Improvements in the management of rheumatic patients from vertebral image obtained through dual-energy X-ray absorptiometry

The diagnosis of asymptomatic vertebral fracture is clinically useful and the identification of new fractures may influences the choice of appropriate therapeutic measures. In order to identify moderate and asymptomatic vertebral deformities in an objective and reproducible manner, vertebral morphometry is performed. This method measures the vertebral body's anterior, middle and posterior heights at the dorsal and lumbar level. Currently this technique is performed on lateral images of the spine obtained through the traditional X-ray method (radiological morphometry or morphometric X-ray radiography, MRX) and, more recently from images obtained through dual-energy X-ray absorptiometry (DXA) machines (visual assessment of X-ray absorptiometry scans or morphometric X-ray absorptiometry, MXA), commonly used to measure bone mineral density. The main advantage of MXA relative to MRX is the lower radiation dose to which the patient is exposed during the exam. In addition, MXA scans offers the advantage of acquiring a single image of thoracic and lumbar spine, without any distortion (e.g.: coning). The most obvious advantage of MXA is the opportunity of obtaining during the same session a bone mineral density evaluation, and digital images that are easily processable, manageable, recordable and comparable for the patient's follow up. A limitation of the MXA technique is the inferior quality of the images, that make often impossible the detection of the vertebral edges, and the impossibility to visualize the upper thoracic vertebral bodies. MXA, despite its intrinsic limitations, when carried out by trained personnel may provide substantial improvements in the management (diagnosis and follow-up) of rheumatic patients.     

Body composition analysis by leg-to-leg bioelectrical impedance and dual-energy X-ray absorptiometry in non-obese and obese individuals

Aim: The aim of this study is to compare total weight, % body fat (% BF), fat mass (FM) and fat‐free mass (FFM) measured by bioelectrical impedance analysis (BIA) and dual‐energy X–ray absorptiometry (DXA). Methods: This cross‐sectional study included 159 women (mean age: 49.1 ± 10.0 years) and 124 men (mean age: 51.4 ± 8.0 years) subdivided according to sex and body mass index (BMI): BMI < 30 kg/m² (66 women and 50 men); BMI 30–35 kg/m² (53 women and 44 men) and BMI ≥ 35 kg/m² (40 women and 30 men). Bioelectrical impedance was performed in the fasting state on a Tanita TBF‐215 leg‐to‐leg analyser (Tanita, Tokyo, Japan). Whole‐body DXA scans were performed on a Hologic QDR 4500 A bone densitometer (Hologic, Bedford, MA, USA). Total weight, % BF, FM and FFM were tested for intermethod differences. Linear regression and correlation analysis was performed. Limits of agreement and Bland–Altman plots were built. Results: DXA‐derived body composition parameters were not significantly different from BIA estimates and were highly correlated (e.g. for FFM, r = 0.82–0.95). In lean individuals, BIA tended to produce lower values for FM and % BF and higher ones for FFM in comparison with DXA. This trend was reversed at BMI > 35 kg/m². The correlations decreased with increasing BMI. The limits of agreement were much better in men than in women and increased with increasing BMI in both sexes. Conclusions: Compared with DXA, the leg‐to‐leg Tanita TBF‐215 analyser accurately assessed body composition in a heterogeneous group of both sexes. In the very obese women (BMI > 35 kg/m²), BIA measurements should be viewed with caution.     

Measurement of abdominal fat by magnetic resonance imaging, dual-energy X-ray absorptiometry and anthropometry in non-obese men and women.

