Body composition and body fat distribution are related to cardiac autonomic control in non-alcoholic fatty liver disease patients

BACKGROUND/OBJECTIVES: Heart rate recovery (HRR), a cardiac autonomic control marker, was shown to be related to body composition (BC), yet this was not tested in non-alcoholic fatty liver disease (NAFLD) patients. The aim of this study was to determine if, and to what extent, markers of BC and body fat (BF) distribution are related to cardiac autonomic control in NAFLD patients. SUBJECTS/METHODS: BC was assessed with dual-energy X-ray absorptiometry in 28 NAFLD patients (19 men, 51±13 years, and 9 women, 47±13 years). BF depots ratios were calculated to assess BF distribution. Subjects’ HRR was recorded 1 (HRR1) and 2 min (HRR2) immediately after a maximum graded exercise test. RESULTS: BC and BF distribution were related to HRR; particularly weight, trunk BF and trunk BF-to-appendicular BF ratio showed a negative relation with HRR1 (r 1⁄4 0.613, r 1⁄4 0.597 and r 1⁄4 0.547, respectively, Po0.01) and HRR2 (r 1⁄4 0.484, r 1⁄4 0.446, Po0.05, and r 1⁄4 0.590, Po0.01, respectively). Age seems to be related to both HRR1 and HRR2 except when controlled for BF distribution. The preferred model in multiple regression should include trunk BF-to-appendicular BF ratio and BF to predict HRR1 (r2 1⁄4 0.549; Po0.05), and trunk BF-to-appendicular BF ratio alone to predict HRR2 (r2 1⁄4 0.430; Po0.001). CONCLUSIONS: BC and BF distribution were related to HRR in NAFLD patients. Trunk BF-to-appendicular BF ratio was the best independent predictor of HRR and therefore may be best related to cardiovascular increased risk, and possibly act as a mediator in age-related cardiac autonomic control variation.info:eu-repo/semantics/publishedVersio

THE AGREEMENT OF BODY FAT PERCENTAGE ESTIMATES FROM ULTRASOUND, SKINFOLD, AND AN UNDERWATER WEIGHING CRITERION

Katherine Sullivan, Casey J. Metoyer, Michael R. Esco, Michael V. Fedewa. University of Alabama, Tuscaloosa, AL. BACKGROUND: Accurate measures of body composition are clinically important, as higher adiposity is associated with various unfavorable health outcomes. Ultrasound has been proposed as a viable alternative to skinfold (SKF) thickness for the estimation of body fat (%Fat) as it may overcome reliability concerns often associated with SKF measurement. However, ultrasound has not been extensively examined in generally healthy, young adults. Therefore, the purpose of this study was to examine the agreement between %Fat from ultrasound (%FatUS), skinfold thickness (%FatSKF), and an underwater weighing (%FatUWW) criterion. METHODS: A convenience sample of 46 young adults were included in our analysis (28.3% female, 82.6% Caucasian, 22.8±4.1 yrs., 24.3±3.5 kg/m2). Ultrasound and SKF measurements were taken on the same seven standardized sites on the right side of the body by the same evaluator. For each participant, two SKF and ultrasound measures were taken at each site. For each measurement site, the two SKF and ultrasound measures were averaged. The averaged SKF site measures were then summed. The averaged ultrasound site measures were converted to millimeters, doubled, and then summed. The sum of SKF and ultrasound measures were used separately to calculate body density via the gender specific Jackson and Pollock equations. Body density via underwater weighing (UWW) served as the criterion measure. Subsequently, %FatUS, %FatSKF, and %FatUWW were calculated using the Siri equation (%Fat = [495/body density] - 450). A repeated measures ANOVA examined potential differences between %FatUS, %FatSKF, and %FatUWW. Data are presented as mean ± standard deviation, with p\u3c0.05 used to determine statistical significance. RESULTS: A small, non-significant mean difference was observed between %FatUS (19.3±9.1 %Fat) and %FatUWW (18.1±6.8 %Fat) (ES=0.18, p = 0.11). A small, but statistically significant, mean difference was observed between %FatSKF (19.3±7.1 %Fat) and %FatUWW (18.1±6.8 %Fat) (ES=0.18, p = 0.05). Both, %FatUS (r =.818, SEE=3.9 %Fat, p\u3c.001) and %FatSKF (r =.808, SEE=4.0 %Fat, p\u3c.001) yielded similar agreement with %FatUWW. CONCLUSIONS: Ultrasound and SKF were comparable to UWW when measured using Jackson and Pollock’s 7-site body density equations. However, the time burden to participants and added financial cost may not justify the utility of ultrasound within generally healthy, young adults

