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1.  Neighborhood Disparities in Prevalence of Childhood Obesity Among Low-Income Children Before and After Implementation of New York City Child Care Regulations 
Introduction
New York City Article 47 regulations, implemented in 2007, require licensed child care centers to improve the nutrition, physical activity, and television-viewing behaviors of enrolled children. To supplement an evaluation of the Article 47 regulations, we conducted an exploratory ecologic study to examine changes in childhood obesity prevalence among low-income preschool children enrolled in the Nutrition Program for Women, Infants, and Children (WIC) in New York City neighborhoods with or without a district public health office. We conducted the study 3 years before (from 2004 through 2006) and after (from 2008 through 2010) the implementation of the regulations in 2007.
Methods
We used an ecologic, time-trend analysis to compare 3-year cumulative obesity prevalence among WIC-enrolled preschool children during 2004 to 2006 and 2008 to 2010. Outcome data were obtained from the New York State component of the Centers for Disease Control and Prevention’s Pediatric Nutrition Surveillance System.
Results
Early childhood obesity prevalence declined in all study neighborhoods from 2004–2006 to 2008–2010. The greatest decline occurred in Manhattan high-risk neighborhoods where obesity prevalence decreased from 18.6% in 2004–2006 to 15.3% in 2008–2010. The results showed a narrowing of the gap in obesity prevalence between high-risk and low-risk neighborhoods in Manhattan and the Bronx, but not in Brooklyn.
Conclusion
The reductions in early childhood obesity prevalence in some high-risk and low-risk neighborhoods in New York City suggest that progress was made in reducing health disparities during the years just before and after implementation of the 2007 regulations. Future research should consider the built environment and markers of differential exposure to known interventions and policies related to childhood obesity prevention.
doi:10.5888/pcd11.140152
PMCID: PMC4208999  PMID: 25321632
2.  Genetic Markers of Adult Obesity Risk Are Associated with Greater Early Infancy Weight Gain and Growth 
PLoS Medicine  2010;7(5):e1000284.
Ken Ong and colleagues genotyped children from the ALSPAC birth cohort and showed an association between greater early infancy gains in weight and length and genetic markers for adult obesity risk.
Background
Genome-wide studies have identified several common genetic variants that are robustly associated with adult obesity risk. Exploration of these genotype associations in children may provide insights into the timing of weight changes leading to adult obesity.
Methods and Findings
Children from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort were genotyped for ten genetic variants previously associated with adult BMI. Eight variants that showed individual associations with childhood BMI (in/near: FTO, MC4R, TMEM18, GNPDA2, KCTD15, NEGR1, BDNF, and ETV5) were used to derive an “obesity-risk-allele score” comprising the total number of risk alleles (range: 2–15 alleles) in each child with complete genotype data (n = 7,146). Repeated measurements of weight, length/height, and body mass index from birth to age 11 years were expressed as standard deviation scores (SDS). Early infancy was defined as birth to age 6 weeks, and early infancy failure to thrive was defined as weight gain between below the 5th centile, adjusted for birth weight. The obesity-risk-allele score showed little association with birth weight (regression coefficient: 0.01 SDS per allele; 95% CI 0.00–0.02), but had an apparently much larger positive effect on early infancy weight gain (0.119 SDS/allele/year; 0.023–0.216) than on subsequent childhood weight gain (0.004 SDS/allele/year; 0.004–0.005). The obesity-risk-allele score was also positively associated with early infancy length gain (0.158 SDS/allele/year; 0.032–0.284) and with reduced risk of early infancy failure to thrive (odds ratio  = 0.92 per allele; 0.86–0.98; p = 0.009).
Conclusions
The use of robust genetic markers identified greater early infancy gains in weight and length as being on the pathway to adult obesity risk in a contemporary birth cohort.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
The proportion of overweight and obese children is increasing across the globe. In the US, the Surgeon General estimates that, compared with 1980, twice as many children and three times the number of adolescents are now overweight. Worldwide, 22 million children under five years old are considered by the World Health Organization to be overweight.
Being overweight or obese in childhood is associated with poor physical and mental health. In addition, childhood obesity is considered a major risk factor for adult obesity, which is itself a major risk factor for cancer, heart disease, diabetes, osteoarthritis, and other chronic conditions.
The most commonly used measure of whether an adult is a healthy weight is body mass index (BMI), defined as weight in kilograms/(height in metres)2. However, adult categories of obese (>30) and overweight (>25) BMI are not directly applicable to children, whose BMI naturally varies as they grow. BMI can be used to screen children for being overweight and or obese but a diagnosis requires further information.
Why Was This Study Done?
As the numbers of obese and overweight children increase, a corresponding rise in future numbers of overweight and obese adults is also expected. This in turn is expected to lead to an increasing incidence of poor health. As a result, there is great interest among health professionals in possible pathways between childhood and adult obesity. It has been proposed that certain periods in childhood may be critical for the development of obesity.
In the last few years, ten genetic variants have been found to be more common in overweight or obese adults. Eight of these have also been linked to childhood BMI and/or obesity. The authors wanted to identify the timing of childhood weight changes that may be associated with adult obesity. Knowledge of obesity risk genetic variants gave them an opportunity to do so now, without following a set of children to adulthood.
What Did the Researchers Do and Find?
The authors analysed data gathered from a subset of 7,146 singleton white European children enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) study, which is investigating associations between genetics, lifestyle, and health outcomes for a group of children in Bristol whose due date of birth fell between April 1991 and December 1992. They used knowledge of the children's genetic makeup to find associations between an obesity risk allele score—a measure of how many of the obesity risk genetic variants a child possessed—and the children's weight, height, BMI, levels of body fat (at nine years old), and rate of weight gain, up to age 11 years.
They found that, at birth, children with a higher obesity risk allele score were not any heavier, but in the immediate postnatal period they were less likely to be in the bottom 5% of the population for weight gain (adjusted for birthweight), often termed “failure to thrive.” At six weeks of age, children with a higher obesity risk allele score tended to be longer and heavier, even allowing for weight at birth.
After six weeks of age, the obesity risk allele score was not associated with any further increase in length/height, but it was associated with a more rapid weight gain between birth and age 11 years. BMI is derived from height and weight measurements, and the association between the obesity risk allele score and BMI was weak between birth and age three-and-a-half years, but after that age the association with BMI increased rapidly. By age nine, children with a higher obesity risk allele score tended to be heavier and taller, with more fat on their bodies.
What Do These Findings Mean?
The combined obesity allele risk score is associated with higher rates of weight gain and adult obesity, and so the authors conclude that weight gain and growth even in the first few weeks after birth may be the beginning of a pathway of greater adult obesity risk.
A study that tracks a population over time can find associations but it cannot show cause and effect. In addition, only a relatively small proportion (1.7%) of the variation in BMI at nine years of age is explained by the obesity risk allele score.
The authors' method of finding associations between childhood events and adult outcomes via genetic markers of risk of disease as an adult has a significant advantage: the authors did not have to follow the children themselves to adulthood, so their findings are more likely to be relevant to current populations. Despite this, this research does not yield advice for parents how to reduce their children's obesity risk. It does suggest that “failure to thrive” in the first six weeks of life is not simply due to a lack of provision of food by the baby's caregiver but that genetic factors also contribute to early weight gain and growth.
