Etiology Of Childhood Obesity Research Articles

An observational approach to testing bi-directional parent–child interactions as influential to child eating and weight

Obesity among children has been on the rise globally for the past few decades. Previous research has centred mainly on self/parent-reported measures examining only uni-directional parental feeding styles and practices. Recent discussions in the literature have raised the importance of bi-directional parent–child interactions in influencing children's weight status. The aims of this paper are to highlight the importance of an observational approach when investigating positive bi-directional parent–child interactions during mealtimes and to outline how these interactions may be linked to positive child eating and weight outcomes. We examine the current literature on self-reported parental patterns and argue for the influential roles of responsiveness, affect and parental control dimensions within the parent–child dyad. Information about the ways in which the parent and the child can influence each other on these dimensions, as observed in parent–child interactions around food, is likely to provide greater insights into the aetiology of childhood obesity.

Multilevel predictors of adolescent physical activity: a longitudinal analysis.

BackgroundTo examine how factors from a social ecologic model predict physical activity (PA) among adolescents using a longitudinal analysis.MethodsParticipants in this longitudinal study were adolescents (ages 10-16 at baseline) and one parent enrolled in the Transdisciplinary Research on Energetics and Cancer-Identifying Determinants of Eating and Activity (TREC-IDEA) and the Etiology of Childhood Obesity (ECHO). Both studies were designed to assess a socio-ecologic model of adolescent obesity risk. PA was collected using ActiGraph activity monitors at two time points 24 months apart. Other measures included objective height and weight, adolescent and parent questionnaires on multilevel psychological, behavioral and social determinants of PA, and a home PA equipment inventory. Analysis was conducted using SAS, including descriptive characteristics, bivariate and stepped multivariate mixed models, using baseline adjustment. Models were stratified by gender.ResultsThere were 578 adolescents with complete data. Results suggest few statistically significant longitudinal associations with physical activity measured as minutes of MVPA or total counts from accelerometers. For boys, greater self-efficacy (B = 0.75, p = 0.01) and baseline MVPA (B = 0.55, p < 0.01) remained significantly associated with MVPA at follow-up. A similar pattern was observed for total counts. For girls, baseline MVPA (B = 0.58, p = 0.01) and barriers (B = -0.32, p = 0.05) significantly predicted MVPA at follow-up in the full model. The full multilevel model explained 30% of the variance in PA among boys and 24% among girls.ConclusionsPA change in adolescents is a complex issue that is not easily understood. Our findings suggest early PA habits are the most important predictor of PA levels in adolescence. Intervention may be necessary prior to middle school to maintain PA through adolescence.

Parenting Style and Child Feeding Practices: Potential Mitigating Factors in the Etiology of Childhood Obesity

Childhood obesity is a substantial health problem that disproportionately affects youth of all ages, particularly those from racial/ethnic minorities in the United States ( 1 Ogden C.L. Carroll M.D. Curtin L.R. Lamb M.M. Flegal K.M. Prevalence of high body mass index in US children and adolescents, 2007-2008. JAMA. 2010; 303: 242-249 Google Scholar ). According to the most recent National Health and Nutrition Examination Survey (2007-2008), among children who were age 2 through 5 years, the prevalence of body mass index (BMI) at or more than the 95th percentile for age and sex was 9.1% among non-Hispanic white children, 11.4% among non-Hispanic black children, and 13.7% among Hispanic children ( 1 Ogden C.L. Carroll M.D. Curtin L.R. Lamb M.M. Flegal K.M. Prevalence of high body mass index in US children and adolescents, 2007-2008. JAMA. 2010; 303: 242-249 Google Scholar ). Local and regional differences in obesity prevalence have been noted, as in the accompanying article by Acharya and colleagues, who found the highest rates of obesity among white preschool-aged children in a southern US population ( 2 Acharya K. Feese M. Franklin F. Kabagambe E.K. Body mass index and dietary intake among Head Start children and caregivers. J Am Diet Assoc. 2011; 111: 1314-1321 Google Scholar ). Published data suggest that the racial/ethnic disparities in obesity prevalence take root early in childhood and may persist into later childhood ( 1 Ogden C.L. Carroll M.D. Curtin L.R. Lamb M.M. Flegal K.M. Prevalence of high body mass index in US children and adolescents, 2007-2008. JAMA. 2010; 303: 242-249 Google Scholar , 2 Acharya K. Feese M. Franklin F. Kabagambe E.K. Body mass index and dietary intake among Head Start children and caregivers. J Am Diet Assoc. 2011; 111: 1314-1321 Google Scholar ). J. Stang is an associate professor, School of Public Health, Division of Epidemiology and Community Health, University of Minnesota, Minneapolis. K. A. Loth is a doctoral candidate, School of Public Health, Division of Epidemiology and Community Health, University of Minnesota, Minneapolis.

