Tracking of thinness and overweight in children of Dutch, Turkish, Moroccan and South Asian descent from 3 through 15 years of age: a historical cohort study.

BACKGROUND: Overweight is shown to track (= to maintain a relative position in a distribution) from childhood to adulthood, but is mostly studied in preobesogenic cohorts and in single ethnic groups. Little is known about tracking of thinness by ethnicity. OBJECTIVES: to determine (differences in) tracking of BMI (class) from 3 through 15 years and the prediction of BMI class at 13-15 years of age in contemporary Dutch, Turkish, Moroccan and South Asian children living in the Netherlands. METHODS: Historical cohort of 7625 children, born 1994-1997, with 24,376 measurements of BMI. BMI z-score and BMI class was analysed using universal criteria. South Asian children were also assessed using ethnic specific BMI criteria. Diagnostic odds ratios (OR) and test properties were calculated to estimate the ability of BMI class at 3-4 years to predict BMI class at 13-15 years. RESULTS: Tracking of thinness between 3 and 15 years was stronger than that of overweight, as indicated by a generally higher diagnostic OR. BMI trajectories between 3 and 15 years of age of thin, normal weight and overweight adolescents were, although significantly different, quite similarly shaped in children of Dutch, Turkish and Moroccan descent. The South Asian BMI trajectory deviated considerably from the other ethnic groups, but the differences disappeared when South Asian specific BMI criteria were applied. A substantial proportion of overweight developed between 5-10 years, after which less children shifted to other BMI classes. A total of 55-78% of children with overweight at 3-4 years retained their overweight at 13-15 years, and 10-20% of 3-4 year olds with thinness remained thin. CONCLUSIONS: In all ethnic groups, overweight and especially thinness highly tracked into adolescence. South Asian children differed from the other ethnic groups when universal BMI criteria were applied, but with South Asian specific BMI criteria tracking patterns became more concordant.

Specific language impairment is associated with maternal and family factors.

BACKGROUND: This study aimed to identify risk factors associated with specific language impairment (SLI). METHODS: In a nested case-control design, 253 children attending special needs schools for severe speech and language difficulties in the Netherlands were matched for sex and date of birth with 253 children attending mainstream education. Data on perinatal, maternal and family issues were retrieved from well-child care files registered shortly after birth. RESULTS: Children with SLI had younger mothers than children in the control group (mean 30 years 9 months vs. mean 31 years 9 months) (P = 0.02). Children with SLI were less frequently breastfed directly after birth (55% vs. 71%) (P = 0.0007) and were less frequently firstborns (33.3% vs. 46.2%) (P = 0.002). No statistically significant differences were found for any of the other risk factors. CONCLUSIONS: A relationship was found between SLI and maternal age, being breastfed and place in the birth order. Perinatal risk factors do not seem to be strongly associated with SLI.

To screen or not to screen for adolescent idiopathic scoliosis? A review of the literature.

OBJECTIVES: Over the years, there has been much debate about the desirability and efficacy of screening for adolescent idiopathic scoliosis. To analyse the current evidence from a public health point of view a renewed evaluation of the literature was performed. STUDY DESIGN: Literature review. METHODS: We performed two literature searches: from January 2000 to April 2015 for systematic reviews or guidelines on screening for adolescent idiopathic scoliosis and from January 2009 to April 2015 for all studies on adolescent idiopathic scoliosis and screening methods. We evaluated if screening for adolescent idiopathic scoliosis fulfils the criteria of the UK National Screenings Committee for appraising a screening programme. RESULTS: Adolescent idiopathic scoliosis is a condition with an unpredictable natural history. The optimal age and frequency of screening are unknown; it is not possible to predict which patients will need (conservative or surgical) treatment. The Forward Bending Test has a positive predictive value of 2.6% and a sensitivity of 56% (95% CI 23-88%) for (conservative or surgical) treatment, and is therefore not valid enough for use in a screening programme. There seems to be sufficient evidence that brace treatment is effective for preventing progression of adolescent idiopathic scoliosis. It is not clear if screening is cost effective. CONCLUSIONS: Despite evidence that brace treatment is effective for preventing progression of adolescent idiopathic scoliosis, the benefits from the screening programme do not outweigh the harms. From a Public Health point of view, there is not enough evidence to support a screening programme for adolescent idiopathic scoliosis.

