Cross-sectional and longitudinal associations between sleep duration, sleep quality, and bone stiffness in European children and adolescents

In this large perspective cohort among European children and adolescents, we observed that daytime napping was positively associated with bone stiffness, while short or long sleep duration combined with poor sleep quality was associated with less bone stiffness. Our findings are important for obtaining optimal bone stiffness in childhood.

INTRODUCTION

To examine the cross-sectional and longitudinal associations between sleep duration, sleep quality, and bone stiffness index (SI) in European children and adolescents.

METHODS

Four thousand eight hundred seventy-one children aged 2-11 years from the IDEFICS study and 861 children aged 6-15 years from the subsequent I.Family study were included. Sleep duration (i.e., nocturnal sleep and daytime napping) and sleep quality (i.e., irregularly bedtime routine, have difficulty falling asleep and trouble getting up in the morning) were reported by self-administrated questionnaires. Nocturnal sleep duration was converted into age-specific z-scores, and total sleep duration was classified into short, adequate, and long based on the National Sleep Recommendation. Calcaneal SI of both feet were measured using quantitative ultrasound. Linear mixed-effects models with country as a random effect were used, with adjustments for sex, age, pubertal status, family socioeconomic status, physical activity, screen time, body mass index, and daylight duration.

RESULTS

Nocturnal sleep duration z-scores were positively associated with SI percentiles among participants with adequate sleep duration at baseline. Moreover, the positive association between daytime napping and SI percentiles was more pronounced in participants with adequate sleep duration at baseline, while at 4-year follow-up was more pronounced in participants with short sleep duration. In addition, extreme sleep duration at baseline predicted lower SI percentiles after 4 years in participants with poor sleep quality.

CONCLUSION

The positive associations between nocturnal sleep, daytime napping and SI depended on total sleep duration. Long-term detrimental effect of extreme sleep duration on SI only existed in individuals with poor sleep quality.

A within-sibling pair analysis of lifestyle behaviours and BMI z-score in the multi-centre I.Family study

BACKGROUND AND AIMS

By investigating differences in lifestyle behaviours and BMI in sibling pairs, family-level confounding is minimized and causal inference is improved, compared to cross-sectional studies of unrelated children. Thus, we aimed to investigate within-sibling pair differences in different lifestyle behaviours and differences in BMI z-scores in children and adolescents.

METHODS AND RESULTS

We examined three groups of sibling pairs 1) all same-sex sibling pairs with maximum 4 years age difference (n = 1209 pairs from 1072 families in 8 countries, mean age 10.7 years, standard deviation 2.4 years), 2) sibling pairs discordant for overweight (n = 262) and 3) twin pairs (n = 85). Usual dietary intake was estimated by 24-h recalls and time spent in light (LPA) and moderate-to-vigorous physical activity (MVPA) was measured by accelerometers. Screen time, sleep and dieting for weight loss were assessed by questionnaires. Within all 3 groups of sibling pairs, more time in MVPA was associated with lower BMI z-score. Higher energy intake was associated with higher BMI z-score within twin pairs and within all sibling pairs who were not currently dieting for weight loss. Regarding LPA, screen time or sleep duration, no or inconsistent associations were observed for the three groups of sibling pairs.

CONCLUSIONS

MVPA and energy intake were associated with BMI differences within sibling and twin pairs growing up in the same home, thus independent of family-level confounding factors. Future studies should explore whether genetic variants regulating appetite or energy expenditure behaviours account for weight differences in sibling pairs.

Parents' evaluation of the IDEFICS intervention: an analysis focussing on socio-economic factors, child's weight status and intervention exposure

INTRODUCTION

From April 2008 to August 2010 the Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS (IDEFICS) intervention aimed to encourage healthier diets, higher physical activity levels and lower stress levels among European children and their families. While the intervention was intended to improve children's health, we also wished to assess whether there were unwelcome aspects or negative side-effects. Therefore all parents of children who participated in the IDEFICS intervention were asked for their views on different aspects of the intervention.

METHODS

A total of 10,016 parents of children who participated in the IDEFICS survey and who were involved in the intervention were invited to complete a questionnaire on positive and negative impacts of the intervention. Responses to each of the statements were coded on a four point Likert-type scale. Demographic data were collected as part of the baseline (T0 ) and first follow-up (T1 ) surveys; intervention exposure data was also collected in the T1 follow-up survey. Anthropometric data was collected in the same surveys, and child's weight status was assessed according to Cole and Lobstein. After initial review of the univariate statistics multilevel logistic regression was conducted to analyse the influence of socio-economic factors, child's weight status and intervention exposure on parental responses.