The study looked at the combined obesity risk allele score and the authors did not attempt to identify which individual alleles have greater or weaker associations with weight gain and overweight or obesity. This would require further research based on far larger numbers of babies and children. The findings may also not be relevant to children in other types of setting because of the effects of different nutrition and lifestyles.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000284.
Further information is available on the ALSPAC study
The UK National Health Service and other partners provide guidance on establishing a healthy lifestyle for children and families in their Change4Life programme
The International Obesity Taskforce is a global network of expertise and the advocacy arm of the International Association for the Study of Obesity. It works with the World Health Organization, other NGOs, and stakeholders and provides information on overweight and obesity
The Centers for Disease Control and Prevention (CDC) in the US provide guidance and tips on maintaining a healthy weight, including BMI calculators in both metric and Imperial measurements for both adults and children. They also provide BMI growth charts for boys and girls showing how healthy ranges vary for each sex at with age
The Royal College of Paediatrics and Child Health provides growth charts for weight and length/height from birth to age 4 years that are based on WHO 2006 growth standards and have been adapted for use in the UK
The CDC Web site provides information on overweight and obesity in adults and children, including definitions, causes, and data
The CDC also provide information on the role of genes in causing obesity.
The World Health Organization publishes a fact sheet on obesity, overweight and weight management, including links to childhood overweight and obesity
Wikipedia includes an article on childhood obesity (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
doi:10.1371/journal.pmed.1000284
PMCID: PMC2876048  PMID: 20520848
3.  Augmenting BMI and Waist-Height Ratio for Establishing More Efficient Obesity Percentiles among School-going Children 
Research Questions
1. Are all the existing methods for estimating the obesity and overweight in school going children in India equally efficient? 2. How to derive more efficient obesity percentiles to determine obesity and overweight status in school-going children aged 7–12 years old?
Objectives
1. To investigate and analyze the prevalence rate of obesity and overweight children in India, using the established standards. 2. To compare the efficiency among the tools with the expected levels in the Indian population. 3. To establish and demonstrate the higher efficiency of the proposed percentile chart.
Study Design
A cross-sectional study using a completely randomized design.
Settings
Government, private-aided, unaided, and central schools in the Thrissur district of Kerala.
Participants
A total of 1500 boys and 1500 girls aged 7–12 years old.
Results
BMI percentiles, waist circumference percentiles, and waist to height ratio are the ruling methodologies in establishing the obese and overweight relations in school-going children. Each one suffers from the disadvantage of not considering either one or more of the obesity contributing factors in human growth dynamics, the major being waist circumference and weight. A new methodology for mitigating this defect through considering BMI and waist circumference simultaneously for establishing still efficient percentiles to arrive at obesity and overweight status is detailed here. Age-wise centiles for obesity and overweight status separately for boys and girls aged 7–12 years old were established. Comparative efficiency of this methodology over BMI had shown that this could mitigate the inability of BMI to consider waist circumference. Also, this had the advantage of considering body weight in obesity analysis, which is the major handicap in waist to height ratio. An analysis using a population of 1500 boys and 1500 girls has yielded 3.6% obese and 6.2% overweight samples, which is well within the accepted range for Indian school-going children.
Conclusion
The percentiles for school-going children based on age and sex were derived by comparing all other accepted standards used for measurement of obesity and overweight status. Hence, augmenting BMI and waist to height ratio is considered to be the most reliable method for establishing obesity percentiles among school-going children.
doi:10.4103/0970-0218.51233
PMCID: PMC2731976  PMID: 19714259
BMI; children; India; methodology; nutrition; overweight; percentile chart; waist circumference; waist-height ratio
4.  Augmenting BMI and Waist-Height Ratio for Establishing More Efficient Obesity Percentiles among School-going Children 
Research Questions:
1. Are all the existing methods for estimating the obesity and overweight in school going children in India equally efficient? 2. How to derive more efficient obesity percentiles to determine obesity and overweight status in school-going children aged 7-12 years old?
Objectives:
1. To investigate and analyze the prevalence rate of obesity and overweight children in India, using the established standards. 2. To compare the efficiency among the tools with the expected levels in the Indian population. 3. To establish and demonstrate the higher efficiency of the proposed percentile chart.
Study Design:
A cross-sectional study using a completely randomized design.
Settings:
Government, private-aided, unaided, and central schools in the Thrissur district of Kerala.
Participants:
A total of 1500 boys and 1500 girls aged 7-12 years old.
Results:
BMI percentiles, waist circumference percentiles, and waist to height ratio are the ruling methodologies in establishing the obese and overweight relations in school-going children. Each one suffers from the disadvantage of not considering either one or more of the obesity contributing factors in human growth dynamics, the major being waist circumference and weight. A new methodology for mitigating this defect through considering BMI and waist circumference simultaneously for establishing still efficient percentiles to arrive at obesity and overweight status is detailed here. Age-wise centiles for obesity and overweight status separately for boys and girls aged 7-12 years old were established. Comparative efficiency of this methodology over BMI had shown that this could mitigate the inability of BMI to consider waist circumference. Also, this had the advantage of considering body weight in obesity analysis, which is the major handicap in waist to height ratio. An analysis using a population of 1500 boys and 1500 girls has yielded 3.6% obese and 6.2% overweight samples, which is well within the accepted range for Indian school-going children.
Conclusion:
The percentiles for school-going children based on age and sex were derived by comparing all other accepted standards used for measurement of obesity and overweight status. Hence, augmenting BMI and waist to height ratio is considered to be the most reliable method for establishing obesity percentiles among school-going children.
doi:10.4103/0970-0218.51233
PMCID: PMC2731976  PMID: 19714259
BMI; children; India; methodology; nutrition; overweight; percentile chart; waist circumference; waist-height ratio
5.  Prevalence and socioeconomic correlates of overweight and obesity among Pakistani primary school children 
BMC Public Health  2011;11:724.
Background
Childhood obesity is becoming an equally challenging, yet under-recognized, problem in developing countries including Pakistan. Children and adolescents are worst affected with an estimated 10% of the world's school-going children being overweight and one quarter of these being obese. The study aimed to assess prevalence and socioeconomic correlates of overweight and obesity, and trend in prevalence statistics, among Pakistani primary school children.
Methods
A population-based cross-sectional study was conducted with a representative multistage cluster sample of 1860 children aged 5-12 years in Lahore, Pakistan. Overweight (> + 1SD) and obesity (> + 2SD) were defined using the World Health Organization child growth reference 2007. Chi-square test was used as the test of trend. Linear regression was used to examine the predictive power of independent variables in relation to BMI. Logistic regression was used to quantify the independent predictors for overweight and adjusted odds ratios (aOR) with 95% confidence intervals (CI) were obtained. All regression analyses were controlled for age and gender and statistical significance was considered at P < 0.05.
Results
Seventeen percent (95% CI 15.4-18.8) children were overweight and 7.5% (95% CI 6.5-8.7) were obese. Higher prevalence of obesity was observed among boys than girls (P = 0.028), however, there was no gender disparity in overweight prevalence. Prevalence of overweight showed a significantly increasing trend with grade (P < 0.001). Children living in the urban area with high socioeconomic status (SES) were significantly at risk for being overweight and obese (both P < 0.001) as compared to children living in the urban area with lower SES and rural children. Being in higher grade (aOR 2.39, 95% CI 1.17-4.90) and living in the urban area with higher SES (aOR 18.10, 95% CI 10.24-32.00) independently predicted the risk of being overweight.
