Risk of leukemia in relation to exposure to ambient air toxics in pregnancy and early childhood.
There are few established causes of leukemia, the most common type of cancer in children. Studies in adults suggest a role for specific environmental agents, but little is known about any effect from exposures in pregnancy to toxics in ambient air. In our case-control study, we ascertained 69 cases of acute lymphoblastic leukemia (ALL) and 46 cases of acute myeloid leukemia (AML) from California Cancer Registry records of children <age 6, and 19,209 controls from California birth records within 2 km (1.3 miles) (ALL) and 6 km (3.8 miles) (AML) of an air toxics monitoring station between 1990 and 2007. Information on air toxics exposures was taken from community air monitors. We used logistic regression to estimate the risk of leukemia associated with one interquartile range increase in air toxic exposure. Risk of ALL was elevated with 3(rd) trimester exposure to polycyclic aromatic hydrocarbons (OR=1.16, 95% CI 1.04, 1.29), arsenic (OR=1.33, 95% CI 1.02, 1.73), benzene (OR=1.50, 95% CI 1.08, 2.09), and three other toxics related to fuel combustion. Risk of AML was increased with 3rd trimester exposure to chloroform (OR=1.30, 95% CI 1.00, 1.69), benzene (1.75, 95% CI 1.04, 2.93), and two other traffic-related toxics. During the child's first year, exposure to butadiene, ortho-xylene, and toluene increased risk for AML and exposure to selenium increased risk for ALL. Benzene is an established cause of leukemia in adults; this study supports that ambient exposures to this and other chemicals in pregnancy and early life may also increase leukemia risk in children.
Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA, USA. Electronic address: jeheck@ucla.edu.
Julia E
JE
Heck
Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA, USA.
Andrew S
AS
Park
Department of Biostatistics, Fielding School of Public Health, University of California, Los Angeles, CA, USA.
Jiaheng
J
Qiu
Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
Myles
M
Cockburn
Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA, USA.
Beate
B
Ritz
D000393:Air Pollutants / Q000009:adverse effects*; D001151:Arsenic / Q000009:adverse effects; D002070:Butadienes / Q000009:adverse effects; D002140:California; D016022:Case-Control Studies; D002675:Child, Preschool; D002725:Chloroform / Q000009:adverse effects; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006844:Hydrocarbons, Cyclic / Q000009:adverse effects; D007223:Infant; D015470:Leukemia, Myeloid, Acute / Q000209:etiology*; D016015:Logistic Models; D018811:Maternal Exposure / Q000009:adverse effects; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000209:etiology*; D011247:Pregnancy; D012307:Risk Factors; D012643:Selenium / Q000009:adverse effects; D001335:Vehicle Emissions / Q000633:toxicity
D000393:Air Pollutants; D002070:Butadienes; D006844:Hydrocarbons, Cyclic; D001335:Vehicle Emissions; D002725:Chloroform; D012643:Selenium; C031763:1,3-butadiene; D001151:Arsenic
Arsenic; Benzene; Childhood cancer epidemiology; Childhood leukemia; Chloroform; Lead; Polycyclic aromatic hydrocarbons; Pregnancy; Toluene; Xylenes