26 June 2007
Smog And Women - A Bad Combination
by Kate Melville
Intriguing research from Penn State University shows that air pollution has a bigger effect on the immune system of females than males - at least in mice. The experiments showed that ozone - a major component in air pollution - markedly reduced the females' ability to fight off pneumonia.
Ozone is a major pollutant in American cities and more than 100 million people in the US live in areas with ozone levels higher than recommended by the EPA's air quality standards. Ozone is the primary ingredient of smog at ground level and is known to exacerbate respiratory problems.
Differences in immune function between males and females have been noted in the past, but this study is the first to suggest that air pollutants have a significantly higher negative effect on females than on males.
The researchers behind the new study, presenting their findings at the recent Experimental Biology Meeting, suggest that consideration of the role of environmental pollutants on health should also take gender into account.
The study showed that the mice exposed to ozone before infection with pneumonia died more often than did mice that had breathed only filtered air. Additionally, ozone was even more damaging to one type of mouse, which was genetically engineered without the gene responsible for producing a host defense protein called SP-A. SP-A is a molecule that provides first-line defense in the lung against various inhaled irritants, bacteria, viruses, and pollen.
But it was the marked difference in gender survival rates that most surprised the researchers. Ozone exposure significantly decreased the likelihood of surviving pneumonia exposure for the female mice compared to males, regardless of whether they were wild-type or genetically altered mice.
"If we could extrapolate what we found to the human population, it would mean women with lung infections may be at higher risk for negative outcomes if they are exposed to high amounts of air pollution, and in particular, ozone," concluded Penn State's Joanna Floros.
Source: Penn State College of Medicine