OBJECTIVE: To investigate whether the dual-energy X-ray absorptiometry (DEXA) was a better predictor of abdominal fat, measured by magnetic resonance imaging (MRI) at the level of L2-L3, than anthropometric measurements in non-obese men and non-obese women. DESIGN: Observational, cross sectional study. SUBJECTS: 34 healthy subjects (17 men and 17 women) aged 20-53 y with a body mass index (BMI) < 30 kg/m2. MEASUREMENTS: Fat distribution parameters including waist circumference and waist-to-hip ratio (WHR); intra abdominal fat (IAF) by MRI; and central abdominal fat (CAF) by DEXA. RESULTS: Measurement of IAF by MRI, was highly correlated to the CAF measured by DEXA. In men, both waist circumference and WHR had similar correlation to IAF as DEXA. In women, waist circumference was less well correlated with IAF than DEXA, and the WHR had a weaker non significant correlation with IAF. CONCLUSIONS: In non-obese men; DEXA, waist circumference and WHR can predict IAF equally well, while in non-obese women, DEXA is superior to waist circumference and much better than WHR.     

The prediction of visceral fat by dual-energy X-ray absorptiometry in the elderly: a comparison with computed tomography and anthropometry

INTRODUCTION: Effective methods for assessing visceral fat are important to investigate the role of visceral fat for the increased health risks in obesity. Techniques for direct measurement of soft tissue composition such as CT or MRI are expensive, time-consuming or require a relatively high radiation dose. Simple anthropometric methods, such as waist-to-hip ratio, waist circumference or sagittal diameter are widely used. However, these methods cannot differentiate between visceral and subcutaneous fat and are less accurate. The aim of the present study is to investigate whether the dual-energy X-ray absorptiometry (DXA) method, possibly combined with anthropometry, offers a good alternative to CT for the prediction of visceral fat in the elderly. METHODS: Subjects were participants in the Health ABC-study, a cohort study of black and white men and women aged 70-79, investigating the effect of weight-related health conditions on disablement. Total body fat and trunk fat were measured by DXA using a Hologic QDR 1500. A 10 mm CT scan at the L4-L5 level was acquired to measure visceral fat and total abdominal fat. Weight, height, sagittal diameter and waist circumference were measured using standard methods. Fat in a manually defined DXA subregion (4 cm slice at the top of iliac crest) at the abdomen was calculated in a sub-group of participants (n=150; 50% male; 45.3% Afro-American/54.7% Caucasian, age 70-79 y). This subregion, the standard trunk region and total fat were used as indicators of visceral fat. RESULTS: Total abdominal fat by DXA (subregion) was strongly correlated with total abdominal fat by CT (r ranging from 0.87 in white men to 0.98 in black women). The DXA subregion underestimated total abdominal fat by 10% compared to the CT slice. The underestimation by DXA was seen especially in people with less abdominal fat. The association of visceral fat by CT with the DXA subregion (r=0.66, 0.78, 0.79 and 0.65 for white and black men and women, respectively) was comparable with the association of the CT measure with the sagittal diameter (r=0.74, 0.70, 0.84 and 0.68). Combining DXA measurements with anthropometry gave only limited improvement for the prediction of visceral fat by CT compared to univariate models (maximal increase of r(2) 4%). CONCLUSION: DXA is a good alternative to CT for predicting total abdominal fat in an elderly population. For the prediction of visceral fat the sagittal diameter, which has a practical advantage compared to DXA, is just as effective.     

Long-term performance in vitro and in vivo of dual-energy X-ray absorptiometry

Summary Dual-energy X-ray absorptiometry (DXA) is actually considered as one of the most appropriate techniques for measuring bone mineral content (BMC) and bone mineral density (BMD). An anthropomorphic phantom and a 25-yearold girl were repeatedly measured, 160 times and 50 times respectively, over an 18-month period to investigate performance in vitro and in vivo of a commercial DXA equipment (HOLOGIC QDR 1000). DXA is a highly accurate technique, the BMC and BMD determinations only overestimated the exact value of the phantom by 0.20% and 0.51% respectively. In vivo long-term (18 months) reproducibility of BMD of the spine is characterized by an interassay coefficient of variation (CVt) of 0.8% while, for the different regions of interest of the hip, BMD CVt varies from 1.1% (total zone) to 5.3% (Ward's triangle). In the subject tested, BMD sensitivity for changes of 2.2% at the lumbar spine and 3% at the hip were recorded.     

