Table 2.

Regression coefficient estimates of attention-deficit hyperactivity disorder diagnosis

Model effect	Estimate	RR	95% CI	χ2a	P
Sex
Male	0.99	2.69	2.59 to 2.79	2799.69	<0.001
Female	Reference	—	—	—	—
Age group, years
18 to 19	0.72	2.05	1.93 to 2.18	537.05	<0.001
20 to 21	0.60	1.82	1.70 to 1.94	315.56	<0.001
22 to 23	0.51	1.66	1.55 to 1.78	221.14	<0.001
24 to 25	0.33	1.39	1.30 to 1.49	87.15	<0.001
26 to 27	0.20	1.22	1.14 to 1.32	30.58	<0.001
28 to 29	Reference	—	—	—	—
Region of residence by income quintile
Rural
Q1	−0.37	0.69	0.63 to 0.76	62.91	<0.001
Q2	−0.23	0.79	0.72 to 0.87	25.68	<0.001
Q3	−0.13	0.87	0.80 to 0.95	8.94	0.003
Q4	−0.07	0.93	0.86 to 1.02	2.34	0.13
Q5	Reference	—	—	—	—
Linear trend	0.30	1.35	1.26 to 1.45	74.70	<0.001
Urban
Q1	0.10	1.11	1.04 to 1.18	9.94	0.002
Q2	0.11	1.11	1.05 to 1.19	11.06	0.001
Q3	0.06	1.06	0.99 to 1.13	3.08	0.08
Q4	0.01	1.01	0.95 to 1.08	0.13	0.72
Q5	Reference	—	—	—	—
Linear trend	−0.10	0.91	0.86 to 0.95	17.21	<0.001

RR = relative risk; Q1 to Q5 = income quintiles, with Q1 being the lowest and Q5 the highest

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