Stef van Buuren

VU medisch centrum, Amsterdam, North Holland, Netherlands

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Publications (36)93.87 Total impact

  • Article: Methods to obtain referral criteria in growth monitoring.
    Paula van Dommelen, Stef van Buuren
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    ABSTRACT: An important goal of growth monitoring is to identify genetic disorders, diseases or other conditions that manifest themselves through an abnormal growth. The two main conditions that can be detected by height monitoring are Turner's syndrome and growth hormone deficiency. Conditions or risk factors that can be detected by monitoring weight or body mass index include hypernatremic dehydration, celiac disease, cystic fibrosis and obesity. Monitoring infant head growth can be used to detect macrocephaly, developmental disorder and ill health in childhood. This paper describes statistical methods to obtain evidence-based referral criteria in growth monitoring. The referral criteria that we discuss are based on either anthropometric measurement(s) at a fixed age using (1) a Centile or a Standard Deviation Score, (2) a Standard Deviation corrected for parental height, (3) a Likelihood Ratio Statistic and (4) an ellipse, or on multiple measurements over time using (5) a growth rate and (6) a growth curve model. We review the potential uses of these methods, and outline their strengths and limitations.
    Statistical Methods in Medical Research 02/2013; · 2.44 Impact Factor
  • Article: Trends in Menarcheal Age between 1955 and 2009 in the Netherlands.
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    ABSTRACT: To assess and compare the secular trend in age at menarche in Dutch girls (1955-2009) and girls from Turkish and Moroccan descent living in the Netherlands (1997-2009). Data on growth and maturation were collected in 20,867 children of Dutch, Turkish and Moroccan descent in 2009 by trained health care professionals. Girls, 9 years and older, of Dutch (n = 2138), Turkish (n = 282), and Moroccan (n = 295) descent were asked whether they had experienced their first period. We compared median menarcheal age in 2009 with data from the previous Dutch Nationwide Growth Studies in 1955, 1965, 1980 and 1997. Age specific body mass index (BMI) z-scores were calculated to assess differences in BMI between pre- and postmenarcheal girls in different age groups. Median age at menarche in Dutch girls, decreased significantly from 13.66 years in 1955 to 13.15 years in 1997 and 13.05 years in 2009. Compared to Dutch girls there is a larger decrease in median age of menarche in girls of Turkish and Moroccan descent between 1997 and 2009. In Turkish girls age at menarche decreased from 12.80 to 12.50 years and in Moroccan girls from 12.90 to 12.60 years. Thirty-three percent of Turkish girls younger than 12 years start menstruating in primary school. BMI-SDS is significantly higher in postmenarcheal girls than in premenarcheal girls irrespective of age. There is a continuing secular trend in earlier age at menarche in Dutch girls. An even faster decrease in age at menarche is observed in girls of Turkish and Moroccan descent in the Netherlands.
    PLoS ONE 01/2013; 8(4):e60056. · 4.09 Impact Factor
  • Article: The world's tallest nation has stopped growing taller: the height of Dutch children 1955-2009.
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    ABSTRACT: Background:Records show that mean height in The Netherlands has increased since 1858. This study looks at whether this trend in the world's tallest nation is continuing, and we consider the influence of the geographical region, and of child and parental education, on changes in height.Methods:We compared the height of young Dutch people aged 0-21 years as determined on the basis of the growth study of 2009 with the height data from growth studies conducted in 1955, 1965, 1980, and 1997.Results:The analysis sample included 5,811 boys and 6,194 girls. Height by age was the same as in 1997. Mean final height was 183.8 cm (SD=7.1 cm) in boys and 170.7 cm (SD=6.3 cm) in girls. The educational levels of both children and their parents are positively correlated with mean height. Since 1997, differences between geographical regions have decreased but not vanished, with the northern population being the tallest.Conclusion:The world's tallest population has stopped growing taller after a period of 150 years. The cause is unclear. The Dutch may have reached the optimal height distribution. Alternatively, growth-promoting environmental factors may have stabilised in the last decade, preventing the population from attaining its full growth potential.Pediatric Research (2012); doi:10.1038/pr.2012.189.
    Pediatric Research 12/2012; · 2.70 Impact Factor
  • Article: High cardiovascular risk in severely obese young children and adolescents.