Weight cycling and cardiovascular risk factors in obesity

OBJECTIVE: To assess the relationship between weight cycling and some cardiovascular risk factors in a wide sample of obese subjects. DESIGN: Cross-sectional study with retrospective evaluation of weight and dieting history. SUBJECTS: In all, 459 obese subjects, 340 women and 119 men (age: 19-65 y; BMI: 30-69 kg/m2). MEASUREMENTS: Body composition and fat distribution (by bioelectrical impedance analysis and anthropometry), systolic and diastolic blood pressure, plasma glucose, total and HDL cholesterol, triglycerides, insulin and insulin resistance by HOMAir, various weight cycling indices. RESULTS: A positive correlation between weight cycling indices, BMI and percent body fat was found in both genders. Also, the maximum absolute amount of weight regained following a single diet episode was significantly associated to insulin and HOMAir in both genders. However, these correlations disappeared when the data were controlled for age and BMI. CONCLUSION: In obese subjects of both genders weight cycling, and in particular weight regain, does not appear to be associated with adverse effects on body composition, fat distribution or cardiovascular risk factors in an independent manner, but rather in relation to fat accumulation over years.     

Obesity indices and cardiovascular risk factors in Thai adults

OBJECTIVE: To examine the relationship of body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHpR) and waist-to-height ratio (WHtR) with cardiovascular risk factors and diabetes in Thai population. DESIGN: A national cross-sectional survey of cardiovascular risk factors. SUBJECTS: Five thousand and three hundred five Thai adults aged > or =35 years. MEASUREMENTS: Body weight, height, waist and hip circumference and cardiovascular risk factors including blood pressure, total plasma cholesterol, high-density lipoprotein, triglyceride and fasting plasma glucose were measured. Age- and sex-specific means and prevalence of cardiovascular risk factors were calculated and compared among anthropometric measurements. RESULTS: There were increasing trends of severity of cardiovascular risk factors and prevalence of morbidity conditions across increasing levels of BMI, WC, WHpR and WHtR categories. For age group > or =65 years, WC, WHpR and WHtR provided more consistent association with cardiovascular risk factors than BMI. Area under the curve indicated that measurement of central obesity could predict cardiovascular risk better than BMI. The optimal cutoff points for anthropometric measurements were in line with the Asia-Pacific recommendation; however, similar cutoff point for men and women between 82 and 85 cm was observed. CONCLUSION: Central obesity indices were slightly better associated with cardiovascular risk factors compared to BMI in Thai adults aged > or =35 years.     

Four anthropometric indices and cardiovascular risk factors in Taiwan

OBJECTIVE: To examine the relationships between four anthropometric measurements and cardiovascular risk factors in Taiwan. DESIGN: The data was collected from four nationwide health screen centers in Taiwan from 1998 to 1999. SUBJECTS: A total of 38 556 subjects: 18 280 men and 20 276 women, mean age=37.0+/-11.1 y. None had any known major systemic diseases or were currently on medication. MEASUREMENTS: Individual body weight, height, waist circumference (WC), and cardiovascular risk factors (blood pressure, fasting plasma glucose, triglycerides, total cholesterol level, low-density and high-density-lipoprotein cholesterol level) were assessed and their relationships were examined. RESULTS: In both sexes, with increasing body mass index (BMI), WC, WHpR (waist-to-hip ratio) and WHtR (waist-to-height ratio), there were significantly higher risks of hypertension, impaired fasting glucose, diabetes and dyslipidemia (P<0.001) in almost all age groups. In the age groups older than 65, however, the relationships were statistically inconsistent. CONCLUSIONS: In Taiwan, the four anthropometric indexes (BMI, WC, WHpR, WHtR) are closely related to cardiovascular risk factors.     

