Parental age, family size, and offspring's risk of childhood and adult acute leukemia
Cancer Epidemiology, Biomarkers & Prevention,

Larfors G et al. – The results support the idea of a prenatal etiology of leukemia but indicate that parental age effects are limited to childhood cases.

• In this register-based case–control study, we examined the association between parental age and incidence of acute leukemia in 2,660 childhood cases and 4,412 adult cases of acute leukemia, compared with 28,288 age-matched controls selected from a population-based register.
• Relative risks were estimated with conditional logistic regression.

• We found a small increased risk of childhood acute lymphoblastic leukemia with increasing paternal age (adjusted OR, 1.05 per 5-year increase in age).
• Risk estimates were similar for childhood acute myeloid leukemia (AML), whereas no association was found with adult leukemia.
• Meanwhile, we observed a decreased risk of adult AML with increasing number of siblings, both older and younger.