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Objectives: As the first, to our knowledge, nationwide study in the Middle East and North Africa (MENA), this study aimed to investigate the association of serum 25 hydroxy vitamin D [25(OH)D] levels with cardiometabolic risk factors in a nationally representative sample of the pediatric population in Iran. The second objective was to provide the prevalence of hypovitaminosis D and the percentiles of serum 25(OH)D in the study population. Methods: This national population-based study was conducted among 1100 Iranian students living in 27 provinces in Iran. The association of 25(OH)D with each cardiometabolic risk factor was determined after adjustment for age, gender, body mass index, and waist circumference. Results: Participants consisted of 1095 students (52% boys) with a mean age of 14.74 ± 2.61 y. The median 25(OH)D level corresponded to a vitamin D insufficiency level: 12.70 ng/mL in boys and 13.20 ng/mL in girls. Overall, 40% of participants were vitamin D deficient, and 39% had vitamin D insufficiency. There were no significant differences in these findings between boys and girls. Adjusted regression analysis revealed a significant weak inverse association of 25(OH)D with systolic blood pressure, diastolic blood pressure, total cholesterol, and low-density lipoprotein cholesterol. This association was significantly positive with high-density lipoprotein cholesterol, but not with fasting plasma glucose and metabolic syndrome. Conclusion: We found a considerably high prevalence of hypovitaminosis D in the pediatric population of a sunny region. Our findings also revealed an association of hypovitaminosis D with many cardiometabolic risk factors from childhood; these associations were independent of obesity indexes. It is of special concern that the highly prevalent disorders of low 25(OH)D and low high-density lipoprotein cholesterol in children and adolescents of the MENA region had significant association. The clinical importance of our findings needs to be confirmed in longitudinal studies. [ABSTRACT FROM AUTHOR]

Background/Aims: This study aimed to test a potential model of the relationship between various cardiometabolic risk factors including obesity, unhealthy diet, low physical activity, dyslipidemia, and high blood pressure in a large population-based sample of children and adolescents. Methods: In this nationwide study, a representative sample of 5,528 students aged 10-18 years was selected by multistage random cluster sampling from 27 provinces of Iran. Demographic, anthropometric, biological, and biochemical factors were determined. Structural equation modeling (path analysis) was applied to evaluate the causal relationship between these variables. Results: The mean age of study participants was 14.7 ± 2.41 years and the mean body mass index (BMI) was 19.4 ± 4.1. Higher socioeconomic status was directly associated with unhealthy diet, low physical activity and BMI in both sexes. Age had a positive direct effect on low physical activity in both sexes. BMI showed the greatest direct effect on total cholesterol, triglyceride, low-density lipoprotein cholesterol, and mean arterial pressure in comparison with the direct effects of unhealthy diet and low physical activity. BMI was associated negatively with high-density lipoprotein cholesterol in both groups. Conclusions: No previous study has used path analysis for determining the interactions examined in this study among a nationally representative sample of children in the Middle East and North Africa (MENA). The results of this study underline the imperative need for the weight loss and lifestyle change from childhood as the first-line preventive strategy for metabolic syndrome and noncommunicable diseases. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

BACKGROUND: Obesity in accordance with metabolic syndrome (MetS) confronts populations at the higher risk of morbidity and mortality of chronic diseases including, chronic kidney diseases (CKD). The renal complication of obesity and MetS has been less debated in young adolescents. The objective of this study was to assess the kidney function in obese adolescents with or without MetS. MATERIALS AND METHODS: The data used in this study were collected as part of a national study entitled Childhood and Adolescence Surveillance and Prevention of Adult Non-communicable disease Study. The present study was conducted on a sub-sample of 113 obese adolescents (body mass index >95(th) percentile) aged between 10 years and 16 years selected by convenient sampling from the whole population studied. Anthropometric indexes and blood pressure were examined. A 12-h fasting serum was obtained for each participant to measure blood glucose, lipid profile, quantitative C-reactive protein (hs-CRP), Cystatin-c, urea, and creatinine. Fasting spot urine was collected to determine microalbumin and creatinine. Based on the study findings, participants were assigned into two groups with and without MetS. RESULTS: The mean of microalbuminuria was in similar ranges in two groups and while the mean glomerular filtration rate (GFR) calculated by Bokenkamp's, updated and combined Schwartz's formulas were significantly lower in MetS + obese group in comparison with obese group. The similar result was not achieved by Filler's formula. Among MetS components, waist circumference had a correlation with hs-CRP (P = 0.04; r = 0.15). GFR was calculated based on the Schwartz formula and Cystatin-c formulas had no significant correlation with any MetS components. CONCLUSION: Our findings suggest that MetS can increase the risk of kidney dysfunction in obese adolescents. More studies are suggested in this regard in the pediatric population. [ABSTRACT FROM AUTHOR]

