Analysis of the association of leptin and adiponectin concentrations with metabolic syndrome in children: Results from the IDEFICS study

BACKGROUND AND AIMS

Adipokines may play a role in the pathogenesis of the metabolic syndrome (MetS) in children. We aimed to evaluate the association of leptin, adiponectin, and its ratio (L/A ratio) with the metabolic syndrome (MetS) in a subsample of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) cohort.

METHODS AND RESULTS

Leptin, adiponectin and MetS parameters were measured in a subsample of 1253 children (3-9.9 years) participating to the IDEFICS study, grouped as: Non-OW (underweight/normal weight) and OW/Ob (overweight/obese). MetS was defined using the sex- and age-specific cut-offs based on the distribution of MetS components in the IDEFICS cohort. The prevalence of the MetS among OW/Ob was 24.8% and 27.1% in boys and girls respectively, whereas ≤2% among Non-OW. OW/Ob had significantly higher leptin and L/A ratio as compared to Non-OW. Significantly higher leptin was found in OW/Ob with MetS as compared with OW/Ob without MetS. Significantly lower adiponectin was observed only in OW/Ob girls as compared to Non-OW. A 1SD increase in leptin and L/A ratio z-scores or a 1SD decrease in adiponectin z-score were significantly associated with higher risk of MetS. After adjustment for BMI or body fat mass (BFM) the association remained significant only for leptin.

CONCLUSION

We showed that in European children, higher leptin concentration is associated with MetS, even after adjusting for BMI or BFM, confirming an early role of leptin in MetS, while the association of adiponectin with MetS seems be mediated by body fat in this age range.

Differential outcome of the IDEFICS intervention in overweight versus non-overweight children: did we achieve 'primary' or 'secondary' prevention?

BACKGROUND

The aim of this study was to explore whether the IDEFICS intervention had a differential effect on 11,041 children's weight trajectories depending on their baseline body mass index status.

METHODS

Two subgroups of children are considered in the present analysis: those who were overweight or obese prior to the intervention and those who were neither overweight nor obese.

RESULTS

Among children in all eight countries who did not have prevalent overweight or obesity (OWOB) at baseline, 2 years later, there was no significant difference between intervention and control groups in risk of having developed OWOB. However, we observed a strong regional heterogeneity, which could be attributed to the presence of one distinctly outlying country, Belgium, where the intervention group had increased risk for becoming overweight. In contrast, among the sample of children with prevalent OWOB at baseline, we observed a significantly greater probability of normalized weight status after 2 years. In other words, a protective effect against persistent OWOB was observed in children in intervention regions compared with controls, which corresponded to an adjusted odds ratio of 0.76 (95% confidence interval: 0.58, 0.98).

DISCUSSION

This analysis thus provided evidence of a differential effect of the IDEFICS intervention, in which children with overweight may have benefited without having been specifically targeted. However, no overall primary preventive effect could be observed in children without initial overweight or obesity.

Process evaluation of the IDEFICS school intervention: putting the evaluation of the effect on children's objectively measured physical activity and sedentary time in context

OBJECTIVES

The first aim was to describe the intervention implementation and reception with specific regard to physical activity (PA) within Belgian schools participating in the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) intervention. Second, we examined if a higher intervention process score in schools showed more favourable effects on children's objectively measured PA and sedentary time (ST).

METHODS

The IDEFICS intervention focused on improving children's health behaviour (including PA) at the community, school/kindergarten and family level. Five process evaluation questionnaires completed by school working groups, and (physical education) teachers were used for the process evaluation of four intervention modules (school working groups, healthy weeks, school environment, health-related physical education and PA). Items were summed to calculate a total intervention process score per school. Schools were subdivided into three groups (low, medium and high score). Multilevel models were used to examine if changes in PA or ST differed between schools with a low, medium or high score. In total, 333 children (54.1% girls, mean age 6.0 ± 1.5 years) from 34 intervention schools (18 pre-schools and 16 primary schools) in the town of Geraardsbergen, Belgium, provided valid accelerometer data for two weekdays and one weekend day.

RESULTS

Mean intervention process score (maximum value = 44) was 20.9 ± 5.8 for schools. The breakdown per module showed which components were implemented and received well and which components could have been improved. After the intervention, the decrease in light PA and increase in ST was much higher in children from primary schools with a low intervention process score, whereas the behaviours remained relatively stable in children from primary schools with a medium or high score. The change in moderate to vigorous PA did not differ significantly between schools with a low, medium or high score.

CONCLUSION

The IDEFICS intervention was relatively able to prevent unfavourable changes in ST and light PA in schools with a medium and high intervention process score. Further process evaluation research is needed to obtain a more profound picture of the IDEFICS intervention process.

Impact of a community based health-promotion programme in 2- to 9-year-old children in Europe on markers of the metabolic syndrome, the IDEFICS study

INTRODUCTION

One objective of 'Identification and prevention of Dietary-and lifestyle-induced health EFfects In Children and infantS', the IDEFICS study, was to implement a community-oriented childhood obesity prevention intervention in eight European countries.

OBJECTIVE

To assess the effect of an obesity primary prevention programme on metabolic markers.

