Child Care, Socio-economic Status and Problem Behavior: A Study of Gene–Environment Interaction in Young Dutch Twins

Abstract

The influences of formal child care before age 4 on behavioral problems at 3, 5, and 7 years of age were assessed in 18,932 Dutch twins (3,878 attended formal child care). The effect of formal child care was studied on the average level of problem behavior and as moderator of genetic and non-genetic influences, while taking into account effects of sex and parental socio-economic status (SES). There was a small association between attending formal child care and higher externalizing problems, especially when SES was low. Heritability was lower for formal child care and in lower SES conditions. These effects were largest at age 7 and for externalizing problems. In 7 year-old boys and girls, the difference in heritability between the formal child care group of low SES and the home care group of high SES was 30% for externalizing and ~20% for internalizing problems. The decrease in heritability was explained by a larger influence of the environment, rather than by a decrease in genetic variance. These results support a bioecological model in which heritability is lower in circumstances associated with more problem behavior.

Comparing the genetic architecture of childhood behavioral problems across socioeconomic strata in the Netherlands and the United Kingdom

“…One strength of this study is that we applied thresholds to take the skewed distribution of childhood behavioral problems into account. Studies so far on the moderating effect of SES on the genetic architecture of childhood behavioral problems included childhood behavioral problems as a continuous variable [20,37]. Because of the non-normal distribution of childhood behavioral problems, analyzing behavioral problems continuously might lead to overestimated genetic variance and underestimated shared environmental variance.…”

“…In addition, twin studies have shown that the contribution of genetic and environmental factors to individual differences in childhood behavioral problems varies across SES strata, indicating a moderator effect of SES on the genetic architecture of childhood behavioral problems. For example, research in children from the Netherlands [20] and research on adolescents from Sweden [21] report lower heritability, higher influence of the shared environment, and lower influence of the nonshared environment on behavioral problems in children from lower SES families compared to children from higher SES families. These findings suggest that the influence of shared environmental factors is amplified in disadvantageous environments, such as low SES, or reduced by advantageous environments.…”

Genetic Vulnerability to Experiencing Child Maltreatment

“…Most often, child victimization is, in itself, conceptualized as an environmental risk factor for other detrimental outcomes, such as psychopathology (e.g., McCrory et al, 2012). In this context, genes have been shown to provide increased susceptibility to the harmful effects of child maltreatment, a phenomenon described as gene–environment interaction (GxE; e.g., Duncan and Keller, 2011; Middeldorp et al, 2014). Genes have also been found to provide a mechanism for these harmful effects, via changes in gene expression (i.e., epigenetic changes; e.g., Weaver et al, 2004).…”

Estimating the Heritability of Experiencing Child Maltreatment in an Extended Family Design

“…Research on cognitive abilities has associated low SES with smaller genetic influences ( Bates, Lewis, & Weiss, 2013 ) and greater shared environmental effects ( Tucker-Drob, Rhemtulla, Harden, Turkheimer, & Fask, 2011 ). Similarly, the social push perspective suggests that genetic effects may be suppressed in high-risk environments ( Middeldorp et al, 2014 ; Raine, 2002 ). In the context of gene-by-environment interaction, it becomes clear that the importance of understanding the heritability of maltreatment goes beyond providing an etiological framework.…”