Background: Little experience exists on valid and reliable tools for assessment of the determinants of underweight and overweight in children and adolescents living in the Middle-East and North Africa (MENA). This study aimed to develop a valid and wideranging questionnaire for assessment of these parameters in a nationwide sample of Iranian children and adolescents. Methods: This national study was conducted in 31 provinces in Iran. The first phase consisted of focus group discussion with 275 children and adolescents and their parents. After a qualitative content analysis, the initial items were extracted. In the next step, the face validity was assessed by expert panelists using the quantitative method of the Impact Score. To assess the content validity, the content validity rate (CVR) and the content validity index (CVI) were determined. The internal consistency was examined by Cronbach alpha, and its testretest reliability was determined. The socio-demographic variables, perinatal factors, lifestyle factors, family history, knowledge and attitude were assessed. Dietary intakes were assessed by a validated 168-item semi-quantitative food frequency questionnaire. A validated questionnaire for quality of life was filled in anonymously. Results: A team of expert researchers conducted the data analysis of 576 interviews by using qualitative content analysis method. The analysis process began by determining the semantic units about the concepts studied. The initial questionnaire was developed in four domains by including Likert scale questions. In the face validity step, all questions of the primary questionnaire obtained a score of more than 1.5. In the phase of CVR assessment, 6 questions obtained a score of less than 0.62, and were omitted. The rest of questions were assessed for CVI, and got a score of more than 0.75. Cronbach's alpha coefficient of the whole questionnaire was 0.97, and the Pearson correlation coefficient of the test-retest phase was 0.94. Conclusion: The developed questionnaire is a valid and reliable tool for assessment of the determinants of weight disorders in a nationally representative sample of children and adolescents in the MENA. [ABSTRACT FROM AUTHOR]

Background: The World Health Organization (WHO) is in the process of establishing a new global database on the growth of school children and adolescents. Limited national data exist from Asian children, notably those living in the Middle East and North Africa (MENA). This study aimed to generate the growth chart of a nationally representative sample of Iranian children aged 10-19 years, and to explore how well these anthropometric data match with international growth references.Methods: In this nationwide study, the anthropometric data were recorded from Iranian students, aged10-19 years, who were selected by multistage random cluster sampling from urban and rural areas. Prior to the analysis, outliers were excluded from the features height-for-age and body mass index (BMI)-for-age using the NCHS/WHO cut-offs. The Box-Cox power exponential (BCPE) method was used to calculate height-for-age and BMI-for-age Z-scores for our study participants. Then, children with overweight, obesity, thinness, and severe thinness were identified using the BMI-for-age z-scores. Moreover, stunted children were detected using the height-for-age z-scores. The growth curve of the Iranian children was then generated from the z-scores, smoothed by cubic S-plines. Results: The study population comprised 5430 school students consisting of 2312 (44%) participants aged 10-14 years , and 3118 (58%) with 15-19 years of age. Eight percent of the participants had low BMI (thinness: 6% and severe thinness: 2%), 20% had high BMI (overweight: 14% and obesity: 6%), and 7% were stunted. The prevalence rates of low and high BMI were greater in boys than in girls (P < 0.001). The mean BMI-for-age, and the average height-for-age of Iranian children aged 10-19 years were lower than the WHO 2007 and United states Centers for Disease Control and Prevention 2000 (USCDC2000) references. Conclusions: The current growth curves generated from a national dataset may be included for establishing WHO global database on children's growth. Similar to most low-and middle income populations, Iranian children aged 10-19 years are facing a double burden of weight disorders, notably under- and over- nutrition, which should be considered in public health policy-making. [ABSTRACT FROM AUTHOR]