METHODS

The study had a non-randomized cluster-experimental design. In each country, children were recruited from distinct communities serving as intervention and control regions. Health examinations were done during 2007-2008 before the intervention (T0 ) and during 2009-2010 (T1 ). Children with results available from T0 and T1 on blood pressure, waist circumference and at least one blood-marker (fasting glucose, insulin, HOMA-IR, HbA1c, HDL- and LDL-cholesterol, triglycerides, C-reactive protein) were included. A metabolic syndrome (MetS) score was calculated.

RESULTS

A total of 7,406 children (age 2-9.9 years) of the 16,228 participating at T0 provided the necessary data. No effect of the intervention was seen on insulin, HOMA-IR, CRP or the MetS score. Overall fasting glucose increased less in the intervention than in the control region, a pattern driven by three of the eight countries and more pronounced in children of parents with low education. Overall, HbA1c and waist circumference increased more and blood pressure less in the intervention regions.

CONCLUSION

We observed no convincing effect of the intervention on markers of the metabolic syndrome. We identified diverse patterns of change for several markers of uncertain relation to the intervention.

Implementation of the IDEFICS intervention across European countries: perceptions of parents and relationship with BMI

OBJECTIVES

The primary aim of the present study was to obtain insight into parents' perception of the IDEFICS intervention at the school or preschool/kindergarten and community levels and whether they received specific materials related to the intervention. The secondary aim was to analyse whether parents who reported higher levels of exposure to the IDEFICS intervention had children with more favourable changes in body mass index (BMI) z-scores between baseline and after 2 years of intervention.

METHODS

Process evaluation of the IDEFICS intervention investigated the implementation of the 2-year intervention in the intervention communities. Intervention group parents (n = 4,180) in seven countries (Belgium, Cyprus, Estonia, Germany, Italy, Spain and Sweden) answered questions about their exposure to the IDEFICS study. To analyse the relationship between exposure and BMI z-score, a composite score was calculated for exposure at the setting and at the community levels.

RESULTS

The frequency of parental exposure to the IDEFICS messages not only through the community but also through the (pre)school/kindergarten was lower than what was intended and planned. The dose received by the parents was considerably higher through the (pre)school/kindergarten settings than that through the community in all countries. Efforts by the settings or communities related to fruit and vegetable consumption (range 69% to 97%), physical activity promotion (range 67% to 91%) and drinking water (range 49% to 93%) were more visible and also realized more parental involvement than those related to TV viewing, sleep duration and spending time with the family (below 50%). Results showed no relation of parental exposure at the setting or the community level on more favourable changes in children's BMI z-scores for the total sample. Country-specific analyses for parental exposure at the setting level showed an expected positive effect in German girls and an unexpected negative effect in Italian boys.

CONCLUSION

Parental exposure and involvement in the IDEFICS intervention in all countries was much less than aimed for, which might be due to the diverse focus (six key messages) and high intensity and duration of the intervention. It may also be that the human resources invested in the implementation and maintenance of intervention activities by the study centres, the caretakers and the community stakeholders were not sufficient. Higher levels of parental exposure were not related to more favourable changes in BMI z-scores.

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.

Effects of a community-oriented obesity prevention programme on indicators of body fatness in preschool and primary school children. Main results from the IDEFICS study

BACKGROUND/OBJECTIVES

Childhood obesity is a major public health concern but evidence-based approaches to tackle this epidemic sustainably are still lacking. The Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS (IDEFICS) study investigated the aetiology of childhood obesity and developed a primary prevention programme. Here, we report on the effects of the IDEFICS intervention on indicators of body fatness.

SUBJECTS/METHODS

The intervention modules addressed the community, school and parental level, focusing on diet, physical activity and stress-related lifestyle factors. A cohort of 16,228 children aged 2-9.9 years - about 2000 per country - was equally divided over intervention and control regions. (Participating countries were Sweden, Germany, Estonia, Hungary, Cyprus, Italy, Spain and Belgium.) We compared the prevalence of overweight/obesity and mean values of body mass index z-score, per cent body fat and waist-to-height ratio over 2 years of follow-up. Mixed models adjusting for age and socioeconomic status of the parents and with an additional random effect for country accounted for the clustered study design.

RESULTS

The prevalence of overweight and obesity increased in both the intervention and control group from 18.0% at baseline to 22.9% at follow-up in the control group and from 19.0% to 23.6% in the intervention group. The difference in changes between control and intervention was not statistically significant. For the cohort as a whole, the changes in indicators of body fatness did not show any clinically relevant differences between the intervention and control groups. Changes in favour of intervention treatment in some indicators were counterbalanced by changes in favour of the control group in some other indicators.

CONCLUSIONS

Over the 2-year-observation period, the IDEFICS primary prevention programme for childhood obesity has not been successful in reducing the prevalence of overweight and obesity nor in improving indicators of body fatness in the target population as a whole.

Effectiveness of the IDEFICS intervention on objectively measured physical activity and sedentary time in European children

BACKGROUND

This paper reports on the effectiveness of the prevention of dietary- and lifestyle-induced health effects in children and infants (IDEFICS) intervention on objectively measured physical activity (PA) and sedentary time (ST) in 2- to 9.9-year-old European boys and girls.

