Test-retest reliability of air displacement plethysmography (BOD POD) in the adult healthy Indian male population

Objectives: Several studies have shown that air displacement plethysmography (ADP) has excellent reliability, accuracy and precision in body fat percentage (BF%) measurement, but its reliability has not been assessed in the Indian population. Thus, this study aimed to determine the test-retest reliability of BF% by ADP in healthy Indian men. Materials and Methods: A total of 74 healthy Indian men (>18 years old) belonging to different parts of India voluntarily participated in the study and completed multiple trials to determine BF% immediately after the initial measurements. All tests were performed according to the manufacturer’s instructions. Results: A paired t-test showed no significant differences in body volume (BV) (P = 0.53), body density (BD) (P = 0.39) and BF% (P = 0.27) between trials 1 and 2. However, there was a significant decrease in body mass (BM) observed between trials 1 and 2 (P = 0.0001) which did not influence reliability. A significant intraclass correlation was observed for BM (intraclass correlation 1 [ICC1] = 1, P <0.001), BV (ICC1 = 1, P < 0.001), BD (ICC1 = 0.996, P < 0.001) and BF% (ICC1 = 0.995, P < 0.001) between the initial test and retest trial. The third assessment of BF% was performed when the initial trial difference was greater than 1% point. Significant intraclass correlations were also observed for pairs with maximum and minimum differences. Conclusion: ADP appears to be a reliable measure for determining the BF% of the Indian adult male population, and conducting multiple trials are necessary to detect small differences.

Major risk factors for obstructive sleep apnea monitored in the home. A cross-sectional study

ABSTRACT BACKGROUND: Obstructive sleep apnea (OSA) is characterized by recurrent pharyngeal wall collapse during sleep caused by anatomical or functional changes associated with obesity or dislocation of maxillofacial structures. OBJECTIVE: To determine the major risk factors for obstructive sleep apnea monitored in the home. DESIGN AND SETTING: Cross-sectional study conducted in a private clinic in Fortaleza (CE), Brazil. METHODS: Between 2015 and 2018, 427 patients were screened for OSA with home-based monitoring, yielding 374 positives. Information was collected on age, sex, body mass index (BMI), hypertension, diabetes (DM), dyslipidemia, coronary artery disease (CAD), arrhythmia, peripheral artery occlusive disease (PAOD), heart failure (HF) and lung disease. The home sleep apnea test result was then compared with the clinical diagnosis. Lastly, parameters identified as significant in the univariate analysis were subjected to multivariate logistic regression. RESULTS: Male sex predominated, although not significantly. OSA was associated with hypertension, DM, dyslipidemia, age and BMI. The risk of OSA being associated with these parameters was 2.195 (hypertension), 11.14 (DM), 2.044 (dyslipidemia) and 5.71 (BMI). The association was also significant for BMI categories (normal, overweight or obese). No significant association was observed for CAD, arrhythmia, PAOD, HF or lung disease. After multivariate logistic analysis, only age and BMI (and its categories) remained significant. CONCLUSION: OSA was associated with hypertension, DM, dyslipidemia, age and BMI in univariate analyses, but only with age and BMI (and its categories) in multivariate logistic analysis.

Differences in body density and percent body fat found by different methods of evaluating body composition / 体力科学

<p>The objectives of this study were 1) to quantify the differences in body densities and percent body fat using various methods for evaluating body composition (e.g., underwater weighing (UWW), air displacement plethysmography (ADP), skinfold caliper (SKF) measurement, ultrasound (US), bioelectrical impedance analysis (BIA), and dual-energy x-ray absorptiometry (DXA)), and 2) to examine the relationship between trends of the differences in body density and percent body fat obtained by these methods and characteristics of morphology and body composition. To this end, the body compositions of 73 healthy male adults were measured using UWW, ADP, SKF, US, and BIA. Twenty-seven of these 73 subjects underwent further measurement using DXA. Differences in body densities determined with ADP, SKF, and US were compared with those measured using UWW as a reference, and the differences in percent body fat estimated with UWW, ADP, SKF, US and BIA were compared with those measured by DXA as a reference. The results of this study indicate that 1) ADP is useful as a method for evaluating body density, as the results differed insignificantly from the reference method and showed no systematic errors due to differences in morphological characteristics and body composition, and 2) UWW measurements exhibited the smallest difference in percent body fat from the reference method, however, more than in any other method, there were systematic errors due to differences in morphological characteristics and body composition, specifically, trunk composition.</p>

Effects of bone mineral content and density on accuracy of body fat measurement by underwater weighing / 体力科学

