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J Van den Broeck

Publications and source records attributed to J Van den Broeck.

At least 19 recordsLinked to original sources
PubMed2006

Construction of the World Health Organization child growth standards: selection of methods for attained growth curves.

The World Health Organization (WHO), in collaboration with a number of research institutions worldwide, is developing new child growth standards. As part of a broad consultative process for selecting the best statistical methods, WHO convened a group of statisticians and child growth experts to review available methods, develop a strategy for assessing their strengths and weaknesses, and discuss methodological issues likely to be faced in the process of constructing the new growth curves. To select the method(s) to be used, the group proposed a two-stage decision-making process. First, to select a few relevant methods based on a list of set criteria and, second, to compare the methods using available tests or other established procedures. The group reviewed 30 methods for attained growth curves. Using the pre-defined criteria, a few were selected combining five distributions and two smoothing techniques. Because the number of selected methods was considered too large to be fully tested, a preliminary study was recommended to evaluate goodness of fit of the five distributions. Methods based on distributions with poor performance will be eliminated and the remaining methods fully tested and compared.

Body Height↗
PubMed2003

Maternal recall of exclusive breast feeding duration.

BACKGROUND: Both the pattern and duration of breast feeding are important determinants of health outcomes. In vertical HIV transmission research, reliable documentation of early breast feeding practices is important in order to correctly attribute postnatal transmission to feeding pattern. AIMS: To validate methods of collecting data on the duration of exclusive breast feeding (EBF) in an area of South Africa with a high HIV prevalence rate. METHODS: A total of 130 mothers were interviewed weekly, postnatally. At every interview a 48 hour and a seven day recall breast feeding history were taken. A subset of 70 mothers also received two intermediate visits per week during which additional 48 hour, non-overlapping, recall interviews were conducted. Ninety three infants were revisited at 6-9 months of age when mothers' recall of EBF duration from birth was documented. The different methods of recalling EBF status were compared against an a priori "best comparison" in each case. RESULTS: Reported breast feeding practices over the previous 48 hours did not reflect EBF practices since birth (specificity 65-89%; positive predictive value 31-48%). Six month EBF duration recall was equally poor (sensitivity at 2 weeks 79%; specificity 40%). Seven day recall accurately reflected EBF practices compared with thrice weekly recall over the same time period (sensitivity 96%, specificity 94%). CONCLUSIONS: 48 hour EBF status does not accurately reflect feeding practices since birth. Long term recall data on EBF are even more inaccurate. We recommend that data on duration of EBF be collected prospectively at intervals of no longer than one week.

Adult↗
PubMed2000

Growth response to recombinant human growth hormone (GH) in children with idiopathic growth retardation by level of maximum GH peak during GH stimulation tests.

Due to their lack of reproducibility, it is unlikely that GH stimulation tests can provide reliable diagnostic information to distinguish partial isolated GH deficiency (GHD) from idiopathic short stature (ISS). We hypothesized that the classical distinction between these groups, essentially based on stimulatory GH peaks, is artificial and that, as a consequence, the average response to GH treatment will not be different between them. The hypothesized lack of prognostic validity of stimulatory GH peaks was studied in 435 prepubertal children with nonorganic growth retardation. Children were categorized as 'severe GHD', 'partial GHD' or 'ISS', if the maximum rise in their serum GH during two GH stimulation tests was 0--10 mU/l, 10--20 mU/l, or >20 mU/l, respectively. Children with 'partial GHD' had short-term (1- and 2-year) and long-term (till final adult height) growth responses similar to those of children with ISS, significantly lower than the response seen in children with 'severe GHD'. In children with stimulatory GH peaks >10 mU/l, including those currently considered partially GH deficient, the maximum GH peak was not a significant determinant of growth response in the short or the long term. In conclusion, 'partial GHD' is ill defined and cannot be distinguished from ISS based on the currently applied auxological or GH stimulation test criteria alone. More research is required for better identification of (all) children who will respond to GH treatment, whether or not GH deficient.

