Reference growth curves to identify weight status (underweight, overweight or obesity) in children and adolescents: systematic review.

The identification of somatic growth, through reference curves, can be used to create strategies and public policies to reduce public health problems such as malnutrition and obesity and to identify underweight, overweight and obesity. The purpose of this systematic review was to identify studies providing reference growth curves for weight status in children and adolescents. A systematic search was conducted in eight databases and in gray literature (Google scholar). To assess the risk of bias/methodological quality of studies, the National Institutes of Health (NIH) Quality Assessment Tool for Observational Cohort and Cross-sectional Studies (NHLBI) was used. Overall, 86 studies that met the inclusion criteria were included. Through the values   of reference growth curves for the identification of underweight, overweight and obesity, it was possible to verify that there is great variability among percentiles for the identification of underweight, overweight and obesity. The most prevalent percentiles for underweight were P3 and P5; for overweight, the most prevalent was P85 and the most prevalent percentiles for obesity were P95 and P97. The most prevalent anthropometric indicators were Body Mass Index (BMI), Waist Circumference (WC), Body Mass (BM) for age and height for age. Conclusion: Such data can demonstrate that the optimal growth must be reached, through the standard growth curves, but that the reference curves demonstrate a cut of the population growth, raising possible variables that can influence the optimal growth, such as an increase in the practice of physical activities and an awareness of proper nutrition.

Regional phase angle, not whole-body, is augmented in response to pre-season in professional soccer players.

The objective of this article was to assess the effects of six-week pre-season training on whole-body and regional bioelectrical impedance analysis (BIA)-derived parameters, body composition, power, and aerobic performance in professional soccer players. Ten professional soccer athletes participated in the present study. Whole-body and regional hamstrings BIA-derived parameters [resistance, reactance, impedance, phase angle (PhA)], body composition, total body water (TBW), intracellular (ICW), and extracellular (ECW) were measured before, at mid-point, and after sixth week of the pre-season. Power (countermovement jump and squat jump) and aerobic capacity (Yo-Yo test) were measured before and after pre-season. There was a significant increase in the regional PhA (+13.9%) but not in the whole-body. There was a reduction in fat mass (-4.1%), an increase in fat-free mass (+1.7%), TBW (+8.3%), ICW (+8.8%), and ECW (+7.6%), as well as an increase in jump height (+11.0%) and distance covered in the Yo-Yo test (+34.7%). From our results, it is possible to suggest that pre-season training can induce an increase in hamstring PhA as well as body recomposition and improvement of physical fitness in professional soccer players.

Association Between Body Fat Distribution Assessed by Different Techniques and Body Image Perception in HIV-Infected Children and Adolescents.

PURPOSE: verify whether there is difference in body fat values assessed by different methods according to the body image perception of HIV-infected children and adolescents. DESIGN AND METHODS: This is a cross-sectional study with 65 HIV-infected children and adolescents (aged 8-15 years). Total fat mass, trunk fat mass, arm fat mass and leg fat mass were obtained through dual-energy X-ray absorptiometry (DXA). Anthropometric variables were measured according to international standardization. Body image was assessed using a scale of body silhouettes. Bone age covariates were assessed using carpal wrist X-rays and physical activity by accelerometers. Information regarding viral load and use of combined antiretroviral therapy was obtained from medical records. In males, no significant difference in body fat values and body image categories was observed. RESULTS: In the model with covariates, girls who desired to reduce body weight had higher BMI (18.96 kg / m2 ± 2.47, R2 adj: 0.613), total fat mass (14.25 kg ± 1.37, R2 adj: 0.589), trunk fat mass (6.50 kg ± 0.66, R2 adj: 0.611) and leg fat mass values (6.01Kg ± 0.57, R2 adj: 0.503) in comparison to girls who were satisfied and to those who desired to increase body weight. CONCLUSIONS: HIV + girls who desired to reduce body weight had greater amount of BMI, total fat mass, trunk fat mass and leg fat mass compared to those who were satisfied and those who desired to increase body weight. PRACTICE IMPLICATIONS: These data can be used to assist in the process of coping and accepting body image.

Phase angle is associated with the physical fitness of HIV-infected children and adolescents.

