BMI independently linked to development of psoriasis: Study

Psoriasis is a very common chronic skin disorder. It is characterized by red, itchy, scaly patches, occurring mostly on the knees, elbows, trunk, and scalp. It tends to flare up in intervals, followed by a remission. The incidence of psoriasis has been associated with obesity in various past studies. However, the influence of body mass index (BMI), which can be defined as the body mass (in kg) divided by the square of the body height (in meters), on the incidence of psoriasis has not been extensively studied.

A study was conducted by a group of researchers from the United States of America, to compare the occurrence of psoriasis among patients categorized by various BMI interpretations namely: normal or underweight, overweight, obese class 1, obese class 2/3.

They did a retrospective cohort evaluation of a demographically heterogeneous population of over 1.5 million patients in the United States of America between January 1, 2008, to September 9, 2019.

The researchers found that:

· Crude incidence of psoriasis per 10,000 person-years was directly proportional to the BMI class: obese class 2/3 (17.4%); obese class 1 (14.2%); overweight (11.9%); normal or underweight (9.5%). Thus, the crude incidence of psoriasis per 10,000 person-years was highest in the obese class 2/3 and lowest in the normal or underweight.

· Also, as compared to patients with BMI less than 25.0, those who were either overweight, obese class 1, or obese class 2/3 showed significantly greater risks for developing psoriasis.

Thus, the researchers concluded that body mass index (BMI) directly and independently regulates the occurrence of psoriasis. Also, there seems to be a graded linkage between BMI and the risk of psoriasis.

Reference:

A study titled, "Risk of psoriasis according to body mass index: A retrospective cohort analysis" by Norden A published in the JAAD journal.

DOI:https://doi.org/10.1016/j.jaad.2021.06.012