Melatonine en cardiovasculair risico: NHANES nuanceert recent hartfalen-signaal van AHA 2025

BACKGROUND: A large electronic health record study presented at the American Heart Association Scientific Sessions 2025 reported a heart failure safety signal associated with long-term melatonin use among adults with insomnia. In parallel, melatonin use has increased in the US general population, making counselling questions increasingly common in cardiovascular practice. MAIN ARGUMENT: Observational associations between melatonin and cardiovascular outcomes are unusually vulnerable to confounding-by-indication, reverse causality, and exposure misclassification because melatonin uptake often reflects insomnia severity, depression or anxiety symptoms and healthcare utilisation. EVIDENCE ANCHOR: In a nationally representative NHANES (National Health and Nutrition Examination Survey) adult cohort (1999-2018), melatonin users differed markedly from non-users at baseline, particularly for sleep disturbance and depression. In updated survey-weighted, multiple-imputation models, recent melatonin use was not significantly associated with prevalent composite cardiovascular disease or heart failure. These findings provide a hypothesis-generating contextual counterpoint to recent alarm signals rather than causal evidence of benefit or harm. CONCLUSION: Available observational data do not support strong claims of cardiovascular benefit, and they do not establish definitive cardiovascular harm or safety. Clinicians should document over-the-counter use, counsel pragmatically and prioritise evaluation and treatment of underlying sleep disorders while better evidence is developed.