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Studies have reported conflicting results on the association between handgrip strength (HGS) and blood pressure during childhood and adolescence. High multicollinearity involving somatic components that influence both HGS and blood pressure might be an important source of bias. This study sought to investigate the independent effects of HGS and muscle mass on blood pressure levels in children and adolescents. Muscle mass and fat mass (Multifrequency Electrical Bioimpedance) and systolic (SBP) and diastolic (DBP) blood pressure (Automatic oscillometric device) were assessed in 833 volunteers aged 6-18 years, of both sexes. Handgrip strength-for-age quartiles were calculated and participants were assigned to groups by HGS quartiles. Analysis of covariance was conducted to address the linear association between HGS and SBP adjusted for height, muscle mass, and fat mass. To test for linear trend, contrast analysis was conducted. Partial eta-squared was used to confirm or rule out a small significant effect of the independent variables on SBP. The effect size of HGS on SBP was not significant in both sexes. In girls, 1.7% of the between-groups variance in SBP was accounted for by muscle mass (P = 0.016). In boys, 2.3% and 1.8% of the between-groups variance in SBP was accounted for by muscle mass (P = 0.001) and height (P = 0.005), respectively. In conclusion, children with a more advanced physical maturity for their age, that is, who are taller, stronger, and have greater fat-free mass, may be nearly reaching the physiological parameters of adulthood, and consequently have higher systolic blood pressure., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

This study aimed to evaluate the enzymatic activity of the angiotensin-converting enzyme (ACE) in children and adolescents to investigate their relationship with dyslipidemia and other cardiometabolic alterations. Anthropometric measurements, blood pressure (BP), and fasting lipid concentrations were taken from 360 subjects. Categorization was done according to the levels of each lipoprotein (total cholesterol, triglycerides (TG), LDL-C, HDL-C, and non-HDL-C) into three groups: normolipidemic (NL), borderline (BL), and dyslipidemic (DL). Enzymatic activity in urine was measured using the substrates Z-FHL-OH and hippuryl-HL-OH (h-HL-OH) and the ACE activity ratio (Z-FHL-OH/h-HL-OH) was calculated. Dyslipidemic levels of HDL-C, TG, and LDL-C were observed in 23%, 9%, and 3% of the participants, respectively, and were more frequent in obese children (Chi-square, p < 0.001). ACE activity ratio was augmented in BL(HDL-C) when compared to NL(HDL-C) (5.06 vs. 2.39, p < 0.01), in DL(LDL-C) in comparison to BL(LDL-C) and NL(LDL-C) (8.7 vs. 1.8 vs. 3.0, p < 0.01), and in DL(non-HDL-C) than in BL(non-HDL-C) and in NL(non-HDL-C) (6.3 vs. 2.1 vs. 2.9, p = 0.02). The groups with impaired HDL-C and TG levels presented an increased diastolic BP percentile, and a higher systolic BP percentile was observed in BL(TG) and DL(TG). The carotidal-femoral pulse wave velocity (cfPWV) was higher in the groups with DL levels of TG and LDL-C than in NL groups. Hypertriglyceridemia was associated with higher cfPWV. No direct impact of the ACE activity on BP values was observed in this cohort, however, there was an association between hyperlipidemia and ACE upregulation which can trigger mechanisms driving to early onset of hypertension and cardiovascular disease. Graphical abstract exemplifying the cohort, categorization of subjects into the groups NL normolipidemic, BL borderline, DL dyslipidemic, methods, and main findings. Pediatric dyslipidemia was consistent with dyslipidemia secondary to obesity (DSO), associated with higher urinary angiotensin-converting enzyme (ACE) activity ratio, BP blood pressure values, and carotidal-femoral pulse wave velocity (cfPWV)., (© 2023. The Author(s), under exclusive licence to The Japanese Society of Hypertension.)