Newborn hearing screening in youth health care in the Netherlands: National results of implementation and follow-up.

OBJECTIVE: The aim of this study is to investigate whether the quality of the Dutch, community based, universal newborn hearing screening programme is consistent over time. DESIGN: Universal newborn hearing screening data from three cohorts are compared on a number of quality targets concerning the outcome of the screening and the process of the screening in a three stage, community based, hearing screening programme. STUDY SAMPLE: A total of 552 820 children entered the study (189 794 in 2002-2006; 181 574 in 2008, and 181 452 in 2009). RESULTS: Participation in the programme is high from implementation onwards and increases over time for all screen stages to percentages above 99%. Refer rates are within quality targets and they are consistent over time. The screening is completed within 42 days of birth for 91.5% of the children in the last cohort. Of all children screened, 0.29% to 0.30% are referred to a speech and hearing centre. Participation in diagnostic testing is 93.3% to 95.2%. Of all referred children 77% to 85% receive a diagnosis within 122 days of birth. CONCLUSIONS: A good quality neonatal hearing screening programme in youth health care has been established in the Netherlands. However, both participation in diagnostic testing after a positive screen result and the timing of the diagnostic testing can still be improved.

Ten-year quality assurance of the nationwide hearing screening programme in Dutch neonatal intensive care units.

AIM: To evaluate 10-year quality assurance of newborn hearing screening (NHS) in Dutch neonatal intensive care units (NICU). METHODS: Results of the two-stage automated auditory brainstem response (AABR) screening and diagnostic examination in NICU graduates were centrally registered between October 1998 and December 2008. This registration facilitates screening, tracking and follow-up after abnormal screening results. Outcome measures are referral rates, prevalence rate of hearing loss and (trends of) coverage rates and timeliness of follow-up. RESULTS: Thirty-two thousand one hundred and two infants have been screened. Referral rates were 9.2% at the first and 26.3% at the second stage. Hearing loss was diagnosed in 728 infants (2.2%). Coverage rates were 98.7% at the first, 92.1% at the second stage, 92.3% for the diagnostic examination and 97.9% for the complete programme. After correction for gestational age, 95.8% of the infants had their first AABR<1 month, 81.8% of the referred infants had their second AABR<6 weeks and 67.1% were diagnosed<3 months. There was a positive trend in referred infants that had their second AABR<6 weeks (p=0.004) as well as in infants diagnosed<3 months (p<0.001). CONCLUSION: The NHS in Dutch NICUs is effective. Timely identification of hearing loss is improving over time.

Risk indicators for hearing loss in infants treated in different neonatal intensive care units.

AIM: To assess which infants' characteristics and specialized procedures are risk indicators for unilateral or bilateral hearing loss (HL) and to evaluate whether these risk indicators are associated with variation in prevalence of HL between Neonatal Intensive Care Units (NICUs). METHODS: For 2002-2005, data from the NICU hearing screening database in the Netherlands were matched with the national neonatology database in which all NICU infants with their patient characteristics and specialized procedures are registered. Multivariate logistic regression analyses were performed to assess risk indicators for HL and to explain differences in prevalence rates between NICUs. RESULTS: A total of 10 830 infants were available for analyses. The prevalence of HL was 1.8% and ranged from 0.7 to 3.7% between NICUs. Infants' characteristics that significantly increased the risk of HL were the presence of craniofacial anomalies, chomosomal/syndromal anomalies, central nervous system conditions, circulatory system conditions and intra-uterine infections. The specialized procedures involving > or =12 days of intensive care and high frequency oxygenation ventilation were independent risk indicators for HL. Approximately 20% of the variance can be explained by the studied risk indicators. Differences in prevalence rates between NICUs were slightly reduced after adjustment for these risk indicators. NICUs with the highest prevalence rates of HL were situated in the largest cities in the Netherlands with a mixed population because of immigration. Therefore, ethnicity may be a risk indicator. CONCLUSIONS: Several independent risk indicators for HL were found, but they could not explain all differences in prevalence rates of HL between NICUs.

