25 Sep Longer Working Hours Linked To Increased Risk of Diabetes in Lower Socioeconomic Jobs

MedicalResearch.com Interview with:
Prof Mika Kivimäki PhD
Department of Epidemiology and Public Health,
University College London, London, UK
Hjelt Institute, Medical Faculty, University of Helsinki, Helsinki, Finland

Medical Research: What are the main findings of the study?

Prof. Kivimäki: In our study, we pooled published and unpublished data from 222 120 men and women from the USA, Europe, Japan, and Australia. Of them, 4963 individuals developed type 2 diabetes during the mean follow-up of 7.6 years. This is the largest study to date on this topic.

In an analysis stratified by socioeconomic status, the association between long working hours and diabetes was evident in the low socioeconomic status group, but was null in the high socioeconomic status group. The association in the low socioeconomic status group did not change after taking into account age, sex, obesity, physical activity, and shift working. So, the association was very robust.

In brief, the main finding of our meta-analysis is that the link between longer working hours and type 2 diabetes was apparent only in individuals in the low socioeconomic status groups.

Medical Research: What was most surprising about the results?

Prof. Kivimäki: The socioeconomic patterning in these results. The higher the person’s position in the socioeconomic hierarchy, the less working long hours was linked to type diabetes. Why high socioeconomic position protects against the diabetogenic effects of long working hours is unclear.

Medical Research: What should clinicians and patients take away from your report?

Prof. Kivimäki: Treating physicians should be aware that in low socioeconomic groups individuals who work 55 h or more per week have almost 30% higher risk of developing diabetes than those who worked 35–40 h per week.

Medical Research: What recommendations do you have for future research as a result of this study?

Prof. Kivimäki: It is unclear what specific aspects in low socioeconomic status jobs increase the risk of diabetes. Future studies should examine these.
Citation:

Working long hours linked to increased risk of type 2 diabetes in people doing low socioeconomic status jobs

Mika Kivimäki, Marianna Virtanen, Ichiro Kawachi, Solja T Nyberg, Lars Alfredsson, G David Batty, Jakob B Bjorner, Marianne Borritz, Eric J Brunner, Hermann Burr, Nico Dragano, Jane E Ferrie, Eleonor I Fransson, Mark Hamer, Katriina Heikkilä, Anders Knutsson, Markku Koskenvuo, Ida E H Madsen, Martin L Nielsen, Maria Nordin, Tuula Oksanen, Jan H Pejtersen, Jaana Pentti, Reiner Rugulies, Paula Salo, Johannes Siegrist, Andrew Steptoe, Sakari Suominen, Töres Theorell, Jussi Vahtera, Peter J M Westerholm, Hugo Westerlund, Archana Singh-Manoux, Markus Jokela

The Lancet Diabetes & Endocrinology, Early Online Publication, 25 September 2014

doi:10.1016/S2213-8587(14)70178-0

Last Updated on September 25, 2014 by Marie Benz MD FAAD