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Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

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1. In this prospective analysis, prenatal exposure to environmental pollution was associated with decreased telomere length in newborns.

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2. The link between prenatal pollution and telomere length demonstrated a non-linear dose-response relationship, and displayed the greatest effect in the second trimester.

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Evidence Rating Level: 2 (Good)

Study Rundown:

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Telomeres are short stretches of DNA are the ends of chromosomes and are essential for fidelity of genetic information during cell division. Telomere length (TL) has been associated with cellular longevity and is thought to play an important role in cellular aging and senescence. Many exposures, including pollution, may have an effect on TL. The role of prenatal environmental pollution exposure on neonatal telomere length and its predisposition to cellular aging is unknown. The current study found that prenatal environmental pollution exposure was linked to decreased telomere length measured in cord blood and placental cells. The second trimester in particular was demonstrated to be a vulnerable time during gestation.

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The study provides evidence about the role of prenatal exposures on TL. Further investigations are needed to understand how pollution directly or indirectly influences telomere integrity, and how TL at birth may influence lifelong clinical outcomes. However, this does provide evidence that minimizing environmental pollution exposure in utero may positively influence TL and cellular resilience. The major limitations of the study include the reliance on estimates of pollution that may not reflect actual prenatal exposure, lack of data on parental TL, and the evaluation of TL at a single time point rather than with dynamic measurements.

In-Depth [prospective cohort]:

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This study was a prospective cohort study from Flanders, Belgium as part of the Environmental Influence on Ageing in Early Life (ENVIRONAGE) study. Mother-child pairs were included if they were singleton full-term births, from 2010-2014 and had TL assays performed, and could fill out questionnaires in Dutch. TL measurement was obtained using DNA from cord blood and placental cells and evaluated with quantitative PCR. Pollution exposure was estimated with high resolution spatial temporal interpolation method from daily mean particulate matter (PM)25 measurements obtained from fixed-site monitoring and satellite estimates.

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An increase of 5 μg/m3 increment in PM2.5 exposure was associated with 8.8% (95%CI, −14.1%to −3.1%) and 13.2% (95%CI, −19.3%to −6.7%) decreased telomere length in cord blood and placental cells respectively. In sensitivity analysis, the second trimester was determined to be the most vulnerable time for pollution effect on TL.

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