RESULTS

In total 4,997 responses were received. Approval rates were high, and few parents reported negative effects. Parents who reported higher levels of exposure to the intervention were more likely to approve of it and were also no more likely to notice negative aspects. Less-educated and lower income parents were more likely to report that the intervention would make a lasting positive difference, but also more likely to report that the intervention had had negative effects. Parents of overweight and obese children were more likely to report negative effects - above all, that 'the intervention had made their child feel as if he/she was "fat" or "overweight." '

CONCLUSION

While the results represent a broad endorsement of the IDEFICS intervention, they also suggest the importance of vigilance concerning the psychological effects of obesity interventions on overweight and obese children.

Fat, sugar and water intakes among families from the IDEFICS intervention and control groups: first observations from I.Family

BACKGROUND

The objective of this paper is to investigate differences in diets of families in intervention versus control communities 5 years after the Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants intervention ended.

METHODS

Altogether, 4,691 families from the I.Family study with at least one participating parent and one child are included in this analysis. Diet quality indicators, defined as propensities to consume fat, sugar, water and fruit and vegetables, are calculated from a 59-item food frequency questionnaire. Multilevel linear models with random intercepts for study centre are used to determine whether mean diet indicators, calculated at the family level, differed as a function of previous exposure to the intervention.

RESULTS

Families in the intervention communities reported a significantly lower sugar propensity (19.8% vs. 20.7% of total food items, p < 0.01) and a higher water propensity (47.3% vs. 46.0% of total beverages, p < 0.05) compared with families in the control communities, while fat and fruit and vegetables propensities were similar. No significant diet differences between intervention and control children were present at the Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants baseline.

DISCUSSION

This result indicates better diet quality in intervention families, which was not present in children when their diets were assessed before the intervention, and gives some cause for optimism regarding the sustainability of some aspects of the diet intervention.

Behavioural effects of a community-oriented setting-based intervention for prevention of childhood obesity in eight European countries. Main results from the IDEFICS study

OBJECTIVE

The objective of this paper is to evaluate the behavioural effects, as reported by the parents of the participating boys and girls, of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) intervention.

METHODS

The effectiveness of the IDEFICS intervention was evaluated through a cluster-controlled trial in eight European countries (control and intervention communities in each country) including more than 16,000 children. The 2- to 9.9-year-old children in the intervention group were exposed to a culturally adapted intervention that aimed to prevent childhood obesity through the community, schools/kindergartens and family. Parents completed questionnaires to measure water, soft drink and fruit juice intake; fruit and vegetable intake; daily TV viewing and other sedentary behaviours; daily physical activity levels and strengthening of the parent-child relationships at baseline and follow-up (2 years later). Mixed models with an additional random effect for country were used to account for the clustered study design, and results were stratified by sex.

RESULTS

The pan-European analysis revealed no significant time by condition interaction effects, neither for boys nor girls, i.e. the analysis revealed no intervention effects on the behaviours of the IDEFICS children as reported by their parents (F = 0.0 to 3.3, all p > 0.05). Also very few significances were found in the country-specific analyses. Positive intervention effects were only found for sport club participation in Swedish boys, for screen time in weekends for Spanish boys and for TV viewing in Belgian girls.

CONCLUSION

Although no expected intervention effects as reported by the parents on diet, physical activity and sedentary behaviours could be shown for the overall IDEFICS cohort, a few favourable intervention effects were found on specific behaviours in some individual countries. More in-depth analyses of the process evaluation data are needed to obtain more insight into the relationship between the level of exposure to the intervention and its effect.

Adherence to a Mediterranean-like dietary pattern in children from eight European countries. The IDEFICS study

BACKGROUND

Despite documented benefits of a Mediterranean-like dietary pattern, there is a lack of knowledge about how children from different European countries compare with each other in relation to the adherence to this pattern. In response to this need, we calculated the Mediterranean diet score (MDS) in 2-9-year-old children from the Identification and prevention of dietary- and lifestyle-induced health effects in children and infants (IDEFICS) eight-country study.

SUBJECTS AND METHODS

Using 24 h dietary recall data obtained during the IDEFICS study (n=7940), an MDS score was calculated based on the age- and sex-specific population median intakes of six food groups (vegetables and legumes, fruit and nuts, cereal grains and potatoes, meat products and dairy products) and the ratio of unsaturated to saturated fats. For fish and seafood, which was consumed by 10% of the population, one point was given to consumers. The percentages of children with high MDS levels (>3) were calculated and stratified by sex, age and by having at least one migrant parent or both native parents. Demographic (sex and age) and socioeconomic characteristics (parental education and income) of children showing high (>3) vs low (⩽3) MDS levels were examined.