Clinical and genetic characteristics of Dutch children with central congenital hypothyroidism, early detected by neonatal screening.

OBJECTIVE: To evaluate clinical characteristics of patients with central congenital hypothyroidism (CH), detected in the Dutch neonatal screening program. This included patients with isolated central CH but the majority have multiple pituitary hormone deficiencies (MPHD). DESIGN: Nationwide, cross-sectional study. METHODS: Data was collected on clinical characteristics, endocrine tests and neuroimaging of central CH patients, detected by the Dutch neonatal screening and born between 1 January 1995 and 1 January 2015. Height and pubertal status were assessed during a study visit. Isolated central CH patients without a confirmed genetic diagnosis were offered genetic (re-)testing. RESULTS: During the 20-year period 154 central CH patients were detected (incidence of permanent central CH 1:25 642). After excluding deceased (15), severe syndromic (7) and transient patients (6), 92 of 126 eligible patients were included (57 MPHD; 79% male). Sixty-one patients (50 MPHD) had been hospitalized before screening results were reported, but central CH was diagnosed on clinical grounds in only three of them (5%). MRI abnormalities consistent with pituitary stalk interruption syndrome were seen in 50 (93%) MPHD patients. Among isolated central CH patients, 27 (84%) had an IGSF1, TBL1X or IRS4 gene variant (53, 16 and 16%, respectively). CONCLUSION: Many patients with central CH have neonatal health problems, especially MPHD patients. Despite hospital admission of two-thirds of patients, almost none were diagnosed clinically, but only after the notification of an abnormal screening result was received. This indicates that central CH, especially if isolated, is an easily missed clinical diagnosis.

Phenylalanine tolerance can already reliably be assessed at the age of 2 years in patients with PKU.

BACKGROUND: The clinical severity of phenylalanine hydroxylase deficiency is usually defined by either pre-treatment phenylalanine (Phe) concentration or Phe tolerance at 5 years of age. So far, little is known about the course of Phe tolerance or the ability of both pre-treatment Phe and Phe tolerance at early age to predict Phe tolerance at later age. AIM: This study was conducted to investigate the course of the individual Phe tolerance and to assess the predictive value of both the pre-treatment Phe concentration and Phe tolerance at 1 and 6 months and 1, 2, 3 and 5 years for Phe tolerance at 10 years of age. METHOD: Data on blood Phe concentration, prescribed Phe intake and weight of 213 early and continuously treated Dutch PKU patients up to 10 years of age were collected. Data acquired under good metabolic control were used in the study. Tolerance was expressed in mg/day and mg/kg per day. RESULTS: Data at 1 and 6 months and at 1, 2, 3 and 5 years of 61, 58, 59, 57, 56 and 59 patients were included for comparison with the Phe tolerance at 10 years. Phe tolerances (mg/kg per day) at 2, 3 and 5 years showed a clear correlation with the tolerance at 10 years of age (r = 0.608, r = 0.725 and r = 0.661). Results for tolerance expressed as mg/day were comparable. Pre-treatment Phe concentrations did not correlate significantly with the tolerance. CONCLUSION: Pre-treatment Phe is unreliable but Phe tolerance is a reliable predictor of the tolerance at 10 years of age, starting at 2 years of age.