ABSOLUTE PEAK OXYGEN CONSUMPTION IS INDEPENDENTLY CORRELATED WITH FAT-FREE MASS IN YOUTH SOCCER PLAYERS

Casey J. Metoyer, Oleg Sinelnikov, Michael V. Fedewa, Michael R. Esco, FACSM. The University of Alabama, Tuscaloosa, AL. BACKGROUND: It has been suggested that the relationship between body mass (BM) and peak oxygen consumption (VO2peak) is explained by fat-free mass (FFM) and not fat mass (FM). However, most of the research has occurred in children and adults with obesity, and hence, little is known about these relationships in youth athletes. Therefore, the purpose of the study was to determine the extent of variation in absolute VO2peak that can be independently explained by BM, FM, and FFM in youth soccer players. METHODS: A sample of 20 young male soccer players (age = 13.7 ± 0.8 years, height = 167.0 ± 7.9 cm, weight = 56.2 ± 8.4 kg) participated in this study. Absolute VO2peak was determined from a maximal graded exercise test on a treadmill. Dual-energy x-ray absorptiometry was used to measure FM and FFM. Pearson correlation procedures were used to determine the relationships between absolute VO2peak and the body composition metrics. Stepwise regression was used to determine which body composition metric (BM, FM, or FFM) explained the greatest variation in absolute VO2peak. RESULTS: The average absolute VO2peak, FM, and FFM was 3.1 ± 0.6 L/min, 11.1 ± 2.9 kg, and 46.0 ± 6.9 kg, respectively. Significant correlations were found between VO2peak and BM (r = 0.88, p \u3c 0.001), FM (r = 0.46, p = 0.02), and FFM (r = 0.90, p \u3c 0.001). Stepwise regression showed that only FFM significantly explained the variance in absolute VO2peak (R2 = 0.81, p \u3c 0.001). CONCLUSIONS: The results of this study suggest that FFM explains the relationship between BM and absolute VO2peak in youth soccer players. FM does not display an independent relationship with VO2peak. Therefore, fatness and absolute VO2peak appear to be independent qualities in male youth soccer players. Further research is needed to verify these findings and clarify the relationship between body composition and oxygen consumption in youth athletes

MUSCULAR STRENGTH AS A PREDICTOR OF BONE MINERAL DENSITY IN COLLEGIATE FEMALE ATHLETES

Emily V. Witte1, Henry N. Williford2, FACSM, Michael R. Esco3, FACSM & Matthew D. Leatherwood2. 1Emporia State University, Emporia, KS; 2Auburn University at Montgomery, Montgomery, AL; 3University of Alabama, Tuscaloosa, AL; e-mail: [email protected] It has been well established that the frequency and duration of impact loading, age, body weight, and body composition are independently correlated with bone mineral density (BMD) in female athletes. However, very little is known about the relationship of strength, in addition to other anthropometric measures, and BMD. PURPOSE: The purpose of this study was to examine the relationship between muscular strength, muscular endurance, sport specific impact loading, age, body composition and body weight simultaneously in regards to BMD in collegiate female athletes. METHODS: Participants included apparently healthy collegiate female athletes from a variety of sports; tennis (n=7), basketball (n=8), soccer (n=7), cross country (n=2), cheer (n=2), and volleyball (n=4). Each subject reported twice during a seven day span to complete the assessments. During the first session, descriptive statistics such as height, weight, BMD and body composition were recorded. Additionally, objective assessments for muscular strength (hand-grip strength, one-repetition max bench press and squat strength), muscular endurance (push-ups and curl-ups) were performed. The second session included the evaluation of maximal oxygen consumption, obtained from a graded exercise test and open circuit spirometry. RESULTS: Using a Pearson correlation, bench press strength displayed the greatest relationship with BMD (r = 0.826). Significant relationships also existed between BMD and fat-free mass (r = 0.739), maximal squat strength (r = 0.666) and hand-grip strength (r = 0.597). A stepwise regression model revealed maximal bench press strength as the most significant variable for predicting total BMD in respect to the variables being measured. In addition, a negative relationship was displayed between BMD and partial curl-ups (r = -0.387) and maximal oxygen uptake (r = -0.360). CONCLUSIONS: These results indicate that the relationship between BMD and muscular strength, particularly maximal bench press strength, may be greater than previously indicated

