A new review of more than two dozen studies adds support to the link between the chronic skin disease psoriasis and diabetes.

In studies from the United States, Europe, the Middle East and elsewhere, participants with psoriasis had anywhere from an equal risk to an almost four-fold higher risk of developing diabetes than those without the skin condition.

According to the National Institutes of Health, more than three percent of adults in the U.S. have psoriasis, which is characterized by itchy, painful plaques on the skin.

Research has suggested psoriasis is tied to a higher chance of having heart disease or suffering a heart attack or stroke. One study of more than 500,000 people in the UK, released in June, also linked severe psoriasis with a 46 percent increased risk of diabetes.

Still, people with psoriasis may not know about those risks and the importance of staying on top of their heart health, according to Dr. Jashin Wu, who has studied the link between psoriasis and other diseases at Kaiser Permanente Los Angeles Medical Center.

"They should get regular checks by their primary care doctor for high blood pressure, high cholesterol (and) diabetes - all those things are very important," Wu, who wasn't involved in the new analysis, told Reuters Health.

For the review, Dr. April Armstrong from the University of California, Davis and her colleagues combined the results of 27 past observational studies and found people with psoriasis were 59 percent more likely to have diabetes than "control" participants. In particular, those with severe psoriasis were almost twice as likely to also have the blood sugar disorder.

And among five studies that tracked diabetes-free people over time, those with psoriasis were 27 percent more likely to develop it than study participants without psoriasis, the researchers reported this week in the Archives of Dermatology.

Some researchers believe the chronic, body-wide inflammation behind psoriasis may also be responsible for increasing a person's risk of diabetes, as well as heart disease and stroke. But how exactly that works still isn't clear, Wu said.

In addition, people with psoriasis tend to be heavier, more depressed and less physically active, on average, than those without the condition, which could add to their underlying diabetes risk.

According to the Centers for Disease Control and Prevention, about eight percent of the U.S. population has diabetes - a number that has increased in recent years along with obesity rates.

Armstrong and her colleagues said their results "support a robust association between psoriasis and diabetes," and they recommended extra diabetes screening and education regarding those risks for people with the skin condition.