[Weight loss, serum sodium concentration and residual symptoms in patients with hypernatremic dehydration caused by insufficient breastfeeding]. / Gewichtsverlies, serumnatriumconcentratie en restverschijnselen bij patiëntjes met hypertone dehydratie door onvoldoende borstvoeding.

OBJECTIVE: To determine the relationship between serum sodium concentration and weight loss as well as residual symptoms in newborns with hypernatremic dehydration caused by insufficient breastfeeding; and to determine the sensitivity of the following rule of thumb 'if weight loss is less than 10%, the baby does not have hypernatremic dehydration caused by insufficient breastfeeding'. DESIGN: Systematic literature search. METHOD: Medline was searched using the terms 'dehydration AND breastfeeding' for case reports on patients with 'hypernatremic dehydration caused by insufficient breastfeeding'. Reference lists from the articles retrieved were also searched. Articles published in 1970-2004 in Dutch, English, French, and German were included. All cases that the author diagnosed as 'hypernatremic dehydration caused by insufficient breastfeeding' were included. RESULTS: A total of 47 articles were found, containing 128 relevant cases. Of these, 9 had less than 10% weight loss. Therefore, the sensitivity of the 10% rule was 93%. We found a linear relationship between the degree of weight loss and serum sodium concentration (Pearson's correlation coefficient = 0.71; p < 0.001). For every 10% increase in weight loss, the serum sodium concentration increased by 16 mmol/l (95% CI: 13-19). As the serum sodium concentration increased, the prevalence of residual symptoms increased. No residual symptoms were reported in patients with less than 10% weight loss. CONCLUSION: A relatively strong linear relationship was found between weight loss and serum sodium concentration. If the weight loss was more than 10%, the serum sodium concentration was beyond the range of normal values. The rule of thumb had a high sensitivity; however, the specificity should be determined before the rule of thumb is implemented.

Growth monitoring and diagnostic work-up of short stature: an international inventorization.

BACKGROUND/AIMS: Growth monitoring is almost universally performed, but few data are available on which referral criteria and diagnostic work-up are used worldwide for children with short stature. METHODS: A short questionnaire, containing questions on auxological screening and on diagnostic criteria for short stature, was sent to all members of the European Society of Paediatric Endocrinology (ESPE) and to several pediatric endocrinologists outside Europe. RESULTS: Responses were received from 36 countries. In 27 (75%) a child health care program existed and in 14 (39%) there was a protocol for referral of children with growth retardation. Height for age was mostly used as a referral criterion. Sixteen countries (45%) reported having a guideline in secondary health care for diagnostic work-up. Although all countries agreed on having biochemical, radiological and/or genetic tests in the diagnostic work-up, there was a wide variety of recommended tests. CONCLUSIONS: There is little consensus on referral criteria and diagnostic work-up of children with short stature among industrialized countries. There is a need to establish evidence-based guidelines.

Cost-effectiveness of newborn screening for cystic fibrosis determined with real-life data.

BACKGROUND: Previous cost-effectiveness studies using data from the literature showed that newborn screening for cystic fibrosis (NBSCF) is a good economic option with positive health effects and longer survival. METHODS: We used primary data to compare cost-effectiveness of four screening strategies for NBSCF, i.e. immunoreactive trypsinogen-testing followed by pancreatitis-associated protein-testing (IRT-PAP), IRT-DNA, IRT-DNA-sequencing, and IRT-PAP-DNA-sequencing, each compared to no-screening. A previously developed decision analysis model for NBSCF was fed with model parameters mainly based on a study evaluating two novel screening strategies among 145,499 newborns in The Netherlands. RESULTS: The four screening strategies had cost-effectiveness ratios varying from €23,600 to €29,200 per life-year gained. IRT-PAP had the most favourable cost-effectiveness ratio. Additional life-years can be gained by IRT-DNA but against higher costs. When treatment costs reduce with 5% due to early diagnosis, screening will lead to financial savings. CONCLUSION: NBSCF is as an economically justifiable public health initiative. Of the four strategies tested IRT-PAP is the most economic and this finding should be included in any decision making model, when considering implementation of newborn screening for CF.

