Grip Strength Moderates the Association between Anthropometric and Body Composition Indicators and Liver Fat in Youth with an Excess of Adiposity

Relationship between fitness performance and a newly developed continuous body composition score in U.S. adolescent boys

OBJECTIVES

Body composition (BC) assessment typically requires the administration of a single test and can have different evaluation outcomes depending on the selected test and the specific population. The purpose of this study was twofold. Firstly, to develop and validate a novel continuous body composition (CBC) score using the continuous response model (CRM). Secondly, to examine the relationship between CBC scores and fitness performance.

METHODS

Data from the 2012 NHANES National Youth Fitness Survey (NNYFS) were used and consisted of n=212 adolescent boys 12-15 years of age. CBC scale variables included body mass (BM), body mass index (BMI), arm circumference (AC), waist circumference (WC), calf circumference (CC), calf skinfold (CSF), triceps skinfold (TSF), and subscapular skinfold (SSF). Fitness performance variables included cardiorespiratory fitness (CRF, mL/kg/min), leg strength (LS, lb), modified pull-ups (MPU, #), grip strength (GS, kg), and plank (PL, sec). Samejima's CRM, factor analysis, convergent validity coefficients and score reliability were used to validate the CBC scale. Multinomial logistic regression and multiple linear regression were used to examine the relationship between CBC scores and fitness performance variables.

RESULTS

Factor analysis of the CBC scale variables retained a single factor (loadings >0.81, 88% explained variance) with strong internal consistency (α=0.96). The CRM analysis indicated all CBC scale variables fit a unidimensional construct with adequate discrimination (as: 0.71-2.16) and difficulty (bs: -0.04-1.44). CBC scores (Mean=0, SD=1.00) displayed strong reliability (SEE.θ=0.22, r.θ=0.95) with lower values representing smaller-more-lean individuals and higher values representing larger-less-lean individuals. All fully adjusted regression models showed significant (ps<0.05) negative relationships between CBC scores and CRF, MPU, and PL and positive relationships between CBC scores and LS and GS.

CONCLUSION

The CRM-derived CBC score is a novel measure of BC and found to be positively associated with strength performance and negatively associated with endurance performance in U.S. adolescent boys.

Low handgrip strength is associated with higher liver enzyme concentrations in US adolescents

BACKGROUND

Increasing evidence highlights the role of muscular strength as a protective factor for cardiometabolic health in adolescents. However, it is not known the relationship between liver enzyme concentrations, liver disease risk factors, and muscular strength among young populations. The aim of this study was to determine the association between muscle strength and liver enzymes and chronic liver disease risk among US adolescents.

METHODS

Data from the NHANES cross-sectional study (2011-2014) was used. A total of 1270 adolescents were included in the final analysis (12-17 years old). Absolute handgrip strength (kg) was normalized according to body composition parameters by body weight [NHSw], whole-body fat [NHSf], and trunk fat [NHSt]).

RESULTS

In boys, handgrip strength was inversely associated with higher values of aspartate aminotransferase (AST) and gamma glutamyl transpeptidase (GGT) for all estimations of muscle strength (NHSw, NHSf, and NHSt) (p < 0.050). Likewise, boys with high and intermediate NHSw, NHSf, and NHSt presented lower AST and GGT than their counterparts with low handgrip strength (p < 0.050).

CONCLUSIONS

Our findings highlight the importance of muscular strength during adolescence since they could help in developing better liver enzyme profiles among adolescent population.

IMPACT

Our research suggests that US adolescents with low handgrip strength have higher values of liver enzymes as well as a higher prevalence of chronic liver disease. These findings are clinically meaningful and highlight the importance of muscular strength during adolescence since they could help in developing better liver enzyme profiles among young populations.

Grip power test: A new valid and reliable method for assessing muscle power in healthy adolescents

The assessment of the strength and muscle mass of the hand-finger segment are reliable indicators of health and predictors of cardiometabolic risk in the adult population. However, there are no valid and reliable tests to assess the muscle power of this segment in healthy adolescents. The objective of this study was to determine the validity and inter-day reliability of a grip power test (Grip_W test) in healthy adolescents. Twenty-one adolescents (15.61 ± 2.20 years old) were part of the study. All participants were instructed to perform a grip with incremental load sets from 1–10 kg as fast as possible. The validity of the Grip_W test was determined with the load-power curve and linear regression equation. Inter-day reliability considered the coefficient of variation (CV), intra-class correlation coefficient (ICC), and standard error of the mean (SEM). The significance level for all statistical analyses was p < 0.05. The parabola in the load-power curve for both hands showed normality for the Grip_W test. In addition, the analysis showed a CV = 4.63% and ICC = 1.00 for the right hand, while the left hand showed a CV = 3.23% and ICC = 1.00. The Grip_W test proved to be valid and reliable for assessing gripping muscle power functionally and unilaterally in healthy adolescents.