RESULTS

The highest prevalence of children with MDS>3 was found among the Italian pre-school boys (55.9%) and the lowest among the Spanish school-aged girls (26.0%). Higher adherence to a Mediterranean-like dietary pattern was not associated with living in a Mediterranean country or in a highly educated or high-income family, although with some exceptions. Differences in adherence between boys and girls or age groups varied between countries without any general pattern.

CONCLUSIONS

With the exception of Italian pre-schoolers, similar adherence levels to a Mediterranean-like dietary pattern have been observed among European children.

Dietary energy density in young children across Europe

OBJECTIVES

To describe energy density (ED; kcal g(-1)) of dietary intake of European children.

METHODS

From 16, 228 children who participated in the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) baseline examination, 8551 children with 24-h dietary recalls (24-HDR), with plausible reported energy intakes and complete covariate information were included in the present analysis. ED was calculated using two methods: (1) ED including solid foods (EDF) and (2) ED including solid foods and energy-containing beverages (EDF&B). Beverage energy was calculated in kcal per day. Dietary characteristics and body mass index (BMI) z-score of children aged 2 to <6 years and 6 to <10 years were compared between children with an overall EDF below the <25th percentile, between the 25th and 75th percentile as well as above the >75th percentile. Standardised regression coefficients were estimated to assess the association between dietary characteristics, BMI z-score and ED of the diet.

RESULTS

Children with low EDF and EDF&B diets consumed less energy but higher quantity of food and beverages than children with high EDF and EDF&B diets. Consumption of caloric beverages decreased with increasing EDF&B of the diet owing to the relatively low ED of the beverages, in relation to solid foods. Generally, children with low EDF and EDF&B diets showed healthier food choices than peers with higher EDF and EDF&B diets. In this sample, EDF and EDF&B were not associated with BMI z-score.

CONCLUSION

Health promotion strategies should proclaim lower ED diets by means of foods with high water and low fat content and mainly fruit and vegetable components. Excluding caloric beverages from EDF calculation is a useful method to avoid misinterpretation of true exposure to a high energy dense diet. We recommend excluding caloric beverages from EDF calculation when investigating the effect of ED on a certain (health) outcome.

Usual energy and macronutrient intakes in 2-9-year-old European children

OBJECTIVE

Valid estimates of population intakes are essential for monitoring trends as well as for nutritional interventions, but such data are rare in young children. In particular, the problem of misreporting in dietary data is usually not accounted for. Therefore, this study aims to provide accurate estimates of intake distributions in European children.

DESIGN

Cross-sectional setting-based multi-centre study.

SUBJECTS

A total of 9560 children aged 2-9 years from eight European countries with at least one 24-h dietary recall (24-HDR).

METHODS

The 24-HDRs were classified in three reporting groups based on age- and sex-specific Goldberg cutoffs (underreports, plausible reports, overreports). Only plausible reports were considered in the final analysis (N=8611 children). The National Cancer Institute (NCI)-Method was applied to estimate population distributions of usual intakes correcting for the variance inflation in short-term dietary data.

RESULTS

The prevalence of underreporting (9.5%) was higher compared with overreporting (3.4%). Exclusion of misreports resulted in a shift of the energy and absolute macronutrient intake distributions to the right, and further led to the exclusion of extreme values, that is, mean values and lower percentiles increased, whereas upper percentiles decreased. The distributions of relative macronutrient intakes (% energy intake from fat/carbohydrates/proteins) remained almost unchanged when excluding misreports. Application of the NCI-Method resulted in markedly narrower intake distributions compared with estimates based on single 24-HDRs. Mean percentages of usual energy intake from fat, carbohydrates and proteins were 32.2, 52.1 and 15.7%, respectively, suggesting the majority of European children are complying with common macronutrient intake recommendations. In contrast, total water intake (mean: 1216.7 ml per day) lay below the recommended value for >90% of the children.

CONCLUSION

This study provides recent estimates of intake distributions of European children correcting for misreporting as well as for the daily variation in dietary data. These data may help to assess the adequacy of young children's diets in Europe.

Country-specific dietary patterns and associations with socioeconomic status in European children: the IDEFICS study

BACKGROUND/OBJECTIVES

Children from lower socioeconomic status (SES) may be at higher risk of unhealthy eating. We described country-specific dietary patterns among children aged 2-9 years from eight European countries participating in the IDEFICS study and assessed the association of dietary patterns with an additive SES indicator.

SUBJECTS/METHODS

Children aged 2-9 years from eight European countries were recruited in 2007-2008. Principal component analysis was applied to identify dietary country-specific patterns. Linear regression analyses were applied to assess their association with SES.

