title: Nonverbal Reasoning in Preschool Children: Investigating the Putative Risk of Secondhand Smoke Exposure and Attention-Deficit/Hyperactivity Disorder as a Mediator.
abstract: BACKGROUND
  Exposure to secondhand smoke (SHS) has been found to be associated with cognitive deficits in children. However, relatively little is known about the relationship between SHS exposure, cognitive deficits, and smoking-related psychopathology, specifically attention-deficit/hyperactivity disorder (ADHD) and externalizing disorders such as conduct disorder (CD) and oppositional defiant disorder (ODD) in preschool children.
  
  
  METHODS
  Children (n = 54) between the ages of 4 and 6 years from a comprehensive, longitudinal study of preschool emotional development were included in this study. Each child's primary caregiver completed questionnaires and interviews related to childhood psychopathology. SHS exposure was estimated with the use of saliva cotinine values.
  
  
  RESULTS
  After adjustment for sociodemographic factors (e.g., age, gender, an income-to-needs ratio) and for ADHD, CD, and ODD symptoms, exposure to SHS was found to be negatively associated with preschool children's nonverbal reasoning skills. Exposure to SHS continued to be negatively associated with nonverbal reasoning skills after adjustment for maternal education, maternal smoking during pregnancy, and maternal reports of exposure to SHS during pregnancy in separate models.
  
  
  CONCLUSIONS
  Children who grow up in an environment with adults who smoke are vulnerable to several social and environmental risk factors. The findings of this study suggest that exposure to SHS during early childhood should also be considered as a potential variable in the risk trajectory and as a marker of other associated risks when formulating public health intervention and prevention strategies.
authors.affiliation: Department of Psychiatry, Washington University School of Medicine in St. Louis, Missouri, USA.
authors.forename: Duneesha
authors.initials: D
authors.lastname: De Alwis
authors.affiliation: Department of Psychiatry, Washington University School of Medicine in St. Louis, Missouri, USA.
authors.forename: Mini
authors.initials: M
authors.lastname: Tandon
authors.affiliation: Department of Psychiatry, Washington University School of Medicine in St. Louis, Missouri, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Tillman
authors.affiliation: Department of Psychiatry, Washington University School of Medicine in St. Louis, Missouri, USA.
authors.forename: Joan
authors.initials: J
authors.lastname: Luby
keywords: Secondhand smoke; cognition; nicotine; nonverbal reasoning ability; preschoolers