Conclusion
Alarmingly rapid rise in overweight and obesity among Pakistani primary school children was observed, especially among the affluent urban population. The findings support the urgent need for National preventive strategy for childhood obesity and targeted interventions tailored to local circumstances with meaningful involvement of communities.
doi:10.1186/1471-2458-11-724
PMCID: PMC3195095  PMID: 21943029
6.  Severe obesity in children: prevalence, persistence and relation to hypertension 
Background
Newer approaches for classifying gradations of pediatric obesity by level of body mass index (BMI) percentage above the 95th percentile have recently been recommended in the management and tracking of obese children. Examining the prevalence and persistence of severe obesity using such methods along with the associations with other cardiovascular risk factors such as hypertension is important for characterizing the clinical significance of severe obesity classification methods.
Methods
This retrospective study was conducted in an integrated healthcare delivery system to characterize obesity and obesity severity in children and adolescents by level of body mass index (BMI) percentage above the 95th BMI percentile, to examine tracking of obesity status over 2–3 years, and to examine associations with blood pressure. Moderate obesity was defined by BMI 100-119% of the 95th percentile and severe obesity by BMI ≥120% × 95th percentile. Hypertension was defined by 3 consecutive blood pressures ≥95th percentile (for age, sex and height) on separate days and was examined in association with obesity severity.
Results
Among 117,618 children aged 6–17 years with measured blood pressure and BMI at a well-child visit during 2007–2010, the prevalence of obesity was 17.9% overall and was highest among Hispanics (28.9%) and blacks (20.5%) for boys, and blacks (23.3%) and Hispanics (21.5%) for girls. Severe obesity prevalence was 5.6% overall and was highest in 12–17 year old Hispanic boys (10.6%) and black girls (9.5%). Subsequent BMI obtained 2–3 years later also demonstrated strong tracking of severe obesity. Stratification of BMI by percentage above the 95th BMI percentile was associated with a graded increase in the risk of hypertension, with severe obesity contributing to a 2.7-fold greater odds of hypertension compared to moderate obesity.
Conclusion
Severe obesity was found in 5.6% of this community-based pediatric population, varied by gender and race/ethnicity (highest among Hispanics and blacks) and showed strong evidence for persistence over several years. Increasing gradation of obesity was associated with higher risk for hypertension, with a nearly three-fold increased risk when comparing severe to moderate obesity, underscoring the heightened health risk associated with severe obesity in children and adolescents.
doi:10.1186/1687-9856-2014-3
PMCID: PMC3976673  PMID: 24580759
Obesity; Children; Adolescents; Blood pressure
7.  Childhood obesity and overweight prevalence trends in England: evidence for growing socio-economic disparities 
International journal of obesity (2005)  2009;34(1):10.1038/ijo.2009.217.
Objective
Previous data indicate a rapidly increasing prevalence of obesity and overweight among English children and an emerging socioeconomic gradient in prevalence. The main aim of this study was to update prevalence trends among school-age children and assess the changing socioeconomic gradient.
Design
A series of nationally representative household-based health surveys conducted between 1997 and 2007 in England.
Subjects
15,271 white children (7880 boys) aged 5 to 10 years with measured height and weight.
Measurements
Height and weight were directly measured by trained fieldworkers. Overweight (including obesity) and obesity prevalence were calculated using the international body mass index cut-offs. Socioeconomic position (SEP) score was a composite score based on income and social class. Multiple linear regression assessed the prevalence odds with time point (1997/8, 2000/1, 2002/3, 2004/5, 2006/7) as the main exposure. Linear interaction terms of time by SEP were also tested for.
Results
There are signs that the overweight and obesity trend has levelled off from 2002/3 to 2006/7. The odds ratio (OR) for overweight in 2006/7 compared to 2002/3 was 0.99 (95% CI 0.88 to 1.11) and for obesity OR = 1.06 (0.86 to 1.29). The socioeconomic gradient has increased in recent years, particularly 2006/7. Compared to 1997/8, the 2006/7 age and sex-adjusted OR for overweight was 1.88 (1.52 to 2.33) in low SEP, 1.25 (1.04 to 1.50) in middle SEP, and 1.13 (0.86 to 1.48) in high SEP children.
Conclusion
Childhood obesity and overweight prevalence among school-age children in England has stabilised in recent years, but children from lower socio-economic strata have not benefited from this trend. There is an urgent need to reduce socio-economic disparities in childhood overweight and obesity.
doi:10.1038/ijo.2009.217
PMCID: PMC3865596  PMID: 19884892
Obesity; overweight; children; trends; England; socioeconomic status; socioeconomic position; income
8.  Prevalence, Disparities, and Trends in Obesity and Severe Obesity Among Students in the Philadelphia, Pennsylvania, School District, 2006–2010 
Introduction
Epidemic increases in obesity negatively affect the health of US children, individually and at the population level. Although surveillance of childhood obesity at the local level is challenging, height and weight data routinely collected by school districts are valuable and often underused public health resources.
Methods
We analyzed data from the School District of Philadelphia for 4 school years (2006–2007 through 2009–2010) to assess the prevalence of and trends in obesity and severe obesity among public school children.
Results
The prevalence of obesity decreased from 21.5% in 2006–2007 to 20.5% in 2009–2010, and the prevalence of severe obesity decreased from 8.5% to 7.9%. Both obesity and severe obesity were more common among students in grades 6 through 8 than among children in lower grades or among high school students. Hispanic boys and African American girls had the highest prevalence of obesity and severe obesity; Asian girls had much lower rates of obesity and severe obesity than any other group. Although obesity and severe obesity declined during the 4-year period in almost all demographic groups, the decreases were generally smaller in the groups with the highest prevalence, including high school students, Hispanic males, and African American females.
Conclusion
Although these data suggest that the epidemic of childhood obesity may have begun to recede in Philadelphia, unacceptably high rates of obesity and severe obesity continue to threaten the health and futures of many school children.
doi:10.5888/pcd9.120118
PMCID: PMC3475532  PMID: 22954057
9.  Trends of overweight and obesity, physical activity and sedentary behaviour in Czech schoolchildren: HBSC study 
Background: The decline of physical activity (PA) and the increased prevalence of overweight and obese children have been discussed worldwide. This study assessed the trends in the prevalence of overweight and obesity, PA and sedentary behaviour in Czech school-aged children. Methods: A cross-sectional questionnaire from the Czech Republic was administered in cycles in 2002, 2006 and 2010 under the Health Behaviour in School-Aged Children (HBSC) study. In the study, 14 219 children aged 11–15 years participated. Results: In comparison with 2002, there is a significant increase (P < 0.01) of obese and overweight boys in 2010. The same trend has been recorded in girls, except those in the 13-year-old group. There has been a significant decline (P < 0.05) in meeting PA recommendations in 11-year-old girls and boys and in 13-year-old girls when comparing the 2006 and 2002 data. In 2010, we found a non-significant increase or stagnation of the share of children meeting the PA recommendation compared with 2006. We found an increasing length of sedentary time for children. There were significant associations between>2 h being spent sitting by a TV or PC and consuming fruit and vegetables (negative associations) or sweets and sweetened lemonades (positive associations). Conclusions: An increasing percentage of obese or overweight children, increased sedentary time and a decline or stagnation of the proportion of children meeting recommendations for PA were found among Czech schoolchildren. Future research should evaluate PA recommendations with respect to gender, age and effective intervention approach to reduce the obesity incidence in childhood.
doi:10.1093/eurpub/ckt085
PMCID: PMC3966283  PMID: 23813709
10.  Secular trends in adiposity in Norwegian 9-year-olds from 1999-2000 to 2005 
BMC Public Health  2009;9:389.