METHODS

The intervention was evaluated after 2 years through a non-randomized cluster-controlled trial in eight European countries (one control and one intervention community per country). All children in the intervention group received a culturally adapted childhood obesity prevention programme through the community, schools/kindergartens and family. A random sub-sample of children participating in the IDEFICS study wore an accelerometer at baseline and follow-up for at least 3 days (n = 9,184). Of this sample, 81% provided valid accelerometer data at baseline (n = 7,413; 51% boys; 6.21 ± 1.76 years; boys: 617 ± 170 cpm day(-1) ; girls 556 ± 156 cpm day(-1) ) and 3,010 children provided valid accelerometer data at baseline and during the follow-up survey 2 years later.

RESULTS

In boys and girls, no significant differences in PA and ST were found between intervention and control groups over 2 years. Strong temporal effects were found in the total sample of boys and girls: the percentage of time spent in light PA per day decreased by 4 percentage points in both boys and girls between baseline and follow-up (both: p < 0.001), while time spent in ST per day increased by 4 percentage points in both sexes over time (both: p < 0.001). Percentage of time spent in moderate-to-vigorous PA per day remained stable over time in boys and girls.

CONCLUSION

Despite the socio-ecological approach and implementation of a culturally adapted intervention in each country, no effects of the IDEFICS intervention were found on children's objectively measured PA and ST. Behavioural interventions for children may need to enhance specificity and intensity at the family level using other behaviour change techniques and more direct strategies to reach parents.

Metabolic syndrome in young children: definitions and results of the IDEFICS study

OBJECTIVE

To estimate the prevalence of the metabolic syndrome (MetS) using reference standards obtained in European children and to develop a quantitative MetS score and describe its distribution in children.

DESIGN AND METHODS

Population-based survey in eight European countries, including 18745 children 2.0 to 10.9 years, recruited during a second survey. Anthropometry (weight, height and waist circumference), blood pressure and serum-fasting triglycerides, HDL cholesterol, glucose and insulin were measured. We applied three widely accepted definitions of the pediatric MetS and we suggest a new definition, to guide pediatricians in decisions about close monitoring or even intervention (values of at least three of the MetS components exceeding the 90th or 95th percentile, respectively). We used a z-score standardisation to calculate a continuous score combining the MetS components.

RESULTS

Among the various definitions of MetS, the highest prevalence (5.5%) was obtained with our new definition requiring close observation (monitoring level). Our more conservative definition, requiring pediatric intervention gives a prevalence of 1.8%. In general, prevalences were higher in girls than in boys. The prevalence of metabolic syndrome is highest among obese children. All definitions classify a small percentage of thin or normal weight children as being affected. The metabolic syndrome score shows a positive trend with age, particularly regarding the upper percentiles of the score.

CONCLUSIONS

According to different definitions of pediatric MetS, a non-negligible proportion of mostly prepubertal children are classified as affected. We propose a new definition of MetS that should improve clinical guidance. The continuous score developed may also serve as a useful tool in pediatric obesity research. It has to be noted, however, that the proposed cutoffs are based on a statistical definition that does not yet allow to quantify the risk of subsequent disease.

A controlled study of lifestyle treatment in primary care for children with obesity

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Lifestyle intervention is the most common treatment strategy for children with obesity. Specialized units for the care of children with obesity report significant effects of lifestyle treatment. In children, the physical activity component in lifestyle treatment is often well accepted.

WHAT THIS STUDY ADDS

Two lifestyle treatment programmes in primary care for children with obesity both gave a reduction of body mass index significantly greater than the change observed in a non-intervention comparison group of children with obesity. Substituting one-third of nurse-led treatment sessions with sessions led by physiotherapists in one of the programmes did not improve the outcome. The efficacy of treatment in primary care seems to be comparable to that reported in the literature.

OBJECTIVE

To evaluate the efficacy of lifestyle treatment in primary care for children with obesity.

METHODS

In a multicentre study, sixty-four 9- to 13-year-old children with obesity were randomized to one of two 12-month lifestyle treatment programmes. The only difference between the programmes was that a physiotherapist substituted the nurse in one-third of the sessions in an attempt to stimulate physical activity. For comparison, children with normal weight and overweight, and an age-, sex- and body mass index-matched non-intervention group of children with obesity were used.

RESULTS

Anthropometry and laboratory data differed significantly between children with obesity and normal weight at baseline. The follow-up at the end of treatment was attended by 55 children with obesity, 28 and 27 in each treatment arm. The mean (standard deviation) body mass standard deviation score changed by -0.36 (0.3) in the arm involving a physiotherapist and by -0.33 (0.2) in the other arm. These outcomes were not significantly different. Both reductions were significantly greater than the change of -0.14 (0.3) observed in the non-intervention comparison group of children with obesity

CONCLUSION

The efficacy of treatment in primary care for children with obesity seems to be comparable to that reported in the literature. ISRCTN44919688.

Parental perceptions of and concerns about child's body weight in eight European countries--the IDEFICS study

OBJECTIVES

To evaluate parental perceptions of and concern about child's body weight and general health in children in a European cohort.

DESIGN

Cross-sectional multi-centre study in eight European countries.

PARTICIPANTS

16,220 children, ages 2-9 years.

METHODS

Parents completed a questionnaire regarding children's health and weight and concern about overweight and underweight. Objective children's weight categories from the International Obesity Task Force were used. Logistic regression models were utilized to identify predictors of accurate weight perception.