The metabolic activity of gut microbiota in obese children is increased compared with normal-weight children and exhibits more exhaustive substrate utilization

Objective:The gut microbiota contribute otherwise impossible metabolic functions to the human host. Shifts in the relative proportions of gut microbial communities in adults have been correlated with intestinal disease and have been associated with obesity. The aim of this study was to elucidate differences in gut microbial compositions and metabolite concentrations of obese versus normal-weight children.Materials and methods:Fecal samples were obtained from obese (n=15; mean body mass index (BMI) s.d. score=1.95) and normal-weight (n=15; BMI s.d. score=−0.14) Swiss children aged 8–14 years. Composition and diversity of gut microbiota were analyzed by qPCR and temperature gradient gel electrophoresis (TGGE).Results:No significant quantitative differences in gut microbiota communities of obese and normal-weight children were identified. Microbial community profiling by TGGE revealed a high degree of both intra- and intergroup variation. Intergroup comparison of TGGE profiles failed to identify any distinct populations exclusive to either obese or normal-weight children. High-pressure liquid chromatography analysis identified significantly higher (P<0.05) concentrations of short-chain fatty acids (SCFA) butyrate and propionate in obese versus normal-weight children. Significantly lower concentrations of intermediate metabolites were detected in obese children, suggesting exhaustive substrate utilization by obese gut microbiota.Conclusions:Our results indicate that a dysbiosis may be involved in the etiology of childhood obesity. In turn, aberrant and overactive metabolic activity within the intestine could dictate survival or loss of individual microbial communities, leading to the altered population ratios previously identified in adult obesity.

Lifestyle Risk Factors for Childhood Obesity

Background: this study was designed to assess the role of lifestyle and nutritional factors in the aetiology of childhood obesity. Methods: the study was carried out among two study populations of children aged 5-years ( n=206) and 9 years of age ( n=230). the children underwent standard anthropomorphic measurements that were correlated to the social status of the family, physical activity habits and nutritional factors. Results: the prevalence of childhood overweight-obesity in 5-year-old Maltese children was 28.8% in boys and 32.7% in girls; 48.9% and 45.1% respectively at 9 years of age. there was no apparent relationship between childhood obesity and the socioeco - nomic status of the family, but a definite statistically significant negative correlation was noted with breastfeeding in the 5-year-old children. the study suggested a possible positive relationship between childhood obesity and an increase mean passive activity time with a corresponding negative association to mean active physical activity and sleeping times. Obese children appeared to be eating more energy-dense food than their counterparts, though there seems to be an attempt to control for the increased weight by reducing the intake of sweets and snacks. Conclusions: the study suggests that the combination of decreased physical activity and increased energy-dense foods may be contributory towards the development of childhood obesity.