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    ABSTRACT: To assess the prevalence of cardiovascular risk factors in severely obese children and adolescents. A nationwide prospective surveillance study was carried out from July 2005 to July 2007 where paediatricians were asked to report all new cases of severe obesity in 2-18-year-old children to the Dutch Paediatric Surveillance Unit. Severe obesity is defined by gender and age-dependent cut-off points for body mass index based on Dutch National Growth Studies corresponding to the adult cut-off point of 35 kg/m(2). Paediatricians were asked to complete a questionnaire for every severely obese child regarding socio-demographic characteristics and cardiovascular risk factors (blood pressure, fasting blood glucose and lipids). In 2005, 2006 and 2007, 94%, 87% and 87%, respectively, of paediatricians in the Netherlands responded to the monthly request from the Dutch Paediatric Surveillance Unit and 500 children with newly diagnosed severe obesity were reported. 72.6% (n=363) of paediatricians responded to a subsequent questionnaire. Cardiovascular risk factor data were available in 255/307 (83%) children who were correctly classified as severely obese. 67% had at least one cardiovascular risk factor (56% hypertension, 14% high blood glucose, 0.7% type 2 diabetes and up to 54% low HDL-cholesterol). Remarkably, 62% of severely obese children aged ≤12 years already had one or more cardiovascular risk factors. A high number (2/3) of severely obese children have cardiovascular risk factors. Internationally accepted criteria for defining severe obesity and guidelines for early detection and treatment of severe obesity and comorbidity are urgently needed.
    Archives of Disease in Childhood 07/2012; 97(9):818-21. · 2.88 Impact Factor
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    Article: Healthy growth in children with Down syndrome.
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    ABSTRACT: To provide cross-sectional height and head circumference (HC) references for healthy Dutch children with Down syndrome (DS), while considering the influence of concomitant disorders on their growth, and to compare growth between children with DS and children from the general population. Longitudinal growth and medical data were retrospectively collected from medical records in 25 of the 30 regional hospital-based outpatient clinics for children with DS in The Netherlands. Children with Trisomy 21 karyotype of Dutch descent born after 1982 were included. The LMS method was applied to fit growth references. We enrolled 1,596 children, and collected 10,558 measurements for height and 1,778 for HC. Children with DS without concomitant disorders (otherwise healthy children) and those suffering only from mild congenital heart defects showed similar growth patterns. The established growth charts, based on all measurements of these two groups, demonstrate the three age periods when height differences between children with and without DS increase: during pregnancy, during the first three years of life, and during puberty. This growth pattern results in a mean final height of 163.4 cm in boys and 151.8 cm in girls (-2.9 standard deviation (SD) and -3.0 SD on general Dutch charts, respectively). Mean HC (0 to 15 months) was 2 SD less than in the general Dutch population. The charts are available at www.tno.nl/growth. Height and HC references showed that growth retardation in otherwise healthy children with DS meanly occurs in three critical periods of growth, resulting in shorter final stature and smaller HC than the general Dutch population shows. With these references, health care professionals can optimize their preventive care: monitoring growth of individual children with DS optimal, so that growth retarding comorbidities can be identified early, and focusing on the critical age periods to establish ways to optimize growth.
    PLoS ONE 01/2012; 7(2):e31079. · 4.09 Impact Factor
  • Article: A simple calculation of the target height.
    Archives of Disease in Childhood 12/2011; 97(2):182. · 2.88 Impact Factor
  • Article: Distinguishing symptom dimensions of depression and anxiety: an integrative approach.
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    ABSTRACT: Clark and Watson developed the tripartite model in which a symptom dimension of 'negative affect' covers common psychological distress that is typically seen in anxious and depressed patients. The 'positive affect' and 'somatic arousal' dimensions cover more specific symptoms. Although the model has met much support, it does not cover all relevant anxiety symptoms and its negative affect dimension is rather unspecific. Therefore, we aimed to extend the tripartite model in order to describe more specific symptom patterns with unidimensional measurement scales. 1333 outpatients provided self report data. To develop an extended factor model, exploratory factor analysis (EFA) was conducted in one part of the data (n=578). Confirmatory factor analysis (CFA) was conducted in the second part (n=755), to assess model-fit and comparison with other models. Rasch analyses were done to investigate the unidimensionality of the factors. EFA resulted in a 6-factor model: feelings of worthlessness, fatigue, somatic arousal, anxious apprehension, phobic fear and tension. CFA in the second sample showed that a 6-factor model with a hierarchical common severity factor fits the data better than alternative 1- and 3-factor models. Rasch analyses showed that each of the factors and the total of factors can be regarded as unidimensional measurement scales. The model is based on a restricted symptom-pool: more dimensions are likely to exist. The extended tripartite model describes the clinical state of patients more specifically. This is relevant for both clinical practice and research.
