The study, entitled, “Long working hours, socioeconomic status, and the risk of incident type 2 diabetes: a meta-analysis of published and unpublished data from 222 120 individuals” was published in September issue of The Lancet Diabetes & Endocrinology.
The authors performed meta analysis of four published studies in the PubMed and Embase databases (until April 30, 2014) together with unpublished individual-level data from 19 studies retrieved from Working-Populations Consortium and Open-access International archives. In total, the data analyzed belonged to 222,120 individuals (men and women) from the US, Europe, Japan, and Australia.
The authors found that stratifying the analyzed population by socioeconomic status, the individuals of low socioeconomic status with longer working hours (≥55 h per week, when compared with 30-40h) had an increase of 30% in the risk of developing type 2 diabetes. In the high socioeconomic status group, no association was found. This analysis was performed excluding health behaviors, age and sex, and shift work (previously linked to increasing risk for obesity and diabetes).
This study represents a key stepping-stone for further studies to evaluate the mechanisms linking long working hours and diabetes among low socioeconomic status jobs.
Professor Kivimäki, study first author noted, “The pooling of all available studies on this topic allowed us to investigate the association between working hours and diabetes risk with greater precision than has been previously possible. Although working long hours is unlikely to increase diabetes risk in everyone, health professionals should be aware that it is associated with a significantly increased risk in people doing low socioeconomic status jobs.”
Dr. Orfeu Buxton, Pennsylvania State University, PA, and Dr Cassandra Okechukwu, Harvard School of Public Health, MA, commented, “Kivimäki and colleagues’ elegantly designed study provides a solid foundation for both epidemiological and intervention work on diabetes risks. The results remained robust even after controlling for obesity and physical activity, which are often the focus of diabetes risk prevention, suggesting that work factors affecting health behaviors and stress may need to be addressed as part of diabetes prevention.”