Individually customised fetal weight charts derived from ultrasound measurements: the Generation R Study

Maternal and fetal characteristics are important determinants of fetal growth potential, and should ideally be taken into consideration when evaluating fetal growth variation. We developed a model for individually customised growth charts for estimated fetal weight, which takes into account physiological maternal and fetal characteristics known at the start of pregnancy. We used fetal ultrasound data of 8,162 pregnant women participating in the Generation R Study, a prospective, population-based cohort study from early pregnancy onwards. A repeated measurements regression model was constructed, using backward selection procedures for identifying relevant maternal and fetal characteristics. The final model for estimating expected fetal weight included gestational age, fetal sex, parity, ethnicity, maternal age, height and weight. Using this model, we developed individually customised growth charts, and their corresponding standard deviations, for fetal weight from 18 weeks onwards. Of the total of 495 fetuses who were classified as small size for gestational age (<10th percentile) when fetal weight was evaluated using the normal population growth chart, 80 (16%) were in the normal range when individually customised growth charts were used. 550 fetuses were classified as small size for gestational age using individually customised growth charts, and 135 of them (25%) were classified as normal if the unadjusted reference chart was used. In conclusion, this is the first study using ultrasound measurements in a large population-based study to fit a model to construct individually customised growth charts, taking into account physiological maternal and fetal characteristics. These charts might be useful for use in epidemiological studies and in clinical practice.

The health impact of social disadvantage in early childhood; the Generation R study

Inequalities in child health are of major concern to policymakers, public health specialists and clinicians. This review of studies within the context of the Generation R study illustrates that inequalities in population health, at least partly, originate in pregnancy and early childhood. The review shows inequalities with regard to the health of the pregnant mother, with regard to the growth of the fetus, with regard to birth outcomes, and with regard to health indicators in early childhood. These results are shown with regard to both biological/somatic outcomes, as well as with regard to psychosocial outcomes and healthy lifestyles. Both socioeconomic inequalities and ethnic inequalities in health are present. Although some inequalities can be explained by known determinants, research needs to be done to reach a full understanding of the pathways between social disadvantage and ill health in early childhood.

Exhaled nitric oxide and the risk of wheezing in infancy: the Generation R Study

We assessed whether exhaled nitric oxide fraction (F(eNO)), a marker of eosinophilic airway inflammation, at 6 months was associated with the risk of wheezing during the first 2 yrs of life. In the Generation R birth cohort, pre- and post-natal risk factors for respiratory morbidity and respiratory symptoms were assessed by questionnaires at 6 and 24 months. In 428 infants, off-line mixed oral/nasal F(eNO) was successfully measured during tidal breathing at 6 months. Complete data on F(eNO) and respiratory symptoms within the first 6 months of life were available for 294 infants. F(eNO) was higher in males, was positively associated with age and was negatively associated with upper and lower respiratory symptoms within the first 6 months. Logistic regression analysis showed that for every ppb increase of F(eNO) measured at 6 months, infants had a 1.06 (95% confidence interval 1.01-1.11)-fold increased risk of wheezing in the second year of life. High F(eNO) (>17.5 ppb) showed a limited added value in predicting wheezing in the second year. We conclude that F(eNO) at 6 months is positively associated with the risk of wheezing, but has limited added value in predicting wheezing in the second year of life in individual children.

Streptococcus pneumoniae exposure is associated with human metapneumovirus seroconversion and increased susceptibility to in vitro HMPV infection

It remains largely unknown which factors determine the clinical outcome of human metapneumovirus (HMPV) infections. The aim of the present study was to analyse whether exposure to bacterial pathogens can influence HMPV infections. From 57 children, serum samples and colonization data for Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and Streptococcus pneumoniae were collected at 1.5, 6, 14 and 24 months of age. Seroconversion rates to HMPV were determined and related to bacterial carriage. Frequent nasopharyngeal carriage (≥2 times in the first 2 years of life) of S. pneumoniae, but not of the other three pathogens, was associated with increased seroconversion rates of infants to HMPV at the age of 2 years (frequently vs. less exposed, 93% vs. 59%; p <0.05). Subsequently, the susceptibility of well-differentiated normal human bronchial epithelial cells (wd-NHBE) pre-incubated with bacterial pathogens to in vitro HMPV infection was evaluated. Pre-incubation of wd-NHBE with S. pneumoniae resulted in increased susceptibility to infection with HMPV-enhanced green fluorescent protein (EGFP), as determined by enumeration of EGFP-positive cells. This was not the case for cells pre-incubated with H. influenzae, M. catarrhalis on S. aureus. We conclude that exposure to S. pneumoniae can modulate HMPV infection.

Can urgency classification of the Manchester triage system predict serious bacterial infections in febrile children?

OBJECTIVE

To evaluate the discriminative ability of the Manchester triage system (MTS) to identify serious bacterial infections (SBIs) in children with fever in the emergency department (ED) and to study the association between predictors of SBI and discriminators of MTS urgency of care.

METHODS

This prospective observational study included 1255 children with fever (1 month-16 years) attending the ED of the Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands in 2008-9. Triage urgency was determined with the MTS (urgency (U) level 1-5). The relationship between triage urgency and SBI was assessed with multivariable logistic regression, including effects of age, sex and temperature. Discriminative ability was assessed by receiver operating characteristic curve analysis.

RESULTS

SBI prevalence was 11% (n=131, 95% CI 9% to 12%). The discriminative value of the MTS for predicting SBI was 0.57 (95% CI 0.52 to 0.62), and the MTS did not contribute to a model including age, sex and temperature. The sensitivity of the MTS (U1-2 vs U3-5) to detect SBI was 0.42 (95% CI 0.33 to 0.51) and specificity was 0.69 (95% CI 0.66 to 0.72). MTS high urgency discriminators include several known predictors of SBI, such as fever, work of breathing, meningism and oxygen saturation, but apply to non-SBI children as well.

CONCLUSION

The MTS has poor discriminative ability to predict the presence of SBIs in children presenting with fever to the paediatric ED. Important predictors of SBI are represented within the MTS, but are used in a different way to classify urgency.

Duration and exclusiveness of breastfeeding and childhood asthma-related symptoms

The aim of our study was to examine the associations of breastfeeding duration and exclusiveness with the risks of asthma-related symptoms in preschool children, and to explore whether these associations are explained by atopic or infectious mechanisms. This study was embedded in a population-based prospective cohort study of 5,368 children. Information on breastfeeding duration, exclusiveness and asthma-related symptoms, including wheezing, shortness of breath, dry cough and persistent phlegm, was obtained by questionnaires. Compared with children who were breastfed for 6 months, those who were never breastfed had overall increased risks of wheezing, shortness of breath, dry cough and persistent phlegm during the first 4 yrs (OR 1.44 (95% CI 1.24-1.66), 1.26 (1.07-1.48), 1.25 (1.08-1.44) and 1.57 (1.29-1.91), respectively). Similar associations were observed for exclusive breastfeeding. The strongest associations per symptom per year were observed for wheezing at 1 and 2 yrs. Additionally adjusted analyses showed that the associations of breastfeeding with asthma-related symptoms were not explained by eczema but partly by lower respiratory tract infections. Shorter duration and nonexclusivity of breastfeeding were associated with increased risks of asthma-related symptoms in preschool children. These associations seemed, at least partly, to be explained by infectious, but not by atopic, mechanisms.

Undertriage in the Manchester triage system: an assessment of severity and options for improvement

BACKGROUND

The Manchester Triage System (MTS) determines an inappropriately low level of urgency (undertriage) to a minority of children. The aim of the study was to assess the clinical severity of undertriaged patients in the MTS and to define the determinants of undertriage.

