Shift Work Ups Risk of Type 2 Diabetes, Especially in Men

Type-2 diabetes risk is higher in men working on rotating shift patterns, a new study reveals.

Several pieces of research conducted earlier have highlighted a strong association between rotating work shifts and increased risk of developing several health problems that include digestive disorders, certain cancers and cardiovascular disease. But, it was not known if this rotational shift pattern can cause diabetes.

The new study confirms that rotating work shifts is linked to a heightened risk of developing type-2 diabetes. The finding is based on the evaluation of the scientific research databases that looked at the association between shift work and diabetes risk.

The researchers focused on 12 international studies that involved 226,500 participants, out of which 14,600 had diabetes. On evaluating the results, researchers found that any period of shift work was linked with 9 percent increased risk of developing diabetes as compared to those working in normal office hours.

The risk increased by 37 percent for men. Although not much is known about the underlying cause of this risk, researchers assume that men working shift patterns might need to pay more attention to possible health consequences of their working schedule.

"Daytime levels of the male hormone testosterone are controlled by the internal body clock, so it's possible that repeated disruption may affect this," said the authors, pointing to research implicating low male hormone levels in insulin resistance and diabetes. "Most shift patterns, except mixed and evening shifts, were associated with a heightened risk of the disease compared with those working normal office hours."

Almost all the shift patterns, excluding mixed and evening shifts, were linked to increased risk of diabetes. Rotating shifts, in which people work different parts of the 24 hour cycle on a regular basis, was associated with a 42 percent higher risk.

"Rotating shifts make it harder for people to adjust to a regular sleep-wake cycle, and some research has suggested that a lack of sleep, or poor quality sleep, may prompt or worsen insulin resistance," said the authors.

The finding was published in Occupational & Environmental medicine.