Corrigendum

Table 2

In the first column (Variables), the lowest interval level for ferritin was given as:

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Table 2

Prevalence odds ratio (OR) for headache with 95% confidence interval (CI) related to haemoglobin and ferritin (adjusted for age and level of education)

Variables		Total no.	All headache types			Migraine			Non-migrainous headache
			n	OR	95% CI	n	OR	95% CI	n	OR	95% CI
Hb (g/dl)	<11.5	76	35	0.6	0.4, 1.0	8	0.4	0.2, 0.9	27	0.9	0.6, 1.5
	11.5–15.5	2288	1326	1.0		471	1.0		855	1.0
	>15.5	21	14	1.5	0.6, 3.7	6	1.6	0.6, 4.2	8	1.0	0.4, 2.5
P-trend value			0.02			0.01			0.77
Ferritin (µg/l)	<10	247	140	0.9	0.7, 1.2	54	1.1	0.8, 1.5	86	0.9	0.7, 1.2
	10–14	212	127	1.1	0.8, 1.4	45	1.1	0.8, 1.5	82	1.0	0.8, 1.4
	14–110	1804	1044	1.0		363	1.0		681	1.0
	>110	122	64	0.9	0.6, 1.2	23	1.0	0.6, 1.6	41	0.9	0.6, 1.3
P-trend value			0.93			0.55			0.68

Ferritin (µg/l) > 10

This value was incorrect and the text should have read:

Ferritin (µg/l) < 10

The corrected version of Table 2 appears below.

The authors apologize for this error.