Micro-environmental and socio-demographic determinants of childhood obesity

Determinants of health and well-being in adolescents : Review of sex differences with a focus on boys

A wide variety of variables determine health and well-being in adolescence. How these variables may differ in relation to gender or sex is often not clear. In addition, research on sex differences often focuses on females rather than males. This review gives an overview on the literature with respect to possible gender/sex-specific determinants and correlates of health and well-being in adolescent boys. The search strategy used the approach of a narrative review, which led to 17 papers being included. The data synthesis employed a qualitative and descriptive analysis approach. We found sex differences in three categories: clinical symptoms, health and well-being, and risk behavior. The results show a variety of determinants that lead to sex differences in health outcomes, such as peer relations, social economic status, physical activity and coping styles. Strengths and limitations of the literature and implications for future research are discussed.

Social influences on adolescents' dietary behavior in Catalonia, Spain: A qualitative multiple-cases study from the perspective of social capital

Adolescence has been referred to as the last best chance to prevent adult non-communicable diseases. Gaining further evidence on the psychosocial determinants of health behaviors, particularly the impact of peers, social networks and media on diet, is necessary to develop appropriate preventive strategies. Based on a multiple-cases study, our aim was to discuss the social influences on adolescents' dietary behavior from a social capital perspective. Participants were reached through four high-schools in different Catalan rural-urban and socioeconomic contexts. Our results confirm the different layout of social capital in the community, school, peers and family. In our sample, family and peers are the most influent sources of social capital in relation to dietary behaviors, inducing both protective and damaging effects.

Socioeconomic position and childhood-adolescent weight status in rich countries: a systematic review, 1990-2013

Background

Childhood obesity is a major problem in rich countries due to its high prevalence and its harmful health consequences. An exploratory analysis conducted in the PubMed database highlighted that the number of papers published on the relationship between socioeconomic position (SEP) and childhood-adolescent weight status had risen substantially with respect to an earlier review which had covered the period 1990–2005.

Methods

To describe the findings on the relationship between SEP and childhood-adolescent weight status in papers published in rich countries from 1990 through 2013, studies were identified in the following databases: PubMed; Web of Knowledge (WOK); PsycINFO; Global Health; and Embase. We included observational studies from the 27 richest OECD countries, which covered study populations aged 0 to 21 years, and used parental education, income and/or occupation as family SEP indicators. A total of 158 papers met the inclusion criteria and reported 134 bivariable and 90 multivariable analyses.

Results

Examination of the results yielded by the bivariable analyses showed that 60.4 % of studies found an inverse relationship, 18.7 % of studies did not found relationship, and 20.9 % of studies found a relationship that varied depending on another variable, such as age, sex or ethnic group; the corresponding percentages in the multivariable analyses were 51.1, 20.0 and 27.8 %, respectively. Furthermore, 1.1 % found a positive relationship.

Conclusion

The relationship between SEP and childhood-adolescent weight status in rich countries is predominantly inverse and the positive relationship almost has disappeared. The SEP indicator that yields the highest proportion of inverse relationships is parents’ education. The proportion of inverse relationships is higher when the weight status is reported by parents instead using objective measurements.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0443-3) contains supplementary material, which is available to authorized users.

Psychosocial perspectives and the issue of prevention in childhood obesity

A dramatic increase in childhood overweight/obesity has been recognized globally over the past 50 years. This observed increase may reflect genetic, as well as psychological, environmental, and socio-cultural influences. In the first part of this review, we present an updated summary of the psychosocial factors associated with this change and discuss possible ways in which they operate. Among these factors, lower socio economic status (in both industrialized and non-industrialized countries), being female, belonging to a minority group, and being exposed to adverse life events may all be associated with a greater risk of childhood overweight/obesity. These influences may be mediated via a variety of mechanisms, in particular above-average food intake of low nutritional quality and reduction in physical activity. Other important psychosocial mediators include the influence of the family and peer environment, and exposure to the media. In the second part of the review, we discuss the potential of psychosocial prevention programs to intervene in the processes involved in the rise of childhood overweight/obesity. Two points are emphasized. First, prevention programs should be multidisciplinary, combining the knowledge of experts from different professions, and taking into consideration the important role of the family environment and relevant influential social organizations, particularly school. Second, effective change is unlikely to occur without large-scale programs carried out on a public policy level.

