New Leads stands for "New Leukemia and Down Syndrome" Study. This study is actually made up of two separate studies. One is designed to learn more about what causes leukemia in children with Down syndrome. The other is designed to learn more about what causes Down syndrome. Dr. Julie A. Ross and her staff at the University of Minnesota conducted the study. Children with leukemia and Down syndrome were identified through the Children's Oncology Group. The Children's Oncology Group consists of over 200 hospitals in North America that treat nearly all children with cancer.

Between 1998 and 2002, the following parents took part in the study:

• Mothers and fathers of 158 children with Down syndrome and leukemia
• Mothers and fathers of 173 children with Down syndrome
• Mothers and fathers of 176 children without Down syndrome or leukemia

On this page:

• Why were these studies done?
• What is leukemia?
• What has been learned so far?
• What do these results mean?
• References
• Contact Us

Why were these studies done?

Children with Down syndrome are more likely to develop leukemia than other children. In the first study, the children with Down syndrome and leukemia and the children with Down syndrome but not leukemia are being compared. The researchers want to see what, if anything, is different about those who have leukemia. Things that are different between the two groups of children may be clues about why some children with Down syndrome develop leukemia and others do not. This is the first study to look at why some children with Down syndrome develop leukemia.

In the second study, the children with Down syndrome and the children without Down syndrome or leukemia are being compared. The researchers are looking for differences between those with Down syndrome and those without Down syndrome. The differences they find may be clues about what causes Down syndrome.

These studies are called epidemiologic studies. In these studies, researchers gather information from many families. The researchers compare the experiences and characteristics of children with a disease to those of children without the disease. They look for things that are more common in children with the disease. In the studies, mothers and fathers answered questions about many things in a one-hour telephone interview. The questions were about the child's medical history, family health history, personal habits such as smoking, history of pregnancies, and events surrounding the child's birth. We did not know whether any of these things make leukemia or Down syndrome more likely. We asked in order to try to find out. Only by asking these questions can we learn whether any of these things make leukemia or Down syndrome more likely. We do not expect this study to find the cause of leukemia or Down syndrome. We do expect that it will give us clues.

What is leukemia?

Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place. Sometimes this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. This is cancer. Leukemia is cancer that begins in blood cells. At first, leukemia cells function almost normally. In time, they may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for the blood to do its work. For more information, visit the National Cancer Institute's "What You Need to Know About Leukemia" Web page.

What has been learned so far?

We looked at infections early in life in children with Down syndrome and leukemia and children with only Down syndrome. Our results showed that children with Down syndrome who get infections early in life may be less likely to develop leukemia. This finding was published in a medical journal (see reference 1 below). We also have found that taking vitamins early in pregnancy may make acute lymphoblastic leukemia (ALL) less likely to develop. However, taking vitamins did not seem to make acute myeloid leukemia (AML) less likely (reference 2). We also learned that being exposed to pesticides may make ALL more likely to develop. However, we did not have enough interview information to look at the relationship with specific chemicals (reference 3). Finally, we did not find evidence that a parent's or child's exposure to x-rays (such as x-rays, fluoroscopies, and CT scans) makes it more likely that a child with Down syndrome will develop leukemia (reference 4). We are still looking at the information we gathered from the families. We are learning more as we further study the information.

What do these results mean?

When you think about how the results of these studies relate to you and your families, it is important to know that, despite their careful design, these are observational studies. The results do not prove the causes of leukemia or Down syndrome. Like other such studies, these studies may have some pitfalls that are not yet known. Therefore, the results need to be confirmed through other studies before we can draw any firm conclusions about the causes of leukemia among children with Down syndrome or Down syndrome. For example, it is possible that something may seem more common in children with leukemia than in other children and yet it may not be a cause of leukemia. This could happen just by chance. Or, it could happen because the parents of children with leukemia are likely to think very carefully about the events that occurred prior to pregnancy, during the pregnancy, and after the child's birth. They may think about these events more than other parents since they naturally want to understand why the leukemia developed. Parents of children with leukemia may remember minor events that other parents often forget. In designing our study of leukemia, we were predicting that parents of children with Down syndrome but not leukemia would be about as likely to remember events as parents of children with Down syndrome and leukemia. (But, we cannot prove that this is true, in general.)

It is also important to keep in mind that these results are for average risk of groups, not for specific individuals. Specific individuals may have other characteristics or experiences important in the development of leukemia or Down syndrome. For example, if a study finds a 10% increased risk of a condition in a population due to exposure to a certain factor, this means that, on average, people who are exposed to this factor are 10% more likely to develop the condition compared to people who are not exposed. However, some people will be more likely than average (and some will be less likely) to develop the condition from the exposure because of other differences (such as genetic differences or other exposures).

References

References:

Canfield K, Spector LG, Robison LL, Roesler M, Olshan AF, Smith FO, Heerema N, Barnard D, Blair CK, Lazovitch D, Ross JA. Childhood and maternal infections and risk of acute leukemia in children with Down syndrome: a report from the Children's Oncology Group. Br J Cancer 2004; 91:1866-1872.

Ross JA, Blair CK, Robison LL, Smith FO, Olshan AF, Heerema N, Roesler M. Maternal vitamin supplementation and risk of leukemia in children with Down syndrome. Cancer 2005; 104:405-410.

Alderton LE, Spector LG, Blair CK, Roesler M, Olshan AF, Robison LL, Ross JA. Child and maternal household chemical exposure and the risk of acute leukemia in children with Down syndrome: a report from the Children's Oncology Group. In press, Am J Epidemiol.

Linabery AM, Blair CK, Olshan AF, Gamis AS, Smith FO, Ross JA. Exposure to medical test irradiation and acute leukemia among children with Down syndrome: a report from the Children's Oncology Group. In press, Pediatrics.

Sponsor: National Institutes of Health/National Cancer Institute (R01 CA75169)

Contact Us

Researcher in charge of the study:
Julie A. Ross, Ph.D.
University of Minnesota Cancer Center
MMC 422
420 Delaware St. SE
Minneapolis, MN 55455

Questions?
Please call the study staff at the University of Minnesota, toll-free, at 1-800-511-2629 or e-mail us at pedsepi@tc.umn.edu.