RESULTS

Two to four dietary patterns were identified in the participating regions. The existence of a 'processed' pattern was found in the eight regions. Also, a 'healthy' pattern was identified in seven of the eight regions. In addition, region-specific patterns were identified, reflecting the existing gastronomic and cultural differences in Europe. The 'processed' pattern was significantly inversely associated with the SES additive indicator in all countries except Sweden, whereas the 'healthy' pattern was positively associated with SES in the Belgian, Estonian, German and Hungarian regions, but was not significant in the Italian, Spanish and Swedish regions.

CONCLUSIONS

A 'processed' pattern and a 'healthy' pattern were found in most of the participating countries in the IDEFICS study, with comparable food item profiles. The results showed a strong inverse association of SES with the 'processed' pattern, suggesting that children of parents with lower SES may be at higher risk of unhealthy eating. Therefore, special focus should be given to parents and their children from lower SES levels when developing healthy eating promotion strategies.

European children's sugar intake on weekdays versus weekends: the IDEFICS study

OBJECTIVES

To compare the intake of total sugars, foods and drinks rich in added sugar, and energy in children on weekdays (Monday-Thursday), Fridays and weekends.

METHODS

Dietary intake (g, kJ, energy %) was assessed using a computerized 24-h recall method in a sample of 2- to 9-year-old children from Belgium, Cyprus, Estonia, Germany, Hungary, Italy, Spain and Sweden who were participating in the IDEFICS baseline study (2007-2008). Analyses were performed in 9497 children by selecting one 24-h recall per child (for comparison of weekdays vs weekends, and Fridays vs weekdays and weekends). Selected stratified analyses were performed by country and age group.

RESULTS

Intake of total sugars exceeded 20 energy % in all countries but one. In the non-stratified analyses, the intakes of total sugars and foods and drinks rich in added sugar were found to be higher on weekends compared with weekdays (both P<0.001), and intakes on Fridays were a mix between intakes on weekdays and weekends. Energy intake did not differ between weekdays and weekends. RESULTS were somewhat heterogeneous, both across countries and age groups.

CONCLUSIONS

High intake of sugar remains an important nutritional problem in children of many European countries. Interventions aiming to prevent this diet pattern may optimize their impact by targeting dietary habits on Fridays and weekends. Furthermore, when conducting dietary assessment in children, data from weekends and Fridays in combination with a selection of Mondays to Thursdays are needed to capture habitual sugar intake. Age and dietary cultures should also be considered in dietary intervention and assessment as effect modifications were seen for both age and country.

Mediterranean diet, overweight and body composition in children from eight European countries: cross-sectional and prospective results from the IDEFICS study

BACKGROUND & AIMS

A Mediterranean-like dietary pattern has been shown to be inversely associated with many diseases, but its role in early obesity prevention is not clear. We aimed to determine if this pattern is common among European children and whether it is associated with overweight and obesity.

METHODS AND RESULTS

The IDEFICS study recruited 16,220 children aged 2-9 years from study centers in eight European countries. Weight, height, waist circumference, and skinfolds were measured at baseline and in 9114 children of the original cohort after two years. Diet was evaluated by a parental questionnaire reporting children's usual consumption of 43 food items. Adherence to a Mediterranean-like diet was calculated by a food frequency-based Mediterranean Diet Score (fMDS). The highest fMDS levels were observed in Sweden, the lowest in Cyprus. High scores were inversely associated with overweight including obesity (OR = 0.85, 95% CI: 0.77; 0.94) and percent fat mass (β = -0.22, 95% CI: -0.43; -0.01) independently of age, sex, socioeconomic status, study center and physical activity. High fMDS at baseline protected against increases in BMI (OR = 0.87, 95% CI: 0.78; 0.98), waist circumference (OR = 0.87, 95% CI: 0.77; 0.98) and waist-to-height ratio (OR = 0.88, 95% CI: 0.78; 0.99) with a similar trend observed for percent fat mass (p = 0.06).

CONCLUSIONS

Although a Mediterranean dietary pattern is inversely associated with childhood obesity, it is not common in children living in the Mediterranean region and should therefore be advocated as part of EU obesity prevention strategies.

Associations between energy intake, daily food intake and energy density of foods and BMI z-score in 2-9-year-old European children

Purpose

The aim of this study was to investigate the associations between proxy-reported energy intake, daily food intake and energy density of foods and body mass index (BMI) z-score in 2–9-year-old European children.

