Comparison of definitions for the metabolic syndrome in adolescents. The HELENA study.

Various definitions are used to define metabolic syndrome in adolescents. This study aimed to compare, in terms of prevalence and differences, five frequently used definitions for this population: International Diabetes Federation, National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP) modified by Cook, pediatric American Heart Association (AHA), World Health Organization, and Jolliffe and Janssen. A sample of 1004 adolescents (12.5-17.0 years) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study was considered. The components of the definitions (waist circumference/BMI, plasma lipids, glycemia, and blood pressure) were applied, and definitions were compared by using crosstabs, sensitivity, specificity, and kappa coefficient. The prevalence of metabolic syndrome varied from 1.6 to 3.8% depending on the used definitions. Crosstabs comparing the definitions showed the fewest cases being misclassified (having metabolic syndrome or not) between NCEP-ATP and AHA. Analyses for kappa coefficient, sensitivity, and specificity confirmed this finding. CONCLUSION: The different definitions do not classify the same adolescents as having MS and prevalence varied between diagnostic methods. The modified NCEP-ATP and the AHA definitions were most analogous in defining subjects as having metabolic syndrome or not. What is known? • Metabolic syndrome is not only a problem of adulthood but is already present in children and adolescents. • Several diagnostic methods are used to define metabolic syndrome in adolescents. What is new? • Comparing the most frequently used definitions of metabolic syndrome in adolescents showed that they do not indicate the same adolescents as having metabolic syndrome. • The modified National Cholesterol Education Program Adult Treatment Panel III and the pediatric American Heart Association definitions were most analogous in defining subjects as having metabolic syndrome or not.

Determinant factors of physical fitness in European children.

OBJECTIVES: This study was designed to explore the determinants of physical fitness in European children aged 6-11 years, cross-sectionally and longitudinally. METHODS: There were sufficient data on 4903 children (50.6 % girls) on measured physical fitness (cardio-respiratory, muscular strength, flexibility, balance, and speed) and possible determinants related to child characteristics, child lifestyle and parental factors. Multivariate and mixed linear regression models were conducted. RESULTS: Age, sex, children's BMI and physical activity were independent and strong determinants of children's fitness. Significant but small effects were found for low maternal BMI, high psychosocial well-being and fruit and vegetable intake as protective determinants. Sleep duration, breakfast intake, parental age and education and paternal BMI did not have a consistently significant effect on physical fitness. The role of determinants depended on children's sex and the specific PF component. Longitudinal analyses especially highlighted the importance of child's BMI as physical fitness determinant, independent of physical activity. CONCLUSIONS: BMI together with physical activity, diet and psychosocial factors are modifiable targets to enhance physical fitness. This calls for policy approaches that combine these factors in a systematic way.

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

PURPOSE: 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. RESULTS: Small 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. CONCLUSION: The dietary intakes obtained via the two different linking procedures are highly correlated for energy and the eight nutrients under study.

Peer effects on obesity in a sample of European children.

This study analyzes peer effects on childhood obesity using data from the first two waves of the IDEFICS study, which applies several anthropometric and other measures of fatness to approximately 14,000 children aged two to nine participating in both waves in 16 regions of eight European countries. Peers are defined as same-sex children in the same school and age group. The results show that peer effects do exist in this European sample but that they differ among both regions and different fatness measures. Peer effects are larger in Spain, Italy, and Cyprus--the more collectivist regions in our sample--while waist circumference generally gives rise to larger peer effects than BMI. We also provide evidence that parental misperceptions of their own children's weight goes hand in hand with fatter peer groups, supporting the notion that in making such assessments, parents compare their children's weight with that of friends and schoolmates.

Influence of sex, age, pubertal maturation and body mass index on circulating white blood cell counts in healthy European adolescents­the HELENA study.

