Shift work migraine disorder: evidence, mechanisms, and implications for diagnosis, prevention, and management.

INTRODUCTION/BACKGROUND: Migraine is the leading neurological disorder and the second leading cause of years of life lived with disability (YLDs), affecting roughly 14–15% of the global population. The recognized importance of circadian rhythm disruption, sleep disorders, and occupational stressors as migraine triggers provides justification for studying shift work in connection to migraine. Circadian rhythm disruption has been shown to increase the risk of migraine, with shift workers experiencing a higher prevalence as compared to non-shift workers. The goal of this review is to support viewing “Shift Work Migraine Disorder” as a possible distinct chrono-neurological subtype of migraine. RESULTS: Epidemiological studies consistently show that night and rotating shift workers have higher migraine prevalence compared with non-shift workers, with meta-analytic estimates indicating more than a 60% increased risk, OR = 1.61, and a 63% increased incidence of migraine, HR = 1.63. Dose-response relationship indicates that a higher number or longer duration of night shifts is associated with a greater risk of developing migraine. Circadian misalignment, reduced melatonin secretion, and sleep disturbances, including insomnia and shift work disorder, are strongly implicated in migraine pathophysiology among shift workers. Neuroimaging, hormonal and genetic evidence implicate common pathways in the hypothalamus, brainstem and suprachiasmatic nucleus (SCN). Clinically, migraine attacks in shift workers are characterized by timing and frequency patterns related to night and rotating schedules, with higher comorbidity of insomnia, anxiety, and metabolic disruption. Diagnosis is limited by the absence, within present classification systems, of criteria describing circadian misalignment and irregular shift patterns. CONCLUSION: Shift work, especially rotating and night shifts, greatly heightens migraine risk and burden; emerging evidence supports the concept of Shift Work Migraine Disorder as a distinct subtype. More longitudinal, neurobiological, and diagnostic validation studies are needed to establish causality and optimize preventive and management strategies.