Comparison of overweight and obesity prevalence in school-aged youth from 34 countries and their relationships with physical activity and dietary patterns

The purposes of this systematic review were to present and compare recent estimates of the prevalence of overweight and obesity in school‐aged youth from 34 countries and to examine associations between overweight and selected dietary and physical activity patterns. Data consisted of a cross‐sectional survey of 137 593 youth (10–16 years) from the 34 (primarily European) participating countries of the 2001–2002 Health Behaviour in School‐Aged Children Study. The prevalence of overweight and obesity was determined based on self‐reported height and weight and the international child body mass index standards. Logistic regression was employed to examine associations between overweight status with selected dietary and physical activity patterns. The two countries with the highest prevalence of overweight (pre‐obese + obese) and obese youth were Malta (25.4% and 7.9%) and the United States (25.1% and 6.8%) while the two countries with the lowest prevalence were Lithuania (5.1% and 0.4%) and Latvia (5.9% and 0.5%). Overweight and obesity prevalence was particularly high in countries located in North America, Great Britain, and south‐western Europe. Within most countries physical activity levels were lower and television viewing times were higher in overweight compared to normal weight youth. In 91% of the countries examined, the frequency of sweets intake was lower in overweight than normal weight youth. Overweight status was not associated with the intake of fruits, vegetables, and soft drinks or time spent on the computer. In conclusion, the adolescent obesity epidemic is a global issue. Increasing physical activity participation and decreasing television viewing should be the focus of strategies aimed at preventing and treating overweight and obesity in youth.     

Prevalence of overweight/obesity and its association with sedentary behavior in children

ObjectiveThe aim of this study was to determine the prevalence of overweight and obesity in children in the northeast region of Portugal, and to examine its association with sedentary behavior.MethodsData were collected on 1786 children (907 boys, 879 girls) aged 6 to 13 years. Body mass index was calculated from measured height and weight (weight in kg/height in m squared). Overweight and obesity were determined using the International Obesity Task Force cutoff values. Sedentary behavior was assessed based on means of transport to and from school and time spent watching TV and playing video games (TVPC).ResultsThe prevalences of overweight and obesity were 22.6% and 9.4% respectively. The differences between the sexes for both overweight and obesity were not significant. Most of the children (78.4%) go to school by car. Boys spend more time on TVPC than girls, both on weekdays and on weekends. The logistic regression model indicated a significant effect of 1.5 hours of TVPC by boys during weekdays (OR=0.246; p=0.015). Boys who spent less than 1.5 hours on weekdays on TVPC were 75.4% less likely to be overweight than those who spent more than 1.5 hours.ConclusionThe prevalence of overweight and obesity was 32%. Only 12.2% of the children spend less than 1.5 hours on TVPC. Boys who spend less than 1.5 hours on TVPC are 75.4% less likely to be overweight/obese than those who spend more than 1.5 hours.     

Watching television is associated with childhood obesity: but is it clinically important?

OBJECTIVE: To assess the impact of television viewing during childhood and adolescence on body mass index (BMI) in children up to the age of 15 years. DESIGN: Unselected birth cohort, assessed at birth and every 2 years from age 3 to 15 years.Subjects:In all, 1037 individuals were assessed at age 3 years. At age 15 years, 976 (95% of living cohort) continued to participate. MEASUREMENTS: Parental estimates of weekday television viewing between age 5 and 11 years. Self-reports of television viewing at age 13 and 15 years. Weight and height were measured at each age to calculate BMI. RESULTS: BMI and prevalence of overweight at all ages were significantly associated with mean hours of television viewing reported in the assessments up to that age. These associations were stronger in girls than boys. The associations remained significant after adjusting for parental body mass indices and socio-economic status. CONCLUSION: Time spent watching television is a significant predictor of BMI and overweight in childhood. Although the effect size appears small, it is larger than the effect sizes commonly reported for nutritional intake and physical activity. Television viewing should be regarded as an important contributing factor to childhood obesity.     

Association of obesity with physical activity, television programs and other forms of video viewing among children in Mexico city.

