Is obesity associated with a decline in intelligence quotient during the first half of the life course? The Relationship between Obesity and Cognitive Performance in Children: A Longitudinal Study. Cognitively challenging physical activity benefits executive function in overweight children Protocol for systematic reviews of determinants/correlates of obesity-related dietary and physical activity behaviors in young children (preschool 0 to 6 years): evidence mapping and syntheses Food advertising, children’s food choices and obesity: interplay of cognitive defences and product evaluation: an experimental study Physical activity and obesity mediate the association between childhood motor function and adolescents’ academic achievement Assessment of a school-based intervention in eating habits and physical activity in school children: the AVall study Normal weight children have higher cognitive performance – Independent of physical activity, sleep, and diet Dietary behaviors, physical activity and sedentary lifestyle associated with overweight and obesity, and their socio-demographic correlates, among Pakistani primary school children Personal and social-environmental correlates of objectively measured physical activity in Norwegian pre-adolescent children. Independent contribution of overweight/obesity and physical inactivity to lower health-related quality of life in community-dwelling older subjects The effect of family-based multidisciplinary cognitive behavioral treatment in children with obesity: study protocol for a randomized controlled trial Development of socioeconomic inequalities in obesity among Dutch pre-school and school-aged children. Cognitive abilities, androgen levels, and body mass index in 5-year-old children Biology versus environment in low birth weight children. Randomised trial of early diet in preterm babies and later intelligence quotient Pune low birth weight study--cognitive abilities and educational performance at twelve years.
Cross-sectional studies have found that obesity is associated with low intellectual ability and neuroimaging abnormalities in adolescence and adulthood . Some have interpreted these associations to suggest that obesity causes intellectual decline in the first half of the life course . We analyzed data from a prospect i ve longitudinal study to test whether becoming obese was associated with intellectual decline from childhood to midlife . We used data from the ongoing Dunedin Multidisciplinary Health and Development Study , a population -representative birth cohort study of 1,037 children in New Zeal and who were followed prospect ively from birth ( 1972 - 1973 ) through their fourth decade of life with a 95 % retention rate .  Intelligence quotient ( IQ ) was measured in childhood and adulthood . Anthropometric measurements  were taken at birth and at 12 subsequent in-person assessment s. As expected , cohort members who became obese had lower adulthood IQ scores . However , obese cohort members exhibited no excess decline in IQ . Instead , these cohort members had lower IQ scores since childhood . This pattern remained consistent when we accounted for children 's birth weights and growth during the first years of life , as well as for childhood-onset obesity . Lower IQ scores among children who later developed obesity were present as early as 3 years of age . We observed no evidence that obesity contributed to a decline in IQ , even among obese individuals who displayed evidence of the metabolic syndrome and /or elevated systemic inflammation BACKGROUND The relationship between obesity and academic outcomes remains unclear . We evaluated the association between obesity and cognitive performance in US children . METHODS We analyzed two nationally representative prospect i ve cohorts of children in the 1979 National Longitudinal Survey of Youth , ages 2 through 8 at baseline and followed for 6 years , from 1988 to 1994 ( cohort 1 , n=2672 ) and 1994 to 2000 ( cohort 2 , n=1991 ) . The main exposure variable was obesity ( defined as never obese , became obese , always obese , and became nonobese ) . The main outcomes were st and ardized scores on four cognitive assessment s. Univariate regression analyses of test scores on obesity were performed . Fixed-effects regression models , controlling for measured and unmeasured time-invariant confounders , were additionally adjusted for time-variant confounders to analyze the impact of change in obesity status on change in test scores . RESULTS Unadjusted analyses revealed a significant association between obesity and Peabody Individual Achievement Test ( PIAT ) scores . In cohort 1 , always obese children had lower PIAT math scores than never obese children ( β=-7.48 ; p<0.05 ) . Always obese boys had lower PIAT math scores than those who were never obese ( β=-16.45 ; p<0.01 ) . In cohort 2 , PIAT math scores were lower in the became obese category than the never obese category ( β=-4.10 ; p<0.05 ) . Always obese girls had lower PIAT reading scores than those who were never obese ( β=-11.28 ; p<0.01 ) . Fixed-effects models additionally adjusted for Home Observation Measurement of the Environment , Short Form score and height percentile showed no significant relationship between obesity and test scores in either cohort . CONCLUSION Childhood obesity is unlikely to be causally related to cognitive performance Abstract This study tested the association between aerobic fitness and executive function and the impact of enhanced , cognitively challenging physical activity on executive function in overweight and lean children . Seventy children aged 9–10 years were assigned to either a 6-month enhanced physical education programme including cognitively dem and ing ( open skill ) activities or curricular physical education only . Pre- and post-intervention tests assessed aerobic capacity ( Leger test ) and two components of executive function : inhibition and working memory updating ( r and om number generation task ) . Indices of inhibition and memory updating were compared in higher- and lower-fit children and intervention effects were evaluated as a function of physical activity programme ( enhanced vs. curricular ) and weight status ( lean vs. overweight ) . Results showed better inhibition in higher- than lower-fit children , extending the existing evidence of the association between aerobic fitness and executive function to new aspects of children ’s inhibitory ability . Overweight children had more pronounced pre- to post-intervention improvements in inhibition than lean children only if involved in enhanced physical education . Such intervention effects were not mediated by aerobic fitness gains . Therefore , the cognitive and social interaction challenges inherent in open skill tasks , even though embedded in a low-dose physical activity programme , may represent an effective means to promote cognitive efficiency , especially in overweight children Background The aim of these review s is to inform the design and content of interventions to reduce obesity in young children . The behaviors that are associated with obesity/overweight have been studied extensively ; however , the factors associated with these behaviors in young children ( 0 to 6 years ) have not been systematic ally review ed . Over the past few years the focus of obesity prevention has shifted to preschool children because of the high prevalence of obesity at school entry and recognition that habits formed in early life could track into adulthood . In order to develop effective interventions and change behavior , it is important to underst and the factors that are associated with those behaviors . For example , we need to underst and whether it would be more important to target the family , childcare setting s or the wider environment and identify the most effective way of changing these energy balance related behaviors . Methods / Design Quantitative ( intervention and observational ) and qualitative literature on determinants/correlates of fruit and vegetable intake , sugar sweetened beverage and other unhealthy diet intake , and physical activity and sedentary behaviors in young children will be systematic ally identified , mapped and review ed . A common search strategy ( no language or period restrictions ) will be used to identify papers from eight electronic data bases and this will be supplemented by h and - search ing . Next , studies in developed countries that examine the factors associated with these behaviors in children aged 0 to 6 years ( at baseline ) will be screened and mapped descriptively followed by in-depth data extraction , quality assessment and synthesis . Data from quantitative studies will be summarized using either forest plots or harvest plots and narrative synthesis , and qualitative studies using thematic analysis . Qualitative evidence will be integrated with the quantitative evidence , using a parallel synthesis approach , to provide a deeper underst and ing of effective strategies to influence these energy balance related behaviors . Discussion In addition to updating and mapping current research , these review s will be the first to comprehensively synthesize and integrate both the quantitative and qualitative evidence pertaining to determinants/correlates/barriers/facilitators of obesity related behaviors in this young age group ( 0 to 6 years ) with the aim of informing future interventions . Systematic review registration International Prospect i ve Register for Systematic Review s ( PROSPERO ) Registration number : Objectives : To investigate the role of product evaluations , nutritional and persuasion knowledge on children ’s food choices conducted because of limited evidence about the role of product evaluations on consumer choices in conjunction with cognitive defences . Design : A r and omised controlled 2 × 2 factorial experiment with an exposure to a food and a control ( toy ) advertisement conducted in a non-laboratory setting at an annual event traditionally visited by families . Subjects : Children aged 7–13 years with biometric/weight data representative of the general Australian population . Measurements : Height and weight ( converted into body mass index z-scores ) measured in addition to children ’s nutritional and persuasion knowledge , product evaluations , age and gender . Results : The factors that undermine children ’s cognitive defences relate to taste , social appeal of foods and low nutritional and persuasion knowledge . An interplay between the above-mentioned factors was also observed , identifying four groups among young consumers , alluding to a complex and at times impulsive nature of children ’s decisions : ( 1 ) knowledgeable children with less positive product evaluations choosing a healthy snack ; ( 2 ) knowledgeable but hedonism-oriented children seeking peer conformity choosing an advertised product ; ( 3 ) knowledgeable children who chose a snack belonging to the same product category ; and ( 4 ) less