RESULTS

Parental weight perception corresponded overall to children's mean body mass index (BMI) z-scores, with important exceptions. About one-third of the total indicated concern about underweight, paradoxically most often parents of children in the overweight or obesity categories. In 63%, parents of children in the overweight category marked 'proper weight'. The strongest predictor for accurate parental weight perception for children with overweight and obesity was BMI z-score (odds ratio [OR] = 7.2, 95% confidence interval [CI] 6.1-8.7). Compared to Southern Europe, ORs for accurate parental weight perception were 4.4 (95% CI 3.3-6.0) in Northern Europe and 3.4 (95% CI 2.7-4.2) in Central Europe.

CONCLUSION

Parents of children categorized as being overweight or obese systematically underestimated weight. Parents differed regionally regarding accurate weight perception and concern about overweight and underweight.

Relation between bone mineral density, biological markers and anthropometric measures in 4-year-old children: a pilot study within the IDEFICS study

OBJECTIVE

To investigate the relationship between bone mineral density (BMD), anthropometric characteristics, levels of biological markers for growth, bone turnover, insulin resistance and fat mass in 4-year-old Swedish children.

METHODS

Descriptive study with 41 children (28 boys) who had anthropometric measurements and blood samples taken and heel dual-energy X-ray absorptiometry and laser (DXL) performed. The study participants were divided into groups of normal-weight (n=28) and overweight or obese (n=13) children.

RESULTS

There was a significant difference in bone mineral content (BMC), BMD and bone mineral apparent density (BMAD) between overweight and normal-weight children. There was a significant positive correlation between BMC, BMD, BMAD and body mass index standard deviation scores (r=0.36, 0.34 and 0.29, P<0.01, respectively), waist circumference (r=0.32, 0.30, P<0.01 and r=0.26, P<0.05, respectively) and subscapular skinfold (r=0.26, 0.25 and 0.23, P<0.05, respectively). BMC and BMD correlated significantly with the sum of skinfold measures (r=0.25 and 0.23, P<0.05, respectively). Adiponectin was significantly inversely correlated with BMC, BMD and BMAD (r=-0.41, -0.40 and -0.41, P<0.01, respectively). Adiponectin was not correlated with skinfold measures. Multiple regression analysis revealed that adiponectin was an independent determinant of BMD, BMC and BMAD.

CONCLUSION

To our knowledge, this is the first study investigating BMD assessed by heel-DXL in relation to anthropometry and metabolic markers in 4-year-old children. Adiponectin was significantly inversely correlated with bone mass parameters. Adiponectin may have an independent role in bone development and metabolism in young children.

The IDEFICS validation study on field methods for assessing physical activity and body composition in children: design and data collection

OBJECTIVE

To describe the design, measurements and fieldwork of the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) physical activity and body composition validation study, and to determine the potential and limitations of the data obtained.

DESIGN

Multicentre validation study.

SUBJECTS

A total of 98 children from four different European countries (age: 4-10 years).

METHODS

An 8-day measurement protocol was carried out in all children using a collaborative protocol. Reference methods were the doubly labelled water method for physical activity, and a three- and a four-compartment model for body composition. Investigated field methods were accelerometers, a physical activity questionnaire and various anthropometric measurements.

RESULTS

For the validation of physical activity field methods, it was possible to gather data from 83 to 89 children, laying the basis for age- and sex-specific results. The validation of body composition field methods is possible in 64-80 children and allows sex-specific analyses but has only limited statistical power in the youngest age group (<6 years). The amount of activity energy expenditure (AEE) varied between centres, sexes and age groups, with boys and older children having higher estimates of AEE. After normalisation of AEE by body weight, most group-specific differences diminished, except for country-specific differences.

CONCLUSION

The IDEFICS validation study will allow age- and sex-specific investigation of questions pertaining to the validity of several field methods of body composition and physical activity, using established reference methods in four different European countries. From the participant analyses it can be concluded that the compliance for the investigated field methods was higher than that for the reference methods used in this validation study.

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.

Prevalence trends of obesity and overweight among 10-year-old children in western Sweden and relationship with parental body mass index

AIM

To determine the regional prevalence, secular and family-related trends of obesity and overweight among 10-y-old children.

METHODS

A cross-sectional study of 10-y-old children, born in 1990, was performed during September 2000 to June 2001 at school health centres in three communities in the western part of Sweden. Evaluation was performed in 6311 children, or 81% of the target population. Data from a cohort of children, born in 1974, who form the national growth charts, were available for comparison.

RESULTS

The mean body mass index was 17.9 kg/m2 in 10-y-old children born in 1990 and 17.0 kg/m2 for 10-y-olds born in 1974 (p < 0.0001). Of the 10-y-old children in 2000-2001, born in 1990, 18% were overweight and 2.9 % obese, which corresponds to a twofold increase in presence of overweight and a fourfold increase in presence of obesity among 10-y-old children from 1984 to 2000. There was a significant correlation between parental and child body mass index. The prevalence of obesity and being overweight appeared to be higher in children whose parents did not participate in the study.

CONCLUSION

During a 16-y period, from 1984 to 2000, a twofold increase in being overweight and a fourfold increase in obesity were seen among 10-y-old children in the western part of Sweden. Parental ponderosity or reluctance to participate in the study was related to a higher prevalence of being overweight or obese in the children. There is a need for the healthcare system to recognize the threats to the health of the population of this new "epidemic" and initiate preventive measures and treatment programmes.

