Bayesian varying coefficient kernel machine regression to assess neurodevelopmental trajectories associated with...

Area of Science:

• Environmental health
• Developmental toxicology
• Statistical modeling

Background:

• Child neurodevelopment is sensitive to environmental exposures, often involving complex mixtures.
• Existing statistical methods struggle to model simultaneous exposure-response relationships and developmental trajectories.
• Understanding the impact of environmental mixtures on neurodevelopment is crucial for public health.

Purpose of the Study:

• To introduce a novel statistical framework, Bayesian varying coefficient kernel machine regression (BVCKMR), for analyzing environmental mixtures and neurodevelopmental trajectories.
• To flexibly model complex exposure-response relationships, including nonlinear and nonadditive effects.
• To assess the impact of mixture components on health outcome trajectories and predict health effects.

Main Methods:

• Developed the Bayesian varying coefficient kernel machine regression (BVCKMR) hierarchical model.
• Applied BVCKMR to a prospective birth cohort study (PROGRESS) in Mexico City, analyzing metal mixtures (manganese, arsenic, copper, lead, etc.) and neurodevelopment.
• Utilized contour and cross-sectional plots to visualize exposure-response relationships and interactions.

Main Results:

• Significant positive associations were found between second-trimester copper exposure and cognitive scores (Bayley Scales of Infant and Toddler Development) at 24 months.
• Copper exposure also impacted cognitive trajectories from 6 to 24 months.
• An interaction effect between second-trimester copper and lead exposures on 24-month cognition was identified.

Conclusions:

• BVCKMR offers a robust framework for estimating neurodevelopmental trajectories in relation to complex environmental mixture exposures.
• The study highlights the utility of BVCKMR in identifying specific metal exposures and their interactions affecting child cognition.
• This methodology can inform public health strategies aimed at mitigating neurodevelopmental risks from environmental contaminants.