Table 2.

Summary of results of pooled ORs about the association between ADHD and headache in the main and in the subgroup meta-analyses

Type of analysis	Studies (n)	Participants (n)		OR	95% CI	p	Heterogeneity				Egger's test
							τ2	Q	p	I2 (%)	t	p
Review question 1		ADHD	Control
Overall crude OR	12	267 556	2 464 878	2.01	1.63–2.46	<0.001	0.11	92.70	<0.001	93.1	−1.79	0.104
Adjusted ORa	4	5229	60 112	1.98	1.60–2.45	<0.001	0.33	7.81	0.050	64.7	−0.31	0.789
Migraine	5	259 782	2 362 651	2.22	1.76–2.79	<0.001	0.04	10.38	0.035	67.6	−0.94	0.418
Tension headache	3	534	7221	0.80	0.57–1.12	0.196	0.03	3.38	0.185	36.5	1.07	0.478
Review question 2		Treatment	Placebo
Amphetamine	10	1780	892	1.05	0.80–1.38	0.723	0.04	11.26	0.258	21.53	2.10	0.069
Atomoxetine	22	2387	1470	1.29	1.06–1.56	0.010	0	18.90	0.528	0	1.27	0.221
Maximum dosage < 1.5 mg/kg	9	902	620	1.53	1.01–2.30	0.043	0.11	12.76	0.240	28.7	1.37	0.214
Maximum dosage ⩾ 1.5 mg/kg	13	1485	850	1.22	0.96–1.54	0.105	0	7.88	0.724	0	0.16	0.878
Forced titration	11	1368	708	1.33	1.01–1.75	0.041	0.02	13.26	0.209	8.46	−0.11	0.918
Flexible/optimized dose	11	1019	762	1.24	0.93–1.65	0.148	0	5.51	0.788	0	2.66	0.029
Bupropion	1	53	52	0.79	0.33–1.93	0.613
Clonidine	1	31	30	1.73	0.38–7.99	0.482
Guanfacine	8	1275	681	1.43	1.12–1.82	0.005	0	4.17	0.760	0	2.05	0.086
Methylphenidate	17	2077	1294	1.33	1.09–1.63	0.005	0	10.96	0.812	0	−0.58	0.570
Monotherapy with oral formation	15	1781	1070	1.41	1.12–1.78	0.003	0	9.81	0.776	0	−1.22	0.245
OROS/extended release	13	1793	1132	1.37	1.11–1.70	0.003	0	7.74	0.805	0	0.57	0.578
Immediate release	3	139	90	1.00	0.33–3.00	0.999	0.28	2.38	0.305	27.3	−2.64	0.231
Modafinil	6	520	298	1.24	0.73–2.13	0.429	0.18	7.61	0.179	42.3	0.59	0.589

OROS, osmotic-release oral system.

^aAdjusted variables: Jameson et al. (2016), adjusted for age, sex, race, and parental education; Lateef et al. (2009), adjusted for sex, age, race, and poverty index ratio; Schieve et al. (2012), adjusted for age, sex, race, and maternal education; Strine, Okoro, McGuire, & Balluz. (2006), adjusted for age, sex, race, parental structure, poverty status, type of health care coverage, and number of comorbid conditions.