A Quasi-Experimental Study of Maternal Smoking During Pregnancy and Offspring Academic Achievement

Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA.
Child Development (Impact Factor: 4.92). 01/2010; 81(1):80-100. DOI: 10.1111/j.1467-8624.2009.01382.x
Source: PubMed


The current study, based on all births in Sweden from 1983 to 1991 (N = 654,707), explored the processes underlying the association between smoking during pregnancy (SDP) and offspring school grades and mathematic proficiency at age 15. The analyses compared relatives who varied in their exposure to SDP and who varied in their genetic relatedness. Although SDP was statistically associated with academic achievement (AA) when comparing unrelated individuals, the results suggest that SDP does not cause poorer academic performance, as full siblings differentially exposed to SDP did not differ in their academic scores. The pattern of results suggests that genetic factors shared by parents and their offspring help explain why offspring exposed to SDP have lower levels of AA.

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Available from: Niklas Långström
    • "The registers were: (1) the Medical Birth Register, which provides detailed birth information for more than 95% of pregnancies in Sweden beginning 1 January 1973 (Swedish Centre for Epidemiology, 2003), as well as offspring antenatal and perinatal information ; (2) the Multi-Generation Register, which can be used to determine biological and adoptive familial relationships for all individuals born after 1932 or have been living in Sweden since 1961 (Statistics Sweden, 2010); (3) the Statistics Sweden Regional Register (SSRS), which records an annual dichotomous change in residence beginning in 1983 (Statistics Sweden, 2013); (4) the Integrated Database for Labor Market Research (LISA), which provides longitudinal market labor information (e.g. income level, marital status, unemployment status, social welfare status, disability status, etc.) on all individuals over the age of 16 beginning in 1990 until the end of 2008, as well as an annual count of residential changes (Statistics Sweden, 2011); (5) the Cause of Death Register, which contains the date and contributing cause(s) of deaths since 1 January 1952 (Statistics Sweden, 2010); (6) the National Patient Register, which includes International Classification of Diseases Eighth, Ninth, and Tenth Revisions (ICD-8, ICD-9, ICD-10) codes (Janssen & Kunst, 2004) and dates for hospital inpatient admissions since 1 January 1969 (Jacobsson, 2009); (7) the Migration Register, which records dates for immigrations to and emigrations from Sweden since 11 September 1901 (Statistics Sweden, 2010); (8) the National Crime Register, which records all criminal convictions (i.e. for both non-violent and violent offenses), the date, and the sentence since 1 January 1973 for all citizens aged 515 years (Fazel & Grann, 2006); (9) the Education Register, which includes information since 1970 on the highest level of completed formal education, divided into seven ordinal groups from fewer than 9 years of education to postgraduate education (D'Onofrio et al. 2010); and (10) the National School Register, which includes a continuous measure of academic performance aggregated across 16 subjects since 1989, and Swedish language tests since 1987 for all students graduating from 9th grade at approximately age 16 years (the Swedish National Agency for Education, 2011). Additional information about the registers can be found elsewhere (e.g. "
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    ABSTRACT: Background Given the frequency with which families change residences, the effects of childhood relocations have gained increasing research attention. Many researchers have demonstrated that childhood relocations are associated with a variety of adverse outcomes. However, drawing strong causal claims remains problematic due to uncontrolled confounding factors. Method We utilized longitudinal, population-based Swedish registers to generate a nationally representative sample of offspring born 1983–1997 (n = 1 510 463). Using Cox regression and logistic regression, we examined the risk for numerous adverse outcomes after childhood relocation while controlling for measured covariates. To account for unmeasured genetic and environmental confounds, we also compared differentially exposed cousins and siblings. Results In the cohort baseline model, each annual relocation was associated with risk for the adverse outcomes, including suicide attempt [hazard ratio (HR) 1.19, 95% confidence interval (CI) 1.19–1.20]. However, when accounting for offspring and parental covariates (HR 1.08, 95% CI 1.07–1.09), as well as genetic and environmental confounds shared by cousins (HR 1.07, 95% CI 1.05–1.09) and siblings (HR 1.00, 95% CI 0.97–1.04), the risk for suicide attempt attenuated. We found a commensurate pattern of results for severe mental illness, substance abuse, criminal convictions, and low academic achievement. Conclusions Previous research may have overemphasized the independent association between relocations and later adverse outcomes. The results suggest that the association between childhood relocations and suicide attempt, psychiatric problems, and low academic achievement is partially explained by genetic and environmental confounds correlated with relocations. This study demonstrates the importance of using family-based, quasi-experimental designs to test plausible alternate hypotheses when examining causality.
    No preview · Article · Dec 2015 · Psychological Medicine
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    • "However, a more rigorous sibling analysis, which considered unaccounted socioeconomic and familial characteristics and controlled for temporal confounding, reduced this association. Our results are analogous to other sibling design studies concluding that the relationship between maternal SDP and psychiatric or cognitive outcomes observed in conventional analyses is largely due to familial unaccounted residual confounding [12], [13], [14], [15], [16], [17]. Our findings also support the conclusion of Lavigne et al questioning the role of maternal SDP as a risk factor for psychopathology in children [6]. "
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    ABSTRACT: A recent population-based, longitudinal study from Finland observed a dose-response association between smoking during pregnancy (SDP) and use of psychotropic medications in exposed children and young adults. However, this association may be confounded by unmeasured familial characteristics related to both SDP and offspring mental health. Consequently, we aim to investigate the effect of SDP by means of a sibling design that to some extent allows controlling for unknown environmental and genetic confounders. Using the Swedish Medical Birth Register (1987-1993), which was linked to the Swedish Prescribed Drugs Register (July 2005-December 2008), we investigated 579,543 children and among them 39, 007 were discordant for use of psychotropic medication and 4,021 siblings discordant for both use of psychotropic medication and for smoking exposure. Replicating the Finnish study using traditional logistic regression methods we found an association between exposure to ≥10 cigarettes per day during pregnancy and psychotropic drug use (odds ratio = 1.61, 95% confidence interval 1.56, 1.66). Similar in size to the association reported from Finland (odds ratio = 1.63; 95% confidence interval 1.53, 1.74). However, in the adjusted sibling analysis using conditional logistic regression, the association was considerably reduced (odds ratio 1.22; 95% confidence interval 1.08, 1.38). Preventing smoking is of major public health importance. However, SDP per se appears to have less influence on offspring psychotropic drug use than previously suggested.
    Full-text · Article · May 2013 · PLoS ONE
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    • "D'Onofrio et al. (2010) examine the long-term consequences on academic achievement for children whose mothers smoked during pregnancy, with the important finding that the supposed prenatal environmentally mediated effects are probably largely a function of a shared genetic liability. Price et al. (2010) demonstrate an important gene by environment mechanism for understanding the effects on intrauterine growth, and D'Onofrio et al. (2010) examine the long-term consequences on academic achievement for children whose mothers smoked during pregnancy, with the important finding that the supposed prenatal environmentally mediated effects are probably largely a function of a shared genetic liability. Davis and Sandman (2010), using data from an ongoing longitudinal study, found that the timing of cortisol levels during gestation were associated with differences in the babies' developmental level at 12 months. "

    Preview · Article · Jan 2010 · Child Development
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