International journal of body composition research最新文献

Fat distribution, especially increased visceral fat, may be as important as overall obesity in increasing risk of heart disease, type 2 diabetes and certain cancers. Risk of disease, as well as visceral fat, increases dramatically with age. Cross-sectional data suggests that increased risk of disease may be largely prevented if the age related increase in visceral fat does not occur. The objective of this short review is to present data that shows visceral fat increasing over 200% in men and 400% in women between the 3^rd and 7^th decades, show that a combination of weight gain, loss of muscle, and a shift from peripheral to central fat patterning contributes to this increase, and identify hormones that may be responsible for the shift. Finally, the review will show how participation in exercise can slow the age related shift in visceral fat.

A study was conducted to appraise a new EchoMRI™ device for body composition analysis (BCA) of infants and to compare it with dual energy X-ray absorptiometry (DXA), using chemical analysis as a reference method.The calibration part of the study included cross-validation comparisons between EchoMRI™ measurements of awake, anesthetized and dead piglets of the calibration set. It also included comparison of two different approaches to refining the calibration of EchoMRI™, by low- or by high-dimensional linear regressions. Only the low-dimensional approach was applied to DXA.The validation part yielded EchoMRI™ accuracy of 27 g and 70 g for fat and total water, respectively, on piglets scanned while anesthetized, as compared with 24 g and 57 g, respectively, for DXA.EchoMRI™ precision was found to be 4 g and 7 g for fat and total water, respectively, for anesthetized piglets, as compared to 16 g and 14 g, respectively, for DXA. The differences between fat measurements of awake, anesthetized and dead piglets can be statistically significant, but are comparable in magnitude to random errors.To summarize: Characterization of random errors by CV, especially that of fat, is not suitable for BCA, whereas absolute errors or errors relative to total body weight can be applicable. Low- and high-dimensional regressions offer nearly the same accuracy improvements. Improved DXA and EchoMRI™ offer nearly the same accuracy, within 1% of weight in fat, while EchoMRI™ has better precision, within 0.2 % of weight in fat for anesthetized and dead piglets as compared to DXA's 0.5-0.6%.

OBJECTIVE: The purpose of this study was to compare Tanita tetrapolar foot-to-foot bioelectrical impedance analysis (Model TBF-310, Tanita Corporation of America, Inc, Arlington Heights, IL; Tanita-BIA) and fan beam dual-energy X-ray absorptiometry (Hologic Discovery A v12.6, Waltham, MA; DXA) in diabetic patients. METHODS: Seventy Hispanic diabetic participants (23 male, 47 female; mean age: 53.03 ± 10.32 yrs; mean weight: 81.45 ± 17.65 kg; and mean body mass index: 31.40 ± 6.80 kg/m(2)) were selected from the Loma Linda University En Balance culturally-sensitive Spanish diabetes education program using the baseline data. RESULTS: DXA vs Tanita-BIA fat mass (FM), percent fat mass (%FM), and fat-free mass (FFM) were compared using Pearson's (FM: 0.96, %FM: 0.91, and FFM: 0.95), and Spearman's rank (FM: 0.94, %FM: 0.91, and FFM: 0.93) correlation coefficients. Bland-Altman analyses were also used to compare the difference (DXA - BIA) vs average of DXA and BIA results and showed general agreement between the two methods. When Tanita-BIA was regressed onto DXA, the adjusted R(2) was: FM=0.91; %FM=0.83; FFM=0.90. Gender combined concordance correlations with 95% confidence intervals were calculated using a bootstrap re-sampling of the data and found high associations [FM: 0.93 (95% CI: 0.89, 0.96)], [%FM: 0.86 (95% CI: 0.79, 0.90)], and [FFM: 0.93 (95% CI: 0.89, 0.96)]. CONCLUSION: Tanita-BIA may provide valid measures of fat, percent body fat and fat-free mass in Hispanic diabetics, and could be a convenient and practical approach for assessment in community-based research.