Background
Due to the negative health consequences of childhood obesity monitoring trends in body mass and adiposity is essential. The purpose of this study was to describe secular trends in the prevalence of overweight and obesity among 9-year-old children, and to study changes in adiposity and fat distribution by investigating changes in waist circumference (WC) and skinfold thicknesses.
Methods
A total of 859 9-year-olds were included in two cross-sectional studies conducted in 1999-2000 and 2005. Measurements of body mass index (BMI; in kg/m2), WC and skinfold thicknesses were taken by trained investigators. The International Obesity Task Force cut-offs were used to define overweight and obese subjects.
Results
The overall prevalence of overweight (including obesity) did not change over the five year period. However, a shift may have occurred as the prevalence of overweight (including obesity) increased by 6.4% in girls and 5.5% in boys over the five year period. In both study periods, logistic regression analyses revealed that children of non-Western origin had 2 times higher odds of being overweight/obese than those of Western origin. However, neither the children of Western origin nor the children of non-Western origin showed a significant increase in the prevalence of overweight over the five-year period. No changes were observed for mean BMI, while a significant increase in WC was reported for both girls and boys, and an increase in all skinfold measurements was observed in girls only. Shifts in percentile distribution were observed for BMI, WC and sum of 4 skinfold thickness, however, the shift appeared to be faster in the upper end of the population distribution (p < 0.001 for interactions).
Conclusion
From 1999-2000 to 2005, there have been increases in 9-year-olds measures of adiposity even though the BMI did not change. The results indicate the need of a large-scale monitoring of adiposity, in addition to BMI, in children.
doi:10.1186/1471-2458-9-389
PMCID: PMC2765441  PMID: 19828037
11.  Severe Obesity Among Children in New York City Public Elementary and Middle Schools, School Years 2006–07 Through 2010–11 
Introduction
Although studies have shown that childhood obesity overall is on the decline among New York City (NYC) public school children, the prevalence of severe childhood obesity has not been studied.
Methods
We used height and weight measurements of 947,765 NYC public school students aged 5 to 14 years in kindergarten through 8th grade (K–8), from school years 2006–07 through 2010–11. We used age- and sex-specific body mass index (BMI) percentiles according to Centers for Disease Control and Prevention growth charts to define childhood obesity (BMI ≥ 95th percentile) and severe childhood obesity (BMI ≥120% of 95th percentile) and to identify biologically implausible values (BIV). Multivariable logistic models tested for trends in obesity and severe obesity prevalence. To evaluate misclassification, we recalculated prevalence estimates for the most recent school year (2010–11) including the student records identified as BIV who were also declared severely obese (BMI ≥ 120% of 95th percentile). We refer to this subgroup of BIVs as “high BIV.”
Results
Severe obesity among NYC public school students in grades K–8 decreased 9.5% from the 2006–07 school year (6.3%) to the 2010–11 school year (5.7%), and obesity decreased 5.5% (from 21.9% to 20.7%). The prevalence of severe obesity and obesity was highest among minority, poor, and male children. Severe obesity declined in prevalence among every subgroup, with the greatest effect among white students and wealthy students. Severe obesity prevalence increased with age, and obesity prevalence peaked among those aged 7 to 10 years. For the 2010–11 school year, including high BIVs increased severe obesity prevalence from 5.7% to 6.6% and increased obesity prevalence from 20.7% to 21.5%.
Conclusion
Among all subgroups of NYC public school children in grades K–8, the reduction in severe obesity was greater than the reduction in overall obesity. Efforts to decrease obesity in NYC have affected the severely obese; however, monitoring of this specific subgroup should continue because of differences in trends and greater health risks.
doi:10.5888/pcd11.130439
PMCID: PMC4093976  PMID: 25011000
12.  Individual- and School-Level Sociodemographic Predictors of Obesity Among New York City Public School Children 
American Journal of Epidemiology  2012;176(11):986-994.
To identify student- and school-level sociodemographic characteristics associated with overweight and obesity, the authors conducted cross-sectional analyses of data from 624,204 public school children (kindergarten through 12th grade) who took part in the 2007–2008 New York City Fitnessgram Program. The overall prevalence of obesity was 20.3%, and the prevalence of overweight was 17.6%. In multivariate models, the odds of being obese as compared with normal weight were higher for boys versus girls (odds ratio (OR) = 1.39, 95% confidence interval (CI): 1.36, 1.42), for black (OR = 1.11, 95% CI: 1.07, 1.15) and Hispanic (OR = 1.48, 95% CI: 1.43, 1.53) children as compared with white children, for children receiving reduced-price (OR = 1.17, 95% CI: 1.13, 1.21) or free (OR = 1.12, 95% CI: 1.09, 1.15) school lunches as compared with those paying full price, and for US-born students (OR = 1.54, 95% CI: 1.50, 1.58) as compared with foreign-born students. After adjustment for individual-level factors, obesity was associated with the percentage of students who were US-born (across interquartile range (75th percentile vs. 25th), OR = 1.10, 95% CI: 1.07, 1.14) and the percentage of students who received free or reduced-price lunches (across interquartile range, OR = 1.13, 95% CI: 1.10, 1.18). The authors conclude that individual sociodemographic characteristics and school-level sociodemographic composition are associated with obesity among New York City public school students.
doi:10.1093/aje/kws187
PMCID: PMC3626053  PMID: 23132672
child; obesity; overweight; physical fitness; schools
13.  Child Mortality Estimation: Estimating Sex Differences in Childhood Mortality since the 1970s 
PLoS Medicine  2012;9(8):e1001287.
Cheryl Sawyer uses new methods to generate estimates of sex differences in child mortality which can be used to pinpoint areas where these differences in mortality merit closer examination.
Introduction
Producing estimates of infant (under age 1 y), child (age 1–4 y), and under-five (under age 5 y) mortality rates disaggregated by sex is complicated by problems with data quality and availability. Interpretation of sex differences requires nuanced analysis: girls have a biological advantage against many causes of death that may be eroded if they are disadvantaged in access to resources. Earlier studies found that girls in some regions were not experiencing the survival advantage expected at given levels of mortality. In this paper I generate new estimates of sex differences for the 1970s to the 2000s.
Methods and Findings
Simple fitting methods were applied to male-to-female ratios of infant and under-five mortality rates from vital registration, surveys, and censuses. The sex ratio estimates were used to disaggregate published series of both-sexes mortality rates that were based on a larger number of sources. In many developing countries, I found that sex ratios of mortality have changed in the same direction as historically occurred in developed countries, but typically had a lower degree of female advantage for a given level of mortality. Regional average sex ratios weighted by numbers of births were found to be highly influenced by China and India, the only countries where both infant mortality and overall under-five mortality were estimated to be higher for girls than for boys in the 2000s. For the less developed regions (comprising Africa, Asia excluding Japan, Latin America/Caribbean, and Oceania excluding Australia and New Zealand), on average, boys' under-five mortality in the 2000s was about 2% higher than girls'. A number of countries were found to still experience higher mortality for girls than boys in the 1–4-y age group, with concentrations in southern Asia, northern Africa/western Asia, and western Africa. In the more developed regions (comprising Europe, northern America, Japan, Australia, and New Zealand), I found that the sex ratio of infant mortality peaked in the 1970s or 1980s and declined thereafter.
