Heavily polluted areas, such as the South Coast Air Basin of California, have higher rates of infant death from respiratory problems and sudden infant death syndrome (SIDS), researchers from the University of California in Los Angeles say.

Researchers examined birth and death certificates for Southern California infants who died between 1989 and 2000. They compared each infant who died with 10 living children born around the same date. Using air quality monitoring records provided by the state of California and zip code information, researchers determined each child's exposure to outdoor pollutants (specifically carbon monoxide, nitrogen dioxide, ozone, and particulate matter) in the 2 weeks, 1 month, 2 months, and 6 months prior to death.

Infants who resided in this area of California who were exposed to high levels of both gases (carbon monoxide and nitrogen dioxide) and particulate matter had an increased risk of death during the first year of life. As pollution levels increased, so did the risk of death among infants, and both short- and long-term exposure to air pollution increased the risk.

Most of the children who lived in the heavily polluted areas died from respiratory problems or SIDS. Researchers also found that low birth weight and premature babies tended to be especially susceptible to death if they were exposed to higher levels of air pollution. The study did not investigate the role that other variables may contribute to respiratory diseases and SIDS in infants, such as infant sleeping position or exposure to tobacco smoke.

What This Means to You. Babies' airways are especially sensitive to poor air quality, and both short- and long-term exposure to outdoor pollution increases the risk that babies will develop respiratory diseases or die of SIDS. You may not be able to change the air quality where you live, but you can reduce the risk of respiratory illness, infection, asthma, and SIDS by eliminating your child's exposure to tobacco smoke. Avoid smoking around your baby and don't allow anyone to smoke in your home, either. You can also reduce the risk of SIDS by always placing your child on his or her back to sleep.

Source: Beate Ritz, MD, PhD; Michelle Wilhelm, PhD; Yingxu Zhao, PhD; Pediatrics, August 2006.

Reviewed by: Steven Dowshen, MD
Date reviewed: August 2006