Raw bioelectrical impedance measurements are not different between White and Black adults when matched for sex, age, BMI, and other physical characteristics

Differences in Perceptual and Attitudinal Body Image Between White and African-American Adults Matched for Sex, Age, and Body Composition

PURPOSE

The purpose of this study was to evaluate the differences in perceptual and attitudinal body image between White and African-American males and females matched for sex, age, BMI, and other body composition components using a combination of 3-dimensional mobile digital imaging analysis (DIA) and the Multidimensional Body-Self Relations Questionnaire-Appearance Scale (MBSRQ-AS).

METHODS

One-hundred non-Hispanic White (n=50) and non-Hispanic African-American (n=50) adults (M=34, F=66) matched for sex, age, BMI, and body composition components completed this cross-sectional study. Participants underwent several anthropometric assessments, completed the MBSRQ-AS, and rated their perceived appearance, ideal appearance, and the appearance they believed a partner would find societally attractive using a state of the art mobile 3-dimensional DIA produced using broad developmental populations. Body image distortion was measured as the perceived minus actual appearance, and body image dissatisfaction was defined as the ideal appearance and appearance a partner would find attractive minus the perceived appearance.

RESULTS

Using the DIA, only African-American females demonstrated significant body image distortion (p<0.001); reporting perceived appearances significantly lower their than their actual. Further, AA females demonstrated significantly larger differences between their ideal and perceived appearance (p=0.009), perceived larger bodies as more attractive to a potential partner (p=0.009), and reported higher ratings of appearance evaluation (p=0.001) and body area satisfaction (p=0.011) compared to White females.

CONCLUSIONS

After accounting for all anthropometric determinants of body image, perceptual and attitudinal body image differs between White and African-American adults with differences supporting larger body size acceptance for African-American individuals, particularly African-American females.

Near-infrared reactance spectroscopy-derived visceral adipose tissue for the assessment of metabolic syndrome in a multi-ethnic sample of young adults

OBJECTIVES

Visceral adipose tissue (VAT) is highly associated with metabolic syndrome (MetS), which is rapidly increasing in young adults. However, accessible VAT measurement methods are limited, restricting the use of VAT in early detection. This cross-sectional study sought to determine if near-infrared reactance spectroscopy (NIRS)-derived VAT (VATNIRS) was associated with MetS in a multi-ethnic sample of young adults.

METHODS

A total of 107 male and female (F:62, M:45) participants (age: 23.0 ± 4.3y; BMI: 27.1 ± 6.6 kg/m2) completed measurements of fasting blood pressure, blood glucose (FBG), blood lipids, and anthropometric assessments including waist circumference and VATNIRS. MetS severity (MetSindex) was calculated from the aforementioned risk factors using sex and race-specific equations.

RESULTS

VATNIRS was higher in participants with, and at risk for, MetS compared to those with lower risks (all p < .001). VATNIRS was positively associated with MetSindex for all groups (all p < .001). VATNIRS showed positive associations with systolic (SBP), diastolic (DBP), and mean arterial pressure (MAP), LDL-C and LDL-C-related biomarkers, and FBG; and negative associations with HDL-C and HDL-C-to-total cholesterol ratio (all p < .050). Associations between VATNIRS and blood pressure for females, and LDL-C and LDL-C-related biomarkers for males, were nonsignificant (all p > .050). VATNIRS was positively associated with DBP in African-American participants, and SBP in White participants, resulting in positive associations with MAP for both groups (all p < .050).

CONCLUSIONS

VATNIRS is associated with MetS and individual MetS risks factors in a multi-ethnic sample of young adults; providing a noninvasive, cost-effective, portable, and accessible method that may assist in the early detection of MetS and other cardiometabolic abnormalities.

Conflicting Associations among Bioelectrical Impedance and Cardiometabolic Health Parameters in Young White and Black Adults

PURPOSE

The purpose of this cross-sectional evaluation was to determine the associations between raw bioelectrical impedance and cardiometabolic health parameters in a sample of young non-Hispanic White and African American adults.