ESTIMATION OF TOTAL BODY WATER USING SINGLE FREQUENCY BIOIMPEDANCE ANALYSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Zackary S. Cicone1, Michael V. Fedewa2, Clifton J. Holmes3, Michael R. Esco, FACSM2, Hayley V. MacDonald2. 1Shenandoah University, Winchester, VA. 2The University of Alabama, Tuscaloosa, AL. 3Washington University in St. Louis, St. Louis, MO. BACKGROUND: Single frequency bioimpedance analysis (SFBIA) is a simple alternative to isotope dilution techniques for assessing total body water (TBW). How characteristics related to the sample (e.g., age, health status) and SFBIA methodology (e.g., criterion technique, device, frequency, index) influence SFBIA accuracy has yet to be comprehensively examined. The aims of this systematic review and meta-analysis were to 1) quantify the accuracy of SFBIA for predicting TBW and 2) determine the potential impact of study-level effect modifiers. METHODS: Five electronic databases were searched for studies that compared isotope dilution TBW values to SFBIA. Standardized mean difference (SMD) effect sizes were calculated using the Gibbons method for each comparison and an overall estimate was generated using a three-level random-effects model. Within- and between-study level variance was evaluated using one-sided log-likelihood-ratio tests. When appropriate, subgroup analyses were performed to identify potential study-level moderators. RESULTS: Aggregate-level data from 51 studies (255 individual effects) were included in the final analysis. Study samples included predominantly healthy participants with large ranges in mean age (0 to 82 y) and body mass index (14.1 to 50.2 kg/m2). The overall SMD indicated a negligible difference between SFBIA and criterion dilution methods (SMD=-0.04, p=0.67), but lacked homogeneity at both the within- (σ2=0.45) and between-study (σ2=0.26) levels (all p\u3c0.001). Moderator analysis revealed that the interaction between frequency and index (p\u3c0.01) influenced the observed error between SFBIA and criterion methods. Resistance index (Ht2/R) produced less error than impedance index (Ht2/Z) across all frequencies (all p\u3e0.10), with Ht2/R at 50 kHz producing the most accurate estimate of TBW (β=0.06, p\u3e0.05). Additionally, there was a small yet significant effect for sample sex (% women, β=-0.003, p\u3c0.05), suggesting that SFBIA may underestimate TBW in samples that are predominantly women. No main effects were observed for other study-level factors (e.g., sample characteristics or BIA methodology). CONCLUSION: Overall, Ht2/R produced less error in TBW estimation than Ht2/Z, with Ht2/R at 50 kHz providing the smallest mean difference in TBW when compared to isotope dilution. These results suggest that SFBIA may provide acceptable estimates of TBW across a range of diverse samples

RELIABILITY OF BODY COMPOSITION MEASURED USING A SMARTPHONE APPLICATION AND DIFFERENT CAMERA RESOLUTIONS

Mary E. Lovelady, Casey J. Metoyer, Katherine Sullivan, Jacob Broeckel, Michael R. Esco, FACSM, Michael V. Fedewa. University Of Alabama, Tuscaloosa, AL. BACKGROUND: Many traditional laboratory methods of measuring body fat percentage (%Fat) are inaccessible to healthcare professionals due to the cost, complexity, time, and portability. Recently, a new smartphone application was developed that allows for an accurate estimate of %Fat by analyzing a single 2-dimensional digital image. Although the validity of the application has been previously examined, the reliability across different camera resolutions has not been thoroughly tested. PURPOSE: The aim of this study was to evaluate the reliability of %Fat estimates from digital images captured using devices with different megapixel cameras. METHODS: A convenience sample of adult participants was recruited for the study (n=12, 83.33% female, 83.33% Caucasian, 31.25±10.49 yrs., 69.44±11.77 kg/m2). Age, gender, and race/ethnicity were assessed via self-report. Height was measured to the nearest 0.1 cm using a stadiometer (SECA 213, Seca Ltd., Hamburg, Germany). Weight was measured to the nearest 0.1 kg using a calibrated digital scale (Tanita BWB-800, Tanita Corporation, Tokyo, Japan). A full-body digital image was taken from the posterior view, with participants standing in front of a white background, using a 12-megapixel iPhone 12 (Apple Inc., Cupertino, CA) (%Fat12mp) and an 8-megapixel iPad Air 2 (Apple Inc., Cupertino, CA) (%Fat8mp). %Fat was derived using an automated smartphone application and a proprietary algorithm (made Health and Fitness, LLC, Birmingham, AL). A paired samples t-test was used to examine potential mean differences between %Fat12mp and %Fat8mp. The reliability was also measured using Pearson’s r, and described as weak, moderate, strong, or near-perfect (r=0.2, 0.5, 0.8, or 0.9 respectively). Data are presented as mean±standard deviation, with an alpha level set to p\u3c0.05. RESULTS: No significant mean differences in %Fat were observed between %Fat12mp and %Fat8mp (26.92±4.96 %Fat and 27.16±3.08 %Fat, respectively; p=0.37). Near-perfect correlations were observed between %Fat12mp and %Fat8mp (r=0.99, p\u3c0.001). DISCUSSION: Based on the results of this study, the smartphone application provides a reliable estimate of %Fat across devices with different megapixel cameras. Future studies should explore other conditions, including different lighting, different color backgrounds, and other devices, as well as within a larger more diverse sample