For some cancers, risk lower among kids of non-US-born Hispanic mothers

A phenomenon known as the "Hispanic epidemiologic paradox" suggests that non-U.S.-born Hispanic mothers who immigrate to the United States have better pregnancy outcomes than their U.S.-born counterparts, such as decreased rates of low birth weight. Whether that advantage extends to childhood cancer risk is unknown. It is important to study childhood cancer risk in this large and growing population.

Julia E. Heck, Ph.D., of the University of California, Los Angeles, and coauthors used California birth records to identify children born from 1983 through 2011. Information on cancer cases came from California Cancer Registry records from 1988 to 2012.

The authors restricted their analysis to children of U.S.-born white, U.S.-born Hispanic or non-U.S.-born Hispanic mothers. The study included 13,666 cases of children diagnosed with cancer before the age of 6 years and more than 15.5 million children without a diagnosis of cancer before the age of 6 years who served as control participants for comparison.

The study reports that compared with children of non-Hispanic white mothers, the children of non-U.S.-born Hispanic mothers had reduced risks for cancers such as glioma (brain), astrocytoma (brain), neuroblastoma (a type of solid tumor) and Wilms tumor (kidney).

Risk estimates for these cancer types for children of U.S-born Hispanic mothers were between those for children of U.S.-born white mothers and non-U.S.-born Hispanic mothers. Hispanic children, regardless of where their mothers were born, had higher risks for acute lymphoblastic leukemia and Hodgkin lymphoma, according to the study.

Why Hispanic children may have differing cancer rates compared with white children may include genetic variation, infection exposures early in life, lifestyle differences and varying environmental exposures, according to the study.

"Incorporating the immigrant experience into studies of childhood cancer may help to inform research on disease etiology, identify vulnerable populations and highlight opportunities for cancer prevention. Further studies should explore the differences in risk incurred by variation in environmental, behavioral and infectious exposures between non-U.S. -- and U.S.-born Hispanic mothers," the authors conclude.