Prenatal Exposure to Phthalate Metabolites Associated with Shorter Telomere Length in Newborns

by | Apr 22, 2020 | 2019, Environmental Health, Infant and Children's Health

Written by Angeline A. De Leon, Staff Writer. First trimester urinary concentrations of six phthalate metabolites were inversely associated with the telomere length of newborn umbilical cord blood.

women's health - pregnancyTelomeres are regions of noncoding nucleotide sequences at the end of each DNA strand which serve to protect genomic information 1. Telomere length (TL) shortens over the course of biological aging 2 and has been shown to be affected by oxidative insult such as inflammatory processes and oxidative stress 3. Shorter TL is associated with a number of age-related diseases, including cancer, type 2 diabetes, and all-cause mortality 4,5. TL in early life is even thought to reflect individual longevity and disease risk 6, with TL at birth representing initial TL setting 7. Looking at the factors involved in influencing newborn TL is, therefore, of great research interest, and several studies have already identified key determinants, including maternal psychosocial stress 8, maternal smoking 9, and maternal heavy metal exposure 10. One cross-sectional study revealed a significant positive association between urinary phthalates and TL in adults 11, however, the relationship between prenatal phthalate exposure and newborn TL is still lacking. To this end, a study 12 published in Environmental Health Perspectives (2019) explored the link between prenatal phthalate exposure and umbilical cord blood TL.

A total of 762 mother-newborn pairs were enrolled in a prospective birth cohort study (mean age of mothers = 28.6 years). Umbilical cord blood was drawn immediately at the time of delivery, and TL was measured from samples using quantitative real-time polymerase chain reaction. Urine samples were collected from pregnant women at 13, 23.6, and 36 weeks of gestation (about once during each trimester) and analyzed for six phthalate metabolites [mono-ethyl phthalate (MEP), mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono(2-ethyl-5-oxohexyl) phthalate, (MEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-butyl phthalate (MBP), mono(2-ethylhexyl) phthalate (MEHP), and the total concentration of di(2-ethylhexyl) phthalate (ΣDEHP)]. Statistical analysis was then used to explore associations between prenatal urinary phthalate concentrations and newborn umbilical cord blood TL.

Multivariate analyses showed that for each doubling of maternal urinary MECPP, MEHHP, MEOHP, and ΣDEHP during the first trimester, cord blood TL was shorter by 2.38% (95% Confidence Interval: -4.22% to –0.51%), 2.53% (95% CI: -4.38% to –0.64%), 2.90% (95% CI: -4.76% to -1.01%), and 3.25% (95% CI: -5.26% to –1.20%), respectively. Maternal urinary MEP during the first trimester was inversely associated with cord blood TL only in females (percent change = -3.07%, 95% CI: -5.20% to –0.89%) (Psex-int = 0.03). Inverse associations between maternal urinary MECPP, MEOHP, MEHHP, and ΣDEHP during the first trimester and cord blood TL were consistent between both males and females (all Psex-int > 0.10).

The current investigation provides preliminary evidence to suggest that maternal exposure to phthalate metabolites, namely MECPP, MEHHP, MEOHP, and ΣDEHP, during the first trimester is linked to shorter cord blood TL in newborns. Findings indicate that newborn TL is affected by intrauterine stressors such as phthalate exposure, confirming how critical the prenatal period is in the programming of subsequent health outcomes. Further research is needed to elucidate the potential mechanisms involved in the relationship between phthalate exposure and telomere dynamics, as well as the sex-specific effects of certain phthalate metabolites, as seen in the current study. Main limitations of the study include failure to account for individual differences in metabolism, which may have influenced measured urinary phthalate concentrations, the collection of urine samples only once per trimester, which may not accurately reflect exposure profiles, and the limited range of phthalate metabolites which were selected for testing.

Source: Song, Lulu, Bingqing Liu, Mingyang Wu, Lina Zhang, Lulin Wang, Bin Zhang, Chao Xiong et al. “Prenatal Exposure to Phthalates and Newborn Telomere Length: A Birth Cohort Study in Wuhan, China.” Environmental health perspectives 127, no. 8 (2019): 087007.

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Posted April 22, 2020.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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