Relationship between triglyceride glucose index and the incidence of non-alcoholic fatty liver disease in the elderly: a retrospective cohort study in China

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is one of the major causes of liver-related diseases but relationship between triglyceride glucose (TyG) and NAFLD in the elderly is not reported yet. In this study, we investigated the role of TyG index for predicting the incidence of NAFLD in the elderly.

DESIGN AND SETTING

This is a prospective cohort study in Henan, China, from 2011 to 2018.

PARTICIPANTS AND METHODS

In total, 46 693 elderly who participated in a routine physical examination programme from 2011 to 2018 were included in this study. TyG index was calculated as ln (fasting triglyceride (mg/dL)×fasting plasma glucose (mg/dL)/2), while NAFLD was defined as hepatic steatosis after excluding other causes based on the results of abdominal ultrasonography; Cox regression model was performed to explore the relationship between TyG index and NAFLD. Also, mediation effect was used to analyse the role of the TyG index in WHtR (waist-to-height ratio) and NAFLD.

RESULTS

During the 149 041 person-years follow-up, a total of 5660 NAFLD events occurred (3.80/100 person-years). After adjusting for potential confounding factors, quartiles 4 of TyG index significantly increased the incidence of NAFLD compared with quartile 1, the HRs and 95% CI were 1.314 (1.234 to 1.457). In addition, TyG index played a partial mediating role in the relationship between WHtR and NAFLD and indirect effect was 1.009 (1.006 to 1.011).

CONCLUSION

Higher TyG index was associated with higher risk of NAFLD in the aged, and therefore, TyG index may be a novel predictor for incidence of NAFLD. Further, regular examination and evaluation of the TyG index might be useful for controlling the occurrence of NAFLD.

Association between Cardiorespiratory Fitness, Relative Grip Strength with Non-Alcoholic Fatty Liver Disease

BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is a common clinical syndrome with no medications for long-term management. At present, diet control and weight loss are 2 major lifestyle components to reduce the risk of NAFLD. However, other lifestyle components such as cardiorespiratory fitness (CRF) and grip strength (GS) have been neglected in research. This study was to investigate the correlation between CRF, relative GS (RGS), and NAFLD among a male study population. MATERIAL AND METHODS We screened 1126 men who underwent comprehensive health checks. The participants were divided into an NAFLD group (n=224) and a non-NAFLD group (n=902). The clinical data analyzed included anthropometry, biochemical examination, CRF measurement, and GS calculation were recorded, and the dose-response association between maximal oxygen uptake (VO₂max), RGS, and NAFLD. Stepwise logistic regression analysis was conducted to establish a predictive model of NAFLD. RESULTS VO₂max <30 mL/kg⁻¹·min⁻¹ was not associated with the risk of NAFLD (P>0.05). When VO₂max was >30 mL/kg⁻¹·min⁻¹, the risk of NAFLD decreased obviously (P=0.007), suggesting a dose-response relationship between VO₂max and NAFLD risk. With the increase of RGS, the risk of NAFLD decreased prominently (P<0.001), which indicated a dose-response relationship between RGS and NAFLD risk. We also found that body fat percentage, body mass index, systolic blood pressure, diastolic blood pressure, total cholesterol and triglycerides were risk factors, whereas VO₂max >30 mL/kg⁻¹·min⁻¹, RGS, and high-density lipoprotein cholesterol were protective factors for NAFLD. The area under the curve (AUC) of the predictive model of NAFLD was 0.819 (95% confidence interval [CI]: 0.790-0.847, P=0.174). The sensitivity and specificity were 80.4% and 67.8%, respectively. CONCLUSIONS In the male study population, VO₂max and RGS were negatively correlated with the risk of NAFLD, thus, the risk of NAFLD could thus be reduced by improving VO₂max and RGS in this population.

Moderation Effect of Handgrip Strength on the Associations of Obesity and Metabolic Syndrome With Fatty Liver in Adolescents

INTRODUCTION/BACKGROUND

This study aimed to evaluate the effect of handgrip strength on the associations of body mass index and metabolic syndrome with an indicator of nonalcoholic fatty liver disease in adolescents.

METHODOLOGY

In data of 1690 adolescents aged 10-18 yr from the Korea National Health and Nutrition Examination Survey 2014-2016, alanine amino-transferase levels, age, sex, bodyweight-, sex-, and age-standardized handgrip strength, age- and sex-specific body mass index Z-scores, and metabolic syndrome severity scores were assessed. Nonalcoholic fatty liver disease was defined based on alanine amino-transferase levels (boys ≥52U/L, girls ≥44U/L) in adolescents who were overweight. Moderation analysis via the PROCESS procedure was performed.

