Women with psoriasis run a higher risk of diabetes and high blood pressure, perhaps because of the underlying inflammation that causes the skin condition, researchers said on Monday.
Psoriasis should be considered "a systemic disorder, rather than simply a skin disease," Dr. Abrar Qureshi of Brigham and Women's Hospital and Harvard Medical School in Boston wrote in a study in the April issue of Archives of Dermatology.
They looked at data from thousands of female U.S. nurses who enrolled in a study in 1991 and have been checked periodically for numerous health-related issues.
They said 1,813 women were diagnosed with psoriasis over a 14-year period. These women were 63 percent more likely to develop diabetes and 17 percent more likely to develop hypertension than those who were psoriasis-free.
The team said inflammation can lead to high blood pressure and may also be a factor in insulin resistance, a pre-diabetic condition.
"Inflammation could be a biologically plausible mechanism" underlying the association with diabetes, the researchers said. "Psoriasis is a chronic inflammatory disease, and inflammation is a risk factor for hypertension."
The link was found regardless of their weight, age and whether they smoked. While other studies have linked psoriasis to diabetes and hypertension, factors like obesity and smoking have variously been blamed, the researchers said.
Psoriasis, a chronic inflammatory skin disease that causes itchy red plaques on the skin's surface, affects about 7.5 million people in the United States alone. In severe cases large areas of the body can be affected, and it can bring arthritis, depression and other problems.
Because the study was restricted to white women, the findings cannot be generalized to men or to other races, the researchers added.
While systemic steroid therapy for psoriasis could foster diabetes or hypertension, such treatment is not the standard for care in the United States, the researchers said. And patients often abandon steroid creams after short periods of use.