Objective Depressed high-density lipoprotein cholesterol (HDL-C) is prevalent the Middle East and North Africa. Some studies have documented associations between HDL-C and several single nucleotide polymorphisms (SNPs) in candidate gene polymorphisms. Methods We investigated the associations between SNP genotypes and HDL-C levels in Iranian students, aged 10–18 years. Genotyping was performed in 750 randomly selected participants among those with low HDL-C levels (below 5th percentile), intermediate HDL-C levels (5–95th) and high HDL-C levels (above the 95th percentile). Minor allele frequencies (MAFs) of the SNPs of interest were compared between the three HDL-C groups. Results The vast majority of pairwise comparisons of MAFs between HDL-C groups were significant. Pairwise comparisons between low and high HDL-C groups showed significant between-group differences in MAFs for all SNPs, except for APOC3 rs5128. Pairwise comparisons between low and intermediate HDL-C groups showed significant between-group differences in MAFs for all SNPs, except for APOC3 rs5128 and APOA1 rs2893157. Pairwise comparisons between intermediate and high HDL-C groups showed significant between-group differences in MAFs for all SNPs, except for ABCA1 APOC3 rs5128 and APOA1 rs2893157. After adjustment for confounding factors, including age, sex, body mass index, low physical activity, consumption of saturated fats, and socioeconomic status, ABCA1 r1587K and CETP A373P significantly increased the risk of depressed HDL-C, and CETP Taq1 had a protective role. Conclusion This study replicated several associations between HDL-C levels and candidate gene SNPs from genome-wide associations with HDL-C in Iranians from the pediatric age group. [ABSTRACT FROM AUTHOR]

Background: By the current global obesogenic environment, non-alcoholic fatty liver disease is becoming an important health problem in the pediatric age group. Objectives: This study aimed to determine the first age-and gender-specific percentiles and upper limit normal limit (ULN) of alanine aminotransaminase (ALT) and aspartate aminotransaminase (AST) among a nationally-representative sample of children and adolescents in the Middle East and North Africa (MENA). The second objective was to determine the linear association of obesity indexes and age with serum ALT and AST levels. Patients and Methods: This nationwide study was conducted among a representative sample of 4078 students aged 10-18 years, who were selected by multistage random cluster sampling from 27 provinces of Iran. ALT and AST were measured on fresh sera. Body mass index (BMI) was calculated as an index of generalized obesity, and waist- to- height ratio (WHtR) as an index of abdominal obesity. The age- and gender-specific percentiles of ALT and AST were constructed, and the 95th percentile of each enzyme was considered as the ULN. Gender-specific linear regression analysis was employed to examine the association of BMI or WHtR with the levels of ALT and AST. Results: Data of ALT and AST were available for 4078 (2038 girls) and 4150 (2061 girls), respectively. Participants had a mean (SD) age of 14.71 (2.41).The ULN of ALT for boys, girls, and the total individuals were 36.00; 38.00; and, 37.00 U/L, respectively. In both genders, ALT and AST had linear association with age. The association with BMI was significant for ALT in both genders and for AST only in boys, the association of ALT with WHtR was significant in both genders; the corresponding figures were not significant for AST. Conclusions: The findings of the current study confirmed the current ULN value of 40 U/L commonly used for the pediatric age group. The linear association of indexes for generalized and abdominal obesity with ALT underscores the importance of timely prevention and control of childhood obesity. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to simplify the diagnostic criteria of pre-hypertension (pre-HTN) and hypertension (HTN) in the pediatric age group, and to determine the accuracy of these simple indexes in a nationally-representative sample of Iranian children and adolescents., Method: The diagnostic accuracy of the indexes of systolic blood pressure-to-height ratio (SBPHR) and diastolic BPHR (DBPHR) to define pre-HTN and HTN was determined by the area under the curve of the receiver operator characteristic curves., Results: The study population consisted of 5,738 Iranian students (2,875 females) with mean (SD) age of 14.7 (2.4) years. The prevalences of pre-HTN and HTN were 6.9% and 5.6%. The optimal thresholds for defining pre-HTN were 0.73 in males and 0.71 in females for SBPHR, and 0.47 in males and 0.45 in females for DBPHR, respectively. The corresponding figures for HTN were 0.73, 0.71, 0.48, and 0.46, respectively. In both genders, the accuracies of SBPHR and DBPHR in diagnosing pre-HTN and HTN were approximately 80%., Conclusions: BPHR is a valid, simple, inexpensive, and accurate tool to diagnose pre-HTN and HTN in adolescents. The optimal thresholds of SBPHR and DBPHR were consistent with the corresponding figures in other populations of children and adolescents with different racial and ethnic backgrounds. Thus, it is suggested that the use of these indexes can be generalized in programs aiming to screen elevated blood pressure in the pediatric age group., (Copyright © 2013 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.)