Associations of Dietary Intake with Urinary Melamine Concentrations among Children aged 4-6 Years in the GAPPS Cohort

Abstract

Describe how children are exposed to the environmental chemical melamine through their diets, and identify potential sources of contamination in children's diets. Melamine is an industrial chemical that may induce kidney injury at low dose exposures and kidney failure at high doses. Diet is a primary source of melamine exposure, yet little is known about exposure levels or dietary sources, particularly among children. Urinary melamine and metabolite concentrations were measured in 123 children aged 4-6 years in the Global Alliance to Prevent Prematurity and Stillbirth cohort. Children’s diets on the day preceding urine collection were assessed through 24-hour recalls. Associations of meat, fruit, and grain intakes with urinary melamine and metabolites were examined in primary analyses using generalized linear modeling. Remaining food groups were examined in secondary analyses. Melamine and ammelide concentrations were above the limit of detection (LOD) in 100% and 88% of samples, respectively. Ammeline concentrations were below the LOD in all samples. Mean urinary melamine and ammelide concentrations were 5.97 ng/mL (SD: 12.08) and 1.80 ng/mL (SD: 2.06), respectively. In minimally adjusted models, a doubling in fatty fish intake was associated with 74% (95% CI: 18%, 130%) greater melamine; this association was diminished in fully adjusted models. In full models, a doubling of yogurt intake was associated with 101% (95% CI: 33%, 167%) greater melamine; doubled dark green vegetable intake was associated with 59% (95% CI: 1%, 117%) lower ammelide. Exposure to melamine and ammelide was pervasive. Possible sources of melamine contamination including yogurt and fatty fish should be confirmed in larger samples. Additional study should clarify how chronic low-level melamine exposure affects children’s health.