Associations between household incense burning and delayed motor development among preterm infants modified by gestational age and maternal educational status.

Background: Household incense burning is a common ritual behavior in the Asia-Pacific region but has been associated with inferior developmental outcomes in term infants. We aimed to examine these associations among preterm infants.

Methods: Information from 1190 mother-infant pairs during 6- and 18-month follow-up to the Taiwan Birth Cohort Study was examined for associations between household incense burning exposure and infant neurodevelopmental milestone achievement using multivariable Cox proportional hazard model with propensity score weighting, along with stratified, sensitivity, and decomposition analysis.

Results: Household incense burning exposure was associated with delayed gross motor milestone achievement among all preterm infants according to the Cox model and after propensity score weighting. Meanwhile, associations for delayed development were found in gross motor domain milestones among late preterm infants, while fine motor domain delay was found among other preterm infants. Furthermore, the associations between household incense burning status and gross motor milestone delays were attenuated by the interaction between higher education level and household incense burning exposure status.

Conclusions: Household incense burning exposure was associated with delays, and the motor domains affected differed according to degree of prematurity. These associations were modified by the attenuation upon higher maternal educational status and exposure status interaction.