Factors related to adiposity among children aged 3 to 7 years

Links between Childhood Obesity, High-Fat Diet, and Central Precocious Puberty

In recent years, the existing relationship between excess overweight and central precocious puberty (CPP) has been reported, especially in girls. Different nutritional choices have been associated with different patterns of puberty. In particular, the involvement of altered biochemical and neuroendocrine pathways and a proinflammatory status has been described in connection with a high-fat diet (HFD). In this narrative review, we present an overview on the relationship between obesity and precocious pubertal development, focusing on the role of HFDs as a contributor to activating the hypothalamus-pituitary-gonadal axis. Although evidence is scarce and studies limited, especially in the paediatric field, the harm of HFDs on PP is a relevant problem that cannot be ignored. Increased knowledge about HFD effects will be useful in developing strategies preventing precocious puberty in children with obesity. Promoting HFD-avoiding behavior may be useful in preserving children's physiological development and protecting reproductive health. Controlling HFDs may represent a target for policy action to improve global health.

Effects of total fat intake on bodyweight in children

BACKGROUND

As part of efforts to prevent childhood overweight and obesity, we need to understand the relationship between total fat intake and body fatness in generally healthy children.

OBJECTIVES

To assess the effects and associations of total fat intake on measures of weight and body fatness in children and young people not aiming to lose weight.

SEARCH METHODS

For this update we revised the previous search strategy and ran it over all years in the Cochrane Library, MEDLINE (Ovid), MEDLINE (PubMed), and Embase (Ovid) (current to 23 May 2017). No language and publication status limits were applied. We searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov for ongoing and unpublished studies (5 June 2017).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in children aged 24 months to 18 years, with or without risk factors for cardiovascular disease, randomised to a lower fat (30% or less of total energy (TE)) versus usual or moderate-fat diet (greater than 30%TE), without the intention to reduce weight, and assessed a measure of weight or body fatness after at least six months. We included prospective cohort studies if they related baseline total fat intake to weight or body fatness at least 12 months later.

DATA COLLECTION AND ANALYSIS

We extracted data on participants, interventions or exposures, controls and outcomes, and trial or cohort quality characteristics, as well as data on potential effect modifiers, and assessed risk of bias for all included studies. We extracted body weight and blood lipid levels outcomes at six months, six to 12 months, one to two years, two to five years and more than five years for RCTs; and for cohort studies, at baseline to one year, one to two years, two to five years, five to 10 years and more than 10 years. We planned to perform random-effects meta-analyses with relevant subgrouping, and sensitivity and funnel plot analyses where data allowed.

MAIN RESULTS

We included 24 studies comprising three parallel-group RCTs (n = 1054 randomised) and 21 prospective analytical cohort studies (about 25,059 children completed). Twenty-three studies were conducted in high-income countries. No meta-analyses were possible, since only one RCT reported the same outcome at each time point range for all outcomes, and cohort studies were too heterogeneous to combine.Effects of dietary counselling to reduce total fat intake from RCTsTwo studies recruited children aged between 4 and 11 years and a third recruited children aged 12 to 13 years. Interventions were combinations of individual and group counselling, and education sessions in clinics, schools and homes, delivered by dieticians, nutritionists, behaviourists or trained, supervised teachers. Concerns about imprecision and poor reporting limited our confidence in our findings. In addition, the inclusion of hypercholesteraemic children in two trials raised concerns about applicability.One study of dietary counselling to lower total fat intake found that the intervention may make little or no difference to weight compared with usual diet at 12 months (mean difference (MD) -0.50 kg, 95% confidence interval (CI) -1.78 to 0.78; n = 620; low-quality evidence) and at three years (MD -0.60 kg, 95% CI -2.39 to 1.19; n = 612; low-quality evidence). Education delivered as a classroom curriculum probably decreased BMI in children at 17 months (MD -1.5 kg/m2, 95% CI -2.45 to -0.55; 1 RCT; n = 191; moderate-quality evidence). The effects were smaller at longer term follow-up (five years: MD 0 kg/m2, 95% CI -0.63 to 0.63; n = 541; seven years; MD -0.10 kg/m2, 95% CI -0.75 to 0.55; n = 576; low-quality evidence).Dietary counselling probably slightly reduced total cholesterol at 12 months compared to controls (MD -0.15 mmol/L, 95% CI -0.24 to -0.06; 1 RCT; n = 618; moderate-quality evidence), but may make little or no difference over longer time periods. Dietary counselling probably slightly decreased low-density lipoprotein (LDL) cholesterol at 12 months (MD -0.12 mmol/L, 95% CI -0.20 to -0.04; 1 RCT; n = 618, moderate-quality evidence) and at five years (MD -0.09, 95% CI -0.17 to -0.01; 1 RCT; n = 623; moderate-quality evidence), compared to controls. Dietary counselling probably made little or no difference to HDL-C at 12 months (MD -0.03 mmol/L, 95% CI -0.08 to 0.02; 1 RCT; n = 618; moderate-quality evidence), and at five years (MD -0.01 mmol/L, 95% CI -0.06 to 0.04; 1 RCT; n = 522; moderate-quality evidence). Likewise, counselling probably made little or no difference to triglycerides in children at 12 months (MD -0.01 mmol/L, 95% CI -0.08 to 0.06; 1 RCT; n = 618; moderate-quality evidence). Lower versus usual or modified fat intake may make little or no difference to height at seven years (MD -0.60 cm, 95% CI -2.06 to 0.86; 1 RCT; n = 577; low-quality evidence).Associations between total fat intake, weight and body fatness from cohort studiesOver half the cohort analyses that reported on primary outcomes suggested that as total fat intake increases, body fatness measures may move in the same direction. However, heterogeneous methods and reporting across cohort studies, and predominantly very low-quality evidence, made it difficult to draw firm conclusions and true relationships may be substantially different.

AUTHORS' CONCLUSIONS

We were unable to reach firm conclusions. Limited evidence from three trials that randomised children to dietary counselling or education to lower total fat intake (30% or less TE) versus usual or modified fat intake, but with no intention to reduce weight, showed small reductions in body mass index, total- and LDL-cholesterol at some time points with lower fat intake compared to controls. There were no consistent effects on weight, high-density lipoprotein (HDL) cholesterol or height. Associations in cohort studies that related total fat intake to later measures of body fatness in children were inconsistent and the quality of this evidence was mostly very low. Most studies were conducted in high-income countries, and may not be applicable in low- and middle-income settings. High-quality, longer-term studies are needed, that include low- and middle-income settings to look at both possible benefits and harms.