Protective effect of breastfeeding against urinary tract infection

AIM

To assess the possible protective effect of exclusive breastfeeding against first-time febrile urinary tract infection (UTI) in children.

METHODS

Two children's hospitals and local child health centres in the Göteborg area, Sweden, participated in a prospective case-control study. In total, 200 consecutive cases (89M, 111F), aged 0-6y, presenting with first-time febrile UTI were enrolled. The mean +/- SD age was 0.98 +/- 1.15 y. As control subjects, 336 children (147M, 189F) were recruited from the child health centre of the case, matched for age and gender and included consecutively for each case during the first days after diagnosis. The duration of exclusive breastfeeding was obtained from the case and controls by a standardized procedure.

RESULTS

Ongoing exclusive breastfeeding gave a significantly lower risk of infection. A longer duration of breastfeeding gave a lower risk of infection after weaning, indicating a long-term mechanism. The protective role of breastfeeding was strongest directly after birth, then decreased until 7 mo of age, after which age no effect was demonstrated.

CONCLUSION

A protective role of breastfeeding against UTI was demonstrated. The study provides statistical support to the view that breast milk is a part of the natural defence against UTI.

Increased left ventricular mass in obese adolescents*1

AIMS

An increase of left ventricular mass (LVM) has been reported in obese adolescents in previous studies using echocardiography. The aim of our study was to determine the extent of the increase in LVM and correlation to other risk factors using cardiac magnetic resonance imaging in obese and lean adolescents.

METHODS AND RESULTS

Nineteen obese and 20 lean adolescents were recruited. Following resting blood pressure measurements and blood sampling for insulin, triglycerides, and cholesterol levels, all subjects underwent cardiac magnetic resonance examination to assess LVM. LVM adjusted for body height was 16% greater in obese compared to lean adolescents (median 66 g/m, p = 0.0042). Obese subjects had higher resting systolic blood pressures than controls (median 115 vs. 110 mmHg, p = 0.0077) and higher fasting triglyceride and insulin levels. HDL-cholesterol levels were lower in the obese group compared with the lean group.

CONCLUSIONS

Obese adolescents had a higher LVM than age-matched lean subjects, which correlated mainly with body mass index and systolic blood pressure. These findings add to the established cardiovascular risk profile of obese adolescents.

EHEC outbreak among staff at a children's hospital--use of PCR for verocytotoxin detection and PFGE for epidemiological investigation

This is the first report of a major foodborne outbreak of enterohaemorrhagic Escherichia coli (EHEC) in Sweden. It occurred among the nursing staff at a children's hospital with approximately 1600 employees. Contaminated lettuce was the most likely source of infection. Nine persons were culture-positive for Escherichia coli (E. coli) O157 and verocytotoxin-positive by PCR and a further two were verocytotoxin-positive by PCR only. All 11 EHEC-positive individuals had attended a party for approximately 250 staff members, which was held at the hospital. In a questionnaire 37 persons stated that they had symptoms consistent with EHEC infection during the weeks after the party. There was no evidence of secondary transmission from staff to patients. The value of PCR as a sensitive and fast method for diagnosis is discussed in this paper. Pulsed-field gel electrophoresis (PFGE) was used to ascertain that staff members were infected by the same clone, and that two patients with E. coli O157 infection were not.

Detrusor thickness in healthy children assessed by a standardized ultrasound method

PURPOSE

We determine the ultrasonographic detrusor thickness in healthy infants and children.

MATERIALS AND METHODS

We studied 150 healthy children, 79 boys and 71 girls, from newborns to 13 years old. The detrusor of the ventral and dorsal wall was measured with a previously established ultrasonographic technique, and the variation with age and bladder fullness was assessed.

RESULTS

Detrusor thickness varied significantly with the degree of bladder fullness (thinner at higher volumes). It also increased slightly with age. At bladder fullness of 10% or greater of expected bladder capacity (EBC), calculated using the formula EBC (ml.) = age (years) x 30 + 30, a practical upper limit for the detrusor thickness of the ventral wall at all ages was 2.0 mm. at a bladder fullness up to 50% of expected bladder capacity or 1.5 mm. at a higher degree of fullness. The detrusor of the ventral wall was slightly thicker in boys than in girls and also somewhat thicker than the detrusor of the dorsal wall.

CONCLUSIONS

The results indicate that ultrasonographic measurements of detrusor thickness in children may serve as a diagnostic tool and its usefulness in clinical as well as research work should be explored.

Renal concentrating capacity test using desmopressin at bedtime

A crossover trial was undertaken to evaluate the bedtime administration of desmopressin (Minirin) as a renal concentrating capacity test (RCCT). Medication was given intranasally as a single 20-microgram dose to 58 children ranging from 3 to 15 years of age with suspected or known renal impairment. The night-time test was shown to be a simple and effective means of assessing renal concentrating capacity. Comparison with the standard daytime test resulted in a 60 mosmol/kg higher mean osmolality in the night-time test. The results were reproducible, with a 95% confidence interval of -26 to 43 mosmol/kg. The procedure was easy to perform, with 51 of 52 patients (or their parents) preferring the night-time regimen compared with the daytime test. Night-time desmopressin therefore offers the potential of a user-friendly RCCT in patients with suspected impairment of renal tubular function.

