Biomedical subjects

M Danckaerts

Publications and source records attributed to M Danckaerts.

9 recordsLinked to original sources

PubMed2002

Prenatal life and post-natal psychopathology: evidence for negative gene-birth weight interaction.

BACKGROUND: Many studies suggest that pregnancy and birth complications (PBCs) are environmental risk factors for child psychopathology. However, it is not known whether the effects of PBCs occur independently of genetic predisposition. The current study examined the possibility of gene-environment interaction in a twin design. METHOD: The East Flanders Prospective Twin Survey prospectively records the births of all twin pairs born in East Flanders, Belgium. The current study included 760 twin pairs aged 6-17 years. Multilevel regression analysis was used to assess the effects of several PBCs collected around the time of birth. Using structural equation modelling, ACE models assuming additive genetic (A), shared environmental (C) and unique environmental (E) influences, were compared in order to examine whether the contribution of genetic factors to parent-rated child problem behaviour varied as a function of exposure to dichotomously and continuously defined PBCs. RESULTS: A main independent effect of lower birth weight, corrected for gestational age (small for gestational age--SGA), on child problem behaviour was found. In addition, there was an interaction between genetic influence and SGA, in that being smaller for gestational age resulted in less influence of additive genetic factors on individual differences in problem behaviour. CONCLUSIONS: Results are suggestive of negative gene-birth weight interaction. Children who are SGA are less sensitive to the genetic effects, and those with high genetic vulnerability are less sensitive to the effects of being SGA in bringing about post-natal mental health effects.

Adolescent↗

PubMed2002

Child psychopathology and lower cognitive ability: a general population twin study of the causes of association.

Previous work has demonstrated associations between lower cognitive ability and childhood and adult non-psychotic psychopathology. As both cognitive ability (CA) and child psychopathology (CP) are influenced by genetic factors, one explanation for the association is that they are the pleiotropic manifestations of the same underlying genetic factors. The present paper examines three possible causes of the association: additive genetic factors, common environmental factors and individual-specific environmental factors. Three hundred and seventy-six twin pairs from the East Flanders Prospective Twin Survey were examined with the Child Behaviour Checklist and the Wechsler Intelligence Scale for Children-Revised. The cross-twin within-variable, within-twin cross-variable and cross-twin cross-variable correlations were calculated. Using structural equation modelling, bivariate models were fitted. The best fitting model was chosen, based on likelihood and parsimony. The observed phenotypic correlation between CP and CA was -0.19 (95% CI: -0.09, -0.27), with genetic factors accounting for about 84% of the observed correlation. Bivariate model fitting quantified the genetic correlation between CP and CA at -0.27 (95% CI: -0.12, -0.42) and the individual-specific environmental correlation at -0.17 (95% CI: -0.03, -0.31). In children, three different genetic factors may exist: one that solely affects the liability to CP, one that has only an effect on CA and one that influences both CP and CA. While individual-specific environmental factors can influence the liability to both traits, our results suggest that most of the environmental factors that increase the risk of CP do not influence CA and vice versa.

Adolescent↗

PubMed2001

A prospective twin study of birth weight discordance and child problem behavior.

BACKGROUND: We investigated whether low birth weight constitutes a causal risk factor for child problem behavior, using a variation of the co-twin control method. METHODS: In a representative sample of 745 twin pairs (monozygotic: 324 pairs), birth weight was recorded at birth and child problem behavior at mean age 10 years was measured with the Child Behaviour Checklist (CBCL). RESULTS: Lower birth weight was a continuous risk factor for later child problem behavior (adjusted regression coefficient over units of 500 g: beta = -.15, p =.046), and greater levels of within-pair CBCL discordance did not result in a reduced effect size. Greater within-pair birth weight discordance was associated with greater within-pair CBCL score discordance (beta =.35, p <.001). This latter effect was similar in monozygotic (beta =.34, p =.005) and dizygotic twins (beta =.37, p =.003). CONCLUSIONS: The fact that (1) the effect size of the association between low birth weight and child problem behavior was not reduced in pairs with greater levels of CBCL discordance, and (2) similar effect sizes were found in monozygotic and dizygotic twins for the within-pair association between birth weight discordance and CBCL score discordance, suggests that the observed relationship between low birth weight and child problem behavior is not due to a shared environmental or genetic variable that influences both characteristics. Lower birth weight is a causal risk factor for child problem behavior, the effects of which may well extend into adulthood.

Adolescent↗

PubMed2001

Modelling bivariate ordinal responses smoothly with examples from ophthalmology and genetics.

A non-parametric implementation of the bivariate Dale model (BDM) is presented as an extension of the generalized additive model (GAM) of Hastie and Tibshirani. The original BDM is an example of a bivariate generalized linear model. In this paper smoothing is introduced on the marginal as well as on the association level. Our non-parametric procedure can be used as a diagnostic tool for identifying parametric transformations of the covariates in the linear BDM, hence it also provides a kind of goodness-of-fit test for a bivariate generalized linear model. Cubic smoothing spline functions for the covariates are estimated by maximizing a penalized version of the log-likelihood. The method is applied to two studies. The first study is the classical Wisconsin Epidemiologic Study of Diabetic Retinopathy. The second study is a twin study, where the association between the elements of twin pairs is of primary interest. The results show that smoothing on the association level can give a significant improvement to the model fit.

