Study Links Secondhand Smoke Exposure to Motor Impairment in Children

CINCINNATI—Secondhand tobacco smoke exposure was significantly associated with motor impairment in a study of children living in the Appalachian region of Ohio and West Virginia, according to new research from the University of Cincinnati (UC).

The study is published online ahead of print in The Journal of Pediatrics, an international peer-reviewed journal that advances pediatric research. The corresponding author is Erin Haynes, DrPH, an associate professor in the UC College of Medicine’s Department of Environmental Health, Division of Epidemiology.

Haynes notes that previous studies have shown evidence of the effects of secondhand smoke exposure on children’s cognition, learning disabilities and behavior disorders, but "to our knowledge, this is the first study examining the relationship between secondhand smoke exposure, using serum cotinine as a biomarker of exposure, and childhood neuromotor function using a comprehensive battery of robust neuromotor tests.”

"These results reinforce the importance of continued interventions to reduce childhood exposure to secondhand smoke,” says Washington County Health Commissioner Richard Wittberg, PhD. "Most parents don’t realize that their tobacco habit is hurting their child’s ability to learn, and—as this study demonstrates—their ability to coordinate movements.”

Environmental tobacco smoke exposure during childhood has previously been associated with deficits in cognition and intelligence, and Appalachian regions—including Eastern Ohio, where the study population is located—have higher tobacco use prevalence than non-Appalachian regions.

The data for the current study was drawn from the Communities Actively Researching Exposure Study (CARES), a community-based participatory research study of 404 children and their families initiated based on community concern about exposure to manganese from a metallurgical manufacturing company near Marietta, Ohio.  A partnership between UC environmental health scientists, Marietta College and the community, CARES has Haynes and Marietta resident Caroline Beidler as co-principal investigators.

The study recruited 404 children ages 7-9 from Marietta and Cambridge, Ohio, and their surrounding communities. Children’s exposure to secondhand smoke was assessed using serum cotinine levels. Cotinine is a metabolite of nicotine and is used as an internal dose marker of exposure to tobacco smoke.

Participants underwent neuromotor tests assessing fine motor and gross motor development and visual motor skills. The associations between serum cotinine and poor neuromotor performance was statistically significant in all tests, says Samrat Yeramaneni, PhD, a postdoctoral fellow at Cincinnati Children’s Hospital Medical Center and the study’s lead author. 

"We found that the children in our study who were exposed to secondhand smoke had poorer fine motor, gross motor and visual-motor skills even after controlling for exposures to lead and manganese,” says Yeramaneni.

The study also examined the effects of manganese on these neuromotor outcomes. Children with both high and low levels of manganese had poorer fine and gross motor function, Haynes says, adding, "Future research is needed to confirm these findings and determine if these neuromotor function deficits continue to persist in adolescence.”

The study was supported by grants from the National Institute of Environmental Health Sciences and an Institutional Clinical and Translational Science Award from the National Institutes of Health’s National Center for Advancing Translational Sciences.