The objective of this study was to identify the association of phase angle with physical fitness in children and adolescents infected with HIV. Sixty-four children and adolescents infected with HIV (8-15 years old) were tested for vertical transmission. The electrical bioimpedance was used to obtain the phase angle. Body fat (BF) and lean soft tissue mass (LSTM) were measured by x-ray absorptiometry, and the manual grip strength was evaluated by dynamometry. The peak oxygen consumption (VO2 peak) was measured by respiratory change in a submaximal incremental test. Moderate-vigorous physical activity (MVP) and sedentary behavior were measured using accelerometers and were used as covariates. Multiple linear regression was used. The linear correlation analyses demonstrated that the phase angle was inversely proportional to relative BF (r = -0.26), but was not associated with absolute body fat (r = -0.02). The phase angle was directly associated with LSTM (r = 0.57), handgrip strength, and (r = 0.43) peak VO2 (r = 0.55). The phase angle was not associated with absolute BF (ß = -0.017, P = 0.413) and relative (ß = -0.014, P = 0.175). The phase angle presented a direct association with LSTM (ß = 0.041, P = 0.019) and peak VO2 (ß = 0.005; P = 0.019), regardless of age, sex, sexual maturation, MVPA, sedentary behavior, antiretroviral drugs, and viral load. No association was found between phase angle and handgrip strength (ß = 0.153; P = 0.199). It was concluded that phase angle was associated with LSTM and the aerobic fitness in HIV-infected children and adolescents.

Utilization of bioelectrical impedance vector analysis (BIVA) in children and adolescents without diagnosed diseases: a systematic review.

Introduction. Bioelectrical impedance vector analysis (BIVA) emerges as a technique that utilizes raw parameters of bioelectrical impedance analysis and assumes the use of a reference population for information analysis.Objective. To summarize the reference values, main studies objectives, approaches, pre-test recommendations and technical characteristics of the devices employed in studies utilizing BIVA among children and adolescents without diagnosed diseases.Methods. A systematic search was conducted in nine electronic databases (CINAHL, LILACS, PubMed, SciELO, Scopus, SPORTDiscus, Science Direct, MEDLINE, and Web of Science). Studies with different designs which allowed extracting information regarding reference values of BIVA in children and adolescents without diagnosed diseases, aged 19 years or younger, were included. The systematic review followed PRISMA procedures and was registered in PROSPERO (registration: CRD42023391069).Results. After applying the eligibility criteria, 36 studies were included. Twenty studies (55.6%) analyzed body composition using BIVA, thirteen studies (36.1%) aimed to establish reference values for BIVA, and three studies (8.3%) investigated the association of physical performance with BIVA. There was heterogeneity regarding the reference populations employed by the studies. Fifteen studies used their own sample as a reference (41.6%), four studies used the adult population as a reference (11.1%), and five studies used reference values from athletes (13.9%).Conclusion. Nutricional status and body composition were the main studies objectives. References values were not always adequate or specific for the sample and population. Furthermore, there was no pattern of pre-test recommendations among the studies.

Phase angle and body composition: A scoping review.

The aim of the study was to map evidence on the association between phase angle (PhA) and body composition in populations healthy and clinical populations). A systematic search for information regarding the topic was conducted in nine electronic databases (CINAHL, LILACS, PubMed, SciELO, Scopus, SPORTDiscus, Science Direct, MEDLINE and Web of Science) between October and November 2021. Studies with different designs, which allowed extracting information about the relationship between PhA and body composition (body cell mass [BCM], muscle tissue, bone mineral content, lean mass, total fat mass, visceral fat, and lean soft tissue mass [LSTM]) were included. Of the total of 11,913 initially identified studies, 59 were included after reading titles, abstracts, full texts and references. Most studies (40.67%; n = 24) presented data from Brazilian samples. With regard to the design of studies, 15 (25.42%) had longitudinal design. The age group of studies was wide, with studies involved 3-year-old children and 88-year-old adults. Body fat mass was evaluated by 31 studies (52.54%) in which 11 observed inverse relationships, nine studies showed direct relationships and 11 observed no relationship. Regarding lean mass, muscle mass, and fat-free mass components, most studies observed direct relationship with PhA (n = 37; 86.04%). It could be concluded that the phase angle was directly associated with lean mass and muscle mass in different age groups (children, adolescents, adults and older adults) and in people with different health diagnoses (HIV, cancer, hemodialysis, sarcopenia and without the diagnosis of diseases). Regarding body fat and the other investigated components, there is not enough evidence to establish the direction of associations.

Association between Phase Angle and Body Composition of Children and Adolescents Diagnosed with HIV Infection.