Body Height↗
PubMed2000

Length velocity acceleration at 9 months of age in a representative birth cohort of Dutch infants.

According to the ICP (infancy-childhood-puberty) growth model, statural growth can be divided into three partially superimposed components assumed to represent different physiologic mechanisms. This model predicts a sudden acceleration of length velocity (LV) at the onset of the childhood component around 9 months. The existence of such an infancy-childhood growth spurt has not yet been firmly corroborated by epidemiological studies. In the present study length measurements were made at the target ages of 1, 3, 6, 9, 12, 15, 18 and 24 months in a birth cohort of 2034 infants. In order to check whether length growth showed a continuous smooth pattern, different mathematical models were fitted to the individual growth curves. The models included Count and Guo functions, 5th order polynomial and combinations of 5th order polynomial with the logarithmic term of the Count function and the square root term of the Guo function. We showed that in boys and girls there is a small but systematic lack of fit of the mathematical modeling, due to a sudden acceleration of LV around 9 months. In addition there was an increase in variation of attained length at this age. Comparison of unbalanced ANOVA models with and without addition of dummy variables for the target ages confirmed that there was an acceleration around 9 months that, if corrected for, leads to a significantly improved model fit (likelihood ratio test p < 0.0001). In absolute terms of LV, the misfit at 9 months was not greater than 0.5 cm/year on average. We conclude that the results of this study support the existence of a late infancy growth spurt. In our opinion, however, the magnitude of the phenomenon does not legitimate construction and use of discontinuous growth references such as the ICP reference.

Aging↗
PubMed1999

Interpretative difficulties with growth hormone provocative retesting in childhood-onset growth hormone deficiency.

A review of literature demonstrates that there are many ill-understood factors that determine the results of GH provocative (re)testing, so that these results should be interpreted with extreme caution when used for diagnosis or confirmation of diagnosis of GHD. GH provocation tests are probably of no value at all for what has been called 'partial GHD'. The phenomenon of 'normalization' of test results after long-term treatment with GH needs no 'transient GHD' hypothesis as it can be largely explained by the very low reproducibility of the tests and by a regression to the mean effect. Moreover, it is possible that 'normal values' increase with age. Other determinants of normal peak values may also change from childhood to adulthood and contribute to 'normalization'.

Adult↗
PubMed1999

Validity of height velocity as a diagnostic criterion for idiopathic growth hormone deficiency and Turner syndrome.

A deflecting growth curve over several years is sometimes the only indication for the possible presence of a growth disorder. In this study we looked at the potential diagnostic role of long-term downward deflection of the growth curve. It reports on the diagnostic validity of height velocity over 1, 2 or 3 years for isolated idiopathic growth hormone deficiency and for Turner syndrome in prepubertal children with a height that is still above -2.5 standard deviation scores (SDS). 1-year height velocity was found to have no diagnostic value because of an almost complete overlap of height velocity distributions with normal prepubertal children. However, height velocity over 3 years was found to have an acceptable validity in children 5-12 years old. In this age range a change in height SDS of -0.75 can be used as a valid criterion for further examination of karyotype and GH secretion capacity even if there are no other clear signs of a particular growth disorder.

Body Height↗
PubMed1999

Final height of growth hormone-treated GH-deficient children and girls with Turner's syndrome: the Dutch experience. The Dutch Advisory Group on Growth Hormone.