OBJECTIVE: To assess the association of physical activity, television program viewing and other forms of video viewing with the prevalence of obesity among school children. DESIGN: Cross-sectional study. SUBJECTS: 712 children, 9-16 y old, from a low- and a middle-income town in the Mexico City area. MEASUREMENTS: Children completed a self administered questionnaire to assess time spent in physical activity and television viewing, and diet. Height weight and triceps skinfolds were measured. The outcome variable was obesity, and the covariates were hours of television programs and other video viewing, physical activity, energy intake, percentage of energy from fat, town of location of school, age, gender and perception of mother's weight status. RESULTS: Among 461 children with complete information, 24% were classified as obese. Children reported an average of 4.1 +/- 2.2 h/d watching television (2.4 +/- 1.5 h/d for TV programs and 1.7 +/- 1.5 h/d for video cassette recorder (VCR) or videogames), and 1.8 +/- 1.3 h/d in moderate and vigorous physical activities. Odds ratios (OR) of obesity were 12% higher for each hour of television program viewing per day (OR = 1.12, 95% confidence interval (CI) 1.02,-1.22), and 10% lower for each hour of moderate/vigorous physical activity per day (OR = 0.90, 95% CI 0.83-0.98), controlling for age, gender, town and perception of mother's weight status. Children in the middle-income town had higher adjusted odds of obesity (OR = 2.58, 95% CI 1.47-4.54). CONCLUSION: Physical activity and television viewing, but not VCR/videogames use, were related to obesity prevalence in Mexican children 9-16 y old.     

Secular trends in overweight and obesity among Finnish adolescents in 1977-1999

OBJECTIVE: To study the trends in overweight and obesity among Finnish adolescents in 1977-1999. DESIGN: Mailed surveys every other year. SUBJECTS: Nationally representative samples of 12, 14, 16 and 18-y-olds (n = 64,147, response rate 78.9%). METHODS: Overweight and obesity were measured by body mass index (BMI) and relative weight (RW) based on self-reported height and weight. BMI > or = the 85th percentile cut-off point for BMI in each age- and sex-specific group in the entire data set was considered as overweight, and BMI > or = 95th percentile cut-off point as obesity. RW > or = 110% and > or = 120%, calculated as the individual's weight divided by the mean weight in each age- and sex-specific height percentile group in the entire data set, were considered as overweight and obesity, respectively. The trends in overweight and obesity are described by the change in the 85th and 95th percentile cut-off points of BMI over time. The prevalence of overweight and obesity is also reported using BMI reference values recommended for international comparisons. Because of the similarity of the BMI and the RW criteria in classifying adolescents as overweight and obese, only results based on BMI are presented. RESULTS: Overweight and obesity increased linearly in all sex and age groups from 1977 to 1999. Depending on the age group, the average increase in the 85th percentile cut-off point of the BMI per 10 y was 0.6-1.1 kg/m2 in boys and 0.3-0.7 kg/m2 in girls. The 95th percentile cut-off point of the BMI for boys and girls increased by 1.1-1.6 kg/m2 and by 0.6-1.0 kg/m2 per 10 y, respectively. In boys, the increase in overweight and obesity was largest in the two youngest age groups. In girls, the increase in overweight was largest in the oldest age group, and that of obesity both in the 14 and 18-y-olds. Overweight and obesity increased more in boys than in girls in all age groups except in the 18-y-olds among whom the increase was similar in both sexes. Examination of the entire BMI distribution showed that there was little or no change over time at the lower (5th, 15th) and middle (50th) percentiles, but increasing differences at the upper end of the distribution, the increases in the 95th percentile being even more marked than those in the 85th percentile curves. According to international reference values, the age-standardized prevalence of overweight increased in boys from 7.2 to 16.7%, and in girls from 4.0 to 9.8%, between 1977 and 1999. The prevalence of obesity in boys was 1.1% in 1977 and 2.7% in 1999, and in girls 0.4 and 1.4%, respectively. CONCLUSION: Overweight and obesity increased remarkably among Finnish adolescents from 1977 to 1999. The changes concentrated at the upper end of the BMI distribution, suggesting that factors behind this development have influenced only a part of the adolescent population.     