METHODS

Patients who had attended the emergency department (ED) were triaged according to the MTS. Undertriage was defined as a 'low urgent' classification (levels 3, 4 and 5) under the MTS; as a 'high urgent' classification (levels 1 and 2) under an independent reference standard based on abnormal vital signs (level 1), potentially life-threatening conditions (level 2), and a combination of resource use, hospitalisation, and follow-up for the three lowest urgency levels. In an expert meeting, three experienced paediatricians used a standardised format to determine the clinical severity. The clinical severity had been expressed by possible consequences of treatment delay caused by undertriage, such as the use of more interventions and diagnostics, longer hospitalisation, complications, morbidity, and mortality. In a prospective observational study we used logistic regression analysis to assess predictors for undertriage.

RESULTS

In total, 0.9% (119/13,408) of the patients were undertriaged. In 53% (63/119) of these patients, experts considered undertriage as clinically severe. In 89% (56/63) of these patients the high reference urgency was determined on the basis of abnormal vital signs. The prospective observational study showed undertriage was more likely in infants (especially those younger than three months), and in children assigned to the MTS 'unwell child' flowchart (adjusted OR<3 months 4.2, 95% CI 2.3 to 7.7 and adjusted ORunwell child 11.1, 95% CI 5.5 to 22.3).

CONCLUSION

Undertriage is infrequent, but can have serious clinical consequences. To reduce significant undertriage, the authors recommend a systematic assessment of vital signs in all children.

The introduction of allergenic foods and the development of reported wheezing and eczema in childhood: the Generation R study

OBJECTIVE

To examine whether the timing of introduction of the allergenic foods cow's milk, hen's egg, peanuts, tree nuts, soy, and gluten is associated with eczema and wheezing in children 4 years of age or younger.

DESIGN

Population-based prospective cohort study from fetal life until young adulthood.

SETTING

Rotterdam, the Netherlands, from April 2002 through January 2006.

PARTICIPANTS

A total of 6905 preschool children participating in the Generation R study.

MAIN EXPOSURE

Timing of introduction of cow's milk, hen's egg, peanuts, tree nuts, soy, and gluten collected by questionnaires at 6 and 12 months of age.

MAIN OUTCOME MEASURES

Information on the outcomes eczema and wheezing were obtained by questions from the age-adapted version of the "International Study of Asthma and Allergies in Childhood" core questionnaire and questionnaire data on parentally reported physician diagnosis for eczema.

RESULTS

Of 6905 children, wheezing was reported in 31% at age 2 years and in 14% at ages 3 and 4 years. Eczema was reported in 38%, 20%, and 18% of children at the ages of 2, 3, and 4 years, respectively. The introduction of cow's milk, hen's egg, peanuts, tree nuts, soy, and gluten before the age of 6 months was not significantly associated with eczema or wheezing at any age after adjustment for potential confounders (P > .10 for all comparisons). The results did not alter after stratification according to the child's history of cow's milk allergy and parental history of atopy.

CONCLUSION

This study does not support the recommendation for delayed introduction of allergenic foods after age 6 months for the prevention of eczema and wheezing.

Validity of telephone and physical triage in emergency care: the Netherlands Triage System

BACKGROUND

Due to emergency care overcrowding, right care at the right place and time is necessary. Uniform triage of patients contacting different emergency care settings will improve quality of care and communication between health care providers.

OBJECTIVE

Validation of the computer-based Netherlands Triage System (NTS) developed for physical triage at emergency departments (EDs) and telephone triage at general practitioner cooperatives (GPCs).

METHODS

Prospective observational study with patients attending the ED of a university-affiliated hospital (September 2008 to November 2008) or contacting an urban GPC (December 2008 to February 2009). For validation of the NTS, we defined surrogate urgency markers as best proxies for true urgency. For physical triage (ED): resource use, hospitalization and follow-up. For telephone triage (GPC): referral to ED, self-care advice after telephone consultation or GP advice after physical consultation. Associations between NTS urgency levels and surrogate urgency markers were evaluated using chi-square tests for trend.

RESULTS

We included nearly 10 000 patients. For physical triage at ED, NTS urgency levels were associated with resource use, hospitalization and follow-up. For telephone triage at GPC, trends towards more ED referrals in high NTS urgency levels and more self-care advices after telephone consultation in lower NTS urgency levels were found. The association between NTS urgency classification and GP advice was less explicit. Similar results were found for children; however, we found no association between NTS urgency level and GP advice.

CONCLUSIONS

Physically and telephone-assigned NTS urgency levels were associated with majority of surrogate urgency markers. The NTS as single triage system for physical and telephone triage seems feasible.

Safety of the Manchester Triage System to identify less urgent patients in paediatric emergence care: a prospective observational study

OBJECTIVE

To assess hospitalisation rate as a proxy for the ability of the Manchester Triage System (MTS) to identify less urgent paediatric patients. We also evaluated general practitioner (GP) services to determine if they met patients' needs compared to emergency department care.

METHODS

Self-referred children triaged as less urgent by the MTS in two emergency departments in the Netherlands were included in a prospective observational study. Therapeutic interventions during emergency department consultation, hospitalisation after consultation and determinants for hospitalisation were assessed using logistic regression analysis.

RESULTS

During emergency department consultation, extensive therapeutic interventions were performed more often in patients with extremity problems (n=175, 19%) and dyspnoea (n=30, 15%). 191 (3.5%) of 5425 patients were hospitalised. Age and presenting problem remained statistically significant in multivariable logistic analysis, predicting hospitalisation with ORs of 3.0 (95% CI 2.2 to 4.1) for age <1 year, 2.5 (1.5 to 4.1) for dyspnoea, 3.5 (2.5 to 4.9) for gastrointestinal problems and 2.8 (1.1 to 7.2) for patients with fever without identified source compared to all other patients. 3975 (76%) of 5234 patients were contacted for follow-up after discharge. Six (0.15%) patients were hospitalised after emergency department discharge.

CONCLUSION

In the MTS less urgent categories, overall hospitalisation is low, although children <1 year of age or with dyspnoea, gastrointestinal problems or fever without identified source have an increased risk for hospitalisation. Except for these patient groups, the MTS identifies less urgent patients safely. It may not be optimal for GP services to treat patients with extremity problems.

Motor learning in children with neurofibromatosis type I

The aim of this study was to quantify the frequently observed problems in motor control in Neurofibromatosis type 1 (NF1) using three tasks on motor performance and motor learning. A group of 70 children with NF1 was compared to age-matched controls. As expected, NF1 children showed substantial problems in visuo-motor integration (Beery VMI). Prism-induced hand movement adaptation seemed to be mildly affected. However, no significant impairments in the accuracy of simple eye or hand movements were observed. Also, saccadic eye movement adaptation, a cerebellum dependent task, appeared normal. These results suggest that the motor problems of children with NF1 in daily life are unlikely to originate solely from impairments in motor learning. Our findings, therefore, do not support a general dysfunction of the cerebellum in children with NF1.

Maternal smoking during pregnancy, fetal arterial resistance adaptations and cardiovascular function in childhood

OBJECTIVE

To unravel the mechanisms underlying the previously demonstrated associations between low birthweight and cardiovascular disease in adulthood, we examined whether maternal smoking during pregnancy leads to fetal arterial resistance adaptations, and subsequently to fetal growth retardation and changes in postnatal blood pressure and cardiac development.

DESIGN

Prospective cohort study from early fetal life onwards.

SETTING

Academic hospital.

POPULATION

Analyses were based on 1120 children aged 2 years.

METHODS

Maternal smoking during pregnancy [non-smoking, first trimester smoking, continued smoking (< 5 and ≥ 5 cigarettes/day)] was assessed by questionnaire.

MAIN OUTCOME MEASURES

Third trimester placental and fetal arterial resistance indices and fetal growth were assessed by ultrasound and Doppler measurements. Postnatal blood pressure and cardiac structures (aortic root diameter, left atrial diameter, left ventricular mass) were measured at 2 years of age.

RESULTS

First trimester smoking was not associated with third trimester placental and fetal blood flow adaptations. Continued smoking of ≥ 5 cigarettes/day was associated with an increased resistance in uterine, umbilical and middle cerebral arteries, and with a decreased flow and diameter of the ascending aorta. Among mothers who continued to smoke, the third trimester estimated fetal weights and birthweights were most affected in children with the highest umbilical artery resistance. Fetal arterial resistance indices were also associated with aortic root diameter and left atrial diameter.

