Neuropeptide Y (NPY) is a powerful regulator of anxious states, including social anxiety, but evidence from human genetic studies is limited. Associations of common gene variants with behaviour have been described as subject to birth cohort effects, especially if the behaviour is socially motivated. This study aimed to examine the association of NPY rs16147 and rs5574 with personality traits in highly representative samples of two birth cohorts of young adults, the samples having been formed during a period of rapid societal transition.

Both birth cohorts (original n = 1238) of the Estonian Children Personality Behaviour and Health Study (ECPBHS) self-reported personality traits of the five-factor model at 25 years of age.

A significant interaction effect of the NPY rs16147 and rs5574 and birth cohort on Agreeableness was found. The T/T genotype of NPY rs16147 resulted in low Agreeableness in the older cohort (born 1983) and in high Agreeableness in the younger cohort (born 1989). The C/C genotype of NPY rs5574 was associated with higher Agreeableness in the younger but not in the older cohort. In the NPY rs16147 T/T homozygotes, the deviations from average in Agreeableness within the birth cohort were dependent on the serotonin transporter promoter polymorphism.

The association between the NPY gene variants and a personality domain reflecting social desirability is subject to change qualitatively in times of rapid societal changes, serving as an example of the relationship between the plasticity genes and environment. The underlying mechanism may involve the development of the serotonergic system.

Cholecystokinin is a neuropeptide with a role in the neurobiology of adaptive behaviour that is implicated in anxiety disorders, while the underlying mechanisms currently remain insufficiently explained. The rs2941026 variation in the cholecystokinin B receptor gene has previously been associated with trait anxiety. Our aim was to investigate associations between the CCKB receptor gene polymorphism rs2941026 with anxiety, personality, depressiveness and suicidality in a longitudinal study of late adolescence and early adulthood.

We used reports on trait and state anxiety, depressiveness and suicidal thoughts, as well as Affective Neuroscience Personality Scales, from the two birth cohorts of the Estonian Children Personality, Behaviour and Health Study. We measured associations between the CCKBR gene rs2941026 and anxiety-related phenotypes both longitudinally and cross-sectionally at ages 15, 18, 25 and 33.

Homozygosity for both alleles of the CCKBR rs2941026 was associated with higher trait and state anxiety in the longitudinal analysis. Cross-sectional comparisons were statistically significant at ages 18 and 25 for trait anxiety and at ages 25 and 33 for state anxiety. Higher depressiveness and suicidal thoughts were associated with the A/A genotype at age 18. Additionally, homozygosity for the A-allele was related to higher FEAR and SADNESS in the Affective Neuroscience Personality Scales. The genotype effects were more apparent in females, who displayed higher levels of negative affect overall.

CCKBR genotype is persistently associated with negative affect in adolescence and young adulthood. The association of the CCKBR rs2941026 genotype with anxiety-related phenotypes is more pronounced in females.

The knowledge about the association of physical activity (PA) and sedentary behaviours (SB) with the most considered healthy dairy products consumption, as milk and yogurt, in childhood is scared.

To assess the longitudinal relationship between specific lifestyle behaviours (PA and SB) and combined dairy consumption (milk + yogurt) in a sample of European children.

Two measurements, with 2 years’ interval (T0 and T1), were conducted in 1 688 (50.8% boys) childrenfrom the IDEFICS study. Dietary information was parental-registered by a 24-hour dietary recall. At both time points, sedentary behaviour and objective estimation of PA was obtained by accelerometers. Different groups were defined according to the international children's PA and SB behaviours recommendations over time. The cut-offs for the SB and PA recommendations were established on 2hour/day of SB and 2 hour/day of moderate to vigorous PA. Multilevel ordinal logistic regression models were used to assess the group's association with the combined dairy consumption (milk + yogurt), adjusted for potential confounders (sex, body mass index zscore, intervention versus control region, parental education level, dietary quality index, energy intake and the consumption by each dairy group at T0).

Nine groups of meeting or not both recommendations (SB and PA) were obtained. Those children who meeting both lifestyle recommendations at both measurement points, had higher probability to consume more milk and yogurt (p < 0.05), in comparison to the rest of combinations.Those children who did not meet any recommendations at both time points were less likely to consume milk + yogurt (OR: 0.47, 95%CI:0.26–0.83) than those who met both recommendations at both time points. Those children which improved one behaviours (PA or SB) between both measurement point were associated with low consumption of milk + yogurt (OR:0.41, 95%CI 0.22;0.74; OR:0.40, 95%CI 0.22,0.72), compared with those who meet both lifestyle recommendations at both periods (T0 and T1). Also, those which improved both behaviours (PA and SB) were less likely to consume milk + yogurt (OR:0.34, 95%CI 0.15–0.80) than those who were physically active and low sedentary at both time points.