Prevalence of overweight and obesity among school children in Jena (Germany)

OBJECTIVES: To examine the prevalence and changes in the prevalence of overweight and obesity among school children in Jena (Germany) in the last twenty years and to identify factors associated with childhood overweight. DESIGN: Cross-sectional surveys in 1975, 1985, 1995 and a household questionnaire in 1995. SUBJECTS: Children from schools in Jena, aged 7-14 y, participated (1975 : 1002 boys and 1000 girls; 1985 : 781 boys and 753 girls; 1995 : 989 boys and 912 girls). MEASUREMENTS: Prevalence of overweight or obesity based on the 90th or 97th age- and sex-specific percentile of the body mass index (BMI) developed for French children. In 1995 factors examined in relation to overweight included birth weight, birth length, age-class, number of children in household, occupation of the father, education of the mother and size of flat (apartment). RESULTS: In boys the prevalence of overweight increased from 10.0 to 16.3% and in girls from 11.7 to 20.7% between 1975 and 1995. The prevalence of obesity increased from 5.3 to 8.2% in boys and from 4.7 to 9.9% in girls between 1975 and 1995. However, the peak in the increase of overweight as well as of obesity lie for both sexes between 1985 and 1995. Using logistic regression, statistically significant associations with overweight were found for occupation of the father, birth weight in both sexes and additionally, for size of flat in girls. CONCLUSIONS: Overweight and obesity are increasing health problems among Jena children. Further investigations are needed to explore the influence of factors such as feeding pattern, food habits and physical activity on overweight. Special attention should be paid to the further social development in the society and to the link between low social class and overweight. Through such investigations effective preventive strategies could be developed.     

Trends in television viewing and overweight /obesity among Nepalese women: Findings from 2006, 2011 and 2016 Nepal Demographic and Health Surveys

Background and aimsAssociations between overweight/obesity and television (TV) viewing have been identified in high-income countries, but little evidence is available from low- and middle-income countries. This study examined the trends and correlates of television viewing and overweight/obesity among Nepalese women between 2006 and 2016.Methods and resultsWe analysed the data from 22,161 women aged 15–49 years who took part in Nepal Demographic Health Surveys 2006 (n = 10,115), 2011 (n = 5,881) or 2016 (n = 6,165). Trained staff collected data on TV viewing and sociodemographic attributes from a face-to-face survey while height and weight were measured objectively to determine body mass index. Around 38% of the study participants watched TV at least once a week in 2006, which increased to 49% in 2011 and 46% in 2016. The prevalence of overweight and obesity increased from 8% in 2006 to 14.6% in 2011 and 19.8% in 2016. Compared to those who did not watch TV at all, those watching it at least once a week were at 1.54 (95% CI: 1.02–2.33), 1.79 (95% CI: 1.23–2.60) and 1.46 (95% CI: 1.13–1.88) times higher odds of being overweight/obese in 2006, 2011 and 2016 respectively.ConclusionThe prevalence of TV viewing rose among women in Nepal between 2006 and 2016 and was associated with overweight/obesity, which also increased dramatically over this period. Future studies examining the use of multiple screen devices, daily usage duration and content viewed are recommended to understand better the health impacts of transitions to more sedentary living in Nepal and similar settings.     

The prevention of overweight and obesity in children and adolescents: a review of interventions and programmes

Overweight and obesity are serious, large-scale, global, public health concerns requiring population-based childhood overweight and obesity prevention. The overall objective of this review is to identify aspects of successful childhood overweight prevention programmes. This objective will be met by assessing existing interventions quantitatively as well as qualitatively, identifying efficacy, effectiveness and implementation, and evaluating potential adverse effects of previous studies. This review was limited to school-based studies with a quantitative evaluation using anthropometric outcomes and that intervene on diet or activity-related behaviours. Quantitative and qualitative approaches are used to identify factors related to successful interventions as well as adverse consequences. Sixty-eight per cent of the interventions, or 17 of the 25, were 'effective' based on a statistically significant reduction in body mass index (BMI) or skin-folds for the intervention group. Four interventions were effective by BMI as well as skin-fold measures. Of these, two targeted reductions in television viewing. The remaining two studies targeted direct physical activity intervention through the physical education programme combined with nutrition education. Of the interventions reported here, one was effective in reducing childhood overweight but was also associated with an increase in underweight prevalence. Few other studies reported outcomes for underweight. The majority of overweight/obesity prevention programmes included in this review were effective. Physical education in schools and reducing television viewing are two examples of interventions that have been successful. Because few studies report on underweight prevalence, this review recommends giving more attention to preventing adverse outcomes by reporting the intervention impact on the frequency distribution for both BMI and adiposity measures.     