Underwater weighing is based on the assumption that fat-free body density is roughly constant among humans. This assumption should be examined, because fat-free body density may in fact depend on the bone mineral and water contents of the body, with fat excluded. The purpose of this study was to investigate the effects of bone mineral content (BMC) and density (BMD) on the accuracy of body fat measured underwater. The subjects were 12 young men (25.1±3.7 years, mean ± SD), some of whom were trained athletes. BMC and BMD were measured by dual-energy x-ray absorptiometry (DXA), as was body fat, as a percentage of body weight; this method is not based on the assumption that fat-free body density is the same in different individual. Body fat as a percen tage of body weight was measured underwater, also. Body fat measured by DXA was significantly correlated with that found by underwater weighing (r = 0.83, p<0.01), as expected, but the mean body fat found by DXA was 4.3% higher. The differences between results by the two methods for individuals were from -11.5% to 2.7%, and the differences were negatively correlated with BMC/fat-free weight (FFW ; r=-0.82, p < 0.01) and BMD (r=-0.85, p<0.01) . Fat-free body density ranged from 1.097 to 1.111 g/cm<SUP>3</SUP>because BMC/FFWs varied with the individual. We concluded that individual differences in BMC/FFW and BMD affected the fat-free body density. The variations in fat-free body density would give rise to systematic errors in body composition measured underwater.

Prediction of pulmonary residual volume from anthropometric measurements and its applicability to calculate body density in underwater weighing method / 体力科学

The purpose of the present study was to derive regression equation based on anthropometric measurements to estimate pulmonary residual volume (RV) and to ascertain its applicability in calculation of body density (BD) . Subjects were 30 males and 25 females living in Santa Barbara, California, USA, ranging in age 17 to 52 years.<BR>Nine anthropometric measurements, actual RV, vital capacity (VC), and BD using the conventional underwater weighing method were made on each subject. In males four measurements (age, height, biiliac diameter, and chest diameter) were selected by Wherry-Doolittle test selection method. Likewise, four measurements (height, age, shoulder circumference, and chest diameter) were selected in females. The prediction formulas obtained by using these measurements were as follows:<BR>(1) RV=38.89 (X1) +30.43 (X2) -12.43 (X3) +10.70 (X4) -4573.4 (formales)<BR>(R=0.832, SEE =251.9 m<I>l</I>)<BR>where RV: predicted RV (m<I>l</I>), X1: age (years), X2: height (cm), X3: biiliac diameter (mm), X4: chest diameter (mm), R: multiple correlation coefficient, SEE: standard error of estimation.<BR>(2) RV=26.21 (X1) +8.71 (X2) -4.71 (X3) +12.94 (X4) -1284.2 (for females)<BR>(R=0.768, SEE =225.9 m<I>l</I>)<BR>where X1: height (cm), X2: age (years), X3: shoulder circumference (mm), X4: chest diameter (mm) .<BR>When these formulas were used to calculate RV, mean absolute differences between BDs obtained by using measured and the predicted RVs were 0.00331 g/cm<SUP>3</SUP> for males and 0.00353 g/cm<SUP>3</SUP> for females. On the other hand, the absolute differences using the formula of Goldman and Becklake, the fractions of VC, and the constant values were 0.0047 g/cm<SUP>3</SUP>, 0.00763 g/cm<SUP>3</SUP>, and 0.00787 g/cm<SUP>3</SUP> for males, 0.00642 g/cm<SUP>3</SUP>, 0.00646 g/cm<SUP>3</SUP>, and 0.00620 g/cm<SUP>3</SUP> for females respectively.<BR>It was concluded that using the formulas obtained in the present study to predict RV would be a useful method in the situation where mass management were nessesary and more precise measurements were required than the other simplified estimations. Because in predicting RV our formulas could largely diminish the extent of the potential error as compared with the other predictions. In addition they would not require special knowledge, technique, and devises.

ANTHROPOMETRY AND FAT STORE DURING PREGNANCY / 营养学报

Weight gain, skinfold thickness, circumference and body density were measured in 30 primiparous women aged from. 23-31 years (averaged 26.3 years old).The average body weight gained 13kg from 6 to 37 weeks of pregnancy.The suprailiac skinfold thickness in 24-37 weeks and the subscapular skinfold thickness in 37 weeks increased significantly from the 6th week of pregnancy, but the triceps and biceps skinfold thickness did not change significantly. The density of the body in 24th and 37th week of pregnancy decreased significantly.The change and the body fat (%) calculated by means of 4 skinfolds increased in 3.7% (5.7kg of fat). The mean values of the hip circumference in 24th and 37th week were significantly different from that in 6th week of pregnancy. The upper thigh in the 24th and 37th week also increased slightly but not significantly different as compared with the 6th week. The mean values of arm, mid-thigh and calf circumference did not change during pregnancy.