Relationship between adiposity and body size reveals limitations of BMI

Research Institute of Healthcare Sciences, University of Wolverhampton, WS1 3BD Walsall, UK.
American Journal of Physical Anthropology (Impact Factor: 2.38). 01/2006; 129(1):151-6. DOI: 10.1002/ajpa.20262
Source: PubMed


The aims of this study were to assess 1) whether the stature-adjusted body mass index (BMI) is a valid proxy for adiposity across both athletic and nonathletic populations, and 2) whether skinfold measurements increase in proportion to body size, thus obeying the principle of geometric similarity. The research design was cross-sectional, allowing the relationship between skinfold calliper readings (at eight sites and between specific athletic and nonathletic groups, n = 478) and body size (either mass, stature, or both) to be explored both collectively, using proportional allometric MANCOVA, and individually (for each site) with follow-up ANCOVAs. Skinfolds increase at a much greater rate relative to body mass than that assumed by geometric similarity, but taller subjects had less rather than more adiposity, calling into question the use of the traditional skinfold-stature adjustment, 170.18/stature. The best body-size index reflective of skinfold measurements was a stature-adjusted body mass index similar to the BMI. However, sporting differences in skinfold thickness persisted, having controlled for differences in body size (approximate BMI) and age, with male strength- and speed-trained athletes having significantly lower skinfolds (32% and 23%, respectively) compared with controls. Similarly, female strength athletes had 29% lower skinfold measurements compared to controls, having controlled for body size and age. These results cast serious doubts on the validity of BMI to represent adiposity accurately and its ability to differentiate between populations. These findings suggest a more valid (less biased) assessment of fatness will be obtained using surface anthropometry such as skinfolds taken by experienced practitioners following established procedures.

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    • "Increased body fat is usually accompanied by increased total body mass; therefore, indices of relative weight are commonly used to diagnose obesity. One of the most commonly used indices of relative weight is body mass index (BMI), which is an accepted index to characterize obesity in individuals and most widely used in epidemiological studies.5 BMI is very useful; however, despite its widespread use, it is only a surrogate measurement of body fat, and it does not provide an accurate measurement of body composition,6 and may be influenced by age, sex, and ethnicity.7 Moreover, adipose tissue is responsible for the majority of obesity-associated diseases; therefore, complex and expensive methods, such as dual-energy X-ray absorption (DXA) or magnetic resonance imaging, must be used to measure body fat accurately.8,9 "
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    ABSTRACT: Purpose Obesity is a major public health issue and is associated with many metabolic abnormalities. Consequently, the assessment of obesity is very important. A new measurement, the body adiposity index (BAI), has recently been proposed to provide valid estimates of body fat percentages. The objective of this study was to compare the BAI and body mass index (BMI) as measurements of body adiposity and metabolic risk. Materials and Methods This was a cross-sectional analysis performed on Korean women. The weight, height, and hip circumferences of 2950 women (mean age 25±5 years old, 18-39 years) were measured, and their BMI and BAI [hip circumference (cm)/height (m)1.5-18] values were calculated. Bioelectric impedance analysis was used to evaluate body fat content. Glucose tolerance status was assessed with a 75-g oral glucose tolerance test, and insulin sensitivity was estimated with the insulin sensitivity index. Results BMI was more significantly correlated with fat mass and fat percentage. Additionally, BMI was also more significantly associated with metabolic parameters, including fasting glucose, post-load 2-h glucose, fasting insulin, post-load 2-h insulin, triglycerides, and high density lipoprotein cholesterol than BAI. Receiver operating characteristic curve analysis revealed that BMI was a better tool for predicting body fat percentage than BAI. Insulin sensitivity and metabolic syndrome were more significantly associated with BMI than with BAI. Conclusion In Korean women, the current BMI-based classifications for obesity might be superior to BAI-based measurements for determining obesity and predicting metabolic risk.
    Full-text · Article · Jul 2014 · Yonsei Medical Journal
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    • "Although the positive relation between chronic diseases and body mass index (BMI) as an indicator of general obesity has been well established, some limitations remain to be considered. Lack of discerning between fat and muscle mass and not declaring the fat distribution are two important limitations of BMI [14] [15] [16]. These limitations are worthwhile because central obesity is associated with increased risk for non-communicable chronic diseases. "
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    ABSTRACT: Several studies have concluded a positive association between abdominal obesity, general obesity, and chronic diseases. However, the best anthropometric measures to predict the risk for chronic diseases should be clarified in each population. Therefore, the aim of this study was to compare the predictive power of A Body Shape Index (ABSI), body mass index (BMI), and waist-to-height ratio and Clinica Universidad de Navarra-Body Adiposity Estimator for metabolic syndrome (MetS) and cardiovascular disease (CVD) risks among Iranians in different age and sex categories. This population-based cross-sectional study conducted on 9555 individuals, ages ≥19 y. Anthropometric measures, blood pressure, and biochemical markers were measured using standard protocols. Hypertension, hyperglycemia, hypercholesterolemia, high low-density lipoprotein cholesterol and low high-density lipoprotein cholesterol levels were considered as the CVD risks. Mean (SD) of age and BMI of participants were 38.7 y (mean 15.5) and 25.7 kg/m(2) (mean 4.6), respectively. ABSI demonstrated the weakest correlations and lowest area under curve (AUC) for various risk factors and MetS. However, the highest odds ratio was observed for ABSI and MetS in different age and sex categories. Based on the AUC, we concluded that ABSI is a weak predictor for CVD risks and MetS. More studies are needed to determine the best predictor of CVD risk among the Iranian population.
    Full-text · Article · Jun 2014 · Nutrition
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    • "This finding is in agreement with the data of Pasco et al. [24] who indicated that in a large sample of both sexes, BMI overestimates body fat in males mostly due to their higher muscularity and bone mass. Similarly, Nevill et al. [25] noted that BMI does not differentiate the adiposity in male and female subjects aged 24.8 to 31.7 years, classified according to training status as athletes and controls. "
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    ABSTRACT: Background Limited data have indicated that body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and waist to height ratio (WHtR) of athletes and young adults provide misleading results concerning body fat content. This study was aimed at the evaluation of the relationship between different surrogate indices of fatness (BMI, WC, WHR, WHtR and body adiposity index (BAI)) with the percentage of body fat in Polish students with respect to their sex and physical activity. Methods A total of 272 students volunteered to participate in the study. Of these students, 177 physical education students (90 males and 87 females) were accepted as active (physical activity of 7 to 9 hours/week); and 95 students of other specializations (49 males and 46 females) were accepted as sedentary (physical activity of 1.5 hours/week). Weight, height, waist and hip circumferences were measured, and BMI, WHR, WHtR and BAI were calculated. Body fat percentage was assessed using four skinfold measurements. Results Classification of fatness according to the BMI and the percentage of body fat have indicated that BMI overestimates fatness in lean subjects (active men and women, sedentary men), but underestimates body fat in obese subjects (sedentary women). In all groups, BMI, WHR, WHtR and BAI were significantly correlated with the percentage of body fat (with the exception of WHR and hip circumference in active and sedentary women, respectively). However, coefficients of determination not exceeding 50% and Lin’s concordance correlation coefficients lower than 0.9 indicated no relationship between measured and calculated body fat. Conclusion The findings in the present study support the concept that irrespective of physical activity and sex none of the calculated indices of fatness are useful in the determination of body fat in young adults. Thus, it seems that easily calculated indices may contribute to distorted body image and unhealthy dietary habits observed in many young adults in Western countries, but also in female athletes.
    Full-text · Article · May 2014 · Journal of PHYSIOLOGICAL ANTHROPOLOGY
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