Effects of total fat intake on bodyweight in children

BACKGROUND

As part of efforts to prevent childhood overweight and obesity, we need to understand the relationship between total fat intake and body fatness in generally healthy children.

OBJECTIVES

To assess the effects of total fat intake on measures of weight and body fatness in children and young people not aiming to lose weight.

SEARCH METHODS

For this update we revised the previous search strategy and ran it over all years in the Cochrane Library, MEDLINE (Ovid), MEDLINE (PubMed), and Embase (Ovid) (current to 23 May 2017). No language and publication status limits were applied. We searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov for ongoing and unpublished studies (5 June 2017).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in children aged 24 months to 18 years, with or without risk factors for cardiovascular disease, randomised to a lower fat (30% or less of total energy (TE)) versus usual or moderate-fat diet (greater than 30%TE), without the intention to reduce weight, and assessed a measure of weight or body fatness after at least six months. We included prospective analytical cohort studies in these children if they related baseline total fat intake to weight or body fatness at least 12 months later. We duplicated inclusion decisions and resolved disagreement by discussion with other authors.

DATA COLLECTION AND ANALYSIS

We extracted data on participants, interventions or exposures, controls and outcomes, and trial or cohort quality characteristics, as well as data on potential effect modifiers, and assessed risk of bias for all included studies. We extracted outcome data using the following time point ranges, when available: RCTs: baseline to six months, six to 12 months, one to two years, two to five years and more than five years; cohort studies: baseline to one year, one to two years, two to five years, five to 10 years and more than 10 years. We planned to perform random-effects meta-analyses with relevant subgrouping, and sensitivity and funnel plot analyses where data allowed.

MAIN RESULTS

We included 24 studies comprising three parallel-group RCTs (n = 1054 randomised) and 21 prospective analytical cohort studies (about 25,059 children completed). Twenty-three were conducted in high-income countries. No meta-analyses were possible, since only one RCT reported the same outcome at each time point range for all outcomes, and cohort studies were too heterogeneous.For the RCTs, concerns about imprecision and poor reporting limited our confidence in our findings. In addition, the inclusion of hypercholesteraemic children in two trials raised concerns about applicability. Lower versus usual or modified total fat intake may have made little or no difference to weight over a six- to twelve month period (mean difference (MD) -0.50 kg, 95% confidence interval (CI) -1.78 to 0.78; 1 RCT; n = 620; low-quality evidence), nor a two- to five-year period (MD -0.60 kg, 95% CI -2.39 to 1.19; 1 RCT; n = 612; low-quality evidence). Compared to controls, lower total fat intake (30% or less TE) probably decreased BMI in children over a one- to two-year period (MD -1.5 kg/m2, 95% CI -2.45 to -0.55; 1 RCT; n = 191; moderate-quality evidence), with no other differences evident across the other time points (two to five years: MD 0.00 kg/m2, 95% CI -0.63 to 0.63; 1 RCT; n = 541; greater than five years; MD -0.10 kg/m2, 95% CI -0.75 to 0.55; 1 RCT; n = 576; low-quality evidence). Lower fat intake probably slightly reduced total cholesterol over six to 12 months compared to controls (MD -0.15 mmol/L, 95% CI -0.24 to -0.06; 1 RCT; n = 618; moderate-quality evidence), but may make little or no difference over longer time periods. Lower fat intake probably slightly decreased low-density lipoprotein (LDL) cholesterol over six to 12 months (MD -0.12 mmol/L, 95% CI -0.20 to -0.04; 1 RCT; n = 618, moderate-quality evidence) and over two to five years (MD -0.09, 95% CI -0.17 to -0.01; 1 RCT; n = 623; moderate-quality evidence), compared to controls. However, lower total fat intake probably made little or no difference to HDL-C over a six- to 12-month period (MD -0.03 mmol/L, 95% CI -0.08 to 0.02; 1 RCT; n = 618; moderate-quality evidence), nor a two- to five-year period (MD -0.01 mmol/L, 95% CI -0.06 to 0.04; 1 RCT; n = 522; moderate-quality evidence). Likewise, lower total fat intake probably made little or no difference to triglycerides in children over a six- to 12-month period (MD -0.01 mmol/L, 95% CI -0.08 to 0.06; 1 RCT; n = 618; moderate-quality evidence). Lower versus usual or modified fat intake may make little or no difference to height over more than five years (MD -0.60 cm, 95% CI -2.06 to 0.86; 1 RCT; n = 577; low-quality evidence).Over half the cohort analyses that reported on primary outcomes suggested that as total fat intake increases, body fatness measures may move in the same direction. However, heterogeneous methods and reporting across cohort studies, and predominantly very low-quality evidence, made it difficult to draw firm conclusions and true relationships may be substantially different.

AUTHORS' CONCLUSIONS

We were unable to reach firm conclusions. Limited evidence from three trials that randomised children to a lower total fat intake (30% or less TE) versus usual or modified fat intake, but with no intention to reduce weight, showed small reductions in body mass index, total- and LDL-cholesterol at some time points with lower fat intake compared to controls, and no consistent differences in effects on weight, high-density lipoprotein (HDL) cholesterol or height. Associations in cohort studies that related total fat intake to later measures of body fatness in children were inconsistent and the quality of this evidence was mostly very low. Twenty-three out of 24 included studies were conducted in high-income countries, and may not be applicable in low- and middle-income settings. High-quality, longer-term studies are needed, that include low- and middle-income settings and look at both possible benefits and risks.

Organized sport and physical activity participation and body mass index in children and youth: A longitudinal study

The relationship between sport participation and BMI in children and adolescents is unclear, with some studies showing no association at all and others suggesting that sport is linked to lower BMI. Another possibility, however, is that this relationship is bidirectional, with sport leading to lower BMI but BMI also influencing sport participation. Here, we examine the direction of this association by analyzing a longitudinal dataset. Data come from the Physical Health Activity Study Team (PHAST) study, a prospective open cohort study including 2278 children at baseline, followed from 2004 to 2010. We fit 3 lagged mixed effects models: One examining the simultaneous relationship, one regressing past BMI on present sport participation, and one regressing sport participation on present BMI. Our baseline sample included 1999 children, of whom 50% were female. Mean BMI increased over the study period from 19.0 (SD = 3.7) to 21.2 (SD = 4.1), while organized sport participation declined. Model results showed that BMI and sport are weakly associated, and that each of these variables predicts the other, which generally supports a bidirectional relationship. Consistent with some previous reports, however, the effect size in both directions is very small. At the levels of participation in our sample, activity and BMI are very weakly related. Findings should not obscure the other benefits of physical activity.

