Association of childhood leukemia with maternal age, birth order, and paternal occupation. A case-control study

Previous investigations have drawn conflicting conclusions concerning the association between childhood leukemia and maternal age, birth order, socioeconomic status, and paternal occupation. In this study, 255 childhood leukemia cases diagnosed in California between 1975 and 1980 were individually matched with two living controls on the basis of sex, date of birth, and county of birth. Data were derived from subjects' birth certificates. Socioeconomic status and paternal benzene exposure were determined from the paternal occupation stated on the birth certificate. Hispanics and males were overrepresented in the case group. Cases were also less likely to be of birth order one. No difference was found between case and control groups for maternal age or paternal occupation. Analyses with stratification on age, sex, and leukemia cell type are reported.