Penn IW, et al. - Using data obtained from a nationwide healthcare database, researchers conducted a retrospective, longitudinal cohort study to examine the connection between migraine and fibromyalgia (FM). There were two arms in this study—Arm 1, which included 33,216 subjects with FM, and Arm 2, which consisted of 7420 subjects with migraine. All subjects received their diagnoses between 2000 and 2010. In the FM cohort, the overall incidence of migraine was higher than in the corresponding control cohort. The overall incidence of FM in the migraine cohort was 1.57 times greater than that in the corresponding control cohort after adjustment for sex, age and comorbidities. Overall, a bidirectional connection was evident between FM and migraine.