Socioeconomic factors and childhood overweight in Europe: results from the multi-centre IDEFICS study

What is already known about this subject Overweight and obesity can be linked to different parental socioeconomic factors already in very young children. In Western developed countries, the association of childhood overweight and obesity and parental socioeconomic status shows a negative gradient. Ambiguous results have been obtained regarding the association between socioeconomic factors and childhood overweight and obesity in different countries and over time. What this study adds European regions show heterogeneous associations between socioeconomic factors and overweight and obesity in a multi-centre study with highly standardized study protocol. The strength of association between SES and overweight and obesity varies across European regions. In our study, the SES gradient is correlated with the regional mean income and the country-specific Human development index indicating a strong influence not only of the family but also of region and country on the overweight and obesity prevalence.

OBJECTIVE

To assess the association between different macro- and micro-level socioeconomic factors and childhood overweight.

METHODS

Data from the IDEFICS baseline survey is used to investigate the cross-sectional association between socioeconomic factors, like socioeconomic status (SES), and the prevalence of childhood overweight. Differences and similarities regarding this relationship in eight European regions (located in Belgium, Cyprus, Estonia, Germany, Hungary, Italy, Spain and Sweden) are explored. 11 994 children (50.9% boys, 49.1% girls) and their parents were included in the analyses.

RESULTS

In five of the eight investigated regions (in Belgium, Estonia, Germany, Spain and Sweden), the prevalence of childhood overweight followed an inverse SES gradient. In the other three regions (in Cyprus, Hungary and Italy), no association between SES and childhood overweight was found. The SES-overweight association in a region was best explained by the country-specific human development index and the centre-specific mean income. For the investigated association between other socioeconomic factors and overweight, no clear pattern could be found in the different regions.

CONCLUSION

The association between socioeconomic factors and childhood overweight was shown to be heterogeneous across different European regions. Further research on nationwide European data is needed to confirm the results and to identify target groups for prevention.

Parental determinants of overweight and obesity in Iranian adolescents: a national study

OBJECTIVE

Overweight among adolescents is not only an important public health problem but also a problem affecting economic growth in developing countries. The aim of this study was to investigate the parental determinants of overweight and obesity in Iranian adolescents at national level.

METHODS

This cross sectional study was conducted within the framework of the Comprehensive Study on Household Food Consumption Patterns and Nutritional Status of IR Iran during 2001-2003. In adolescents, anthropometric indices were defined based on the CDC 2000 cut-off points for age and gender-specific body mass index (BMI). Parental characteristics were collected by questionnaire. Among the 7158 participating households, data on 7908 adolescents aged 11-19 years (3750 girls and 4158 boys) was analyzed.

FINDINGS

The prevalence of overweight (85-94th percentile) in boys and girls was 6.2%, and 8.7%, respectively. The prevalence of obesity (≥95th percentile) among boys and girls was similar (3.3%). Parents' weight status, father's job and parents' education showed significant association with weight status in adolescents. Logistic regression analysis showed that parental overweight and obesity, parental education and father's job were the main parental determinants of overweight and obesity in Iranian adolescents.

CONCLUSION

Parental overweight and obesity, parental education and father's job seem to be the major parental determinants of overweight in Iranian adolescents. Future prevention programs must take these risk factors into account.

[Social disparities in the prevalence of overweight and obesity in adolescents]

INTRODUCTION

Many social factors have a role in determining the risk of overweight/obesity in children and adolescents, and are the main barriers in their management. This study tries to define the effect that some familial and social factors have on the risk of overweight/obesity in children and adolescents.

METHOD

Population sample of 11- and 14-years old children recruited in three Primary Care Centres in Palencia. Their weight, height and skin folds were measured, and information gathered about sport activities, TV watching, and parental data (weight, height, educational status and occupation). Multivariate models were used to analyse the effect of these variables on the weight status and on the body fat.

