Smoking during pregnancy and attention-deficit/hyperactivity disorder, predominantly inattentive type: a case-control study.
OBJECTIVE
Few previous studies assessed specifically attention-deficit/hyperactivity disorder, predominantly inattentive subtype (ADHD-I) in nonreferred samples. This study investigated the association between ADHD-I and prenatal exposure to nicotine.


METHODS
In a case-control study performed between September 2002 and April 2005, we assessed a nonreferred Brazilian sample of 100 children and adolescents with ADHD-I and 100 non-ADHD controls (6-18 years old). Cases and controls, matched by gender and age, were screened using teacher reports in the Swanson, Nolan, and Pelham-IV (SNAP-IV) scale. They were systematically evaluated through structured diagnostic interviews. Prenatal exposure to nicotine and potential confounding factors were evaluated by direct interview with mothers.


RESULTS
Adjusting for confounding factors (maternal ADHD, oppositional defiant disorder, birth weight, and alcohol use during pregnancy), children whose mothers smoked>or=10 cigarettes per day during pregnancy presented a significantly higher odds ratio for ADHD-I than children who were not exposed to nicotine during pregnancy (odds ratio 3.44; 95% confidence interval 1.17-10.06). Dimensional analyses showed significantly higher inattentive scores in subjects whose mothers smoked>or=10 cigarettes per day than in others after adjusting for confounding factors (p=.002).


CONCLUSIONS
In a nonreferred sample, the authors expanded to ADHD-I previous findings documenting the association between prenatal exposure to nicotine and broadly defined ADHD in clinical samples.
Schmitz
Marcelo
M
Dr. Schmitz, Denardin, Silva, Pianca, Hutz, and Rohde are with the Federal University of Rio Grande do Sul, Brazil; Dr. Faraone is with Upstate Medical University, Syracuse, NY.
Denardin
Daniel
D
Dr. Schmitz, Denardin, Silva, Pianca, Hutz, and Rohde are with the Federal University of Rio Grande do Sul, Brazil; Dr. Faraone is with Upstate Medical University, Syracuse, NY.
Laufer Silva
Tatiana
T
Dr. Schmitz, Denardin, Silva, Pianca, Hutz, and Rohde are with the Federal University of Rio Grande do Sul, Brazil; Dr. Faraone is with Upstate Medical University, Syracuse, NY.
Pianca
Thiago
T
Dr. Schmitz, Denardin, Silva, Pianca, Hutz, and Rohde are with the Federal University of Rio Grande do Sul, Brazil; Dr. Faraone is with Upstate Medical University, Syracuse, NY.
Hutz
Mara Helena
MH
Dr. Schmitz, Denardin, Silva, Pianca, Hutz, and Rohde are with the Federal University of Rio Grande do Sul, Brazil; Dr. Faraone is with Upstate Medical University, Syracuse, NY.
Faraone
Stephen
S
Dr. Schmitz, Denardin, Silva, Pianca, Hutz, and Rohde are with the Federal University of Rio Grande do Sul, Brazil; Dr. Faraone is with Upstate Medical University, Syracuse, NY.
Rohde
Luis Augusto
LA
Dr. Schmitz, Denardin, Silva, Pianca, Hutz, and Rohde are with the Federal University of Rio Grande do Sul, Brazil; Dr. Faraone is with Upstate Medical University, Syracuse, NY.. Electronic address: lrohde@terra.com.br.
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology*; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012907:Smoking