SYDNEY, AUSTRALIA. Leukemia is the most common cancer among children in developed countries. The causes of childhood leukemia are largely unknown, but there is some indication that environmental factors and exposure to radiation could play a role. Researchers at the Cancer Foundation of Western Australia now report the results of a comprehensive study aimed at determining the risk factors for acute lymphoblastic leukemia. The researchers compared 83 children under the age of 14 years with leukemia with 166 healthy children matched for sex, date of birth, and broad region of residence. They interviewed both the mother and father of each child and also determined the child's exposure to various expected risk factors. As an add-on they also asked the mothers about their use of medicines and supplements during pregnancy.
Not unexpectedly, they found that children who had been exposed to pesticides and x-rays had a three-fold increased risk of leukemia. A mother's exposure to agricultural chemicals, glues or resins during pregnancy increased the risk by a factor of three or four. A father's exposure to paints or pigments (at work) or to solvents, degreasers or cleansing agents or other industrial chemicals, in the five-year period prior to the child's birth, was associated with a three-fold risk increase. Completely unexpected was the finding that children born to women who had supplemented with iron and folic acid during pregnancy had a three times (0.37 odds ratio) lower risk of developing leukemia than did children born to mothers who had not supplemented.
The researchers believe that the folic acid is responsible for the protective effect, but could not separate the
effects of iron and folic acid as they were always taken together. They point out though that folic acid has
been associated with a reduced risk of colon cancer. The researchers conclude that folic acid
supplementation during pregnancy reduces the risk of childhood leukemia. NOTE: The RDA for iron and
folic acid during pregnancy is 30 mg/day and 400 micrograms/day respectively.