RESULTS

Three hundred and twenty-two children were included. Prevalence of obesity was 5.6% and that of any degree of overweight was 28.9%. Overweight was not related to educational status or occupation, but it was more often found in males (OR 2.07; 95% CI; 1.12-3.83), in children whose father (OR 2.18; 95% CI; 1.14-4.15) or mother (OR 2.17; 95% CI; 1.18-3.98) were overweight, and in those who spent ≥2 h daily watching TV (OR 2.72; 95% CI; 1.43-5.19), and it was less frequent in 14 than in 11-year old children (OR 0.42; 95% CI; 0.23-0.78). Obesity was only related to a low educational level (OR 19.45; 95% CI; 1.95-193.82).

CONCLUSIONS

Overweight is related with genetic-environmental factors and the modern society way of life, and occurs across the whole social spectrum. But obesity is strongly related to a low educational status of the family, and it still is a marker for health disparities.

Establishing validity and reliability of an instrument using the theory of planned behavior to predict middle school student obesity-related actions

BACKGROUND

Childhood obesity is of concern to many health professionals, parents, teachers, and school administrators because of the negative impact on the child's physical, psychological, and behavioral health. Lack of structured monitoring and evaluation has hindered the development of an evidence base to disseminate best practices in childhood obesity prevention.

PURPOSE

The purpose of this study was to develop a valid and reliable instrument which affirmed the constructs of the Theory of Planned Behavior in relation to nutrition and physical activity behaviors related to childhood obesity.

METHODS

A convenience sample of 242 students participated in the validation of the 129-item instrument, which was administered during class time, and read to students to increase response rate.

RESULTS

Confirmatory factor analysis established instrument validity, with one factor present for each behavior, and factor loadings greater than 0.32. Reliability and test-retest coefficients achieved apriori criteria of 0.70.

DISCUSSION

Truly learning how to gauge nutrition and physical activity levels in children and adolescents has proved to be difficult, yet it is imperative to understand the relationship of the proposed potentially modifiable behaviors and childhood obesity.

Adiponectin and leptin metabolic biomarkers in chinese children and adolescents

Objective. To evaluate leptin and adiponectin as biomarkers of metabolic syndrome (MS) risk factors even in nonobese children/adolescents. Methods. Serum leptin, adiponectin, leptin:adiponectin ratio, lipids, glucose, and insulin concentrations as well as body size parameters and pubertal development were evaluated in a large population of Chinese children/adolescents (n = 3505, 6-18 years, 1722 girls and 1783 boys). Results. Leptin concentration increased while adiponectin decreased with obesity, both were influenced by pubertal development. Central obesity had an additive effect on leptin levels (above obesity alone). Leptin/adiponectin increased 8.4-fold and 3.2-fold in overweight/obesity, and 15.8- and 4.5-fold with obesity plus MS, in early and late puberty, respectively. Even in normal weight children/adolescents, higher leptin and lower adiponectin concentrations associated with increased risk profile. Conversely, overweight/obese with lower leptin or higher adiponectin concentrations had a less compromised metabolic profile. Conclusion. Leptin, adiponectin, and leptin:adiponectin ratio are informative biomarkers for obesity, central obesity, MS, and abnormal metabolic profile even in normal weight children/adolescents.

Design and evaluation of a treatment programme for Spanish adolescents with overweight and obesity. The EVASYON Study

Background

The prevalence of overweight and obesity (OW/OB) among adolescents worldwide has increased since the 60 s. Spain has reached one of the highest OW/OB prevalence rates among adolescents from European countries. The aim of this methodological paper is to describe the design and evaluation in the EVASYON study (Development, implementation and evaluation of the efficacy of a therapeutic programme for adolescents with OW/OB: integral education on nutrition and physical activity).

Methods/Design

The EVASYON was planned by a multidisciplinary team to treat OW/OB in Spanish adolescents. The EVASYON is a multi-centre study conducted in 5 hospitals in 5 Spanish cities (Granada, Madrid, Pamplona, Santander and Zaragoza) and two hundred and four OW/OB Spanish adolescents were recruited for this intervention. The treatment was implemented for approximately one-year follow-up. The adolescents were treated in groups of a maximum of 10 subjects; each group had 20 visits during the treatment period in two phases: intensive during the first 2 months (1^st to 9^th visits), and extensive during the last 11 months (10^th to 20^th visits). In order to assess the efficacy of the treatment, 8 dimensions were measured: diet; physical activity and fitness; eating behaviour; body composition; haematological profile; metabolic profile; minerals and vitamins; immuno-inflammatory markers. Moreover, genetic polymorphisms were also determined.