Conclusions
The methods developed here pinpoint regions and countries where sex differences in mortality merit closer examination to ensure that both sexes are sharing equally in access to health resources. Further study of the distribution of causes of death in different settings will aid the interpretation of differences in survival for boys and girls.
Please see later in the article for the Editors' Summary.
Editors' Summary
Background
In 2000, world leaders agreed to eradicate extreme poverty by 2015. To help track progress towards this global commitment, eight Millennium Development Goals (MDGs) were set. MDG 4, which aims to reduce child mortality, calls for a reduction in under-five mortality (the number of children who die before their fifth birthday) to a third of its 1990 level of 12 million by 2015. The under-five mortality rate is also denoted in the literature as U5MR and 5q0. Progress towards MDG 4 has been substantial, but with only three years left to reach it, efforts to strengthen child survival programs are intensifying. Reliable estimates of trends in childhood mortality are pivotal to these efforts. So, since 2004, the United Nations Inter-agency Group for Child Mortality Estimation (UN IGME) has used statistical regression models to produce estimates of trends in under-five mortality and infant mortality (death before age one year) from data about childbearing and child survival collected by vital registration systems (records of all births and deaths), household surveys, and censuses.
Why Was This Study Done?
In addition to estimates of overall childhood mortality trends, information about sex-specific childhood mortality trends is desirable to monitor progress towards MDG 4, although the interpretation of trends in the relative mortality of girls and boys is not straightforward. Newborn girls survive better than newborn boys because they are less vulnerable to birth complications and infections and have fewer inherited abnormalities. Thus, the ratio of infant mortality among boys to infant mortality among girls is greater than one, provided both sexes have equal access to food and medical care. Beyond early infancy, girls and boys are similarly vulnerable to infections, so the sex ratio of deaths in the 1–4-year age group is generally lower than that of infant mortality. Notably, as living conditions improve in developing countries, infectious diseases become less important as causes of death. Thus, in the absence of sex-specific differences in the treatment of children, the sex ratio of childhood mortality is expected be greater than one and to increase as overall under-five mortality rates in developing countries decrease. In this study, the researcher evaluated national and regional changes in the sex ratios of childhood mortality since the 1970s to investigate whether girls and boys have equal access to medical care and other resources.
What Did the Researcher Do and Find?
The researcher developed new statistical fitting methods to estimate trends in the sex ratio of mortality for infants and young children for individual countries and world regions. When considering individual countries, the researcher found that for 92 countries in less developed regions, the median sex ratio of under-five mortality increased between the 1970s and the 2000s, in line with the expected changes just described. However, the average sex ratio of under-five mortality for less developed regions, weighted according to the number of births in each country, did not increase between the 1970s and 2000s, at which time the average under-five mortality rate of boys was about 2% higher than that of girls. This discrepancy resulted from India and China—the two most populous developing countries—having sex ratios for both infant and under-five mortality that remained constant or declined over the study period and were below one in the 2000s, a result that indicates excess female mortality. In China, for example, infant mortality was found to be 12% higher for boys than for girls in the 1970s, but 24% lower for boys than for girls in the 2000s. Finally, although in the less developed regions (excluding India and China) girls went from having a slight survival disadvantage at ages 1–4 years in the 1970s, on average, to having a slight advantage in the 2000s, girls remained more likely to die than boys in this age group in several Asian and African countries.
What Do These Findings Mean?
Although the quality of the available data is likely to affect the accuracy of these findings, in most developing countries the ratio of male to female under-five mortality has increased since the 1970s, in parallel with the decrease in overall childhood mortality. Notably, however, in a number of developing countries—including several each in sub-Saharan Africa, northern Africa/western Asia, and southern Asia—girls have higher mortality than boys at ages 1–4 years, and in India and China girls have higher mortality in infancy. Thus, girls are benefitting less than boys from the overall decline in childhood mortality in India, China, and some other developing countries. Further studies are needed to determine the underlying reasons for this observation. Nevertheless, the methods developed here to estimate trends in sex-specific childhood mortality pinpoint countries and regions where greater efforts should be made to ensure that both sexes have equal access to health care and other important resources during early life.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001287.
This paper is part of a collection of papers on Child Mortality Estimation Methods published in PLOS Medicine
The United Nations Childrens Fund works for children's rights, survival, development, and protection around the world; it provides information on Millennium Development Goal 4, and its Childinfo website provides detailed statistics about child survival and health, including a description of the United Nations Inter-agency Group for Child Mortality Estimation; the 2011 UN IGME report Levels & Trends in Child Mortality is available
The World Health Organization also has information about Millennium Development Goal 4 and provides estimates of child mortality rates (some information in several languages)
Further information about the Millennium Development Goals is available
A 2011 report by the United Nations Department of Economic and Social Affairs entitled Sex Differentials in Childhood Mortality is available
doi:10.1371/journal.pmed.1001287
PMCID: PMC3429399  PMID: 22952433
14.  Overweight and obesity trends from 1974 to 2003 in English children: what is the role of socioeconomic factors? 
Archives of Disease in Childhood  2005;90(10):999-1004.
Aims: To examine the childhood overweight and obesity prevalence trends between 1974 and 2003 and to assess whether these trends relate to parental social class and household income.
Methods: A school based and a general population health survey: the National Study of Health and Growth in 1974, 1984, and 1994, and the Health Survey for England, yearly from 1996 to 2003. Participants were 14 587 white boys and 14 014 white girls aged 5–10 years. Overweight and obesity prevalence were calculated using UK specific as well as international body mass index (kg/m2) cut-offs. Socioeconomic status was measured using the Registrar General's social class; household income (1997 onwards only) was adjusted for household size.
Results: The prevalence of obesity (UK specific definition) in boys increased from 1.2% in 1984 to 3.4% in 1996–97 and 6.0% in 2002–03. In girls, obesity increased from 1.8% in 1984 to 4.5% in 1996–97 and 6.6% in 2002–03. Obesity prevalence has been increasing at accelerating rates in the more recent years. Children from manual social classes had marginally higher odds (OR 1.14, 95% CI 0.98 to 1.33) and children from higher income households had lower odds (OR 0.74, 95% CI 0.61 to 0.89) to be obese than their peers from non-manual class, and lower income households, respectively.
Conclusion: Childhood obesity is increasing rapidly into the 2000s in England and these increases are more marked among children from lower socioeconomic strata. There is an urgent need for action to prevent further increase in obesity among children.
doi:10.1136/adc.2004.068932
PMCID: PMC1720119  PMID: 15956046
15.  Prevalence of overweight and obesity and their associations with blood pressure among children and adolescents in Shandong, China 
BMC Public Health  2014;14(1):1080.
Background
Obesity and high blood pressure (BP) are public health problems all over the world. Some studies have reported a positive association between them in children and adolescents. The purpose of this study was to assess the prevalence of overweight and obesity and their associations with BP among school children and adolescents in Shandong, an important province in eastern China.
Methods
In 2011, we conducted a cross-sectional population-representative survey in Shandong, China. A total of 4 898 children and adolescents aged 6–17 years were randomly selected from 140 counties/districts using a multistage random cluster sampling. Weight, height and BP were measured by a trained physician or pediatrician, and information about age, gender and place of residence was obtained using questionnaires. Obesity and high BP were defined according to age- and gender-specific Chinese reference data for children.
