1. ¹Department of Biostatistics, Bioinformatics and Epidemiology, Medical University of South Carolina, 135 Cannon Street, Charleston, SC 29425, USA
2. ²Department of Epidemiology and Population Health, School of Public Health and Information Sciences, University of Louisville, 555 South Floyd Street, Room #4053, Louisville, KY 40202, USA
3. ³Lawton and Rhea Chiles Research Center, University of South Florida, 3111 E. Fletcher Avenue, Tampa, FL 33613-4660, USA
4. ⁴Department of Pediatrics, Medical University of South Carolina, 135 Rutledge Avenue, PO Box 250561, Charleston, SC 29425, USA
5. ⁵Department of Epidemiology and Biostatistics at Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA
6. ⁶Department of Environmental and Occupational Medicine, at Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 170 Frelinghuysen Road, Piscataway, NJ 08854-5635, USA

Correspondence: AS Adelman, E-mail: Aaron.Solomon.Adelman@gmail.com

Received 2 January 2007; Revised 16 April 2007; Accepted 20 April 2007; Published online 29 May 2007.

Abstract

We conducted an ecological analysis of childhood acute lymphoblastic leukaemia-incidence data from children 5 years old during 1992–1998 from the Surveillance, Epidemiology, and End Results Program in 200 counties and Hawaii. The response variable was the count of cases in each county race–sex stratum, examined in relation to data from the United States Census and the United States Department of Agriculture. The final models for both sexes included race, proportion moved during 1985–1990, and proportion of households with income $5000 as potential predictors. Incidence was lower among black boys (rate ratio (RR)=0.5) and black girls (RR=0.4) than among other children of the same sex; no other significant racial differences were detected. Incidence was elevated among males (but not females) residing in counties where 50% of the population relocated (RR=1.5) and among females (but not males) residing in counties where <6% of the households had incomes <$5000 (RR=1.5). These sex differences in risk factors were unexpected.