Objective: This study aimed to verify vitamin D concentration in children and adolescents during the seasons of the year and to compare vitamin D concentration between children engaged in outdoor activities and those engaged in indoor activities., Methods: This is a cross-sectional study with a sample of 708 children and adolescents (aged 6-18 years), excluding 109 (16 were over 19 years old; 39 had a disease that required continuous treatment; 20 were on continuous medication; and 34 had no vitamin D data), ending with 599. The plasma concentration of 25-hydroxyvitamin D2 was measured with commercial kits following manufacturer instructions., Results: Participants who engaged in outdoor activities, as well as those who had data collected during summer and spring, had higher levels of vitamin D. According to the Poisson regression, the proportion of participants with inadequate levels of vitamin D was greater in the participants whose vitamin D was measured during spring (PR 1.15, 95%CI 1.03-1.29) and winter (PR 1.18, 95%CI 1.05-1.32). Also, a greater proportion of inadequate vitamin D was observed for those engaged in indoor activities (PR 1.08, 95%CI 1.01-1.15)., Conclusions: Participants who measured the vitamin during the summer and autumn had a lower prevalence of hypovitaminosis D. Even in regions with high solar incidence throughout the year, vitamin D levels can vary significantly during the period's seasons.

Background: Sedentary behavior has been associated with several cardiometabolic risk factors during childhood. However, little is known about the impact of sedentary behavior on the health and eating habits of physically active children and adolescents., Objective: To evaluate the association between sedentary behavior and cardiometabolic risk factors and eating habits in physically active children and adolescents., Methods: This cross-sectional study was conducted, including 516 physically active children and adolescents (10 to 18 years old; both sexes) enrolled in the social project "Estação Conhecimento-Vale" were evaluated. Biochemical and lifestyle variables (questionnaire) were collected. Sedentary behavior was determined indirectly (questionnaire), by using sitting time ≥ 3 hours per day as a cutoff point. A p-value < 0.05 was considered statistically significant for all tests., Results: Sedentary behavior was not associated with overweight/obesity (odds ratio = 0.72 [95% confidence interval (CI): 0.325-1.389]), hypertriglyceridemia (odds ratio = 0.63 [95% CI: 0.306-1.297]), low HDL cholesterol (odds ratio = 0.57 [95% CI: 0.323-1.019]), or high non-HDL cholesterol (odds ratio = 0.63 [95% CI: 0.283-1.389]). However, children and adolescents with sedentary behavior were more likely to regularly consume food in front of the television (odds ratio = 1.96 [95% CI: 1.114-3.456]) and to consume at least one ultra-processed food per day (odds ratio = 2.42 [95% CI: 1.381-4.241]). In addition, they were less likely to consume fruit regularly (odds ratio = 0.52 [95% CI: 0.278-0.967])., Conclusion: There was no association between sedentary behavior and cardiometabolic risk factors in physically active children and adolescents. However, sedentary behavior was associated with inadequate eating habits. Thus, we may suggest that the regular engagement in physical activity may attenuate the deleterious effects of sedentary behavior on the cardiometabolic parameters of children and adolescents.

Background: Our purpose was to determine reference values and determinants of serum uric acid (SUA) in children and adolescents., Methods: A fasting blood sample was collected from 1750 schoolchildren and adolescents (6-17 years). Puberty was defined according to the Tanner scale. Bodyweight, muscle mass, and body fat percentage were determined by bioimpedance. Data are given as cut-offs and mean ± standard deviation., Results: SUA level was higher in children that had already entered puberty (4.2 ± 1.1 mg/dL) than among prepubescent (3.6 ± 0.8 mg/dL; p < 0.01). Considering the 90 percentile (p90) as the upper reference value, the following values are proposed for boys and girls, respectively: <10 years or prepubescent: ≤4.5 mg/dL and ≤4.8 mg/dL; from 10 to 13 years: ≤5.7 mg/dL and ≤5.2 mg/dL; from 14 to 17 years: ≤6.4 mg/dL and ≤5.3 mg/dL. Muscle mass explained part of the variability in SUA after pubescence, acting as an independent variable for higher levels of SUA., Conclusions: The sex, age, and phase of puberty influence SUA reference levels, and part of this influence could be explained by the higher muscle mass, mainly after the adolescence onset., Impact: The key message of this study is that high levels of uric acid in the blood are associated with metabolic syndrome and cardiovascular risk factors. These diseases should be prevented since the infancy However, it is necessary to establish reference values of uric acid (SUA) for children and adolescents. The Brazilian population is highly admixed and these values were not determined so far. We studied a robust sample of Brazilian schoolchildren and adolescents (6-17 years) and defined the 90th percentile of uric acid as the upper limit of normality for sex, age, and pubertal stage. These values can be used as a reference for other populations with similar characteristics.