Methods

From 16,225 children who participated in the identification and prevention of dietary- and lifestyle-induced health effects in children and infants (IDEFICS) baseline examination, 9,782 children with 24-h proxy dietary information and complete covariate information were included in the analysis. Participating children were classified according to adapted Goldberg cutoffs: underreports, plausible energy reports and overreports. Energy intake, daily food intake and energy density of foods excluding noncaloric beverages were calculated for all eating occasions. Effect of energy intake, daily food intake and energy density of foods on BMI z-score was investigated using multilevel regression models in the full sample and subsample of plausible energy reports. Exposure variables were included separately; daily food intake and energy intake were addressed in a combined model to check for interactions.

Results

In the group of plausible energy reports (N = 8,544), energy intake and daily food intake were significantly positively associated with BMI z-score. Energy density of foods was not associated with BMI z-score. In the model including energy intake, food intake and an interaction term, only energy intake showed a significantly positive effect on BMI z-score. In the full sample (N = 9,782), only energy intake was significantly but negatively associated with BMI z-score.

Conclusion

Proxy-reporters are subject to misreporting, especially for children in the higher BMI levels. Energy intake is a more important predictor of unhealthy weight development in children than daily food intake.

[Dietary and lifestyle-induced diseases in children. Design, examination modules and study population of the baseline survey of the German IDEFICS cohort]

The European IDEFICS (Identification and Prevention of Dietary- and Lifestyle-induced Health Effects in Children and Infants) Study investigates risk factors of diet- and lifestyle-related diseases in children focusing on overweight, obesity and related metabolic co-morbidities based on a standardized study protocol. In parallel, the IDEFICS study developed, implemented and evaluated strategies for the primary prevention of diet- and lifestyle-related diseases in a controlled, community-oriented design. The prospective cohort study started with a baseline survey from September 2007 to May 2008 in eight European countries, with Germany among them. During the first survey 2,065 German children aged 2-9 years passed a comprehensive examination program. Their parents answered questions on sociodemographic characteristics; media consumption; dietary, activity and sleep patterns; as well as family life and the residential environment. The results of the study will contribute to the development of harmonized European guidelines on diet and lifestyle for health promotion and disease prevention in children.

[Impact of physical activity and exercise on bone health in the life course : a review]

Physical activity and exercise are important determinants for metabolic and cardiovascular health. They also play an important role for bone health in childhood, adolescence, and adulthood. This review summarizes results from observational and intervention studies which evaluated the association between physical activity/exercise and bone health in different life course stages. In childhood and adolescence, physical activity and exercise induce improved bone accrual. In adulthood, mainly in postmenopausal women, long-term exercise programs reduce age-related bone loss. Especially weight-bearing activities seem to have an important osteogenic effect. Children and adolescent show a higher bone accrual until 5 years after cessation of an exercise program compared to their peers, who do not participate in an exercise program. In contrast, adults who quit exercising have a higher decrease in bone stiffness compared to adults who never exercised. This effect was particularly seen in postmenopausal women. Continuous physical activity and exercise over the life course and the implementation of exercise programs in schools and community-based intervention programs can help prevent or even reduce osteoporosis and osteoporosis-related fractures. Due to the lack of prospective longitudinal studies, the supposed long-term sustainable protective effect of physical activity and exercise in childhood and adolescent on bone health in later adulthood is not well established.

[Physical activity and obesity]

One reason for the high prevalence of overweight and obesity might be the differences in lifestyle compared to earlier decades, called the "obesogenic environment." With this, the decline in physical activity (PA) in favor of a sedentary lifestyle is assumed to play an important role. Physical activity or inactivity has a major impact on the development of overweight and obesity as well as on certain metabolic disorders. This review summarizes current scientific knowledge regarding the association between PA and overweight/obesity. The term "physical activity" is defined and different methods of its assessment are introduced. In addition, certain methods for the evaluation/operationalization of collected PA data are described. Finally, some epidemiological studies dealing with the associations between PA and overweight/obesity in children/adolescents as well as in adults are presented.

[The Da Vinci Medical-mental motivation program for supporting lifestyle changes in patients with type 2 diabetes]

BACKGROUND AND OBJECTIVE

Healthy diet and physical activity can improve metabolic control in patients with type 2 diabetes mellitus. However, lifestyle change without external help is difficult: an alteration of mental attitude is necessary to achieve long-term success. A computer-based motivational program ("Da Vinci") has been developed to help patients to change their mental attitudes and beliefs.

METHODS

Patients with type 2 diabetes were supervised by psychological trainers in four sessions at ten study centers. The interactive computer program allowed for identification of motivation restraints and overcoming them. Parameters of carbohydrate metabolism were measured at the beginning and end of the three-months program as well as three and six months after end of program.

