People with psoriasis are at an increased risk of developing Type-2 diabetes than those without the condition, and the risk increases dramatically based on the severity of the disease, says a study.

Psoriasis is a disease of the immune system in which inflammation causes skin cells to multiply faster than normal.They cause raised, red patches covered by silvery scales when they reach the surface of the skin and die. People with psoriasis that covers 10 per cent of their body or more are 64 per cent more likely to develop diabetes than those without the condition, the findings published in the Journal of the American Academy of Dermatology showed.The researchers estimate that applying the study's findings to the number of people who have psoriasis worldwide would equate to 125,650 new cases of diabetes attributable to psoriasis per year.

"The type of inflammation seen in psoriasis is known to promote insulin resistance, and psoriasis and diabetes share similar genetic mutations suggesting a biological basis for the connection between the two conditions we found in our study," said the study's senior author Joel Gelfand, Professor at Perelman School of Medicine at the University of Pennsylvania in the US."We know psoriasis is linked to higher rates of diabetes, but this is the first study to specifically examine how the severity of the disease affects a patient's risk," Gelfand said. 

In order to measure psoriasis severity, Gelfand and his team used body surface area (BSA), which measures the percentage of the body covered by psoriasis. Using a UK database, they surveyed general practitioners about BSA affected by psoriasis and looked at data on 8,124 adults with psoriasis and 76,599 adults without psoriasis over the course of four years.They found patients with a BSA of two percent or less had 21 per cent higher risk of developing diabetes than those without psoriasis.This risk increased dramatically in patients with a BSA of 10 per cent or more. They were 64 per cent more likely to develop diabetes than those without the condition, the study showed.