RESUMO
PURPOSE: The decreased level of melatonin, the substance involved in the control of the sleep-wake cycle, has been reported among the patients with age-related macular degeneration (AMD). However, knowledge about the relationship between sleep disturbance and AMD is still limited. This longitudinal case-control study aims to investigate the risk of incident AMD among the patients with clinically diagnosed insomnia using the Taiwan National Health Insurance Research Database. METHODS: The insomnia cohort (n = 15 465) consisted of newly diagnosed insomnia cases aged ≥55 years between 2000 and 2009. Subjects without insomnia, matched for age, gender and enrolment time, were randomly sampled as the control cohort (n = 92 790). Cox proportional hazard regressions were performed to calculate the hazard ratios (HR) of incident AMD for the two cohorts after adjusting for potential confounders. RESULTS: Of the 108 255 sampled subjects, 2094 (1.9%) were diagnosed with AMD, including 214 (0.2%) with neovascular AMD, during a mean follow-up period of 5.1 ± 2.8 years. Insomnia patients were more likely to have subsequent AMD than those without insomnia (2.5% versus 1.8%, p < 0.001). Further, the incidence of exudative AMD was also higher in the insomnia cohort than the control cohort (0.3% versus 0.2%, p = 0.002). The adjusted HR was 1.33 (95% confidence interval [CI], 1.18-1.48, p < 0.001) for AMD and 1.67 (95% CI, 1.20-2.33, p = 0.002) for exudative AMD. CONCLUSIONS: Clinically diagnosed insomnia is an independent indicator for the increased risk of subsequent AMD development.