The aim of the study was to investigate how phase angle (PhA) is associated with subtotal and lumbar spine bone mineral density [BMD], lean soft tissue mass [LSTM], total body fat mass, android and gynoid in children and adolescents with HIV according to sex. A cross-sectional study was conducted in Florianópolis, Brazil, involving 64 children and adolescents vertically transmitted with HIV. Resistance and reactance values were obtained using bioelectrical impedance analysis, and PhA was subsequently calculated. Dual emission X-ray absorptiometry was used to assess body composition. Antiretroviral medication, physical activity (accelerometers) and skeletal maturation (wrist-carpal radiography) were used in the adjusted model. In males, PhA was directly associated with subtotal BMD (ßadj: 0.65; R²: 0.38, p < 0.01) and lumbar spine BMD (ßadj: 0.53; R²: 0.22, p = 0.01), directly associated with LSTM (ßadj: 0.76; R²: 0.46, p < 0.01), and inversely associated with gynoid fat (ßadj: -0.47; R²: 0.2, p = 0.01), in adjusted models. In females, PhA was directly associated with subtotal BMD (ßadj: 0.46; R²: 0.17, p < 0.01) and lumbar spine BMD (ßadj: 0.48; R²: 0.19, p < 0.01). It is concluded that PhA was directly associated with subtotal and regional BMD, LSTM, and inversely with gynoid fat in boys with HIV. In girls, PA was directly associated only with subtotal and regional BMD.

Association between lipid and glycemic profile and total body and trunk fat in children and adolescents diagnosed with HIV.

INTRODUCTION: Metabolic alterations and body fat redistribution are common in people living with HIV using antiretroviral therapy and increase the risk of premature cardiovascular diseases. AIM: To verify the presence of difference in the lipid and glycemic profile in relation to different total body and trunk fat phenotypes in children and adolescents diagnosed with HIV+. METHOD: This is a cross-sectional study carried out with 62 children and adolescents diagnosed with HIV+. Lipid and glycemic profiles were obtained from blood samples. Total and trunk fat mass (FM) was obtained by DXA. Analysis of covariance was used to verify if there is difference in the lipid and glycemic profile between total body and trunk fat phenotypes. RESULTS: In males, in the covariate-adjusted model, it was observed that boys with high total FM had higher triglyceride values (mean: 164.9 mg/dl-1 ±31.2) compared to those with low and adequate total FM. In females, in adjusted models, it was observed that girls with high total FM had higher total cholesterol (mean: 181.6 mg/dl-1 ±13.8) and LDL-C values (mean: 111.8 mg/dl-1 ±12.0), compared to those with low and adequate total FM. Girls with trunk FM had higher total cholesterol (mean: 181.6 mg/dl-1 ± 13.8), LDL-C (mean: 71.3 mg/dl-1 ± 9.6) and blood glucose values (91.6 mg/dl-1 ± 2.2). CONCLUSION: Boys with high total FM had higher triglyceride levels, while in females, it was observed that girls with high total FM and high trunk FM had higher total cholesterol, LDL-C and blood glucose values. High body fat in children and adolescents living with HIV is related to metabolic changes in the lipid and glycemic profile, with specificities of sex and fat location.

Does antiretroviral therapy change the relationship between body composition and muscle strength in children and adolescents diagnosed with HIV?

Background: HIV infection and prolonged use of antiretroviral therapy (ART) can impact the body composition and muscle strength of HIV-infected children and adolescents. Therefore, the aim was to verify the association between lean soft tissue mass (LSTM) and handgrip strength (HGS) in children and adolescents diagnosed with HIV using or not using ART (with or without protease inhibitors [PI]).Method: Cross-sectional study with 65 children and adolescents diagnosed with HIV aged 8-15 years of both sexes. LSTM was obtained through dual X-ray absorptiometry (DXA) and HGS using hydraulic dynamometer. Information on viral load, CD4+ T lymphocytes and type of ART (with or without [PI]) were obtained from medical records. Simple and multiple linear regression (adjusted for viral load and CD4+ T lymphocytes) was used, with p < 0.05.Results: For children and adolescents diagnosed with HIV using ART without PI, the model (LSTM, viral load and CD4+ T lymphocytes) explained 68% of HGS variability. For group with ART and PI, the model explained 73%. For group that did not use ART, the model was not associated with HGS.Conclusion: The magnitude of the association between LSTM and HGS was greater than in children and adolescents using ART with PI. ImpactIt is recognized that in the long-term antiretroviral drugs can negatively impact the body composition of children and adolescents diagnosed with HIV. However, few studies have investigated the short-term impact of drug use.The use of antiretroviral therapy (ART) with protease inhibitor (PI) increased the explanatory power of lean soft tissue mass with muscle strength in children and adolescents diagnosed with HIV.These results demonstrate the importance of antiretroviral drugs in the short term. Further studies are needed to identify how and when interventions are needed to reduce the negative effects of drugs in the long term.

