The association of headache frequency with pain interference and the burden of disease is mediated by depression and sleep quality, but not anxiety, in chronic tension type headache

Table 1 Demographic variables and pearson-product moment correlation matrix for each study variable

	Mean	95% CI	1	2	3	4	5	6	7	8
1. Headache frequency (days/month)	18.1	17.5–18.7
2. Headache intensity (0–10)	5.9	5.5–6.3	.145^*
3. Headache duration (hours/attack)	7.3	6.6-8.0	.249**	n.s
4. Pittsburg Questionnaire (0–21)	17.1	15.8–18.4	.223^**	.177^**	.165*
5. HDI-E (0–52)	18.7	17.0–20.4	.341^**	.212^**	.350**	.328^**
6. HDI-P (0–48)	22.5	20.9–24.1	.235^**	.165^*	.237**	.232^**	.828^**
7. Bodily Pain (0–100)	51.2	47.9–54.6	-.245^**	-.165^*	n.s.	-.350^**	-.409^**	-.442^**
8. HADS-D (0–21)	8.0	7.5–8.6	.274^**	.227^**	.313**	.426^**	.538^**	.405^**	-.389^**
9. HADS-A (0–21)	10.0	9.3-10.7	n.s.	n.s	n.s	n.s	n.s	n.s	n.s	.208**

95% CI: 95% confidence interval
HDI Headache Disability Inventory (E Emotional, P Physical), HADS Hospital Anxiety and Depression Scale (D Depression, A Anxiety)
*P < 0.05; **P < 0.01

ISSN: 1129-2377