People with the chronic skin condition psoriasis may be more likely to develop type 2 diabetes as well, according to an extensive new study.
Researchers found this was especially true in those with severe psoriasis, who were 46pc more likely to get a diabetes diagnosis than people without the condition.
Psoriasis is characterised by itchy, painful plaques on the skin. Previous studies have suggested the condition is tied to a higher chance of having heart disease, or suffering a heart attack or stroke, while other reports have hinted at a link between psoriasis and diabetes as well.
"We already knew that some of the risk factors for psoriasis and diabetes are similar, like weight," said Dr Rahat Azfar, at the University of Pennsylvania in the US. "We do think that psoriasis itself makes people at higher risk."
For the study, Dr Azfar and her colleagues consulted five years' worth of electronic medical records from about 108,000 adults with psoriasis, and about 400,000 without. None of them had diabetes at the outset.
They found 3.7pc of those with psoriasis were diagnosed with diabetes over the course of the study, compared with 3.4pc of the comparison group.
When patients' age, weight and high blood pressure were accounted for, psoriasis was still tied to a higher chance of developing diabetes, especially among the 6,200 people with severe psoriasis. In that group, 6.3pc had diabetes.
According to the study team, the body-wide inflammation that is seen both in people with psoriasis and type 2 diabetes may explain the link between the two conditions. Dr Azfar said psoriasis may induce that chronic inflammation through changes in the bloodstream, thus upping the risk of diabetes.
So far, the data cannot prove that psoriasis directly causes diabetes. And there have not been any studies to show definitively whether the ointments, pills or injections used to treat psoriasis affect a patient's chance of getting diabetes.