Long‐term changes in prevalence of overweight and obesity in Czech 7‐year‐old children: evaluation of different cut‐off criteria of childhood obesity

The objective of this paper was an evaluation of change in prevalence of overweight and obesity in Czech children, and a comparison of cut‐off points for body mass index references from the Czech Republic (CzR), International Obesity Task Force and WHO. The authors conducted a survey in 7‐year‐old children, and compared data from 1951, 1981, 1991, 2001 and 2008 (WHO cut‐offs). 2008 data were evaluated according to different cut‐offs. Results showed that since 1951 in boys, overweight prevalence increased from 13.0% in 1951 to 26.8% in 2001, in girls from 10.9% to 22.9%. Obesity increased in boys from 1.7% to 8.3%, in girls from 1.7% to 6.9%. From 2001 to 2008 obesity in boys increased; obesity in girls and overweight in both genders decreased. In 2008 cohort the following values were found: overweight and obesity: CzR criteria, percentage was lowest (14.8% boys and 11.1% girls); WHO criteria, highest prevalence (23.5% boys and 19.5% girls); obesity: lowest ratio International Obesity Task Force criteria (4.4% boys, 3.3% girls), highest ratio boys WHO criteria (10.0%), girls CzR criteria (5.0%). Overweight and obesity prevalence increased in 7‐year‐old Czech children since 1951; since 2001 prevalence is plateauing with exception of boys. Using different body mass index references resulted in marked differences in overweight and obesity prevalence.     

Assessing social differences in overweight among 15- to 16-year-old ethnic Norwegians from Oslo by register data and adolescent self-reported measures of socio-economic status

OBJECTIVE: To determine to what extent self-reported and objective data on socio-economic status (SES) are associated with overweight/obesity among 15 to 16-year-old ethnic Norwegians. DESIGN: A cross-sectional questionnaire study on health and health-related behaviors. SUBJECTS: All school children aged 15-16 years old in 2000 and 2001 in Oslo, Norway. Response rate 88% (n=7343). This article is based on the data from the 5498 ethnic Norwegians. MEASUREMENTS: Self-reported height and weight were used to measure overweight (including obesity) as defined by the International Obesity Task Force cutoffs at the nearest half-year intervals. SES was determined by register data from Statistics Norway on residential area, parental education and income and by adolescent self-reported measures on parental occupation and adolescents' educational plans. RESULTS: The prevalence of overweight/obesity was low, but higher among boys (11%) than among girls (6%). Parental education (four levels) showed the clearest inverse gradients with overweight/obesity (boys: 18, 13, 10 and 7%; girls: 11, 6, 6 and 4%). Parental education remained significantly associated with overweight/obesity when adding occupation and income to the model for the boys, whereas there were no significant associations in the final model for the girls. Overweight/obesity was associated with a lower odds ratio of planning for higher education (college/university) among boys only. CONCLUSION: For the boys, parental education was most strongly associated with overweight/obesity, and the association between overweight/obesity and educational plans appears to imply downward social mobility. The relationships between the various SES measures and overweight/obesity appeared more interrelated for the girls.     

Overweight, obesity and body fat composition in spanish adolescents. The AVENA Study

OBJECTIVE: To describe the prevalence of overweight and obesity in the Spanish adolescent population and its relationship with the socioeconomic status, and to assess their body fat composition and compare these results with previous data from our own country. DESIGN: Cross-sectional multicenter study conducted in five Spanish cities (Granada, Madrid, Murcia, Santander and Zaragoza) in 2000-2002. SUBJECTS: 2,320 adolescents with complete set of anthropometric measurements, 1,192 boys and 1,128 girls. MEASUREMENTS: Body mass index calculated from weight and height measurements, and body fat percentage calculated from skinfold thickness measurements. RESULTS: Overweight + obesity prevalences were 25.69 and 19.13% in boys and girls, respectively. Overweight + obesity prevalence increased in boys from high to medium-low socioeconomic status categories (p = 0.015); meanwhile, there was not a significant effect of socioeconomic status in girls. In males, overweight + obesity prevalence changed from 1985 to 2000-2002 from 13 to 35% and in females from 16 to 32%. The rate of change in overweight + obesity prevalences seems to increase in the last years; from 0.88 (1985 to 1995) to 2.33%/year (1995 to 2000-2002) in males and from 0.5 (1985 to 1995) to 1.83%/year (1995 to 2000-2002) in females. The rate of body fat percentage increase was similar between 1980 and 1995 and between 1995 and 2000-2002: 0.26 and 0.23%/year, respectively, at 13 years of age, and 0.16 and 0.17%/year, respectively, at 14 years of age. CONCLUSION: We observed elevated overweight and obesity prevalences in Spanish adolescents, similar to those observed in other European countries. There is a significant inverse relationship between socioeconomic status and overweight + obesity, but only in boys. The rate of change in overweight prevalence in Spanish adolescents seems to increase, and the rate of increase of body fat percentage seems to be similar as in previous years.     