In the Dutch growth hormone (GH) registration database there are currently 552 GH-deficient children being treated, subcutaneously, with recombinant human GH six to seven times per week. Of those, 112 who have been treated for at least 2 years have reached final height. Mean age at start of therapy was 11.70 years. Mean GH dose was 15.5 IU/m(2) body surface per week. Mean final height was 173.2 cm (boys) and 159.7 cm (girls) and -1.36 SD of the population mean. Of the patients, 73.2% and 63.4%, respectively, reached a final height above -2 SD of the population or within target limits. FH-SDS was higher compared with the results of earlier cohorts with different treatment regimens. Target height, GH peak value at diagnosis, age at start of GH therapy, height SDS (HSDS) at start of puberty, and duration of GH therapy were significantly correlated with final height. These results, combined with those of a prospective GH dose-response study, suggest that better long-term results can be obtained with early and prolonged treatment and if the GH dose is individually adapted to the short-term growth response. In an ongoing dose-response study, 68 girls with Turner's syndrome, aged 2-11 years, were randomized into three dosage groups with a daily GH dose of: (group A) 4 IU/m(2) body surface; (group B) 4 IU/m(2) in the first year of therapy and 6 IU/m(2) thereafter; (group C) 4 IU/m(2) in the first year, 6 IU/m(2) in the second year, and 8 IU/m(2) thereafter. After 4 years of GH therapy, girls aged 12 years or older started low-dose oestrogen therapy. After 7 years of GH therapy, mean HSDS in all three groups had increased to values above the third percentile for healthy girls. Mean final height and final height gain of 25 girls was 159.1 and 12.5 cm, 161.8 and 14.6 cm, and 162.7 and 16.0 cm in groups A, B and C respectively. These long-term and final height results are more favourable than the results of earlier Dutch Turner's syndrome studies. Possible explanations are the higher GH doses and/or the younger age at start of GH therapy.

Adolescent↗
PubMed1998

Fatness and muscularity as risk indicators of child mortality in rural Congo.

OBJECTIVES: To examine the relationship of anthropometrical indicators of fatness and muscularity with mortality in children in a rural African community. BACKGROUND: A prospective cohort study was carried out in the rural health zone of Bwamanda, Northern Congo using a random cluster sample of 5167 children, aged 0-5 years. MAIN OUTCOME MEASURES: Short- and long-term mortality rates, being deaths within 3 months and deaths in 3-month periods observed 3-30 months after enrolment. Rates of all cause mortality and of mortality from kwashiorkor or marasmus, by level of baseline fatness and muscularity. Indicators of fatness and muscularity were obtained by correcting anthropometric arm fat and arm muscle areas for age, sex, weight and height. RESULTS: The relationship of both the fatness and muscularity scores with short-term mortality was marked by a clear threshold (-0.5 SDS) below which there was a significant rise in mortality from all causes as well as from kwashiorkor and marasmus. These excess mortalities were also found in normal weight children. Fatness and muscularity scores remained significant determining factors of short-term mortality in a multiple logistic regression analysis with sex, age, season and weight-for-age. A ROC curve analysis showed that fat and muscularity scores had better predictive abilities than weight-for-age. Low fat status had a bad prognosis on the long-term in underweight children. CONCLUSIONS: Measures of current nutritional status should not be based on weight indices alone. Objective and/or clinical evaluation of fat and muscle status (also in normal weight children) should be added in order to detect a higher proportion of malnourished children and to more accurately evaluate mortality risk.

Adipose Tissue↗
PubMed1998

Body mass index in growth hormone deficient children before and during growth hormone treatment.

Growth hormone deficiency (GHD) is associated with truncal obesity. We aimed at identifying factors that determine the body mass index (BMI) of untreated GHD children and the changes in BMI during 2 years of GH therapy in 348 Dutch GHD children registered in the National GH Registration Database. BMI was expressed as a standard deviation score (SDS). Before GH therapy, the mean (95% CI) BMI-SDS in all GHD children (0.09 (-0.05 to 0.24) SDS) was comparable to normal children. Patients with GHD due to a cranial tumour have a higher BMI (1.03 (0.69-1.36) SDS; p < 0.0001) as well as those with multiple pituitary hormone deficiencies (0.35 (0.14-0.57) SDS; p = 0.005) and patients who are in puberty at start of GH therapy (0.60 (0.13-1.08) SDS; p = 0.036). During GH therapy BMI initially decreased to reach a nadir of -0.28 (-0.35 to -0.21) SDS at 6 months. Thereafter BMI progressively increased to -0.09 (-0.18 to -0.04) SDS after 24 months. A higher initial BMI-SDS resulted in a larger decrease in BMI-SDS. We showed that this can be sufficiently explained by a regression to the mean effect.