'Croque&bouge': A feasible and acceptable programme for obesity prevention in preschoolers at risk and their parents

OBJECTIVES

To conceptualize and pilot test a programme of three workshops aiming to prevent the development of overweight in susceptible preschool children.

METHODS

Three workshops were conducted, targeting both parents and children. The curriculum for parents included discussions on feeding responsibilities, healthy eating, taste development, neophobia and physical activity recommendations. Children participated in various play activities with fruits and vegetables and read stories about hunger and satiety feelings. Recruitment was organized through paediatricians and child-care centres. Evaluation of the programme focused on feasibility, adequacy for children's age, parents' perception of impact and, for children, change of the ability to recognize and willingness to taste fruits and vegetables.

RESULTS

A total of 21 children and one of their parents participated in the programme. The programme was found to be feasible and adequate for the targeted community. Parents reported perceiving a positive impact of the intervention; however, this finding was not statistically significant. The major difficulty was identifying and recruiting families and engaging the parents in a discussion about weight.

CONCLUSIONS

This short programme aiming to improve parents' ability to offer healthy environment and promote healthy eating behaviour was feasible and acceptable for families with young children. When developing and implementing such programmes, close collaboration with paediatricians and other health providers should be sought in order to identify and reach children at risk of obesity and their family.

Accuracy of parental report and electronic health record documentation as measures of diet and physical activity counseling

OBJECTIVE

To determine whether parental reports and electronic health record documentation of physician counseling on nutrition and physical activity reflect actual counseling provided.

METHODS

Participants were parents of 198 children 2 to 12 years of age seen in a primary care pediatric clinic at an academic medical center for well child care and their 38 physicians. Parents completed a post-visit questionnaire to report discussions on weight, nutrition, and physical activity that occurred during the visit. Electronic health records were reviewed to measure documentation of these topics during the visit. Parental reports and records were compared with actual discussions on the basis of coded audiotapes. Counseling was coded as having occurred if specific topics were mentioned during the encounter, however brief this mention was.

RESULTS

A total of 48% of the children were female, they were a mean age of 5.4 years, and 28% were overweight or obese. Sensitivity of parental report was high (63%-96%), but specificity was low (43%-77%) because of parents' tendency to overreport counseling. Sensitivity of electronic health record documentation was generally low (40%-53%) except for discussion of screen time (92%) and physical activity (88%); the specificity of these data was also poor (42% and 21%, respectively, for screen time and physical activity).

CONCLUSIONS

Electronic health record documentation may not be the most valid method of measuring physician counseling on weight, nutrition, and physical activity in pediatric primary care. Parental report via the use of a questionnaire administered immediately after the visit is a better alternative in quality improvement or research studies when resources do not allow for direct observation, with the caveat that parents may overreport whether counseling was provided.

Is directly measured physical activity related to adiposity in preschool children?

This review summarizes the association between directly assessed physical activity and adiposity in preschool children (age 1.5-6 years). It includes 17 cross-sectional and longitudinal studies that were published between January 1999 and February 2010. The association between physical activity and obesity seems to depend on the outcome measure of adiposity. In 60% (3/5) of the studies using percentage body fat, an inverse significant relationship with physical activity was found against 18% (2/11) of the studies that used body mass index as method to assess adiposity. Physical activity is inversely related to percentage body fat in preschool children. The associations between physical activity and body mass index as a measure of adiposity in preschool children remain elusive. Further studies using directly measured physical activity and percentage body fat to define adiposity are needed to draw more firm conclusions.

Evaluation of the health status of preschool children stratified based on the weight-length index (WLI)

This study was conducted to prepare basic materials and offer advice regarding dietary habits to prevent and cure childhood obesity by comparing and analyzing dietary habit, nutritional status, blood factors, and mineral contents of hair. All subjects were stratified by their weight-length index (WLI). According to the standard WLI values, 64.9% of children were within the normal value, 13.5% of children were underweight, and 21.6% of children were overweight and obese (WLI ≥ 110%). Overall, the score assessed dietary habit for all children was 21.32 ± 2.55 point (921 subjects), with 5.1% of children having excellent dietary habits and 3.1% having poor dietary habits. Additionally, 37.9% of underweight children, 37.6% of normal weight children, and 43.2% of overweight and obese children consumed higher amounts of protein than underweight children did (meat, fish, eggs, and soy products) (P < 0.05). Overweight and obese children consumed more fried foods than underweight or normal weight children (P < 0.05). Moreover, 38.0% of the children had hemoglobin levels of 12 g/dl, while 7.6% were anemic (11.1 g/dl). When a hematocrit level of 33% was taken as the standard, 11.0% of children were anemic. The plasma transferrin content was 263.76 ± 54.52 mg/dl in overweight and obese children. The mean values of Fe, Cu, Ca, Cr, Mn, Se, Na, K, Li, V, Co, and Mo were within the reference values, but the Zn concentrations of underweight, normal weight, and overweight and obese children were 67.97 ± 28.51 ppm, 70.09 ± 30.81 ppm, and 73.99 ± 30.36 ppm, respectively. The Zn concentration of overweight and obese children (73.99 ± 30.36 ppm) was lower than that of the standard value (180~220 ppm). Therefore, a nutritional education program and new guidance for dietary pattern should be developed to reduce the number of underweight and overweight and obese children.

Relationship of food frequencies as reported by parents to overweight and obesity at 5 years

AIM

To investigate if food frequencies are related to overweight/obesity in 5-year-old children.

METHODS

During 1997-1999, 21 700 infants were invited to participate in ABIS (All Babies in Southeast Sweden), a prospective, cohort study. Participants were followed from birth (n = 16 058) to 5 years (n = 7356). Food frequencies reported by parents at 2.5 and 5 years were studied in the relation to overweight/obesity at 5 years using multiple logistic regressions. A p-value < 0.01 was considered statistically significant.

