Changes in persistent organic pollutant levels from adolescence to young adulthood

Area of Science:

• Environmental Chemistry
• Toxicology
• Pharmacokinetics

Background:

• Elimination rates and half-lives are key pharmacokinetic measures for toxicant clearance.
• Conventional regression estimates can be biased by continuous background exposure.
• Persistent Organic Pollutants (POPs) pose health risks, yet their intake vectors and life-course changes require further investigation.

Purpose of the Study:

• To develop and validate an alternative estimator for toxicant elimination rates that corrects for background exposure bias.
• To derive the intrinsic elimination rate, free from ongoing contaminant intake.
• To analyze factors influencing POPs levels and elimination during adolescence to adulthood.

Main Methods:

• Proposed a censored normal regression model, treating non-declining levels as censored observations.
• Utilized sequential POPs measurements from adolescence to adulthood.
• Applied Exploratory Factor Analysis (EFA) to consumption patterns and physical characteristics to identify underlying factors.

Main Results:

• The censored normal regression model provides unbiased estimates of elimination rates, unlike conventional methods.
• Identified seven underlying factors related to diet, behavior, and physiology influencing POPs levels.
• Reported adjusted and unadjusted half-lives for various POPs, including PCBs, p,p'-DDE, and HCB.

Conclusions:

• The censored normal regression model is a superior method for estimating intrinsic elimination rates in the presence of background exposure.
• Understanding life-course changes in POPs requires considering dietary and behavioral factors.
• Accurate toxicant half-life estimation is crucial for risk assessment and public health interventions.