Related Experiment Video
Updated: Apr 30, 2026
Modeling Chemotherapy Resistant Leukemia In Vitro
Published on: February 9, 2016
Exposure to infections and risk of leukemia in young children
Erin L Marcotte1, Beate Ritz2, Myles Cockburn3
1Authors' Affiliations: Department of Pediatrics, Division of Epidemiology and Clinical Research, University of Minnesota, Minneapolis, Minnesota; Departments of.
Insights
Early childhood infections may protect against pediatric acute lymphoblastic leukemia (ALL). Exposure to influenza or RSV seasons later in infancy, especially for firstborns, was linked to increased ALL risk.
Area of Science:
- Pediatric oncology
- Epidemiology
- Immunology
Background:
- Epidemiologic studies suggest early childhood infections may offer protection against pediatric acute lymphoblastic leukemia (ALL).
- The hygiene hypothesis is a proposed mechanism for this protective effect.
Purpose of the Study:
- To investigate the association between early life infection exposure and the risk of pediatric ALL.
- To examine specific infection timing (influenza, RSV) and birth order as potential risk factors.
Main Methods:
- Identified 3,402 pediatric ALL cases (ages 0-5) and 20:1 matched controls using California Cancer Registry and birth records.
- Analyzed markers of infection exposure: birth month, timing relative to influenza/RSV seasons, and birth order.
- Utilized California birth certificates and national infection surveillance data.
Main Results:
- Increased ALL risk observed for spring/summer births.
- Higher ALL risk associated with first exposure to influenza or RSV seasons at 9-12 months versus 0-3 months (OR 1.44 for influenza).
- This association was stronger in firstborn children. Decreased risk with higher birth order noted in non-Hispanic whites, but not Hispanics.
Conclusions:
- Findings support the hypothesis that early childhood infections decrease the risk of pediatric ALL.
- Early life exposure to infections appears to be a protective factor against ALL in young children.
Background:
Epidemiologic studies indicate that infections in early childhood may protect against pediatric acute lymphoblastic leukemia (ALL).
Methods:
We identified 3,402 ALL cases among children 0 to 5 years of age using the California Cancer Registry. From California birth records we randomly selected controls in a 20:1 ratio and frequency matched them to cases by birth year. We investigated markers of exposure to infections, including month of birth, timing of birth in relation to influenza and respiratory syncytial virus (RSV) seasons, and birth order based on data from California birth certificates and national infection surveillance systems.
Results:
We observed an increased risk of ALL for spring and summer births, and for those first exposed to an influenza or RSV season at nine to twelve months of age compared with those exposed during the first three months of life, and this association was stronger among first born children [odds ratios (OR), 1.44 and 95% confidence intervals (CI), 1.13-1.82, for influenza exposure at nine to twelve months of age]. Decreased risk was observed with increasing birth order among non-Hispanic whites but not Hispanics (OR, 0.76 and 95% CI, 0.59-096, for fourth or higher birth order among whites).
Conclusion:
Our results support the hypothesis that infections in early childhood decrease risk of ALL.
Impact:
Our findings implicate early life exposure to infections as protective factors for ALL in young children.
Related Concept Videos
01:25Immunodeficiency Diseases
There are three main causes of immunodeficiency...
01:27Disorders of Leukocytes
Leukopenia may result from bone marrow disorders, autoimmune diseases, and infectious diseases. For example, conditions such as multiple myeloma and aplastic anemia can impair the bone marrow's ability to produce adequate leukocytes. Similarly, autoimmune diseases like lupus and viral infections such as HIV can prompt the immune...
01:26Factors Affecting the Risk of Infection
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin...
01:51Vaccinations
02:59Cancer Prevention
Some...
01:22Development of Immunocompetence
The initial cells that migrate from the fetal thymus settle within the skin and epithelial tissues lining the mouth, digestive tract, and in females, the uterus and vagina. These cells, including skin-based dendritic cells, serve as antigen-presenting cells, playing a key role in T cell activation.
Subsequent T...