Low headache prevalence amongst women with high TSH values

The aim of this large cross-sectional population-based study was to examine a possible positive or negative association between thyroid dysfunction and headache. Between 1995 and 1997, all 92 566 adults in Nord-Trøndelag County in Norway were invited to participate in a health survey. A total of 51 383 (56%) responded to a headache questionnaire, whereof thyroid-stimulating hormone (TSH) was measured in 28 058 individuals. These included 15 465 women and 8019 men above 40 years of age, 1767 randomly selected individuals between 20 and 40 years of age, and 2807 (97%) with thyroid dysfunction. Associations between thyroid dysfunction and headache were assessed in multivariate analyses, estimating prevalence odds ratios (OR) with 95% confidence intervals (CIs). High TSH values were associated with low prevalence of headache. This was most evident amongst women with no history of thyroid dysfunction. Amongst these, headache was less probable (OR=0.5, 95% CI 0.3-0.7) if TSH > or = 10 mU/l than in women with normal TSH (0.2-4 mU/l). In all age groups between 40 and 80 years, TSH was lower amongst headache sufferers, especially migraineurs, than in those without headache complaints.