Evaluation of a language-screening programme for 2.5-year-olds at Child Health Centres in Sweden

A population-based language-screening programme started in the western part of Sweden (South Bohuslän) in 1991, with the aim of identifying developmental language disability in 2.5-y-old children. The programme was evaluated during 1998 in an experimental study. A group of 105 2.5-y-old children was recruited from 24 separate Child Health Centres. A sample of 25 children with a positive screening result was selected. For each of the 25 children, 1-4 controls, i.e. children with a negative screening result, were selected. The results were reclassified blindly by three speech and language therapists and used as a gold standard. Positive and negative predictive values were estimated to be 0.52 (95% confidence interval 0.31-0.72) and 0.96 (95% confidence interval 0.89-0.99), respectively. Baye's theorem was used to calculate the sensitivity (0.69) and the specificity (0.93) of the screening. A method of calculating the sensitivity and specificity of the test method by means of three samples was demonstrated.

CONCLUSION

The data confirm that it is possible to identify reliably children with developmental language disability at 2.5 y of age through the screening programme.

Urinary tract infections in children below two years of age: a quality assurance project in Sweden. The Swedish Pediatric Nephrology Association

The objective of this study was to evaluate the basis for diagnosis and assessment of children <2 y of age with urinary tract infections (UTI) and to describe their subsequent management as currently practised in Sweden. The study was a prospective, multicentre project as part of a programme for quality assurance. A total of 2309 children (1111M, 1198F) was studied during a 2-y period. Of the population at risk, 1.6% of both boys and girls were diagnosed with a UTI. This represents a minimum figure. Suprapubic bladder aspiration was mainly used during the first year of life, with the highest frequency in the youngest infants. Adhesive bags were used in half of the children, and the frequency increased with age. Imaging of the urinary tract was performed in 97% of the children. Vesicoureteric reflux was the most common finding, occurring in 36% of the girls and 24% of the boys. The presence of dilatation of the upper urinary tract correlated significantly to the presence and grade of reflux. Initial intravenous therapy was given to 31% of the children and long-term antibacterial prophylaxis to 20%. Major differences were found between centres in diagnostic rate, urine sampling technique and the use of parenteral therapy. In conclusion, this study showed a high diagnostic rate of urinary infections in children below 2 y of age. The urine sampling technique was optimal (suprapubic aspiration) in half of the infants, but less reliable in the children above 1 y of age. The frequency of imaging investigations of the urinary tract was high. The strategies for diagnosis and treatment varied considerably among centres.

Incidence rate of first-time symptomatic urinary tract infection in children under 6 years of age

A retrospective population-based study was performed to describe the incidence rate of first time symptomatic urinary tract infection in children under 6 y of age. A total number of 299 children was identified during the 20-month study period in a population of 20,000 girls and 21,000 boys. The cumulative incidence rate during the first 6 y of life was 6.6% for girls and 1.8% for boys. The annual incidence rate in girls of urinary tract infection/1000 at risk was between 9 and 14 for each of the six 1-y age intervals. In girls, the proportion of febrile urinary tract infection was high during the infant year, while girls older than 2 y most often had non-febrile infection. For infant boys, the incidence rate and the proportion of febrile urinary tract infection were comparable to that of girls, while after the first year of life urinary infection of any kind was rare, with an incidence rate of 1-2/1000 at risk.

Interleukin (IL)-6 and IL-8 in children with febrile urinary tract infection and asymptomatic bacteriuria

Urine and serum interleukin (IL)-6 and IL-8 responses were higher in children with febrile urinary tract infection (n = 61) than in those with asymptomatic bacteriuria (n = 39). By univariate analysis, cytokine levels were related to age, sex, reflux, renal scarring, urine leukocytes, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and bacterial properties (P fimbriae but not hemolysin). Multivariate modeling showed that urine IL-6 responses were higher in girls than boys, increased with age, and were positively associated with CRP, ESR, serum IL-6, and urine leukocyte counts. The urine IL-8 response was not influenced by age, but it was influenced by P fimbriae and was associated with ESR, CRP, urine leukocytes, and female sex. The results show that cytokine responses to urinary tract infection vary with the severity of infection and that cytokine activation is influenced by a variety of host and bacterial variables.

Intestinal carriage of P fimbriated Escherichia coli and the susceptibility to urinary tract infection in young children

This prospective study analyzed the intestinal carriage of P fimbriated Escherichia coli as a host susceptibility factor in urinary tract infection (UTI). P fimbriation was defined by the pap and G adhesin (papG1A2, prsGJ96) genotypes. Children with UTI carried pap+ E. coli in the fecal flora more often than healthy controls both at diagnosis (86% vs. 29%) and during infection-free intervals (approximately 40%; P < .01). P1 blood group-positive children carried pap+ E. coli in the fecal flora more often (88%) than those with P2 blood group (40%; P < .05). A pap+ E. coli strain caused UTI in 53 of 55 patients who carried both pap+ and pap- strains in their fecal flora. These results suggest that persons who develop UTI have an increased tendency to carry pap+ E. coli in the large intestine and that these pap+ E. coli cause UTI more often than pap E. coli strains in the fecal flora of the same host.

