Pregnant women who are exposed to elevated levels of air pollution give birth to babies with increased signs of “aging” within their body cells, according to a new study published in JAMA Pediatrics.
To put that another way, babies that are exposed to higher levels of air pollution when in the womb during gestation (via their mother) possess shorter caps on the ends of their chromosomes — which means that there’s now a new mechanism to explain some of the health problems present in children who live in areas with high levels of air pollution.
To explain that a bit further here, telomeres can be described as “protective caps” present on chromosomes, not too inaccurately anyways; as people age and are exposed to stressors of various kinds, they shrink.
Reuters provides more: “For the study, Tim Nawrot of Hasselt University in Diepenbeek, Belgium, and colleagues examined telomere length from samples of cord blood and placental tissue for 641 newborns in the Flanders region. They also looked at mothers’ exposure to pollutants known as PM 2.5, a mixture of solid particles and liquid droplets smaller than 2.5 micrometers in diameter that can include dust, dirt, soot, and smoke and are often found in traffic exhaust.
“Some previous research has linked exposure to traffic fumes and air pollution to higher odds of infertility as well as an increased risk of delivering underweight or premature babies. Prior research has also linked shorter telomeres to an increased risk of a variety of chronic health problems in adults, including heart disease and cancer. Telomeres shorten each time a cell divides. Once telomeres are too short, cell growth stops, which is why their length is considered a potential indicator of cellular aging and overall health.
“In the current study, Nawrot’s team examined data on women who had full-term babies from 2010 to 2014. Researchers used mothers’ home addresses to estimate average exposure to PM 2.5 during each week of pregnancy. Overall, the women’s average weekly exposure to PM 2.5 was 13.4 micrograms per cubic meter of air (ug/m3).”
What this line of enquirer discovered is this: The higher the pregnant woman’s level of exposure to PM 2.5, the shorter the telomeres in their babies when they’re born.
Continuing: “Each increase of 5 ug/m3 in PM 2.5 exposure during pregnancy was associated with roughly 9% shorter telomeres in babies’ cord blood on average, and 13% shorter telomeres in placenta samples, the study found. The researchers accounted for other maternal factors like education, income, health conditions and smoking history, as well as the babies’ sex and weight at birth.”
It should be noted here that exposure to PM 2.5 wasn’t measured directly but was simply inferred from the residential addresses of the pregnant women in question — so there are some limitations to the study. The study authors themselves note that it’s “also possible that the babies’ parents had shorter telomeres and this influenced the telomere length in newborns,” as summarized by Reuters.
Regardless, the new study adds compellingly to the growing body of evidence linking exposure to “normal” levels of air pollution to a wide host of health problems. In particular, the new study adds to evidence suggesting that common forms of air pollution can cross the placenta barrier and directly impact developing fetuses.