Validation of five simple models estimating body fat in white postmenopausal women: use in clinical practice and research

Prediction of body fat percentage: Development and validation of new anthropometric equations

INTRODUCTION

The aim of this study was to test the validity of existing equations, retrieved from the literature, in the Algerian adult population. To develop, and validate, new predictive equations for body fat percentage (%BF) using simple and easy-to-measure anthropometric parameters.

METHODS

This is a cross-sectional study including 877 Algerian adults who underwent a body composition assessment by the direct segmental multi-frequency bioelectrical impedance technique (Inbody-770). Participants were randomly divided into two groups: the development group (n = 577) and the validation group (n = 300). To develop the equations, multiple linear regression models were analyzed. The predictive performance of the developed equations was compared with the direct technique. The following validation tests were used: Student's t-test for paired samples, correlation, and Bland-Altman diagram. Diagnostic accuracy has also been assessed.

RESULTS

Four existing equations were tested, and all showed statically significant bias. Four new equations were developed; all had satisfactory predictive performance, with a correlation coefficient ranging from 0.72 to 0.94 in men and 0.87 to 0.93 in women. The best-fitting equation was based on body mass index, waist-to-hip ratio, and chest circumference. The diagnostic accuracy of this equation was 96.7% in men and 95.3% in women.

CONCLUSION

The newly developed equations based on anthropometric parameters can serve as a simple tool for the accurate prediction of BF% in adult subjects, at both individual and epidemiological levels.

Criterion-Related Validity of Field-Based Methods and Equations for Body Composition Estimation in Adults: A Systematic Review

PURPOSE OF REVIEW

Overweight and obesity are associated to health prognosis. Therefore, body composition assessment is an important health outcome, especially in adult population. We analyzed the criterion-related validity of existing field-based methods and equations for body composition estimation in adults aged 19-64 years.

RECENT FINDINGS

One hundred studies met inclusion criteria. The field-based methods, waist circumference (WC), body adiposity index (BAI), and body mass index (BMI) are valid to indicate body adiposity. Likewise, several equations, including the classical Durnin/Womersley equation, Jackson/Pollock equation (males), and Jackson, Pollock, and Ward equation (females), are valid to estimate total body fat mass or body fat percentage. Anthropometric field methods can provide a simple, quick, and easy informative indicators of adiposity in adults. Classical equations, such as Durnin/Womersley equation, Jackson/Pollock equation, and Jackson, Pollock, and Ward equation, are still valid to estimate total body fat mass or body fat percentage in adult population. When choosing estimation equations, specific population characteristics, such as age, weight status, or race ethnicity, should be taken into account. (Trial Registration: Registered on PROSPERO (CRD42020194272)).

Osteosarcopenic obesity, the coexistence of osteoporosis, sarcopenia and obesity and consequences in the quality of life in older adults ≥65 years-old in Greece

OBJECTIVE

We investigated the coexistence of sarcopenia and obesity in older adults≥65 years diagnosed with osteoporosis and the association with Quality of Life (QoL).

METHODS

A Cross-sectional survey has been performed on a randomized sample of 50 diagnosed osteoporotic elderly people from both sexes (Men=16; Women=34).

MEASUREMENTS

Quantitative ultrasound was conducted to identify osteoporosis and defined with a T score ≤2.5. Validated anthropometric equations were used in order to estimate body fat percentage and skeletal muscle mass so as to detect the reallocation of body fat and lean muscle. 10m gait speed and hand grip strength was measured in order to diagnose sarcopenia according to European Society for Clinical Nutrition and Metabolism (ESPEN) algorithm. The evaluation of QoL was conducted using a QoL questionnaire specific to osteoporosis. The data were analyzed with descriptive statistics and a chi-square test was performed to examine if Osteosarcopenic Obesity (OSO) is sex related and the correlation between OSO and QoL.

RESULTS

From the 50 participants, 40%(n=19) were classified as people with OSO and 60%(n=31) without OSO. From n=19 people that experienced OSO women represent 20% (n=9) and men 18% (n=9); with the latter had a greater decline in muscle mass than women, while women had lower BMD than men according to the z score. OSO is not related with sex (p>.05) and there is no significant association between OSO and QoL (p> .05 for all the domains of QoL questionnaire).

