TABLE 1. Risk Factors (Known, Suggestive, Limited) Associated With Childhood Leukemias and Lymphomas

Exposure or Characteristic Leukemia

Lymphoma

Acute Lymphoblastic Acute Myeloid Hodgkin Disease Non-Hodgkin Lymphoma

Known
 Gender M:F = 1.3 M:F = 1.1 M:F = 1.3 M:F = 3.0
 Age peak 2–4 years Infancy Adolescence Adolescence
 Age-adjusted incidence 26.3 per million 6.5 per million 13.8 per million 9.9 per million
 Race W:B = 2.0 W:B = 1.0 W:B = 1.3 W:B = 1.4
 Other factors Birth weight >4000 g Monozygotic twins of Immunosuppressive therapy
 Ionizing radiation  young adults
  Diagnostic, in utero Affected siblings Congenital immunodeficiency
  Therapeutic, postnatal ALL and AML Epstein-Barr virus linked  syndromes (eg, ataxia,
 Down syndrome  with some forms  telangiectasia)
  ALL and AML M7
Congenital disorders, ataxia telangiectasia, Fanconi syndrome, Bloom syndrome, neurofibromatosis Infectious mononucleosis AIDS
Suggestive Maternal fetal loss Maternal alcohol use during pregnancy
Mother older than 35 years at pregnancy
First born Parental occupational exposures
- Benzene
- Pesticides
Limited Paternal smoking before Maternal marijuana use Residential exposures
 conception  during pregnancy  Pesticides
Parental occupational exposures Parental occupational exposures
 Hydrocarbons  Pesticides
 Paints
 Motor vehicle exhaust
60-Hz magnetic fields Residential exposures
 >0.4 µT  Pesticides
Postnatal chloramphenicol use
Clustering
Decreased risk associated with breastfeeding

M:F indicates male-to-female ratio of incidence; W:B, white-to-black ratio of incidence; AML, acute myeloid leukemia; AIDS, acquired immunodeficiency syndrome.