lower-limb FFM (LLFFM) were assessed by anthropometry and DXA. RESULTS: LLV and LLFFM were significantly overestimated by anthropometry vs. DXA (p < 0.05 and p < 0.001, respectively) but significant relationships were observed [coefficient of determination (R(2)) > 0.25, p < 0.05]. No significant difference was observed between FM(A) (where (A) stands for anthropometry) vs. FM(DXA) and FFM(A) vs. FFM(DXA) and significant relationships were observed [R(2) = 0.93, p < 0.001, coefficient of variation (CV) = 7.3%; and R(2) = 0.85, p < 0.001, CV = 4.4%, respectively]. No significant difference was observed between FM(BIA) and FM(DXA) and a significant relationship was observed (R(2) = 0.80, p < 0.001, CV = 11.6%). FFM was significantly underestimated by BIA vs. DXA (p < 0.01). CONCLUSIONS: In active elderly women, (i) compared with DXA, anthropometry overestimates LLV and LLFFM; (ii) anthropometry can be an accurate method for assessing whole-body composition; and (iii) despite a non-significant bias for the FM measurement, the BIA tends to overestimate FM and underestimate FFM.     

Sensitivity and specificity of body mass index and skinfold thicknesses in detecting excess adiposity in children aged 8-12 years

Primary objective : The study aimed to evaluate the sensitivity (SN) and specificity (SP) of body mass index (BMI) and skinfold thicknesses in detecting excess adiposity in children. Research design : Cross-sectional. Materials and methods : 986 children (500 females and 486 males) aged 10 &#45 1 years (mean &#45 SD; range: 8-12 years) were studied. All underwent anthropometric measurements and bioelectrical impedance analysis (BIA). Dual-energy X-ray absorptiometry (DXA) was performed in 52 children to develop a population-specific algorithm for the assessment of fat-free mass (FFM) from BIA. The algorithm was applied to the remaining 934 children to estimate their FFM. Fat mass (FM) was obtained by subtracting FFM from weight (Wt). Values of FM:Wt were transformed in Z -scores and converted into 19 percentile categories (from 5 to 95 in steps of 5). The same procedure was performed with BMI and the log-transformed sum of four skinfold thicknesses (triceps, biceps, subscapular and suprailiac; lt-4SF). Excess adiposity was defined as a level of FM:Wt greater than the internally derived 85th percentile. SN and SP of each internally derived percentile of BMI and lt-4SF in detecting excess adiposity were calculated. Results : In the pooled sample ( n = 934), SN and SP were 0.39 and 0.99 for the 95th percentile of BMI, 0.65 and 0.95 for the 85th percentile of BMI, and 0.75 and 0.94 for the 85th percentile of lt-4SF. Conclusions : BMI percentiles employed in the present study have a high SP but a low SN in detecting excess adiposity in 8-12-year-old children. The use of the sum of four skinfolds has the potential to increase the SN of a screening programme for excess adiposity in children of this age.     

Lean body mass and bone mineral density in physically exercising postmenopausal women

OBJECTIVES: To investigate whether the relative contribution of body composition (lean and fat mass component) to postmenopausal bone mineral density (BMD) differs between women participating in physical exercise and sedentary women. METHODS: Subjects were 45 postmenopausal women participating in regular physical exercise and 89 sedentary controls aged 50-60 years. Baseline characteristics included age, height, weight, body mass index (BMI, Wt/Ht(2)), age at menopause, and years since menopause (YSM). Body fat mass, percentage of body fat, lean body mass, and lumbar spine BMD (L2-4) were measured by dual-energy X-ray absorptiometry. RESULTS: Although age, height, weight, BMI, and YSM did not differ between the two groups, lean body mass and lumbar spine BMD were significantly higher (P<0.05 and <0.001, respectively), while body fat mass and percentage of body fat mass were significantly lower in exercising women than in sedentary controls (P<0.05 and <0.05, respectively). In exercising women, BMD was positively correlated with lean body mass (r=0.415, P<0.01) but not with body fat mass (r=0.155, NS). Conversely, in sedentary controls, BMD was correlated with body fat mass (r=0.251, P<0.05) and lean body mass (r=0.228, P<0.05). CONCLUSIONS: Lean body mass is a more significant determinant of postmenopausal BMD in physically exercising women than in sedentary women.     

