Babies who are exposed to pollution both before they are born and during their first year of life have a higher risk of allergic rhinitis, scientists have suggested.
A study has linked the amount of fine particulate matter that youngsters are exposed to with a risk of allergic rhinitis.
Researchers, led by a team of experts from Taiwan, said the associations between pre- and post-natal exposure to fine particulate matter (PM2.5) and allergic rhinitis were previously not well understood.
So they examined data on 140,000 babies born in Taiwan, whether or not they went on to develop allergic rhinitis.
This was cross-referenced with their levels of exposure to PM2.5 using a combination of methods including satellite time trend readings, meteorological variables, and land use data.
A third of the children – 47,000 – went on to develop allergic rhinitis.
The researchers found a significant association of allergic rhinitis, with rises in PM2.5
from 30 gestational weeks until the babies were a year old.
They said that each 10 µg/m3 increase in PM2.5 was associated with 30% higher odds of an allergic rhinitis diagnosis – the concentration of an air pollutant is measured in micrograms (one-millionth of a gram) per cubic metre of air, or µg/m3.
“Our study provides evidence that both pre-natal and post-natal exposures to PM2.5 are associated with later development of allergic rhinitis,” the authors wrote in the journal Thorax.
“The vulnerable time window may be within late gestation and the first year of life.”
Allergic rhinitis is inflammation of the inside of the nose caused by an allergen, such as pollen, dust, mould or flakes of skin from certain animals.
When pollen is the allergen the condition is known as hay fever.
It is a very common condition, estimated to affect around one in every five people in the UK.
Allergic rhinitis typically causes cold-like symptoms, such as sneezing, itchiness and a blocked or runny nose – which usually start shortly after exposure to an allergen.