Discussion

The treatment programme developed in the EVASYON study was designed as a national pilot study to be implemented as an effective treatment for adolescents with OW/OB into the Spanish Health Care Service.

Meta-Analysis of School-Based Childhood Obesity Interventions in the U.K. and U.S

This study conducted a meta-analysis on the outcome indicator of body mass index from published school-based childhood obesity interventions done in the United States and the United Kingdom between 2000 and 2007. Electronic databases were searched for school-based childhood obesity interventions and a total of five studies were analyzed. The results of the pooled estimate of reviewed studies were not significant for the outcome measure body mass index at p < 0.05 level for fixed (effect estimate –0.0649 (95% CI: –0.29, 0.16)) as well as random effects (effect estimate 0.179 (95% CI: –0.38, 0.72)) models. In conclusion, it can be said that current school-based childhood obesity interventions do not seem to modify body mass index.

Fatores de risco para sobrepeso entre adolescentes: análise de três cidades brasileiras

OBJETIVO: Realizar análise comparativa de fatores de risco para sobrepeso em adolescentes de três cidades brasileiras, Pelotas, São Paulo e Goiânia. MÉTODOS: Os três bancos de dados são provenientes de estudos com delineamento do tipo caso-controle, que investigaram fatores de risco para sobrepeso/obesidade entre adolescentes das três cidades. Classificaram-se os adolescentes como sobrepeso quando o Índice de Massa Corporal estava acima do percentil 85 em relação ao padrão de referência do National Center for Health Statistcs. Procedeu-se à análise multivariada com modelo hierárquico de regressão logística. RESULTADOS: Foram estudados 903 adolescentes pós-púberes (443 casos e 460 controles). A análise não-ajustada dos três bancos de dados combinados aumentou o poder das associações quando meninos e meninas foram considerados separadamente. Educação materna menor ou igual a 8 anos duplicou o risco de sobrepeso entre meninas; obesidade dos pais esteve fortemente associada ao sobrepeso dos adolescentes; tempo de televisão maior ou igual a 4 horas associou-se ao sobrepeso apenas entre meninas; consumo de gordura visível da carne aumentou o risco de sobrepeso entre os meninos em 70% e consumo de frituras apresentou associação inversa entre as meninas. Finalmente, o consumo de álcool esteve significante e inversamente associado ao sobrepeso entre meninos. CONCLUSÃO: Meninas pós-púberes, provenientes de famílias com baixa escolaridade, devem receber atenção especial durante o planejamento e a execução de estratégias de prevenção e controle do sobrepeso.

Small birth weight and later body composition and fat distribution in adolescents: the Avena study

OBJECTIVE

To assess the association between birth weight and body composition and fat distribution in adolescents, and to test the possible sex-specific effect in these relationships.

METHODS AND PROCEDURES

A total of 1,223 adolescents 13-18.5 years old (553 male adolescents and 670 female adolescents) born at >35 weeks, were selected from a cross-sectional multicenter study conducted in five Spanish cities in 2000-2002. BMI was calculated from weight and height. Triceps and subscapular skinfold thickness (ST) were measured on the left side, and fat mass (FM) and fat-free mass (FFM) were estimated according to the equations of Slaughter et al. Subscapular skinfold adjusted by tricipital (ST) and waist circumference were used as markers of central adiposity.

RESULTS

Birth weight Z-score was positively associated with FFM in female adolescents (P<0.001), but not in male adolescents, after controlling for age, pubertal stage, gestational age, socioeconomic status, physical activity, and current height (P<0.001 for interaction between adjusted birth weight Z-score and sex). Adjusted birth weight Z-score was inversely associated with central adiposity in male and female adolescents as measured by ST (P=0.026).

