Psoriasis Risks Are More Than Skin-Deep

Psoriasis linked with obesity, BMI, type 2 diabetes in Danish twin study.


If you’re familiar with psoriasis, you know that it’s more than just a rash—it’s a chronic autoimmune skin disease that can be debilitating. And now new research suggests a possible connection between psoriasis and other conditions.

According to a press release issued by The Journal of the American Medical Association Network Journals, a new study of Danish twins found a connection between psoriasis and type 2 diabetes, obesity and body mass index (BMI). The findings also suggested a possible genetic cause between psoriasis and obesity.

Psoriasis is a skin disease that speeds up the growth cycles of skin cells. According to the Centers for Disease Control and Prevention (CDC), psoriasis causes patches of thick red skin and silvery scales that mostly appear on the elbows, knees, back, scalp, face, palms and soles of feet. It is not contagious.

Psoriasis has been associated with diabetes and obesity--a connection that could be explained by genetics or by environmental factors such as drinking alcohol and smoking. By using twins for the participants, this study was able to draw a genetic correlation between psoriasis and obesity.

“Twins provide a unique natural experiment, which offers valuable information about the genetic and environmental basis of multifactorial diseases like psoriasis,” lead author Ann Sophie Lønnberg, MD, said in an interview with DailyRx.

Dr. Lønnberg is from the University of Copenhagen in Denmark.

To conduct the study, researchers looked at data from 33,588 twins who were between the ages 20 and 71. About 4.2 percent of the twins had psoriasis and 1.4 percent had diabetes. The average BMI for the group was 24.5 and 6.3 percent of the twins were obese.

Researchers found that 7.6 percent of the participants with diabetes also had psoriasis whereas only 4.1 percent of the participants without diabetes had psoriasis. Participants with psoriasis had a higher average BMI (25) than those without psoriasis (24.4).

The study also found that out of 720 twin pairs where one twin had psoriasis and the other didn’t, the twins with psoriasis averaged a higher BMI and were more likely to be obese, which suggests a genetic cause. The prevalence of diabetes was the same in twins with and without psoriasis.

Although the authors suggested that the connection between psoriasis and obesity is genetic, they said they can’t infer causation. Psoriasis could cause some people to live a more sedentary lifestyle, which could contribute to obesity and diabetes.

The full study was published online in JAMA Dermatology.

The authors reported no financial disclosures or conflicts of interest.