Comparison of body fatness measurements by BMI and skinfolds vs dual energy X-ray absorptiometry and their relation to cardiovascular risk factors in adolescents

OBJECTIVE: To compare estimates of adiposity by dual emission X-ray absorptiometry (DXA), skinfolds and body mass index (BMI); and to evaluate the relation of these measures to cardiovascular risk in adolescents. DESIGN: In a cohort of adolescents participating in a longitudinal study of insulin resistance, Slaughter formulas were used to estimate adiposity from skinfolds and DXA was used to estimate adiposity as % body fat (%BF) and fat mass (FBM). BMI, blood pressure, lipids and insulin resistance were measured. SUBJECTS: Male and female, 11-17 y old (n=130). MEASUREMENTS: To compare DXA with two office-based methods of assessing fatness and cardiovascular risk. RESULTS: Slaughter estimates were highly correlated with DXA (%BF r=0.92, P=0.0001; FBM r=0.96, P=0.0001). Correlations were similar in heavy and thin children. BMI was also highly correlated with DXA (%BF r=0.85, P=0.0001; FBM r=0.95, P=0.0001), and these relations were stronger in heavy than thin children. BMI and the Slaughter formulas were similar to DXA in their relations to cardiovascular risk factors. CONCLUSIONS: Adiposity by BMI and Slaughter formulas are highly correlated with DXA and similarly related to cardiovascular risk factors. BMI is easy to obtain and is an acceptable method for initial office estimation of body fatness. BMI and skinfolds compare well with DXA in predicting adverse cardiovascular risk profile.     

Body composition profiles derived from dual-energy X-ray absorptiometry, total body scan, and mortality

Little has been reported on the association of derived body composition data and cardiovascular mortality. The authors defined body composition profiles based on one- and two-variable measures from dual-energy x-ray absorptiometry (DXA) total body scans. Scan results are labeled "apple" if Z score for percent of total fat in trunk is >0 and "pear" if Z score for height-corrected limb fat is > or = 0. The fat measures were combined to define four body composition profiles: "pickle," "avocado," "mango," and "barrel." A third axis, the Z score of height-corrected limb lean tissue, is an index of skeletal muscle mass and was used to label subjects as "hard" or "soft." Subjects (n=324) who were in good health from Malm?, Sweden, underwent body composition analysis using DXA and were followed for 10 years. The distribution of body composition profiles was similar for both genders and across age groups. Among subjects aged 50-74 years at baseline (n=116), there were 21 deaths. Barrel had the highest mortality rate: 13/39 (33.3%) mortality for barrels, compared with 8/77 (10.4%) mortality for non-barrels; mortality odds ratio, 3.2; 95% confidence interval, 1.45-7.08. The increased mortality was principally attributable to cardiovascular cause-related deaths. Soft (sarcopenia) was also associated with increased mortality (25.9%; p=0.05), but not cardiovascular cause-related deaths, whereas the total mortality among apples was not significantly increased but cardiovascular cause-related deaths were predominant (75%; p=0.02). The authors propose that DXA-body composition profiles can identify increased mortality risk of magnitude similar to major cardiovascular risk factors and may prove useful in health assessment.     

Optimal cut-off values for obesity: using simple anthropometric indices to predict cardiovascular risk factors in Taiwan