    Journal of affective disorders 10/2011; 136(3):693-701. · 3.76 Impact Factor
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    Article: Association between head circumference and body size.
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    ABSTRACT: Studies on the association between head circumference (HC) and height or weight have shown variable results. Using data from the Dutch nationwide survey performed in 1997 (n = 14,500), we calculated correlations for different ages, and fitted a regression model for the estimation of HC. HC versus height charts were created for different age groups. Data from children from other ethnic groups and children with various growth disorders were plotted on the charts and compared with reference data. Correlations between HC and height or weight showed similar patterns: highest at birth, followed by a rapid decline to a stable level and a peak in adolescence. On charts containing the regression line ±2 standard deviations for subjects aged 0-2 months and 2 months to 21 years, Turkish and Moroccan children, as well as children with idiopathic short stature and small for gestational age, had a normal HC for height, whereas children with an insulin-like growth factor 1 receptor defect or Sotos syndrome showed trends towards a smaller or larger HC for height, respectively. HC correlates strongly with height and weight. The charts of HC for height may serve as an additional tool to interpret HC in short or tall children.
    Hormone Research in Paediatrics 02/2011; 75(3):213-9.
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    Article: Increase in prevalence of overweight in Dutch children and adolescents: a comparison of nationwide growth studies in 1980, 1997 and 2009.
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    ABSTRACT: To assess the prevalence of overweight and obesity among Dutch children and adolescents, to examine the 30-years trend, and to create new body mass index reference charts. Nationwide cross-sectional data collection by trained health care professionals. 10,129 children of Dutch origin aged 0-21 years. Overweight (including obesity) and obesity prevalences for Dutch children, defined by the cut-off values on body mass index references according to the International Obesity Task Force. In 2009, 12.8% of the Dutch boys and 14.8% of the Dutch girls aged 2-21 years were overweight and 1.8% of the boys and 2.2% of the girls were classified as obese. This is a two to three fold higher prevalence in overweight and four to six fold increase in obesity since 1980. Since 1997, a substantial rise took place, especially in obesity, which increased 1.4 times in girls and doubled in boys. There was no increase in mean BMI SDS in the major cities since 1997. Overweight and obesity prevalences in 2009 were substantially higher than in 1980 and 1997. However, the overweight prevalence stabilized in the major cities. This might be an indication that the rising trend in overweight in The Netherlands is starting to turn.
    PLoS ONE 01/2011; 6(11):e27608. · 4.09 Impact Factor
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    Article: The Terneuzen Birth Cohort. Longer exclusive breastfeeding duration is associated with leaner body mass and a healthier diet in young adulthood.
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    ABSTRACT: Breastfeeding (BF) is protective against overweight and is associated with dietary behaviour. The aims of our study were to assess the relationship between exclusive BF duration and BMI, waist circumference (WC) and waist-hip ratio (WHR) at adulthood, and to study whether dietary behaviour could explain the relationship between BF duration and the proxies of fat mass. In 2004-2005, 822 subjects from the Terneuzen Birth Cohort (n = 2,604), aged 18-28 years, filled in postal questionnaires including sociodemographic factors and aspects of dietary behaviour (dietary pattern, and consumption of fruit and vegetables, snacks, sweetened beverages and alcohol); 737 subjects also underwent anthropometric measurements of weight, height, and waist and hip circumference. The relationship between exclusive BF duration and dietary outcomes was investigated by logistic regression analysis. The relationships of BF duration with the anthropometric measures were investigated by linear regression analyses. All results were corrected for age, gender and possible confounders. Finally, regression analyses were performed to investigate if diet factors had a mediating effect on the relationship between BF duration and fat mass. A significant inverse dose-response relationship of BF duration was found for BMI (β-0.13, SE 0.06), WC (β-0.39, SE 0.18) and WHR (β-0.003, SE 0.001), after correction for age, gender and confounders. The odds ratio (OR) of exclusive BF duration in months for a breakfast frequency of at least 5 times a week was 1.16 (95%CI 1.06-1.27), and for snack consumption of less than twice a week was 1.15 (95%CI 1.06-1.25). Both ORs were corrected for age, gender and confounders. For other dietary outcomes, the results point in the same direction, i.e. a positive relationship with BF duration, but these were not statistically significant. A mediating effect of the diet factors on the association between BF and anthropometric outcomes was not shown. Exclusive BF duration had a significant inverse dose-response relationship with BMI, WC and WHR at young adulthood. BF duration was positively related to a healthier diet at adulthood, but this did not explain the protective effect of BF against body fat. Our results underline the recommendation of the WHO to exclusively breastfeed for 6 months or longer.
