. 2009 Dec 3;36(2):219–228. doi: 10.1093/schbul/sbp147

Table 1.

Eight Ecological Studies from Europe, America, and Australia (Type A Studies) of Schizophrenia Risk for Subjects In Utero in the First, Second, or Third Trimester of Prenatal Life During the 1957 Pandemic of A2 Influenza

First Author and Publication Year	Region	N^a	End of Follow-up Period	Timing of Birth of Control Patients	Relative Risk by Trimester of Exposure
First Author and Publication Year	Region	N^a	End of Follow-up Period	Timing of Birth of Control Patients	1st	2nd	3rd
Mednick, 1988	Uusimaa County, Finland	58	1984	6 previous y	0.88	0.85	0.77
Kendell, 1989	Scotland	170	1988	2 previous y	0.87	0.81	0.90
O’Callaghan, 1991	Regions of England and Wales	263	1984	2 previous and 2 subsequent y	0.84	1.24	1.15
Torrey, 1991	10 U.S. states	3368	1987/1988	1 previous and 1 subsequent y	0.95	1.00	1.07
Erlenmeyer-K, 1994	Croatia	82	1990	2 previous and 2 subsequent y	0.90	0.98	1.11
Selten, 1994	The Netherlands	654	1991	2 previous and 2 subsequent y	0.86	0.99	1.01
McGrath, 1994	Queensland, Australia	156	1988	5 previous and 5 subsequent y^b	0.57	1.27	1.21
Morgan, 1997	Western Australia	72	1996	1 previous and 1 subsequent y^c	0.86	1.00	1.86

Number of patients born in period of 9 months after pandemic.

Except 1954, 1957, and 1959.

See Morgan et al¹⁸ for details.