Bidirectional association between migraine and depression among probands and unaffected siblings: A nationwide population-based study

Background: Evidence suggests a bidirectional association between migraine and depression in individuals and in twins. However, whether a bidirectional association between migraine and depression also occurs among siblings (probands and unaffected nontwin siblings) remains unknown. Methods: Using the Taiwan National Health Insurance Research Database, we examined the data of 1504 probands with migraine, 1595 unaffected siblings, and 6380 nonmigrainous controls born before 2000 to identify new-onset depression for the period between 1996 and 2011. Conversely, 31824 probands with depression, 34325 unaffected siblings, and 137300 nondepressive controls were examined for the identification of new-onset migraine. Results: Logistic regression analyses demonstrated that compared with the controls, patients with migraine (odds ratio [OR]: 4.09; 95% confidence interval [CI]: 3.75–4.46) and unaffected siblings (OR: 1.40; 95% CI: 1.24–1.58) were more likely to develop depression during the follow-up period. Moreover, patients with depression and unaffected siblings had a 4.13-fold (95% CI: 3.18–5.36) and 1.45-fold (95% CI: 1.03–2.05) increased risk of migraine. Discussion: The bidirectional association between migraine and depression among probands and unaffected siblings suggests a familial coaggregation of these two conditions. Additional studies are required to investigate the genetic and environmental etiologies for this coaggregation.