RESULTS

At 2.5 years frequencies of intake of cheese were positively associated with overweight/obesity at 5 years while porridge, fried potatoes/french fries and cream/crème fraiche showed a negative association. When adjusting for known risk factors, porridge and fried potatoes/french fries remained negatively associated with overweight/obesity. At 5 years, chocolate and lemonade were positively associated with overweight/obesity whereas cream/crème fraiche, pastries and candy were negatively associated. Candy remained negatively associated to overweight/obesity after adjustment for potential confounders.

CONCLUSION

Food frequencies do not offer any simple explanation for overweight/obesity. Porridge at 2.5 years may protect against overweight/obesity at 5 years, while lemonade may contribute to overweight. Our finding that fried potatoes/french fries may protect against overweight/obesity is unexpected and must be interpreted with caution. These findings should be confirmed by prospective studies using objective recordings.

A cross-cultural comparison of dietary intakes and physical activity between American and Czech school-aged children

OBJECTIVE

The prevalence of child overweight in the Czech Republic is substantially lower than that in the USA. The objective of the present pilot study was to explore dietary intakes, frequency of dining in fast-food establishments, and the amount and intensity of physical activity between a sample of American and Czech children.

DESIGN

A cross-sectional correlational pilot study.

SETTING

Four public schools in the USA and four public schools in the Czech Republic.

SUBJECTS

Ninety-five Czech and forty-four American 4-6th graders from urban public schools participated in the study. Dietary intake and number of fast-food visits were evaluated using two multiple-pass 24 h recalls. Physical activity was measured using the modified Self-Administered Physical Activity Checklist.

RESULTS

American children (mean age 10.8 (SE 0.2) years) consumed more energy and fat, less fruits and vegetables, more soft drinks, and visited fast-food establishments more often than Czech children (mean age 11.0 (SE 0.1) years). Although no differences were found in vigorous activity by nationality, Czech children spent significantly more time in moderate physical activities than American children.

CONCLUSIONS

Despite the influx of some negative Western dietary trends into the country, Czech children had a healthier diet and were more physically active than American children. Further research is warranted to determine whether the same differences in dietary intakes, physical activity and fast-food visits exist between nationally representative samples of American and Czech children.

Recommendations for prevention of childhood obesity

The majority of US youth are of healthy weight, but the majority of US adults are overweight or obese. Therefore, a major health challenge for most American children and adolescents is obesity prevention-today, and as they age into adulthood. In this report, we review the most recent evidence regarding many behavioral and practice interventions related to childhood obesity, and we present recommendations to health care providers. Because of the importance, we also suggest approaches that clinicians can use to encourage obesity prevention among children, including specific counseling strategies and practice-based, systems-level interventions. In addition, we suggest how clinicians may interact with and promote local and state policy initiatives designed to prevent obesity in their communities.

Food category purchases vary by household education and race/ethnicity: results from grocery receipts

OBJECTIVE

To characterize food group purchases from grocery receipts.

METHODS

Food shoppers (aged>or=19 years with at least one child aged<or=18 years in the home, the family's primary food purchaser) were recruited in front of grocery stores to participate in two interviews, separated by 6 weeks, and to save and mail grocery store receipts from the interim to researchers. Receipt items were coded by food categories; the percentage of total grocery dollars spent in each of the food categories each week was computed. Analyses of variance were performed on the total grocery dollar spent and the percentage spent in each food category by participant characteristics.

RESULTS

The greatest percentage of purchases were for protein foods (24%), followed by drinks (12%), grains (9.2%), vegetables (8.8%), dairy (8.3%), mixed dishes (7.5%), and fruit (7%). Hispanics purchased a greater percentage of fruit and vegetables than African Americans. Whites purchased more alcohol products than African Americans. Whites purchased more mixed dishes than Hispanics, and African Americans purchased more protein foods than whites (all P<0.001).

CONCLUSIONS

The use of this measurement procedure, unaffected by errors of self-report, should be more thoroughly explored to explain differences in disease prevalence.

Low-income, overweight and obese mothers as agents of change to improve food choices, fat habits, and physical activity in their 1-to-3-year-old children

OBJECTIVE

To examine the effects of a weight loss program for mothers on the diet and activity of mothers and their 1-3 year old children.

DESIGN

Overweight and obese mothers participated in an 8-week weight loss intervention encompassing diet, physical activity, and behavioral modification. Anthropometrics, demographic, dietary, and physical activity questionnaires were administered at weeks 0 and 8; anthropometrics were re-evaluated at week 24.

SUBJECTS

Mothers (N=91) of a 1-3 year old child; body mass index (BMI) >or= 25 kg/m2; non-breastfeeding; age 18-45 years; income < 200% of federal poverty index; Hispanic, African American, or white; and English-speaking were recruited from Special Supplemental Program for Women Infants and Children (WIC) and public health clinics. INTERVENTION MEASURES OF OUTCOME: Weight loss in mothers and improvements in diet (reduction in calories, fat, snacks/desserts, sweetened beverages, and increases in fruit, vegetables) and activity in mothers and children.

RESULTS

Weight loss in mothers was modest (-2.7 kg, p < 0.001) and sustained at week 24 (-2.8 kg, p < 0.001), and children gained in height and weight as expected for normal growth (p < 0.001). Initial energy intakes of children exceeded Estimated Energy Requirements (123%) and were reduced to acceptable levels post-intervention (102%, p < 0.001); additional beneficial changes in children's diets were decreased total (47.7 to 39.9 g/day) and saturated fat (19.2 to 16.6 g/day), high-fat snacks/desserts (1.6 to 0.9 servings/day), added fats (81.8 to 40.9% using), sweetened beverages (0.8 to 0.4 servings/day), and fast food consumption (11.6 to 6.6% of meals), and increased home-prepared meals (63.2 to 71.6% of meals) (p < 0.01 for all). Physical activity scores improved by 7% in children (p < 0.05). Comparable changes in food choices and activity also were seen in mothers.

CONCLUSION

Offering weight loss classes was a successful method of enticing low-income women to participate in an educational intervention that benefited their children. Overweight and obese mothers who modified their food choices and fat habits made comparable changes for their child.