Results
A total of 4 898 (100%) children and adolescents provided complete information. The prevalence of overweight, obesity and overweight plus obesity were 10.9%, 8.7% and 19.6%, respectively. Boys were more likely to be overweight or obese than girls (P < 0.05 for overweight; P < 0.001 for obesity). The prevalence of overweight plus obesity was highest among children aged 6–11 years (22.3%). BP and the prevalence of high BP increased with increasing body mass index (BMI). With age and sex adjusted, odds ratios (ORs) for high BP were [OR 2.2;95% CI 1.7–2.8) in overweight and [OR 3.6;95% CI 2.6–4.9] in obese children.
Conclusion
The representative survey confirms high prevalence of overweight and obesity among children and adolescents in Shandong. Childhood obesity is a strong risk factor for high BP. Intervention programs should be implemented to combat the growing obesity epidemic.
doi:10.1186/1471-2458-14-1080
PMCID: PMC4216350  PMID: 25326029
Prevalence; Overweight; Obesity; Adolescents; Blood pressure
16.  Early Onset of Overweight and Obesity among Low-Income 1- to 5-Year Olds in New York City 
Early-childhood obesity has reached epidemic proportions, particularly among low-income, minority, urban children. Understanding the progression of obesity prevalence rates from infancy through early childhood can inform public health efforts to combat this epidemic and create developmentally appropriate strategies. In this study, we assessed the prevalence of overweight and obesity among urban 1- to 5-year olds and estimated risk by age and gender. We surveyed the medical records of a random sample of 1,713 children seen at a New York City primary-care network. Outcome measures were weight-for-length for <2-year olds and body mass index for 2- to 5-year olds. Overweight was defined as percentiles ≥85% to <95%, obesity ≥95%. Analysis utilized chi-square, logistic regression, and z tests. Between 1 and 5 years of age, overweight increased 3.7% to 20.8% and obesity 7.5% to 29.8% (p < 0.01). Risk increased with age: compared with 1-year olds, 5-year olds were 8.2 times as likely (95% confidence interval (CI) = 5.5–12.21) to be overweight or obese. Boys were more likely to be obese than girls (adjusted odds ratio = 1.3; 95% CI = 1–1.64). Significant increases in overweight and obesity occurred between ages 1 and 3 years (overweight, 3.7% to 16%, p < 0.01; obesity, 7.5% to 30.2%, p < 0.01). Among urban children, more than half were overweight or obese by age 5. Overweight and obesity rates increased dramatically between the ages of 1 and 3 years. Interventions aimed at this age period may have the greatest impact at preventing childhood obesity.
doi:10.1007/s11524-008-9285-8
PMCID: PMC2443255  PMID: 18470622
Body mass index, BMI; Childhood obesity; Community health; Ethnic minorities; Prevalence
17.  The Pediatric Obesity Epidemic Continues Unabated in Bogalusa, Louisiana 
Pediatrics  2010;125(5):900-905.
Objectives
To examine 35-year trends in the prevalence of overweight and obesity among children and adolescents from Bogalusa, LA.
Patients and Methods
Height and weight were measured for 11,653 children and adolescents between 5 and 17 years of age in 8 cross-sectional surveys. The Bogalusa Heart Study contributed data from 1973–1994, and routine school screening provided 2008–2009 data. Trends in mean BMI, mean gender-specific BMI-for-age z-scores, prevalence of overweight/obesity (BMI ≥85th percentile), and prevalence of obesity (BMI ≥95th percentile) by age, race, and gender were examined.
Results
Since 1973–1974, the proportion of children and adolescents aged 5 to 17 years who are overweight (overweight plus obese) has more than tripled, from 14.2% to 48.4% in 2008–2009. Similarly, the proportion of obese children and adolescents has increased more than fivefold from 5.6% in 1973–1974 to 30.8% in 2008–2009. The prevalence of overweight or obesity, and secular changes, were similar across black and white boys and girls.
Conclusions
In semirural Bogalusa, the childhood obesity epidemic has not plateaued, and nearly half of children are now overweight or obese.
doi:10.1542/peds.2009-2748
PMCID: PMC3023706  PMID: 20368311
Overweight; obesity; trends; rural
18.  Overweight and Obesity Among Hawai‘i Children Aged 4 to 5 Years Enrolled in Public Schools in 2007–2008 and Comparison with a Similar 2002–2003 Cohort 
This assessment provides the most recent estimates of overweight and obesity among children 4 to 5 years old who were enrolled in public schools in the 2007–2008 school year, using data obtained from Student Health Records for 12,823 children, which represents 91% of the 14,070 children who were enrolled in kindergarten in 2007–2008. This assessment is a census of 4 to 5 year olds that entered public schools in Hawai‘i in 2007–2008 and represents approximately 38% of the total Hawai‘i population for those aged 4 to 5 years, since kindergarten is not a requirement. A limited data set with data on age, sex, height, and weight was used to calculate BMI (body mass index) percentiles. We compare this data with age and sex-specific BMI obtained from Student Health Records from 10,199 children aged 4 to 5 years entering public schools during 2002–2003. The results illustrate that like the 2002–2003 data (28.5%), over one in four (28.6%) of the children aged 4 to 5 years entering Hawai‘i public schools in 2007–2008 were either overweight or obese. Total proportions overweight and obese were persistently higher (32.5% or more in both 2002–2003 and 2007–2008) in some specific school complexes on O‘ahu as well as in some rural and Neighbor Island school complexes. Physicians, public health and school health professionals, advocates, schools, and communities should be vigilant about this persistent problem and seek to implement practices to combat overweight and obesity. In addition, the use of Student Health Records for on-going pediatric obesity surveillance should be explored more fully.
PMCID: PMC3727572  PMID: 23900736
19.  Decreasing Prevalence of Obesity Among Young Children in Massachusetts From 2004 to 2008 
Pediatrics  2012;129(5):823-831.
OBJECTIVE:
To examine whether the obesity prevalence is increasing, level, or decreasing among young US children (aged <6 years) in the past decade; and to compare regional data to those of 2 national databases.
METHODS:
We analyzed data from 108 762 well-child visits (36 827 children) at a multisite pediatric practice in eastern Massachusetts during 1999–2008. By using the Centers for Disease Control and Prevention 2000 gender-specific growth charts, we defined obesity as weight-for-length ≥95th percentile for children aged <24 months and BMI ≥95th percentile for children aged 24 to <72 months. By using multivariable logistic regression, we estimated gender-specific obesity trends in 2 separate periods, 1999–2003 and 2004–2008, adjusting for age group, race/ethnicity, health insurance, and practice site.
RESULTS:
From 1999 to 2003, the obesity prevalence was fairly stable among both boys and girls. From 2004 to 2008, the obesity prevalence substantially decreased among both boys and girls. The decline in obesity prevalence during 2004–2008 was more pronounced among children insured by non-Medicaid health plans than among those insured by Medicaid.
CONCLUSIONS:
Among children aged <6 years at this multisite pediatric practice, obesity prevalence decreased during 2004–2008, which is in line with national data showing no increase in prevalence during this time period. The smaller decrease among Medicaid-insured children may portend widening of socioeconomic disparities in childhood obesity.
doi:10.1542/peds.2011-1833
PMCID: PMC3340588  PMID: 22529276
obesity; BMI; child; infant; prevalence; trends; epidemiology
20.  Nutritional status and risk factors of overweight and obesity for children aged 9–15 years in Chengdu, Southwest China 
BMC Public Health  2012;12:636.