Early metabolic imprinting as a determinant of childhood obesity

AimsChildhood obesity has seen an alarming increase in recent decades. This study was designed to assess the role of family history and perinatal programming in the aetiology of childhood obesity in a population known to have a high risk of developing metabolic syndrome. MethodologyThe study was carried out among two study populations of children. The first was a population of 206 mixed-gender 5-year-old children; the second of 230 mixed-gender 9-year-old children. The children underwent standard anthropomorphic measurements that were correlated to family history of metabolic syndrome-related illness, the child’s birth weight and a history of breastfeeding in early infant life. ResultsNo statistically significant correlation was noted with a family history of metabolic syndrome; but a definite (P=0.04) negative correlation was noted with breastfeeding in the 5-year-old children. Children of low birth weight appeared to retain a lower body weight at five years of age than their higher birth weight counterparts (P=0.002). The pattern changed to suggest a U-shaped distribution of obesity among the various birth weight groups of children, though statistical significance was noted only for the macrosomic group (P=0.002). ConclusionsThe study confirms the importance of intrauterine and early infant nutrition towards the development of childhood and later obesity. Children of low or high birth weight should be considered at risk and parents are advised actively regarding health lifestyle and nutrition options.

Comment on: Measurement of Resting Energy Expenditure in Healthy Children

Background: The role that the components of energy expenditure play in the etiology of childhood obesity has highlighted the need for greater accuracy and standardized protocols for the measurement of resting energy expenditure (REE). However, protocols used to assess REE in children are varied, and consensus on a suitable method for measuring REE in children has not been reached. This study was undertaken to determine the effect of measurement time and measurement device (mask or mouthpiece) on REE in healthy children. Design: Following a 12‐hour fast and abstinence from exercise, 23 children (age, 7–12 years) completed two 35‐minute protocols: one with a face mask and the other with a mouthpiece/noseclip. Energy expenditure was measured continuously via indirect calorimetry, while device acceptability was assessed using a 6‐point comfort rating scale. Results: Repeated measures ANOVA indicated that there was no significant difference in REE when measured after 10, 15, 20, or 25 minutes of rest compared to 30 minutes for either the mask or mouthpiece/noseclip (REE range, 1371–1460 kcal/d). Examination of the percentage coefficient of variation (CV) in energy expenditure for each time period by device showed that the least variation existed after 20 minutes of measurement using the mask (CV 6%). Paired t test analysis indicated significantly less discomfort when wearing the mask compared to the mouthpiece/noseclip. Conclusion: It would appear that a 20‐minute protocol using a mask may increase compliance and prove to be a more practical protocol for measuring REE in children.(JPEN J Parenter Enteral Nutr. 2009;33:640‐645)

Measurement of Resting Energy Expenditure in Healthy Children

The role that the components of energy expenditure play in the etiology of childhood obesity has highlighted the need for greater accuracy and standardized protocols for the measurement of resting energy expenditure (REE). However, protocols used to assess REE in children are varied, and consensus on a suitable method for measuring REE in children has not been reached. This study was undertaken to determine the effect of measurement time and measurement device (mask or mouthpiece) on REE in healthy children. Following a 12-hour fast and abstinence from exercise, 23 children (age, 7-12 years) completed two 35-minute protocols: one with a face mask and the other with a mouthpiece/noseclip. Energy expenditure was measured continuously via indirect calorimetry, while device acceptability was assessed using a 6-point comfort rating scale. Repeated measures ANOVA indicated that there was no significant difference in REE when measured after 10, 15, 20, or 25 minutes of rest compared to 30 minutes for either the mask or mouthpiece/noseclip (REE range, 1371-1460 kcal/d). Examination of the percentage coefficient of varia tion (CV) in energy expenditure for each time period by device showed that the least variation existed after 20 minutes of measurement using the mask (CV 6%). Paired t test analysis indicated significantly less discomfort when wearing the mask compared to the mouthpiece/noseclip. It would appear that a 20-minute protocol using a mask may increase compliance and prove to be a more practical protocol for measuring REE in children.