DISCUSSION

These results provide further evidence that gender has an important influence on the programming effect of birth weight on later FFM in adolescents because the effect was only observed in female adolescents. Our results suggest that small size for gestational age at birth could program more central subcutaneous fat deposition in adolescents of both sexes, but further research is needed on this issue.

Is thinness more prevalent than obesity in Portuguese adolescents?

BACKGROUND & AIMS

There is little information regarding the prevalence of thinness in European adolescents. This was assessed in a convenience sample of children and adolescents from the Lisbon area (Portugal).

METHODS

Cross-sectional study including 2494 boys and 2519 girls aged 10-18 years. Body mass index (BMI), waist and hip were measured using standardized methods; thinness was defined using international criteria. Body fat was assessed by bioelectrical impedance.

RESULTS

In girls, prevalence of thinness, overweight and obesity were 5.6%, 19.7% and 4.7%, respectively, whereas the corresponding numbers in boys were 3.9%, 17.4% and 5.3%. Prevalence of thinness increased whereas obesity decreased with age: from 1.5% to 7.6% for thinness and from 9.2% to 3.8% for obesity in girls aged 10 and 18, respectively. In boys, the corresponding trends were from 0% to 7.3% for thinness and from 10.6% to 3% for obesity. After adjusting for age, differences were found between BMI groups for weight, body fat percentage, fat mass, lean mass, waist and hip, while no differences regarding height were found between thin and normal weight participants.

CONCLUSIONS

The prevalence of thinness is more frequent than obesity after age 14 in girls and 16 years in boys. Thinness is associated with a decreased body weight and body fat, whereas no consistent effect on height was noted.

Assessing, understanding and modifying nutritional status, eating habits and physical activity in European adolescents: The HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study

Objectives

To identify the main knowledge gaps and to propose research lines that will be developed within the European Union-funded ‘Healthy Lifestyle in Europe by Nutrition in Adolescence’ (HELENA) project, concerning the nutritional status, physical fitness and physical activity of adolescents in Europe.

Design

Review of the currently existing literature.

Results

The main gaps identified were: lack of harmonised and comparable data on food intake; lack of understanding regarding the role of eating attitudes, food choices and food preferences; lack of harmonised and comparable data on levels and patterns of physical activity and physical fitness; lack of comparable data about obesity prevalence and body composition; lack of comparable data about micronutrient and immunological status; and lack of effective intervention methodologies for healthier lifestyles.

Conclusions

The HELENA Study Group should develop, test and describe harmonised and state-of-the-art methods to assess the nutritional status and lifestyle of adolescents across Europe; develop and evaluate an intervention on eating habits and physical activity; and develop and test new healthy food products attractive for European adolescents.

Prevalence and determinants of obesity in children in public schools of Sintra, Portugal

OBJECTIVE

To assess the prevalence of and the factors related to overweight and obesity in a sample of children from the region of Sintra, Portugal.

METHODS AND PROCEDURES

Cross-sectional study, stratified for freguesia with random selection of schools. Height, weight, triceps skinfold, upper arm and waist circumferences were measured, and overweight/obesity defined according to international criteria. Breast-feeding, number of daily meals and parents' height and weight data were also collected.

RESULTS

One thousand two hundred and twenty-five children aged 6-10 years were assessed. Overall prevalence of overweight and obesity was 35.6% (23% overweight and 12.6% obesity). Overweight or obese children had higher triceps skinfold, upper arm circumference, arm muscle area, and waist circumference than their normal weight counterparts (P < 0.001). On multivariate analysis, relatively to a child without obese progenitors, a child with one obese progenitor had an obesity risk multiplied by 2.78 (95% confidence interval (CI): 1.76-4.38), while a child with two obese progenitors had a risk multiplied by 6.47 (95% CI: 5.59-16.19). Conversely, being picky was significantly related with a smaller risk of obesity: for boys, odds ratio (OR) = 0.15 (95% CI: 0.04-0.63); for girls, OR = 0.19 (95% CI: 0.06-0.64). Finally, no relationships were found between obesity, birth weight, birth height or breast-feeding.