knowledgeable children with positive product evaluations and low nutritional knowledge choosing snacks from the advertised product category . Obese children were more likely to belong to a cluster of less knowledgeable and hedonism-oriented children . Conclusions : The problem of consumption of less healthy foods is complex and multiple factors need to be considered by health practitioners , social marketers and parents to address the issue of childhood obesity . Nutritional knowledge alone is not sufficient to ensure children make healthier food choices and emphasis should also be placed on persuasion knowledge education , targeting of peer norms , self-efficacy and stricter regulation of advertising aim ed at children The global epidemic of obesity and physical inactivity may have detrimental implication s for young people ’s  cognitive function and academic achievement . This prospect i ve study investigated whether childhood motor function predicts later academic achievement via physical activity , fitness , and obesity . The study sample included 8,061 children from the Northern Finl and Birth Cohort 1986 , which contains data about parent-reported motor function at age 8 y and self-reported physical activity , predicted cardiorespiratory fitness ( cycle ergometer test ) , obesity ( body weight and height ) , and academic achievement ( grade s ) at age 16 y.  Structural equation models with unst and ardized ( B ) and st and ardized ( β ) coefficients were used to test whether , and to what extent , physical activity , cardiorespiratory fitness , and obesity at age 16 mediated the association between childhood motor function and adolescents ’ academic achievement . Physical activity was associated with a higher grade -point average , and obesity was associated with a lower grade -point average in adolescence . Furthermore , compromised motor function in childhood had a negative indirect effect on adolescents ’ academic achievement via physical inactivity ( B = –0.023 , 95 % confidence interval = –0.031 , –0.015 ) and obesity ( B = –0.025 , 95 % confidence interval = –0.039 , –0.011 ) , but not via cardiorespiratory fitness . These results suggest that physical activity and obesity may mediate the association between childhood motor function and adolescents ’ academic achievement . Compromised motor function in childhood may represent an important factor driving the effects of obesity and physical inactivity on academic underachievement Background Obesity has become a global public health problem , which also affects children . It has been proposed that the educational interventions during childhood could be a key strategy in the prevention of obesity . Objective To evaluate the efficacy of an intervention on food habits and physical activity in school children . Methods A 2-year cluster-r and omised prospect i ve study with two parallel arms was used to evaluate an intervention programme in children in their first year of primary schooling ( 5–6 years of age ) in schools in the city of Granollers . The intervention consisted of the promotion of healthy eating habits and physical activity by means of the educational methodology Investigation , Vision , Action and Change ( IVAC ) . At the beginning and at the end of the study ( 2006 and 2008 ) the weight and height of each child was measured in situ , while the families were given a self-report physical activity question naire and the Krece Plus quick test . Results Two years after the beginning of the study , the body mass index of the children in the control group was 0.89 kg/m2 higher than that of the intervention schools . The intervention reduced by 62 % the prevalence of overweight children . Similarly , the proportion of children that ate a second piece of fruit and took part in an after-school physical activity increased in the intervention group . In the control group , the weekly consumption of fish was reduced . Conclusions The educational intervention in healthy eating habits and physical activity in the school could contribute to lessen the current increase in child obesity BACKGROUND / OBJECTIVES Aside from the health consequences , observational studies indicate that being overweight may also negatively affect cognitive function . However , existing evidence has to a large extent not controlled for the possible confounding effect of having different lifestyles . Therefore , the objective was to examine the independent associations between weight status and lifestyle indicators with cognitive performance in 8 - 11year old Danish children . SUBJECTS/ METHODS The analyses included 828 children ( measured in 2011 - 2012 ) each having one to three measurement occasions separated by approximately 100days .  