These results suggest that European children with a healthy lifestyle regarding PA and SB over time, had the highest milk and yogurt consumption in comparison with other children.

Out of the baseline sample of the IDEFICS Study, 2913 children aged 2–9 years were included in this study. Inclusion criteria was having available data of waist circumference (WC), diastolic and systolic blood pressure (DBP, SBP), high density lipoprotein (HDL) cholesterol, triglycerides (TG), glucose and insulin, to calculate the homeostasis model assessment index (HOMA); and hs-CRP as a marker of inflammation, at baseline (T0) and two years later (T1). hs-CRP was categorized into two categories as some children had lower concentration than the detection limit of 0.02mg/dL. Student t-test and logistic regression were used to assess these associations. Logistic regression was adjusted by age, sex, body mass index (BMI), socioeconomic level and country.

Differences of mean values of the components of the MetS and the two categories of hs-CRP were observed between both time points. Mean values of SBP, DBP, WC, TG and HOMA were significantly higher in children with a higher category of hsCRP (p < 0.005). In addition, MetS score was significantly higher in those with a higher category of hs-CRP (p < 0.001) at both measurement points, T0 and T1. Finally, logistic regression between components of MetS and categories of hs-CRP, at both time points, showed significant associations (p < 0.001) for WC (OR = 1.06 at T0 and OR = 1.04 at T1) and HDL (OR = 0.98 at T0 and OR = 0.98 at T1) and the MetS score (OR = 1.07) score at T1.

The association between MetS and inflammation is already present in children. Out of the components of the MetS, WC and HDL were the ones more associated with an inflammatory state at two times points. Also the MetS score, but only at the follow-up, was associated with the hs-CRP. Therefore, in order to prevent the inflammatory state in childhood, efforts to improve the metabolic profile, specially WC and HDL, need to be made.

Severe behavioural issues such as impulsive action and suicide have since long been associated with low levels of cholesterol. While it is known that cholesterol plays a role in neural development and hence low levels of serum lipids could have long-term effects on behaviour, no longitudinal studies showed the association of serum lipids levels with impulsivity. We aimed to examine the prognostic properties of serum lipid levels during childhood and adolescence on measures of impulsivity during early adulthood in a representative birth cohort sample.

We have investigated whether serum lipid levels measured at 9, 15, 18 and 25 years of age have an association with impulsivity in 25 years old young adults. This analysis was based on data of the birth cohort representative samples of the Estonian Children Personality Behaviour and Health Study (original n = 1238). Impulsivity was self-reported with the Adaptive and Maladaptive Impulsivity Scale.

Total and low-density lipoprotein (LDL) cholesterol measured in boys aged 9, 15 and 18 years predicted disinhibition and thoughtlessness in 25-year-old young adults. High scores of disinhibition were associated with low total and LDL cholesterol levels in males but, while less consistently, with high total and LDL cholesterol levels in females. Cross-sectional analysis did not result in systematic outcomes.

Serum lipid levels could have an impact on the development of Maladaptive Impulsivity starting from an early age. This effect of cholesterol continues throughout adolescence into young adulthood.

Consumption of fruits and vegetables (F&V) among adolescents falls below recommendations in many Western countries. The impact of social and emotional aspects of family life on adolescent dietary behaviour may contribute to this, yet remains under-investigated. The present study examines the association between adolescents’ perceptions of emotional home atmosphere (EHA) and their F&V consumption frequency.

An FFQ was used to assess F&V consumption frequency. EHA was assessed by an eight-item measure with three subscales: perceived home warmth, strictness and relational tension. EHA subscales were used as binary variables: a score equal to or above the median value was considered as a higher perception, while a score below the median was considered as a lower perception of the EHA in question. Country differences in meeting the European 5-a-day recommendations were described. Further, the association between EHA and F&V consumption frequency was investigated using multiple linear regression.

Regional examination centres in eight European countries.

Adolescents (n 3196) aged 12–18 years.

The mean F&V consumption frequency was 3·27 (sd 2·84) times/d. Only 16·1 % of boys and 18 % of girls in our study sample met the recommendation of five F&V daily. After controlling for age, sex, education level of the parents and country of origin, perceived home warmth was associated with a 16 (95 % CI 9, 22) % higher F&V consumption frequency (P < 0·001).

F&V consumption frequency was suboptimal in the survey areas. Interventions targeting perceived warmth as a component of EHA could potentially have a positive effect on adolescents’ dietary behaviour.

The present study investigated the association between sugar and fat intake in childhood in relation to alcohol use in adolescence. We hypothesized that early exposure to diets high in fat and sugar may affect ingestive behaviours later in life, including alcohol use.

