It is already known that multivitamins containing folic acid should be taken in the early stages of pregnancy to reduce the risk of development of a neural tube defect like spina bifida in the fetus.
"This current study suggests another possible protective effect for the vitamins," said study leader Greta R. Bunin, Ph.D., of The Children's Hospital of Philadelphia. She added, "Children whose mothers took multivitamins close to the time of conception seemed less likely to suffer medulloblastoma and primitive neuroectodermal tumors of the brain."
Medulloblastoma is the second most common brain tumor in kids. However, childhood brain tumors are rare. Medulloblastoma occurs in one in 20,000 children under age 6, it develops in the cerebellum, the lower portion of the brain, and the area of the brain that coordinates movement.
A different part of the central nervous system is affected by Primitive neuroectodermal tumors of the brain (PNET), which are similar to medulloblastoma.
Dr.Bunin and her team conducted a comparative study on 315 children diagnosed with those tumors before age six and equal number of their normal counterparts. The Children's Oncology Group, a multicenter collaborative organization of pediatric cancer programs in the U.S. and Canada had enrolled the kids with cancer chosen for this study. These kids were diagnosed between 1991 and 1997. A telephone survey was conducted in which the mothers were interrogated.
"Children whose mothers took multivitamins close to the time of conception seemed less likely to suffer medulloblastoma and primitive neuroectodermal tumours of the brain," said Dr. Bunin.
The study was published in the September issue of Cancer Epidemiology Biomarkers & Prevention.
The results were similar to a previous study conducted by the same team in 1993. Hence, they conclude that the obvious advantages could not have occurred by chance.
However, the study revealed that taking multivitamins later in pregnancy did not much reduce the child's risk of medulloblastoma and PNET.
"Our findings suggest that the time close to conception may be a critical period in the development of these tumors," said Dr. Bunin.
"However, most women do not yet know they are pregnant at this very early stage. That is why women of reproductive age are advised to take multivitamins to prevent neural tube defects even if they are not trying to get pregnant."
The mothers' interrogation included the frequency of consumption of cured meats that have compounds shown to cause nervous system tumors in animals. No rise in risk of tumor was found in kids of mothers who often consumed those meats during pregnancy.
"Taking multivitamins in the first few weeks of pregnancy definitely helps prevent neural tube defects," concluded Dr. Bunin. "While more research remains to be done, our findings suggest that multivitamins may prevent some brain tumors as well."
This research was supported by the National Cancer Institute, part of the National Institutes of Health. Paul R. Gallagher, Lucy B. Rorke-Adams, M.D., and Avital Cnaan, Ph.D., all of The Children's Hospital of Philadelphia, with Leslie R. Robison, Ph.D., of St. Jude Children's Research Hospital, Memphis, Tenn. Drs. Bunin and Cnaan and faculty members of the University of Pennsylvania School of Medicine were Dr. Bunin's co-authors.