(RxWiki News) Recently, diesel fumes were classified as cancer-causing agents. High exposure to diesel fumes is a risk factor for lung cancer. Now, traffic exhaust is being associated with childhood cancers.
Exposure to high levels of traffic-related air pollution during pregnancy may increase the likelihood of three childhood cancers.
These findings, presented at the American Association for Cancer Research (AACR) Annual Meeting 2013, are adding to an understanding of childhood cancer risk factors.
"Avoid high-traffic areas while pregnant."
Julia Heck, PhD, MPH, assistant researcher in the Department of Epidemiology at the University of California, Los Angeles School of Public Health, led the study.
“We studied pregnancy exposures because the fetus is likely to be more vulnerable to environmental factors during that time, and we also know that certain childhood cancers originate in utero,” Dr. Heck said in a news release.
Researchers identified 3,590 children under the age of 5 who were diagnosed with cancer. These kids were compared with 80,224 children who did not have cancer.
Using sophisticated technology called the California Line Source Dispersion Modeling Version 4 (CALINE4), investigators estimated local traffic air pollution at the mother's residence during each trimester of her pregnancy and during the first year of the child’s life.
Pollution data was based on gasoline and diesel emissions, traffic volume and roadway geometry within about 5,000 feet around the mother's home.
Every measured increase in traffic-related air pollution exposure was associated with a 4 percent increased risk of developing acute lymphoblastic leukemia (blood cancer), a 19 percent increased risk of all types of retinoblastoma (cancer of the eye) and a 17 percent increased risk of germ cell tumors (testicle and ovary).
It should be understood that childhood cancers are very rare. The most common childhood cancer is acute lymphoblastic leukemia, which affects just under 3,000 children a year. About 900 children develop germ cell tumors and some 250 youngsters are diagnosed with retinoblastoma in the US every year.
“This is the first study that’s ever been reported on air pollution as it relates to rarer pediatric cancers, so it needs to be replicated in other states or in other countries,” Dr. Heck said. “It would be interesting to determine if there are specific pollutants like benzene or polycyclic aromatic hydrocarbons that are driving these associations.”
All research is considered preliminary before it’s published in a peer-reviewed journal.