Background
Obesity is widespread in the world including developing countries. However malnutrition in poor areas is still a serious problem. Few investigations, especially in a large sample, have been performed in Western area of China. This study aimed to evaluate the nutritional status of school children aged 9–15 years in large Southwest city of China, and identify the differential impact of aberrant birth categories and family history of obesity related disease on childhood overweight and obesity development.
Methods
A multistage random cluster sampling was performed to evaluate the prevalence of thinness, overweight and obesity, which were defined by the new age-, sex-, specific BMI reference developed by World Health Organization (WHO) (2007). And then a frequency matched case–control study was performed to identify the risk factors of overweight and obesity.
Results
7,194 children (3,494 boys, 3,700 girls) were recruited, and 1,282 (17.8%) had excess bodyweight (14.5% overweight, 3.3% obesity). The combined prevalence gradually decreased with age, and were more prevalent among boys than girls (P <0.05). Meanwhile 6.3% were found thinness and there were little differences in genders (P >0.05). Preterm large for gestational age (OR = 2.746), maternal history of obesity related disease (OR = 1.713), paternal history of obesity related disease (OR = 1.583), preterm appropriate for gestational age (OR = 1.564), full term small for gestational age (OR = 1.454) and full term large for gestational age (OR = 1.418) were recognized as significant risk factors in the multivariate regression analysis (P <0.05).
Conclusions
While overweight and obesity was dramatically spreading, malnutrition still remained a serious problem. This unmatched nutritional status should be emphasized in backward cities of China. Children born of both preterm and LGA, whose parents particularly mothers had a history of obesity related disease, should be emphatically intervened as early as possible.
doi:10.1186/1471-2458-12-636
PMCID: PMC3488485  PMID: 22892270
21.  TV Viewing and Physical Activity Are Independently Associated with Metabolic Risk in Children: The European Youth Heart Study 
PLoS Medicine  2006;3(12):e488.
Background
TV viewing has been linked to metabolic-risk factors in youth. However, it is unclear whether this association is independent of physical activity (PA) and obesity.
Methods and Findings
We did a population-based, cross-sectional study in 9- to 10-y-old and 15- to 16-y-old boys and girls from three regions in Europe (n = 1,921). We examined the independent associations between TV viewing, PA measured by accelerometry, and metabolic-risk factors (body fatness, blood pressure, fasting triglycerides, inverted high-density lipoprotein (HDL) cholesterol, glucose, and insulin levels). Clustered metabolic risk was expressed as a continuously distributed score calculated as the average of the standardized values of the six subcomponents. There was a positive association between TV viewing and adiposity (p = 0.021). However, after adjustment for PA, gender, age group, study location, sexual maturity, smoking status, birth weight, and parental socio-economic status, the association of TV viewing with clustered metabolic risk was no longer significant (p = 0.053). PA was independently and inversely associated with systolic and diastolic blood pressure, fasting glucose, insulin (all p < 0.01), and triglycerides (p = 0.02). PA was also significantly and inversely associated with the clustered risk score (p < 0.0001), independently of obesity and other confounding factors.
Conclusions
TV viewing and PA may be separate entities and differently associated with adiposity and metabolic risk. The association between TV viewing and clustered metabolic risk is mediated by adiposity, whereas PA is associated with individual and clustered metabolic-risk indicators independently of obesity. Thus, preventive action against metabolic risk in children may need to target TV viewing and PA separately.
A study of over 1,900 European children showed that TV viewing and physical activity in children are separately associated with obesity and metabolic risk.
Editors' Summary
Background.
Childhood obesity is a rapidly growing problem. Twenty-five years ago, overweight children were rare. Now, 155 million of the world's children are overweight, and 30–45 million are obese. Both conditions are diagnosed by comparing a child's body mass index (BMI; weight divided by height squared) with the average BMI for their age and sex. Being overweight during childhood is worrying because it is one of the so-called metabolic-risk factors that increase the chances of developing diabetes, heart problems, or strokes later in life. Other metabolic-risk factors are fatness around the belly, blood-fat disorders, high blood pressure, and problems with how the body uses insulin and blood sugar. Until recently, like obesity, these other metabolic-risk factors were seen only in adults, but now they are becoming increasingly common in children. In the US, 1 in 20 adolescents has metabolic syndrome—three or more of these risk factors. Environmental and behavioural changes have probably contributed to the increase in metabolic syndrome in children. As a group, they tend to be less physically active nowadays and they eat bigger portions of energy-dense foods more often. Increased TV viewing during childhood (and the use of other media such as computer games) has also been linked to increased obesity and to poorer health as an adult.
Why Was This Study Done?
One popular theory is that TV viewing may affect obesity and other metabolic-risk factors by displacing PA. Instead of playing in the yard after school, the theory suggests, children laze about in front of the TV. However, there is limited evidence to support this idea, and health professionals need to know whether TV viewing and PA are related, and how they affect metabolic-risk factors, in order to improve children's health. In this study, the researchers examined the associations between TV viewing, PA, and metabolic-risk factors in European children.
What Did the Researchers Do and Find?
The researchers enrolled nearly 2,000 children in two age groups from three areas in Europe. They measured the children's height and weight, estimated how fat they were by measuring skin fold thickness, measured their blood pressure, and examined the levels of glucose, insulin, and different fats in their blood. The children completed a computer questionnaire about the lengths of time for which they watched TV and how often they ate while doing so, and their PA was measured using a device called an accelerometer that each child wore for four days. When these data were analyzed statistically, the researchers found that TV viewing was slightly associated with clustered metabolic risk (the average of the individual metabolic-risk factors). This association was due to an association between TV viewing and obesity—the children who watched most TV tended to be the fattest children. However, TV viewing was not related to PA. The most active children were not necessarily those who watched least TV. Most importantly, PA was related to all individual risk factors except for obesity and with clustered metabolic risk. These associations were independent of obesity.
What Do These Findings Mean?
These results suggest that TV viewing does not damage children's health by displacing PA as popularly believed. The finding that the association between TV viewing and clustered metabolic-risk factors is mediated by obesity suggests that targeting behaviours like eating while watching TV might be a good way to improve children's health. Indeed, the researchers provide some evidence that eating while watching TV is associated with being overweight, but the results of this post hoc analysis—one that was not planned in advance—need to be confirmed. Another limitation of the study is the possibility that the children inaccurately reported their TV watching habits. Also, because measurements of metabolic-risk factors were made only once, it is impossible to say whether TV viewing or lack of PA actually causes an increase in metabolic-risk factors.
Nevertheless, these results strongly suggest that promoting PA is beneficial in relation to metabolic-risk factors, but less so in relation to obesity in childhood. TV viewing and PA should be treated as separate targets in programs designed to reverse the obesity and metabolic-syndrome epidemic in children.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/doi:10.1371/journal.pmed.0030488.