Nutrient Adequacy and Diet Quality in Non-Overweight and Overweight Hispanic Children of Low Socioeconomic Status: The Viva la Familia Study

Objective The role of diet quality and nutrient adequacy in the etiology of childhood obesity is poorly understood. The specific aims of these analyses were to assess overall diet quality and nutrient adequacy, and test for association between weight status and diet in children from low socioeconomic status (SES) Hispanic families at high risk for obesity. Design A cross-sectional study design was used to assess dietary intake in low-SES Hispanic children with and without overweight who were enrolled in the Viva la Familia Study. Multiple-pass 24-hour dietary recalls were recorded on two random, weekday occasions. Diet quality was evaluated according to the Dietary Guidelines for Americans. Nutrient adequacy was assessed using z scores based on estimated average requirement or adequate intake. Subjects/setting The study included 1,030 Hispanic children and adolescents, aged 4 to 19 years, in Houston, TX, who participated between November 2000 and August 2004. Statistical analysis STATA software (version 9.1, 2006, STATA Corp, College Station, TX) was used for generalized estimating equations and random effects regression. Results Diet quality did not adhere to the Dietary Guidelines for Americans for fat, cholesterol, saturated fatty acids, fiber, added sugar, and sodium. Although energy intake was significantly higher in children with overweight, food sources, diet quality, macro- and micronutrient composition were similar between non-overweight and overweight children. Relative to estimated average requirements or adequate intake levels, mean nutrient intakes were adequate (70% to 98% probability) in the children without and with overweight, except for vitamins D and E, pantothenic acid, calcium, and potassium, for which z scores cannot be interpreted given the uncertainty of their adequate intake levels. Conclusions Whereas the diets of low-SES Hispanic children with and without overweight were adequate in most essential nutrients, other components of a healthful diet, which promote long-term health, were suboptimal. Knowledge of the diets of high-risk Hispanic children will inform nutritional interventions and policy.

Does parenting affect children's eating and weight status?

BackgroundWorldwide, the prevalence of obesity among children has increased dramatically. Although the etiology of childhood obesity is multifactorial, to date, most preventive interventions have focused on school-aged children in school settings and have met with limited success. In this review, we focus on another set of influences that impact the development of children's eating and weight status: parenting and feeding styles and practices. Our review has two aims: (1) to assess the extent to which current evidence supports the hypothesis that parenting, via its effects on children's eating, is causally implicated in childhood obesity; and (2) to identify a set of promising strategies that target aspects of parenting, which can be further evaluated as possible components in childhood obesity prevention.MethodsA literature review was conducted between October 2006 and January 2007. Studies published before January 2007 that assessed the association between some combination of parenting, child eating and child weight variables were included.ResultsA total of 66 articles met the inclusion criteria. The preponderance of these studies focused on the association between parenting and child eating. Although there was substantial experimental evidence for the influence of parenting practices, such as pressure, restriction, modeling and availability, on child eating, the majority of the evidence for the association between parenting and child weight, or the mediation of this association by child eating, was cross-sectional.ConclusionTo date, there is substantial causal evidence that parenting affects child eating and there is much correlational evidence that child eating and weight influence parenting. There are few studies, however, that have used appropriate meditational designs to provide causal evidence for the indirect effect of parenting on weight status via effects on child eating. A new approach is suggested for evaluating the effectiveness of intervention components and creating optimized intervention programs using a multiphase research design. Adoption of approaches such as the Multiphase Optimization Strategy (MOST) is necessary to provide the mechanistic evidence-base needed for the design and implementation of effective childhood obesity prevention programs.

Gene-diet interactions in childhood obesity: paucity of evidence as the epidemic of childhood obesity continues to rise.

