Exposure to Ambient Particulate Matter during Pregnancy: Implications for Infant Telomere Length

BACKGROUND: Growing evidence suggests that air pollution may influence fetal development, with potential consequences for later health. Alteration of telomere length (TL) is one possible mediating mechanism for the link between fetal exposure to air pollution and development of disease. However, the few studies exploring associations between prenatal pollution and infant TL have assessed varied trimesters of pregnancy and shown mixed results. The aim of this study was to examine differential relationships of prenatal exposure to air pollutant PM(2.5) during the 1(st), 2(nd) and 3(rd) trimesters of pregnancy with infant TL at one month of age. METHODS: Women (n=74) were recruited in obstetric clinics during their third trimester. Data on PM(2.5) exposure for each woman’s residential area during each trimester was acquired from the regional Air Quality Management District. At one month postnatal, a salivary sample was collected from the infant which provided DNA for telomere assay. Women completed questionnaires about stressors in their lives, perceived stress, depression, and sociodemographics for inclusion as covariates. Multiple linear regression was used to analyze the aims. RESULTS: PM(2.5) exposure during the 2(nd) (β =.31, p=.003) and 3rd (β =.24, p=.02) trimesters was associated with longer infant TL. Exposure in the 1(st) trimester was not related to TL. Covariates of maternal depression and age, and infant female sex were also associated with longer TL. Variables in the model contributed to 34% of the variance in TL (F=10.58, p=.000). DISCUSSION: Fetal programming of longer telomeres in response to pollution may have adaptive value in preparing the neonate for a postnatal environment that is less than optimal in air quality. Alternatively, longer telomeres may forecast later health risk considering established links between longer TL and diseases such as cancer. Future research needs to address how prenatal pollution interacts with TL to influence health over time.