Shift Work Linked To Cognitive Impairment in Middle Aged and Older Adults Interview with:

Christian Benedict Ph.D Dept. of Neuroscience Uppsala University, Swedenphotographer: Magnus Bergström

Dr. Christian Benedict

Christian Benedict Ph.D
Dept. of Neuroscience
Uppsala University, Sweden What is the background for this study? What are the main findings?

Dr. Benedict: A considerably large proportion of today’s workforce performs shift work. Both epidemiological and experimental studies have demonstrated that shift workers are at an increased risk for multiple diseases, such as cardiovascular diseases. However, knowledge regarding short- and long-term effects of shift work on parameters of brain health is still fragmentary. What should readers take away from your report?

Dr. Benedict: Our results indicate that shift work is linked to poorer performance on a test* that is frequently used to screen for cognitive impairment in humans. This was only observed in current shift workers and those who worked shifts during the past 5 years. In contrast, no difference was observed between non-shift workers and those who had quit shift work more than 5 years ago. The latter could suggest that it may take at least 5 years for previous shift workers to recover brain functions that are relevant to the performance on this test.

*The Trail Making Test used in this study consists of two parts. Part A requires participants to connect circles labeled with numbers 1-25 in an ascending order. In part B, participants must alternate between numbers and letters in an ascending order. Time to complete these tests has been shown to increase with age. What recommendations do you have for future research as a result of this study?

Dr. Benedict: Based on our results I believe that shift workers represent an important target group in our society for preventive initiatives to promote brain health, e.g. regular physical exercise programs, nutrition courses, and anti-smoking campaigns. Is there anything else you would like to add?

Dr. Benedict: It must be kept in mind that the observed differences in the performance on this test between shift work groups were relatively small. Moreover, the finding that it may at least require a 5-year off-time period of shift work until humans can restore their executive functions must be interpreted with caution, given the cross-sectional design of our study. Thank you for your contribution to the community.


Olga E. Titova, Eva Lindberg, Sölve Elmståhl, Lars Lind, Helgi B. Schiöth, Christian Benedict. Association between shift work history and performance on the trail making test in middle-aged and elderly humans: the EpiHealth study. Neurobiology of Aging, 2016; DOI:10.1016/j.neurobiolaging.2016.05.007

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

More Medical Research Interviews on

[wysija_form id=”5″]



Last Updated on May 18, 2016 by Marie Benz MD FAAD