Dietary intake , physical activity , sedentary time , and sleep duration were measured using dietary records and accelerometers . The Children 's Sleep Habits Question naire was used to access sleep problems and the And ersen test was carried out to estimate cardio-respiratory fitness ( CRF ) . Weight status ( underweight , normal weight , and overweight/obese ) was defined according to body mass index and cognitive performance was assessed using the d2-test of attention , a reading test , and a math test . A linear mixed model including a number of fixed and r and om effects was used to test associations between lifestyle indicators as well as BMI category and cognitive performance . RESULTS After adjustment for demographics , socioeconomics , and multiple lifestyle indicators , normal weight children had higher cognitive test scores than overweight/obese and underweight children of up to 89 % and 48 % of expected learning within one school year ( P<0.05 ) . Daily breakfast consumption , fewer sleep problems , higher CRF , less total physical activity , more sedentary time , and less light physical activity were associated with higher cognitive performance independently of each other in at least one of the three cognitive tests ( P<0.05 ) . CONCLUSIONS Normal weight children had higher cognitive performance compared to overweight/obese as well as underweight children , independent of multiple lifestyle indicators Background There is no data on diet- and activity-related behaviors associated with overweight and obesity among Pakistani school-aged children . The study aim ed to explore  dietary behaviors , physical activity and sedentary lifestyle  associated with overweight and obesity , and their socio-demographic correlates , among Pakistani primary school children . Methods A population -based cross-sectional study was conducted with a representative multistage r and om cluster sample of 1860 children aged five to twelve years in Lahore , Pakistan . Overweight ( > + 1 SD ) and obesity ( > + 2 SD ) were defined using the World Health Organization reference 2007 . Chi-square test was used as the test of trend . Linear regression was used to examine the predictive power of independent variables in relation to body mass index ( BMI ) . Logistic regression was used to quantify the independent predictors and adjusted odds ratios ( aOR ) with 95 % confidence intervals ( CI ) were obtained . Statistical significance was considered at P < 0.05 . Results Children skipping breakfast ( 8 % ) , eating fast food and snacks ≥ once a week ( 43 % ) and being involved in sedentary lifestyle > one hour a day ( 49 % ) were significantly more likely to be overweight and obese while those participating in physical activity > twice a week ( 53 % ) were significantly less likely to be overweight and obese ( all P < 0.01 ) . Skipping breakfast ( P < 0.001 ) , eating fast food and snacks ( P = 0.001 ) and sedentary lifestyle ( P < 0.001 ) showed an independent positive association with BMI while physical activity showed an independent inverse association ( P = 0.001 ) . Skipping breakfast ( aOR 1.82 , 95 % CI 1.22 - 2.71 ) , eating fast food and snacks ≥ once a week ( OR 1.41 , 95 % CI 1.07 - 1.86 ) , physical activity > twice a week ( aOR 0.49 , 95 % CI 0.34 - 0.70 ) and sedentary lifestyle > one hour a day ( aOR 1.56 , 95 % CI 1.19 - 2.03 ) were independent predictors of being overweight . Skipping breakfast had independent inverse association with physical activity ( aOR 0.63 , 95 % CI 0.45 - 0.89 ) and eating fast food and snacks had independent positive association with sedentary lifestyle ( aOR 1.79 , 95 % CI 1.49 - 2.16 ) . Female gender was independently associated with skipping breakfast ( aOR 1.50 , 95 % CI 1.04 - 2.16 ) . Male gender ( aOR 1.64 , 95 % CI 1.33 - 2.02 ) , urban area with high SES ( aOR 5.09 , 95 % CI 3.02 - 8.60 ) and higher parental education ( aOR 1.74 , 95 % CI 1.12 - 2.68 ) were significant independent predictors of eating fast food and snacks ≥ once a week . Living in the rural area was independently associated ( aOR 2.51 , 95 % CI 1.71 - 3.68 ) with physical activity > twice a week . Male gender ( aOR 1.60 , 95 % CI 1.31 - 1.95 ) , urban area with low SES ( aOR 1.46 , 95 % CI 1.02 - 2.09 ) , high-income neighborhoods ( aOR 1.52 , 95 % CI 1.02 - 2.25 ) , higher parental education ( aOR 1.55 , 95 % CI 1.03 - 2.34 ) and fewer siblings ( aOR 1.38 , 95 % CI 1.10 - 1.73 ) were independent predictors of sedentary lifestyle > one hour a day . Conclusions Dietary behaviors , physical activity and sedentary lifestyle are independent predictors of overweight  and higher BMI among Pakistani primary school children , and are significantly affected by the child 's socio-demographic characteristics . These findings support the urgent need to develop a National strategy for diet and physical activity and to implement culturally relevant behavioral interventions in the re source -poor developing country setting The aim of this study was to examine modifiable biological , psychological , behavioral and social-environmental correlates of physical activity among 1129 Norwegian 11-year-old children within a cross-sectional sample from the HEalth In Adolescents study .  Physical activity was assessed by accelerometer , and weight and height were measured objective ly . Age- and gender-specific cut-off points proposed by the International Obesity Task Force were used to define body mass index . Social-environmental variables were self-reported by question naire . Hierarchical regression ( linear mixed models ) revealed that normal weight children scored higher on percentage daily moderate-to-vigorous physical activity [ % daily moderate to vigorous physical activity ( MVPA ) ] than overweight/obese children ( P<0.001 ) . Self-efficacy ( P<0.01 ) and perceived social support from friends ( P<0.01 ) were positively associated with children 's % daily MVPA , and a negative association was found for computer/game-use on weekends ( P<0.01 ) . A moderator effect of weight category ( normal vs overweight/obese ) in the relationship between computer/game-use on weekends and % daily MVPA was detected ( P<0.05 ) , reflecting that higher computer/game-use on weekends was associated with lower % MVPA among the overweight/obese , but not among the normal weight . Modifiable correlates from multiple domains accounted for 14 % of the variance in % daily MVPA . Prospect i ve and intervention studies are needed to examine whether these factors act as mediators for physical activity change in pre-adolescent children The study examined the association of nutritional status , obesity and physical activity ( PA ) with  health-related quality of life ( HRQL ) in the elderly , and whether this relationship persists after controlling for confounders attributable to comorbidities , functional status and cognitive function . A total of 300 community-dwelling persons ( 177 women and 123 men ) between 66 and 79 years of age were r and omly chosen from all inhabitants of one district of the city of Lodz ( Pol and ) .  