title: Perinatal risk factors for acute myeloid leukemia.
abstract: Infectious etiologies have been hypothesized for acute leukemias because of their high incidence in early childhood, but have seldom been examined for acute myeloid leukemia (AML). We conducted the first large cohort study to examine perinatal factors including season of birth, a proxy for perinatal infectious exposures, and risk of AML in childhood through young adulthood. A national cohort of 3,569,333 persons without Down syndrome who were born in Sweden in 1973-2008 were followed up for AML incidence through 2010 (maximum age 38 years). There were 315 AML cases in 69.7 million person-years of follow-up. We found a sinusoidal pattern in AML risk by season of birth (P < 0.001), with peak risk among persons born in winter. Relative to persons born in summer (June-August), incidence rate ratios for AML were 1.72 (95 % CI 1.25-2.38; P = 0.001) for winter (December-February), 1.37 (95 % CI 0.99-1.90; P = 0.06) for spring (March-May), and 1.27 (95 % CI 0.90-1.80; P = 0.17) for fall (September-November). Other risk factors for AML included high fetal growth, high gestational age at birth, and low maternal education level. These findings did not vary by sex or age at diagnosis. Sex, birth order, parental age, and parental country of birth were not associated with AML. In this large cohort study, birth in winter was associated with increased risk of AML in childhood through young adulthood, possibly related to immunologic effects of early infectious exposures compared with summer birth. These findings warrant further investigation of the role of seasonally varying perinatal exposures in the etiology of AML.
authors.affiliation: Department of Medicine, Stanford University, 1265 Welch Road, MSOB X212, Stanford, CA, 94305-5411, USA. kccrump@stanford.edu.
authors.forename: Casey
authors.initials: C
authors.lastname: Crump
authors.affiliation: Center for Primary Health Care Research, Clinical Research Centre (CRC), Lund University, Building 28, floor 11, Jan Waldenströms gata 35, Skåne University Hospital, SE-205 02, Malmö, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Sundquist
authors.affiliation: Department of Health Research and Policy, Stanford University, HRP Redwood Building, T254B, Stanford, CA, 94305-5405, USA.
authors.forename: Weiva
authors.initials: W
authors.lastname: Sieh
authors.affiliation: Stanford Prevention Research Center, Stanford University, Medical School Office Building, 251 Campus Drive, Room X318, Stanford, CA, 94305-5411, USA.
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Winkleby
authors.affiliation: Center for Primary Health Care Research, Clinical Research Centre (CRC), Lund University, Building 28, floor 11, Jan Waldenströms gata 35, Skåne University Hospital, SE-205 02, Malmö, Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Sundquist
mesh_terms: D000328:Adult; D001722:Birth Order; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D047109:Fetal Development; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D015470:Leukemia, Myeloid, Acute / Q000453:epidemiology* / Q000209:etiology*; D008297:Male; D008423:Maternal Age; D018743:Perinatal Care; D011159:Population Surveillance; D011247:Pregnancy; D012042:Registries; D012307:Risk Factors; D012959:Socioeconomic Factors; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: Cohort studies; Fetal development; Gestational age; Leukemia; Risk factors; Seasons