Childhood lymphohematopoietic cancer incidence and hazardous air pollutants in southeast Texas, 1995-2004.
BACKGROUND
Cancer is the second leading cause of death among U.S. children with few known risk factors. There is increasing interest in the role of air pollutants, including benzene and 1,3-butadiene, in the etiology of childhood cancers.


OBJECTIVE
Our goal was to assess whether census tracts with the highest benzene or 1,3-butadiene ambient air levels have increased childhood lymphohematopoietic cancer incidence.


METHODS
Our ecologic analysis included 977 cases of childhood lymphohematopoietic cancer diagnosed from 1995-2004. We obtained the U.S. Environmental Protection Agency's 1999 modeled estimates of benzene and 1,3-butadiene for 886 census tracts surrounding Houston, Texas. We ran Poisson regression models by pollutant to explore the associations between pollutant levels and census-tract cancer rates. We adjusted models for age, sex, race/ethnicity, and community-level socioeconomic status (cSES).


RESULTS
Census tracts with the highest benzene levels had elevated rates of all leukemia [rate ratio (RR) = 1.37; 95% confidence interval (CI), 1.05, 1.78]. This association was higher for acute myeloid leukemia (AML) (RR = 2.02; 95% CI, 1.03-3.96) than for acute lymphocytic leukemia (ALL) (RR = 1.24; 95% CI, 0.92-1.66). Among census tracts with the highest 1,3-butadiene levels, we observed RRs of 1.40 (95% CI, 1.07-1.81), 1.68 (95% CI, 0.84-3.35), and 1.32 (95% CI, 0.98-1.77) for all leukemia, AML, and ALL, respectively. We detected no associations between benzene or 1,3-butadiene levels and lymphoma incidence. Results that examined joint exposure to benzene and 1,3-butadiene were similar to those that examined each pollutant separately.


CONCLUSIONS
Our ecologic analysis suggests an association between childhood leukemia and hazardous air pollution; further research using more sophisticated methodology is warranted.
Whitworth
Kristina W
KW
Division of Epidemiology and Disease Control, University of Texas School of Public Health, Houston, Texas, USA.
Symanski
Elaine
E
Coker
Ann L
AL
D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology*; D012923:Social Class; D013781:Texas / Q000453:epidemiology; D014481:United States; D014484:United States Environmental Protection Agency
D000393:Air Pollutants