People with the chronic skin condition psoriasis may be more likely to develop type 2 diabetes as well, according to a new study of the medical records of more than half a million Britons.

Researchers found that was especially true in those with severe psoriasis, who were 46 percent more likely to get a diabetes diagnosis than people without the condition, after weight and other health measures were taken into account.

According to the National Institutes of Health, more than three percent of adults in the United States have psoriasis, which is characterized by itchy, painful plaques on the skin. Studies have suggested the condition is tied to a higher chance of having heart disease or suffering a heart attack or stroke (see Reuters Health story of January 10, 2012.)

And smaller reports have hinted at a link between psoriasis and diabetes as well, researchers wrote online Monday in the Archives of Dermatology.

"We already know that some of the risk factors for psoriasis and diabetes are similar, like weight," said Dr. Rahat Azfar, the lead author on the study from the University of Pennsylvania in Philadelphia.

But with the new findings, she told Reuters Health, "We do think that psoriasis itself makes people at higher risk."

That means those with psoriasis, especially severe psoriasis, should take extra precautions to eat a healthy diet and exercise regularly to ward off diabetes, Azfar added.

Other factors

For the new study, she and her colleagues consulted five years' worth of electronic medical records from about 108,000 adults in the UK with psoriasis and another four times as many without the condition. None of them had diabetes at the outset.

The researchers found slightly more of the psoriasis group was diagnosed with diabetes over the course of the study - 3.7 percent of them, compared with 3.4 percent 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, 6.3 percent of patients were diagnosed with diabetes.

Two of the researchers disclosed financial relationships with pharmaceutical companies, including those that make diabetes and psoriasis drugs.

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. Azfar said psoriasis may induce that chronic inflammation through changes in the bloodstream, thus upping the risk of diabetes.

It could also be that people with psoriasis are more depressed or exercise less, and those help explain the difference in diabetes rates, said Dr. Robert Kirsner, a dermatologist from the University of Miami Miller School of Medicine who has studied psoriasis and blood vessel diseases but wasn't involved in the new study.

So far, the data can't prove that psoriasis directly causes diabetes.

And there haven't been any studies to show definitively whether the ointments, pills or injections that are used to treat psoriasis have any effect on a patient's chance of getting diabetes, Azfar added.

So for now, people with psoriasis should talk with their doctors about other ways to reduce their diabetes risks, she said, such as by adopting a healthier lifestyle.

Kirsner agreed.

The study "suggests that patients with psoriasis perhaps should be followed more closely and may want to adhere to a better diet and all those things to prevent diabetes," he told Reuters Health.

"The dermatologist may be the first person to see them and the person who takes care of their skin, but their care shouldn't stop there."