The aetiology of childhood obesity: a review

Whilst the prevention of childhood obesity is the only viable, enduring, cost-effective solution to the obesity epidemic, effective methods for it remain elusive. Furthermore, strategies to influence obesogenic environments remain relatively unexplored. In order to be able to develop powerful population-level interventions and public health policies to prevent childhood obesity, it is important to understand its aetiology and those environments that are most amenable to measurable change. First, the present paper considers why we should be concerned about obesity in children, from both the perspective of the increased health risk to the individual and the high economic cost of treatment of obesity and related diseases, highlighting why the prevention of childhood obesity is important. Next, the determinants of health behaviour and the obesogenic environment are explored, which helps us to understand why the aetiology is so complex and that potential causal factors should not be considered in isolation, as the interaction between these factors is also important. The paper then considers the multi-factorial aetiology of childhood obesity and the rationale for the increasing trends in obesity that are evident, in order to understand what is changing in society and our children's behaviour that is triggering the positive energy balance leading to obesity. The review emphasises the need for multi-level approaches if we truly want to prevent childhood obesity. It also serves to highlight that there is a need to extend the current research base in order to build a well-founded framework to form the basis of a strategy for the prevention of childhood obesity.

Factors associated with adolescents' overweight and obesity at community, school and household levels in Xi'an City, China: results of hierarchical analysis

OBJECTIVE

To identify personal and environmental factors associated with adolescent overweight and obesity in Xi'an city, China.

SUBJECTS/METHODS

A total of 1804 adolescents from 30 junior high schools in six districts in Xi'an City. Community, school, household and individual characteristics were self reported by parents, school doctors and students. Factors associated with adolescent overweight and obesity were identified using a hierarchical logistic regression.

RESULTS

In all adolescents, after adjustment for age and gender, factors significantly associated with overweight and obesity were: living in urban districts (odds ratio (OR): 4.0, 95% confidence interval (CI): 2.7-6.0); limited use of school sports facilities (OR: 1.7, 95% CI: 1.1-2.6); wealthy households (OR: 1.7, 95% CI: 1.1-2.6); parental restrictions on purchasing snacks (OR: 1.5, 95% CI: 1.03-2.0); having an overweight/obese parent (OR: 1.8, 95% CI: 1.3-2.5); having soft drinks more than four times per week (OR: 1.6, 95% CI: 1.02-2.5) and not fussy about foods (OR: 1.7, 95% CI: 1.2-2.2). Eating sweets was negatively associated with overweight/obesity (OR: 0.6, 95% CI: 0.4-0.9). Separate gender analyses revealed that in boys, low physical activity (OR: 2.0, 95% CI: 1.1-3.8) and higher energy intake (OR: 1.8, 95% CI: 1.1-2.9) were also associated with overweight/obesity. In girls, less school sports meetings (OR: 2.3, 95% CI: 1.3-4.0); parental decisions about eating fast foods (OR: 1.8, 95% CI: 1.1-2.9) and availability of home video games (OR: 1.7, 95% CI: 1.1-2.5) were also significant.

CONCLUSIONS

Preventive strategies for adolescent overweight and obesity in Xi'an should address the community and school environments to reinforce behavioral change. Gender differences also need to be considered when planning interventions.

Are dietary intakes and eating behaviors related to childhood obesity? A comprehensive review of the evidence

The purpose of this article is to comprehensively review studies that have examined the relation between diet and childhood obesity. The review specifically considers the roles of total energy intake and energy density; dietary composition; individual foods, food groups, and dietary patterns; beverage consumption; and eating behaviors. The paper also discusses methodological considerations and future research directions and concludes by summarizing the evidence presented and highlighting the ethical issues surrounding providing dietary advice.

An assessment of obese and non obese girls' metabolic rate during television viewing, reading, and resting

While childhood obesity has been linked to television (TV) viewing, specific mechanisms are not well understood. Obesity related to TV viewing might plausibly be related to decreased physical activity, increased food intake, reductions in metabolic rate, or combinations of these. The current investigation sought to ascertain the metabolic effects of quiet rest, listening to a story, watching a passive TV program, and watching an active TV show. Counter-balanced conditions were presented to 90 pre-pubertal girls ranging in body mass index from underweight to obese. In addition, effects between resting energy expenditure (REE) and race, body mass index, skinfold measures, physical activity, pubertal stage and average hours spent viewing TV were explored. Results indicated no significant differences in metabolic rate between weight groups nor between activity conditions (story listening and TV viewing) and rest conditions. A significant dose-response relationship was found in which REE decreased as average weekly hours of TV viewing increased, after adjusting for body mass index and puberty stage. Additionally, later stages of pubertal development compared to earlier stages were related to higher levels of REE. Results of this study suggest that metabolic rate alone cannot account for the consistently observed relationship between television viewing and obesity. Future studies should focus on energy intake, physical inactivity, or combinations of these with metabolic rate in seeking specific mechanisms responsible for television viewing related to obesity.

Short-term predictors of abdominal obesity in children

BACKGROUND

The aim of this study was to examine the short-term tracking of abdominal adiposity in children.

METHODS

A total of 918 children (477 boys) aged 6-12 years at baseline were followed-up for 2 years. Central obesity was assessed by waist circumference (WaistC), whereas body fat distribution by waist-to-hip ratio. Maturity was assessed by the Khamis-Roche method. Parental fatness and children's cardiorespiratory fitness (CRF) were also evaluated. Multiple and logistic regressions were employed to identify the predictors of BMI and WaistC.

RESULTS

Tracking of body fatness and body fat distribution was high (r = 0.69-0.86, P < 0.01). More boys remained obese than girls (P < 0.05), whereas a greater percentage of boys moved to a higher quartile of WaistC after the 2-year follow-up (22.0 vs 14.1%, P < 0.01). Sex, child's maturity and WaistC at baseline, CRF, and maternal BMI explained 76% of the variability in BMI and WaistC at the follow-up (n = 290). Children with high WaistC at baseline and low CRF presented 1.9- and 4.3-fold increased risk of remaining in the upper quartile of WaistC at the follow-up (P < 0.01; n = 552).

CONCLUSION

Youth with increased WaistC at baseline and low CRF presented an increased chance of maintaining central obesity at the follow-up. More boys than girls moved into a higher quartile of abdominal obesity during the 2-year follow-up period and this should be taken into account in designing programmes for childhood obesity.