BACKGROUND: The increased health risks associated with obesity have been found to occur in Asians at lower body mass indices (BMIs). To determine the optimal cut-off values for overweight or obesity in Taiwan, we examined the relationships between four anthropometric indices and cardiovascular risk factors. METHODS: The data were collected from four health-screening centers from 1998 to 2000 in Taiwan. Included were 55 563 subjects (26 359 men and 29 204 women, mean age=37.3+/-10.9 and 37.0+/-11.1 y, respectively). None had known major systemic diseases or were taking medication. Individual body weight, height, waist circumference (WC), and a series of tests related to cardiovascular risk (blood pressure, fasting plasma glucose, triglycerides, total cholesterol, low- and high-density lipoprotein cholesterol) were assessed and their relationships were examined. Receiver operating characteristic (ROC) analysis was used to find out the optimal cut-off values of various anthropometric indices to predict hypertension, diabetes mellitus and dyslipidemia. RESULTS: Of the four anthropometric indices we studied, waist-to-height ratio (WHtR) in women was found to have the largest areas under the ROC curve (women=0.755, 95% CI 0.748-0.763) relative to at least one risk factor (ie hypertension or diabetes or dyslipidemia). The optimal cut-off values for overweight or obesity from our study in men and women showed that BMIs of 23.6 and 22.1 kg/m(2), WCs of 80.5 and 71.5 cm, waist-to-hip ratios (WHpR) of 0.85 and 0.76, and WHtR of 0.48 and 0.45, respectively, may be more appropriate in Taiwan. CONCLUSIONS: WHtR may be a better indicator for screening overweight- or obesity-related CVD risk factors than the other three indexes (BMI, WC and WHpR) in Taiwan. Our study also supported the hypothesis that the cut-off values using BMI and WC to define obesity should be much lower in Taiwan than in Western countries.     

Body composition and bone mineralization measurement in calves of different genetic origin by using dual-energy X-ray absorptiometry

The purpose of this study was to investigate the differences in bone mineralization [bone mineral density (BMD, g/cm(2)), and bone mineral content (BMC, %)] and body composition of F1 and F2 crossbred calves and their purebred controls from the dairy breeds German Holsteins (GH) and German Fleckvieh (FV). In total, 62 male and 64 female calves were analyzed under light sedation with dual-energy X-ray absorptiometry (DXA). The study started when the calves were 4 days old and continued until they were 60 days old. GH calves had a significantly lower BMD than all other lines-with the highest BMD and BMC in the FV male symbol x F1 female symbol line. Since the average BMD of the F1 calves was higher than the average BMD of their parents, a small heterosis effect for this trait seems likely. The absolute differences in soft tissue composition were small with a slightly higher average fat content for F1 calves compared with the parent breeds.     

Clustering of cardiovascular risk factors in confirmed prehypertensive individuals.

Numerous studies have indicated that hypertensive subjects have an atherogenic lipoprotein pattern, hyperinsulinemia, and impaired glucose tolerance relative to normotensive individuals. These abnormalities could be due to adverse effects of certain antihypertensive agents, to pathophysiological concomitants of the hypertensive state itself, or to both. In this report, we describe the cardiovascular risk factor profile of 1,440 subjects who were normotensive and were not taking any antihypertensive medications when first examined and who subsequently participated in the 8-year follow-up of the San Antonio Heart Study. Hypertension developed in 130 subjects during the follow-up period. At baseline these prehypertensive individuals had significantly higher levels of blood pressure, fasting total and low density lipoprotein cholesterol, triglyceride, glucose, and insulin, and 2-hour glucose than those who remained free of hypertension. In addition, they had higher body mass indexes, a less favorable body fat distribution, and lower levels of high density lipoprotein cholesterol. In multiple linear regression analyses, baseline levels of triglyceride and blood pressure remained significantly higher and high density lipoprotein cholesterol remained significantly lower in the subjects who later converted to hypertension than in those who remained normotensive. Although baseline insulin levels were also higher in the prehypertensive subjects, this difference was not statistically significant. In nonobese subjects, however, those with high baseline insulin concentrations had an increased incidence of hypertension compared with those with low insulin concentrations. The present results suggest that the cluster of atherogenic changes associated with hypertension actually precede the development of the hypertensive state.     

Association between simple anthropometric indices and cardiovascular risk factors.

