title: Parental age and risk of childhood cancers: a population-based cohort study from Sweden.
abstract: BACKGROUND
  Frequent germ line cells mutations were previously demonstrated to be associated with aging. This suggests a higher incidence of childhood cancer among children of older parents. A population-based cohort study of parental ages and other prenatal risk factors for five main childhood cancers was performed with the use of a linkage between several national-based registries.
  
  
  METHODS
  In total, about 4.3 million children with their parents, born between 1961 and 2000, were included in the study. Multivariate Poisson regression was used to obtain the incidence rate ratios (IRR) and 95% confidence interval (CI). Children <5 years of age and children 5-14 years of age were analysed independently.
  
  
  RESULTS
  There was no significant result for children 5-14 years of age. For children <5 years of age, maternal age were associated with elevated risk of retinoblastoma (oldest age group's IRR = 2.39, 95%CI = 1.17-4.85) and leukaemia (oldest age group's IRR = 1.44, 95%CI = 1.01-2.05). Paternal age was significantly associated with leukaemia (oldest age group's IRR = 1.31, 95%CI = 1.04-1.66). For central nervous system cancer, the effect of paternal age was found to be significant (oldest age group's IRR = 1.69, 95%CI = 1.21-2.35) when maternal age was included in the analysis.
  
  
  CONCLUSIONS
  Our findings indicate that advanced parental age might be associated with an increased risk of early childhood cancers.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 171 77 Stockholm, Sweden.
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Yip
authors.forename: Yudi
authors.initials: Y
authors.lastname: Pawitan
authors.forename: Kamila
authors.initials: K
authors.lastname: Czene
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D016543:Central Nervous System Neoplasms / Q000453:epidemiology / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000453:epidemiology / Q000209:etiology; D007938:Leukemia / Q000453:epidemiology / Q000209:etiology; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology / Q000209:etiology; D008297:Male; D008423:Maternal Age; D009369:Neoplasms / Q000453:epidemiology / Q000209:etiology*; D010331:Paternal Age; D011159:Population Surveillance / Q000379:methods; D019572:Retinal Neoplasms / Q000453:epidemiology / Q000209:etiology; D012175:Retinoblastoma / Q000453:epidemiology / Q000209:etiology; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D009396:Wilms Tumor / Q000453:epidemiology / Q000209:etiology