07, p = .075). The magnitude of the indirect effects that achieve statistical significance ranges from 1.04 to 1.09; in comparison, the magnitude of the direct effects range from 1.6 to 3.1. Hence, the mediation effects are small, relative to the total effect. Discussion selleckchem Vorinostat In the research reported in this paper, we investigated whether the relationship between maternal smoking behavior before, during, and after pregnancy and child smoking trajectory class was partially mediated by problem behavior in middle childhood. We found some evidence for a partially mediated relationship, for two groups of children exposed to maternal smoking��those whose mothers smoked during pregnancy, and continued to smoke, and those whose mothers quit while pregnant and then resumed smoking after the birth of the child, and did not quit.

The effects from two patterns of maternal smoking to child smoking class were found to be partially mediated by problem behavior. The two groups of mothers where the partial mediation was found were those who smoked after pregnancy��specifically, the ��not SDP, then relapse�� group and the SDP and continue after pregnancy group. This result provides little evidence to support a simple mediation hypothesis of prenatal exposure; that is, that tobacco smoke introduces physiological change, which causes increase in problem behavior, manifesting itself as smoking. However, this does not rule out the possibility of more complex processes than we have modeled, for example, those of cumulative exposure or threshold effects (Singh-Manoux, 2005).

These results might suggest a mechanism in which continued maternal smoking after pregnancy is related to problem behavior, later manifesting as smoking. This mechanism is possibly a factor, which is predictive of initiation (or perhaps reinitiation) of smoking in both mothers and their offspring. The mechanism may be a genetic predisposition to smoking or may be a feature of the shared environment, which is associated with problem behavior in children and maternal smoking, such as family or environmental stress or sand family values, beliefs, or norms. In addition, there may be interactions with other substances, for example, alcohol. We believe that this study is the first to investigate mediators of the effect of maternal smoking during pregnancy using population-representative data and latent classification techniques.

That mediation effects from smoking during pregnancy were not detected suggests that although problem behavior is associated with maternal smoking patterns, smoking in children is not a manifestation of this problem behavior. Several limitations should be borne in mind. The smoking reports were all collected by self-report, which may be prone to bias due because respondents do not want to Cilengitide admit to smoking or simply because they forget.