Anthropometric, parental, and psychosocial correlates of dietary intake of African-American girls

OBJECTIVE

This paper identifies the anthropometric, parental, and psychosocial characteristics and meal practices (e.g., breakfast skipping and number of meals and snacks consumed) associated with consumption of total energy, percent energy from fat, fruit, 100% fruit juice, vegetables, sweetened beverages, and water among 8- to 10-year-old African-American girls.

RESEARCH METHODS AND PROCEDURES

This study included 114 8- to 10-year-old African-American girls and a parent or primary caregiver. Girls and a parent or primary caregiver completed several dietary questionnaires. Two 24-hour dietary recalls were conducted with each girl. Height and weight were measured. Separate hierarchical regression analyses were conducted for each dependent dietary variable; potential field center differences were examined.

RESULTS

The number of meals and snacks consumed was correlated with energy intake. Lower BMI was related to higher vegetable consumption, and the number of snacks consumed was positively related to sweetened beverage consumption. Greater low-fat food preparation practices reported by parents were related to lower consumption of fat as a percentage of total energy.

DISCUSSION

Dietary behavior differed across geographic areas. Low-fat food preparation practices in the home seemed to be an important influence on the percentage of energy consumed from fat. Greater vegetable consumption was associated with lower BMI. Interventions to prevent excessive weight gain in African-American girls should encourage low-fat food preparation in the home and greater consumption of vegetables.

Pattern of long-term fat intake and BMI during childhood and adolescence—results of the DONALD Study

OBJECTIVE

Adverse dietary habits have been discussed as being conducive to the increased prevalence of obesity in children and adolescents. No single dietary factor has been clearly identified so far. We analyzed long-term fat intake patterns during childhood and adolescence and their influence on body fatness.

METHODS

Four clusters with different patterns of percent energy from fat were found in 228 individuals from the age of 2-18 y participating in the DONALD Study (Dortmund Nutritional Anthropometric Longitudinally Designed Study) with at least 10 yearly weighed dietary records between 1985 and 2002. Clusters were evaluated with regard to macronutrient and food group intakes and body mass index (BMI).

RESULTS

The mean energy density and the ratio of energy intake to estimated basal metabolic rate per subject differed significantly between clusters. All calculated macronutrients (per energy intake) with the exception of dietary fiber differed significantly as well as intakes of Meat/Fish/Eggs, Fats/Oils and Fruit/Vegetables. Although these differences in dietary characteristics persisted during the study period, no differences of BMI (calculated as standard deviation score) were found either at the first or last examination per subject. The mean BMI during the study period differed significantly, with the highest BMI in the low fat intake cluster.

CONCLUSION

BMI could not be explained by different dietary patterns during childhood and adolescence in this long-term evaluation of dietary records. Underreporting especially in obese subjects, the problem of detecting minor overconsumption of energy intake that favors the development of obesity over long periods, and the small study sample may explain these conflicting results.

Relationship of child-feeding practices to overweight in low-income Mexican-American preschool-aged children

OBJECTIVE

The purpose of this research was to examine the relationship of child-feeding practices and other factors to overweight in low-income Mexican-American preschool-aged children.

DESIGN

Cross-sectional survey with anthropometric measurements of mothers and target children. Trained bilingual staff interviewed the parents to collect data on child-feeding strategies, food patterns, child's health history, parental acculturation level, food insecurity, and other household characteristics. Subjects and setting Complete data were available from 204 low-income Mexican-American parents residing in California with at least one child aged 3 to 5 years. Outcomes measured Risk of overweight was defined as body mass index (BMI) (measured as weight [in kilograms]/height [in meters](2)) >/=85th percentile and overweight was defined as BMI >/=95th percentile. The Student t test, chi(2) test, and logistic regression were used.

RESULTS

Three variables were positively related to risk of overweight: birth weight (odds ratio [OR], 2.31; 95% confidence interval [CI], 1.11 to 4.82), mother's BMI >/=30 (OR, 2.05; 95% CI, 1.11 to 3.79), and juice intake (OR, 2.33; 95% CI, 1.09 to 4.98). Being enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children was negatively related to risk of overweight (OR, 0.40; 95% CI, 0.21 to 0.75). Additional variables related to overweight were monthly income >$1,500 (OR, 2.33; 95% CI, 1.00 to 5.42) and child takes food from the refrigerator between meals (OR, 0.32; 95% CI, 0.13 to 0.76).

CONCLUSIONS

The results of this study suggest that biological and socioeconomic factors are more associated with overweight in Mexican-American preschool-aged children than most of the self-reported child-feeding strategies.

Parents are key players in the prevention and treatment of weight-related problems

There is growing agreement among experts that an obesogenic environment, which encourage excess food intake and idealizes thinness, plays a crucial role in the epidemic of childhood obesity and eating disorders. Because parents provide a child's contextual environment, they should be considered key players in interventions aimed at preventing or treating weight-related problems. Parenting style and feeding style are crucial factors in fostering healthy lifestyle and awareness of internal hunger and satiety cues and de-emphasizing thinness. Effective interventions for prevention and treatment of weight-related problems should be approached from a health-centered rather than a weight-centered perspective, with the parents as central agents of change. This paper reviews the environmental risk factors and parents' role in the prevention and treatment of children's weight-related problems.

Are current health behavioral change models helpful in guiding prevention of weight gain efforts?

Effective procedures are needed to prevent the substantial increases in adiposity that have been occurring among children and adults. Behavioral change may occur as a result of changes in variables that mediate interventions. These mediating variables have typically come from the theories or models used to understand behavior. Seven categories of theories and models are reviewed to define the concepts and to identify the motivational mechanism(s), the resources that a person needs for change, the processes by which behavioral change is likely to occur, and the procedures necessary to promote change. Although each model has something to offer obesity prevention, the early promise can be achieved only with substantial additional research in which these models are applied to diet and physical activity in regard to obesity. The most promising avenues for such research seem to be using the latest variants of the Theory of Planned Behavior and Social Ecology. Synergy may be achieved by taking the most promising concepts from each model and integrating them for use with specific populations. Biology-based steps in an eating or physical activity event are identified, and research issues are suggested to integrate behavioral and biological approaches to understanding eating and physical activity behaviors. Social marketing procedures have much to offer in terms of organizing and strategizing behavioral change programs to incorporate these theoretical ideas. More research is needed to assess the true potential for these models to contribute to our understanding of obesity-related diet and physical activity practices, and in turn, to obesity prevention.