Children from the European IDEFICS/I.Family cohort study were examined at ages 5–9 years and followed up at ages 11–16 years. FFQ were completed by parents on behalf of children, and later by adolescents themselves. Complete data were available in 2263 participants. Children’s propensities to consume foods high in fat and sugar were calculated and dichotomized at median values. Adolescents’ use of alcohol was classified as at least weekly v. less frequent use. Log-binomial regression linked sugar and fat consumption in childhood to risk of alcohol use in adolescence, adjusted for relevant covariates.

Five per cent of adolescents reported weekly alcohol consumption. Children with high propensity to consume sugar and fat were at greater risk of later alcohol use, compared with children with low fat and low sugar propensity (relative risk=2·46; 95 % CI 1·47, 4·12), independent of age, sex and survey country. The association was not explained by parental income and education, strict parenting style or child's health-related quality of life and was only partly mediated by sustained consumption of sugar and fat into adolescence.

Frequent consumption of foods high in fat and sugar in childhood predicted regular use of alcohol in adolescence.

Physical activity (PA) levels and dietary habits are considered some of the most important factors associated with obesity. The present study aimed to examine the association between PA level and food and beverage consumption in European children (2–10 years old).

A sample of 7229 children (49·0 % girls) from eight European countries participating in the IDEFICS (Identification and prevention of Dietary and lifestyle induced health EFfects In Children and infantS) study was included. Moderate-to-vigorous PA (MVPA) was assessed objectively with accelerometers. FFQ was used to register dietary habits. ANCOVA and binary logistic regression were applied.

Boys who spent less time in MVPA reported lower consumption of vegetables, fruits, cereals, yoghurt, milk, bread, pasta, candies and sugar-sweetened beverages (SSB) than boys who spent more time in MVPA (P<0·05). Moreover, boys who spent less time in MVPA were more likely to consume fast foods and water than those in the highest MVPA tertile (P<0·05). Girls who spent less time in MVPA reported lower consumption frequencies of vegetables, pasta, bread, yoghurt, candies, jam/honey and SSB than girls in the highest MVPA tertile (P<0·05). Also, girls in the lowest MVPA tertile were more likely to consume fast foods and water than those with high levels of MVPA (P<0·05).

Food intake among European children varied with different levels of daily MVPA. Low time spent in MVPA was associated with lowest consumption of both high- and low-energy-dense foods and high fast-food consumption.

To estimate the prevalence of physical activity and sedentary behaviours in European children, and to evaluate the relationship between media availability in personal space and physical activity in relation to total screen time.

Data from the baseline IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) cross-sectional survey. Information on hours of television/digital video disk/video viewing and computer/games-console use (weekday and weekend days), media device availability in personal space, sports club membership, hours of active organized play and commuting (to and from school) were assessed via a self-reported parental questionnaire. Total screen time was defined as the sum of daily media use and subsequently dichotomized into meeting or not meeting the guidelines of the American Academy of Pediatrics.

Eight survey centres (Italy, Estonia, Cyprus, Belgium, Sweden, Germany, Hungary and Spain).

Children (n 15 330; 51 % males) aged 2–10 years.

Percentage of children engaged in total screen time for >2 h/d was higher on weekend days (52 % v. 20 % on weekdays) and in the older group (71 % in males; 57 % in females), varying by country. Children with a television set in their bedroom were more likely not to meet the screen time recommendations (OR = 1·54; 95 % CI 1·60, 1·74).

Approximately a third of the children failed to meet current screen time recommendations. Availability of a television set in personal space increased the risk of excess total screen time. This information could be used to identify potential targets for public health promotion actions of young population groups.

To analyse the association between family structure and adiposity in children.

Cross-sectional and longitudinal analysis of the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study cohort.

Primary schools and kindergartens.

Children (n 12 350; aged 7·9 (sd 1·8) years) for the cross-sectional analysis and children (n 5236; at baseline: normal weight, aged 5·9 (sd 1·8) years) for the longitudinal study underwent anthropometry. Family structure was analysed as (i) number and type of cohabiting adults and (ii) number of siblings.

In the cross-sectional analysis, after controlling for covariates, children living with grandparents had significantly higher BMI Z-score than those living with both parents (0·63; 95 % CI 0·33, 0·92 v. 0·19; 95 % CI 0·17, 0·22; P < 0·01); in addition, the higher the number of siblings, the lower the BMI Z-score (only child = 0·31; 95 % CI 0·24, 0·38; 1 sibling = 0·19; 95 % CI 0·16, 0·23; 2 siblings = 0·15; 95 % CI 0·09, 0·20; >2 siblings = 0·07, 95 % CI 0·04, 0·19; P < 0·001). Over the 2-year follow-up, differences in weight gain were observed across family-structure categories. Further, the risk of incidence of overweight/obesity was significantly lower the higher the number of siblings living in the household (v. only child: 1 sibling = 0·74, 95 % CI 0·57, 0·96; 2 siblings = 0·63, 95 % CI 0·45, 0·88; >2 siblings = 0·40, 95 % CI 0·21, 0·77), independently of confounders.

