Working more than 55 hours a week at low-income jobs such as manual work is associated with an increased risk of developing Type 2 diabetes, according to a new study published in the journal The Lancet Diabetes & Endocrinology. Approximately 26 million people in the United States have Type 2 diabetes, and another 86 million have prediabetes.
To determine the health effects of working long hours at jobs of various socioeconomic statuses, researchers conducted a meta-analysis (a review of data from several clinical trials) from 23 published and unpublished studies involving more than 222,000 men and women from the United States, Europe, Japan, and Australia who were followed for an average of 7.6 years.
The researchers found that people working 55 hours a week or more at low-socioeconomic-status jobs had a roughly 30% increased risk of Type 2 diabetes compared to those working between 35 and 40 hours a week, even after taking risk factors such as age, sex, and obesity and health behaviors such as smoking and exercise into account. The link remained even after shift work, which has been shown to increase the risk of Type 2 diabetes, was excluded from the analysis. Working long hours at higher-income jobs was not found to be associated with an increased risk of developing Type 2 diabetes.
In a comment linked to the study, Orfeu M. Buxton, PhD, and Cassandra Okechukwu, ScD, MSN, who were not involved with the research, noted that “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.”
The researchers say that further study is needed to determine the underlying mechanisms that link working long hours at low-income jobs to developing Type 2 diabetes, but suggest that maintaining disruptive schedules that leave little time for healthful behaviors such as sleeping, relaxing, and exercising may play a role. They also propose that people working at low-socioeconomic-status jobs may be dealing with hardships not related to work, which could themselves be behind the increased diabetes risk.
“My recommendation for people who wish to decrease the risk of Type 2 diabetes applies both to individuals who work long hours and those who work standard hours: Eat and drink healthfully, exercise, avoid overweight, keep blood glucose and lipid levels within the normal range, and do not smoke,” said lead study author Mika Kivimäki, PhD.
For more information, read the article “Working long hours linked to increased risk of type 2 diabetes in people doing low socioeconomic status jobs” or see the study in The Lancet Diabetes & Endocrinology. And to learn more about steps you can take to prevent Type 2 diabetes, see this three–part series from certified diabetes educator Amy Campbell.