Association between prenatal exposure to household inhalants exposure and ADHD-like behaviors at around 3 years of age: Findings from Shenzhen Longhua Child Cohort Study

Background: Prenatal exposure to air pollutants has been suggested as a possible etiologic factor for the occurrence of ADHD or ADHD-like behaviors. But we still lack a comprehensive assessment of household air pollutants exposure on the development of ADHD-like behaviors during childhood.

Object: We aimed to assess whether prenatal household inhalants exposure is associated with preschoolers' ADHD-like behaviors in a nonclinical population.

Methods: This study used the baseline data of the Longhua Child Cohort Study. During 2015-2017, we recruited 42,983 mothers and their kindergarten-aged children who enrolled at kindergarten in the Longhua district of Shenzhen, to obtain the demographic data and relevant exposure information through self-administrated questionnaire survey. The source of prenatal household inhalants exposure include cooking fumes, environmental tobacco smoke, mosqutio coils, home renovated and indoor burning incense. Logistic and censored least absolute deviations (CLAD) models were used to reveal the association between prenatal exposure to household air pollutants and hyperactive behaviors in child.

Results: We found that exposure to five types of household inhalants during pregnancy were independently associated with an increased risk of child hyperactive behaviors. Moreover, we observed a significant interaction between exposure to environmental tobacco smoke and cooking fumes during gestation on child hyperactive behaviors in CLAD models. We also found a significant joint effect between burning mosquito coils and incense during gestation for child hyperactive behaviors risk both in CLAD and Logistic models. Furthermore, a household inhalants exposure index was used to demonstrate a dose-response relationship between the cumulative effect of exposure to the five household air pollutants and child hyperactivity.

Conclusions: Our results suggest that prenatal exposure to different household inhalants might increase the risk of children's hyperactive behaviors at around 3 years of age with the presence of interaction effects between some inhalants.