Childhood obesity is growing rapidly worldwide. Although there have been enormous advances in the genetic underpinnings of obesity in recent years, the pathways that lead to obesity are still not completely understood. One of the ongoing challenges is the lack of a comprehensive definition of the obese phenotype that encompasses intermediary phenotypic expressions of biological and behavioral nature. Interactions between genetic and environmental factors, including nutrient exposures and dietary behaviors, can influence the development of the obese phenotype. Specifically, genes play a decisive role in the etiology of childhood obesity under the permissive circumstances of an obesogenic environment (increase in energy intake with a decrease in physical activity). Like many diseases, the causes of obesity are complex and their investigation requires novel approaches. Given the many contributors to obesity (weight gain, weight loss, weight maintenance, variability in body composition), as well as the dynamic nature of this issue, genomic tools must continue to be employed to evaluate all dimensions of the obesity phenotype, such as biochemical characteristics, susceptibility markers, nutrient intake, feeding practices and gene-environment interactions. Fundamental knowledge of the types of genes involved and available gene-diet interaction studies in children's obesity are reviewed. Although there is a paucity of existing literature in this specific domain of childhood obesity, ongoing investigations utilizing large cohorts have potential for providing the knowledge needed for targeted interventions in the future.

The Gene-Diet Attica Investigation on childhood obesity (GENDAI): overview of the study design

There is limited evidence on the role of genetic and environmental factors in the etiology of childhood obesity, a major health problem worldwide. The Gene-Diet Attica Investigation on childhood obesity (GENDAI) evaluates the contributions to and pivotal interactions of genetic, dietary and physical activity variables on children's weight. We describe the design, methodology, and present preliminary data. So far, 920 participants have been enrolled and the final projected sample is 1000 fifth- and sixth-grade students from selected elementary schools in Attica (10-14 years). In this school-based cross-sectional study, more than 400 variables describing anthropometric, dietary, clinical, genetic, sociodemographic and other lifestyle characteristics were collected from participating children and their families. Increased body mass index was identified in 39.3% of subjects (30.5% overweight and 8.8% obese), with males presenting a more unfavorable metabolic profile, i.e., higher blood lipids, glucose, and insulin, compared to females. Normal-weight children had a significant advantage when compared to all children of increased weight in terms of lipid profile and insulin, as well as behaviors examined. Specifically, normal-weight children exhibited less skipping of meals and less sedentary activities. The overall high prevalence of overweight and obesity in the current population is significant and underscores the need for environmental and genetic information that will shed light on the phenomenon of childhood obesity.

Mechanisms regulating the accumulation of p21(Cip1) during adipocyte hyperplasia

Knowledge concerning proliferation and differentiation of preadipocytes is essential to our understanding of adipocyte hyperplasia and its role in the etiology of childhood obesity. As a model of hyperplasia, we investigated mechanisms regulating the cyclin-dependent kinase interacting protein p21(Cip1) during clonal expansion of 3T3-L1 preadipocytes. Treating density-arrested, unstimulated cells with a specific inhibitor of the 26S proteasome resulted in accumulation of p21 protein which localized to the nucleus. These data support the hypothesis that p21 is translocated to the nucleus to be degraded in a proteasome-dependent manner maintaining low protein abundance in density-arrested cells. Stimulating these cells with a differentiation cocktail initiated a series of synchronous cell cycle events including the activation of phosphatidylinositol 3-kinase (PI3K) pathway which temporally preceded transient p21 protein accumulation. We hypothesize that p21 is phosphorylated by Akt near its NLS preventing its degradation, a notion that is supported by the observation that pharmacological inhibition of Akt suppressed p21 accumulation during mid-G1 resulting from decreased protein turnover. We also report that pharmacological inhibition of the nuclear factor kappa B (NFkB) pathway enhanced the accumulation of p21 during mid-G1 and caused cell cycle arrest in a dose dependent manner. Collectively, these data suggest that p21 protein abundance is mediated by mechanisms involving proteasome-dependent degradation by the 26S proteasome, the PI3K and the NFkB signaling pathways. Work supported by grants from American Heart Assoc (0265418U) and NIH (1R21DK072067-01).

Obesity and Health Risks

Childhood obesity is multi-factorial in etiology. Several factors contribute to the etiology of childhood obesity, and childhood obesity is itself associated with significant morbidity. This article focuses on the health risks of childhood obesity and on the prenatal and childhood influences that contribute to the genesis of childhood obesity.