Muscle mass indicators as fat-free mass and lean soft tissue mass are associated with handgrip strength in HIV-diagnosed children and adolescents.

OBJECTIVE: To verify the association between fat free mass (FFM) and lean soft tissue mass (LSTM) with handgrip strength (HGS) in HIV children and adolescents, according to sex. METHOD: This cross-sectional study included 65 HIV children and adolescents, aged from 8-15 years (30 boys and 35 girls). FFM and LSTM were measured by dual-energy X-ray absorptiometry (DXA). HGS was measured with hydraulic dynamometer. Bone age was assessed by radiography of the wrist of the left carpus and moderate to vigorous physical activity was obtained through the use of accelerometers. The use of antiretroviral drugs (ART) was obtained from the medical records of each participant. RESULTS: For boys, the FFM model explained 86% the HGS variability (p < 0.001). For girls, the FFM model explained 90% the HGS variability (p < 0.001). LSTM explained 88% the HGS variability for both sexes. CONCLUSION: FFM and LSTM were directly associated with HGS. However, models with bone age, physical activity level and type of ART improved the explanatory power of LLM and LSTM in HGS.

What anthropometric indicators are associated with insulin resistance? Cross-sectional study on children and adolescents with diagnosed human immunodeficiency virus.

BACKGROUND: Studies that test associations between anthropometric indicators and insulin resistance (IR) need to provide better evidence in the context of the pediatric population (children and adolescents) with human immunodeficiency virus (HIV), as anthropometric indicators present a better explanation of the distribution of body fat. OBJECTIVE: To test the associations between anthropometric indicators and insulin resistance (IR) among children and adolescents diagnosed with HIV. DESIGN AND SETTING: Cross-sectional study on 65 children and adolescents (8-15 years) infected with HIV through vertical transmission conducted at the Joana de Gusmão Children's Hospital, Florianópolis, Brazil. METHODS: The anthropometric indicators measured were the abdominal (ASF), triceps (TSF), subscapular (SSF) and calf (CSF) skinfolds. The relaxed arm (RAC), waist (WC) and neck (NC) circumferences were also measured. Body mass index (BMI) was calculated from the relationship between body mass and height. IR was calculated through the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR). Simple and multiple linear regression analyses were used. RESULTS: After adjustment for covariates (sex, bone age, CD4+ T lymphocytes, CD8+ T lymphocytes, viral load, and physical activity), associations between IR and models with SSF and CSF remained. Each of these explained 20% of IR variability. For females, in the adjusted analyses, direct associations between IR and models with ASF (R² = 0.26) and TSF (R² = 0.31) were observed. CONCLUSIONS: SSF and CSF in males and ASF and TSF in females were associated with IR in HIV-infected children and adolescents.

Muscular Fitness and Cardiometabolic Variables in Children and Adolescents: A Systematic Review.