DISCUSSION

Prevalence of overweight and obesity are elevated among children of the Sintra region in Portugal compared to most other regions of Europe. The relationship with the parents' nutritional state stresses the need to target families for preventing obesity.

Effect of the Ala12 allele in the PPARgamma-2 gene on the relationship between birth weight and body composition in adolescents: the AVENA study

The intent of this study was to assess whether the effect of birth weight on later body composition is modified by Pro12Pro, Pro12Ala, and Ala12Ala genotypes of the peroxisome proliferator-activated receptor gamma-2 (PPARgamma-2) gene. The PPARgamma-2 gene polymorphism was genotyped in 273 adolescents aged 13-18.5 y, born at term and whose birth weight was known. They were selected from a cross-sectional multicenter study conducted in five Spanish cities in 2000-2002. Body mass index (BMI) was calculated from weight and height measurements, and body composition and fat distribution were estimated from skinfold thickness. A total of 229 subjects (111 males and 118 females) carried the Pro12Pro genotype and 44 (22 males and 22 females) the Pro12Ala and Ala12Ala PPARgamma-2 genotypes. In the Pro12Pro group, birth weight Z score was positively associated with both fat-free mass (FFM) (p < 0.05) and fat mass (FM) (p < 0.05), but these relationships disappeared after controlling for age, gestational age, socioeconomic status (SES), physical activity, Tanner stage, sex, and BMI. In the Ala12 group, birth weight Z score was positively associated with FFM (p < 0.01), and this relationship remained significant after controlling for confounding variables (p < 0.05). Small body weight at birth may program lower FFM in adolescents carrying the Ala12 allele in the PPARgamma-2 gene.

Adiposity, physical activity, and physical fitness among children from Aragón, Spain

OBJECTIVE

The main purpose of this study was to determine the relationship between physical activity (PA) levels and adiposity. The secondary purpose was to assess the effect of physical fitness and living area on adiposity.

RESEARCH METHODS AND PROCEDURES

A cross-sectional study was carried out in a regional representative sample of 1068 children 7 to 12 years of age. Anthropometric and physical fitness values (including BMI, aerobic capacity, strength levels, velocity assessment, and flexibility) were measured in all children.

RESULTS

The prevalence of being overweight and obese in the entire sample was 31% and 6%, respectively. No difference between urban and rural children was found. The proportion of boys who were classified as overweight and obese was similar in physically active and sedentary (non-physically active) groups. However, physically active girls tended to show lower obesity prevalence compared with their sedentary counterparts (p = 0.06). In girls, the sum of the 6 skinfolds thickness (SSF) measurements was lower in the physically active group when compared with the non-physically active group (p < 0.05); however, this effect was not observed in boys. Multiple regression analysis revealed that the level of physical activity (PA) had a significant effect on BMI and SSF in boys but not in girls, while maximal oxygen uptake (VO2max) was significantly related to adiposity in both sexes.

DISCUSSION

Regular participation in at least 2 hours per week of sports activities on top of the compulsory education program is associated with better physical fitness and lower whole body adiposity. In the children included in our study, among all physical fitness variables, VO2max showed the strongest relationship with BMI and fat mass assessed by means of skinfold measurements.

Trends and sociocultural factors for childhood overweight in La Reunion Island

OBJECTIVE

To examine time trends (study 1) and sociocultural factors associated with childhood overweight (study 2) in La Reunion Island.

DESIGN

Study 1: a longitudinal analysis of anthropometric data available from health services in the town of Saint-Pierre. Study 2: a case - control study.

SUBJECTS

Study 1: 1753 children born between 1977 and 1996. Study 2: 101 six-year old overweight children sex-matched with 101 non-overweight children.

MEASUREMENTS

Study 1: overweight at birth (birth weight>4 kg) and at age 4 and 6 using French references and references from the International Obesity Task Force. Study 2: parental and perinatal data, child's lifestyle and representation of food, all collected from the mother.

RESULTS

Study 1: a dramatic increase in the prevalence rate of overweight at 4 and at 6 is observed, more severe in girls. Study 2: multivariate logistic regressions showed that mother's overweight was the only variable significantly associated with overweight in both the sexes. The other associated factors were related to sociocultural and family features and sedentarity. Logistic probability functions derived from these data are proposed as a tool for detection of at risk families.