Sustained attention and inhibition of cognitive interference in treated phenylketonuria: associations with concurrent and lifetime phenylalanine concentrations.

Fifty-seven 7-14-year-old early- and continuously treated phenylketonuria (PKU) patients and 65 matched controls performed a sustained attention task. PKU patients with plasma phenylalanine (phe) levels higher than 360 micromol/l at the time of testing exhibited, compared to controls, lower speed of information processing, a lower ability to inhibit task-induced cognitive interference, less consistent performance, and a stronger decrease of performance level over time. Patients with concurrent phe levels lower than 360 micromol/l did not differ from controls and were significantly better than patients with levels higher than 360 micromol/l. Strong relationships were found with task performance for phe levels during the pre-school years and between ages 5 and 7. These correlations were stronger than those between concurrent phe level and task performance. Significant multiple regression models were found with age accounting for the largest proportion of variance of tempo and tempo fluctuation, and lifetime phe levels (particularly phe level between ages 5 and 7) accounting for the largest proportion of variance of the relative number of inhibition errors and its increase over time. Phe level between ages 5 and 7 also contributed significantly to the variance of tempo and tempo fluctuation. Neuropsychological outcome was independent of IQ. The results indicate that strict dietary adherence during these periods is beneficial to attentional control later in life. We suggest that phe levels should be maintained under 360 micromol/l until approximately age 12, when development of attentional control approaches an adult level.

Non-differential underestimation may cause a threshold effect of exposure to appear as a dose-response relationship.

It is generally believed that non-differential misclassification will lead to a bias toward the null-value. However, using one graphical and one numerical example, we show that in situations where underestimation more than overestimation is the problem, non-differential misclassification may lead to a bias away from the null-value for intermediate categories of exposure variables. We show that a true threshold level for an exposure may, subsequently, appear as a dose-response relationship. Underestimation more than overestimation is likely to occur in studies in which self-reports are used to obtain data on activities which respondents voluntarily engage in and which are socially not acceptable or known to be potentially dangerous. Researchers should be aware that both a shown deleterious effect at a low level of exposure and a dose-response relationship may in fact be spurious and due to underestimation of exposure at higher levels.

The impact of alcohol misclassification on the relationship between alcohol and pregnancy outcome.

Underreporting, more than overreporting, is a problem in studies of the effects of alcohol consumption using self-reported data. Numerical examples illustrate that in studies of the effect of alcohol, nondifferential misclassification of alcohol consumption due to underreporting may lead to a bias away from the null value. It may also cause a true threshold level for alcohol to appear as a dose-response relationship. It is shown that the effect of misclassification on effect estimates will depend on the true frequency of abstainers in the studied population.

Differential misclassification of alcohol and cigarette consumption by pregnancy outcome.

BACKGROUND: The validity of the results of studies using retrospectively collected information on exposures is often criticized, because cases may report differently from controls even if their true exposure status is the same. This study was performed to quantify the extent to which this effect (differential misclassification) may occur for alcohol and cigarette consumption by pregnancy outcome. METHODS: Prospective as well as retrospective information on alcohol and cigarette consumption was collected for 2806 mothers resident in all 12 provinces of the Netherlands, who gave birth between 1978 and 1979. Changes in mean reported consumption and changes from user to non-user based on retrospective and prospective information were compared for cases and controls. This was done by calculating absolute differences (retrospective minus prospective) in reported consumption and by calculating 'misclassification odds ratios'. Further, conventional odds ratios based on retrospective information were compared with those based on prospective information. Outcome measures were stillbirth, small for gestational age (SGA), congenital malformations, preterm birth and low birthweight. RESULTS: The only statistically significant result was found for smoking and SGA. Mothers with an SGA child retrospectively reported a higher number of cigarettes smoked than they had prospectively, more so than mothers of a control child. However, the odds ratios of the relation between SGA and smoking based on prospective and retrospective information, respectively, were virtually the same. CONCLUSIONS: Our results suggest that information bias is unlikely to have a large influence on effect estimates in studies using retrospective information on alcohol and cigarette consumption.