Age Factors↗
PubMed1997

Anthropometry and body composition in children.

Changes in body fat, fat-free mass and extracellular water occur in many disorders, and during normal growth in children. Thus, body composition is an increasingly important measurement in paediatric clinical practice, and is used for diagnostic purposes, for decisions for treatment and for monitoring improvement. A number of different methods exist for determining body composition in children; however, their use is complicated by the absence of a gold standard and the lack of validity data in children both with and without growth disorders. In this report, validity and usefulness are compared among anthropometric methods and weighted against other techniques used in children. Recent recommendations of a number of expert committees are discussed.

Adipose Tissue↗
PubMed1996

Final height and hormonal function after bone marrow transplantation in children.

AIM: To analyze final height and hormonal function in long-term survivors of bone marrow transplantation (BMT). PATIENTS: Group 1 consisted of 16 patients (10 boys) with a hematologic malignancy, mostly leukemia, conditioned for BMT with total body irradiation (TBI), 7.5 to 12 Gy, and cyclophosphamide. Group 2 consisted of 14 patients (9 boys) with severe aplastic anemia, conditioned with chemotherapy only. RESULTS: In group 1, patients achieved a reduced final height after BMT. The difference between the height standard deviation score (SDS) at BMT and the height SDS at final height was -1.96 (0.82) SDS in boys and -0.92 (0.71) SDS in girls (p = 0.0001, and p = 0.02 respectively). Final height was also lower than target height (boys, p = 0.01; girls, p = 0.03). Prepubertal growth in the first 3 years after BMT was normal but pubertal height gain was decreased. The patients in group 2 achieved normal height. Thyroid function and adrenal function were normal in all patients, and no growth hormone deficiency was detected. Serum follicle-stimulating hormone values after BMT were increased in all group 1 patients, with return to normal in two patients. Serum luteinizing hormone values were increased in all group 1 girls, with recovery in one girl. Normal serum luteinizing hormone values and spontaneous puberty were found in all group 1 boys. In group 2, disturbances in gonadotropins were seen only in three boys and two girls. CONCLUSION: In patients treated in childhood with BMT after chemotherapy and TBI with 7.5 Gy or more, final height is compromised because of blunted growth in puberty. Patients who had not received TBI suffered no height loss. In the majority of patients, the combination of chemotherapy and TBI also resulted in irreversible disturbances of gonadal function.

Adolescent↗
PubMed1996

Maternal determinants of child survival in a rural African community.

BACKGROUND: The aim was to determine maternal factors related to child survival in the rural area of Bwamanda, Northern Zaire. METHODS: A prospective study of 30-months mortality was carried out in a cohort of 776 children aged 0-3 months, obtained by random cluster sampling. Inclusion criteria were exclusive breastfeeding, no severe prematurity and absence of severe protein-energy malnutrition, diarrhoea or acute respiratory infection. Mortality was recorded by regular home visits and inspection of hospital and funeral registers. Maternal factors that remain stable during follow-up were studied. RESULTS: Factors associated with excess mortality in bivariate and multiple logistic regression analysis were: (i) mother has parity > 5 (relative risk [RR] = 1.5-4.2); (ii) distance from the health centre > 5 km (RR = 0.9-2.9); (iii) invaliding maternal diseases (RR = 1.2-9.0). Maternal school education (conditional odds ratio [OR] = 1.0-5.0) was significant in the multiple regression. In contrast to the other risk factors, mother-child separation or problems with breastfeeding were rare and did not significantly increase mortality. CONCLUSIONS: Chronic stress situations created by maternal invalidity, high parity and distance from health care facilities, increase child mortality. Acute stress in the mother-child dyad seemed to be efficiently compensated for. In subsistence economy areas, maternal school education can be a disadvantage.

Adolescent↗
PubMed1996

Validity of single-weight measurements to predict current malnutrition and mortality in children.

