Traffic May be Deadly, But Not the Way You’d Expect

Air pollution from traffic linked to childhood leukemia

(RxWiki News) Many people consider living near traffic to be dangerous for children, fearing accidents. New research suggests that traffic can be harmful to children for other reasons.

This new research found that there may be a link between childhood cancer and residential traffic exposure.

The findings showed that children raised in areas of heavy traffic were more likely to develop leukemia than children raised far away from traffic.

The researchers suggested that public health measures to reduce this cancer risk may be a useful intervention.

"Consider making traffic a factor when deciding where to raise children."

This meta-analysis was led by Vickie Boothe, MPH, from the Office of Public Heath Scientific Services in Atlanta, Georgia.

Boothe and colleagues looked at studies published between January 1980 and July 2011 that they found through a systematic search of 18 databases. They noted that a motivation for conducting this study was that childhood cancer has increased in the United States since 1975.

Eleven studies met their inclusion criteria with childhood cancers as the outcome. Seven of the studies found there was an association between postnatal (after birth) exposure to traffic pollution and childhood leukemia, and four studies found there was no association between exposure to traffic pollution prenatally (while the mother is pregnant and the child not yet born) and childhood leukemia.

Children raised in heavily trafficked areas were about 50 per cent more likely to have leukemia than children raised in areas where traffic was minimal.

There were more than 8,000 children 14 years and under included in the studies.

The studies varied in that some looked at multiple-road measures, including how dense traffic was in a 1,500-foot buffer zone, and other studies used single-road measures such as the distance from the home to the nearest major road or density of traffic on the street of residence. The studies also assessed traffic exposure at various time points and periods.

Boothe and team noted that recent studies support their findings, and there has been much speculation that “traffic emissions represent a primary source of known carcinogens, including benzene. Recent mechanistic studies suggest that benzene exposures can initiate both ALL (acute lymphoblastic leukemia) and AML (acute myeoblastic leukemia)."

These researchers noted that their analysis was limited by a small number of studies, that exposure to traffic pollutants is difficult to measure, and that their meta-analysis lumped all childhood leukemias together. They cautioned that further research is necessary.

The authors also noted that more than 10 percent of the US population resides near major roads, and this percentage jumps to 30 to 45 percent in some large urban neighborhoods.

Given recent findings that there seems to be an association between traffic and childhood leukemia, the authors noted that public health measures might be taken, such as minimizing the construction of housing close to major traffic areas, or warning parents of a potential link. They also suggested that parents may wish to take the findings into consideration when contemplating a place to live and raise their children.

This study appeared in the April issue of the American Journal of Preventive Medicine.

No conflicts of interest were disclosed.

Review Date: 
March 26, 2014