CONCLUSION

Our results show the need for a targeted prevention of overweight. We offer a proposal based on education and behaviour modification in La Reunion Island.

Overweight and obesity among Iranian female adolescents in Rasht: more overweight in the lower social group

OBJECTIVE

This study aimed to investigate the frequency of overweight and obesity among Iranian adolescent girls aged 14-17 years and its possible association with maternal education in Rasht city in 2005.

DESIGN

A cross-sectional survey on 1054 schoolgirls.

SETTING

High schools in Rasht city, Iran.

METHODS

A multistage sampling method was used and 1054 randomly selected schoolgirls were studied. Data on age and mother's years of schooling were collected by questionnaire and body weight and height were measured. Overweight and obesity were defined using age- and sex-specific body mass index (BMI) cut-off points proposed by the International Obesity Task Force (IOTF), and compared with 85th and 95th BMI percentile curves of the IOTF reference population, respectively. Data analyses included two groups based on mother's years of schooling: less educated ( < 12 years) and more educated ( > or = 12 years).

RESULTS

The overall prevalence of overweight and obesity in this population was 21.9 and 5.3%, respectively. Results of logistic regression analysis showed that the risk of overweight was higher for lower age group (odds ratio = 2.0, 95% confidence interval 0.18-3.09). Overweight was more common in girls with less educated mothers than in girls with more educated mothers (26.0 vs. 19.8%, P = 0.03).

CONCLUSION

These data indicate that overweight is highly prevalent among adolescent girls, especially in lower social groups in Rasht, and the rate is exceeding those reported in other parts of the country. Preventive strategies need to be adopted to combat the epidemic of overweight and obesity in this population.

Predictor factors for childhood obesity in a Spanish case-control study

OBJECTIVE

The aim of this study was to identify and characterize factors associated with childhood obesity risk related to lifestyle and perinatal life influences (dietary pattern, physical activity, family history of obesity, breast-feeding, sedentary behavior, and birth weight) in a case-control study design.

METHODS

Cases were 185 obese (body mass index >97th percentile) children and adolescents (6-18 y old) from the Navarra region of Spain and control subjects were matched by sex and age. Anthropometric data were collected, and a personal interview about lifestyle parameters (dietary patterns, physical activity, family history of obesity, breast-feeding and sedentary behaviors) was performed with each participant. Conditional logistic regression was used to identify predictive factors of obesity.

RESULTS

Leisure time physical activity proved to be a protector factor against obesity (odds ratio [OR] 0.94, 95% confidence interval [CI] 0.92-0.96), whereas family history of obesity (OR 4.18, 95% CI 2.20-8.62), watching television (OR 2.02, 95% CI 1.09-3.77), and sugar-sweetened beverage consumption (OR 1.74, 95% CI 1.05-2.89) were associated with a higher obesity risk.

CONCLUSION

Our results suggest that leisure time physical activity, family history of obesity, watching television, and sugar-sweetened beverage consumption are important predictive variables for childhood obesity, whereas other factors including breast-feeding, birth weight, and time spent sleeping did not appear to play an important role in the development of childhood obesity.

Family and school determinants of overweight in 13-year-old Portuguese adolescents

AIMS

To identify familial and school determinants of overweight in 13-year-old adolescents.

METHODS

All 27 public and 19 (79%) private schools allowed to contact age eligible students, 77.5% accepting to participate (1116 girls, 1045 boys). Self-administered questionnaires were completed and physical examination performed, including weight and height measurements. Overweight (> 95th percentile) and at risk of overweight (85th-95th) were defined using CDC standards. Its determinants were identified using logistic regression models, entering parents' education and all variables significantly associated in crude analysis.

RESULTS

Prevalence of overweight (10.2%) and at risk of overweight (16.5%) was not influenced by type of school, vending machines and number of school canteen meals. In girls, the prevalence of body mass index (BMI) > 85th percentile increased significantly with decreasing age at menarche (45.7% if menstruating before 11-year and 13.2% when pre-menarche), and increasing parental BMI or time spent on sedentary activities. In multivariate analysis, age at menarche and increasing parental BMI remained significant risks in girls. In boys, besides parental BMI, ever smoking, sleeping < 9 h and sedentary leisure activities were significant determinants.