UNLABELLED: Percentiles 10th, 25th, 50th, 75th and 90th are presented for circulating white blood cells (WBC), neutrophils, lymphocytes, monocytes, eosinophils and basophils in healthy European adolescents (12.5-17.5 years, n = 405, 48.9% boys), considering age, sex, puberty and body mass index (BMI). CD3(+) (mature T cells), CD4(+) (T helper), CD8(+) (T cytotoxic), CD16(+)56(+) (natural killer), CD19(+) (B cells), CD3(+)CD45RA(+), CD4(+)CD45RA(+), CD8(+)CD45RA(+) (naïve), CD3(+)CD45RO(+), CD4(+)CD45RO(+) and CD8(+)CD45RO(+) (memory) lymphocytes were also analysed by immunophenotyping. Girls presented higher WBC, neutrophil, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) cell counts and CD3(+)/CD19(+) ratio, and lower CD3(+)CD45RA(+) and CD4(+)CD45RA(+) counts than boys. Age was associated with higher neutrophil counts and CD3(+)/CD19(+), and lower CD19(+) counts; in boys, with lower CD3(+)CD45RA(+), CD4(+)CD45RA(+) and CD8(+)CD45RA(+) counts as well; in girls, with higher WBC, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) counts. Pubertal maturation in boys was associated with lower WBC and lymphocyte counts; in girls, with higher basophil, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) values. BMI was associated with higher WBC counts; in boys, also with higher lymphocyte counts; in girls, with higher neutrophil, CD4(+), CD3(+)CD45RO(+) and CD4(+)CD45RO(+) counts. CONCLUSION: Our study provides normative values for circulating immune cells in adolescents, highlighting the importance of considering sex, age, pubertal maturation and BMI when establishing reference ranges for WBC in paediatric populations.

Associations of early life and sociodemographic factors with menarcheal age in European adolescents.

UNLABELLED: Early menarche has been associated with adult overweight, cardiovascular risk factors, and other diseases. Little is known about the determinants of menarcheal age (MA). Therefore, the main aim of this study was to examine the associations between early life programming factors and menarcheal age in European adolescents. Secondly, the influence of sociodemographical factors on menarcheal age was also studied. A total of 1,069 European girls from the HELENA cross-sectional study, aged 12.5-17.5 years, were included in this study. Using multilevel linear regression models, a possible association between birth weight and length, ponderal index at birth, gestational age, duration of exclusive breastfeeding, and menarcheal age was examined. Associations between geographical gradient, number of siblings, physical activity (PA), dietary factors, and menarcheal age were also examined. After adjustment, menarcheal age was positively associated with birth weight and length (p = 0.01 and p = 0.01). CONCLUSION: These findings confirm that birth weight and length may have a programming effect on menarcheal age. Next to this finding, sociodemographic factors were not associated with menarcheal age.

Associations between macronutrient intake and serum lipid profile depend on body fat in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study.

The present study aimed to investigate the relationships between macronutrient intake and serum lipid profile in adolescents from eight European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) cross-sectional study (2006-7), and to assess the role of body fat-related variables in these associations. Weight, height, waist circumference, skinfold thicknesses, total cholesterol, HDL-cholesterol (HDL-C), LDL-cholesterol, TAG, apoB and apoA1 were measured in 454 adolescents (44% boys) aged 12.5-17.5 years. Macronutrient intake (g/4180 kJ per d (1000 kcal per d)) was assessed using two non-consecutive 24 h dietary recalls. Associations were evaluated by multi-level analysis and adjusted for sex, age, maternal education, centre, sum of four skinfolds, moderate-to-vigorous physical activity, sedentary behaviours and diet quality index for adolescents. Carbohydrate intake was inversely associated with HDL-C (ß = - 0.189, P< 0.001). An inverse association was found between fat intake and TAG (ß = - 0.319, P< 0.001). Associations between macronutrient intake and serum lipids varied according to adiposity levels, i.e. an inverse association between carbohydrate intake and HDL-C was only observed in those adolescents with a higher waist:height ratio. As serum lipids and excess body fat are the major markers of CVD, these findings should be considered when developing strategies to prevent the risk of CVD among adolescents.

Dietary lipid intake only partially influences variance in serum phospholipid fatty acid composition in adolescents: impact of other dietary factors.

The present study aimed to assess the correlation between food and fatty acid (FA) intake and the serum phospholipid (PL) FA status in European adolescents and explored the percentage of variation in serum PL FA that could be attributed to dietary habits. Participants included 528 adolescents recruited in the HELENA Study. Dietary intake was assessed by two, self-administered, non-consecutive 24-h recalls. PL FA concentrations were measured in fasting venous serum samples. Reduced rank regressions were applied to examine the combined effect of food intakes. Results indicated that the variance in serum PL FA in adolescents, that could be explained by diet varied from 7.0% for MUFA to 14.2% for n-3FA. The variance in the long-chain n-3FA was mainly explained by fish intake but also by coffee and tea consumption. In conclusion this study indicated that dietary intake influences the serum PL FA status to a limited amount but that also other factors interfere. However, dietary intake is important as it is among those factors that could be modified. Furthermore, the results suggest that the overall dietary habits should be considered instead of only the consumption of single foods or nutrients, as the medium of the food or concomitant intake of foods and nutrients might interact and as such influence absorption or metabolism.