US Centers for Disease Control and Prevention, information on overweight and obesity
International Obesity Taskforce, information on obesity and its prevention, particularly in childhood
Global Prevention Alliance, details of international efforts to halt the obesity epidemic and its associated chronic diseases
American Heart Association, information for patients and professionals on metabolic syndrome and children's health
doi:10.1371/journal.pmed.0030488
PMCID: PMC1705825  PMID: 17194189
22.  Prevalence of overweight and obesity in a provincial population of Canadian preschool children 
Background
More and more school-aged children in Canada and elsewhere are becoming overweight or obese. Many countries are now reporting a similar trend among preschool children. However, little information is available on the prevalence of overweight and obesity among preschool children in Canada. In addition, available data are based on reported rather than measured heights and weights. We conducted this study to determine the prevalence of overweight and obesity, using measured heights and weights, in the 1997 cohort of children aged 3–5 years born in Newfoundland and Labrador.
Methods
We calculated the body mass indices (BMIs) using heights and weights measured by public health nurses during the province-wide Preschool Health Check Program conducted between October 2000 and January 2003. Descriptive data on the children's BMIs and prevalence estimates were generated and analyzed by sex and age with the use of the classification system recommended by the International Obesity Task Force.
Results
Data were available for 4161 of the 5428 children born in 1997; boys and girls were equally represented (50.1% and 49.9% respectively). Overall, 25.6% of the preschool children in the cohort were overweight or obese. The rates did not differ significantly by sex or age group
Interpretation
These results indicate that a high proportion of children aged 3–5 years in Newfoundland and Labrador are overweight or obese. It appears that prevention measures should begin before the age of 3 years.
doi:10.1503/cmaj.1040075
PMCID: PMC490073  PMID: 15289421
23.  Prevalence of Obesity in Elementary Schools in Mardin, South-Eastern of Turkey: A Preliminary Study 
Balkan medical journal  2012;29(4):424-430.
Objective:
This research determines the frequency of obesity among primary school-aged children and evaluates the relationship between obesity and family and environmental factors.
Material and Methods:
Three thousand four hundred sixty students, aged 6–15 years in three primary schools in Mardin city center were taken into the study. Information about eating habits and family-environmental factors were obtained by questionnaire. For each student we calculated the body mass index (BMI) and the ≥97 percentile was defined as obese, and between 85–97th percentile as overweight. These values were calculated with the SPSS statistical program. Chi-square and t-tests were used for analysis. p<0.05 was considered statistically significant.
Results:
48.2% of the students were female. In the assessment of body mass index (BMI) the overweight rate for children was 15.78%, the obese rate was 10.57%. The prevalence of obesity according to gender was 9.05% for girls and 11.97% for boys (p<0.01). The mean BMI of the girls in the age group 13–15 is higher than in males of the same age. Those in the higher socio-economic group had a higher prevalence of obesity (p<0.01). Paternal obesity affected child obesity (p<0.01). Children who eat irregular meals (p=0.05), watch more than 2 hours per day TV (p=0.03), were breastfed for less than 6 months (p<0.05) and the mothers’ obesity (p<0.05) were found to have a significantly higher prevalence of obesity.
Conclusion:
Obesity is increasing throughout the world as a health problem. Being obese in childhood and having obese parent(s) are two of the risk factors of being obese in adulthood. Persistence of obesity into adulthood is the most serious aspect of the problem. The therapeutic success rate in obesity is unfortunately not high. Therefore, a preventive strategy involving early identification of those at risk by incorporating body mass assessments to routine childhood growth assessment appears to be the most prudent strategy.
doi:10.5152/balkanmedj.2012.051
PMCID: PMC4115880  PMID: 25207047
Childhood obesity; prevalence; body mass index; Mardin; Turkey
24.  PERCEPTION OF BODY WEIGHT AMONG SAUDI SCHOOL CHILDREN 
Objectives:
The objectives of this study were to explore the perception of body weight among students in schools in Jeddah City and identify the main determinants of self-perceived obesity, weight management goals and practices.
Material and Methods:
Data were collected from a sample of Saudi school children of 42 boys’ and 42 girls’ schools in Jeddah city during the month of April 2000. Personal interviews were conducted to collect data on socio-demographic factors, food choices, perception of body weight, weight management goals and weight management practices, as well as the actual measurement of weight and height. Students were asked about their perception of their body weight [responses included: very underweight (thin), slightly underweight, about right weight, slightly overweight and grossly overweight (obese)]. Proportion, prevalence and 95% confidence intervals were calculated. Multiple logistic regression models were fitted to calculate the adjusted odds ratio (OR) for an attempt to lose weight and weight management practices.
Results:
The distribution of self-perception of body size was nearly similar to the measured body mass index (BMI) classification except for the overweight students, where 21.3% perceived themselves, as slightly overweight and 5.5% as very overweight although 13.4% were actually overweight and 13.5% were obese by BMI standards. Approximately half the students took at least 3 pieces of fruit or fruit juice servings, and a third ate at least 4 vegetable servings per day. A third of the students managed to lose weight. This coincides with the proportion of those actually overweight and obese. Around 28.0% of the students ate less food, fat or calories, 31.0% took exercise and 17.6% were engaged in vigorous exercise to lose weight or prevent weight gain. Staying for at least 24 hours without food which is a potentially harmful means of weight control was practiced by 10.0% of students. Females were less likely than males to be overweight and obese but more likely to perceive themselves as grossly overweight and more likely to try to lose weight. Factors associated with efforts to lose weight by eating less fat or fewer calories were older age, high social class, being actually obese and perceiving oneself as being obese. Staying for at least 24 hours without eating was mainly practiced by females, older age groups, and the actually obese. Exercise was done mainly by the older age groups, those with educated and highly educated mothers, obese and perceiving oneself as being obese. Vigorous exercise was mainly performed by males, younger age groups, taking < 3 pieces of fruit or fruit juice servings per day, eating < 4 vegetable servings per day, and those perceiving themselves as obese.
Conclusion:
Overweight and obesity are prevalent among our youth and not all obese have a correct image of their body size. Highly recommended are intervention programs of education on nutrition starting in childhood through school age to promote and ensure healthy food choices, improve student's awareness of ideal body size and clinical obesity, encourage physical exercise but discourage potentially harmful weight control measures.
PMCID: PMC3430166  PMID: 23008679
Overweight; perceived obesity; diet; physical activity; weight management; children; adolescents
25.  Longitudinal Study of Body Weight Changes in Children: Who is Gaining and Who is Losing Weight 
Obesity (Silver Spring, Md.)  2010;19(3):667-670.
Cross-sectional studies have reported significant temporal increases in prevalence of childhood obesity in both genders and various racial groups, but recently the rise has subsided. Childhood obesity prevention trials suggest that, on average, overweight/obese children lose body weight and non-overweight children gain weight. This investigation tested the hypothesis that overweight children lose body weight/fat and non-overweight children gain body weight/fat using a longitudinal research design that did not include an obesity prevention program. The participants were 451 children in 4th to 6th grades at baseline. Height, weight, and body fat were measured at Month 0 and Month 28. Each child’s body mass index (BMI) percentile score was calculated specific for their age, gender and height. Higher BMI percentile scores and percent body fat at baseline were associated with larger decreases in BMI and percent body fat after 28 months. The BMI percentile mean for African-American girls increased whereas BMI percentile means for white boys and girls and African-American boys were stable over the 28 month study period. Estimates of obesity and overweight prevalence were stable because incidence and remission were similar. These findings support the hypothesis that overweight children tend to lose body weight and non-overweight children tend to gain body weight.
doi:10.1038/oby.2010.221
PMCID: PMC3026913  PMID: 20885393
childhood obesity; longitudinal study; prevalence; incidence; remission

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