METHODS

A total of 96 (female: 52, male: 44) non-Hispanic White ( n = 45) and African American adults ( n = 51) between the ages of 19 and 37 yr (22.7 ± 3.83 yr) completed several fasted assessments including resting systolic blood pressure (rSBP), blood glucose (FBG), blood lipids, and bioelectrical impedance spectroscopy. Bioelectrical impedance spectroscopy-derived measurements included phase angle, bioimpedance index (BI), impedance ratio (IR), reactance index (XCi), fat-free mass (FFM), FFM index (FFMi), and absolute (a) and relative (%) total body water (TBW) and extracellular (ECF) and intracellular fluid (ICF). All bioelectric variables were collected at 50 kHz other than IR (250 kHz/5 kHz). Multiple regressions were conducted and adjusted for sex, age, and body mass index.

RESULTS

rSBP was positively, and HDL was inversely, associated with all bioelectrical impedance and absolute hydration variables (all P ≤ 0.050) other than XCi for rSBP and XCi and FFMi for HDL. rSBP ( P < 0.001) was inversely, and HDL ( P = 0.034) was positively, associated with IR. FBG was positively associated with BI, XCi, FFM, TBWa, and ECFa (all P < 0.050). Metabolic syndrome severity was positively associated with BI, FFM, TBWa, and ECFa for women (all P ≤ 0.050) and with ICFa for African American women ( P = 0.016).

CONCLUSIONS

Given the rapid increase in the prevalence of cardiometabolic health risks among young adults and the broad use of bioelectrical impedance in practice, the conflicting associations we observed in this age group suggest that bioelectrical impedance parameters should be used with caution in the context of cardiometabolic health risks and age.

Development and validation of new bioelectrical impedance equations to accurately estimate fat mass percentage in a heterogeneous Caucasian population

Fat mass percentage (%FM) is frequently determined by nutritionists and personal trainers with bioelectrical impedance analysis (BIA) devices. The aims of the present study were: (1) to develop new regression equations using dual-energy X-ray absorptiometry (DXA) as the reference method for estimating %FM in a heterogeneous Caucasian population with a foot-to-hand device (BIA-101) and a hand-to-hand device (BIA-TELELAB) and (2) to compare the new equations with the manufacturers' equations. We hypothesized that the new equations would lead to more accurate estimations compared with DXA. A total of 218 healthy Caucasian participants aged 18 to 65 years were divided into a development group and a validation group. The accuracy of the different equations was assessed by mean differences, coefficient of determination, standard error of the estimate (SEE), intraclass correlation coefficients (ICC), and Bland-Altman plots. The proposed equation for BIA-101 explained 90.0% of the variance in the DXA-derived %FM, with a low random error (SEE = 2.98%), excellent agreement (ICC = 0.94), no fixed bias, and relatively low individual variability (5.86%). For BIA-TELELAB, the proposed equation explained 88.0% of the variance in the DXA-derived %FM, with a low random error (SEE = 3.27%), excellent agreement (ICC = 0.93), no fixed bias, and relatively low individual variability (6.37%). The results obtained for the manufacturers' equations confirm that these equations are not a good option for %FM assessment. As hypothesized, the new regression equations for BIA-101 and BIA-TELELAB devices can accurately estimate %FM in a heterogeneous Caucasian population with a broad age range.

The effect of postural orientation on body composition and total body water estimates produced by smartwatch bioelectrical impedance analysis: an intra- and inter-device evaluation

Advances in wearable technologies now allow modern smartwatches to collect body composition estimates through bioelectrical impedance techniques embedded within their design. However, this technique is susceptible to increased measurement error when postural changes alter body fluid distribution. The purpose of this study was to evaluate the effects of postural orientation on body composition and total body water (TBW) estimates produced by smartwatch bioelectrical impedance analysis (SWBIA) and determine its agreement with criterion measures. For this cross-sectional evaluation, 117 (age: 21.4±3.0 y; BMI: 25.3±5.7 kg/m2) participants (F:69, M:48) completed SWBIA measurements while in the seated, standing, and supine positions, then underwent criterion dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance spectroscopy (BIS) assessments. In the combined sample and females, body fat percent, fat mass, and fat-free mass using SWBIA were significantly different between the supine and standing positions (all p<0.001), though group level agreement with DXA was similar across positions. Supine SWBIA TBW estimates were significantly different between seated and standing estimates (all p≤0.026), but further analyses revealed that this was driven by the supine and seated differences observed in females (p=0.003). SWBIA TBW demonstrated similar group and individual level agreement with BIS across body positions with slight improvements observed during seated and supine assessments for females and males, respectively. SWBIA may demonstrate slight intra- and inter-device differences in body composition and TBW when measured across postural orientations, though further evaluations in external/clinical samples are necessary. While sex/position-specific guidelines may improve precision, these findings highlight the importance of standardized body positioning when using SWBIA.