    BMC Pediatrics 01/2011; 11:33. · 1.88 Impact Factor
  • Article: Identifying young children without overweight at high risk for adult overweight: the Terneuzen Birth Cohort.
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    ABSTRACT: To develop a tool to identify children with high risk of adult overweight (AO), especially before developing overweight, based on body mass index (BMI) standard deviation score(s) (SDS) changes between 2-6 years (y) of age. We fitted a linear spline model to BMI SDS of 762 young Caucasian adults from the Terneuzen Birth Cohort at fixed ages between birth and 18 y. By linear regression analysis, we assessed the increase in explained variance of the adult BMI SDS by adding the BMI SDS at 2 y to the models including the BMI SDS at 4 y, 6 y and both 4 y and 6 y. AO risk was modelled by logistic regression. The internal validity was estimated using bootstrap techniques. Risk models were represented as risk score diagrams by gender for the age intervals 2-4 y and 2-6 y. In addition to the BMI SDS at certain ages, the previous BMI SDS during childhood is positively related to adult weight. Receiver Operating Curves analysis provides insight into sensible cut-offs (AUC varied from 0.76 to 0.83). The sensitivity and specificity for 2-6 y at the cut-off of 0.25 and 0.5 are respectively, 0.76 and 0.74, and 0.36 and 0.93, whereas the PPV is 0.52 and 0.67, respectively. The risk score diagrams can serve as a tool for young children for primary prevention of adult overweight. To avoid wrongly designating children at risk for AO, we propose a cut-off with a high specificity at the risk of approximately 0.5. After external validation, wider adoption of this tool might enhance primary AO prevention.
    International journal of pediatric obesity: IJPO: an official journal of the International Association for the Study of Obesity 11/2010; 6(2-2):e187-95. · 2.00 Impact Factor
  • Article: The prognosis of chronic low back pain is determined by changes in pain and disability in the initial period.
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    ABSTRACT: The recovery of patients with chronic low back pain (LBP) is slow. Furthermore, it is recently proposed that chronic LBP needs a prognostic approach to determine who will develop clinically significant back pain. Therefore, it is imperative to identify prognostic factors that are mostly seen in chronic LBP patients at an early stage. This may give clinicians tailored advice to prevent chronicity or may refer to a specific intervention. To investigate the contribution of demographic, work, clinical, and psychosocial variables, including new prognostic variables as changes in pain intensity and disability status, on the development of chronic LBP. Prospective cohort data by merging data from three randomized trials (secondary analyses). Workers (n=628) on sick leave because of subacute nonspecific LBP. Chronic LBP for longer than 6 months (functional measure). Potential prognostic variables were demographic, work, clinical, and psychosocial characteristics (self-report measures). We also included as prognostic variables a clinically relevant change in pain intensity and disability status. For the selection of variables and prognostic models, bootstrapping techniques were used in combination with multivariable logistic regression. The explained variance and discrimination were used to evaluate the clinical performance of the models. The variables most strongly related to chronic LBP were as follows: no clinically relevant change in pain intensity and in disability status in the first 3 months, a higher pain intensity score at baseline, and a higher score for kinesiophobia. This prognostic model had a bootstrap-corrected explained variance of 37% and a discriminative ability (c index) of 0.80. Clinical-, work-, and psychosocial-related variables contribute to the development of chronic LBP. The most promising variables are a clinically relevant decrease in pain intensity and in disability status in the first 3 months. These variables are relevant for clinicians to advise their patients with respect to preventive measures or treatment strategies.
    The spine journal: official journal of the North American Spine Society 10/2010; 10(10):847-56. · 2.90 Impact Factor
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    Article: Efficacy and safety of oxandrolone in growth hormone-treated girls with turner syndrome.
