Current and cumulative night shift work and subclinical atherosclerosis: results of the Gutenberg Health Study

Abstract

Purpose: The study examines the association between exposure to current and cumulative night shift work and subclinical parameters of atherosclerosis.

Methods: Participants of a population-based cohort study (the Gutenberg Health Study, N = 15,010) aged 35-64 years were examined at baseline (2007-2012). Investigations included measurements of arterial stiffness, vascular function [reactive hyperaemia (RH) index], and intima media thickness (IMT). Also, a complete job history (including up to 15 periods), occupational exposures, a variety of lifestyle, and dispositional variables were enquired.

Results: Night shift work was performed by 1071 out of 8065 currently employed individuals. The strongest association after adjustment for age, sex, job complexity level, being a manager, overtime work, and noise appeared for more than 660 night shifts within the last 10 years and a significantly increased arterial stiffness of 0.33 m/s. This reflects a 4 % flow velocity increase for individuals with more than 660 night shifts compared to non-night workers. Regarding the entire professional life, night shift workers showed a significantly decreased vascular function by -0.054 RH index points by using the same adjustment. IMT values did not differ statistically from non-night workers. Lifestyle and dispositional factors showed an influence on all used subclinical atherosclerosis parameters.

Conclusions: The cross-sectional results demonstrate an association between night work and detrimental changes in the atherosclerotic process. The association is more pronounced with more years in night shift and is partly explained by lifestyle and dispositional factors. Longitudinal analyses are necessary to confirm the results.

Keywords: Arterial stiffness; Intima media thickness; Night shift work; Occupation; Population based; Vascular function.

Fig. 1

Association between cumulative night shift work during the last 10 years and arterial stiffness (in four statistical models). Percentage change in arterial stiffness and 95 % confidence intervals (CI) based on the ratio of subjects exposed to night shift and the unexposed reference group (basis of the comparisons: beta estimates (m/s) and 95 % CI)