Chronic Melatonin Use Linked to Elevated Heart Failure Risk

A large, observational study using de-identified health records found that adults with chronic insomnia who used melatonin for at least 12 months had about a 90% higher five-year risk of developing heart failure (4.6% vs 2.7%), plus higher rates of heart-failure-related hospitalization (19.0% vs 6.6%) and all-cause death (7.8% vs 4.3%). The results do not prove causation and could be influenced by unmeasured factors or misclassification of OTC melatonin use; researchers call for more research and cautious discussion of long-term melatonin use with patients.