Working for more than 55 hours a week can increase the risk of type 2 diabetes, according to a new research.

Researchers at the University College London did a systematic review and meta-analysis of published studies and unpublished individual-level data by assessing the effects of long working hours on type 2 diabetes risk.

Long working hours have been associated with various health problems among employees. Citing a 2004 Bureau of Labor Statistics data, the Centers for Disease Control and Prevention states that nearly 15 million Americans work full time on evening shift, night shift, rotating shifts, or other employer arranged irregular shifts.

Stretched working hours can also have an impact on sleep and people with deprived sleep increase the risk of several chronic illnesses such as heart disease and gastrointestinal diseases.

The findings of the current study revealed that people doing low socioeconomic status jobs and working for at least 55 hours every week had a roughly 30 percent increased risk of developing diabetes as opposed to those who worked for 35 and 40 hours a week. Researchers took into account health behaviors such as smoking and physical activity, and other risk factors including age, sex, and obesity.

Researchers noted that this co-relation existed even after excluding shift work, which has been shown to increase the risk of obesity and developing type-2 diabetes.

"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," researcher Mika Kivimaki said in a press release.

The study was published in The Lancet Diabetes and Endocrinology.