CONCLUSIONS

Fetal arterial resistance adaptations may be involved in the pathways leading from maternal smoking during pregnancy to low birthweight and cardiovascular developmental changes in childhood in the offspring.

Readiness to transfer to adult care of adolescents with chronic conditions: exploration of associated factors

PURPOSE

To explore associations between adolescents' perception of their readiness to transfer to adult care and socio-demographic and disease-related characteristics, effect of the condition, self-management ability, and attitude toward transition.

METHODS

A cross-sectional study was conducted in a Dutch university hospital, where all adolescents (12-19 years) with somatic chronic conditions (n = 3,648) were invited to participate in a web-based questionnaire. Invitations were issued to those without an intellectual disability and who had been under treatment for at least 3 years.

RESULTS

In all, 30% (n = 1,087) of the adolescents responded; 954 assessed their perception of readiness for transfer. The majority (56%) felt that they were ready for transfer. Logistic regression analyses showed that 48% of the total variance in transfer readiness (TR) could be explained. Feeling more self-efficacious in skills for independent hospital visits and a greater perceived independence during consultations were found to be most strongly associated with being ready to transfer. Higher TR was associated with older age, but age did not prove to be the most important explaining variable. Adolescents with a more positive attitude toward transition and those who reported more discussions related to future transfer also felt more ready. Disease-related factors and effect of the condition including quality of life were only weakly associated with higher TR.

CONCLUSIONS

Adolescents' attitude to transition and their level of self-efficacy in managing self-care seem to be the keystones to TR. This study suggests that individual transition plans and readiness assessments might prove to be beneficial. Strengthening adolescents' independence and self-management competencies, combined with early preparation and repeated discussions on transition, seem to be useful strategies to increase adolescents' readiness for transfer to adult care.

Foetal and postnatal growth and bone mass at 6 months: the Generation R Study

OBJECTIVE

To examine whether parental, foetal and postnatal characteristics and growth patterns in foetal life and infancy are associated with bone mass at 6 months, as bone acquisition seems to be associated with genetic and environmental factors.

DESIGN

This study was embedded in the Generation R Study, a prospective cohort from early foetal life onwards.

PATIENTS AND MEASUREMENTS

Bone mineral density (BMD) and bone mineral content (BMC) total body (TB) and BMD lumbar spine (LS) were measured by dual-energy X-ray absorptiometry in 252 infants at 6 months. Parental, foetal and postnatal data were collected by physical and foetal ultrasound examinations and questionnaires.

RESULTS

Maternal, foetal and postnatal anthropometrics were positively associated with BMD(TB) and BMC(TB) at 6 months, but only postnatal anthropometrics were associated with BMD(LS) . A gain in weight-SD-score during foetal life and prenatal catch-up in weight were positively associated with BMD(TB) . After birth, a gain in weight-SD-score was positively associated with BMD(LS) and bone mineral apparent density (BMAD(LS) ). The effect was strongest between 6 weeks and 6 months. Catch-up in weight was associated with a lower probability of low (lowest quartile of) BMD(TB) and BMD(LS) . Children remaining in the first tertile of weight from birth to 6 months had a much higher risk of low BMD(TB) at 6 months [OR (95% CI): 15 (2, 88)].

CONCLUSIONS

Our findings suggest that growth patterns in foetal and postnatal life are associated with bone mass in infancy and may have consequences for bone mass in later life. Follow-up studies are needed to assess whether and to what extent maternal anthropometrics, foetal and postnatal growth patterns have an effect on bone status in adulthood.

Detection of child abuse in emergency departments: a multi-centre study

OBJECTIVE

This study examines the detection rates of suspected child abuse in the emergency departments of seven Dutch hospitals complying and not complying with screening guidelines for child abuse.

DESIGN

Data on demographics, diagnosis and suspected child abuse were collected for all children aged ≤18 years who visited the emergency departments over a 6-month period. The completion of a checklist of warning signs of child abuse in at least 10% of the emergency department visits was considered to be compliance with screening guidelines.

RESULTS

A total of 24 472 visits were analysed, 54% of which took place in an emergency department complying with screening guidelines. Child abuse was suspected in 52 children (0.2%). In 40 (77%) of these 52 cases, a checklist of warning signs had been completed compared with a completion rate of 19% in the total sample. In hospitals complying with screening guidelines for child abuse, the detection rate was higher (0.3%) than in those not complying (0.1%, p<0.001).

CONCLUSION

During a 6-month period, emergency department staff suspected child abuse in 0.2% of all children visiting the emergency department of seven Dutch hospitals. The numbers of suspected abuse cases detected were low, but an increase is likely if uniform screening guidelines are widely implemented.

Glutamine-enriched enteral nutrition in very low birthweight infants and allergic and infectious diseases at 6 years of age

In a previous randomised controlled trial, we found that glutamine-enriched enteral nutrition in 102 very low birthweight (VLBW) infants decreased both the incidence of serious infections in the neonatal period and the risk of atopic dermatitis during the first year of life. We hypothesised that glutamine-enriched enteral nutrition in VLBW infants in the neonatal period influences the risk of allergic and infectious disease at 6 years of age. Eighty-eight of the 102 infants were eligible for the follow-up study (13 died, 1 chromosomal abnormality). Doctor-diagnosed allergic and infectious diseases were assessed by means of validated questionnaires. The association between glutamine-enriched enteral nutrition in the neonatal period and allergic and infectious diseases at 6 years of age was based on univariable and multivariable logistic regression analyses. Seventy-six of the 89 (85%) infants participated, 38 in the original glutamine-supplemented group and 38 in the control group. After adjustment, we found a decreased risk of atopic dermatitis in the glutamine-supplemented group: adjusted odds ratio (aOR) 0.23 [95% CI 0.06, 0.95]. No association between glutamine supplementation and hay fever, recurrent wheeze and asthma was found. A decreased risk of gastrointestinal tract infections was found in the glutamine-supplemented group (aOR) 0.10 [95% CI 0.01, 0.93], but there was no association with upper respiratory, lower respiratory or urinary tract infections. We concluded that glutamine-enriched enteral nutrition in the neonatal period in VLBW infants decreased the risk of atopic dermatitis and gastrointestinal tract infections at 6 years of age.

Is there an association between wheezing and constipation in preschool children? Explanations from a longitudinal birth cohort

OBJECTIVE

To assess whether wheezing and atopic dermatitis were associated with constipation in preschool children and to what extent shared risk factors contribute to this relationship.

METHODS

A population-based sample of 4651 preschool children was used. At the age of 24, 36 and 48 months, a parental report of functional constipation was available according to the Rome II criteria, and data on atopic dermatitis and wheezing were available using age-adapted questionnaires from the International Study of Asthma and Allergies in Childhood. Stepwise multivariate analyses were performed to assess whether body mass index, infection exposure, food allergy and infant nutrition, and parental stress explained the association between wheezing, atopic dermatitis and constipation.

RESULTS

Out of 4651 children, 12-17% had functional constipation between 24 and 48 months. Symptoms of wheezing decreased from 20% to 12% and atopic dermatitis decreased from 30% to 18% at the age of 24 and 48 months respectively. Between the age of 24 and 48 months, wheezing symptoms were significantly associated with functional constipation (OR 1.17; 1.02 to 1.34) but these results were mainly explained by the child's exposure to infections and use of antibiotics (adjusted odds ratio 1.08; 95% CI 0.95 to 1.24). No significant association was found between symptoms of atopic dermatitis and functional constipation (OR 1.08; 95% CI 0.94 to 1.23).

CONCLUSIONS

These findings suggest that functional constipation coexists with wheezing in childhood but is mainly explained by the child's infection exposure and use of antibiotics. Therefore, an independent association between respiratory symptoms and functional bowel disorders as suggested in previous studies is questionable.

