Researchers link PM2.5 exposure to infant asthma

NOVEL APPROACH::The researchers used satellite imagery to evaluate PM2.5 exposure in the Taichung region and compared that data with a cohort study

By Su Meng-chuan and Jake Chung  /  Staff reporter, with staff writer

Sat, Jun 15, 2019 - Page 1

Researchers have found that the development of asthma is linked to prenatal and postnatal exposure to airborne particles measuring 2.5 micrometers or less (PM2.5).

The findings were presented in a paper published in the Journal of Allergy and Clinical Immunology coauthored by several researchers, including China Medical University Hospital professor Hwang Bing-fang (黃彬芳), National Taiwan University assistant professor Chen Wei-ting (陳維婷) and Japan Environment and Children’s Study Programme Office professor Jung Chao-ren (鍾朝仁).

The researchers used a cohort study from the Taiwan Maternal and Child Health Database that followed 184,604 children born between 2004 and 2011 in Taichung until 2014.

Previous medical research has concluded that exposure to an environment rich in PM2.5 can trigger an asthma attack or an acute deterioration of the condition, Hwang said.

As more than 300 million people worldwide have asthma — a source of great strain on public health programs and nations’ economies — prevention of the disease has been receiving growing attention and funding in academia, he said.

The researchers said that they used a daily satellite image-based hybrid model to estimate PM2.5 exposure in the Taichung region from 2004 to 2011, citing a collaboration between Harvard University and NASA that found PM2.5 levels could be measured through such imagery.

The cohort study identified 34,336 children with asthma, who were diagnosed with the disease at a mean age of 1.78 to 3.39 years old, Hwang said.

Children exposed to higher levels of PM2.5 during gestational weeks six to 22 and nine to 46 weeks after birth had a significant association with an increased incidence of asthma, he said.

“The exposure-response relationship indicated that the hazard ratio of asthma increased steeply at PM2.5 exposure of greater than 93 micrograms per cubic meter during pregnancy,” paper’s abstract says.

Postnatal exposure to PM2.5 concentrations of 26 to 72 micrograms per cubic meter are also significant, the researchers said, adding that exposure to PM2.5 concentrations of more than 73 micrograms per cubic meter caused a sharp spike in the hazard ratio of asthma.

They concluded that vulnerable periods could include the periods of early gestation, mid-gestation and infancy.

Pregnant women and infants should avoid going outside during peak PM2.5 density periods to reduce the risk of children developing asthma, Hwang said.