HRQL was assessed with the  Euroqol 5D  question naire . PA  was assessed by two question naires : the Seven Day Recall PA Question naire and the Stanford Usual Activity Question naire .  Comorbidities , nutritional state ( Mini Nutritional Assessment question naire – MNA ) , physical disability , cognitive function and psychological state were also assessed . In bivariate relationships body mass index ( BMI ) , waist-to-hip ratio ( WHR ) and the percentage of body fat were negatively related to several HRQL scores both in women and men . Similarly , many HRQL scores were positively related to PA indices in both genders . In multivariate relationships , after adjustments for age , gender , smoking status , number of medications taken , comorbidities and geriatric physical and cognitive function , BMI predicted lower mobility while the percentage of body fat independently contributed to more frequent pain/discomfort and anxiety/depression problems . An adequate MNA added to a higher usual activity score , while a higher Stanford Moderate PA Index predicted better overall perceived health state . These results indicate that excess body fatness and sedentary lifestyle have , together with several functional and medical comorbidities , an independent contribution to inferior HRQL in communitydwelling older subjects . ZusammenfassungDie Untersuchung prüfte den Einfluss des Ernährungszust and es , des Übergewichts und der Bewegungsaktivität auf Gesundheit und Lebensqualität ( HRQL ) bei älteren Personen , und ob dieser Zusammenhang weiter besteht , wenn die Störungen eliminiert werden , die mit dem begleitend auftretenden Krankheiten , dem funktionellen Zust and und der Erkenntnisfunktionen verbunden sind . An der Untersuchung nahmen 300 durch Los ausgewählte ältere ( 177 weibliche und 123 männliche ) zu Hause lebende Einwohner der Stadt Lodz i m Alter von 66 bis 79 teil . Gesundheit und Lebensqualität wurden mittels Euroqol 5DFragebogen beurteilt . Die Bewegungsaktivität wurde aufgrund zweier Fragebögen bewertet : Dem siebentägigen Fragebogen über die Bewegungsaktivität ( SDPAR ) und dem Fragebogen über die gewöhnlichen Tätigkeiten ( Stanford Usual Activity Question naire ) . Der Ernährungszust and wurde gemäß der MNA-Skala ( Mini Nutritional Assessment ) eingeschätzt . Der Beurteilung unterlagen ebenfalls : begleitende Auftreten von Krankheiten , Behinderungen , die funktionelle Leistungsfähigkeit und der psychische Zust and der Gefragten . In der einfaktoriellen Analyse der Varianten ANOVA , BMI , waren die Kennziffer des Umfangs der Taille und Hüften ( WHR ) , und der prozentuale Gehalt an Fettgewebe entsprechend reziprok zu manchen Ergebnissen der Lebensqualität sowohl bei den Frauen als auch bei den Männern . Eine ähnlich große Zahl von Ergebnissen dieser Lebensqualität wies eine proportionale ( positive ) Abhängigkeit von den Kennzahlen der physischen Aktivität für beide Geschlechter aus . In der multifaktoriellen Analyse , unter Berücksichtigung von Alter , Geschlecht , Rauchen , der Menge von eingenommenen Arzneimitteln , sowie der psychischen und körperlichen Aktivität , beeinträchtigte der BMI die Mobilität ( Beweglichkeit ) . Der prozentuelle Gehalt des Fettgewebes dagegen beeinflusste ein öfteres Schmerzempfinden/Discomfort bzw . Unruhe/Depression . Die entsprechende Beurteilung des Ernährungszust and es MNA verursachte ein höheres Aktivitätsergebnis als gewöhnlich , wobei der höhere ‘ Stanfort Moderater PA-Koeffizient ’ den besseren allgemeinen Gesundheitszust and bestimmte . Diese Ergebnisse bedeuten , dass das Übergewicht und die sitzende Lebensweise samt funktionell und medizinisch begleitenden Auftreten von Krankheiten einen unabhängigen Einfluss auf die Gesundheit und Lebensqualität der zu Hause lebenden älteren Personen haben Background The prevalence of childhood obesity has increased rapidly during the last three decades in the Netherl and s. It is assumed that mainly environmental factors have contributed to this trend . Parental overweight and low social economic status are risk factors for childhood obesity . Childhood obesity affects self-esteem and has negative consequences on cognitive and social development . Obese children tend to become obese adults , which increases the risk for developing cardiovascular complications , type 2 diabetes mellitus , and psychosocial problems . Additionally , the secretion of several gastrointestinal hormones , responsible for appetite and food intake , is impaired in obese subjects . Weight reduction through lifestyle changes in order to change health risks is , until now , suggested as the preferred treatment for childhood obesity . The objective of this study is