Gestational phthalate levels and biomarkers of aging in infants and children from New York City.

BACKGROUND

Phthalates, a group of endocrine disrupting chemicals used in plastics, are ubiquitous in the environment and may influence cellular processes related to child health and development. Mitochondrial DNA copy number (mtDNAcn), telomere length (TL), and DNA methylation-based epigenetic gestational age acceleration (EGAA) are accessible biomarkers associated with biological aging and development. Little is known about how gestational phthalate exposure, individually and in mixtures, may impact biomarkers of biological aging through childhood.

METHODS

We used data and samples from the Columbia Children's Center for Environmental Health (CCCEH) Mothers and Newborns Cohort, which recruited women in the third trimester from Northern Manhattan and the South Bronx, New York. Children returned for follow up at ages 5 and 7. We measured phthalate metabolites in third trimester maternal urine, relative mtDNAcn in cord blood (n = 262) or childhood whole blood (n = 340), relative leukocyte TL (rLTL) in cord blood (n = 151) or childhood whole blood (n = 155), and cord blood DNA methylation (n = 188). Phthalates were assessed as metabolites or summed into parent compounds. Associations between phthalate exposure and biomarkers of aging were modeled with generalized linear models. Phthalate mixture effects were assessed using quantile g-computation.

RESULTS

Associations between phthalate metabolites and mtDNAcn and rLTL may reflect altered cellular health but were not robust to multiple comparison correction. At birth, a 10 % increase in monobutyl phthalate was positively associated with mtDNAcn (β = 1.96, 95 % CI: 0.40, 3.52) while a 10 % increase in mono-iso-butyl phthalate was negatively associated with mtDNAcn (β = -1.51, 95 % CI: -2.90, -0.12). A 10 % increase in mono-(3-carboxypropyl) phthalate was associated with a 1.06 percent increase in rLTL at birth (β = 1.06, 95 % CI: 0.17, 1.95). No significant associations were seen with phthalate exposure and EGAA, nor the phthalate mixture.

CONCLUSION

We observed low evidence for the impact of phthalate metabolites on biomarkers of aging.