BACKGROUND: The importance of muscular fitness (MF) in the performance of activities of daily living is unequivocal. Additionally, emerging evidence has shown MF can reduce cardiometabolic risk in children and adolescents. OBJECTIVES: The purpose of this study was to examine and summarize the evidence regarding the relationship between MF phenotypes (i.e., maximum muscular strength/power, muscular endurance, and maximum muscular strength/power/endurance) and cardiometabolic variables (obesity, blood pressure, lipids, glucose homeostasis, inflammatory markers, and clustered cardiometabolic variables) in children and adolescents. DESIGN: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and was registered with PROSPERO, number CRD42020179273. DATA SOURCES: A systematic review was performed on five databases (PubMed, EMBASE, SciELO, Scopus, and Web of Knowledge) from database inception to May 2020, with complementary searches in reference lists. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eligibility criteria included (1) a study sample of youth aged ≤ 19 years, (2) an assessment of MF with individual or clustered cardiometabolic variables derived from adjusted models (regardless of test/measurement adopted or direction of reported association), and (3) a report of the association between both, using observational studies. Only original articles published in peer-reviewed journals in English, Portuguese, and Spanish languages were considered. The quality of the included studies was assessed by using the National Heart, Lung, and Blood Institute checklist. The percentage of results reporting a statistically significant inverse association between each MF phenotype and cardiometabolic variables was calculated. RESULTS: Of the 23,686 articles initially identified, 96 were included (77 cross-sectional and 19 longitudinal), with data from children and adolescents from 35 countries. The score for the quality of evidence ranged from 0.33 to 0.92 (1.00 maximum). MF assessed by maximum muscular strength/power was inversely associated with lower obesity (64/113 total results (56.6%)) and reduction in clustered cardiometabolic risk (28/48 total results (58.3%)). When assessed by muscular endurance, an inverse association with obesity (30/44 total results (68.1%)) and cardiometabolic risk (5/8 total results (62.5%)) was identified. Most of the results for the relationship between MF phenotypes with blood pressure, lipids, glucose homeostasis, and inflammatory markers indicated a paucity of evidence for these interrelationships (percentage of results below 50.0%). CONCLUSION: MF assessed by maximum muscular strength/power or muscular endurance is potentially associated with lower obesity and lower risk related to clustered cardiometabolic variables in children and adolescents. There is limited support for an inverse association between MF with blood pressure, lipids, glucose homeostasis biomarkers, and inflammatory markers in children and adolescents.

Association between bone mineral density and content and physical growth parameters among children and adolescents diagnosed with HIV: a cross-sectional study.

BACKGROUND: During childhood and adolescence, there are significant increases in bone mineral content (BMC) and bone mineral density (BMD). OBJECTIVE: To investigate physical growth parameters associated with BMD and BMC among children and adolescents diagnosed with human immunodeficiency virus (HIV). DESIGN AND SETTING: Cross-sectional study conducted in Florianópolis, Brazil, among 63 children and adolescents (aged 8-15 years) diagnosed with HIV. METHOD: BMD, BMC and fat percentage z score were evaluated using dual X-ray absorptiometry. Age/height z score and body mass index (BMI)/age z score were obtained in accordance with international recommendations, and bone age was obtained through hand-wrist radiography. Sex, family income, information on HIV infection (T CD4+ lymphocyte count, viral load and type of antiretroviral therapy, moderate-vigorous physical activity and sedentary behavior) were used as adjustment variables in the analyses. Simple and multiple linear regression analyses were performed, with a significance level of P ≤ 0.05. RESULTS: Subtotal BMD (without the head region) was directly associated with bone age, BMI/age z score and fat percentage z score, even after adjusting for covariates. Subtotal BMC/height was directly associated with bone age, height/age z score, BMI/age z score and fat percentage z score, even after adjusting for covariates. CONCLUSION: Subtotal BMD and subtotal BMC/height were directly associated with physical growth indicators among children and adolescents diagnosed with HIV.

Bioelectrical impedance vector analysis (BIVA) in university athletes.

BACKGROUND: Bioelectrical impedance vector analysis (BIVA) is able to identify differences in hydration status and body composition components, such as body cell mass (BCM) by means of plotting individuals in ellipses, when comparing groups with different characteristics. OBJECTIVE: Compare the confidence and tolerance ellipses of BIVA in individual and team sports athletes with a non-athlete reference population. DESIGN AND PARTICIPANTS: One hundred sixty-seven college athletes (team sports: 117 athletes, individual sports: 50 athletes) aged between 18 and 35 years. Bioelectrical impedance was used to measure resistance (R) and reactance (Xc) values that were used in the BIVA analysis to identify hydration status and BCM, respectively. Hotelling's t-test was used to identify differences between groups in the confidence ellipses and the comparison was made with a non-athlete Italian reference population. RESULTS: There were no differences between male team sports and individual athletes (p = 0.151) and for female athletes (p = 0.624). Most athletes were located in the 50% tolerance ellipses, indicating adequate hydration. Compared to the Italian a non-athlete population, athletes of both sexes presented left impedance vector deviation in the minor axis (Xc) of the tolerance ellipses, indicating higher BCM. CONCLUSION: There were no differences in BIVA between team and individual sports athletes, but most athletes presented an adequate hydration state and, compared to a non-athlete population, the athletes of the present study presented higher BCM.

