Krishna Vyncke

Stress, emotional eating behaviour and dietary patterns in children

Psychological stress has been suggested to change dietary pattern towards more unhealthy choices and as such to contribute to overweight. Emotional eating behaviour could be an underlying mediating mechanism. The interrelationship between stress, emotional eating behaviour and dietary patterns has only rarely been examined in young children. Nevertheless, research in children is pivotal as the foundations of dietary habits are established starting from childhood and may track into adulthood. In 437 children (5-12years) of the ChiBS study, stress was measured by questionnaires on stressful events, emotions (happy, angry, sad, anxious) and problems (emotional, peer, conduct and hyperactivity). Data were collected on childrens emotional eating behaviour and also on dietary patterns: frequency of fatty foods, sweet foods, snacks (fat and sweet), fruit and vegetables. Stressful events, negative emotions and problems were positively associated with emotional eating. Positive associations were observed between problems and both sweet and fatty foods consumption. Negative associations were observed between events and fruit and vegetables consumption. Overall, stress was associated with emotional eating and a more unhealthy dietary pattern and could thus contribute to the development of overweight, also in children. Nevertheless, emotional eating behaviour was not observed to mediate the stress-diet relation.

Intercorrelations between serum, salivary, and hair cortisol and child-reported estimates of stress in elementary school girls

To evaluate the impact of stress on childrens well-being, it is important to have valid and reliable stress assessment methods. Nevertheless, selection of an appropriate method for a particular research question may not be straightforward, as there is currently no consensus on a reference method to measure stress in children. This article examined to what extent childhood stress can be estimated accurately by stressor questionnaires (i.e., Coddington life events scale) and biological markers (serum, salivary, and hair cortisol) using the Triads (a triangulation) method in 272 elementary school girls. Salivary cortisol was shown to most accurately indicate true childhood stress for short periods in the past (i.e., last 3 months), whereas hair cortisol may be preferred above salivary measurements for periods more distant and thus for chronic stress assessment. However, applicability should be confirmed in larger and more heterogeneous populations.

Children’s Body composition and Stress – the ChiBS study: aims, design, methods, population and participation characteristics

BackgroundThe last decades, the prevalence of childhood obesity has increased. Apart from other lifestyle factors, the effect of chronic psychosocial stress on the development of obesity has been recognized. However, more research is needed into the influence of chronic stress on appetite regulation, energy balance and body composition, as well as on the interaction with physical activity/sedentary behavior, diet and sleep in children. In this regard, the ChiBS study (Children’s Body composition and Stress) was designed at the Ghent University. Within this paper, we describe the aims, design, methods, participation and population characteristics of the ChiBS study.MethodsThe influence of chronic stress on changes in body composition is investigated over a two-year follow-up period (February-June 2010, 2011 and 2012) in primary-school children between 6 and 12 years old in the city Aalter (Flanders, Belgium).Stress is measured by child- and parent-reported stress-questionnaires, as well as by objective stress biomarkers (serum, salivary and hair cortisol) and heart rate variability. Body composition is evaluated using basic anthropometric measurements and air displacement plethysmography. Additional information on socio-economic status, medical history, physical activity, dietary intake and sleep are obtained by questionnaires, and physical activity by accelerometers.ResultsThe participation percentage was 68.7% (N = 523/761), with 71.3% of the children willing to participate in the first follow-up survey. Drop-out proportions were highest for serum sampling (12.1%), salivary sampling (8.3%) and heart rate variability measurements (7.4%).DiscussionThe ChiBS project is unique in its setting: its standardized and longitudinal approach provides valuable data and new insights into the relationship between stress and changes in body composition in a large cohort of young children. In addition, this study allows an in-depth investigation of the validity of the different methods that were used to assess stress levels in children.

Blood pressure reference values for European non-overweight school children: the IDEFICS study.

Objectives:To provide oscillometric blood pressure (BP) reference values in European non-overweight school children.Design:Cross-sectional analysis from the IDEFICS study (www.ideficsstudy.eu) database.Methods:Standardised BP and anthropometric measures were obtained from children aged 2 to 10.9 years, participating in the 2007–2008 and 2009–2010 IDEFICS surveys. Age- and height-specific systolic and diastolic pressure percentiles were calculated by GAMLSS, separately for boys and girls, in both the entire population (n=16 937) and the non-overweight children only (n=13 547). The robustness of the models was tested by sensitivity analyses carried out in both population samples.Results:Percentiles of BP distribution in non-overweight children were provided by age and height strata, separately for boys and girls. Diastolic BP norms were slightly higher in girls than in boys for similar age and height, while systolic BP values tended to be higher in boys starting from age 5 years. Sensitivity analysis, comparing BP distributions obtained in all children with those of non-overweight children, showed that the inclusion of overweight/obese individuals shifted the references values upward, in particular systolic BP in girls at the extreme percentiles.Conclusions:The present analysis provides updated and timely information about reference values for BP in children aged 2 to <11 years that may be useful for monitoring and planning population strategies for disease prevention.