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    ABSTRACT: Context and Objective: GH therapy increases growth and adult height in Turner syndrome (TS). The benefit to risk ratio of adding the weak androgen oxandrolone (Ox) to GH is unclear. Design and Participants: A randomized, placebo-controlled, double-blind, dose-response study was performed in 10 centers in The Netherlands. One hundred thirty-three patients with TS were included in age group 1 (2-7.99 yr), 2 (8-11.99 yr), or 3 (12-15.99 yr). Patients were treated with GH (1.33 mg/m(2) . d) from baseline, combined with placebo (Pl) or Ox in low (0.03 mg/kg . d) or conventional (0.06 mg/kg . d) dose from the age of 8 yr and estrogens from the age of 12 yr. Adult height gain (adult height minus predicted adult height) and safety parameters were systematically assessed. Results: Compared with GH+Pl, GH+Ox 0.03 increased adult height gain in the intention-to-treat analysis (mean +/- sd, 9.5 +/- 4.7 vs. 7.2 +/- 4.0 cm, P = 0.02) and per-protocol analysis (9.8 +/- 4.9 vs. 6.8 +/- 4.4 cm, P = 0.02). Partly due to accelerated bone maturation (P < 0.001), adult height gain on GH+Ox 0.06 was not significantly different from that on GH+Pl (8.3 +/- 4.7 vs. 7.2 +/- 4.0 cm, P = 0.3). Breast development was slower on GH+Ox (GH+Ox 0.03, P = 0.02; GH+Ox 0.06, P = 0.05), and more girls reported virilization on GH+Ox 0.06 than on GH+Pl (P < 0.001). Conclusions: In GH-treated girls with TS, we discourage the use of the conventional Ox dosage (0.06 mg/kg . d) because of its low benefit to risk ratio. The addition of Ox 0.03 mg/kg . d modestly increases adult height gain and has a fairly good safety profile, except for some deceleration of breast development.
    The Journal of clinical endocrinology and metabolism 03/2010; 95(3):1151-60. · 6.50 Impact Factor
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    Article: The Terneuzen birth cohort: BMI changes between 2 and 6 years correlate strongest with adult overweight.
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    ABSTRACT: Complications of overweight amplify with age, and irreversible damage already exists in young persons. Identifying the most sensitive age interval(s) for adult overweight is relevant for primary prevention. The aim of the study was to assess the relative contribution of body mass index (BMI) changes between 0 and 18 years to adult overweight, and to identify the earliest critical growth period. Data from 762 subjects in the Terneuzen Birth Cohort with an average of 21 growth measurements per subject from birth until 18 years were used. The main outcome measure was the BMI standard deviation score (SDS) at young adulthood. For each subject BMI SDS was fitted by a piecewise linear model at eight different ages and correlated to adult BMI SDS. The age intervals in between are considered critical according to three criteria, tested by respectively Students' t-tests, multiple linear regression analyses and Pearson's correlation tests. In the age intervals 4 months(m) -1 year(y), 2-6 y, 6-10 y and 10-18 y the BMI SDS change differs between adults with and without overweight (P<or=0.001). The age intervals 2-6 y and 10-18 y also meet the second criterion, implying that the BMI change during this period has a predictive value for adult BMI SDS in addition to BMI SDS at the end of the period. The largest rise in correlation between estimated BMI SDS and measured adult BMI SDS occurs during the period 2-6 y (from 0.36 to 0.63), which results in a high sensitivity (0.6) and specificity (0.8) by the age of 6 y. The age interval from 2 y to 6 y is the earliest and most critical growth period for adult overweight. Therefore, primary prevention of adult overweight seems most likely to be successful if targeted at this specific age interval. By identifying those with an upwards centile crossing between 2 and 6 years, the development towards adult overweight might be reversed.
    PLoS ONE 01/2010; 5(2):e9155. · 4.09 Impact Factor
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    Article: The Terneuzen Birth Cohort: BMI change between 2 and 6 years is most predictive of adult cardiometabolic risk.