Physical activity, leisure habits and obesity in first-grade children.

BACKGROUND: Overweight and obesity are already on the rise in early childhood years. The relationships between genetic factors, malnutrition and physical inactivity are the underlying mechanisms. In this study, we examine the association between body indices, motor abilities and active (sport) and passive (television/computer) leisure time activities in a cohort of first-grade pupils. METHODS: The study group consisted of 344 children (51.5% male, 48.5% female). They were 6.8+/-0.4 years old, height was 123.9+/-4.9 cm, weight 24.8+/-5.0 kg, body mass index (BMI) 16.1+/-2.3 kg/m. After determination of the anthropometric data, a fitness test was performed in order to determine motor abilities. Parents were questioned about their children's leisure time activities, using a standardized questionnaire. Differences between BMI groups were evaluated using multivariate ANCOVA, adjusted for gender and age. RESULTS: Based on German BMI references, overweight and obesity were found in 12% of the children. They had poorer results with respect to endurance (P<0.001), leg strength (P=0.002), co-ordination and balance (P=0.045) and spent more leisure time in watching television and at the computer (each P<0.001). No differences were found between their active leisure habits such as club sports. DISCUSSION: Our examinations with first-grade children show no differences in active leisure habits between obese children and their counterparts, although the former had poorer results in motor abilities, but they spend more time on sedentary leisure habits like audiovisual media. A possible explanation is their fewer regular daily activities.     

Parental overweight, socioeconomic status and high birth weight are the major determinants of overweight and obesity in 5-7 y-old children: baseline data of the Kiel Obesity Prevention Study (KOPS)

OBJECTIVES: To identify the major risk factors of overweight and obesity in prepubertal children. DESIGN: Cross-sectional study. SETTING: In all, 32 primary schools in Kiel (248 000 inhabitants), northwest Germany. SUBJECTS: A total of 2631 5-7-y-old German children and their parents. MAIN OUTCOME MEASURES: Weight status, socio-economic status (SES), parental overweight, dietary intake, activity, inactivity and further determinants (birth weight, breast feeding, nutritional status of siblings) of the children. RESULTS: The prevalence of overweight (>/=90th BMI percentile of reference) was 9.2% in boys and 11.2% in girls, respectively. Considered univariately, family-, environment- and development-related determinants showed some relations to overweight and obesity. In multivariate analyses parental overweight, a low SES as well as a high birth weight were the strongest independent risk factors of overweight and obesity in children. Additionally, there were sex-specific risk factors: parental smoking and single households were risk factors in boys, whereas a low activity was associated with obesity in girls. Birth weight was associated with obesity, but not with overweight. The prevalence of obesity reached 29.2% in boys and 33.4% in girls with all the three main risk factors. CONCLUSIONS: Overweight families of low SES have the highest risk of overweight and obese children. Future prevention programmes must also take into account sex-specific risk factors.     

Time spent watching television, sleep duration and obesity in adults living in Valencia, Spain

OBJECTIVE: To analyse the association of time watching television (TV) and physical activity with obesity in the Mediterranean area of Spain with the highest prevalence of obesity. DESIGN: Cross-sectional study. SETTING: Valencia Region in Spain. PARTICIPANTS: A representative sample of 814 men and 958 women, aged 15 y and older, participating in a Health and Nutrition Survey conducted in 1994. MEASUREMENTS: Height and weight were directly measured during home interviews. The outcome measure was obesity, defined as a body mass index > or = 30 kg/m2. Covariates were self-reported hours of TV viewing, physical activity habits, sleeping duration, age, gender, educational level, smoking and marital status. Prevalence odds ratios (POR) estimated by logistic regression were used as effect measures. RESULTS: Obese people reported to spend more time watching TV (mean +/- s.d.: 3.6 +/- 1.5 h/day) than non-obese ones (3.0 +/- 1.4 h/day), and less sleeping time. In multivariate analysis, obesity was associated with TV viewing, sleeping time and physical activity at work. People watching TV > 4 h/day showed a higher adjusted prevalence odds ratio of obesity, POR = 2.38 (95% confidence interval, 1.54-3. 69), compared with those watching TV < or = 1 h/day. People who reported to sleep > or = 9 h/day presented a lower POR of obesity than those sleeping < or = 6 h/day, POR = 0.43 (0.27-0.67). Statistically significant dose-responses were observed for both associations, so that the prevalence odds ratio of obesity was 30% higher for each hour of increased TV viewing and 24% lower for each additional hour of sleeping time. In addition, the prevalence of obesity was lowest among single people, those more physically active at work, and those with a high educational level. CONCLUSION: Time spent watching television and a low physical activity at work were related to obesity in adults. The inverse association between obesity and sleep duration deserves further research.     