The association between childhood stress and body composition, and the role of stress-related lifestyle factors--cross-sectional findings from the baseline ChiBSD survey.

BACKGROUND: Stress has been hypothesised to be involved in obesity development, also in children. More research is needed into the role of lifestyle factors in this association. PURPOSE: This study investigates the cross-sectional relationship between stress and body composition and, more importantly, the possible moderating or mediating role of lifestyle factors. METHODS: A total of 355 Belgian children (5-10 years old) participating in the baseline 'Children's Body composition and Stress' survey were included in this study. The following variables were studied: psychosocial stress (i.e. stressful events, emotions and behavioural/emotional problems, salivary cortisol), stress-related lifestyle factors (high-caloric snack consumption frequency, screen exposure time and sleep duration) and body composition parameters [BMI z-score, waist to height ratio (WHtR)]. Using linear regression analyses (adjusted for sex, age and socio-economic status), the relation between stress and body composition and, more importantly, the possible moderating or mediating role of lifestyle factors was tested. RESULTS: No association was observed between body composition and negative emotions, conduct and emotional problems and salivary cortisol. However, negative life events were positively and happiness was negatively associated with BMI z-score and WHtR. Peer problems and WHtR were positively associated in girls only. These associations were not significantly reduced after correction for lifestyle factors. Nevertheless, all lifestyle parameters moderated one or more stress-body composition associations, resulting in even more significant relations after subgroup analysis. CONCLUSION: Childhood stress was positively related to both overall and central adiposity measures with lifestyle factors acting as moderators but not as mediators. Thus, lifestyle could be a vulnerability factor in stress-induced adiposity, creating a perspective for multi-factorial obesity prevention, targeting stress and lifestyle factors in parallel.

Dietary intake and food sources of total and individual polyunsaturated fatty acids in the Belgian population over 15 years old.

Advances in our knowledge of the physiological functions of dietary polyunsaturated fatty acids (PUFAs) have led to an increased interest in food sources and the level of dietary intake of these nutrients. Up to now, no representative data was available for the Belgian adult population. This study aimed to describe data on the intake and food sources of total and individual omega-6 and omega-3 PUFA for the Belgian population over 15 years old. PUFA intakes were assessed for 3,043 Belgian adults, based on two non-consecutive 24 h recalls. Usual intakes were calculated using the multiple source method. The results showed that the intake of linoleic acid (LA) is in accordance with the recommendation for almost all Belgian adults. However, the intake of omega-3 PUFA is suboptimal for a large part of the studied population and also the intake of total PUFA should be increased for a part of the population. The main food source of LA and α-linolenic acid (ALA) was the group of fats and oils (60.6 % for LA and 53.1 % for ALA). Fish and fish products were the most important sources of long chain omega-3 PUFA. Age influenced fatty acids intake, with higher intake of omega-3 PUFA in the older age groups. To fill the gap between the intake and recommendation of total PUFA, and in particular omega-3 PUFA, sustainable strategies and efficient consumer communication strategies will be needed.

Cortisone in hair of elementary school girls and its relationship with childhood stress.

UNLABELLED: Children may be exposed to stressful situations with adverse effects on their physiological and psychological health. As cortisone may be a useful additional biomarker for stress research and as it has been shown to be detectable in human hair, this study measured physiological concentrations of hair cortisone in 223 elementary school girls and explored its relationship with child-reported estimates of stress, more specifically questionnaires on major life events (i.e., Coddington Life Events Scale for Children), emotions (i.e., anger, anxiety, sadness, and happiness), and coping strategies (i.e., emotion- versus problem-focused coping). Cortisone concentrations were positively correlated with the overall life event score for the past 6 months (rho = 0.223, p = 0.004), as well as with the negative event score for this period (rho = 0.227, p = 0.003; N = 165). Cortisone did not correlate with emotions or coping styles reported by the children. CONCLUSION: Despite its exploratory nature, this study may suggest elevated hair cortisone concentrations under psychosocial stress in young children. Although the observed findings should be interpreted with prudence, this study may encourage further research elucidating the potential importance and relevance of hair cortisone analysis as an additional or substituting stress biomarker for hair cortisol.