No association of obesity gene FTO with body composition at the age of 6 months. The Generation R Study

BACKGROUND

Genome-wide association studies on body mass index (BMI) have identified an FTO polymorphism (rs9939609) as having the strongest effect.

AIM

We examined the effect of FTO genotype on body composition at the age of 6 months using skinfold thickness measurements and dual energy X-ray absorptiometry (DXA).

MATERIAL/SUBJECTS AND METHODS

This study was embedded in a population-based prospective cohort study from early fetal life onwards. FTO genotype was related to anthropometric measurements (weight and height), subcutaneous fat mass measured by skinfold thickness, and total, truncal, and peripheral fat mass and lean mass measured by DXA. Analyses for skinfold thickness and DXA were performed in 695 and 216 children, respectively.

RESULTS

Genotype frequency was TT 40.3%, TA 45.5%, and AA 14.2%. No significant differences between FTO genotypes were found in weight, height or BMI. Furthermore, FTO genotype was not associated with any skinfold thickness. Finally, no associations between FTO genotype and body composition measures (fat and lean mass) assessed by DXA were found.

CONCLUSIONS

We observed no association between this FTO polymorphism and body composition at the age of 6 months. Longer follow-up studies are necessary to examine at which age and by which mechanisms FTO genotype starts to influence fat mass and body composition.

Health-related quality of life in preschool children in five health conditions

Objective

To test the responsiveness of the Infant/Toddler Quality of Life Questionnaire (ITQOL) to five health conditions. In addition, to evaluate the impact of the child’s age and gender on the ITQOL domain scores.

Methods

Observational study of 494 Dutch preschool-aged children with five clinical conditions and 410 healthy preschool children randomly sampled from the general population. The clinical conditions included neurofibromatosis type 1, wheezing illness, bronchiolitis, functional abdominal complaints, and burns. Health-related quality of life (HRQoL) was assessed by a mailed parent-completed ITQOL. Mean ITQOL scale scores for all conditions were compared with scores obtained from the reference sample. The effect of patient’s age and gender on ITQOL scores was assessed using multi-variable regression analysis.

Results

In all health conditions, substantially lower scores were found for several ITQOL scales. The conditions had a variable effect on the type of ITQOL domains and a different magnitude of effect. Scores for ‘physical functioning’, ‘bodily pain’, and ‘general health perceptions’ showed the greatest range. Parental impact scales were equally affected by all conditions. In addition to disease type, the child’s age and gender had an impact on HRQoL.

Conclusions

The five health conditions (each with a distinct clinical profile) affected the ITQOL scales differently. These results indicate that the ITQOL is sensitive to specific characteristics and symptom expression of the childhood health conditions investigated. This insight into the sensitivity of the ITQOL to health conditions with different symptom expression may help in the interpretation of HRQoL results in future applications.

The Generation R Study: design and cohort update 2010

The Generation R Study is a population-based prospective cohort study from fetal life until young adulthood. The study is designed to identify early environmental and genetic causes of normal and abnormal growth, development and health during fetal life, childhood and adulthood. The study focuses on four primary areas of research: (1) growth and physical development; (2) behavioural and cognitive development; (3) diseases in childhood; and (4) health and healthcare for pregnant women and children. In total, 9,778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. General follow-up rates until the age of 4 years exceed 75%. Data collection in mothers, fathers and preschool children included questionnaires, detailed physical and ultrasound examinations, behavioural observations, and biological samples. A genome wide association screen is available in the participating children. Regular detailed hands on assessment are performed from the age of 5 years onwards. Eventually, results forthcoming from the Generation R Study have to contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

Colonization of healthy children by Moraxella catarrhalis is characterized by genotype heterogeneity, virulence gene diversity and co-colonization with Haemophilus influenzae

The colonization dynamics of Moraxella catarrhalis were studied in a population comprising 1079 healthy children living in Rotterdam, The Netherlands (the Generation R Focus cohort). A total of 2751 nasal swabs were obtained during four clinic visits timed to take place at 1.5, 6, 14 and 24 months of age, yielding a total of 709 M. catarrhalis and 621 Haemophilus influenzae isolates. Between January 2004 and December 2006, approximate but regular 6-monthly cycles of colonization were observed, with peak colonization incidences occurring in the autumn/winter for M. catarrhalis, and winter/spring for H. influenzae. Co-colonization was significantly more likely than single-species colonization with either M. catarrhalis or H. influenzae, with genotypic analysis revealing no clonality for co-colonizing or single colonizers of either bacterial species. This finding is especially relevant considering the recent discovery of the importance of H. influenzae-M. catarrhalis quorum sensing in biofilm formation and host clearance. Bacterial genotype heterogeneity was maintained over the 3-year period of the study, even within this relatively localized geographical region, and there was no association of genotypes with either season or year of isolation. Furthermore, chronological and genotypic diversity in three immunologically important M. catarrhalis virulence genes (uspA1, uspA2 and hag/mid) was also observed. This study indicates that genotypic variation is a key factor contributing to the success of M. catarrhalis colonization of healthy children in the first years of life. Furthermore, variation in immunologically relevant virulence genes within colonizing populations, and even within genotypically identical M. catarrhalis isolates, may be a result of immune evasion by this pathogen. Finally, the factors facilitating M. catarrhalis and H. influenzae co-colonization need to be further investigated.

Breastfeeding protects against infectious diseases during infancy in industrialized countries. A systematic review

Firstly, this review was performed to assess the effect of breastfeeding on infections during infancy in industrialized countries. Secondly, the effect of duration and exclusiveness of breastfeeding were explored. Studies were identified using Medline, Cochrane Library, Science Citation Index and by a manual search from bibliographies of articles from August 1986 to January 2008. Follow-up, case-control and randomized controlled trial (RCT) studies performed in an industrialized country, published in English, with breastfeeding as a determinant, with overall infections, gastrointestinal or respiratory tract infections as a major outcome, and at least 40 participants in the study were included. Using Bauchner's criteria published in a review in 1986, two reviewers and a peer reviewer assessed the internal validity of those studies. Twenty-one studies that met the inclusion and internal validity criteria were included. These included 16 follow-up and four case-control studies and one RCT. Four out of five studies observed decreased effects on overall infections in breastfed infants. With regard to gastrointestinal infections, six out of eight studies suggested that breastfeeding had a protective effect. Thirteen out of 16 studies concluded that breastfeeding protects infants against respiratory tract infections. Five studies combined duration and exclusiveness of breastfeeding. All studies observed a protective dose/duration-response effect on gastrointestinal or respiratory tract infections. These studies strongly suggest that breastfeeding protects infants against overall infections, gastrointestinal and respiratory tract infections in industrialized countries. The optimal duration of exclusive breastfeeding for protection against infectious diseases needs to be studied in more detail.

Early detection and counselling intervention of asthma symptoms in preschool children: study design of a cluster randomised controlled trial

BACKGROUND

Prevention of childhood asthma is an important public health objective. This study evaluates the effectiveness of early detection of preschool children with asthma symptoms, followed by a counselling intervention at preventive child health centres. Early detection and counselling is expected to reduce the prevalence of asthma symptoms and improve health-related quality of life at age 6 years.

METHODS/DESIGN

This cluster randomised controlled trial was embedded within the Rotterdam population-based prospective cohort study Generation R in which 7893 children (born between April 2002 and January 2006) participated in the postnatal phase. Sixteen child health centres are involved, randomised into 8 intervention and 8 control centres. Since June 2005, an early detection tool has been applied at age 14, 24, 36 and 45 months at the intervention centres. Children who met the intervention criteria received counselling intervention (personal advice to parents to prevent smoke exposure of the child, and/or referral to the general practitioner or asthma nurse). The primary outcome was asthma diagnosis at age 6 years. Secondary outcomes included frequency and severity of asthma symptoms, health-related quality of life, fractional exhaled nitric oxide and airway resistance at age 6 years. Analysis was according to the intention-to-treat principle. Data collection will be completed end 2011.