Background and Aim: Hyperuricemia in adults is associated with cardiovascular risk factors. However, there is less data regarding this association in children and adolescents. Our purpose was to determine association between serum uric acid (SUA) and cardiovascular risk., Methods and Results: A fasting blood sample was collected from 1750 participants aged 6-17 years enrolled in a social project and public schools in Espírito Santo, Brazil. Internal cut-offs were generated to define high SUA (≥90th percentile of SUA concentration for sex and age group). Body mass index percentile (pBMI), body fat percentage (BFP) and muscle mass were determined by bioimpedance. Data are given as mean ± standard deviation. High SUA was associated with overweight/obesity (OR 3.7 CI 95% 2.7-5.0), high waist circumference (WC) (OR 3.9 CI 95% 2.9-5.4), low HDL (OR 2.0 CI 95% 1.5-2.8), high blood pressure (BP) (OR 1.8 CI 95% 1.1-3.2), high BFP (OR 4.1 CI 95% 2.7-6.4), metabolic syndrome (MetS) (OR 3.6 CI 95% 1.8-7.1) and insulin resistance (OR 1.7 CI 95% 1.1-2.7). Individuals in the fourth quartile of SUA, compared to those in the first quartile, showed higher age, pBMI, WC, BFP and muscle mass. Using a reference value of 5.5 mg/dL, the prevalence of hyperuricemia in the sample was 10.3% (CI 95% 8.9-11.7%)., Conclusion: Higher SUA values are associated with higher cardiovascular risk in childhood and adolescence. The main cardiovascular risk factors associated with hyperuricemia were overweight/obesity, high WC, dyslipidemia, high BFP, high BP, insulin resistance and MetS., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose., (Copyright © 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Background and Aim: Uric acid (UA) is an end-product of purine catabolism and its increase in blood is a risk factor for several diseases. UA levels in men are usually higher than in women. This difference is partially due to sex hormones. We sought to investigate the onset of sexual difference in UA levels during pubertal development and the determinants of UA levels in children and adolescents., Methods and Results: The muscle mass and fat mass were measured by multi-frequency bioelectrical impedance in a cross-sectional study involving 823 children and adolescents (both sexes; 6-18 years). Serum UA was determined using a commercially available kit. UA levels started to become higher in boys (5.0 ± 1.0 mg/dL) than in girls (4.1 ± 0.9 mg/dL) around 13 years. Boys in the highest quartile of muscle mass presented higher UA levels (5.2 ± 0.7 mg/dL) when compared with the third (4.2 ± 0.7 mg/dL), second (3.7 ± 0.9 mg/dL) and first (3.4 ± 0.9 mg/dL). Similarly, girls in the highest quartile of muscle mass presented higher UA levels (4.2 ± 0.7 mg/dL) when compared with the second (3.8 ± 0.9 mg/dL) and first (3.3 ± 0.9 mg/dL). Muscle mass explained 43.0% and 7.7% of the variability of UA in boys and girls, respectively., Conclusion: Sexual differences in serum UA levels begin at puberty and partially result from a direct influence of muscle mass., (Copyright © 2019 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