The study suggests that an independent association between family structure and childhood obesity exists.

Monoamine oxidase A (MAOA) gene promoter region includes a variable number of tandem repeat (VNTR) associated with antisocial behaviour in adverse environment. We have examined the effect of the MAOA-uVNTR on mental health and academic success by using a population representative sample and a longitudinal design.

The data of the older cohort (n = 593, aged 15 years at the original sampling) of the longitudinal Estonian Children Personality, Behaviour and Health Study (ECPBHS) were used. Follow-ups were conducted at ages 18 and 25 years. Aggressiveness, inattention and hyperactivity were reported by class teachers or, at older age, self-reported. Stressful life events, psychological environment in the family and interactions between family members were self-reported. Data of general mental abilities and education were obtained at the age of 25, and lifetime psychiatric disorder assessment was carried out with the Mini-International Neuropsychiatric Interview (MINI) interview.

MAOA-uVNTR genotype had no independent effect on aggressiveness, hyperactive and inattentive symptoms, and neither was there a genotype interaction with adverse life events. Interestingly, the proportion of male subjects with higher education by the age of 25 was significantly larger among those with MAOA low-activity alleles (χ2 = 7.13; p = 0.008). Logistic regression revealed that MAOA low-activity alleles, higher mental abilities, occurrence of anxiety disorders and absence of substance-use disorder were significant independent predictors for higher education in male subjects.

In a population representative sample of young subjects, the MAOA-uVNTR ‘risk genotype’ predicted better life outcomes as expressed in higher level of education.

To compare, specifically by age group, proxy-reported food group estimates obtained from the food frequency section of the Children's Eating Habits questionnaire (CEHQ-FFQ) against the estimates of two non-consecutive 24 h dietary recalls (24-HDR).

Estimates of food group intakes assessed via the forty-three-food-group CEHQ-FFQ were compared with those obtained by a computerized 24-HDR. Agreement on frequencies of intakes (equal to the number of portions per recall period) between the two instruments was examined using crude and de-attenuated Pearson's correlation coefficients, cross-classification analyses, weighted kappa statistics (κw) and Bland–Altman analysis.

Kindergartens/schools from eight European countries participating in the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) Study cross-sectional survey (2007–2008).

Children aged 2–9 years (n 2508, 50·4 % boys).

The CEHQ-FFQ provided higher intake estimates for most of the food groups than the 24-HDR. De-attenuated Pearson correlation coefficients ranged from 0·01 (sweetened fruit) to 0·48 (sweetened milk) in children aged 2–<6 years (mean = 0·25) and from 0·01 (milled cereal) to 0·44 (water) in children aged 6–9 years (mean = 0·23). An average of 32 % and 31 % of food group intakes were assigned to the same quartile in younger and older children, respectively, and classification into extreme opposite quartiles was ≤12 % for all food groups in both age groups. Mean κw was 0·20 for 2–<6-year-olds and 0·17 for 6–9-year-olds.

The strength of association estimates assessed by the CEHQ-FFQ and the 24-HDR varied by food group and by age group. Observed level of agreement and CEHQ-FFQ ability to rank children according to intakes of food groups were considered to be low.

To assess the association between exclusive breast-feeding and childhood overweight.

Cross-sectional data are from the baseline survey of the longitudinal cohort study IDEFICS. Exclusive rather than partial breast-feeding is the focus of the study due to the theoretical relationship between exclusive breast-feeding and development of dietary self-regulation. Children's measured heights and weights were used to calculate weight status, while waist-to-height ratio (WtHR) and skinfold measures were examined as alternative indicators of adiposity and fat patterning.

Examination centres in eight European countries (Italy, Estonia, Cyprus, Belgium, Sweden, Hungary, Germany and Spain).

The analysis included 14 726 children aged 2–9 years for whom early feeding practices were reported by parents in standardized questionnaires.

After controlling for education, income and other potential confounders, breast-feeding exclusively for 4–6 months was protective of overweight (including obesity) when compared with children never exclusively breast-fed (OR = 0·73; 95 % CI 0·63, 0·85) across all measures of overweight. Exclusively breast-feeding for 6 months offered slightly more protection than for 4 and 5 months combined (OR = 0·71; 95 % CI 0·58, 0·85). The associations could not be explained by socio-economic characteristics or maternal overweight.

This multi-country investigation indicated that exclusive breast-feeding for 4–6 months may confer protection against overweight in addition to other known benefits. There was no demonstrated benefit of exclusive breast-feeding for more than 6 months or combination feeding for any duration across all measures of overweight examined.