DISCUSSION

This study among preschool children provides insight into the effectiveness of early detection of asthma symptoms followed by a counselling intervention at preventive child health centres.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN15790308.

Risk factors for otitis media in children with special emphasis on the role of colonization with bacterial airway pathogens: the Generation R study

Acute otitis media is the most frequent diagnosis in children visiting physicians’ offices. Risk factors for otitis media have been widely studied. Yet, the correlation between bacterial carriage and the development of otitis media is not entirely clear. Our aim was to study in a population-based prospective cohort the risk factors for otitis media in the second year of life with special emphasis on the role of colonization with Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. The study was embedded in the Generation R Study. Data on risk factors and doctor-diagnosed otitis media were obtained by midwives, hospital registries and postal questionnaires in the whole cohort (n = 7,295). Nasopharyngeal swabs were obtained at the age of 1.5, 6 and 14 months in the focus cohort (n = 1,079). Of these children, 2,515 (47.2%) suffered at least one period of otitis media in their second year of life. The occurrence of otitis media during the follow-up period in the first 6 months of life and between 6 and 12 months of age was associated with the risk of otitis media in the second year of life (aOR, 1.83 95% CI 1.24–2.71 and aOR 2.72, 95% CI 2.18–3.38, respectively). Having siblings was associated with an increased risk for otitis media in the second year of life (aOR 1.42, 95% CI 1.13–1.79). No associations were found between bacterial carriage in the first year of life and otitis media in the second year of life. In our study, otitis media in the first year of life is an independent risk factor for otitis media in the second year of life. Surprisingly, bacterial carriage in the first year of life did not add to this risk. Moreover, no association was observed between bacterial carriage in the first year of life and otitis in the second year of life.

Prolonged and exclusive breastfeeding reduces the risk of infectious diseases in infancy

OBJECTIVE

To examine the associations of duration of exclusive breastfeeding with infections in the upper respiratory (URTI), lower respiratory (LRTI), and gastrointestinal tracts (GI) in infancy.

METHODS

This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life onward in the Netherlands. Rates of breastfeeding during the first 6 months (never; partial for <4 months, not thereafter; partial for 4-6 months; exclusive for 4 months, not thereafter; exclusive for 4 months, partial thereafter; and exclusive for 6 months) and doctor-attended infections in the URTI, LRTI, and GI until the age of 12 months were assessed by questionnaires and available for 4164 subjects.

RESULTS

Compared with never-breastfed infants, those who were breastfed exclusively until the age of 4 months and partially thereafter had lower risks of infections in the URTI, LRTI, and GI until the age of 6 months (adjusted odds ratio [aOR]: 0.65 [95% confidence interval (CI): 0.51-0.83]; aOR: 0.50 [CI: 0.32-0.79]; and aOR: 0.41 [CI: 0.26-0.64], respectively) and of LRTI infections between the ages of 7 and 12 months (aOR: 0.46 [CI: 0.31-0.69]). Similar tendencies were observed for infants who were exclusively breastfed for 6 months or longer. Partial breastfeeding, even for 6 months, did not result in significantly lower risks of these infections.

CONCLUSIONS

Exclusive breastfeeding until the age of 4 months and partially thereafter was associated with a significant reduction of respiratory and gastrointestinal morbidity in infants. Our findings support health-policy strategies to promote exclusive breastfeeding for at least 4 months, but preferably 6 months, in industrialized countries.

Passive immunisation against respiratory syncytial virus: a cost-effectiveness analysis

AIM

The cost-effectiveness of passive immunisation against respiratory syncytial virus (RSV) in the Netherlands was studied by assessing incremental costs to prevent one hospitalisation in high-risk children using a novel individualised monthly approach.

METHODS

Cost-effectiveness analysis was performed by combining estimates of individual hospitalisation costs and monthly hospitalisation risks, with immunisation costs, parental costs and efficacy of passive immunisation for a reference case with the highest hospitalisation risks and costs of hospitalisation during the RSV season (male, gestational age < or =28 weeks, birth weight < or =2500 g, having bronchopulmonary dysplasia (BPD), aged 0 months at the beginning of the season (October)). Various sensitivity analyses and a cost-neutrality analysis were performed.

RESULTS

Cost-effectiveness of passive immunisation varied widely by child characteristics and seasonal month. For the reference case it was most cost effective in December at euro13,190 per hospitalisation averted. Cost-effectiveness was most sensitive to changes in hospitalisation risk. For the reference case, cost neutrality was reached in December, if acquisition costs of passive immunisation decreased from euro 930 to euro 375, monthly hospitalisation risk increased from 7.6% to 17%, or hospitalisation costs increased from euro 10 250 to euro 23 250 per hospitalisation. Even if passive immunisation prevented all hospitalisations, costs per hospitalisation averted in December would still exceed euro 2645.

CONCLUSIONS

Although cost-effectiveness of passive immunisation varied strongly by child characteristics and seasonal month, incremental costs per hospitalisation averted were always high. A restrictive immunisation policy only immunising children with BPD in high-risk months is therefore recommended. The costs of passive immunisation would have to be considerably reduced to achieve cost-effectiveness.

Functional abdominal complaints in pre-school children: parental reports of health-related quality of life

Purpose

The aim of this study is to assess the influence of functional abdominal complaints (FAC) on health-related quality of life in a group of Dutch pre-school children.

Methods

Parents of children aged up to 6.0  visiting the outpatient pediatric department, Erasmus MC-Sophia, Rotterdam, The Netherlands in the period January 2005–December 2006 for functional abdominal complaints during at least 3 months were asked to complete the Infant/Toddler Quality of life Questionnaire (ITQOL), and questions of the abdominal pain index for use by parents to report pain symptoms in pre-school children. ITQOL scale scores of children with FAC were compared against with Dutch reference values. The abdominal pain index was tested for internal consistency and test–retest reliability. Correlations between ITQOL scale scores and abdominal pain index were assessed by Spearman’s rank test.

Results

Results are based on 81 questionnaires completed by parents of children with FAC (response rate 61%). Children had a median age of 46 months (interquartile range 27–59), 48% girls. A significant impact was observed on most aspects of quality of life, particularly for physical functioning, general development, bodily pain, temperament and moods, general health perceptions and parental emotional impact. Parents of children with functional constipation tended to report lower scores than those of children with other FAC. The abdominal pain index appeared to be valid and was significantly correlated with ITQOL scales bodily pain and general health perceptions.

Conclusions

A substantial lower health-related quality of life is reported in pre-school children with functional abdominal complaints, with effects on physical, emotional and parental domains. The 5-question severity index of abdominal pain appeared a valid tool and may be helpful to quickly assess the severity of abdominal pain in clinical practice.

Mother's educational level and fetal growth: the genesis of health inequalities

BACKGROUND

Women of low socio-economic status (SES) give birth to lighter babies. It is unknown from which moment during pregnancy socio-economic differences in fetal weight can be observed, whether low SES equally affects different fetal-growth components, or what the effect of low SES is after taking into account mediating factors.

METHODS

In 3545 pregnant women participating in the Generation R Study, we studied the association of maternal educational level (high, mid-high, mid-low and low) as a measure of SES with fetal weight, head circumference, abdominal circumference and femur length. We did this before and after adjusting for potential mediators, including maternal height, pre-pregnancy body mass index and smoking.

RESULTS

In fetuses of low-educated women relative to those of high-educated women, fetal growth was slower, leading to a lower fetal weight that was observable from late pregnancy onwards. In these fetuses, growth of the head [-0.16 mm/week; 95% confidence interval (CI): -0.25 to -0.07; P = 0.0004], abdomen (-0.10 mm/week; 95% CI: -0.21 to 0.01; P = 0.08) and femur (-0.03 mm/week; 95% CI: -0.05 to -0.006; P = 0.01) were all slower; from mid-pregnancy onwards, head circumference was smaller, and from late pregnancy onwards, femur length was also smaller. The negative effect of low education was greatest for head circumference (difference in standard deviation score in late pregnancy: -0.26; 95% CI: -0.36 to -0.15; P < 0.0001). This effect persevered even after adjustment for the potential mediators (adjusted difference: -0.14; 95% CI: -0.25 to -0.03; P = 0.01).