We studied the relationship between different anthropometric indexes and plasma lipids. Data were collected from 2014 to 2016 in 854 schoolchildren (6-18 years). Waist circumference (WC), body fat percentage (BFP) by bioimpedance, body mass index (BMI), and waist-to-height ratio (WHtR) were measured. Total cholesterol (TC), HDLc, and triglycerides were measured in fasting blood samples and Non-HDL cholesterol (Non-HDLc) was calculated. Data are presented as mean ± standard deviation, with percentages. Means were compared using the t test or ANOVA followed by Tukey's test. The association between variables was tested by linear regression. The study was approved by the Research Ethics Committee of the Universidade Federal do Espírito Santo. Obese boys had higher TC, non-HDLc, and LDLc than eutrophic boys (p < 0.05). In girls this difference was found only for non-HDLc (p < 0.05). Children with inappropriate BFP and WHtR presented higher LDLc and non-HDLc concentrations (p < 0.001), which showed positive association (p<0.001) with lipid fractions (TC and non-HDLc). Excess body fat increased the probability of cholesterol above the reference value (170 mg/dL) by 21%. Excess body fat was associated with an atherogenic lipid profile (higher non-HDLc), especially in boys.

Pediatric elevated blood pressure (BP) and hypertension are usually defined using traditional BP tables at the 90th and 95th percentiles, respectively, based on sex, age, and height, which are cumbersome to use in clinical practice. The authors aimed to assess the performance of the static cut-points (120/80 mm Hg and 130/80 mm Hg for defining elevated BP and hypertension for adolescents, respectively; and 110/70 mm Hg and 120/80 mm Hg for children, respectively) in predicting increased arterial stiffness. Using data from five population-based cross-sectional studies conducted in Brazil, China, Korea, and New Zealand, a total of 2546 children and adolescents aged 6-17 years were included. Increased arterial stiffness was defined as pulse wave velocity ≥sex-specific, age-specific, and study population-specific 90th percentile. Compared to youth with normal BP, those with hypertension defined using the 2017 American Academy of Pediatrics guideline (hereafter referred to as "percentile-based cut-points") and the static cut-points were at similar risk of increased arterial stiffness, with odds ratios and 95% confidence intervals of 2.35 (1.74-3.17) and 3.07 (2.20-4.28), respectively. Area under the receiver operating characteristic curve and net reclassification improvement methods confirmed the similar performance of static cut-points and percentile-based cut-points (P for difference > .05). In conclusion, the static cut-points performed similarly well when compared with the percentile-based cut-points in predicting childhood increased arterial stiffness. Use of static cut-points to define hypertension in childhood might simplify identification of children with abnormal BP in clinical practice., (©2019 Wiley Periodicals, Inc.)

Background: We aimed to compare the accuracy of the ponderal index (PI) vs. BMI-for-age z-scores transformed (BMIz) in estimating body fat levels and classifying obesity in children and adolescents from a Brazilian urban population., Methods: This is a cross-sectional study with 1149 participants (53.2% male), aged 6 to 18 years. Body fat percent (BFP) was obtained by multi-frequency bioelectrical impedance. Non-linear regression analysis provided the accuracy of both BMIz and PI in estimating BFP. False positive rate was obtained from the proportion of individuals placed at or above the 95 th percentile for BMIz or PI, whereas their BFP was discordantly below the 95 th percentile., Results: PI and BMIz appeared with similar stability from childhood to adolescence for both boys and girls. The portion of the variability in BFP explained by BMIz (R 2  = 0.74 and R 2  = 0.75) was close to the variability in BFP explained by PI (R 2  = 0.73 and R 2  = 0.75) for boys and girls, respectively. False positive rate was higher for BMIz compared with PI among boys (21.8% vs. 3.9%) and girls (28.5% vs. 17.5%)., Conclusions: PI is a promising index for replacing BMIz in children and adolescents due to its potential to reduce false diagnosis of obesity.