RESULTS

All participants (n = 61) developed a positive attitude towards the range of their action and by themselves changed their lifestyle. After three months their weight (-4.6 kg; p < 0.0001), body mass index (-1.1 kg/m2; p < 0.0001), waist circumference (-3.5 cm; p < 0.0001), HbA1c (-0.6 %; p < 0.0001), triglycerides (-31.1 mg/dl; p = 0.033), systolic (-4.0 mmHg; p = 0.005) and diastolic blood pressure (-3.0 mmHg; p = 0.006) had been reduced. Short duration of diabetes and high baseline HbA1c values were predictive for successful HbA1c reduction. Three and six months after end of the program participants were able to maintain or even augment achieved improvements.

CONCLUSION

During the motivational program, which is intended to alter mental attitude and beliefs, but not to teach knowledge about diabetes, participants were able to significantly improve their metabolic control. As these improvements were maintained long-term, this points to sustainable lifestyle change.

Reproducibility of food consumption frequencies derived from the Children's Eating Habits Questionnaire used in the IDEFICS study

OBJECTIVE

To investigate the reproducibility of food consumption frequencies derived from the food frequency section of the Children's Eating Habits Questionnaire (CEHQ-FFQ) that was developed and used in the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) project to assess food habits in 2- to 9-year-old European children.

DESIGN AND METHODS

From a subsample of 258 children who participated in the IDEFICS baseline examination, parental questionnaires of the CEHQ were collected twice to assess reproducibility of questionnaire results from 0 to 354 days after the first examination. Weighted Cohen's kappa coefficients (κ) and Spearman's correlation coefficients (r) were calculated to assess agreement between the first and second questionnaires for each food item of the CEHQ-FFQ. Stratification was performed for sex, age group, geographical region and length of period between the first and second administrations. Fisher's Z transformation was applied to test correlation coefficients for significant differences between strata.

RESULTS

For all food items analysed, weighted Cohen's kappa coefficients (κ) and Spearman's correlation coefficients (r) were significant and positive (P<0.001). Reproducibility was lowest for diet soft drinks (κ=0.23, r=0.32) and highest for sweetened milk (κ=0.68, r=0.76). Correlation coefficients were comparable to those of previous studies on FFQ reproducibility in children and adults. Stratification did not reveal systematic differences in reproducibility by sex and age group. Spearman's correlation coefficients differed significantly between northern and southern European countries for 10 food items. In nine of them, the lower respective coefficient was still high enough to conclude acceptable reproducibility. As expected, longer time (>128 days) between the first and second administrations resulted in a generally lower, yet still acceptable, reproducibility.

CONCLUSION

Results indicate that the CEHQ-FFQ gives reproducible estimates of the consumption frequency of 43 food items from 14 food groups in European children.

The IDEFICS community-oriented intervention programme: a new model for childhood obesity prevention in Europe?

BACKGROUND AND OBJECTIVES

The European Union-as well as other parts of the world-faces a major challenge of increasing incidence of overweight/obesity. In particular, the increase in childhood obesity gives rise to a strong imperative for immediate action. Yet, little is known about the effectiveness of community interventions, and further research in this field is needed. There is, however, a growing consensus that such research should start from the paradigm that the current living environments tend to counteract healthy lifestyles. Questioning these environments thoroughly can help to develop new pathways for sustainable health-promoting communities. Against this background, the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study developed and implemented innovative community-oriented intervention programmes for obesity prevention and healthy lifestyle primarily in children aged 2-10 years in eight European countries: Sweden, Estonia, Germany, Belgium, Hungary, Italy, Spain and Cyprus.

MATERIALS AND METHODS

The IDEFICS community-oriented intervention study mobilised an integrated set of interventional efforts at different levels of society, with the aim of facilitating the adoption of a healthy obesity-preventing lifestyle. The overall programme has been composed of 10 modules: three at community level, six at school level and one for parents. The main focus was on diet, physical activity and stress-coping capacity. The sphere of action encompassed both children and their (grand) parents, schools, local public authorities and influential stakeholders in the community. All materials for the interventions were centrally developed and culturally adapted.

RESULTS

So far, the following has been achieved: focus group research, literature review and expert consultations were done in an early phase as a basis for the development of the intervention modules. The intervention mapping protocol was followed as guide for structuring the intervention research. The overall intervention programme's duration was 2 years, but a longer-term follow-up programme is under development.

CONCLUSIONS

This large-scale European effort is expected to contribute significantly to the understanding of this major public health challenge.

Evaluation of the Children's Eating Habits Questionnaire used in the IDEFICS study by relating urinary calcium and potassium to milk consumption frequencies among European children

BACKGROUND

Measuring dietary intake in children is notoriously difficult. Therefore, it is crucial to evaluate the performance of dietary intake assessment methods in children. Given the important contribution of milk consumption to calcium (Ca) and potassium (K) intakes, urinary calcium (UCa) and potassium (UK) excretions in spot urine samples could be used for estimating correlations with milk consumption frequencies.