Nandrolone decanoate treatment of post-menopausal osteoporosis for 2 years and effects of withdrawal

This study investigated the effects of nandrolone decanoate (ND) therapy (50 mg i.m. every 3 or 4 wk) on bone mass and soft tissue body composition in post-menopausal women. Twenty-two (22) women were followed up over a period of 30 mth, during which they received ND therapy for 12–24 mth and were treatment-free for the other 6–18 mth. While they were receiving treatment forearm bone mineral content (BMC) and lean body mass (LBM) increased, whereas fat mass (FM) decreased. After withdrawal of ND therapy the BMC, LBM and FM values all tended to return to pretreatment levels.

Serum high-density-lipoprotein cholesterol showed a non-significant decrease, while serum lowdensity-lipoprotein cholesterol and serum total cholesterol remained unchanged during therapy. It was concluded that ND therapy can achieve an increase in BMC in post-menopausal women, but this is maintained only for as long as therapy is continued.     

Bone mineral density in older non-Hispanic Caucasian and Mexican-American women: relationship to lean and fat mass

PRIMARY OBJECTIVE: The prevalence of osteoporotic fracture is higher in non-Hispanic Caucasian (NHC) than Mexican-American (MA) women in the USA. The present study examined bone mineral density (BMD) in these two ethnic groups and the association between BMD and body composition. RESEARCH DESIGN: Cross-sectional. SUBJECTS: Sixty-two NHC and 54 MA women, aged 60-86 years, with a body mass index (kgm(-2)) of <30. METHODS: BMD (gcm(-2)) of the spine (L2-4), hip (femoral neck, trochanter, Ward's triangle) and whole body was determined by dual-energy X-ray absorptiometry (DXA). Bone mineral-free lean mass (LM) and fat mass (FM) and several ratios of body fat distribution were also assessed by DXA. RESULTS: There was no difference in age (NHC, 69.5+/-0.7; MA 69.5+/-0.9 years; mean +/- SEM) or body mass, but MA women were shorter with a higher truncal adiposity (p < 0.001). There was no significant difference in BMD between groups, however, adjusting for height resulted in higher hip and whole body BMD in MA women (p < 0.01). When volumetric bone density was calculated (bone mineral apparent density; BMAD, gcm(-3)), a trend for higher values in MA women was observed at the femoral neck (p = 0.018). LM contributed independently to BMD at the spine and hip in NHC women, with FM also contributing at the femoral neck. In MA women, LM was an independent contributor to lumbar spine and trochanter BMD, and both LM and FM contributed to whole body BMD. However, the effects of LM and FM were removed in both groups when BMD was adjusted for body or bone size, the only exception being at the trochanter in NHC women. CONCLUSIONS: These results indicate that MA women have higher bone density at the proximal femur than NHC women, which may partially account for their lower rate of hip fracture. Further, differences in bone density between the two ethnic groups do not appear to be dependent on soft-tissue composition.     

Early life and current determinants of bone in South African children of mixed ancestral origin

BACKGROUND: The influence of early life factors on the bone mineral density of children has been identified, however the contribution of these determinants may vary. AIM: The study investigated determinants of bone mineral content (BMC) in South African children of mixed ancestral origin. SUBJECTS AND METHODS: Early life data including birth weight, maternal alcohol consumption and smoking during pregnancy were collected on 9-year-old children of mixed ancestral origin (n = 64). Grip strength was measured, and physical activity, housing density and dietary data were collected. Whole body BMC (WB BMC), fat-free soft tissue and fat tissue were measured using dual energy X-ray absorptiometry. RESULTS: Maternal alcohol consumption during pregnancy was associated with WB BMC, however after adjusting for possible confounders, this was no longer significant. When combined with gender, gestational age and maternal BMC in a multiple regression, maternal alcohol consumption during pregnancy could explain 20% of the variance in the WB BMC, however when current height was included in the model, the contribution of the other factors was insignificant. There was however a significant correlation between current height and birth weight (r = 0.34; p < 0.01) and alcohol consumption during pregnancy (r = 0.34; p < 0.05). A model consisting of current factors such as age, weight, gender, grip strength and calcium intake was able to explain 81.5% of the variance. Housing density was negatively correlated with WB BMC (r =-0.11; p = 0.05). CONCLUSION: These data suggest that although early life factors may contribute indirectly to the bone mass of children of mixed ancestral origin, the contribution of current factors is greater. In addition, environmental factors such as housing density have a direct effect on bone mass, independent of body size.