How is the phase angle associated with total and regional bone mineral density in university athletes?

Objective.To investigate how phase angle (PhA) is associated with total and regional bone mineral density (BMD) (femur and lumbar spine) in university athletes.Approach.This cross-sectional study was conducted in Florianópolis, Brazil, with 167 university athletes from different sports (92 males). The PhA was obtained through electrical bioimpedance and BMD was obtained through dual x-ray absorptiometry (DXA). Data on the covariables age, time involved in the sport, type of sport (low, medium and high impact), daily use of oral contraceptives, and vitamin D calcium and/or protein supplementation were obtained through anamnesis, while fat mass and fat- and bone-free mass were obtained through DXA. Simple linear regression and a 5% significance level were used.Main results. In female athletes, PhA was directly associated with total BMD (ß: 2.20; 95% CI: 0.43; 3.96) and BMD in the femur (ß0.85; 95% CI: -0.23; 1.94) and lumbar spine (ß: 1.45; 95% CI: 0.44; 2.46), even after adjusting for the covariates. In male athletes, although PhA was directly associated with regional BMD (femur [ß: 0.63; 95% CI: 0.04; 1.22] and lumbar spine [ß: 0.64; 95% CI: -0.01; 1.31]) in simple linear regression, this association disappeared when the covariates were added.Significance. PhA was directly associated with total BMD and lumbar spine in female, but not male, athletes.

Phase angle association with metabolic profile in adults: A population-based study.

OBJECTIVE: This study assesses the association of the phase angle (PhA) with the metabolic profile in adults of both sexes. METHODS: This is a cross-sectional, population-based study including 949 adults 20 to 59 y of age living in the Viçosa, Minas Gerais, Brazil - urban zone. The PhA was measured based on electrical bioimpedance analysis. The metabolic profile comprised the following components: waist circumference, glucose, high-density lipoprotein cholesterol (HDL-C), non-HDL-C, triglycerides, C-reactive protein, homeostatic model assessment index-insulin resistance (HOMA-IR), serum uric acid, systolic blood pressure, and diastolic blood pressure. Linear regression models (crude and adjusted) were used to determine the association between each independent and dependent variable; statistical significance was analyzed at 5%. RESULTS: Multiple analyses showed that the increase in the values of waist circumference (ß: -0.01; 95%CI: -0.03; -0.01) represented lower values in the PhA. For the glucose, non-HDL-C, triglycerides, CRP, HOMA-IR and uric acid there was no association with PhA in the adjusted models. . CONCLUSION: Low PhA was directly associated with grater values of the waist circumference, even after adjustments were made in the sociodemographic, lifestyle variables and body mass index; this outcome suggests that PhA is a promising cardiometabolic profile biomarker in adults.

Muscular strength and cardiovascular risk factors in adults: a systematic review.

OBJECTIVE: The purpose of this study was to identify and summarize the relationships between MS and individual components of metabolic syndrome (MetS) [high waist circumference (WC), high blood pressure (BP), high systolic blood pressure (SBP), high diastolic blood pressure (DBP), high triglycerides (TG), fasting blood glucose (GL) and low HDL cholesterol levels (HDL-C)] in adults. METHODS: A systematic review was performed on six electronic databases (Lilacs, Pubmed, Scielo, Scopus, Sportdiscus, and Web of Knowledge), with complimentary searches in reference lists. The databases were investigated without restrictions regarding the period of publication. RESULTS: Of the 6,833 articles initially identified, 17 were included, with data on 43,343 adults. Higher MS values were associated with lower WC values. Different results in relation to the association between MS and BP, MS and SBP, and MS and DBP were verified. In addition, inconclusive results were verified in the relationship between MS and TG, MS and HDL-C, and MS and GL. CONCLUSION: Higher MS values were related with lower WC in adults. More evidence from longitudinal studies with high methodological rigor is needed to elucidate the relationship between MS and CVD among adults.

Association between handgrip strength and bone mass parameters in HIV-infected children and adolescents. A cross-sectional study.

