title: Season of birth and schizophrenia in Northeast Brazil: relationship to rainfall.
abstract: Although the association of schizophrenia and winter birth has been replicated many times in the Northern hemisphere, studies in the Southern hemisphere have been less consistent in their findings. A study from NE Brazil indicated the period between May and July, 3 months after the peak in rainfall, as a risk period for schizophrenia birth. We report findings from a random selection of charts (N = 1789) from the only public inpatient psychiatric facility in Ceará, Brazil (2 degrees to 5 degrees S). We compared the seasonality of birth in the schizophrenia group (N = 406) to multiple control groups: (1) psychosis not otherwise specified (N = 868), (2) other psychiatric diagnoses (N = 515), and (3) the average monthly birth rate in the general population. Patients with schizophrenia had a significantly greater risk of being born in the risk period compared with any of the control groups. There is a significant association between rainfall in a month and schizophrenia births 3 (p = 0.03) and 4 months (p = 0.01) later. This study corroborates findings of a significant seasonality in schizophrenia births in northeast Brazil.
authors.affiliation: School of Medicine, Federal University of Ceará, Fortaleza CE, Brazil. emessias@jhsph.edu
authors.forename: Erick
authors.initials: E
authors.lastname: Messias
authors.forename: Carine
authors.initials: C
authors.lastname: Mourao
authors.forename: Juliana
authors.initials: J
authors.lastname: Maia
authors.forename: Joao Paulo Mendes
authors.initials: JP
authors.lastname: Campos
authors.forename: Kersia
authors.initials: K
authors.lastname: Ribeiro
authors.forename: Luciana
authors.initials: L
authors.lastname: Ribeiro
authors.forename: Brian
authors.initials: B
authors.lastname: Kirkpatrick
mesh_terms: D001723:Birth Rate; D001938:Brazil / Q000453:epidemiology; D002980:Climate; D006801:Humans; D011891:Rain; D012559:Schizophrenia / Q000453:epidemiology*; D012621:Seasons