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    ABSTRACT: We recently reported the age interval 2-6y being the earliest and most critical for adult overweight. We now aim to determine which age intervals are predictive of cardiometabolic risk at young adulthood. We analyzed data from 642 18-28 years olds from the Terneuzen Birth Cohort. Individual BMI SDS trajectories were fitted by a piecewise linear model. By multiple regression analyses relationships were assessed between subsequent conditional BMI SDS changes and components of the metabolic syndrome (MetS), skinfold thickness and hsCRP at young adulthood. Results were adjusted for gender and age, and other confounders. Gender was studied as an effect modifier. All BMI SDS changes throughout childhood were related to waist circumference and skinfold thickness. No other significant relationship was found before the age of 2 years, except between the BMI SDS change 0-1y and hsCRP. Fasting blood glucose was not predicted by any BMI SDS change. BMI SDS change 2-6y was strongly related to most outcome variables, especially to waist circumference (ß 0.47, SE 0.02), systolic and diastolic blood pressure (ß 0.20 SE 0.04 and ß 0.19 SE 0.03), and hsCRP (ß 0.16 SE 0.04). The BMI SDS change 10-18y was most strongly related to HDL cholesterol (ß -0.10, SE 0.03), and triglycerides (ß 0.21, SE 0.03). To a lesser degree, the BMI SDS change 6-10y was related to most outcome variables. BMI SDS changes 2-6y and 10-18y were significantly related to MetS: the OR was respectively 3.39 (95%CI 2.33-4.94) and 2.84 (95%CI 1.94-4.15). BMI SDS changes from 2y onwards were related to cardiometabolic risk at young adulthood, the age interval 2-6y being the most predictive. Monitoring and stabilizing the BMI SDS of children as young as 2-6y may not only reverse the progression towards adult overweight, but it may also safeguard cardiometabolic status.
    PLoS ONE 01/2010; 5(11):e13966. · 4.09 Impact Factor
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    Article: Effects of selective dropout on infant growth standards.
    Stef van Buuren
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    ABSTRACT: Exclusively breastfed (EBF) infants have higher weight gain during the first 2 months, and lower thereafter. The explanation for this phenomenon is not clear. Longitudinal data from the Social Medical Survey of Children Attending Child Health Clinics study with a cohort of 2,151 Dutch children were analyzed according to a pattern mixture model. It appears that higher than average growth of EBF infants during the first 2 months is primarily attributable to selective dropout. Furthermore, between months 2 and 6, light nonEBF infants gain more weight than light EBF infants. Both factors aid in explaining differences in growth between EBF and nonEBF infants. The WHO Child Growth Standards for weight-for-age have been calculated from a subgroup of 903 infants (out of 1,743) that complied with strict feeding criteria. If similar dropout mechanisms operate in the Multicentre Growth Reference Study, then the WHO weight-for-age standards are expected to be systematically different from those for the entire group of 1,743 infants.
    Nestle Nutrition workshop series. Paediatric programme 01/2010; 65:167-75; discussion 175-9.
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    Article: Return to work in a cohort of low back pain patients: development and validation of a clinical prediction rule.
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    ABSTRACT: From the viewpoint of cost prevention, it is necessary to identify patients that are of high risk for long-term work disability, production loss and sick-leave. Secondary data analysis in a cohort of 628 workers on sick-leave between 3 and 6 weeks due to low back pain (LBP). The association of a broad set of demographic, work, LBP and psychosocial related factors on lasting return to work was studied using Cox regression analysis with backward selection. The most relevant factors were used to derive a clinical prediction rule to determine the risk of sick-leave of more than 6 months. Variable and model selection and clinical model performance were performed with bootstrapping techniques. Also the test characteristics of the clinical model were considered. Longer work absence is related to "moderate" to "poor" job satisfaction, a higher score of fear avoidance beliefs, higher pain intensity at baseline, a longer duration of complaints and being of female gender. Calibration and discrimination of the clinical prediction rule were 0.90 (slope) and 0.63 (c-index), respectively. The explained variance of 6% of the prediction rule was low and the clinical performance in terms of sensitivity, specificity, positive and negative predictive values at specific cut-off points was moderate. Our study confirmed the importance of demographic, work, LBP and psychosocial related factors on the prediction of long-term sick-leave. When these factors were used to derive a clinical prediction rule the performance was moderate. As a consequence, prudence has to be taken when using the prediction rule in practice.
    Journal of Occupational Rehabilitation 03/2009; 19(2):155-65. · 2.80 Impact Factor
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    Article: Growth monitoring to detect children with cystic fibrosis.
