Parental age and the risk of childhood acute myeloid leukemia: results from the Childhood Leukemia International Consortium

Background: Parental age has been associated with several childhood cancers, albeit the evidence is still inconsistent. Aim: To examine the associations of parental age at birth with acute myeloid leukemia (AML) among children aged 0-14 years using individual-level data from the Childhood Leukemia International Consortium (CLIC) and non-CLIC studies. Material/methods: We analyzed data of 3182 incident AML cases and 8377 controls from 17 studies [seven registry-based case-control (RCC) studies and ten questionnaire-based case-control (QCC) studies]. AML risk in association with parental age was calculated using multiple logistic regression, meta-analyses, and pooled-effect estimates. Models were stratified by age at diagnosis (infants < 1 year-old vs. children 1-14 years-old) and by study design, using five-year parental age increments and controlling for sex, ethnicity, birthweight, prematurity, multiple gestation, birth order, maternal smoking and education, age at diagnosis (cases aged 1-14 years), and recruitment time period. Results: Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) derived from RCC, but not from the QCC, studies showed a higher AML risk for infants of mothers >= 40-year-old (OR = 6.87; 95% CI: 2.12-22.25). There were no associations observed between any other maternal or paternal age group and AML risk for children older than one year. Conclusions: An increased risk of infant AML with advanced maternal age was found using data from RCC, but not from QCC studies; no parental age-AML associations were observed for older children.