CONCLUSION

Osteoporosis in the elderly often coexists with reduced muscle mass and muscle strength as well as an increase in adiposity and was independently associated with QoL. People that experience OSO presenting lower functionality that increases the risk for falls and bone fractures originated from the decline in bone and muscle mass, and increased adiposity. Increased awareness of OSO may help develop efficient interventions and public health policies for healthier and more active elderly people.

Equation Córdoba: A Simplified Method for Estimation of Body Fat (ECORE-BF)

BACKGROUND

Many methods for measuring body fat have been developed, but applications in clinical settings are limited. For this reason, researchers have tried to identify different formulas for its estimation but most of are hard to incorporate into daily work due to the variability in population and difficulty of use. The aim of this study was to develop and validate a new equation for the simplified estimation of body fat using the Clínica Universidad de Navarra - Body Adiposity Estimator (CUN-BAE) as a reference.

METHODS

This research was conducted in two phases. In the first, the new body fat estimation equation was developed. The developed equation was validated in the second phase. Pearson's linear correlation, raw and adjusted linear regressions, the intraclass correlation coefficient, and Bland-Altman graphs were used.

RESULTS

The variables that best adjusted the body fat percentage were age, sex, and the Napierian logarithm of Body Mass Index (LnBMI), forming the Equation Córdoba for Estimation of Body Fat (ECORE-BF) model. In its validation, the model presented correlation values of 0.994, an intraclass correlation coefficient of 0.960, with the Bland-Altman graph indicating means differences of 1.82 with respect to the estimation with the CUN-BAE. Nevertheless, although the aim was to simplify the CUN-BAE, the main limitation of this study is that a gold standard, such as air displacement plethysmography (ADP) or dual-energy X-ray absorptiometry (DXA), was not used.

CONCLUSIONS

The proposed equation (ECORE-BF) simplified the CUN-BAE and provided a precise method, respecting the principle of parsimony, for the calculation of body fat.

External Validation of Equations that Use Demographic and Anthropometric Measurements to Predict Percent Body Fat

OBJECTIVE

Numerous equation to predict percent body fat using demographics and anthropometrics have been published but external validation of these equations is limited. The objective of this study was to validate published equations that use anthropometrics for prediction of percent body fat using external data.

METHODS

Data were from the Visceral Fat, Metabolic Rate, and Coronary Heart Disease Risk I (VIM I) Study and the Fels Longitudinal Study (Fels). VIM I was conducted in a subset of subjects from the CARDIA study and included black and white adults 28-40 years (n = 392). Fels consisted of white participants 8-88 years (n = 1,044). Percent body fat assessed by dual X-ray absorptiometry (DXA) in these two studies was compared to results calculated using 13 equations from Stevens et al. and nine other published equations.

RESULTS

In general, the Stevens equations performed better than equations from other studies. For example, equation "I" in women in VIM I, Fels adults, and Fels youth, R2 estimates were 0.765, 0.757 and 0.789, respectively. In men the estimates were 0.702 in VIM I, 0.822 in Fels adults and 0.905 in Fels youth. None of the results from the nine published equations showed R2 this high in corresponding groups.

CONCLUSIONS

Our results indicate that several of the Stevens equations have external validity superior to that of nine other published equations among varying age groups, genders and races.

Prevalence of rheumatoid cachexia in rheumatoid arthritis: a systematic review and meta-analysis

BACKGROUND

Low muscle mass occurs in patients with rheumatoid arthritis without weight loss; this condition is referred as rheumatoid cachexia. The aim of the current study was to perform a systematic review with meta-analysis to determine the rheumatoid cachexia prevalence.

METHODS

A systematic review with meta-analysis of observational studies published in English, between 1994 and 2016, was conducted using MEDLINE (via PubMed) and other relevant sources. Search strategies were based on pre-defined keywords and medical subject headings. The methodological quality of included studies was assessed using the Newcastle-Ottawa Scale. Meta-analysis was used to estimate the prevalence, and because studies reported different methods and criteria to estimate body composition and prevalence of rheumatoid cachexia, subgroup analyses were performed. Meta-regression adjusted for the 28-joint disease activity score and disease duration (years) was performed (significance level at P ≤ 0.05).

