PM-bound PAHs exposure linked with low plasma insulin-like growth factor 1 levels and reduced child height.

BACKGROUND

Exposure to atmospheric fine particle matter (PM) pollution and the absorbed pollutants is known to contribute to numerous adverse health effects in children including to growth.

OBJECTIVE

The aim of this study was to evaluate exposure levels of atmospheric PM-bound polycyclic aromatic hydrocarbons (PAHs) in an electronic waste (e-waste) polluted town, Guiyu, and to investigate the associations between PM-PAH exposure, insulin-like growth factor 1 (IGF-1) levels and child growth.

METHODS

This study recruited 238 preschool children (3-6 years of age), from November to December 2017, of which 125 were from Guiyu (an e-waste area) and 113 were from Haojiang (a reference area). Levels of daily PM and PM-bound ∑16 PAHs were assessed to calculate individual chronic daily intakes (CDIs). IGF-1 and IGF-binding protein 3 (IGFBP-3) concentrations in child plasma were also measured. The associations and further mediation effects between exposure to PM and PM-bound PAHs, child plasma IGF-1 concentration, and child height were explored by multiple linear regression models and mediation effect analysis.

RESULTS

Elevated atmospheric PM-bound ∑16 PAHs and PM levels were observed in Guiyu, and this led to more individual CDIs of the exposed children than the reference (all P < 0.001). The median level of plasma IGF-1 in the exposed group was lower than in the reference group (91.42 ng/mL vs. 103.59 ng/mL, P < 0.01). IGF-1 levels were negatively correlated with CDIs of PM, but not with CDIs of PM-bound ∑16 PAHs after adjustment. An increase of 1 μg/kg of PM intake per day was associated with a 0.012 cm reduction of child height (95% CI: -0.014, -0.009), and similarly, an elevation of 1 ng/kg of PM-bound ∑16 PAHs intake per day was associated with a 0.022 cm decrease of child height (95% CI: -0.029, -0.015), both after adjustment of several potential confounders (age, gender, family cooking oil, picky eater, eating sweet food, eating fruits or vegetables, parental education level and monthly household income). The decreased plasma IGF-1 concentration mediated 15.8% of the whole effect associated with PM exposure and 23.9% of the whole effect associated with PM-bound ∑16 PAHs exposure on child height.

CONCLUSION

Exposure to atmospheric PM-bound ∑16 PAHs and PM is negatively associated with child height, and is linked to reduced IGF-1 levels in plasma. This may suggest a causative negative role of atmospheric PM-bound exposures in child growth.