Table 1.

Maternal and Paternal Infection During Pregnancy in a Cohort of 1 115 752 Persons Born Between 1978 and 1998 of Whom 3722 Developed Schizophrenia During 11.9 Million Person Years of Follow-Up

			Mother				Father
			IRRs (95% CIs)				IRRs (95% CIs)
Parental Infection During Pregnancy	Cases	Incidence Ratea	Basic Modelb	Adjusted Modelc	Casesd	Incidence Ratea	Basic Modelb	Adjusted Modelc
Infection	159	4.3	1.39 (1.18–1.62)	1.23 (1.04–1.44)	26	4.3	1.46 (0.97–2.10)	1.31 (0.87–1.88)
No infections	3563	3.1	1.00 (reference)	1.00 (reference)	3636	3.1	1.00 (reference)	1.00 (reference)

Note: IRR, incidence rate ratio.

^aThe incidence rate measures the number of new cases per 10 000 person years.

^bAdjusted for calendar year, sex, and its interaction with age.

^cFurther adjustment for family history of psychosis.

^dBecause of father unknown (N = 60, IRR not shown but included in the model), the numbers do not add up to the total number of cases in the sample.