RESULTS

The prevalence of nonalcoholic fatty liver disease was 1.5% among all adolescents and 6.7% among those who were overweight. In all adolescents and adolescents who were overweight, age- and sex-specific body mass index Z-scores and metabolic syndrome scores had positive associations with nonalcoholic fatty liver disease after adjusting for bodyweight-, sex-, and age-standardized handgrip strength. Bodyweight-, sex-, and age-standardized handgrip strength had an inverse association with nonalcoholic fatty liver disease after adjusting for metabolic syndrome scores, and this association became nonsignificant after adjusting for age- and sex-specific body mass index Z-scores. There were positive associations between age- and sex-specific body mass index Z-scores and alanine amino-transferase levels when bodyweight-, sex-, and age-standardized handgrip strength values were ≤-0.13 in overweight adolescents and ≤0.74 in all adolescents, whereas these associations were nonsignificant or negative above those cut-off values. These cut-off values of bodyweight-, sex-, and age-standardized handgrip strength for the relationship between metabolic syndrome scores and alanine amino-transferase levels were -0.15 in overweight adolescents and 0.55 in all adolescents.

CONCLUSIONS

A higher bodyweight-, sex-, and age-standardized handgrip strength may attenuate the risk of obesity and metabolic syndrome for an indicator of nonalcoholic fatty liver disease in adolescents.

Muscle mass to visceral fat ratio is an important predictor of the metabolic syndrome in college students

This study aimed to evaluate the associations between the muscle mass to visceral fat (MVF) ratio and cardiometabolic risk factors in a large population of college students in Colombia and to propose cut-off points of this index for the metabolic syndrome (MetS). A total of 1464 young adults recruited from the FUPRECOL (Asociación de la Fuerza Prensil con Manifestaciones Tempranas de Riesgo Cardiovascular en Jóvenes y Adultos Colombianos) study were categorised into four groups based on their MVF ratio. Muscle mass and visceral fat level of the participants were measured using a bioelectrical impedance analysis. Cardiometabolic risk factors including lifestyle characteristics, anthropometry, blood pressure and biochemical parameters were assessed. The prevalence of moderate to severe obesity, hypertension and the MetS was higher in subjects in quartile (Q)1 (lower MVF ratio) (P <0·001). ANCOVA revealed that the subjects in Q1 had higher cardiometabolic disturbances, including altered anthropometry, blood pressure, muscle strength and biochemical parameters after adjusting for age and sex compared with young adults in higher MVF ratio quartiles (P <0·001). Muscular mass and physical activity levels were significantly lower in subjects with a lower MVF ratio (P <0·001). The receiver operating characteristic curve analyses indicated that in men the best MVF ratio cut-off point for detecting the MetS was 18·0 (AUC 0·83, sensitivity 78 % and specificity 77 %) and for women, the MVF ratio cut-off point was 13·7 (AUC 0·85, sensitivity 76 % and specificity 87 %). A lower MVF ratio is associated with a higher risk cardiometabolic profile in early adulthood, supporting that the MVF ratio could be used as a complementary screening tool that may help clinicians identify young adults at high cardiometabolic risk.

Liver Fat Content and Body Fat Distribution in Youths with Excess Adiposity

This study had two main objectives: To examine the association between body fat distribution and non-alcoholic fatty liver disease (NAFLD) and liver fat content, and to determine whether the relationship between NAFLD and regional body fat distribution, with respect to liver fat content in youths with excess adiposity, is independent of cardiorespiratory fitness (CRF) and a healthy diet. Liver fat content (controlled attenuation parameter (CAP)), body fat distribution (body mass index (BMI) z-score, waist circumference, waist-to-height ratio, fat mass/height, body fat percentage, total fat mass, android-to-gynoid fat mass ratio, visceral adipose tissue (VAT), and lean mass index, determined by dual-energy X-ray absorptiometry (DXA)), CRF (20-m shuttle-run test), and healthy diet (adherence to the Mediterranean diet by KIDMED questionnaire) were measured in 126 adolescents (66% girls) aged between 11 and 17 years. Participants were assigned to two groups according to the presence or absence of hepatic steatosis (CAP values ≥225 dB/m or <225 dB/m of liver fat, respectively). Considering the similar total fat values for the two groups (>30% by DXA), youths with NAFLD had higher fat distribution parameters than those without NAFLD, regardless of sex, age, puberty stage, lean mass index, CRF, and healthy diet (p < 0.01). In the non-NAFLD group, the association between hepatic fat and fat distribution parameters presented a similar pattern, although the association was statistically insignificant after adjusting for a potential confounding variable (ps > 0.05), except for the case of VAT. Body fat distribution parameters were higher in youths with NAFLD compared to those without NAFLD. Additionally, body fat distribution showed a significant association with liver fat content as assessed by CAP in youths with NAFLD independent of CRF and adherence to the Mediterranean diet, supporting the notion that upper body fat distribution might play a pivotal role in the development of NAFLD in adolescents. These results may have implications for the clinical management of youths with excess adiposity given the high prevalence of NAFLD in children and young adults.