Does early physical activity predict body fat change throughout childhood?

BACKGROUND

Declining levels of physical activity in the population at large may be responsible in part for the rising rates of childhood obesity. Studies to date, however, have not consistently demonstrated such a protective effect. We used longitudinal data from the Framingham Children's Study (FCS) to address this important question.

METHODS

We used 8 years of activity monitoring (Caltrac electronic motion sensors) and repeated anthropometry measures for 103 children to examine the effect of activity on body fat change from preschool to early adolescence. Longitudinal data analysis methods were employed to account for the use of repeated measures on these children.

RESULTS

Children in the highest tertile of average daily activity from ages 4 to 11 years had consistently smaller gains in BMI, triceps, and sum of five skinfolds throughout childhood. By early adolescence (age 11), the sum of five skinfolds was 95.1, 94.5, and 74.1 for the low, middle, and high tertiles of activity, respectively (P for trend = 0.045). This protective effect of activity was evident for both girls and boys.

CONCLUSION

This longitudinal study adds strong support for the hypothesis that higher levels of physical activity during childhood lead to the acquisition of less body fat by the time of early adolescence.

Influences on diet and physical activity among middle-class African American 8- to 10-year-old girls at risk of becoming obese

OBJECTIVE

To understand diet, physical activity, and inactivity influences among preadolescent African American girls at risk of becoming obese.

DESIGN

Interviews and group qualitative discussions (i.e., mixed qualitative research method) were conducted separately with 8- to 10-year-old African American girls and their parents.

SETTING

Greater Houston, Texas.

PARTICIPANTS

Eight- to 10-year-old African American girls above the 50th percentile body mass index with a home computer (n = 82) and a parent (n = 74).

VARIABLES MEASURED

Influences on dietary practices and physical activity/inactivity among preadolescent African American girls.

ANALYSIS

Discussions were audiotaped, manually recorded, transcribed, and coded. The primary coder analyzed the transcribed notes. The secondary coder reviewed and critiqued the initial coding.

RESULTS

Parents and girls were concerned about overweight and viewed physical activity as a weight control practice. Mothers facilitated daughters' physical activity, while fathers and siblings were coparticipants. Girls had access to physical activity equipment and facilities. Snack food items and carbonated beverages were often limited by the parents, and water consumption was encouraged. Discrepancies were apparent between girls' and parents' responses.

CONCLUSIONS AND IMPLICATIONS

Parental convenience and girls' food preferences influenced dietary intake. Obesity prevention programs should capitalize on parental motivation for their child's health and provide practical strategies to facilitate healthful eating and physical activity.

Hip-Hop to Health Jr., an obesity prevention program for minority preschool children: baseline characteristics of participants

BACKGROUND

The prevalence of obesity in the United States is a significant public health problem. Many obesity-related risk factors are more prevalent in minority populations. Given the recalcitrant nature of weight loss interventions for adults, prevention of overweight and obesity has become a high priority. The present study reports baseline data from an obesity prevention intervention developed for minority preschool children.

METHODS

Hip-Hop to Health Jr. is a 5-year randomized controlled intervention that targets 3- to 5-year-old minority children enrolled in 24 Head Start programs. Our primary aim is to test the effect of the intervention on change in body mass index. Data were collected on sociodemographic, anthropometric, behavioral, and cognitive variables for the children and parents at baseline.

RESULTS

Participants included 416 black children, 337 black parents, 362 Latino children, and 309 Latino parents. Using body mass index for age and sex > or = the 95th percentile as the definition of overweight, 15% of the black children and 28% of the Latino children were overweight. More than 75% of the parents were either overweight or obese.

DISCUSSION

The development of interventions to effectively prevent or control obesity early in life is crucial. These data highlight the escalating problem of weight control in minority populations.

Children's dietary fat intake and fat practices vary by meal and day

OBJECTIVE

This research examined the relationship between the dietary fat intake and fat practices of children by meal, day of week, and weekend day vs weekday.

DESIGN

Cross-sectional study.

SUBJECTS/SETTING

Fourth- to sixth-grade students (n = 520; 25% African-American, 32% white, 33% Mexican-American, 10% Asian/other, 58% girls) attending 8 parochial schools in Houston, Texas.

MAIN MEASURES

Students completed daily food records in the classroom for 7 days. Food records were hand-coded for high-fat (eg, frying foods, adding fat) and low-fat (eg, removing meat fat, drinking low-fat milk) practices, and percent energy from fat.

STATISTICAL ANALYSES

Descriptive statistics, Spearman correlation coefficients, and analysis of variance on fat intake and fat practices by demographic variables and weekend vs weekday.

RESULTS

Students consumed 36% of total energy from fat, reported 0.59 low-fat practices, and 6.3 high-fat practices per day. Only 13% consumed 30% or less energy from fat. Significant correlations were found between percent energy from fat and high-fat practices and low-fat practices (r = 0.27, P < .001 and r = -0.15, P < .01, respectively).

APPLICATIONS/CONCLUSIONS

Intervention programs targeting children's dietary fat behaviors should include teaching skills that enable children to ask for low-fat foods like fruit, vegetables, low-fat snacks and dairy foods. These foods should be made available in the home to encourage children to practice low-fat dietary behaviors, which may differ depending on meal, day, and meal source.

Familial concordance of dietary fat practices and intake

This study examined parent and child dietary fat practices and child dietary fat intake. High- and low-fat practices and percentage of kilocalories from fat were obtained from food records completed by 132 students in the 4th to 6th grades. Parents completed three scales: meat modifications (MMOD); fat substitutions (FSUB); and fruit, juice, and vegetable practices (FJVP). A parent low-fat practices (PLFP) scale was created with the items matching the child low-fat practices (LFPs). Parent PLFP, FSUB, and FJVP were significantly correlated with child LFPs. Parent LFP was a significant predictor of child LFP. Family intervention programs targeting dietary fat behaviors should encourage use of low-fat dietary behaviors.

Child and parent characteristics as predictors of change in girls' body mass index

OBJECTIVE

This study assessed predictors of change in girls' body mass index (BMI) between ages 5 and 7 y and familial aggregation of risk factors associated with childhood overweight.