Quantum effects on liquid dynamics as evidenced by the presence of well-defined collective excitations in liquid para-hydrogen

The origin of the well-defined collective excitations found in liquid para-H2 by recent experiments is investigated. The persistence of their relatively long lifetimes down to microscopic scales is well accounted for by calculations carried out by means of path-integral-centroid molecular dynamics. In contrast only overdamped excitations are found in calculations carried within the classical limit. The results provide fully quantitative evidence of quantum effects on the dynamics of a simple liquid.

Motor function under lower and higher controlled processing demands in early and continuously treated phenylketonuria.

This study examined motor control in 61 early and continuously treated patients with phenylketonuria (PKU) and 69 control participants, aged 7 to 14 years. The pursuit task demanded concurrent planning and execution of unpredictable movements, whereas the tracking task required a highly automated circular movement that could be planned in advance. PKU patients showed significantly poorer motor control in both tasks compared with control participants. Deficits were particularly observed for younger patients (age < 11 years). Differences between control participants and PKU patients were significantly greater in the pursuit task compared with the tracking task, indicating more serious deficits when a higher level of controlled processing is required. Correlations with historical phenylalanine levels indicated a later maturation of the level of control required by the pursuit task compared with the tracking task.

Costs of different strategies for neonatal hearing screening: a modelling approach.

OBJECTIVE: To compare the cost effectiveness of various strategies for neonatal hearing screening by estimating the cost per hearing impaired child detected. DESIGN: Cost analyses with a simulation model, including a multivariate sensitivity analysis. Comparisons of the cost per child detected were made for: screening method (automated auditory brainstem response or otoacoustic emissions); number of stages in the screening process (two or three); target disorder (bilateral hearing loss or both unilateral and bilateral loss); location (at home or at a child health clinic). SETTING: The Netherlands TARGET POPULATION: All newborn infants not admitted to neonatal intensive care units. MAIN OUTCOME MEASURE: Costs per child detected with a hearing loss of 40 dB or more in the better ear. RESULTS: Costs of a three stage screening process in child health clinics are 39.0 pounds (95% confidence interval 20.0 to 57.0) per child detected with automated auditory brainstem response compared with 25.0 (14.4 to 35.6) pounds per child detected with otoacoustic emissions. A three stage screening process not only reduces the referral rates, but is also likely to cost less than a two stage process because of the lower cost of diagnostic facilities. The extra cost (over and above a screening programme detecting bilateral losses) of detecting one child with unilateral hearing loss is 1500-4000 pounds. With the currently available information, no preference can be expressed for a screening location. CONCLUSIONS: Three stage screening with otoacoustic emissions is recommended. Whether screening at home is more cost effective than screening at a child health clinic needs further study.

The effect of moderate maternal alcohol consumption on birth weight and gestational age in a low risk population.

We analyzed the relationship between moderate maternal alcohol consumption during pregnancy and both birth weight corrected for gestational age and preterm delivery in 3447 women. Information on alcohol consumption in the first and second trimester was obtained during mid pregnancy and information about third trimester drinking was obtained a few days after delivery. After adjustment for possible confounders we found that for most women alcohol consumption was unrelated to birth weight corrected for gestational age and preterm delivery. However, in the subgroup of women smoking 20 cigarettes or more a day, drinking more than 120 g alcohol a week in early pregnancy was associated with a 7.2% (95% CI 0.2% to 14.2%) decrease in birth weight. We conclude that the effect of alcohol use on birth weight corrected for gestational age and gestational age is limited. However, in women who smoke heavily, a reported consumption of about two drinks or more a day in early pregnancy may be an additional risk factor for impaired fetal growth.