Objective: To assess whether the indicators of weight status body mass index and waist-to-height ratio are similar to body fat percentage to identify obese children and adolescents with unfavorable lipid profile., Methods: This was a cross-sectional study involving 840 children and adolescents (6-18 years). The same individuals were classified as non-obese (

95 ) or obese (≥P 95 ) according to body fat percentage and indicators of weight status, body mass index, and waist-to-height ratio. Body fat percentage was obtained by multi-frequency bioelectrical impedance. Linear association between obesity and increased lipid fractions was tested by ANCOVA. Normal distribution curves of non-HDL cholesterol were designed for obese and non-obese. To provide the proportion of obese individuals with elevated non-HDL-c across all indicators, Z-score was calculated., Results: Obese boys presented higher non-HDL cholesterol when compared with those non-obese, classified by body mass index (107±28 vs. 94±25mg/dL, p=0.001), waist-to-height ratio (115±29 vs. 94±25mg/dL, p<0.001) and body fat percentage (119±33 vs. 94±24mg/dL, p<0.001). Differently, obese girls presented with higher non-HDL cholesterol when compared with those non-obese only according to the body fat percentage classification (118±24 vs. 96±26mg/dL, p=0.001). A large shift to the right in the distribution curve of non-HDL cholesterol among obese girls compared with non-obese was observed only when body fat percentage was used to discriminate between obese and non-obese., Conclusion: Body fat percentage was better than the indicators of weight status to identify children and adolescents with unfavorable lipid profile, mainly among girls., (Copyright © 2018 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.)

Objective: Angola is a sub-Saharan African country where the population has scarce access to lipidlowering medication. We sought to determine the frequency of lipid disorders among Angolan nonusers of lipid-lowering medication., Material and Methods: A cross-sectional descriptive study was carried out in a sample of 604 workers from the public sector. Blood pressure and anthropometric data were measured along with biochemical parameters including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). LDL-C to HDL-C ratio (LDL-C/HDL-C) was obtained from LDL-C and HDL-C levels., Results: High frequencies of elevated blood pressure (44.8%), metabolic syndrome (20.2%), increased TC (39.2%) and increased LDL-C (19.3%) were found. Low HDL-C was more frequent in women (62.4% vs. 36.1%, p < 0.001). Isolated hypercholesterolemia was more frequent in men (9.6% vs. 2.5%, p < 0.001). Among men TC, TG, LDL-C and LDL-C/HDL-C ratio were higher and HDL-C was lower in obese than in low-weight and normal-weight participants. Among women TC, TG, LDL-C and LDL-C/HDL-C ratio were higher in obese than in normal-weight participants. Significant linear trend of increasing TC and LDL-C levels as age increased was detected for both genders (p for trend < 0.05)., Conclusion: The results of our study showed a high frequency of lipid disorders in Angolan non-users of lipid-lowering medication.

Background: Increased stiffness of large arteries is an important determinant of cardiovascular disease risk. Higher values of arterial stiffness measured by carotid-femoral pulse wave velocity (cf-PWV) have been measured in adult African-Americans compared with whites. Studies assessing ethnic differences in cf-PWV among children and adolescents are scarce. This study sought to evaluate the association between ethnicity and cf-PWV in Brazilian children and adolescents., Methods: Seven hundred and seventy-one children and adolescents (211 blacks and 560 nonblacks, 11.3 ± 2.7 years) were included. Arterial stiffness was evaluated by cf-PWV. The ethnic classification was obtained by a single interviewer according to general phenotypes such as skin color, hair shape and facial traces., Results: Blood pressure was similar in blacks and nonblacks across all pubertal stages. Differently, cf-PWV was higher in blacks than nonblacks pubescent (5.9 ± 0.7 vs. 5.6 ± 0.8 m/s, P = 0.001) and postpubescent (6.1 ± 0.7 vs. 5.7 ± 0.7 m/s, P = 0.042), whereas no difference was detected between blacks and nonblacks prepubescent. These analyses were adjusted for sex, age, height, BMI, SBP and heart rate., Conclusion: Our study showed that higher cf-PWV values in blacks appear in adolescence and are independent of blood pressure values. Therefore, our data suggest adolescence as the key phase for the appearance of the vascular profile found in adults black individuals.