Adolescent↗

PubMed2001

Associations between nonshared environment and child problem behaviour.

BACKGROUND: Twin studies suggest that environmental effects on the development of child psychopathology largely involve nonshared environmental processes. However, the influence of the nonshared environment may have been overestimated, as the relationship between environment and behaviour may be genetically mediated. A direct measure of the nonshared environment (using the Sibling Inventory of Differential Experience - SIDE) was investigated in relation to child psychopathology, and tested for possible genetic mediation. METHOD: Parent-rated versions of the Child Behaviour Checklist (CBCL) and the SIDE were collected in 760 twin pairs aged 6-17 years. Multilevel regression analysis was used to assess the influence of SIDE scores on CBCL total problem scores, internalising symptoms, externalising symptoms and depressive symptom scores. Genetic mediation was assessed by examining interaction with zygosity in the association between SIDE scores and differences in CBCL scores (absence of interaction indicating no genetic mediation). RESULTS: The results revealed significant associations between SIDE dimensions on the one hand, and degree of internalising, externalising, depression and total symptom scores on the other. However, the effects were non-linear, and especially apparent for the extremes of differential environmental experience within twin pairs. Overall, there was no strong evidence for genetic mediation of associations between nonshared environment and symptoms. CONCLUSIONS: Direct, genetically unconfounded but skewed relationships may exist between nonshared environment on the one hand and behavioural differences on the other, although longitudinal data are necessary to determine the direction of effects.

Adolescent↗

PubMed2000

A natural history of hyperactivity and conduct problems: self-reported outcome.

At the age of 16-18 years, outcome was prospectively assessed in a general population sample of four behavioural groups, defined at 6-7 year old: a pure pervasively hyperactive group (N = 31), a mixed hyperactive conduct problem group (N = 20), a pure conduct problem group (N = 18) and a normal control group (N = 29). The objective of the present paper is to describe outcome in those domains for which self-report is recognised as a valid source of information. Differential effects for hyperactivity and conduct problems on outcome were studied. It was found that early hyperactivity and conduct problems predicted different patterns of conduct problems in adolescence. Drug use in adolescence was not predicted by either type of behavioural problem in childhood. Overall social adjustment was worse in the hyperactive groups, whereas no differences in self-esteem were found. Hyperactivity was a strong predictor of relationships problems in adolescence. The results suggest that hyperactivity and conduct problems in childhood are differential predictors of outcome in adolescence.

Adolescent↗

PubMed1999

Hyperactivity and reading disability: a longitudinal study of the nature of the association.

In order to investigate the possible causal relationships between hyperactivity and educational underachievement that might account for their frequent co-occurrence, four groups of boys, defined by the presence or absence of hyperactivity and specific reading retardation, were identified in an epidemiological study of 7 8-year-old children. They were examined in detail by means of parental interviews and psychological tests and reassessed 9 years later at the age of 16-18 years on a similar range of measures. The findings provided little support for the idea that persistent reading disabilities either lead to the development of hyperactivity de novo or increased the likelihood that hyperactivity, when present, would persist. Similarly, although features of hyperactivity persisted to follow-up, there was little evidence that they either lead to the development of reading disabilities or increased the likelihood that reading disabilities, when present, would persist. Socioeconomic adversity and a history of speech therapy were more common in the group with both hyperactivity and reading disability, but the strength of these associations made it unlikely that these factors could account for the frequent co-occurrence of the two conditions.

Adolescent↗

PubMed1996

Hyperactivity and conduct problems as risk factors for adolescent development.

OBJECTIVE: To clarify the developmental risk associated with hyperactive behavior, especially the relationship between hyperactive and conduct problems, in a longitudinal epidemiological design. METHOD: A follow-up study of children who were identified, by parent and teacher ratings in a large community survey of 6- and 7-year-olds, as showing pervasive hyperactivity or conduct problems or the comorbid mixture of both problems or neither problem. They were later investigated, at the age of 16 to 18 years, with detailed interview techniques as well as parental and self-report ratings and cognitive tests. RESULTS: Hyperactivity was a risk factor for later development, even allowing for the coexistence of conduct problems. Its sequelae included a high likelihood of psychiatric diagnosis, persisting hyperactivity, violence and other antisocial behaviors, and social and peer problems. CONCLUSIONS: The results suggested a developmental pathway through which hyperactivity raised the likelihood of impaired social adjustment, including the development of psychiatric disorders, independently of the existence of conduct problems.

Adolescent↗

PubMedDate not supplied

Self-report of attention deficit and hyperactivity disorder in adolescents.

The validity of self-report measurement varies widely according to the type of behaviour investigated. For behaviour of overactivity and inattention, adolescents seem to underestimate their problems. Well validated instruments for self-report of attention deficit and hyperactivity disorder (ADHD) are lacking yet, and research on ADHD beyond childhood relies quite heavily on self-report. In this study, an attempt is made to validate an adolescent interview scale for DSM-based ADHD symptoms. Results show that the measure has a high inter-rater reliability and is a good predictor of general outcome. However, adolescents do not validly report on symptoms specifically of ADHD. Possible implications for research and clinical practice are formulated.

Adolescent↗