Determinants of vitamin D status in young children: results from the Belgian arm of the IDEFICS (Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants) Study

OBJECTIVE To describe the vitamin D status of Belgian children and examine the influence of non-nutritional determinants, in particular of anthropometric variables. DESIGN Cross-sectional data of Belgian participants of the EU 6th Framework Programme IDEFICS (Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants) Study. SETTING 25-Hydroxyvitamin D (25(OH)D) was measured using RIA. Vitamin D status was categorized as deficient (<25 nmol/l), insufficient (25-50 nmol/l), sufficient (50-75 nmol/l) and optimal (≥75 nmol/l). Anthropometric measurements included height, weight, waist and hip circumferences and triceps and subscapular skinfold thicknesses. SUBJECTS Children (n 357) aged 4-11 years. RESULTS Serum 25(OH)D ranged from 13·6 to 123·5 nmol/l (mean 47·2 (sd 14·6) nmol/l); with 5 % deficient, 53 % insufficient, 40 % sufficient and 2 % optimal. No significant differences were found by age and gender. Significant differences in 25(OH)D were observed for month of sampling (P < 0·001), number of hours playing outside per week (r = 0·140), weight (r = -0·121), triceps (r = -0·112) and subscapular (r = -0·119) skinfold thickness, sum of two skinfold thicknesses (r = -0·125) and waist circumference (r = -0·108). Linear regression analysis of 25(OH)D adjusted for age, month of sampling and hours playing outside per week suggested that (i) weight, (ii) BMI Z-score, (iii) waist circumference and (iv) triceps and subscapular skinfold thickness (as well as the sum of both) independently influenced 25(OH)D. CONCLUSIONS The majority of Belgian children had a suboptimal vitamin D status, with more than half having an insufficient status in winter and spring. Month of the year, weekly number of hours playing outside and body composition - both central and abdominal obesity - were identified as important determinants of vitamin D status in Belgian children.

FADS1 Genetic Variability Interacts with Dietary α-Linolenic Acid Intake to Affect Serum Non-HDL–Cholesterol Concentrations in European Adolescents

Two rate-limiting enzymes in PUFA biosynthesis, Δ5- and Δ6-desaturases, are encoded by the FADS1 and FADS2 genes, respectively. Genetic variants in the FADS1-FADS2 gene cluster are associated with changes in plasma concentrations of PUFA, HDL- and LDL-cholesterol, and TG. However, little is known about whether dietary PUFA intake modulates these associations, especially in adolescents. We assessed whether dietary linoleic acid (LA) or α-linolenic acid (ALA) modulate the association between the FADS1 rs174546 polymorphism and concentrations of PUFA, other lipids, and lipoproteins in adolescents. Dietary intakes of LA and ALA, FADS1 rs174546 genotypes, PUFA levels in serum phospholipids, and serum concentrations of TG, cholesterol, and lipoproteins were determined in 573 European adolescents from the HELENA study. The sample was stratified according to the median dietary LA (≤9.4 and >9.4 g/d) and ALA (≤1.4 and >1.4 g/d) intakes. The associations between FADS1 rs174546 and concentrations of PUFA, TG, cholesterol, and lipoproteins were not affected by dietary LA intake (all P-interaction > 0.05). Similarly, the association between the FADS1 rs174546 polymorphism and serum phospholipid concentrations of ALA or EPA was not modified by dietary ALA intake (all P-interaction > 0.05). In contrast, the rs174546 minor allele was associated with lower total cholesterol concentrations (P = 0.01 under the dominant model) and non-HDL-cholesterol concentrations (P = 0.02 under the dominant model) in the high-ALA-intake group but not in the low-ALA-intake group (P-interaction = 0.01). These results suggest that dietary ALA intake modulates the association between FADS1 rs174546 and serum total and non-HDL-cholesterol concentrations at a young age.

Does the FTO gene interact with the socioeconomic status on the obesity development among young European children? Results from the IDEFICS study

Background:Various twin studies revealed that the influence of genetic factors on psychological diseases or behaviour is more expressed in socioeconomically advantaged environments. Other studies predominantly show an inverse association between socioeconomic status (SES) and childhood obesity in Western developed countries. The aim of this study is to investigate whether the fat mass and obesity-associated (FTO) gene interacts with the SES on childhood obesity in a subsample (N=4406) of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) cohort.Methods:A structural equation model (SEM) is applied with the latent constructs obesity, dietary intakes, physical activity and fitness habits, and parental SES to estimate the main effects of the latter three variables and a FTO polymorphism on childhood obesity. Further, a multiple group SEM is used to explore whether an interaction effect exists between the single nucleotide polymorphism rs9939609 within the FTO gene and SES.Results:Significant main effects are shown for physical activity and fitness (standardised [betacrc ]s = −0.113), SES ([betacrc ]s = −0.057) and the FTO homozygous AA risk genotype ([betacrc ]s = −0.177). The explained variance of obesity is ~9%. According to the multiple group approach of SEM, we see an interaction between SES and FTO with respect to their effect on childhood obesity (Δχ2=7.3, df=2, P=0.03).Conclusion:Children carrying the protective FTO genotype TT seem to be more protected by a favourable social environment regarding the development of obesity than children carrying the AT or AA genotype.