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    ABSTRACT: Cystic fibrosis (CF) in infancy and childhood is often associated with failure to thrive (FTT). This would suggest that in countries without a newborn screening program for CF, FTT could be used as a clinical screening tool. The aim of this study is to assess the diagnostic performance of FTT for identifying children with CF. Longitudinal length and weight measurements up to 2.5 years of age were used from CF patients (n = 123) and a reference group (n = 2,151) in The Netherlands. Growth measurements after diagnosis were excluded. We developed five potential screening rules based upon length, weight and body mass index (BMI) standardized by age and gender (SDS). Outcome measures were sensitivity, specificity and positive predictive value (PPV). BMI SDS had the highest sensitivity at low false-positive rates. An efficient scenario is a BMI SDS below -2.5 SD in combination with a decrease in BMI SDS of at least 0.5 SD. This scenario had a sensitivity of 32%, a specificity of 98.3% and a PPV of 0.75%. In the absence of a newborn screening program, young children with FTT for BMI are candidates to consider testing for CF.
    Hormone Research 01/2009; 72(4):218-24. · 2.48 Impact Factor
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    Article: Breastfeeding duration related to practised contraception in the Netherlands.
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    ABSTRACT: The aim of this study was to gain insight into contraception practised and related to breastfeeding duration. Mothers with infants up to 6 months received a questionnaire on infant feeding (breast or formula feeding) and contraception (hormonal or non-hormonal methods). Estimates of the time interval between resuming contraception and cessation of lactation was calculated by Chained Equations Multiple Imputation. Of all women (n = 2710), 30% choose condoms, 22% the combined oral contraceptive pill (OCP) and few other methods. Breastfeeding was started by 80%, and 18% continued up to 6 months. Of the breastfeeding mothers, 5% used hormonal contraception; 7% of women who used hormonal contraception practised breastfeeding. After adjustment for background variables, the use of OCP is strongly associated with formula feeding: after delivery to the third month postpartum, the crude OR being 17.5 (95% CI: 11.3-27.0), the adjusted OR 14.5 (9.3-22.5); between the third and sixth month postpartum, respectively, 13.1 (95% CI: 8.6-19.9) and 11.7 (7.6-17.9). Of all breastfeeding women, 20-27% resumed OCP at 25 weeks postpartum and 80% introduced formula feeding. The time lag between these events is 6 weeks. Hormonal contraception was resumed after formula introduction. Mothers avoid hormonal contraception during lactation; they change to formula feeding 6 weeks before they resume the OCP. To effectively promote longer duration of breastfeeding, the BFHI needs to address contraception as practised.
    Acta Paediatrica 10/2008; 98(1):86-90. · 2.07 Impact Factor
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    Article: Screening rules for growth to detect celiac disease: a case-control simulation study.
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    ABSTRACT: It is generally assumed that most patients with celiac disease (CD) have a slowed growth in terms of length (or height) and weight. However, the effectiveness of slowed growth as a tool for identifying children with CD is unknown. Our aim is to study the diagnostic efficiency of several growth criteria used to detect CD children. A case-control simulation study was carried out. Longitudinal length and weight measurements from birth to 2.5 years of age were used from three groups of CD patients (n = 134) (one group diagnosed by screening, two groups with clinical manifestations), and a reference group obtained from the Social Medical Survey of Children Attending Child Health Clinics (SMOCC) cohort (n = 2,151) in The Netherlands. The main outcome measures were sensitivity, specificity and positive predictive value (PPV) for each criterion. Body mass index (BMI) performed best for the groups with clinical manifestations. Thirty percent of the CD children with clinical manifestations and two percent of the reference children had a BMI Standard Deviation Score (SDS) less than -1.5 and a decrease in BMI SDS of at least -2.5 (PPV = 0.85%). The growth criteria did not discriminate between the screened CD group and the reference group. For the CD children with clinical manifestations, the most sensitive growth parameter is a decrease in BMI SDS. BMI is a better predictor than weight, and much better than length or height. Toddlers with CD detected by screening grow normally at this stage of the disease.
    BMC Pediatrics 10/2008; 8:35. · 1.88 Impact Factor

Institutions

  • 2008–2013
    • VU medisch centrum
      • Department of Public and Occupational Health
      Amsterdam, North Holland, Netherlands
  • 2003–2013
    • TNO
      Delft, South Holland, Netherlands
  • 2010
    • Centraal Bureau voor de Statistiek
      Den Haag, South Holland, Netherlands
  • 2007–2010
    • Leids Universitair Medisch Centrum
      • Department of Pediatrics
      Leiden, South Holland, Netherlands
    • VU University Amsterdam
      • IHS-Institute of Health Sciences
      Amsterdam, North Holland, Netherlands
    • Universiteit Utrecht
      Utrecht, Provincie Utrecht, Netherlands