Prevalence of obesity and associated complications in China: A cross-sectional,real-world study in 15.8 million adults

Aim

To evaluate the prevalence of overweight/obesity and associated complications from a large, cross-sectional, nationwide database in China.

Materials and Methods

Data were obtained from 519 Meinian health check-up centres across 243 cities. Eligible participants were aged ≥18 years, with a routine check-up in 2019 (N = 21 771 683) and complete height, weight, sex and region data. The unadjusted prevalence rates of overweight/obesity were calculated by age, sex and region. In addition, the nationwide prevalence rates of overweight and obesity were standardized according to the 2010 China census by age group and sex. The prevalence of obesity-related complications by body mass index (BMI) groups was calculated using logistic regression.

Results

There were 15 770 094 eligible participants (median age 40 years; mean BMI 24.1 kg/m²; 52.8% male). By Chinese BMI classification, 34.8% were overweight and 14.1% were obese. Overweight and obesity were more prevalent in male than female participants (standardized: overweight 40.2% vs. 27.4%; obesity 17.6% vs. 9.6%, respectively). The prevalence of assessed complications was higher in participants with overweight/obesity versus those with normal BMI (P < 0.001 for trends). The most prevalent complications in participants with overweight/obesity were fatty liver disease, prediabetes, dyslipidaemia and hypertension. The number of complications increased with higher BMI.

Conclusions

Overweight/obesity and related complications are highly prevalent in this population. These data may better inform management and prevention public health strategies in China.     

The prevalence of overweight and obesity among Danish school children

In 14 Danish municipalities physicians have gathered weight and height data from 7541 9th grade students (86.7% of all students in 9th grade participating). Overall 25.2% of the population were overweight (body mass index > 90th percentile). Boys were more frequently overweight than girls (29.3% vs. 21.1%) (P < 0.05). 14.1% of the boys and 8.2% of the girls were obese (body mass index > 97th percentile). Categorizing the participating municipalities by socioeconomic status students in municipalities with low status had a significantly higher prevalence of overweight than students in municipalities with high status. Overweight and obesity among Danish school children is a major concern and there are significant social differences in the prevalence of overweight.     

Breastfeeding and overweight in childhood: evidence from the Pelotas 1993 birth cohort study

OBJECTIVES: The effect of breastfeeding duration on the prevalence of overweight and on mean weight for height z-score (WHZ) was evaluated in Brazilian children. DESIGN: Prospective population-based birth cohort study. SUBJECTS: In total, 1,273 children aged 4 years, corresponding to a follow-up rate of 87.2%.Measurements:Three explanatory variables were studied: duration of any breastfeeding, duration of exclusive or predominant breastfeeding, and ever breastfeeding. Weight and height were measured using a digital electronic scale and a portable stadiometer. Overweight was defined as WHZ >2 using the National Center for Health Statistics reference curve. RESULTS: Overweight prevalence at the age of 4 years was 10.2% (95% CI 8.4; 11.8). The lowest prevalence (6.5%) was observed among children breastfed for >11 months. Among those breastfed for less than 3 months, the prevalence of overweight was approximately 9.5%. Mean WHZ ranged from 0.38 among children breastfed for less than 1 month to 0.62 among those breastfed for 9-11.9 months. No linear trends were detected in the association between breastfeeding and anthropometric indicators. None of the three breastfeeding variables was significantly associated with the prevalence of overweight or mean WHZ in multivariable analyses. No interactions were detected between breastfeeding and the variables sex, birth weight, socioeconomic status, skin color and pregestational in body mass index. CONCLUSION: Our results do not support the hypothesis that breastfeeding promotion would reduce overweight or obesity in this population. Existing evidence on many other benefits of breastfeeding for the mother and the child supports its continued promotion, protection and support.     