METHOD

Participants included 197 5-y-old girls and their parents, of whom 192 were reassessed when girls were 7-y-old. Three classes of predictors of girls' change in BMI were assessed including girls' and parents' weight status, dietary intake and physical activity. Girls' and parents' BMI and change in BMI were calculated based on height and weight measurements. Girls' dietary intake was assessed using three 24 h recalls; parents' intake was assessed using a food frequency questionnaire. Girls and mothers provided reports of girls' physical activity; parents' frequency and enjoyment of activity were assessed using a self-administered questionnaire.

RESULTS

The most effective model predicting girls' change in BMI between ages 5 and 7 included both child and parent characteristics, specifically girls' BMI at age 5, mothers' change in BMI, fathers' energy intake, fathers' enjoyment of activity, and girls' percentage of energy from fat. In addition, results showed substantial intra-familial associations in weight status and dietary intake and to a lesser extent physical activity, and the presence of multiple risk factors within families. Associations were also noted between girls' and parents' change in BMI.

CONCLUSIONS

Results from this study highlight the centrality of the family in the etiology of childhood overweight and the necessity of incorporating parents in the treatment of childhood overweight.

Childhood overweight: a contextual model and recommendations for future research

The prevalence of overweight among children has doubled within the past two decades. Increases in the rate of childhood overweight are of particular concern due to the negative health and psychological effects noted among overweight children. As shown by previous research, the development of childhood overweight involves a complex set of factors from multiple contexts that interact with each other to place a child at risk of overweight. This multifaceted system can be conceptualized using Ecological Systems Theory (EST). EST highlights the importance of considering the context(s), or ecological niche, in which a person is located in order to understand the emergence of a particular characteristic. In the case of a child, the ecological niche includes the family and the school, which are in turn embedded in larger social contexts including the community and society at large. In this review, EST is used as a framework with which to summarize research assessing predictors of childhood overweight. Specifically, child characteristics that place children at risk of the development of overweight (including dietary intake, physical activity, and sedentary behaviour) will be reviewed while taking into consideration the influence of the familial environment, the school environment, and the community and larger social environments. It is concluded that future research needs to adopt a broader contextual approach in order to understand and intervene against the processes leading to the development of overweight among children and that the use of theories or paradigms such as EST will facilitate developing and testing models of causal processes.

Family environmental factors influencing the developing behavioral controls of food intake and childhood overweight

Although a large body of research has assessed direct genetic links between parent and child weight status, relatively little research has assessed the extent to which parents (particularly parents who are overweight) select environments that promote overweight among their children. Parents provide food environments for their children's early experiences with food and eating. These family eating environments include parents' own eating behaviors and child-feeding practices. Results of the limited research on behavioral mediators of familial patterns of overweight indicate that parents' own eating behaviors and their parenting practices influence the development of children's eating behaviors, mediating familial patterns of overweight. In particular, parents who are overweight, who have problems controlling their own food intake, or who are concerned about their children's risk for overweight may adopt controlling child-feeding practices in an attempt to prevent overweight in their children. Unfortunately, research reveals that these parental control attempts may interact with genetic predispositions to promote the development of problematic eating styles and childhood overweight. Although the authors have argued that behavioral mediators of family resemblances in weight status, such as parents' disinhibited or binge eating and parenting practices are shaped largely by environmental factors, individual differences in these behaviors also have genetic bases. A primary public health goal should be the development of family-based prevention programs for childhood overweight. The findings reviewed here suggest that effective prevention programs must focus on providing anticipatory guidance on parenting to foster patterns of preference and food selection in children more consistent with healthy diets and promote children's ability to self-regulate intake. Guidance for parents should include information on how children develop patterns of food intake in the family context. Practical advice for parents includes how to foster children's preferences for healthy foods and how to promote acceptance of new foods by children. Parents need to understand the costs of coercive feeding practices and be given alternatives to restricting food and pressuring children to eat. Providing parents with easy-to-use information regarding appropriate portion sizes for children is also essential as are suggestions on the timing and frequency of meals and snacks. Especially during early and middle childhood, family environments are the key contents for the development of food preferences, patterns of food intake, eating styles, and the development of activity preferences and patterns that shape children's developing weight status. Designing effective prevention programs will, however, require more complete knowledge than currently available regarding behavioral intermediaries that foster overweight, including the family factors that shape activity patterns, meals taken away from home, the impact of stress on family members' eating styles, food intake, activity patterns, and weight gain. The research presented here provides an example of how ideas regarding the effects of environmental factors and behavioral mediators on childhood overweight can be investigated. Such research requires the development of reliable and valid measures of environmental variables and behaviors. Because childhood overweight is a multifactorial problem, additional research is needed to develop and test theoretic models describing how a wide range of environmental factors and behavioral intermediaries can work in concert with genetic predispositions to promote the development of childhood overweight. The crucial test of these theoretic models will be in preventive interventions.

Does fat intake predict adiposity in healthy children and adolescents aged 2--15 y? A longitudinal analysis

OBJECTIVE

To investigate the relationship between food energy and macronutrient intake and body fatness assessed up to seven times between 2 and 15 y of age.

DESIGN

Prospective, observational study. Generalised linear estimating equations were used to evaluate the longitudinal relationship between body fatness and macronutrient intake. Regression analysis was used to assess whether body fatness at a particular age was predicted by intake at any of the previous ages.

SETTING

Community-based project in Adelaide, South Australia.

SUBJECTS

In all 143--243 subjects from a representative birth cohort of healthy children recruited in 1975 and followed over 15 y.

MAIN OUTCOME MEASURES

The dependent variables were body mass index (BMI), triceps (TC) and subscapular (SS) skinfolds, expressed as standard deviation (s.d.) scores at each age. The predictor variables were energy-adjusted macronutrient intake and total energy intake, estimated from a 3--4 day diet diary, the previous corresponding measure of body fatness, sex and parental BMI, TC or SS.

RESULTS

Across 2--15 y energy-adjusted fat and carbohydrate intakes were respectively directly and inversely related to SS skinfold measures but not to either BMI or TC skinfold. The best predictor of fatness was previous adiposity, with the effect strengthening as the age interval shortened. Parental BMI, maternal SS and paternal TC contributed to the variance of the corresponding measure in children at some but not all ages.

CONCLUSIONS

The current level of body fatness of the child and parental adiposity are more important predictors than dietary intake variables of risk of children becoming or remaining overweight as they grow.