Blood lipids among young children in Europe: results from the European IDEFICS study.

Background:Measurement of cholesterol and triglyceride (TG) fractions in blood has become standard practice in the early detection of atherosclerotic disease pathways. Considerable attention is given nowadays to the presence of these risk factors in children and to start preventive campaigns early in life. In this context, it is imperative to have valid comparative frameworks for interpretation of lipid levels. The aim of this study is to present sex- and age-specific reference values on blood lipid levels in European children aged 2.0–10.9 years.Methods:Fasting blood was obtained via either venipuncture or capillary sampling. In 13 579 European non-obese children (50.3% boys), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), TG and TC/HDL-C ratio levels were measured with a point-of-care analyser (Cholestech). Sex- and age-specific reference values were computed with the GAMLSS method with the statistical software R.Results:Reference curves and 1st, 3rd, 10th, 25th, 50th, 75th, 90th, 97th and 99th percentile values are presented. HDL-C showed a positive trend with age, from 2 years onwards, but was relatively stable above the age of 7. For LDL-C and TC, linear but small age-related trends were seen. The TC/HDL-C values showed a gradual negative trend from the age of 2 up to 6 and were relatively stable afterwards. For TG, no age trend was found (P=0.285). Boys had higher mean HDL-C values than girls (1.414 vs 1.368 mmol l−1), and lower TC, LDL-C, TC/HDL-C and TG values (3.981 vs 4.087 mmol l−1; 2.297 vs 2.435 mmol l−1; 2.84 vs 3.01mmol l−1;  and 0.509 vs 0.542 mmol l−1, respectively).Conclusions:These new and recent references could serve as a European orientation of blood lipid values in children in the context of standard medical practice and for the purpose of public health screening.

Reference values of whole-blood fatty acids by age and sex from European children aged 3-8 years

Objectives:To establish reference values for fatty acids (FA) especially for n-3 and n-6 long-chain polyunsaturated FAs (LC PUFA) in whole-blood samples from apparently healthy 3–8-year-old European children. The whole-blood FA composition was analysed and the age- and sex-specific distribution of FA was determined.Design and subjects:Blood samples for FA analysis were taken from 2661 children of the IDEFICS (identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study cohort. Children with obesity (n=454) and other diseases that are known to alter the FA composition (n=450) were excluded leaving 1653 participants in the reference population.Measurements:The FA composition of whole blood was analysed from blood drops by a rapid, validated gas chromatographic method.Results:Pearson correlation coefficients showed an age-dependent increase of C18:2n-6 and a decrease of C18:1n-9 in a subsample of normal weight boys and girls. Other significant correlations with age were weak and only seen either in boys or in girls, whereas most of the FA did not show any age dependence. For age-dependent n-3 and n-6 PUFA as well as for other FA that are correlated with age (16:0, C18:0 and C18:1n-9) percentiles analysed with the general additive model for location scale and shape are presented. A higher median in boys than in girls was observed for C20:3n-6, C20:4n-6 and C22:4n-6.Conclusions:Given the reported associations between FA status and health-related outcome, the provision of FA reference ranges may be useful for the interpretation of the FA status of children in epidemiological and clinical studies.

Comparison of different approaches to calculate nutrient intakes based upon 24-h recall data derived from a multicenter study in European adolescents

AbstractPurpose The European “Healthy Lifestyle in Europe by Nutrition in Adolescence” (HELENA) project evaluated two different approaches to harmonize the matching procedures between 24-h recall data and food composition databases. In the first approach, the 24-h recall data were linked to the local/national food composition databases using standardized procedures, while in the second approach, the 24-h recall data were linked to the German BLS database which includes a larger food list. The aim of this paper was to compare the intakes of energy and eight nutrient components calculated via both approaches. Methods Two non-consecutive 24-h recalls were performed in 1268 adolescents. Energy, carbohydrates, proteins, fat, fiber, water, alcohol, calcium and vitamin C were calculated via the two approaches at individual level. Paired samples t test and Pearson’s correlations were used to compare the mean intakes of energy and the eight mentioned nutrients and to investigate the possible associations between the two approaches.ResultsSmall but significant differences were found between the intakes of energy and the eight food components when comparing both approaches. Very strong and strong correlations (0.70–0.95) were found between both methods for all nutrients.ConclusionThe dietary intakes obtained via the two different linking procedures are highly correlated for energy and the eight nutrients under study.