CONCLUSIONS

Low maternal education is associated with a slower fetal growth and this effect appears stronger for growth of the head than for other body parts.

Kidney growth curves in healthy children from the third trimester of pregnancy until the age of two years. The Generation R Study

Information about growth of kidney structures in early life is limited. In a population-based prospective cohort study, from foetal life onwards, we constructed reference curves for kidney growth from the third trimester of pregnancy until early childhood, using data from 1,158 healthy children. Kidney size, defined as length, width, depth and volume, was measured in the third trimester of pregnancy and at the postnatal ages of 6 months and 24 months. Analyses were based on more than 2,500 kidney measurements. In the third trimester of pregnancy and at 6 months of age all kidney measurements were larger in boys than in girls. At 24 months of age, these gender differences were only significant for left kidney structures and right kidney length. Both groups showed trends towards smaller left kidney measurements than right kidney measurements at all ages. Gender-specific reference curves based on post-conceptional and postnatal ages were constructed for left and right kidney length, width, depth and volume. We concluded that kidney size is influenced by age and gender. Left kidney size tended to be smaller than right kidney size, except for kidney length. The reference curves can be used for assessing kidney structures by ultrasound in foetal life and early childhood.

Employment status and the risk of pregnancy complications: the Generation R Study

OBJECTIVES

This study explored the relationships of employment status, type of unemployment and number of weekly working hours, with a wide range of pregnancy outcomes.

METHODS

Information on employment characteristics and pregnancy outcomes was available for 6111 pregnant women enrolled in a population-based cohort study in the Netherlands.

RESULTS

After adjustment for confounders, there were no statistically significant differences in risks of pregnancy complications between employed and unemployed women. Among unemployed women, women receiving disability benefit had an increased risk of preterm ruptured membranes (OR 3.16, 95% CI 1.49 to 6.70), elective caesarean section (OR 2.98, 95% CI 1.21 to 7.34) and preterm birth (OR 2.64, 95% CI 1.32 to 5.28) compared to housewives. Offspring of students and women receiving disability benefit had a significantly lower mean birth weight than offspring of housewives (difference: -93, 95% CI -174 to -12; and -97, 95% CI -190 to -5, respectively). In employed women, long working hours (>or=40 h/week) were associated with a decrease of 45 g in offspring's mean birth weight (adjusted analysis; 95% CI -89 to -1) compared with 1-24 h/weekly working hours.

CONCLUSIONS

We found no indications that paid employment during pregnancy effects the health of the mother and child. However, among unemployed and employed women, women receiving disability benefit, students and women with long working hours during pregnancy were at risk for some adverse pregnancy outcomes. More research is needed to replicate these results and explain these findings. Meanwhile, prenatal care providers should be made aware of the risks associated with specific types of unemployment and long working hours.

Induction of antibodies by Staphylococcus aureus nasal colonization in young children

In order to develop novel antistaphylococcal strategies, understanding the determinants of carriage and how humans respond to Staphylococcus aureus exposure is essential. Here, the primary S. aureus-specific humoral immune response and its association with nasal colonization was studied in young children. Sera from 57 colonized or non-colonized children, serially collected at birth and at 6, 14 and 24 months, were analysed for IgG, IgA and IgM binding to 19 staphylococcal proteins, using flow cytometry-based technology. The antibody responses showed extensive inter-individual variability. On average, the levels of antistaphylococcal IgA and IgM increased from birth until the age of 2 years (p <0.05), whereas the levels of IgG decreased (p <0.001). Placentally transferred maternal IgG did not protect against colonization. In colonized children, IgG and IgA levels for a number of proteins were higher than in non-colonized children. At both 14 and 24 months, the levels of IgG against chemotaxis inhibitory protein of S. aureus (at 24 months; median fluorescence intensity, 4928 vs. 24, p <0.05), extracellular fibrinogen-binding protein (987 vs. 604, p <0.05), and iron-responsive surface determinant H (62 vs. 5, p <0.05) were significantly higher in colonized children. The levels of IgA against CHIPS, IsdH and IsdA were higher (p <0.05). Therefore, CHIPS, Efb, IsdA and IsdH seem to play a role in nasal colonization of young children.

Role of Staphylococcus aureus nasal colonization in atopic dermatitis in infants: the Generation R Study

OBJECTIVE

To study the association between Staphylococcus aureus nasal colonization and atopic dermatitis (AD) in infancy.

DESIGN

Population-based prospective cohort study of pregnant women and their children.

SETTING

This project was embedded in the Generation R Study.

PARTICIPANTS

A total of 1079 postnatal Dutch infants/children participated in the focus cohort. Main Exposures Nasal swabs for S aureus cultivation were taken at ages 1.5, 6, and 14 months. Main Outcome Measure Questionnaires that pertain to AD and confounders (birth weight, gestational age, sex, and parental eczema) were completed prenatally and postnatally. The outcome was AD in the first and second years of life.

RESULTS

A first positive culture for S aureus at age 6 months was associated with AD prevalence in the first and second years of life (adjusted odds ratio [aOR], 2.13; 95% confidence interval [CI], 1.17-3.87; and aOR, 2.88; 95% CI, 1.60-5.19, respectively) and also with severity (aOR, 3.27; 95% CI, 1.30-8.03). Moreover, frequent colonization in the first year of life (>/=2 times) held a 4.29-fold (95% CI, 1.03- to 17.88-fold) risk of moderate to severe AD in the second year of life.

CONCLUSION

Colonization with S aureus at age 6 months and frequent colonization in the first year of life are associated with AD and its severity in young children.

Type 2 diabetes gene TCF7L2 polymorphism is not associated with fetal and postnatal growth in two birth cohort studies

Background

An inverse association between birth weight and the risk of developing type 2 diabetes (T2D) in adulthood has been reported. This association may be explained by common genetic variants related to insulin secretion and resistance, since insulin is the most important growth factor in fetal life. The objective of this study was to examine whether T2D gene polymorphism TCF7L2 rs7903146 is associated with growth patterns from fetal life until infancy.

Methods

This study was performed in two independent birth cohort studies, one prospective population-based (Generation R), and one of subjects born small-for-gestational-age (SGA cohort). Fetal growth was assessed by ultrasounds in second and third trimesters of pregnancy in Generation R. Growth in infancy was assessed in both cohorts at birth and at 6, 12 and 24 months postnatally. TCF7L2 genotype was determined in 3,419 subjects in Generation R and in 566 subjects in the SGA cohort.

Results

Minor allele frequency did not differ significantly (p = 0.47) between Generation R (T-allele: 28.7%) and the SGA cohort (T-allele: 29.8%). No differences at birth were found in gestational age or size (head circumference, length, weight) between the genotypes in either cohort. TCF7L2 genotype was also not associated with any pre- or postnatal growth characteristic in either Generation R or the SGA cohort.

Conclusion

We found no evidence for an association between TCF7L2 genotype and fetal and early postnatal growth. Furthermore, this TCF7L2 polymorphism was not associated with an increased risk of SGA.

Validating and updating a prediction rule for neurological sequelae after childhood bacterial meningitis

Recently, a prediction rule for developing neurological sequelae after childhood bacterial meningitis was developed on a small derivation set. Before implementing in practice a prediction rule must first be tested in new patients (external validation). Our aim was to study the external validity of this rule and, if necessary, to update the rule. The prediction rule was tested on newly available data (validation set) by assessing the rule's calibration and discrimination. We updated the prediction rule by adding extra predictors and re-estimating the regression coefficients of the original predictors in the combined datasets. The rule showed poor agreement between predicted risks and observed frequencies. The ROC area was 0.65 (95% CI 0.57-0.72), which was statistically significantly lower than in the derivation set (0.87 (0.78-0.96)), p-value<0.01. The updated prediction rule showed adequate performance in the combined data sets; the ROC area was 0.77 (95% CI 0.72-0.82). Further study of the generalizability of this updated rule may stimulate application in clinical practice.

