Table 5. Risk of neuropsychiatric adverse events associated with the use of montelukast over the preceding 7 days using control periods (3, 6 and 9 months before the index date).

First control period	Exposed in hazard period		Exposed in control period		Crude		P value	Adjusted		P value
	N/N	(%)	N/N	(%)	OR (95% CI)*			OR (95% CI)†
3 months before the index date	12 673/161 386	(7.85)	43 917/484 158	(9.07)	1.26	(1.23 to 1.30)	<0.0001	1.66	(1.62 to 1.71)	<0.0001
6 months before the index date	12 673/161 386	(7.85)	47 497/484 158	(9.81)	1.11	(1.08 to 1.14)	<0.0001	1.46	(1.42 to 1.49)	<0.0001
9 months before the index date	12 673/161 386	(7.85)	47 079/484 158	(9.72)	1.12	(1.10 to 1.15)	<0.0001	1.30	(1.27 to 1.34)	<0.0001

^*Calculated by conditional logistic regression.

^†Calculated by conditional logistic regression adjusted for concomitant medications.