Table 3.

Odds ratios for logistic regression modelling of age at diagnosis (under age 18) within the attention-deficit hyperactivity disorder cohort

Effect	OR (95% CI)	P
Sex
Female	Reference	—
Male	2.329 (2.015 to 2.691)	<0.001
Region of residence
Urban	Reference	—
Rural	1.327 (1.127 to 1.563)	0.001
Income quintile
Q1	1.245 (1.002 to 1.547)	0.048
Q2	1.233 (0.992 to 1.532)	0.06
Q3	1.453 (1.155 to 1.827)	0.001
Q4	1.195 (0.963 to 1.484)	0.11
Q5	Reference	—
Linear trend	0.86	0.06

Q1 to Q5 = income quintiles, with Q1 being the lowest and Q5 the highest