OBJECTIVE: To identify which of the three simple anthropometric indices, body mass index (BMI), waist-to-hip ratio (WHR) and waist circumference (WC), best predicts cardiovascular risk factors, and to determine if the association between the anthropometric indices and cardiovascular risk factors varies with gender. DESIGN AND METHODOLOGY: A cross-sectional population-based survey was carried out during 1995-1996. One thousand and ten Chinese people (500 men and 510 women) aged 25-74 y were recruited as subjects for the study. Metabolic profiles and anthropometric indices were measured. RESULTS: Partial correlation and co-variance analyses showed that WC exhibited the highest degree of association with almost all of the studied metabolic profiles for both men and women. We observed significant gender differences in the association between central or general obesity with cardiovascular risk factors. BMI had an independent and significant association with metabolic risks in men, but not in women, whereas WHR was more strongly correlated with metabolic risks for women than for men. Logistic regression analysis further confirmed the magnitude of the association between the obesity indices and metabolic risks. Among the studied metabolic variables, serum insulin showed the highest degree of association with the obesity indices, followed by plasma glucose, triglyceride, HDL and blood pressure. Total cholesterol and LDL-cholesterol had a small but significant correlation with obesity. No threshold values in the relation between either the anthropometric indices and metabolic values, or with hypertension, diabetes and dislipidemia were observed. CONCLUSION: The association of central or general obesity and metabolic syndrome varied with gender. In addition, the useful anthropometric predictors for cardiovascular risk factors were BMI and WC for men, and WC and WHR for women.     

Osteopenia in primary biliary cirrhosis and cirrhosis of the liver in women,evaluated by dual-energy X-ray absorptiometry

To study bone involvement in primary biliary cirrhosis (PBC), we used dual-energy X-ray absorptiometry to measure bone mineral density (BMD) in Japanese women with PBC and with cirhosis of the liver. In both groups, in each decade up to 60 years of age, the mean BMD of the lumbar spine was not significantly different from that in healthy Japanese women; however, in patients aged 60 years or more, the level was significantly lower both in the patients with PBC (P<0.001) and in those with cirrhosis of the liver (P<0.01). Patients with PBC were also examined by single-photon absorptiometry. The BMD of the radius in the patients with PBC was less changed than that of the lumbar vertebrae; thus, the bone changes in PBC seem to be greater in spongy than in cortical bone.     

Assessment of limb muscle and adipose tissue by dual-energy X-ray absorptiometry using magnetic resonance imaging for comparison

OBJECTIVE: To use magnetic resonance imaging (MRI) to validate estimates of muscle and adipose tissue (AT) in lower limb sections obtained by dual-energy X-ray absorptiometry (DXA) modelling. DESIGN: MRI measurements were used as reference for validating limb muscle and AT estimates obtained by DXA models that assume fat-free soft tissue (FFST) comprised mainly muscle: model A accounted for bone hydration only; model B also applied constants for FFST in bone and skin and fat in muscle and AT; model C was as model B but allowing for variable fat in muscle and AT. SUBJECTS: Healthy men (n = 8) and women (n = 8), ages 41-62y; mean (s.d.) body mass indices (BMIs) of 28.6 (5.4) kg/m2 and 25.1 (5.4) kg/m2, respectively. MEASUREMENTS: MRI scans of the legs and whole body DXA scans were analysed for muscle and AT content of thigh (20 cm) and lower leg (10 cm) sections; 24h creatinine excretion was measured. RESULTS: Model A overestimated thigh muscle volume (MRI mean, 2.3 l) substantially (bias 0.36 l), whereas model B underestimated it by only 2% (bias 0.045 l). Lower leg muscle (MRI mean, 0.6 l) was better predicted using model A (bias 0.04 l, 7% overestimate) than model B (bias 0.1 l, 17% underestimate). The 95% limits of agreement were high for these models (thigh, +/-20%; lower leg, +/-47%). Model C predictions were more discrepant than those of model B. There was generally less agreement between MRI and all DXA models for AT. Measurement variability was generally less for DXA measurements of FFST (coefficient of variation 0.7-1.8%) and fat (0.8-3.3%) than model B estimates of muscle (0.5-2.6%) and AT (3.3-6.8%), respectively. Despite strong relationships between them, muscle mass was overestimated by creatinine excretion with highly variable predictability. CONCLUSION: This study has shown the value of DXA models for assessment of muscle and AT in leg sections, but suggests the need to re-evaluate some of the assumptions upon which they are based.     