Diabetes mellitus continues to be a heavy burden on health and health resources throughout the world. In the USA the burden is borne disproportionately by ethnic minorities such as Hispanics. Therefore health education for Hispanics is important and it can help reduce the incidence of diabetes among Hispanics in the USA.

OBJECTIVE: The objective of this study was to determine associations of anthropometric measures of thigh and abdominal adipose tissue with metabolic risk factors, and whether these associations differed with ethnicity. We hypothesized that thigh circumference (ThC) would have an independent favorable association with insulin sensitivity, lipids, and blood pressure, whereas waist circumference (WC) would have an independent deleterious association with these variables in both African Americans (AA) and European Americans (EA). METHODS: Subjects were 228 healthy, overweight, premenopausal AA and EA women. Insulin sensitivity was assessed by intravenous glucose tolerance test and minimal modeling. Simple relationships between anthropometric measures and risk factors were determined by Pearson correlation analysis. Partial correlation coefficients were determined for circumference measures adjusted for thigh and abdominal skinfolds to differentiate relationships between thigh and abdominal subcutaneous fat from thigh muscle and deeper abdominal fat, respectively. RESULTS: In EA but not AA, ThC was positively associated with insulin sensitivity, independent of thigh skinfold. In both EA and AA, ThC was associated with a desirable lipid profile. In AA but not EA, WC was associated with lower insulin sensitivity and a less desirable metabolic profile. CONCLUSION: Results suggest that thigh muscle (ThC adjusted for thigh skinfold) may be metabolically protective in EA but not AA. In contrast, WC was a better indicator of insulin sensitivity and metabolic health in AA. Further investigation is needed to verify the association between thigh muscle and metabolic health, and to probe the reason for the observed ethnic specificity of the associations between anthropometric measures and metabolic risk factors.

OBJECTIVE: We have previously shown that surrounding fat causes an increase of up to 21% in bone mineral density (BMD) measured by Lunar 'Intelligent DXA' (iDXA), one of the latest generation dual energy X-ray absorptiometry (DXA) scanners [1]. The purpose of our study was to see if it was possible to avoid this artifact when measuring the BMD of metacarpals II, III, and IV by digital X-ray radiogrammetry (DXR). METHODS: We took X-rays of the bones of a cadaveric left hand which were immobilized in a wooden cradle to preserve an approximate in vivo configuration. The X-rays were digitized into Digital Imaging and Communications in Medicine (DICOM) files which were analyzed using dxr-online (dxr-online, Sectra, Sweden) which uses the same DXR-BMD algorithm previously used by Pronosco X-posure v2 and Sectra Osteoporosis package. The X-rays were repeated four times. We then surrounded the bones with a layer of lard, and again X-rayed four times. This process was repeated with the bones were covered by two layers, and then three layers of lard. RESULTS: The measured DXR-BMD increased by a maximum of 0.44% when the metacarpals were covered by either two or three layers of lard compared with when the metacarpals were not covered by lard. CONCLUSION: The measurement of metacarpal BMD measured by DXR is minimally affected by surrounding lard. The measurement of metacarpal BMD by DXR seems to be a way of avoiding the artifactual change in BMD caused by fat, when it is measured by DXA.