OBJECTIVE

The aim of this study was to evaluate the assessment of milk consumption frequencies derived from the Food Frequency Questionnaire section of the Children's Eating Habits Questionnaire (CEHQ-FFQ) used in the IDEFICS (Identification and prevention of dietary- and lifestyle induced health effects in children and infants) study by comparing with UCa and UK excretions in spot urine samples.

DESIGN

This study was conducted as a setting-based community-oriented intervention study and results from the first cross-sectional survey have been included in the analysis.

SUBJECTS

A total of 10,309 children aged 2-10 years from eight European countries are included in this analysis.

METHODS

UCa and UK excretions were measured in morning spot urine samples. Calcium and potassium urine concentrations were standardised for urinary creatinine (Cr) excretion. Ratios of UCa/Cr and UK/Cr were used for multivariate regression analyses after logarithmic transformation to obtain normal distributions of data. Milk consumption frequencies were obtained from the CEHQ-FFQ. Multivariate regression analyses were used to investigate the effect of milk consumption frequencies on UCa and UK concentrations, adjusting for age, gender, study centre, soft drink consumption and frequency of main meals consumed at home.

RESULTS

A significant positive correlation was found between milk consumption frequencies and ratios of UK/Cr and a weaker but still significant positive correlation with ratios of UCa/Cr, when using crude or partial Spearman's correlations. Multivariate regression analyses showed that milk consumption frequencies were predictive of UCa/Cr and UK/Cr ratios, when adjusted for age, gender, study centre, soft drink consumption and frequency of main meals consumed at home. Mean ratios of UK/Cr for increasing milk consumption frequency tertiles showed a progressive increase in UK/Cr. Children consuming at least two milk servings per day had significantly higher mean UCa/Cr and UK/Cr ratios than children who did not. Large differences in correlations between milk consumption frequencies and ratios of UCa/Cr and UK/Cr were found between the different study centres.

CONCLUSION

Higher milk consumption frequencies resulted in a progressive increase in UK/Cr and UCa/Cr ratios, reflecting the higher Ca and K intakes that coincide with increasing milk consumption, which constitutes a major K and Ca source in children's diet.

Developing the IDEFICS community-based intervention program to enhance eating behaviors in 2- to 8-year-old children: findings from focus groups with children and parents

One purpose of 'identification and prevention of dietary- and lifestyle-induced health effects in children and infants' (IDEFICS) is to implement a standardized community-based multi-component healthy eating intervention for younger children in eight different countries. The present study describes important influencing factors for dietary behaviors among children aged 2-8 years old in order to determine the best approaches for developing the dietary components of the standardized intervention. Twenty focus groups with children (74 boys, 81 girls) and 36 focus groups with 189 parents (28 men, 161 women) were conducted. Only in two countries, children mentioned receiving nutrition education at school. Rules at home and at school ranged from not allowing the consumption of unhealthy products to allowing everything. The same diversity was found for availability of (un)healthy products at home and school. Parents mentioned personal (lack of time, financial constraints, preferences), socio-environmental (family, peer influences), institutional (school policies) and physical-environmental (availability of unhealthy products, price, season) barriers for healthy eating. This focus group research provided valuable information to guide the first phase in the IDEFICS intervention development. There was a large variability in findings within countries. Interventions should be tailored at the personal and environmental level to increase the likelihood of behavioral change.

Physical activity is independently related to aerobic capacity in cystic fibrosis

It is unclear whether a relationship between physical activity (PA) and maximal oxygen uptake (V'(O2,max)) exists in cystic fibrosis (CF) and, if so, whether the relationship reflects a direct effect or is mediated by the effects of confounding variables, such as pulmonary or muscle function. The objective of the present study was to determine the relationship between PA and V'(O2,max) in CF while adjusting for possible influences of confounding factors. In total, 36 female and 35 male patients with CF from Germany and Switzerland (aged 12-40 yrs, forced expiratory volume in one second (FEV1) 25-107% predicted) were studied. A Wingate test was employed to measure muscle power. PA was monitored for 7 days and expressed in two ways: 1) average daily accelerometer count (ADAC) and 2) time spent in moderate-to-vigorous PA (MVPA). V'(O2,max) was determined during an incremental cycle exercise test to volitional fatigue. PA was positively related to V'(O2,max). In a multiple linear regression analysis, height, sex, FEV1, muscle power and ADAC (additionally explained variance 2.5%) or time spent in MVPA (additionally explained variance 3.7%) were identified as independent predictors of V'(O2,max). In conclusion, high levels of physical activity in addition to good muscular and pulmonary functions are associated with a high aerobic capacity in cystic fibrosis.