the effect evaluation of a family-based cognitive behavioral multidisciplinary lifestyle treatment . The intervention aims to establish long-term weight reduction and stabilization , reduction of obesity-related health consequences and improvement of self-image by change of lifestyle and learning cognitive behavioral techniques . Study design / Methods In this r and omized clinical trial newly presented children with obesity ( 8 - 17 years old ) are divided , by r and omization , in an intervention and  control  group , both consisting of 40 obese children . The intervention is carried out in groups of 8 - 11 children , and consists of respectively 7 and 5 separate group meetings for the children and their parents and 1 joint group meeting of 2 ½ hours . Main topics are education on nutrition , self-control techniques , social skills , physical activity and improvement of self-esteem . The control group is given advice on physical activity and nutrition . For normal data comparison , data were collected of 40 normal-weight children , 8 - 17 years old . Discussion Because of the increasing prevalence of childhood obesity and the impact on the individual as well as on society , prevention and treatment of obesity in children is of great importance . For evaluation of short- and long-term effects of the treatment , measurements are taken before and after 3 months of treatment , and after 12 and 24 months follow-up . During these visits clinical and biochemical data are determined , cardiovascular fitness tests are performed and quality of life question naires are completed . Trial registration International St and ard R and omised Controlled Trial Number Register IS RCT OBJECTIVE To investigate the emergence of the inverse socioeconomic gradient in body mass index ( BMI ) in the first 6 years of life . Furthermore , associations of socioeconomic position ( SEP ) with BMI and total fat mass ( % ) were assessed at age 6 , and potential mediating factors in the pathway between SEP and children 's body composition were investigated . METHODS Nearly 3,656 Dutch children participating in a prospect i ve cohort study in Rotterdam , the Netherl and s , were included from 2002 to 2006 .  Maternal educational level and net household income were used as indicators of SEP .  BMI and fat mass were both outcome measures . Associations and mediation analyses were investigated using linear mixed models and linear regression analyses . RESULTS The lowest SEP groups showed a larger increase in BMI over time as compared to the highest SEP groups ( P < 0.001 ) , which result ed in the emergence of the inverse SEP gradient around 3 - 4.5 years of age . In 6-year-old children , both BMI and total fat mass were significantly higher for children of low educated mothers ( difference in BMI SDS : 0.24 ; 95 % CI 0.15 , 0.33 ; and in total fat mass ( % ) : 2.68 ; 95 % CI 2.19 , 3.17 ) , which was also shown for children with a low household income . This was mainly explained by parental BMI and prenatal smoking . CONCLUSIONS The inverse socioeconomic gradient in obesity emerges during the preschool period , and widens with increasing age . A public health strategy aim ed at tackling the development of inequalities in obesity in early childhood needs to start before birth and should include the prevention of prenatal smoking and obesity of parents This study explores the potential relationship between a series of cognitive abilities and  testosterone , dehydroepi and rosterone ( DHEA )  , and  rostenedione  , and body mass index ( BMI ) measurements in 5-year-old children . 60 boys and 69 girls were administered a test ( K-BIT ) which provided measurements of fluid intelligence ( Matrices subtest ) , crystallized intelligence ( Vocabulary subtest ) , and IQ composite ( the combination of the two subtests ) ; a sub- sample of 48 boys and 61 girls was also subjected to diverse tests related to theory of mind ( affective labeling , appearance-reality distinction , display rules , and false belief ) .  Testosterone , DHEA , and and rostenedione levels were measured using an enzyme immunoassay technique in saliva sample s. An analysis of variance failed to reveal any significant differences between boys and girls in any of the cognitive abilities assessed . The correlation analysis revealed a positive relationship between fluid intelligence and testosterone levels in boys , a negative relationship between crystallized intelligence and and rostenedione levels in girls , and between affective labeling and and rostenedione levels in boys . A multiple regression analysis indicated that and rostenedione and BMI were the best predictors for some of the cognitive abilities assessed OBJECTIVE To explore the contribution of biologic risk factors versus socio-demographic and environmental risk factors in cognitive development of children with birth weight less than 2000 g , at the age of 12 years . DESIGN Prospect i ve cohort study . SETTING Infants discharged from a NICU of a referral hospital , with birth weight less than 2000 g between 1987 - 89 and followed up in the High Risk Clinic . METHODS The children were assessed at the age of 12 years , with the Weschler 's Intelligence Scale for IQ and by Wide Range Achievement Test for mathematics skills . Mother 's education , father 's education , socio-economic status , family structure , spaciousness of the house , the locality in which the child lived and the type of school the child attended , were all recorded . A stimulation score was determined at 6 and 12 months and 3 years .  