Associations between eating behaviors and metabolic syndrome severity in young adults

Metabolic syndrome (MetS), a precursor to cardiovascular disease and type II diabetes, is rapidly increasing in young adults. Accordingly, earlier interventions aimed at combating the onset of MetS in young adults are required. However, current behavioral interventions have failed to consider the eating behaviors that precede disease development, likely contributing to the consistently high failure rates of these interventions. The purpose of this cross-sectional study was to evaluate the associations between eating behaviors and MetS severity (MetSindex) in a sample of young adults. A sample of 104 (non-Hispanic White: 45; non-Hispanic Black: 49; Hispanic White: 5; Asian: 5) young adult (age: 23.1 ± 4.4) males and females (F:61, M:43) completed anthropometric, blood pressure, blood glucose, and blood lipid assessments; each of which were used to calculate a continuous MetSindex score. Participants also completed the revised version of the 18-item Three-factor Eating Questionnaire to measure emotional eating (EmE), uncontrolled eating (UE), and cognitive restraint (CR). EmE was positively associated with MetSindex for young adult females (p = 0.033) and non-Hispanic Black participants (p = 0.050), but not male (p = 0.506) or non-Hispanic White participants (p = 0.558). Additionally, MetSindex was greater in the highest EmE tertile compared to the lowest EmE tertile for the total sample (p = 0.037) and young adult females (p = 0.015). UE and CR were not associated with MetSindex. These data suggest a potential link between EmE and MetS severity in young adults, and that behavioral interventions aimed at MetS prevention should focus on treating the underlying EmE behaviors common in young adults, particularly for young female and Black adults at the greatest risk.

Hemodynamic responses to handgrip and metaboreflex activation are exaggerated in individuals with metabolic syndrome independent of resting blood pressure, waist circumference, and fasting blood glucose

Introduction: Prior studies report conflicting evidence regarding exercise pressor and metaboreflex responses in individuals with metabolic syndrome (MetS). Purpose: To test the hypotheses that 1) exercise pressor and metaboreflex responses are exaggerated in MetS and 2) these differences may be explained by elevated resting blood pressure. Methods: Blood pressure and heart rate (HR) were evaluated in 26 participants (13 MetS) during 2 min of handgrip exercise followed by 3 min of post-exercise circulatory occlusion (PECO). Systolic (SBP), diastolic (DBP), and mean arterial pressure (MAP), along with HR and a cumulative blood pressure index (BPI), were compared between groups using independent samples t-tests, and analyses of covariance were used to adjust for differences in resting blood pressure, fasting blood glucose (FBG), and waist circumference (WC). Results: ΔSBP (∼78% and ∼54%), ΔMAP (∼67% and ∼55%), and BPI (∼16% and ∼20%) responses were significantly exaggerated in individuals with MetS during handgrip and PECO, respectively (all p ≤ 0.04). ΔDBP, ΔMAP, and BPI responses during handgrip remained significantly different between groups after independently covarying for resting blood pressure (p < 0.01), and after simultaneously covarying for resting blood pressure, FBG, and WC (p ≤ 0.03). Likewise, peak SBP, DBP, MAP, and BPI responses during PECO remained significantly different between groups after adjusting for resting blood pressure (p ≤ 0.03), with peak SBP, MAP, and BPI response remaining different between groups after adjusting for all three covariates simultaneously (p ≤ 0.04). Conclusion: These data suggest that exercise pressor and metaboreflex responses are significantly exaggerated in MetS independent of differences in resting blood pressure, FBG, or WC.