RESULTS

Of 136 full articles (one duplicate publication) screened for inclusion in the study, eight were included. The estimated overall prevalence of rheumatoid cachexia was 19% [95% confidence interval (CI) 07-33%]. This prevalence was 29% (95% CI 15-46%) when body composition was measured by dual-energy X-ray absorptiometry. When the diagnostic criteria were fat-free mass index below the 10th percentile and fat mass index above the 25th percentile, rheumatoid cachexia prevalence was 32% (95% CI 14-52%). The 28-joint disease activity score and disease duration had no influence on the estimated prevalence of rheumatoid cachexia (P > 0.05). Most studies were rated as having moderate methodological quality.

CONCLUSIONS

Meta-analysis showed a prevalence of rheumatoid cachexia of 15-32%, according to different criteria, demonstrating that this condition is a frequent comorbidity of rheumatoid arthritis. To better understand its clinical impact, more studies using standardized definitions and prospective evaluations are urgently needed.

Development and validation of two equations based on anthropometry, estimating body fat for the Greek adult population

OBJECTIVE

To validate anthropometric equations in the current literature predicting body fat percentage (%BF) in the Greek population, to develop and validate two anthropometric equations estimating %BF, and to compare them with the retrieved equations.

METHODS

Anthropometric data from 642 Greek adults were incorporated. Dual-energy X-ray absorptiometry was used as reference method. The comparison with other equations was made using Bland-Altman analysis, intraclass correlation coefficient, and Lin's concordance correlation coefficient.

RESULTS

Nine of the thirty-one retrieved equations had no statistically significant bias. However, all of them had wide limits of agreement (±8.3 to ±16%BF). The equations accrued were: BF% = -0.615-10.948 × sex + 0.321 × waist circumference + 0.502 × hips circumference-0.39 × forearm circumference - 19.768 × height (m) and BF% = -27.787-5.515 × sex-8.419 × height + 0.145 × waist circumference + 0.270 × hips circumference + 7.509 × log of thigh skinfold + 20.090 × log of sum of skinfolds (bicep + tricep + suprailiac + subscapular)-0.445 × forearm circumference. Bland-Altman's reliability analysis showed no significant bias of -0.058 and -0.148%BF and limits of agreement ±8.100 and ±6.056%BF; the intraclass correlation coefficient was 0.955 and 0.976; and Lin's concordance correlation coefficient was 0.914 and 0.951, respectively.

CONCLUSIONS

Literature equations performed moderately on this study's population. Therefore, two equations were designed and validated. The first one was simple and easily applicable, with measures obtained from a measuring tape, and the second one more complicated yet more accurate and reliable. Both were found to be reliable for the assessment of body composition in the Greek population.

How Accurate Are the Anthropometry Equations in in Iranian Military Men in Predicting Body Composition?

BACKGROUND

The body composition varies according to different life styles (i.e. intake calories and caloric expenditure). Therefore, it is wise to record military personnel's body composition periodically and encourage those who abide to the regulations. Different methods have been introduced for body composition assessment: invasive and non-invasive. Amongst them, the Jackson and Pollock equation is most popular.

OBJECTIVES

The recommended anthropometric prediction equations for assessing men's body composition were compared with dual-energy X-ray absorptiometry (DEXA) gold standard to develop a modified equation to assess body composition and obesity quantitatively among Iranian military men.

PATIENTS AND METHODS

A total of 101 military men aged 23 - 52 years old with a mean age of 35.5 years were recruited and evaluated in the present study (average height, 173.9 cm and weight, 81.5 kg). The body-fat percentages of subjects were assessed both with anthropometric assessment and DEXA scan. The data obtained from these two methods were then compared using multiple regression analysis.

RESULTS

The mean and standard deviation of body fat percentage of the DEXA assessment was 21.2 ± 4.3 and body fat percentage obtained from three Jackson and Pollock 3-, 4- and 7-site equations were 21.1 ± 5.8, 22.2 ± 6.0 and 20.9 ± 5.7, respectively. There was a strong correlation between these three equations and DEXA (R² = 0.98).

