A man's risk of developing diabetes is doubled by anxiety and a lack of sleep, research suggests.
A range of symptoms linked to psychological distress contributes to a higher risk of type 2 diabetes, a study found.
Researchers followed 2,127 middle-aged men in Sweden for eight to 10 years. By the end of the study, 245 men had prediabetes, which indicated they were at risk of developing full blown type 2 diabetes.
Another 103 men had developed type 2 diabetes in full.
Researchers found that those men who reported the highest levels of distress at the start and end of the study were 2.2 times more likely to develop type 2 than those with the lowest levels.
A total of 3,100 women were also followed but their risk of developing type 2 was not linked to high levels of psychological distress.
The study, published in the journal Diabetic Medicine, was carried out by experts from the Karolinska Institute in Stockholm.
Study leader professor Anders Ekbom said: "Genetic and environmental factors are involved in the development of type 2 diabetes.
"We already knew that psychological distress and depression are risk factors for heart disease and suspected they may play a part in developing type 2 diabetes, which is corroborated by this research.