Role of genetic factors in childhood obesity and in susceptibility to dietary variations

The concern about the current epidemic of obesity is heightened by recent data showing an increase in the prevalence of overweight and obesity in children and adolescents. As obese children are at increased risk of becoming obese adults, early identification of individuals at risk of becoming obese is important for the implementation of preventive measures. In that context, it is important to assess the role of genetic and nongenetic factors in childhood obesity as well as in susceptibility to dietary variations. This paper reviews recent data regarding the prevalence of obesity in childhood as well as the role of genetic factors in phenotypes related to obesity, with emphasis on studies conducted on children, when available. The existence of severe cases of obesity, such as those encountered in Mendelian syndromes of obesity or those caused by mutations in single genes, provides strong evidence for a role of genetic factors in the aetiology of childhood obesity. Furthermore, results from family studies suggest that the maximal heritability of obesity phenotypes ranges from about 30% to 50% and that the major affectors of body fat content, energy intake and energy expenditure are also influenced by genetic factors. Finally, there is increasing evidence that responsiveness to dietary intervention is genetically determined.

Development of Eating Behaviors Among Children and Adolescents

The prevalence of obesity among children is high and is increasing. We know that obesity runs in families, with children of obese parents at greater risk of developing obesity than children of thin parents. Research on genetic factors in obesity has provided us with estimates of the proportion of the variance in a population accounted for by genetic factors. However, this research does not provide information regarding individual development. To design effective preventive interventions, research is needed to delineate how genetics and environmental factors interact in the etiology of childhood obesity. Addressing this question is especially challenging because parents provide both genes and environment for children. An enormous amount of learning about food and eating occurs during the transition from the exclusive milk diet of infancy to the omnivore's diet consumed by early childhood. This early learning is constrained by children's genetic predispositions, which include the unlearned preference for sweet tastes, salty tastes, and the rejection of sour and bitter tastes. Children also are predisposed to reject new foods and to learn associations between foods' flavors and the postingestive consequences of eating. Evidence suggests that children can respond to the energy density of the diet and that although intake at individual meals is erratic, 24-hour energy intake is relatively well regulated. There are individual differences in the regulation of energy intake as early as the preschool period. These individual differences in self-regulation are associated with differences in child-feeding practices and with children's adiposity. This suggests that child-feeding practices have the potential to affect children's energy balance via altering patterns of intake. Initial evidence indicates that imposition of stringent parental controls can potentiate preferences for high-fat, energy-dense foods, limit children's acceptance of a variety of foods, and disrupt children's regulation of energy intake by altering children's responsiveness to internal cues of hunger and satiety. This can occur when well-intended but concerned parents assume that children need help in determining what, when, and how much to eat and when parents impose child-feeding practices that provide children with few opportunities for self-control. Implications of these findings for preventive interventions are discussed.

Pediatricians’ Perceptions and Practices Regarding Childhood Obesity

A 42-item Likert format questionnaire examining pediatricians' perceptions and practices concerning childhood obesity was distributed to a national random sample of 500 physicians. The overall response rate was 68%. The majority of pediatricians believed physicians are obligated to counsel parents of obese children regarding the health risks of obesity (83%), that normal weight is important to the health of children (67%), and that physicians should be role models by maintaining their normal weight (59%). However, 70% of these pediatricians believed designing programs and counseling children about weight loss was difficult, 22% felt competent in prescribing weight loss programs for children, and only 11% agreed that counseling children and parents on weight loss is professionally gratifying. At least one-half of the respondents recommended the following weight loss programs/techniques to their patients: (1) decreasing caloric consumption (84%), (2) seeing a dietitian/nutritionist (78%), (3) joining Weight Watchers (66%), (4) aerobic exercise (60%), and (5) behavior modification programs (55%). These pediatricians received most of their weight control information from medical journals (70%) and past experience (68%). We also assessed belief and attitudes concerning the effect of childhood obesity, the role obesity plays in selected diseases, and the etiology of childhood obesity.