HEALTHYSHIFTWORK: a comprehensive longitudinal study of shift work and determinants of non-communicable diseases

Research problem and specific questions: Long-term disruption of circadian rhythms, particularly due to light exposure during the biological night, is associated with a wide range of common non-communicable diseases (NCDs).

Approximately 12% of the European working population engages in night-shift work; therefore, studying the impact of night-shift work has important implications for public health.

The proposed study aims to a) collect individual-level data on multiple exposures among night-shift workers, using new sensors, information technology, and advanced biomonitoring; b) examine how short-term night-shift work affects bodily functions related to the development of NCDs and ageing; c) identify key biological pathways for health effects associated with night-shift work; d) evaluate longitudinal changes in biomarkers among night- and day-shift workers from baseline to a two-year follow-up; and e) develop a screening battery relevant to night-shift work and development of NCDs to be implemented in the pre-assignment and periodical medical examination conducted by the occupational health services.Data and method: We will address these aims by collecting comprehensive information about occupational and environmental exposures, lifestyle factors, and dietary patterns.

We will measure cognitive function, established biomarkers of cardiovascular and metabolic health, hormones, stress, immune function, ageing and epigenetic programming in blood, saliva, and adipose tissue of night- and day-shift workers.Plan for project realization: At baseline, we will compare night- with day-shift workers among Swedish workers (county council health workers n=400) and European workers (n=800) examined with the same protocol during a work week, and we will follow up the Swedish workers (n=400) two years later applying the same protocol.Relevance: This study will generate new knowledge of the long-term impact of circadian disruption on determinants of NCDs and identify the important biological pathways underlying health outcomes among night-shift workers.

This will inform preventive actions such as improved work schedules, medical surveillance via the occupational health service of exposed populations, and advising exposed workers.