Involvement of maternity and health care staff in breast-feeding

The prerequisites of the staff for their interest and concern in working with questions related to breast-feeding have been studied by questionnaires which were answered by 133 nurses at pregnancy care centres, child health centres and maternity wards. The intention was to identify possible obstacles for the staff in supporting the mother's breast-feeding. In spite of extensive experience and positive attitudes to breast-feeding, about half of the staff found it difficult to work with these questions and to give enough support. The most common reasons for this fact were insufficient knowledge about breast-feeding, few possibilities for further training and a heavy workload. It was also evident that some routines need to be corrected. For instance, information about breast-feeding was provided late during pregnancy, the fathers were infrequently engaged and the communication between the departments was limited. A reorganization of the staff's working routines and their continuous further training in issues related to breast-feeding are recommended.

A survey of Swedish mothers' view on breastfeeding and experiences of social and professional support

The purpose of this cross-sectional study was to investigate conditions for breastfeeding among 452 mothers. Three different groups of women, participating in the Swedish health care system, were asked to complete a questionnaire about breastfeeding and related issues: 1) pregnant women attending the pregnancy care centres (n = 186), 2) women staying at the maternity wards after delivery (n = 171) and 3) women with two-month-old child attending the child health stations (n = 95). We found that the majority of the mothers were in favour of breastfeeding and intended to or had begun to breastfeed their infants. The main problems were "sore nipples", "children who cannot take the breast" and "insufficient milk production". Negative experiences of previous breastfeeding and overwhelming demands were motives for weaning. The personnel within the health care system were shown to be important for the mothers as regards advice and support. However, we found that certain routines could be revised to strengthen the mothers' attitude towards breastfeeding: 1) information on and discussions about breastfeeding occurred infrequently at the pregnancy care centres. 2) Water or formulated milk was often given to the newborn baby at the maternity wards and 3) the participation of the fathers was limited. Continuous surveillance of the routines and education of the health care staff would be desirable to enable them to give the mothers the right breastfeeding support and advice at the right time.

Reference values for renal concentrating capacity in children by the desmopressin test

Reference values are reported for maximal renal concentrating capacity in children using intranasally administered desmopressin. The report is based on 591 tests in 473 healthy children aged 0.5-13 years. The concentrating capacity increased markedly during the first years of life and reached a plateau at the age of 3 years. The mean value minus two standard deviations was 525 mosmol/kg at 1 year of age and 825 mosmol/kg at 3 years of age.

Medical histories of children with acute pyelonephritis compared with controls

The medical history of infants and preschool children with their first known episode of pyelonephritis was obtained by questionnaire and compared with that of controls matched for age, sex and living area. Previous infection, medical consultation and antibiotic treatment were registered significantly more often in the patients. Furthermore a high proportion of cases had recently received antibiotic therapy, primarily penicillin V. Urinary tract infections were reported more often among first degree relatives of the cases. Exclusive breast-feeding was significantly shorter in the pyelonephritis patients, according both to the questionnaire and to the records from the Child Health Centers. The two populations were not shown to differ in birth weight or length, neonatal history, number of hospitalizations, previous episodes of fever or frequency of atopic disease in the families.

Special virulence of the Escherichia coli O1:K1:H7 clone in acute pyelonephritis

The relationship between acute-phase responses and bacterial properties was studied in a population of 88 children with their first known episode of acute pyelonephritis. One strain from each patient was included in the study. Eighty-four of the patients were infected with Escherichia coli, which was assigned a clonotype according to the O:K:H stereotype; 55 patients carried one of the 12 multiply occurring clones. Globotetraosylceramide-specific (globo+) adhesion was present in 90% of these 12 clones, compared with 62% in the remaining 29 singly occurring clones. The patients infected with globo+ strains had significantly increased inflammatory reactions compared with patients with globo- strains. The O1:K1:H7 strain was the single most frequent clone (n = 14) that always expressed globo+ adhesins. Patients infected with O1:K1:H7 had an inflammatory response similar to that of other globo+ infections, but had a shorter duration of symptoms before diagnosis, higher fever, and higher peripheral leukocyte count. These results demonstrate special virulence of the O1:K1:H7 clone, reflected by the acuteness of onset of infection.

Voiding cystourethrography as a predictor of reflux nephropathy in children with urinary-tract infection

Most children who develop renal damage (scarring) after urinary-tract infection have vesicoureteral reflux. Voiding cystourethrography is therefore usually recommended as the initial radiologic study in children with urinary-tract infection. However, renal damage may occur also in the absence of reflux. The aim of this investigation was to determine the sensitivity and predictive value of reflux during voiding cystourethrography in identifying children at risk for renal damage. Eighty-four consecutive children, 2 months to 6 years old, with nonobstructive, first-known, febrile urinary-tract infection underwent voiding cystourethrography and urography. Twenty-seven (32%) had reflux and 10 (12%) had or developed renal damage. Two of the children and four of the kidneys with renal damage had no reflux at initial examination. The sensitivity of reflux as a marker for renal damage was 80%, specificity was 74%, positive predictive value was 30%, and negative predictive value was 96%. Thus, most children who develop renal damage after urinary-tract infection have reflux during voiding cystourethrography. However, there is a risk, albeit small, for renal damage to occur in the absence of reflux.