Are starting and continuing breastfeeding related to educational background? The generation R study

OBJECTIVE

To assess the effect of a woman's educational level on starting and continuing breastfeeding and to assess the role of sociodemographic, lifestyle-related, psychosocial, and birth characteristics in this association.

METHODS

We used the data of 2914 participants in a population-based prospective cohort study. Information on educational level, breastfeeding, sociodemographic (maternal age, single parenthood, parity, job status), lifestyle-related (BMI, smoking, alcohol use), psychosocial (whether the pregnancy was planned, stress), and birth (gestational age, birth weight, cesarean delivery, place and type of delivery) characteristics were obtained between pregnancy and 12 months postpartum. Odds ratios and 95% confidence intervals of starting and continuing breastfeeding for educational level were obtained by logistic regression, adjusted for each group of covariates and for all covariates simultaneously.

RESULTS

Of 1031 highest-educated mothers, 985 (95.5%) started breastfeeding; the percentage was 73.1% (255 of 349) in the lowest-educated mothers. At 6 months, 39.3% (405 of 1031) of highest-educated mothers and 15.2% (53 of 349) of lowest-educated mothers were still breastfeeding. Educationally related differences were present in starting breastfeeding and the continuation of breastfeeding until 2 months but not in breastfeeding continuation between 2 and 6 months. Lifestyle-related and birth characteristics attenuated the association between educational level and breastfeeding, but the association was hardly affected by sociodemographic and psychosocial characteristics.

CONCLUSIONS

Decisions to breastfeed were underlain by differences in educational background. The underlying pathways require further research. For the time being, interventions on promoting breastfeeding should start early in pregnancy and should increase their focus on low-educated women.

Explaining educational inequalities in birthweight: the Generation R Study

Although low socio-economic status has consistently been associated with lower birthweight, little is known about the factors whereby socio-economic disadvantage influences birthweight. We therefore examined explanatory mechanisms that may underlie the association between the educational level of pregnant women, as an indicator of socio-economic status, and birthweight. The study was embedded within a population-based cohort study in the Netherlands. Information on maternal education, offspring's birthweight and several determinants of birthweight was available for 3546 pregnant women of Dutch origin. Infants of the lowest educated women had a statistically significantly lower birthweight than infants of the highest educated women [difference adjusted for gender and gestational age: -123 g (95% CI -167, -79)]. Parity, age of the pregnant women, hypertension, parental height and parental birthweight, marital status, pregnancy planning, financial concerns, number of people in household, weight gain and smoking habits individually explained part of the differences in birthweight, while adjustment for working hours and body mass index resulted in increases in birthweight differences between the educational levels. After full adjustment, the difference in birthweight between lowest and highest education was reduced by 66%. Our study confirmed remarkable educational inequalities in birthweight, a large part of which was explained by pregnancy characteristics, anthropometrics, the psychosocial and material situation, and lifestyle-related factors. Altering smoking habits may be an option to reduce educational differences in birthweight, as many lower-educated women tend to continue smoking during pregnancy. In order to tackle inequalities in birthweight, it is important that interventions are accessible for pregnant women in lower socio-economic strata.

Breast-feeding modifies the association of PPARgamma2 polymorphism Pro12Ala with growth in early life: the Generation R Study

OBJECTIVE

We examined whether the PPARgamma2 Ala12 allele influences growth in early life and whether this association is modified by breast-feeding.

RESEARCH DESIGN AND METHODS

This study was embedded in the Generation R Study, a prospective cohort study from early fetal life onward. PPARgamma2 was genotyped in DNA obtained from cord blood samples in 3,432 children. Information about breast-feeding was available from questionnaires. Weight, head circumference, and femur length were repeatedly measured in second and third trimesters of pregnancy, at birth, and at the ages of 1.5, 6, 11, 14, and 18 months.

RESULTS

Genotype frequency distribution was 77.6% (Pro12Pro), 20.7% (Pro12Ala), and 1.7% (Ala12Ala). Growth rates in weight from second trimester of pregnancy to 18 months were higher for Pro12Ala and Ala12Ala than for Pro12Pro carriers (differences 1.11 g/week [95% CI 0.47-1.74] and 2.65 g/week [0.45-4.87], respectively). We found an interaction between genotype and breast-feeding duration (P value for interaction <0.0001). In infants who were breast-fed for > or =4 months, PPARgamma2 Pro12Ala was not associated with growth rate. When breast-feeding duration was <2 months or 2-4 months, growth rate was higher in Ala12Ala than Pro12Pro carriers (differences 9.80 g/week [3.97-15.63] and 6.32 g/week [-1.04 to 13.68], respectively).

CONCLUSIONS

The PPARgamma2 Ala12 allele is associated with an increased growth rate in early life. This effect may be influenced by breast-feeding duration. Further studies should replicate these findings, identify the underlying mechanisms, and assess whether these effects persist into later life.

Health-related quality of life in children with neurofibromatosis type 1: contribution of demographic factors, disease-related factors, and behavior

OBJECTIVE

To investigate health-related quality of life (HR-QOL) in children with neurofibromatosis type 1 (NF1) with parental reports and children's self-reports, and to investigate the potential contribution of demographic factors, disease-specific factors, and problems in school performance or behavior.

STUDY DESIGN

In a prospective observational study, parents of 58 children with NF1 (32 boys, 26 girls, age 12.2 +/- 2.5 years) visiting a university clinic, and their 43 children 10 years or older were assessed with the Child Health Questionnaire (CHQ). Potential determinants of domain scores were assessed in 3 explorative regression models.

RESULTS

Parents reported a significant impact of NF1 on 9/13 CHQ scales, with moderate effect sizes on 8 (general health perceptions, physical functioning, general behavior, mental health, self esteem, family activities, role functioning emotional/behavioral, and parent emotional impact). Children report an impact on bodily pain, and an above average general behavior. Multiple CHQ scales were sensitive to demographic factors and behavioral problems, and 1 to NF1 severity. NF1 visibility and school problems did not influence HR-QOL.

CONCLUSIONS

Parents, but not the children with NF1, report a profound impact of NF1 on physical, social, behavioral, and emotional aspects of HR-QOL. Multiple HR-QOL domains were most sensitive to behavioral problems, which points to an exciting potential opportunity to improve HR-QOL in children with NF1 by addressing these behavioral problems.

Fetal growth influences lymphocyte subset counts at birth: the Generation R Study

BACKGROUND

Preterm born and low-birth-weight infants are at risk for severe infections in infancy. It has been suggested that these infants have an immature immune system.

OBJECTIVE

To assess the associations of gestational age, birth weight and fetal growth with absolute lymphocyte subset counts at birth.

METHODS

This study was conducted in 571 infants participating in the Generation R Study, a population-based prospective cohort study from fetal life onwards. Gestational age and birth weight were obtained from midwives and hospital registries. Fetal growth was defined as increase in weight between late pregnancy and birth. Lymphocytes and T lymphocyte subset counts in cord blood were determined by 6-color flow cytometry. Multivariate linear regression models with adjustment for gender, maternal education, smoking, alcohol use, fever and mode of delivery were applied.

RESULTS

Per week increase of gestational age, T, B and NK lymphocyte counts increased with 3, 5 and 6%, respectively (p < 0.05). Helper, cytotoxic and naive T lymphocyte counts increased with 3, 4 and 5%, respectively (p < 0.05), but memory T lymphocyte counts did not. Increased birth weight and fetal growth were significantly associated with higher B lymphocyte counts, independent of gestational age, but not with the other lymphocyte subset counts.

CONCLUSIONS

Lymphocyte subset counts increase with prolonged gestation, suggesting an ongoing development of the immune system. Birth weight and fetal growth seem to influence only B lymphocyte counts.