BACKGROUND: Low bone mineral content (BMC) and bone mineral density (BMD) have been identified in human immunodeficiency virus (HIV)-infected children and adolescents. The direct adverse effects of HIV infection and combined antiretroviral therapy (ART) negatively contribute to bone metabolism. A direct relationship between muscle strength levels and BMD in HIV-infected adults and older adults has been described. However, it is unknown whether handgrip strength (HGS) is associated with bone mass in pediatric populations diagnosed with HIV. OBJECTIVE: To ascertain whether HGS levels are associated with BMC and BMD in HIV-infected children and adolescents. DESIGN AND SETTING: Cross-sectional study conducted in Florianãpolis, Brazil, in 2016. METHODS: The subjects were 65 children and adolescents (8-15 years) diagnosed with vertically-transmitted HIV. Subtotal and lumbar-spine BMC and BMD were obtained via dual-emission X-ray absorptiometry (DXA). HGS was measured using manual dynamometers. The covariates of sex, ART, CD4+ T lymphocytes and viral load were obtained through questionnaires and medical records. Sexual maturation was self-reported and physical activity was measured using accelerometers. Simple and multiple linear regression were used, with P < 0.05. RESULTS: HGS was directly associated with subtotal BMD (ß = 0.002; R² = 0.670; P < 0.001), subtotal BMC (ß = 0.090; R² = 0.734; P = 0.005) and lumbar-spine BMC (ß = 1.004; R² = 0.656; P = 0.010) in the adjusted analyses. However, no significant association was found between HGS and lumbar-spine BMD (ß = 0.001; R² = 0.464; P = 0.299). CONCLUSION: HGS was directly associated with BMD and BMC in HIV-infected children and adolescents.

Phase Angle Is Related to 10 m and 30 m Sprint Time and Repeated-Sprint Ability in Young Male Soccer Players.

OBJECTIVE: To examine the association between phase angle (PhA) and bioelectrical impedance vector analysis (BIVA) and components of physical performance in male youth soccer players. DESIGN: Cross-sectional. METHODS: Sixty-two players from two professional soccer academies were recruited. Electrical bioimpedance was used to obtain the PhA and BIVA. Body fat (BF) and lean soft tissue mass (LSTM) were measured by dual-energy X-ray absorptiometry. All players completed physical tests including the standing long jump (SLJ), Carminatti's test (peak speed at the end of the test, PST-CAR), 10 m and 30 m straight-line sprints, and repeated-sprint ability (RSA) test (RSAbest and RSAmean times). RESULTS: Adjusting for chronological age, BF, and LSTM, multiple regression analysis outputs showed that PhA remained inversely related to RSAmean (ß = -0.362; p < 0.001), RSAbest (ß = -0.239; p = 0.020), 10 m (ß = -0.379; p = 0.012), and 30 m (ß = -0.438; p < 0.001) sprint times, while the association with PST-CAR and SLJ performance were statistically non-significant. In addition, BIVA showed that differences in confidence ellipses were found between athletes in the reference population and the study sample (p < 0.05). The tolerance ellipses indicated that the athletes in the present study had more total body water (TCW) and lower proportions of intracellular water (ICW) to extracellular water (ECW). The reference population had more TCW and ICW/ECW. CONCLUSIONS: Our results suggest that young soccer players with higher PhA values, indicating better cell integrity and functionality, have better performance in typical anaerobic running activities, such as sprinting speed and RSA performance, adjusted to age and body composition characteristics.

Cell integrity indicators assessed by bioelectrical impedance: A systematic review of studies involving athletes.

INTRODUCTION: Bioelectrical impedance analysis (BIA) has been used to evaluate cellular health and integrity through bioelectrical indicators. In the sporting context, monitoring these indicators can be useful to assess the quality and vitality of cells and body tissues. OBJECTIVE: The aim of this systematic review was to investigate indicators of cellular health and integrity evaluated by BIA in athletes. METHODS: Searches were performed in December 2017 in the Lilacs, Medline, PubMed, Science Direct, Scielo, Scopus, SPORTDiscus, and Web of Science databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: The searches retrieved 31 articles (30 involving professional athletes and one involving university athletes). In longitudinal studies (n = 15), the bioelectrical parameters directly associated with cellular health and integrity were extracellular water (ECW), phase angle (PA), BIA vector analysis (BIVA), crude reactance data (Xc), resistance (R), and ECW/BCM ratio. Regarding the findings of cross-sectional studies (n = 16), the investigated parameters (ECW, PA, BIVA, Z, BCM, and ECW/BCM) were directly associated with gender, age, sports performance level, modality, and game position. CONCLUSIONS: In the included studies, the cellular health and integrity indicators were: Z, Xc, R, total water, intracellular water, ECW, PA, BIVA, BCM, and ECW/BCM.