Prevalence of Obesity and Associated Risk Factors Among Adolescents in Ankara,Turkey

Objective: The purpose of this study was to investigate the prevalence of and the risk factors associated with obesity among adolescents in Ankara, Turkey.Methods: The study was conducted in 26 schools in Ankara during the time period from September 2010 to March 2011. A total of 8848 adolescents aged 11-18 years were chosen using a population-based stratified cluster sampling method. Body mass index (BMI) of the participants was compared with the BMI references for Turkish children and adolescents to estimate the prevalence of overweight and obesity. A standardized questionnaire aiming to determine the sociodemographic characteristics, computer use, television (TV) watching, physical activity, and presence of obesity in the family was applied to the study group.Results: The results showed that the overall prevalence of obesity among adolescents was 7.7% (8.4 % for females and 7.0% for males). It was observed that BMI increased as computer use increased. A greater proportion of the overweight and obese adolescents watched TV and use computer for more than 2 hours/day as compared to their normal-weight counterparts. The normal-weight subjects were found to show a higher participation in regular physical activity. Obesity prevalence among the families of obese adolescents was 56.5%.Conclusions: The prevalence of adolescent obesity in Ankara, Turkey is lower as compared to many European countries and to the United States. Computer use, watching TV, physical activity and family factors are important risk factors for obesity.Conflict of interest:None declared.     

Risk factors of obesity in a five year old population. Parental versus environmental factors.

To be more effective, the prevention of obesity in childhood should be focused on the population at risk. The purpose of the present study is firstly to find correlations between certain environmental factors and obesity in childhood, and secondly to measure the influence of the environmental factors after taking the parental history of obesity into account. This case controlled study includes 704 controls vs. 327 cases selected in a population of five year old school children. The anthropometric assessment was completed at school. Obesity was defined as a weight for height > or = 2 s.d. using the French weight charts for French children based on sex and height. Interviews of the parents recorded parental overweight and child birth overweight as 'constitutional' factors and family structure, socio-economic level and daily lifestyle (sleep, TV viewing, after school care, etc.) as 'environmental' factors. The results show that parental overweight and birth overweight are closely related to the child's obesity at five years of age (estimated relative risks 3.1 and 2.4 respectively). The environmental factors which contribute to child obesity are: southern European origin of the mother, snacks, excessive television viewing and, more importantly, short sleep duration (estimated relative risks = 1.9, 1.3, 2.1 and 4.9 respectively). A logistic regression model, after taking parental overweight into account, shows that the relationship between obesity and short sleep duration persists independently of television viewing. The hypotheses raised by these findings are discussed.     

Temporal trends in overweight and obesity in Canada, 1981-1996

OBJECTIVE: To assess changes in the prevalence of overweight and obesity among Canadian children and adults between 1981 and 1996 using recent recommendations for the classification of overweight and obesity. DESIGN: Epidemiological study comparing the prevalence of overweight and obesity from the 1981 Canada Fitness Survey (CFS) to the 1996 National Longitudinal Survey of Children and Youth (NLSCY) and the 1996 National Population Health Survey (NPHS). SUBjECTS: Adults 20-64 y of age and children 7-13 y of age from the CFS, NLSCY and NPHS. MEASUREMENTS: BMI was calculated from directly measured or self-reported body mass and height. For adults 20-64 y of age, overweight and obesity were defined as BMI > or = 25 kg/m2 and BMI > or = 30 kg/m2, respectively. Age- and sex-specific cut-off points for children that correspond to the adulthood categories were used to define overweight and obesity for children 7-13 y of age. RESULTS: The prevalence of overweight increased from 48 to 57% among men and from 30 to 35% among women, while the prevalence of obesity increased from 9 to 14% in men and from 8 to 12% in women. The corresponding increases were from 11 to 33% in boys and from 13 to 27% in girls for overweight and from 2 to 10% in boys and from 2 to 9% in girls for obesity. CONCLUSION: The results indicate dramatic increases in the prevalence of both overweight and obesity in Canada over the last 15 y, and the problem is particularly pronounced among children.