Fever, bacteriuria and concomitant disease in children with urinary tract infection

A total of 124 children aged 0.2 to 6 years were enrolled in a study of first time febrile urinary tract infection. The patient population was stratified in groups according to the stringency of criteria for fever and bacteriuria and the presence of concomitant disease. The major group of 88 patients consisted of children with fever greater than or equal to 38.5 degrees C measured at the hospital within 24 hours of diagnosis, bacteriuria verified by suprapubic bladder aspiration or repeated cultures of voided urine, but without concomitant disease. These children were mainly infected with attaching Escherichia coli specific for galactose alpha (1----4) beta galactose containing receptors and had laboratory evidence of inflammation. Another group of 11 children were distinguished with strictly defined bacteriuria and concomitant disease. These children were infected with nonattaching bacteria and had lower concentrations of C-reactive protein in serum and lower microsedimentation rates than the major group. Five of these children had a reduction in renal concentrating capacity. The study emphasizes the heterogeneity among patients with fever and bacteriuria but does not rule out the possibility of renal involvement in any subgroup.

Bacterial virulence and inflammatory response in infants with febrile urinary tract infection or screening bacteriuria

Two populations were analyzed prospectively after a first episode of urinary tract infection. Asymptomatic infants were screened at 2 weeks and at 3 and 10 months of age, and bacteriuria was confirmed by bladder puncture. Infants with febrile urinary tract infection were enrolled during the same study period. The inflammatory response was characterized by the presence of fever, serum C-reactive protein, microsedimentation rate, urinary leukocyte excretion, and width of the ureters. The bacteria were defined for O:K:H serotype, hemolysin production, resistance to the bactericidal effect of serum, attachment to uroepithelial cells, and specificity for the globoseries of glycolipid receptors. In agreement with previous studies, the frequency of increased inflammatory signs and of attaching Escherichia coli was significantly higher in infants with febrile urinary tract infection than in the screening group. Within both patient groups, however, children infected with attaching E. coli strains had significantly more inflammatory signs. The results suggest that adherence facilitates the presentation of bacterial components capable of causing inflammation in the tissues in the urinary tract.

Ureteral dilatation in children with febrile urinary tract infection or bacteriuria

Little information is available on the relationship between urinary infection in children and infants, with or without vesicoureteral reflux, and dilatation of the urinary tract. The purpose of this study was to determine the effects of infection and reflux on the diameter of the ureter at excretory urography in children with acute, febrile urinary tract infections and in infants with bacteriuria found at screening. Standardized measurements of ureteral diameter were obtained for 79 children (2 months to 6 years old) with urinary tract infections and for 45 infants with bacteriuria. Patients with urinary tract obstruction or malformations were excluded. Seventy-one children with febrile urinary tract infection had ureteral visualization that allowed measurements. Ureteral diameter in this group was significantly wider than in a reference group, and 42 children (59%) had ureteral diameters that were more than 2 standard deviations above the normal mean. Ureteral diameter at excretory urography increased with increasing grades of reflux, but dilatation occurred also in the absence of reflux. Twenty-two of the 45 infants in the group with bacteriuria had sufficient ureteral visualization for measurements. The ureters in this group were wider than in the reference group, and eight infants had ureteral diameters that were more than 2 standard deviations above the normal mean. We conclude that ureteral dilatation is a common effect of acute urinary tract infection and bacteriuria in children.

Urinary immunoglobulins in healthy individuals and children with acute pyelonephritis

Urine samples obtained from children with acute pyelonephritis and from healthy children and adults were analysed with regard to the molecular form and specific antibody activity of urinary immunoglobulins. The urinary IgA and IgG levels were quantified in unconcentrated urine by radioimmunoassay. The children with urinary tract infection had significantly higher levels of IgG and IgA than age-matched controls but not higher than healthy adults. After tenfold concentration, the urine was fractionated on an Ultrogel AcA 22 column, and the IgA, secretory IgA, and IgG in the fractions were determined by radioimmunoassay. IgA in urine from healthy adults was predominantly represented by polymeric IgA linked to secretory component; small quantities of monomeric IgA were also present. IgG eluted in the position of the serum standard. Increased proportions of IgG and monomeric IgA were found in the infected patients. Specific antibody activity of the IgG and IgA classes to antigens of the infecting Escherichia coli strain was detected in whole and in fractionated urine from children with acute pyelonephritis. The specific antibody activity in healthy adults and children was low.

Antibody responses to impurities of penicillin in infants and rabbits

Antibody responses to penicilloyl were recorded in infants and children treated for about 1 week with intravenous ampicillin. In this single-blind, randomized study two commercially available preparations were compared, one of high-grade purity (less than 0.1 microgram antigen per gram) and the other slightly contaminated with high molecular weight proteinaceous material (1.5 microgram antigen per gram) according to a radioimmunoassay. The results showed no significant increase in the antibody titers in any of the patient groups. The immunogenic properties of high molecular weight proteinaceous impurities isolated from phenoxymethyl penicillin during manufacture were tested in rabbits given daily subcutaneous injections with 0.1-10 micrograms of the antigen over 10 day periods. When the 10-day period was repeated, the rabbits injected with more than 2 micrograms of antigen responded with both IgM/IgG and IgE antibodies. The clinical as well as the animal study indicates that antigen impurities in the preparations of the order of 2 micrograms per gram or less do not elicit a significant antibody response. However, the study in rabbits demonstrates that high molecular weight impurities can induce penicillin allergy if present in about 10-fold higher quantities than those usually found in the commercial penicillin preparations of today.