Truncal fat determined by dual-energy X-ray absorptiometry is an independent predictor of coronary artery disease extension

BACKGROUND: Controversy prevails regarding the existence of a correlation between the severity of coronary artery disease (CAD) and the extent and distribution of obesity. PURPOSE: To assess the correlation between total fat, truncal fat (TF), and lean mass, obtained with dual-energy X-ray absorptiometry (DEXA) and standard anthropomorphic indices (body mass index, waist circumference, waist-to-hip ratio) and to verify whether DEXA indices can predict the extent and severity of CAD. MATERIALS AND METHODS: Fifty-eight patients (19 females) consecutively referred for coronary angiography underwent physical examination and DEXA assessment of body composition. RESULTS: Of the 58 patients enrolled, 22 were overweight and 13 were obese. Significant CAD was found in 39 (67%) patients. DEXA-derived total mass and fat mass enabled us to distinguish overweight from obese patients (P<0.005), whereas just TF mass correlated with the number of diseased vessels after adjusting for body mass index, sex, age, and smoking habit (odds ratio, 8.68; 95% confidence interval: 1.02-74.10). CONCLUSION: TF determined by DEXA is independently related with CAD extension.     

Acute exercise improves postprandial cardiovascular risk factors in overweight and obese individuals

ObjectivesThe effects of 30 min of exercise on postprandial lipaemia in the overweight and obese are unknown as previous studies have only investigated bouts of at least 60 min in lean, healthy individuals. The aim of this study was to investigate whether a single 30-min bout of resistance, aerobic or combined exercise at moderate-intensity would decrease postprandial lipaemia, glucose and insulin levels as well as increase resting energy expenditure and increase fat oxidation following a high fat meal consumed 14 h after the exercise bout, in overweight and obese individuals compared to no exercise. We also compared the effects of the different exercise modalities.MethodsThis study was a randomized cross-over design which examined the postprandial effects of 30 min of different types of exercise in the evening prior to a breakfast meal in overweight and obese men and women. Participants were randomized on four occasions, each one-week apart, to each condition; either no exercise, aerobic exercise, resistance exercise or a combination of aerobic exercise and resistance exercise.ResultsAn acute bout of combination training did not have any significant effect on postprandial measurements compared to no exercise. However, aerobic exercise significantly reduced postprandial triglyceride levels by 8% compared to no exercise (p = 0.02) and resistance exercise decreased postprandial insulin levels by 30% compared to aerobic exercise (p = 0.01).ConclusionThese results indicate that a single moderate-intensity 30 min bout of aerobic or resistance exercise improves risk factors associated with cardiovascular disease in overweight and obese individuals.     

The role of obesity in the association of cardiovascular risk factors and glucose intolerance in small Japanese and North American communities

To investigate whether the influence of obesity on cardiovascular risk factors and glucose intolerance differs between Japan and the US, we conducted cross-sectional surveys in those with elevated plasma glucose in Tanushimaru, Japan, and a stratified random population sample, in Wadena, MN. Subjects numbered 204 in Tanushimaru and 334 in Wadena. Body mass index (BMI), blood pressure, blood lipids, fasting plasma levels of glucose, glycosylated hemoglobin A(1c,) insulin, and free fatty acids were assessed. Overweight was defined as BMI of 27.5-29.9 kg/m(2) and obesity as BMI> or =30 kg/m(2). Gradual increases in risk factors were seen as BMI increased in both studies. Most risk factors were associated with glucose intolerance, except for BMI in Tanushimaru. In Wadena, glucose intolerance increased sharply among the obese. Adjustment for BMI attenuated the associations of cardiovascular risk factors with glucose intolerance in Wadena, but not in Tanushimaru. Obesity has an exaggerated influence on risk factors, compared with being overweight. The associations of glucose intolerance with cardiovascular risk factors are more affected by adjustment for BMI in Wadena than in Tanushimaru, not because of a different influence of body weight on risk factors between the two cities, but because obesity is rare in Japan.