A bacterium strain known as Helicobacter pylori may raise the risk of childhood leukaemia, according to a new study.
Two-thirds of the world population carries H. pylori, which is responsible for ulcers.
Leukaemia accounts for 25 percent of all childhood cancers worldwide. Acute lymphoblastic leukaemia (ALL) makes up 80 percent of all childhood leukaemia.
Clusters of ALL often occur in families, prompting researchers to suspect that there may be a tie between some microbial infection and leukaemia.
Dr. Mati Lehtinen from the National Public Health Institute in Oulu, Inland and fellow colleagues studied H. Pylori along with two other pathogens, namely Mycoplasma pneumonia and Chlamydia pneumonia, to see any of these bacteria had any association with childhood leukaemia.
The cohort study involved 550,000 mothers and their children who resided in Finland or Iceland.
The researchers found that in the group from Iceland, children born to the mothers who tested positive for H. pylori were 2.8 times more likely to contract leukemia.
The risk was 3.7 times higher when the analysis was performed only on Icelandic cases diagnosed before the age of six.
In the group from Finland, H. pylori infection was not associated with an increased risk of childhood leukemia, according to the study.
However, there was no link between the leukemia risk and other two bacteria found.
Caution is needed to interpret the results. The results did not indicate that carriers of H. pylori would have a high risk of leukemia in their children. The association may or may not be coincidental.
(American Journal of Epidemiology)