Follow-up of acute pulmonary complications in cystic fibrosis by magnetic resonance imaging: a pilot study

The aim of this pilot study was to obtain information on the value of MRI in the follow-up of atelectasis and pneumonic infiltrates in cystic fibrosis (CF). Six patients aged 5-15 y were initially examined using chest X-ray and magnetic resonance imaging (MRI). Both methods provided identical information. During follow-up, MRI proved suitable to monitor pulmonary complications.

CONCLUSION

MRI of the lung is feasible and valuable in the follow-up of atelectasis and pulmonary infiltrates in CF.

Exercise inhibits epithelial sodium channels in patients with cystic fibrosis

The aim of this study was to determine the effects of a single exercise bout on luminal Cl(-) and Na(+) conductance in the respiratory epithelium of patients with cystic fibrosis (CF). In nine patients with CF and nine healthy control subjects, the transepithelial electrical potential difference (PD) of the nasal respiratory epithelium was recorded, first at rest and then during moderate-intensity exercise. Under both conditions, PD was first measured while superfusing the epithelium with isotonic saline. Then, the effects of amiloride and amiloride plus low chloride plus isoproterenol were determined. Exercise resulted in a significant lower PD compared with rest in patients with CF (-6.6 +/- 16.6 mV versus -33.6 +/- 10.0 mV, p < 0.0001) and control subjects (0.1 +/- 8.7 mV versus -7.1 +/- 5.1 mV, p < 0.01). The effects of amiloride on PD were reduced during exercise compared with rest in patients with CF (+15.8 +/- 9.5 mV versus +26.1 +/- 11.0 mV, p < 0.01) and control subjects (+5.8 +/- 4.8 mV versus +10.0 +/- 3.1 mV, p < 0.01). There was no effect of exercise on chloride conductance in patients with CF and control subjects. We conclude that moderate-intensity exercise partially blocks the amiloride-sensitive sodium conductance in the respiratory epithelium. The inhibition of luminal sodium conductance could increase water content of the mucus in the CF lung during exercise and may, in part, explain the beneficial effects of exercise in patients with CF.

Ventilatory threshold: a useful method to determine aerobic fitness in children?

PURPOSE

The objective of this study was to assess intra- and inter-evaluator reliability and validity of ventilatory threshold (VT) determination in children.

METHODS

At the age of 6-12 yr, 35 children born prematurely and 20 controls born at term performed an incremental continuous cycling task until volitional fatigue. Fifteen-second averages of VE/VO2, VE/VCO2, and respiratory exchange ratio were plotted 1) over time (X-time) and 2) over VO2 (X-VO2). VCO2 was plotted over VO2 only (X-VO2). Two experienced evaluators, blind to the identity of plots, independently assessed VT from X-time and X-VO2 plots on two occasions, 6 wk apart. Thus, for each of the 55 subjects, four VT values were expected from X-time plots and four from X-VO2 plots (2 evaluators, 2 occasions).

RESULTS

VT expressed as VO2 in mL x min(-1) could be determined by both evaluators on both occasions in 40/55 children from X-time and in 45/55 children from X-VO2. VT was significantly different between evaluators for X-time plots. Using X-time plots, intraevaluator ICC were 0.88 and 0.98 and interevaluator ICC were 0.82 and 0.79. The respective values for X-VO2 plots were 0.94 and 0.95, and 0.96 and 0.92. Intra- and inter-evaluator reliability of VT determinations tended to be slightly lower in children born prematurely compared with those born at term. There was a close association between VT and VO2peak (r = 0.92).

CONCLUSION

Plotting gas exchange data over VO2 is likely to be the method of choice for determining VT. Although a minority of children have uninterpretable X-VO, plots, VT can be reliably interpreted in the remainder. Furthermore, VT is a valid marker of aerobic capacity. Thus, VT is a useful measure of aerobic fitness in children.

Measurement of human nasal potential difference to teach the theory of transepithelial fluid transport

We describe a novel student course in membrane physiology in which students record their own nasal potential difference, i.e., the transepithelial potential difference of the respiratory mucosa in the nose. The nasal potential difference monitors directly, and in vivo, changes in the apical cell membrane potential of the respiratory mucosa induced by activators and inhibitors of ion channel activities. Basic principles of transepithelial fluid transport are taught by applying an appropriate perfusion protocol to the respiratory epithelium to either depolarize or hyperpolarize the membrane potential of the luminal cell side, thereby increasing or decreasing the nasal potential difference. This course was given at the Department of Physiology at the University of Würzburg in 1997, and responses of the students as reported on questionnaires were mainly positive.