CONCLUSIONS

Food offered at school had no significant impact on adolescents overweight, which was mainly dependent on parental anthropometrics and leisure time activities.

Screening Performances of the International Obesity Task Force Body Mass Index Cut-Off Values in Adolescents

OBJECTIVE

To try to improve the International Obesity Task Force (IOTF) BMI cut-off values, in terms of prediction of body fat percentage assessed by dual-energy X-ray absorptiometry (DXA), in adolescents.

METHODS

Cross-sectional survey of the adolescents from the city of Zaragoza (Spain). For this analysis we have included 286 adolescents (116 boys and 170 girls) aged 13.0-17.9 years. Body mass index (BMI) was calculated as body weight (kg), divided by height (m) squared. The percentage of body fat (BF%) was estimated by the use of DXA.

RESULTS

We have calculated, new BMI cut-off values (AVENA cut-offs) to predict BF%, for boys and girls in each age group. In male adolescents, sensitivity was higher with the IOTF cut-offs (0.71, 95th C.I.: 0.44, 0.90) than with the AVENA ones (0.53, 95th C.I.: 0.28, 0.77), and specificity was very similar with both cut-off values (0.86 and 0.88, respectively), the differences being not statistically significant. In girls, both sensitivities (0.75 and 0.79, respectively) and specificities (0.90 and 0.92, respectively) were very similar with both cut-off values, and the differences, not significant.

CONCLUSIONS

Optimization of the IOTF BMI cut-off values, in terms of BF%, seems not to be possible in adolescents. The IOTF criteria should be used only for overweight and obesity screening; however, in clinical settings, a more accurate measure of body fat should be recommended.

Early programming of body composition and fat distribution in adolescents

Size at birth and early postnatal growth are determinants of adult height and BMI. The aim of this study was to evaluate the effect of birth weight on body composition and fat distribution in a group of Spanish adolescents. Current body composition was assessed by both skinfold thickness and dual X-ray absorptiometry in 234 adolescents born at term (140 girls and 94 boys), now aged 13-18 y and living in the city of Zaragoza. Relative fat distribution was estimated using the ratio of the subscapular to triceps skinfolds (S:T). Birth weight and gestational age were assessed by a questionnaire. Birth weight was inversely associated with the S:T ratio (P < 0.05) in boys and directly associated with bone mass (P < 0.01) and fat-free mass (P < 0.05) in girls. This association was independent of factors such as age, Tanner stage, gestational age, socioeconomic status, physical activity, and height. In conclusion, our data support the hypothesis that impaired fetal growth, measured by birth weight, may be related to central fat distribution in boys and decreased bone and fat-free mass in girls.

Inflammatory mediators in overweight and obese Spanish adolescents. The AVENA Study

OBJECTIVE

The aim of this study was to clarify if there is an association between overweight and a state of chronic, low-grade inflammation in adolescents.

DESIGN

The study is a part of the cross-sectional multicenter study AVENA, designed to evaluate the nutritional status of a representative sample of Spanish adolescents. The adolescents were divided into two groups: (1) nonoverweight and (2) overweight/obesity using the International Obesity Task Force (IOTF) standards.

SUBJECTS

A geographically representative subsample of the AVENA study including 493 Spanish adolescents, aged 13-18 y (236 females/257 males), participated in this study.

MEASUREMENTS

Serum C-reactive protein (CRP) and in vitro production of interleukin 6 and tumor necrosis factor alpha were measured, together with a detailed anthropometry.

RESULTS

The inflammatory markers showed generally higher values in subjects with overweight/obesity than in those with nonoverweight, with only CRP showing significant differences (the means were 0.83 and 1.27 mg/l in the nonoverweight and overweight/obesity groups, respectively).

CONCLUSION

Although we have not studied if adolescent overweight and obesity play an initiating role in the development of future diseases, we suggest it may induce a chronic low-grade inflammatory state, which points out the importance of maintaining an appropriate body weight, to avoid obesity-related diseases in adulthood.