Maternal household crowding during pregnancy and the offspring's risk of schizophrenia.
BACKGROUND
Animal models of schizophrenia suggest a link between maternal crowding during pregnancy and increased risk of the offspring to develop physiological, developmental, and behavioral abnormalities that are comparable to those observed in schizophrenia. We tested the hypothesis that a similar link is present in humans.


METHODS
We investigated whether prenatal exposure to household crowding was associated with the risk of schizophrenia in a sub-cohort of the Jerusalem Perinatal Study (JPS) consisting 11,015 individuals born between 1964 and 1976. During these years mothers participated in face to face interviews in early pregnancy. The prenatal and birth data, including the number of rooms and individuals living in the mothers' household, was cross-linked with the Israel Psychiatric Registry by ministry personnel.


RESULTS
104 schizophrenia cases were identified in the cohort. Offspring who, while in utero, their mother resided in a household with five or more individuals had RR of 1.47 (95% CI: 0.99-2.16, p=0.05) to develop schizophrenia, compared to those whose mother resided with four or fewer individuals. However, when adjusted for paternal age, the RR was reduced to 1.18 (95% CI: 0.76-1.84, p=0.46). The number of rooms in the household and the household crowding during pregnancy did not significantly impact the offspring's risk to develop schizophrenia.


CONCLUSIONS
The link between maternal household crowding during pregnancy and the offspring's risk of schizophrenia was explained primarily by the impact of paternal age. The authors discuss the results in view of findings from animal and human studies.
Kimhy
David
D
Department of Psychiatry, Columbia University, New York, NY 10032, USA. dk553@columbia.edu
Harlap
Susan
S
Fennig
Shmuel
S
Deutsch
Lisa
L
Draiman
Benjamin G
BG
Corcoran
Cheryl
C
Goetz
Deborah
D
Nahon
Daniella
D
Malaspina
Dolores
D
D015331:Cohort Studies; D018672:Community Health Planning / Q000379:methods; D003441:Crowding; D019992:Databases as Topic / Q000706:statistics & numerical data; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007557:Israel; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D011297:Prenatal Exposure Delayed Effects; D012042:Registries / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012306:Risk; D012559:Schizophrenia / Q000453:epidemiology / Q000209:etiology*; D012565:Schizophrenic Psychology