Higher BMI Increases Psoriasis Risk

April 27, 2019

Higher body mass index (BMI) leads to an increased risk of psoriasis, according to a study published in PLOS Medicine.

“Higher BMI may contribute to increased inflammation of the skin, which can exacerbate psoriasis, but it could also be that psoriasis leads to a person being less physically active and thus gaining weight,” explained Mari Løset, MD, Norwegian University of Science and Technology, Trondheim, Norway.

For the study, Ashley Budu-Aggrey, PhD, University of Bristol, Bristol, United Kingdom, and colleagues identified 56 studies reporting data on the relationship between psoriasis and BMI, obesity, or being overweight. The researchers performed meta-analysis on 35 studies that compared mean BMI with psoriasis cases and controls.

The researchers found that greater BMI increased the chance of getting psoriasis.

In adults, there was a mean difference in BMI of 1.26 kg/m2 (95% confidence interval [CI], 1.02-1.51) between patients with psoriasis and controls, while a 1.55 kg/m2 mean difference (95% CI, 1.13-1.98) was observed in children.

Overall, a 1 kg/m2 increase in BMI was associated with 4% higher odds of psoriasis.

Mendelian randomisation analyses provided evidence that higher BMI causally increases the odds of psoriasis by 9% for each higher whole number on the BMI scale.

In contrast, Mendelian randomisation estimates gave little support to a possible causal effect of psoriasis genetic risk on BMI.

However, the researchers are still uncertain about how higher BMI can lead to psoriasis.

“We still do not know enough about the mechanisms behind this connection,” said Dr. Løset. “Fatty tissue is an organ that produces hormones and inflammatory signaling molecules, which could be a contributing factor.”

So far, not much research has been done on whether weight loss can cause psoriasis to disappear in these patients, although a few clinical studies suggest the possibility.

“Psoriasis is a very complex disease and we hope to study subgroups, especially individuals with severe psoriasis,” concluded Dr. Løset. “The hypothesis is that we will be able to observe even greater links with higher weight.”

Reference: https://doi.org/10.1371/journal.pmed.1002739

SOURCE: Norwegian University of Science and Technology