A study using data collected from Danish twins found that psoriasis is associated with type 2 diabetes, body mass index and obesity. The findings also indicate a potential common genetic cause for psoriasis and obesity. The study, “Association of Psoriasis With the Risk for Type 2 Diabetes Mellitus and Obesity,” was published online in JAMA Dermatology.
Psoriasis is a common, chronic inflammatory disease that is associated with an increased risk of cardiovascular, metabolic, and renal disease in a manner that varies with the severity of psoriasis and is often independent of traditional risk factors for the other diseases.
The association of psoriasis with type 2 diabetes mellitus and obesity has been extensively studied and numerous meta-analyses have clearly associated psoriasis with both obesity and diabetes.
In the study, Ann Sophie Lønnberg, MD, with the University of Copenhagen and colleagues studied sets of Danish twins, ages 20 to 71, using a psoriasis questionnaire, diagnoses of type 2 diabetes at hospital discharge, and self-reported body mass index (BMI).
Researchers analyzed data of 33,588 twins, and found that the total prevalence of psoriasis was 4.2%, the prevalence of diabetes was 1.4%, and the average BMI was 24.5, with obesity (BMI from 30 to 34) found in 6.3% of the people examined.
Psoriasis was more prevalent in those with diabetes, 7.6% of 459 people, than in those without diabetes (4.1% of 1,370 people).
Individuals with psoriasis also had a higher BMI compared to those without the disease (25 versus 24.4), and a higher risk of obesity.
Twins with psoriasis had a higher BMI and were more likely to be obese than co-twins without the disease. The prevalence of diabetes was the same in the twins with psoriasis, compared with the co-twins without psoriasis.
Results also indicated that the relationship between psoriasis and obesity could be partly due to a common genetic cause.
“Psoriasis, type 2 diabetes mellitus and obesity are strongly associated in adults after taking key confounding factors such as sex, age and smoking into account. Results indicate a common genetic etiology of psoriasis and obesity. Conducting future studies on specific genes and epigenetic factors that cause this association is relevant,” the researchers concluded, according to a news release.
In an editorial, “Psoriasis, Type 2 Diabetes Mellitus & Obesity — Weighing the Evidence,” Joel M. Gelfand, MD, MSCE, with the University of Pennsylvania Perelman School of Medicine, wrote: “The unique twin design of the study by Lønnberg and colleagues, in which increasing BMI was associated with a diagnosis of psoriasis, allowed the investigators to identify a genetic correlation between psoriasis and BMI.”