In this cross-sectional study of a random cluster sample of 4238 rural Zairian children aged 0-5 y, we assessed underweight and wasting, defined as weight-for-age < 75%, and weight-for-height < 80% of the U.S. National Center for Health Statistics reference median, respectively. We determined the diagnostic validity of underweight and wasting for protein-energy malnutrition, taking a low arm circumference and clinical signs of muscle loss as criteria. Both underweight and wasting had low sensitivity in recognizing low arm circumference, any clinical muscle loss and even severe marasmus, especially in the weaning period of 12-30 mos. Receiver operating characteristic (ROC) analysis showed that the diagnostic validity of weight-for-height can be improved by using a cutoff for wasting at Z-score -0.75 instead of Z-score -2 or 80% of reference median. ROC analysis of 30-mo mortality revealed a poor prognostic validity of weight-for-height and weight-for-age and better performances of arm circumference (cm) and of age. These data suggest that nutritional intervention programs targeted at wasted or underweight children can have only a limited effect on the prevalence of protein-energy malnutrition in the community or on the long-term mortality associated with it.

Age Distribution↗
PubMed1996

Body weight in children with Turner syndrome treated with growth hormone.

OBJECTIVE: As overweight is a major concern in many children with Turner syndrome, we studied the effect of growth-promoting treatment with human growth hormone (hGH) on body weight indices. DESIGN: Longitudinal study of the effect of hGH on weight indices over time in a cohort of Turner girls of different ages. SUBJECTS: An index group of 199 hGH treated girls and a reference group of 569 untreated girls. METHODS: Turner-specific weight-for-age, weight-for-height and body mass index-for-age (BMI) values were computed. In order to take account of regression to the mean, we studied spontaneous changes of these variables in the reference group. References for spontaneous changes over 3, 6, 12 or 24 months were constructed. Observed changes in the index group were corrected by subtracting the expected spontaneous change. Corrected changes were compared between overweight, normal and underweight children. RESULTS: Treatment with hGH leads to a temporary decrease of weight indices during the first six months. This decreasing effect was not seen in overweight children. Treatment increases BMI in overweight children over 24 months, but not in normal or underweight children. BMI at start of hGH treatment did not modify long-term growth response. CONCLUSION: hGH treatment does not help to improve BMI in Turner syndrome children with a tendency to overweight.

Adolescent↗
PubMed1995

Final height after long-term growth hormone treatment in Turner syndrome. European Study Group.

OBJECTIVES: To study final height after long-term growth hormone (GH) treatment in girls with Turner syndrome (TS). PATIENTS: One hundred fifty three patients with TS, participating in five European trials, were included. They started GH treatment in 1987-1989 at an age of 10 years or older. Mean age at start of treatment ranged between 11.7 and 14.6 years among countries and mean bone age between 9.4 and 11.8 years. Fourteen girls were lost to follow-up, leaving 139 for analysis. Most girls have now attained final height (FH), defined as a linear growth velocity (GV) of 4 mm/yr or less, measured over at least 6 months (group 1, n = 56), or near-FH, defined as a GV of 5 to 9 mm/yr (group 2, n = 22). Sixty-one girls were still growing 10 mm/yr or more. METHODS AND MAIN RESULTS: At the last measurement, mean (SD) height was 150.7 (4.9) cm in group 1 and 148.5 (5.1) cm in group 2. The differences between FH and projected final height based on extrapolation of the initial height-standard deviation score on Turner syndrome reference values, were 2.9 (3.8) and 3.0 (3.3) cm, respectively. The mean gain over the Bayley-Pinneau prediction of FH was 3.3 (3.9) cm in both groups. No significant differences between countries were found. The range of gains over projected height (-4.7 to 12.1 cm) was large, and 25% of gains were 5 cm or more. Gain over initial projection was strongly related to initial growth delay and to growth response during the first 2 years of treatment. A logistic regression model is presented that predicts gain of more than 5 cm with a positive predictive value of 62% and a negative predictive value of 84%. CONCLUSIONS: Long-term GH treatment in girls with TS, starting treatment at a relatively advanced age ( > 10 years) resulted in a modest mean gain in FH of 3 cm, with wide interindividual variation.

Adolescent↗