Family environment score was used at 12 years . RESULTS The cohort consisted of 180 children , with 90 controls . The mean IQ of the study group was 89.5 + - 16.9 , which was significantly lower than that of controls ( 97.2 + - 14.1 ) ( P < 0.05 ) . The mathematical skills of the study group were significantly poorer ( P < 0.05 ) than that of controls . A multiple linear regression analysis was done using IQ as the dependent variable and all risk factors at birth , stimulation scores and socio-environmental factors as independent variables . Mothers education was the most important factor contributing to the total IQ , a variance of 25.2 % of the total variance 44.2 PERCENT . Fathers education emerged as an important factor for mathematics skills . School was the next important factor for IQ as well as academics . Controlling for all other background factors , birth weight was the only biologic factor of significance , and this had a very small contribution . CONCLUSION  Parental education  and the type of school attended by the child were the most important factors influencing cognitive development . The only biologic factor of importance was birth weight , but this too had a very small contribution abstract Objectives : To determine whether perinatal nutrition influences cognitive function at 7 1/2 - 8 years in children born preterm . Design : R and omised , blinded nutritional intervention trial . Blinded follow up at 7 1/2 - 8 years . Setting : Intervention phase in two neonatal units ; follow up in a clinic or school setting . Subjects : 424 preterm infants who weighed under 1850 g at birth ; 360 of those who survived were tested at 7 1/2 - 8 years . Interventions : St and ard infant formula versus nutrient enriched preterm formula r and omly assigned as sole diet ( trial A ) or supplements to maternal milk ( trial B ) fed for a mean of 1 month . Main outcome measures : Intelligence quotient ( IQ ) at 7 1/2 - 8 years with abbreviated Weschler intelligence scale for children ( revised ) . Results : There was a major sex difference in the impact of diet . At 7 1/2 - 8 years boys previously fed st and ard versus preterm formula as sole diet had a 12.2 point disadvantage ( 95 % confidence interval 3.7 to 20.6 ; P<0.01 ) in verbal IQ . In those with highest intakes of trial diets corresponding figures were 9.5 point disadvantage and 14.4 point disadvantage in overall IQ ( 1.2 to 17.7 ; P<0.05 ) and verbal IQ ( 5.7 to 23.2 ; P<0.01 ) . Consequently , more infants fed term formula had low verbal IQ ( < 85 ) : 31 % versus 14 % for both sexes ( P=0.02 ) and 47 % versus 13 % in boys P=0.009 ) . There was a higher incidence of cerebral palsy in those fed term formula ; exclusion of such children did not alter the findings . Conclusions : Preterm infants are vulnerable to suboptimal early nutrition in terms of their cognitive performance — notably , language based skills — at 7 1/2 - 8 years , when cognitive scores are highly predictive of adult ones . Our data on cerebral palsy generate a new hypothesis that suboptimal nutritional management during a critical or plastic early period of rapid brain growth could impair functional compensation in those sustaining an earlier brain insult . Cognitive function , notably in males , may be permanently impaired by suboptimal neonatal nutrition OBJECTIVE To assess the intelligence , visuo-motor perception , motor competence and school performance of children with birth weight less than 2000 grams , at the age of 12 years . DESIGN Prospect i ve cohort study . SETTING Infants discharged from a Neonatal Special Care Unit of a referral hospital with birth weight less than 2000 g between 1987 - 89 and followed up in the High Risk Clinic . METHODS The children were assessed by the  Weschler 's Intelligence Scale , Bender Gestalt test for visuo-motor perception , Wide Range Achievement Test for specific learning disability , Draw-a-Person screening test for emotional problems and Movement Assessment Battery for motor competence . Academic achievement was also scrutinised . RESULTS One hundred and eighty children weighing less than 2000 grams at birth and ninety control children were assessed . The mean IQ of the study group was normal ( 89.5 + /- 16.9 ) , though significantly lower than that of controls ( 97.2 + /- 14.1 ; p<0.05 ) . Pre term SGA children had the lowest mean IQ ( 85.4 + /- 17.7 ) . In the 78 VLBW children , there were 12 ( 15.4 % ) mentally retarded children as compared to only 3 ( 3.3 % ) amongst controls ( p<0.001 ) . There were only 3 ( 3.8 % ) ' bright ' children among the VLBW group , as compared to 20 ( 22.2 % ) in the control group ( p<0.001 ) . Visuo-motor perception and motor competence of the study group was poor , and they had writing and mathematics learning disability , especially the preterm SGA and VLBW group . Academic achievement was poor and the incidence of borderline intelligence was 24.4 % , which has increased from 13.4 % at 6 years . CONCLUSIONS The intelligence and academic performance of the children weighing less than 2000 grams is significantly lower than that of controls , though within normal limits . They also have poor visuo-motor perception , motor incompetence , reading and mathematics learning disability . The preterm SGA and VLBW children had the poorest cognitive abilities
The authors even suggested in this case increasing educational levels as a means of reducing obesity .