Intake and serum profile of fatty acids are weakly correlated with global dietary quality in European adolescents.

OBJECTIVE: The present study assessed whether compliance with the Food-Based Dietary Guidelines is related to habitual fatty acid (FA) intake and blood lipid parameters. METHODS: Dietary information was collected by two non-consecutive 24-h recalls in 1804 European adolescents. Compliance with the Food-Based Dietary Guidelines was expressed by calculating the Diet Quality Index for Adolescents (DQI-A). Blood samples were collected in a randomly selected subset (n = 552). Relations between FA intake/serum concentrations and DQI-A were tested with multilevel regression analysis to correct for the study design (clustering within cities). Analyses were stratified for gender; age was entered as a covariate. RESULTS: Better DQI-A scores were related to increased proportional intakes of energy from total fat, saturated FA, monounsaturated FA, and cholesterol (P < 0.001), whereas no significant association was observed with polyunsaturated FA intakes. In adolescents with higher compared with lower DQI-A scores, dairy products contributed more (21.0% versus 12.7%) and low-nutrient, energy-dense items contributed less (17.2% versus 26.3%) to the intake of total fat. A positive association was observed between the DQI-A scores and serum concentrations of eicosapentaenoic acid and docosahexaenoic acid (all P < 0.005). The latter, however, was significant only in girls. In boys, higher DQI-A scores were inversely associated with serum cholesterol concentrations (P < 0.05). CONCLUSION: Although compliance with the Food-Based Dietary Guidelines was not always associated with a favorable FA intake pattern, a significant favorable association with some serum biomarkers was observed. This outcome underlines the importance of considering dietary habits instead of single-nutrient intakes.

Validation of the Diet Quality Index for Adolescents by comparison with biomarkers, nutrient and food intakes: the HELENA study.

Food-based dietary guidelines (FBDG) aim to address the nutritional requirements at population level in order to prevent diseases and promote a healthy lifestyle. Diet quality indices can be used to assess the compliance with these FBDG. The present study aimed to investigate whether the newly developed Diet Quality Index for Adolescents (DQI-A) is a good surrogate measure for adherence to FBDG, and whether adherence to these FBDG effectively leads to better nutrient intakes and nutritional biomarkers in adolescents. Participants included 1804 European adolescents who were recruited in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study. Dietary intake was assessed by two, non-consecutive 24 h recalls. A DQI-A score, considering the components' dietary quality, diversity and equilibrium, was calculated. Associations between the DQI-A and food and nutrient intakes and blood concentration biomarkers were investigated using multilevel regression analysis corrected for centre, age and sex. DQI-A scores were associated with food intake in the expected direction: positive associations with nutrient-dense food items, such as fruits and vegetables, and inverse associations with energy-dense and low-nutritious foods. On the nutrient level, the DQI-A was positively related to the intake of water, fibre and most minerals and vitamins. No association was found between the DQI-A and total fat intake. Furthermore, a positive association was observed with 25-hydroxyvitamin D, holo-transcobalamin and n-3 fatty acid serum levels. The present study has shown good validity of the DQI-A by confirming the expected associations with food and nutrient intakes and some biomarkers in blood.

Caucasian children's fat mass: routine anthropometry v. air-displacement plethysmography.

The present paper will use fat mass percentage (FM%) obtained via BOD POD® air-displacement plethysmography (FMADP%) to examine the relative validity of (1) anthropometric measurements/indices and (2) of FM% assessed with equations (FMeq%) based on skinfold thickness and bioelectrical impedance (BIA). In 480 Belgian children (aged 5-11 years) weight, height, skinfold thickness (triceps and subscapular), body circumferences (mid-upper arm, waist and hip), foot-to-foot BIA (Tanita®) and FMADP% were measured. Anthropometric measurements and calculated indices were compared with FMADP%. Next, published equations were used to calculate FMeq% using impedance (equations of Tanita®, Tyrrell, Shaefer and Deurenberg) or skinfold thickness (equations of Slaughter, Goran, Dezenberg and Deurenberg). Both indices and equations performed better in girls than in boys. For both sexes, the sum of skinfold thicknesses resulted in the highest correlation with FMADP%, followed by triceps skinfold, arm fat area and subscapular skinfold. In general, comparing FMeq% with FMADP% indicated mostly an age and sex effect, and an increasing underestimation but less dispersion with increasing FM%. The Tanita® impedance equation and the Deurenberg skinfold equation performed the best, although none of the used equations were interchangeable with FMADP%. In conclusion, the sum of triceps and subscapular skinfold thickness is recommended as marker of FM% in the absence of specialised technologies. Nevertheless, the higher workload, cost and survey management of an immobile device like the BOD POD® remains justified.

