Results obtained in this observational, analytical, and mixed design study support the conclusion that melatonin in high doses and for a relatively long period of time is associated with improvement in hypertension, ischemic heart disease and diabetes mellitus in aged individuals, although casualty cannot be inferred. Melatonin diminishes progressively with aging and is especially reduced in numerous chronic, age-related non-communicable diseases [13,14]. In humans, beyond its role in regulating circadian rhythms, melatonin demonstrates multifaceted protective functions in cardiovascular disease, involving antioxidant activity, modulation of inflammation, and epigenetic control [12].
This study demonstrates that long-term administration of high-dose melatonin (40–200 mg/day) in older adults with sleep disorders is well tolerated and suggests that it is associated with improvements in arterial hypertension, ischemic heart disease, and diabetes mellitus, alongside favorable modulation of alkaline phosphatase levels without other laboratory alterations. Long-term clinical studies evaluating the safety of high-dose melatonin in elderly patients remain scarce. While our study provides long-term data supporting the safety of high-dose melatonin in elderly patients, further studies are needed to fully establish its long-term risks. The observed improvement in the studied conditions should be interpreted as correlations rather than proof of a protective effect, although they are consistent with the cytoprotective potential of supraphysiological melatonin dosing for improving cardiovascular and metabolic health in the elderly. Future prospective, long-term, randomized trials are warranted to confirm safety and efficacy as well as to define optimal dosing strategies.