Indeed , we have recently reported results from two experimental studies showing that mental work up-regulates appetite-stimulating hormones and promotes overconsumption of food ( 3,4 ) .
Furthermore , a careful examination of our data revealed that when the subjects were categorized on the basis of the mental workload intensity , those for whom the intensity of the mental effort was greater significantly increased their spontaneous food intake as compared with those characterized by a less strenuous cognitive effort .
In other words , the harder we think the more we eat .
This hyperphagic effect of intense thinking was also accompanied by more plasma glucose instabilities ( 5 ) .
The fluctuations in plasma glucose levels that were observed are in agreement with the literature showing that a period of intense cognitive processing leads to a measurable decrease in levels of blood glucose ( 6 ) , a fall that has also been associated with feeling less energetic ( 7 ) .
Accordingly , food intake might be perceived as a strategy for allowing the individual to recover optimal body functioning .
These observations are also relevant for students having hard times to learn at school and for whom study ing is arduous and mentally challenging .
On the basis of our observations , we find it realistic to postulate that those susceptible to commit more cognitive effort to take in charge st and ard mental tasks are more likely to over-eat and gain weight compared with those for whom the accomplishment of mental tasks at the same level of performance is elementary or more natural .
Along the same lines , it would not be surprising to find a higher dropout rate for those ‘ mentally stressed ’ students .
In a system where academic performance continues to rank as high priority in public schools , it seems obvious that some students are genetically more gifted and likely to perform at a higher level ( 8) .
As previously shown , better cognitive abilities are predictive of more important life achievements such as earning a doctorate , securing a patent , or publishing a novel or major literary work ( 9 ) .
It may be somewhat paradoxical that the amount of knowledge-based work is more important in the higher socioeconomic groups whereas population data show a higher prevalence of obesity for the socioeconomically disadvantaged .
Thus , individuals highly involved in mental work are not all likely to over-eat and other healthy behaviours such as regular physical activity may counterbalance the net impact on energy balance .
As mentioned in the paper by Yu and co-workers ( 1 ) , educational attainment seems to be an important mediator of this relationship .
In an early view issue of this journal , Yu and co-workers ( 1 ) published a systematic review and meta- analysis about the mutual relationship between obesity and intelligence quotient ( IQ ) .
The authors observed that a lower IQ score in childhood was associated with obesity in later adulthood .
Although it is not possible to definitively rule out reverse causation in the IQ – obesity relationship , two main mechanisms have been put forward by the authors that could explain why a low IQ has been found to be a predictor of obesity .
First , higher intelligence may reduce the risk of obesity by promoting more healthful behaviours .
For example , data from a cohort study showed that children with higher mental ability scores reported significantly more frequent consumption of fruit and vegetables and more high-intensity physical activity participation in adulthood ( 2 ) .
Second , higher childhood IQ may predict favourable socioeconomic positions later in life .
With the advent of computers and new technologies , the pendulum has swung far in the direction of excessive mental activities , as opposed to excessive physical activities .
A careful examination of computer-related activities reveals that they represent a particular type of sedentary activities ; they are stressful and biologically dem and ing for the body and deserve to be counterbalanced by an adequate physical activity regimen ( 10 ) .