Prenatal smoking exposure and offspring stress coping in late adolescence: No causal link

Ralf Kuja-Halkola (1, 2) , B d'Onofrio (3) , Anastasia Nyman Iliadou (1) , Niklas Langstrom (1, 2) , Paul Lichtenstein (1)

1 MEB - Department of Medical Epidemiology and Biostatistics
2 Centre for Violence Prevention
3 Department of Psychological and Brain Sciences

Background: In utero exposure to tobacco smoking has been suggested to cause persistent alterations in cognitive functioning. We examined if mothers' smoking during pregnancy (SDP) is associated with long term impairment in offspring stress-coping and the causal mechanism behind a possible link. Methods: We used a large cohort (n=187 106) of young males in Sweden (mean age=18.2 years), who underwent a semi-structured psychological assessment in 1997 to 2006, including an evaluation of stress-coping ability, as part of the compulsory military conscript examination. We compared differentially exposed siblings within nuclear families and cousins in extended families and used multilevel structural equation models to disentangle genetic from environmental contributions to the association between SDP and stress-coping. Results: SDP and offspring stress-coping was moderately strongly associated when comparing unrelated individuals (regression coefficient (b)=-0.38 on a 9-grade scale; 95% confidence interval (CI), -0.40 - -0.36, p-value<0.0001). In contrast, it disappeared when siblings were compared (b=0.11; 95% CI, -0.01 - 0.23, p-value=0.071). This familial confounding was entirely due to genetic influences. Conclusions: SDP is an established risk factor for pregnancy- and birth-related complications. However, we found no long-term effect of SDP on offspring stress-coping. Rather, the observed association was due to familial confounding of genetic origin; women prone to SDP also transmit genes to their children that are associated with poorer coping with stress.

Mots clés: Medicine

Ralf Kuja-Halkola, B d'Onofrio, Anastasia Nyman Iliadou, Niklas Langstrom, Paul Lichtenstein. Prenatal smoking exposure and offspring stress coping in late adolescence: No causal link. International Journal of Epidemiology, 2010, 39 (6), pp.1531. ⟨10.1093/ije/DYQ133⟩. ⟨hal-00614850⟩