Variation in the IGF-1 gene is associated with lymphocyte subset counts in neonates: the Generation R Study

OBJECTIVE

IGF-1 stimulates growth, development and function of lymphocytes. The aim of this study was to examine whether functional variants of the IGF-1 gene are associated with absolute lymphocyte subset counts in neonates.

STUDY DESIGN AND MEASUREMENTS

This study was embedded in the Generation R Study, a prospective cohort study from foetal life onwards. A polymorphism in the IGF-1 promoter region was genotyped in cord blood DNA. Lymphocytes (T, B and NK) and T lymphocyte subsets (helper, cytotoxic, naive and memory) in cord blood were immunophenotyped in 380 neonates by six-colour flow cytometry.

RESULTS

In total, 39% of the neonates were homozygous for the 192-bp allele (wild-type), 48% were heterozygous and 13% were noncarrier. No differences in absolute lymphocyte and T lymphocyte subset counts were observed between the 192-bp allele heterozygous and homozygous groups. In noncarriers, we found 15% lower T lymphocyte (P = 0.03), 22% lower B lymphocyte (P = 0.04) and 10% lower NK lymphocyte counts (P = 0.36) than in the 192-bp allele homozygous group. Analyses of T lymphocyte subsets showed 16% lower helper T lymphocyte counts (P = 0.01) in noncarriers. No significant differences were found for cytotoxic, naive and memory T lymphocyte counts. All associations were adjusted for gravidity, mode of delivery, gestational age, birth weight, gender and 1- and 5- min Apgar scores.

CONCLUSIONS

Our study showed associations between this IGF-1 promoter region polymorphism and absolute lymphocyte subset counts in neonates. These results should be regarded as hypothesis generating until they have been replicated in other studies.

[The practice guideline 'Children with fever' (second revision) from the Dutch College of General Practitioners; a response from the perspective of paediatricians]

The new version of the practice guideline 'Children with fever' was recently published by the Dutch College of General Practitioners and is commented on from the perspective of paediatricians. Whether or not general practitioners should refer feverish children to the paediatrician depends on the age of the patient and the severity of the illness. All children younger than 1 month and children with warning symptoms should be referred to a paediatrician at once. One of the warning symptoms is that the child gives the impression of being seriously ill at the physical examination. As it can be difficult to ascertain the severity of the illness and to distinguish which children will develop a serious bacterial infection, observation scales can be of use, as can the general practitioner's intuitive feeling that 'something is wrong'. Emphasis is put on the fact that infections are dynamic processes and therefore good follow-up is important. Children under the age of 2 years with a fever with no apparent cause should be re-examined after 24-48 h. Parents should be properly instructed to come back for re-examination of their child if the clinical picture changes or worsens.

Factors associated with pneumococcal carriage in healthy Dutch infants: the generation R study

OBJECTIVE

To study the prevalence, risk factors, and dynamics of pneumococcal carriage in infancy.

STUDY DESIGN

In a population-based prospective cohort study conducted in Rotterdam, the Netherlands between June 2003 and November 2006, nasopharyngeal swabs were obtained from children at age of 1.5, 6, and 14 months. Data on risk factors were obtained from midwives, hospital registries, and questionnaires.

RESULTS

The prevalence of pneumococcal carriage increased from 8.3% at age 1.5 months (n = 627) to 31.3% at age 6 months (n = 832) and 44.5% at age 14 months (n = 757). The prevalence of serotypes covered by the 7-valent conjugate increased from 3.0% to 16.2% and 27.7% at these respective ages. Having siblings (adjusted odds ratio [aOR] = 4.33; 95% confidence interval [CI] = 1.22 to 15.35) and day care attendance (aOR = 3.05, 95% CI = 1.88 to 4.95 at 6 months; aOR = 2.78, 95% CI 1.= 70 to 4.55 at 14 months) were associated with pneumococcal carriage. Pneumococcal carriage at age 6 months was associated with pneumococcal carriage at age 14 months (aOR = 2.43; 95% CI = 1.50 to 3.94). Pneumococcal carriage was not associated with sex, maternal smoking, maternal educational level, or breast-feeding.

CONCLUSIONS

The prevalence of serotypes covered by the 7-valent conjugate vaccine increased in the first year of life. Siblings, day care attendance, and previous pneumococcal carriage were independent factors associated with pneumococcal carriage.

A variant of the IGF-I gene is associated with blood pressure but not with left heart dimensions at the age of 2 years: the Generation R Study

BACKGROUND AND OBJECTIVE

A common variant of the IGF-I gene has been shown to be associated with cardiovascular disease in adulthood. The objective of this study was to examine whether this variant of the IGF-I gene is associated with blood pressure and left heart dimensions in early childhood.

RESEARCH DESIGN AND METHODS

This study was embedded in the Generation R Study, a population-based prospective cohort study from foetal life onwards. IGF-I promoter region was genotyped in DNA obtained from cord blood. Blood pressure (systolic and diastolic) and echocardiography (left ventricular mass, left atrial diameter and aortic root diameter) measurements were performed at the age of 2 years. Analyses were performed in 538 subjects.

RESULTS

Eight alleles of the IGF-I promoter region were identified. In total, 43% of the subjects were homozygous for the 192 bp allele (wild type), 46% were heterozygous and 11% were non-carriers. Significantly lower systolic and diastolic blood pressures were found in non-carrier subjects (difference compared with homozygous subjects: -4.4 (95% confidence interval (CI) -7.8 to -1.1) mmHg and -3.5 (95% CI: -6.9 to -0.1) mm respectively). No significant differences were found for left heart dimensions at the age of 2 years. No association was found when we used a previously proposed alternative classification of the IGF-I gene.

CONCLUSION

The variant type of the IGF-I promoter region is associated with lower blood pressure but not with left heart dimensions at the age of 2 years. Follow-up studies are needed to examine whether these differences persist in later life.

Effect of simvastatin on cognitive functioning in children with neurofibromatosis type 1: a randomized controlled trial

CONTEXT

Neurofibromatosis type 1 (NF1) is among the most common genetic disorders that cause learning disabilities. Recently, it was shown that statin-mediated inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase restores the cognitive deficits in an NF1 mouse model.

OBJECTIVE

To determine the effect of simvastatin on neuropsychological, neurophysiological, and neuroradiological outcome measures in children with NF1.

DESIGN, SETTING, AND PARTICIPANTS

Sixty-two of 114 eligible children (54%) with NF1 participated in a randomized, double-blind, placebo-controlled trial conducted between January 20, 2006, and February 8, 2007, at an NF1 referral center at a Dutch university hospital.

INTERVENTION

Simvastatin or placebo treatment once daily for 12 weeks.

MAIN OUTCOME MEASURES

Primary outcomes were scores on a Rey complex figure test (delayed recall), cancellation test (speed), prism adaptation, and the mean brain apparent diffusion coefficient based on magnetic resonance imaging. Secondary outcome measures were scores on the cancellation test (standard deviation), Stroop color word test, block design, object assembly, Rey complex figure test (copy), Beery developmental test of visual-motor integration, and judgment of line orientation. Scores were corrected for baseline performance, age, and sex.

RESULTS

No significant differences were observed between the simvastatin and placebo groups on any primary outcome measure: Rey complex figure test (beta = 0.10; 95% confidence interval [CI], -0.36 to 0.56); cancellation test (beta = -0.19; 95% CI, -0.67 to 0.29); prism adaptation (odds ratio = 2.0; 95% CI, 0.55 to 7.37); and mean brain apparent diffusion coefficient (beta = 0.06; 95% CI, -0.07 to 0.20). In the secondary outcome measures, we found a significant improvement in the simvastatin group in object assembly scores (beta = 0.54; 95% CI, 0.08 to 1.01), which was specifically observed in children with poor baseline performance (beta = 0.80; 95% CI, 0.29 to 1.30). Other secondary outcome measures revealed no significant effect of simvastatin treatment.

CONCLUSION

In this 12-week trial, simvastatin did not improve cognitive function in children with NF1. Trial Registration isrctn.org Identifier: ISRCTN14965707.