Researchers have found that people working night shifts are more likely to develop Type 2 diabetes, a precursor to cardiovascular diseases.

Type 2 diabetes is a chronic condition that affects the way the body processes blood sugar (glucose). The study found that people working irregular or rotating shifts with usual night shifts were 44 per cent more likely to have Type 2 diabetes. In addition, compared to day workers, all shift workers were more likely to have Type 2 diabetes, except for permanent night shift workers, the researchers mentioned.

"We see a dose-response relationship between frequency of night shift work and Type 2 diabetes, where the more often people do shift work, the greater their likelihood of having the disease, regardless of genetic predisposition," said Ceiine Vetter, Professor at the University of Colorado-Boulder.

"This helps us understand one piece of the puzzle: frequency of night shift work seems to be an important factor," Vetter added. For the study, published in the journal Diabetes Care, the team examined data from more than 270,000 people, including 70,000 who provided in-depth lifetime employment information and a sub-group of more than 44,000 for whom genetic data were available.

More than 6,000 people in the sample population had Type 2 diabetes. Using information on more than 100 genetic variants that are associated with Type 2 diabetes, the research team developed a genetic risk score that they used to assign a value to each participant. The results showed that those with the highest genetic risk scores were almost four times as likely to develop Type 2 diabetes compared to individuals who had lower genetic risk scores.

According to the World Health Organisation (WHO) the global prevalence of diabetes has nearly doubled since 1980, rising from 4.7 per cent to 8.5 per cent in the adult population. The majority of people with diabetes are affected by Type 2 diabetes.