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Your Environment. Your Health.

Identifying Sensitive Windows of Prenatal Exposure to Air Pollution

Robert O. Wright, M.D., Ph.D.
Icahn School of Medicine at Mount Sinai
R01ES013744, R01ES014930, R01ES021357, P30ES023515, R00ES023450

NIEHS grantees found that increased prenatal exposure to particulate matter less than 2.5 micrometers (PM2.5) during a specific portion of the third trimester may increase oxidative stress and susceptibility to health effects mediated by white blood cells, such as infections and immune response to allergens. During this window in late pregnancy, increased exposure to PM2.5 air pollution was associated with lower mitochondrial DNA content in cord blood, a marker of oxidative stress. Oxidative stress is an imbalance in the production of free radicals and the body’s ability to counteract their harmful effects.

The study involved participants in the NIH-funded Programming Research in Obesity, Growth, Environment, and Social Stressors cohort in Mexico City The researchers measured the mitochondrial DNA content of white blood cells in umbilical cord blood collected from mothers at delivery. They also estimated daily exposure to PM2.5 during pregnancy using a satellite method that estimates particulate levels across Mexico City.

The researchers compared the exposure levels during pregnancy to the mitochondrial DNA content in white blood cells at birth. They found that babies were more sensitive to mitochondrial DNA changes when they had higher exposures to PM2.5 during gestation weeks 35 to 40. They also found that PM2.5 was more strongly associated with differences in mitochondrial DNA content in boys compared with girls.

Citation: Rosa MJ, Just AC, Guerra MS, Kloog I, Hsu HL, Brennan KJ, Garcia AM, Coull B, Wright RJ, Tellez Rojo MM, Baccarelli AA, Wright RO. 2017. Identifying sensitive windows for prenatal particulate air pollution exposure and mitochondrial DNA content in cord blood. Environ Int 98:198–203.