CONCLUSIONS

The mean percentage of body fat obtained from the three equations of Jackson and Pollock was very close to that of body fat obtained from DEXA; however, we suggest using a modified Jackson-Pollock 3-site equation for volunteer military men because the 3-site equation analysis method is simpler and faster than other methods.

Regional fat distribution and cardiometabolic risk in healthy postmenopausal women

BACKGROUND

Regional fat distribution is an important determinant of cardiometabolic risk after menopause. The aim of the present study was to investigate the association between indices of fat distribution obtained by Dual-energy X-ray Absorptiometry (DXA) and representative cardiometabolic risk factors in a cohort of healthy postmenopausal women.

METHODS

In this cross-sectional study, cardiometabolic risk factors were correlated with a variety of central and peripheral fat depots obtained by DXA, in a total of 150 postmenopausal women, free of diabetes and cardiovascular disease (age 54 ± 7 years, BMI 29.6 ± 5.8 kg/m(2), mean ± 1 SD).

RESULTS

After adjusting for age and total adiposity, DXA-derived indices of central and peripheral fat distribution displayed opposite associations (positive versus negative) with the examined cardiometabolic risk factors. In multivariate regression analysis, thoracic fat mass % was an independent predictor of blood pressure, HOMA index and triglycerides, abdominal fat mass % was an independent predictor of high sensitivity C-reactive protein, and abdominal-to-gluteofemoral fat ratio was an independent predictor of high density lipoprotein cholesterol. An index of peripheral fat distribution, gluteofemoral fat mass %, proved to be the most important determinant of metabolic syndrome (Odds Ratio 0.76, 95% confidence intervals 0.67-0.87, p<0.001), independent of total and central adiposity.

CONCLUSION

DXA-derived indices of regional fat distribution such as thoracic, abdominal and gluteofemoral fat, correlate significantly with cardiometabolic risk factors in healthy postmenopausal women, and may serve as clinically useful tools for evaluating cardiometabolic risk after menopause.

Development and validation of anthropometric equations to estimate appendicular muscle mass in elderly women

OBJECTIVE

This study aimed to examine the cross validity of two anthropometric equations commonly used and propose simple anthropometric equations to estimate appendicular muscle mass (AMM) in elderly women.

METHODS

Among 234 physically active and functionally independent elderly women, 101 (60 to 89 years) were selected through simple drawing to compose the study sample. The paired t test and the Pearson correlation coefficient were used to perform cross-validation and concordance was verified by intraclass correction coefficient (ICC) and by the Bland and Altman technique. To propose predictive models, multiple linear regression analysis, anthropometric measures of body mass (BM), height, girth, skinfolds, body mass index (BMI) were used, and muscle perimeters were included in the analysis as independent variables. Dual-Energy X-ray Absorptiometry (AMMDXA) was used as criterion measurement. The sample power calculations were carried out by Post Hoc Compute Achieved Power. Sample power values from 0.88 to 0.91 were observed.

RESULTS

When compared, the two equations tested differed significantly from the AMMDXA (p <0.001 and p = 0.001). Ten population / specific anthropometric equations were developed to estimate AMM, among them, three equations achieved all validation criteria used: AMM (E2) = 4.150 +0.251 [bodymass (BM)] - 0.411 [bodymass index (BMI)] + 0.011 [Right forearm perimeter (PANTd) 2]; AMM (E3) = 4.087 + 0.255 (BM) - 0.371 (BMI) + 0.011 (PANTd) 2 - 0.035 [thigh skinfold (DCCO)]; MMA (E6) = 2.855 + 0.298 (BM) + 0.019 (Age) - 0,082 [hip circumference (PQUAD)] + 0.400 (PANTd) - 0.332 (BMI). The equations estimated the criterion method (p = 0.056 p = 0.158), and explained from 0.69% to 0.74% of variations observed in AMMDXA with low standard errors of the estimate (1.36 to 1.55 kg) and high concordance (ICC between 0,90 and 0.91 and concordance limits from -2,93 to 2,33 kg).

CONCLUSION

The equations tested were not valid for use in physically active and functionally independent elderly women. The simple anthropometric equations developed in this study showed good practical applicability and high validity to estimate AMM in elderly women.