the global burden of disease ( gbd ) studies in 1990 , 2000 , and 2013 showed that metabolic risk factors ( mrfs ) are the most important determinants of emerging non - communicable diseases all over the world ( 1 - 8 ) . obesity has now become a common health problem and its prevalence continues to increase in both developed and developing countries ( 9 - 11 ) . the increasing incidence of childhood obesity and its attributed socioeconomic and public health burden is a real threat for developing countries ( 12 ) . recent studies reveal the increasing rates of overweight and obesity and their attributed ranges of adverse health outcomes in children and adolescents ( 13 , 14 ) . most obese children and adolescents already are at high risk for metabolic complications , and for a wide range of morbidities ( 15 , 16 ) . moreover , there are some evidence on long - term premature mortality and physical morbidity in their adulthood ( 16 , 17 ) . despite priority of the problem , there is an evident gap in the related literature on these topics ( 11 , 18 ) . even though there are a few studies on trend and point estimations of bmi trend and prevalence of obesity in iranian pediatric population , there are little information about their exposure distribution at sub - national level and no information about their trends and their effects on the health ( 7 , 12 , 19 ) . most of available reports are scattered or limited to specific sub groups of population ( 9 , 12 ) . remarkably , the reported basal information on prevalence of overweight and obesity varies considerably from one study to another . they are recruited based on different measures from different target groups of different scopes with quite different age and sex distributions ( 9 , 18 ) , so that there is a growing need to prepare primary data to bridge health research to policy recommendations ( 18 , 20 ) . to address this issue , we need to provide comprehensive scientific evidence for triggering policy actions , controlling the programs , and measuring the effect of interventions ( 21 ) . considering these , the main objective of our study was to systematically review of all available studies on the means and standard deviations of anthropometric measures including body mass index ( bmi ) ; waist circumference ( wc ) ; waist - hip ratio ( whr ) ; and waist - to - height ratio ( whtr ) , or reported prevalence of obesity or overweight by sex , age , and year at national and sub - national levels from 1990 to 2013 in iranian children and adolescents . the design and protocol of the study have been described in more detail earlier ( 22 , 23 ) . here centers for disease control and prevention , and international obesity task force each have presented different definitions of overweight and obesity in children and adolescents ( 24 - 27 ) ( table 1 ) . we have included studies that reported mean and standard deviation or percentile categories of bmi , wc , whr , or whtr or prevalence of obesity or overweight by sex , age , and year at national and sub - national levels in iran , based on anthropometric measures . for each measure , the standardized protocols , definition and cut off were considered . to assess papers on obesity and/or overweight of iranian children and adolescents , we searched pubmed and nlm gateway ( for medline ) , institute of scientific information ( isi ) , and scopus as the main international electronic data sources . moreover iranmedex , irandoc , and scientific information database ( sid ) , considered to the main domestic databases that have systematic search capability and the most coverage of national indexed or even non indexed iranian scientific journals ( table 2 ) . all iranian scientific journals of medical universities that are not listed in the domestic electronic databases , governmental reports , projects reports , conferences and reference lists , were reviewed by hand searching . we limited the search to national , provincial , district , community population based studies in iranian children and adolescents ( ages 6 - 18 years ) and there was no restriction on language . we used the aggregated data of childhood and adolescence surveillance and prevention of adult non - communicable disease ( caspian ) study as the main available national data source for the cardio metabolic risk factors of children and adolescents in iran ( 28 ) . data were collected in four different surveys during 2003 to 2012 at the national and sub - national levels in iran ( 20 , 29 - 34).we assessed first , third , and fourth rounds data since second rounds of data were not available . we excluded papers on non - population - based studies , or those with duplicate citations . the studies that focused on specific populations ( such as school - based studies ) were excluded . when there were multiple publications on the same population , only the largest study or the main source of data was included . papers that had poor ratings were excluded and data were extracted from moderate and high quality studies . the quality assessment has been followed independently by two research experts and probable discrepancy between them resolved based on third expert opinion . the data extraction sheet contained the following items : general information of study and its citation ; population detailed characteristics ; methodological information of designing and conduction of study ( the study region , scope of study ( local study or survey ) , total sample size , age and sex groups , urban / rural areas , cut - off point of prevalence , reported prevalence and its 95% confidence interval ) , and study outcomes indicators ( age specific prevalence of overweight and/or obesity ; body mass index mean ; waist circumference mean ; waist to hip ratio mean ) . the world health organization ( who ) , u.s . centers for disease control and prevention , and international obesity task force each have presented different definitions of overweight and obesity in children and adolescents ( 24 - 27 ) ( table 1 ) . we have included studies that reported mean and standard deviation or percentile categories of bmi , wc , whr , or whtr or prevalence of obesity or overweight by sex , age , and year at national and sub - national levels in iran , based on anthropometric measures . to assess papers on obesity and/or overweight of iranian children and adolescents , we searched pubmed and nlm gateway ( for medline ) , institute of scientific information ( isi ) , and scopus as the main international electronic data sources . moreover iranmedex , irandoc , and scientific information database ( sid ) , considered to the main domestic databases that have systematic search capability and the most coverage of national indexed or even non indexed iranian scientific journals ( table 2 ) . all iranian scientific journals of medical universities that are not listed in the domestic electronic databases , governmental reports , projects reports , conferences and reference lists , were reviewed by hand searching . we limited the search to national , provincial , district , community population based studies in iranian children and adolescents ( ages 6 - 18 years ) and there was no restriction on language . we used the aggregated data of childhood and adolescence surveillance and prevention of adult non - communicable disease ( caspian ) study as the main available national data source for the cardio metabolic risk factors of children and adolescents in iran ( 28 ) . data were collected in four different surveys during 2003 to 2012 at the national and sub - national levels in iran ( 20 , 29 - 34).we assessed first , third , and fourth rounds data since second rounds of data were not available . we excluded papers on non - population - based studies , or those with duplicate citations . the studies that focused on specific populations ( such as school - based studies ) were excluded . when there were multiple publications on the same population , only the largest study or the main source of data was included . papers that had poor ratings were excluded and data were extracted from moderate and high quality studies . the quality assessment has been followed independently by two research experts and probable discrepancy between them resolved based on third expert opinion . agreement was assessed using cohen s kappa statistic . the data extraction sheet contained the following items : general information of study and its citation ; population detailed characteristics ; methodological information of designing and conduction of study ( the study region , scope of study ( local study or survey ) , total sample size , age and sex groups , urban / rural areas , cut - off point of prevalence , reported prevalence and its 95% confidence interval ) , and study outcomes indicators ( age specific prevalence of overweight and/or obesity ; body mass index mean ; waist circumference mean ; waist to hip ratio mean ) . we refined data for prevalence of obesity and overweight by sex , age , province , and year ( n = 22972 ) . based on our search strategy we found 3253 records ; of these 1875 were from international data bases and the remaining 1378 were obtained from national data bases . after removing duplicates , via the refining steps , only 129 articles were found related to our study domain . figure 1 is a flowchart for the data collection and selection process . considering the inclusion and exclusion criteria , 62 articles that met our eligibility criteria were selected . from these , the extracted results of 53 papers are reported in tables 3 - 10 and the others are shown with related information in tables 11 - 13 . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . values are expressed as mean ( sd ) . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . abbreviation : ci , confidence interval ; f , female ; m , male ; na , not available ; r , rural ; r , rural total ; t , total ; u , urban ; ut , urban total ; y , year . tables 3 - 10 shows the prevalence of obesity based on bmi , in eligible population - based studies in iranian children and adolescents . also for more precise comparison , the confidence interval for 95% significance level ( ci 95% ) was calculated for possible cases . we have also included each study designed . considering the systematic review results ; the number of total population and points of data were 22972 and 29 , 38985 and 47 respectively for boys and girls . there were 5 studies that did not report bmi separately for boys and girls . as well as regarding the geographically distribution we found , 9 national , 14 provincial , and 58 district level points of data . the findings are scattered , with very wide ranges of values for bmi and for rates of obesity and overweight . on the other hand , non - standard classifications of age groups led to greater complexity in estimation of values . for instance , information about elementary school students was provided with at least 6 different age categories including : 6 - 10 , 6 - 11 , 6 - 12 , 6 - 14 , 7 - 11 , and 7 - 12 . the lowest rate of obesity in this age group was 3.5% which was reported in yazd and sabzevar ( 9 , 38 , 50 ) and the highest rate of 17.7% was in ahvaz ( 42 ) . similarly there were different reports for 10 - 15 year olds ; based on one of them 13% of boys and 6.5% of girls in tehran province were obese ( 41 ) , in another study via the refining steps , only 129 articles were found related to our study domain in the same province reported 7.5% and 7.3% respectively for boys and girls ( 55 ) . in 15 - 19 year old group , the prevalence of obesity was 2.8% for boys and 1.7% for girls ( 49 , 57 ) . in tables 11 - 13 , the whr , wc , and whtr mean in population - based studies in iranian children and adolescents reported based on papers data availability . tables 11 - 13 include only 9 papers with information on whr , wc , or whtr that met the study eligible criteria . the aggregated data caspian studies are presented as the main source of national data . based on the first caspian study in 2004 , the national prevalence of abdominal obesity was 9.27 ( 8.87% - 9.67% ) for both sexes , 9.14 ( 8.60% - 9.69% ) for males , and 9.41 ( 8.84% - 9.99% ) for females . in the last estimation for 2012 these were increased respectively to 19.12 ( 18.22% - 20.02% ) , 20.41 ( 19.09% - 23.05% ) , and 17.79 ( 16.56% - 19.02% ) . in similar time period , the national mean of wc from 64.61 ( 64.46 cm - 64.76 cm ) rose to 67.02 ( 66.57 cm - 67.48 cm ) . this review of our finding , similar to some regional and global studies , provides alarming evidence - based data on the considerable prevalence of childhood and adolescents overweight ( 9 , 12 , 16 , 17 ) . in iran national studies , especially in pediatric groups , are limited and nearly there is no comprehensive study for sub - national trends . considering the results of caspian , as the only valid national study ; in 2004 , the national prevalence of obesity for 6 - 18 year olds male and female was respectively 3.34 ( 3% - 3.69% ) and 3.50 ( 3.15% - 3.87% ) . in 2010 these estimations respectively rose to 13.58 ( 12.59% - 14.63% ) , and 7.68 ( 6.71% -8.72% ) . in the last estimation for 2012 these were increased to ; 13.58 ( 12.59% - 14.63% ) , and 10.15 ( 9.27% - 11.09% ) . different age and sex groups had large variations in the prevalence of obesity and overweight . as a considerable point ; there are also a lot of missing data for different sub groups which is leading from the misclassification or other limitation of research papers data presentation ( 89 , 90 ) . some of these diversities are attributed to the geographical scopes of studies ; some estimations belong to local level studies , some others estimate district level and others are designed for national estimations . moreover , the quality of presented data , and some methodological problems , in designing and conducting the related researches , were other sources of diversity ( 30 , 32 , 85 ) . there are also some visible data lags in some areas of country or for different target groups that should be more considered for future studies plan . for all measures however the reports have significant missing in reporting the confidence intervals for both measures values and obesity / overweight rates , which limited our ability to compare and analyze results . on the other hand , most of our efforts to contact study authors for requesting more data and information failed . in iran there are few national studies and nearly no comprehensive study for sub - national trends ( 91 - 93 ) . in comparison with other related studies , compared with the gbd studies with overall 102 points of data , we benefit from more data driven estimations rather than the model driven results . we will provide more data points that lead to higher quality of estimation ( 1 , 4 - 8 , 19 ) . this is the first comprehensive systematic approach to search and data gathering , during which we benefited from the highest level of access to the published , available unpublished and grey literature through the comprehensive hand searching process . we had access to main national sources of caspian study ( 30 , 32 , 85 ) . this study presents the most scientific evidences for the prevalence and trends of obesity and overweight in pediatric population from 1990 to 2013 . all of domestic data bases were searched exactly with all of english / persian equivalent search terms .   because of scarcity of data , variations in groups studied , differences in living areas ( urban / rural ) , discrepancy of the measures , for comparing and aggregating the information , we need more modern practical statistical methods ( 9 , 12 ) . these methods are advanced regression models , using existing data , benefit from models for age , hierarchical pattern of data , spatial and temporal pattern of data , and covariates ( 94 , 95 ) . the present study summarized the information of studies on mean and standard deviation of different measures including bmi , wc , whr , or whtr and reported prevalence of obesity or overweight by sex , age , and year at national and sub - national levels from 1990 to 2013 in iranian children and adolescents . several methods have been proposed in the field of medical and surgical treatments . in this context , recent promising approaches emphasize on the population based interventions impacts ( 96 ) . aiming that , we call for a sustained valid data sources to monitor , prevent , and control of pediatric overweight and obesity . these processes should be followed through ongoing community - based lifestyle intervention on diet , physical activity promotion , and other local and national experiences ( 31 , 56 , 87 , 97 ) . evidences reveal that for more effectiveness , these interventions should be started and exactly followed from the adolescence ( 12 , 23 , 96 ) . health researchers , professionals and policy - makers should focus on more evidence based policies which require more reliable data . aiming that , all processes of designing ; conducting ; monitoring ; and distribution of data should be managed based on advanced scientific methods ( 18 , 98 ) . in conclusion , the present findings could provide practical information on children and adolescents overweight and obesity for better health policy and more detailed design studies in this area . because of the importance of application of researches data more policy attention should be considered for more efficient papers data presentation . the presented results also could be used for future complementary sub - national , national or even global related studies .
contextobesity has now become a common health problem worldwide . to gain insight into the epidemiology of the problem in iran 
 , we systematically reviewed all available studies on the prevalence of overweight and obesity in the iranian pediatric population.evidence acquisitionwe systematically searched pubmed , isi , scopus , as well as iranmedex , irandoc , and scientific information database ( sid ) databases.all studies on mean and standard deviation or percentile categories of bmi , wc , whr , or whtr or prevalence of obesity / overweight in iranian child and adolescence , were performed from january 1990 to the end of december 2013 . 
 refining processes were conducted by two independent reviewers . quality assessment and 
 data extraction followed based on validated form . 
 as , these data were heterogeneous , meta - analysis was not performed.resultsfrom 3253 records , through three refining steps , 129 articles were found related to our study . in iran , 
 national studies are limited and nearly there is no comprehensive study for sub - national trends . 
 different age and sex groups had large variations in the prevalence of obesity and overweight ( from 1% up to 16.1% and from 4.4% up to 42.3% respectively for obesity and overweight ) . 
 conclusionsrelated data are very scattered or limited to some specific subgroups in some living areas . for comparing , aggregating , and imputing the information we need more modern practical statistical methods .