EuRhythDia II is a multicenter, randomized, double-blind controlled study. The rationale of EuRhythdia is to explore the effects of 12 weeks of timed melatonin treatment on circadian rhythm, metabolic control and cardiovascular function in night shift workers. The 12 weeks of intervention will be followed by 12 weeks of washing out.

Modern lifestyle has dramatically changed the daily rhythms of life. Physical activity, diet and light exposure are no longer restricted to daytime hours due to increased shift work. Recent scientific reports have shown that shift work leads to disruption of circadian rhythms and promotes diabetes, obesity and cardiovascular disease. Until now only few studies investigating circadian rhythm disturbances in the context of type 2 diabetes and obesity have been conducted in man. Thus, knowledge of the molecular pathways and the responsibles genes in man are missing and have been identified only in animal studies.

The objective of the project is to achieve breakthroughs in the understanding of the causality between inner clock rhythm disturbances and the development of type 2 diabetes and obesity. The provided data on the interaction between genes, epigenetics, metabolism, cardiovascular function and the internal clock are intended to contribute to identify novel biomarkers and novel therapeutic approaches focusing on circadian rhythms to reduce the occurence of diabetes and obesity in shift worker.

Inclusion Criteria:

• Male and female above the age of 18
• Night shift workers on regular night shifts (at least 6 months before inclusion into the study and at least 4 night shifts per month during the study period

Exclusion Criteria:

• pregnancy or breast feeding
• Known autoimmune disease
• Current or relevant history of physical or psychiatric illness
• Evidence of renal insufficiency or liver disease
• Known or suspected intolerance or hypersensitivity to the study medication
• Use of certain drugs within 4 weeks prior to the inclusion to the study