Prevalence of negative life events and chronic adversities in European pre- and primary-school children: results from the IDEFICS study.

BACKGROUND: Children are not always recognized as being susceptible to stress, although childhood stressors may originate from multiple events in their everyday surroundings with negative effects on children's health. METHODS: As there is a lack of large-scale, European prevalence data on childhood adversities, this study presents the prevalence of (1) negative life events and (2) familial and social adversities in 4637 European pre- and primary-school children (4-11 years old), using a parentally-reported questionnaire embedded in the IDEFICS project ('Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS'). RESULTS: The following findings were observed: (1) Certain adversities occur only rarely, while others are very regular (i.e. parental divorce); (2) A large percentage of children is shielded from stressors, while a small group of children is exposed to multiple, accumulating adversities; (3) The prevalence of childhood adversity is influenced by geographical location (e.g. north versus south), age group and sex; (4) Childhood adversities are associated and co-occur, resulting in potential cumulative childhood stress. CONCLUSIONS: This study demonstrated the importance of not only studying traumatic events but also of focusing on the early familial and social environment in childhood stress research and indicated the importance of recording or monitoring childhood adversities.

Children's Body composition and Stress - the ChiBS study: aims, design, methods, population and participation characteristics.

BACKGROUND: The 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. METHODS: The 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. RESULTS: The 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%). DISCUSSION: The 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.

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 children's 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.

Mineral concentrations in hair of Belgian elementary school girls: reference values and relationship with food consumption frequencies.

Although evidence suggests that hair elements may reflect dietary habits and/or mineral intake, this topic remains controversial. This study therefore presents age-specific reference values for hair concentrations of Ca, Cu, Fe, Na, Mg, P and Zn using the LMS method of Cole, and investigates the relationship between dietary habits (i.e. food consumption frequencies) and hair mineral concentrations in 218 Belgian elementary school girls by reduced rank regression (RRR). Hair minerals were quantitatively determined via inductively coupled plasma-mass spectrometry after microwave-assisted acid digestion of 6-cm long vertex posterior hair samples. The Children's Eating Habits Questionnaire-Food Frequency Questionnaire was used to obtain information on food consumption frequency of 43 food items in the month preceding hair collection. The established reference ranges were in line with data for other childhood or adolescent populations. The retained RRR factors explained 40, 50, 45, 46, 44 and 48 % of the variation of Ca, Cu, Fe, Mg, P and Zn concentrations in hair, respectively. Although this study demonstrated that a large proportion of hair mineral variation may be influenced by food consumption frequencies in elementary school girls, a number of food groups known to be rich sources of minerals did not show a relation with certain hair minerals. Future research should focus on mechanisms and processes involved in mineral incorporation and accumulation in scalp hair, in order to fully understand the importance and influence of diet on hair minerals.

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

To evaluate the impact of stress on children's 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.

Dietary fatty acid intake, its food sources and determinants in European adolescents: the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study.

Dietary fatty acids (FA) play a role in several (patho)physiological processes at any age, and different FA have different effects on lipid status and health outcome. The present study aims to describe the FA intake and its main food sources in a population of healthy European adolescents and to assess the variation in intake as a function of non-dietary factors. FA intake was assessed with 24 h recall interviews in 1804 adolescents aged 12·5-17·5 years. Usual intakes were calculated using the multiple source method. Multilevel analyses, adjusting for study centre, were used to investigate the influence of non-dietary factors. The mean total fat intake was 33·3 (sd 1·2) % of total energy intake (%E). The mean SFA intake was 13·8 (sd 1·2) %E, with 99·8 % of the population exceeding the recommendations. SFA was mainly delivered by meat and cake, pies and biscuits. In most adolescents, the PUFA intake was too low, and 35·5 % of the population did not achieve the minimum recommended intake for α-linolenic acid (ALA). The main determinants of FA intake in the present study population were age and sex, as well as physical activity in the male subgroup. No contributions of body composition, socio-economic status or sexual maturation to the variance in FA intake were observed. In conclusion, the most important public health concerns regarding FA intake in this adolescent population were the low intake of ALA and the high intake of SFA, mainly seen in the younger-aged boys. In this group the major contributor to SFA was meat.