OBJECTIVES: Diabetes mellitus and obesity are prevalent in the Hispanic community. This group has not benefited greatly from diabetes interventions due to cultural, language and financial constraints. We designed a prospective cohort study to determine the clinical impact on adiposity and glycemic control in Hispanics with type 2 diabetes. RESEARCH DESIGN AND METHODS: The program conducted in Spanish by a multidisciplinary team of health care providers focused on improving glycemic control and complications through cultural lifestyle changes. Outcomes were changes in glycemic control by fasting insulin, glucose and HbA1c, body composition and selected adipokines, adiponectin, leptin and ghrelin. Body composition was measured by dual energy x-ray absorptiometry. Changes from baseline at three months were compared using paired t-tests and with Spearman's correlations. RESULTS: Glycemic control improved by HbA1c (7.9% ± 2.0% vs 7.1% ± 1.7%; P = <0.001), and fasting glucose (166.4 ± 66.0 mg/dl vs 143.2 ± 57.9 mg/dl; P = 0.003). Body weight (81.3 ± 17.9 kg vs 80.3 ± 18.0 kg; P = 0.002), waist circumference (101.6 ± 13.4 cm vs 99.1 ± 12.7 cm; P = 0.015), and truncal fat (16.5 ± 5.7 kg vs 15.9 ± 5.6 kg; P = 0.001) decreased. Only leptin (19.6 ± 15.0 ng/ml vs 16.3 ± 12.7 ng/ml; P = 0.002) was reduced and related to change in body weight (r = 0.392; P = 0.022). CONCLUSIONS: Our program significantly improved glycemic control and decreased obesity in diabetic Hispanic subjects. The early benefits on glycemic control may be related to reductions in leptin through loss of adipose tissue. Success in impacting diabetes and related complications can occur in a culturally focused and multidisciplinary context.

OBJECTIVE: To assess the effects of a language-sensitive diabetes education program on dietary changes and plasma lipid profiles. METHOD: Hispanic participants (n=13 males and 18 females, mean age = 54.00 + 10.68 years) participated in a 3-month health education study. Spearman correlation coefficients were used to evaluate correlations between dietary intake and laboratory measurements. RESULTS: There were significant decreases in serum total cholesterol (-16.07 mg/dl, P= 0.035), HDL cholesterol (-3.23 mg/dl, P = 0.01), LDL cholesterol (-11.71 mg/dl, P = 0.013) and dietary cholesterol (-79.22 mg, P = 0.03). No significant mean change was observed in triglyceride and total cholesterol/HDL ratio. There was also a reduction in body mass index (BMI) (-0.15 kg/m(2), P = 0.40), fasting glucose (-3.90 mg/dl, P = 0.43) and dual energy X-ray absorptiometry (DXA) total fat (-0.50, P = 0.97). Although not statistically significant, saturated fatty acids (-4.90 g, P = 0.19), polyunsaturated fatty acids (-3.31g, P = 0.11), and carbohydrate (-44.82 g, P = 0.22), decreased after three months. CONCLUSION: There were significant improvements in dietary intake and serum lipids after a three-month culture-specific diabetes education program.

OBJECTIVE: To validate the use of quantitative magnetic resonance (QMR) to measure fat and lean mass in conscious rats. METHODS: Fifty Osborne-Mendel rats (249-770 g) were scanned using the Echo Medical 2 MHz body composition analyzer. Each rat was scanned under six settings (three acquisition times, with and without determination of total water). Precision was determined by the calculated coefficient of variation (CV) of three consecutive scans. Accuracy was determined by comparing the first scan to chemical carcass analysis and analyzed by paired t-tests and least-squares regression analyses. Twenty-five rats were used in the validation study, and 25 in the cross-validation study. RESULTS: The precision for fat, lean and water at all settings was <1%. QMR significantly overestimated fat (~5%; P<0.0001), and underestimated both lean (~12.5%; P<0.0001) and total water (~5.5%; P<0.0001). All QMR measures were significantly correlated with carcass measures (r(2)>0.99; P<0.0001). Using prediction equations from the validation study with the cross-validation rats, there were no significant differences between QMR fat and carcass fat at any setting (P>0.400). For four of the six QMR settings, there were no significant differences between QMR and carcass lean (P>0.05). For total water, all QMR settings were significantly different than carcass (P<0.05), but only by ~1%. CONCLUSIONS: QMR showed excellent precision for the determination of fat, lean and water. Despite overestimating fat and underestimating lean and water, all were highly related to carcass values. When tested in the cross-validation group, QMR fat could be accurately predicted at all settings; however, lean mass (two settings) and water were still slightly different (less than 1%).