Obesity has frequently been dubbed an epidemic in the United States and is credited with causing or contributing to a wide variety of other chronic ailments, including cardiovascular disease and osteoarthritis. However, it’s also a frequent comorbidity for another common set of connected conditions — psoriasis and psoriatic arthritis.
According to 2015-2016 Centers for Disease Control and Prevention statistics, obesity impacts approximately 93.3 million American adults. And, even though the exact incidence among individuals with psoriatic disease isn’t known, data shows obesity is prevalent in this patient population.
Despite its frequent occurrence, questions still exist about the role obesity plays in contributing to psoriatic disease and its severity. There’s also been growing discussion around whether weight loss and management can be an effective therapeutic avenue.
At a minimum, many industry experts agree addressing obesity can be a vital arrow in the quiver for treating psoriatic disease.
“Obesity is a very common comorbidity of psoriasis and psoriatic arthritis,” says Mark Lebwohl, M.D., dermatology professor at Icahn School of Medicine at Mount Sinai. “It has a negative impact on the response to therapies so that many therapies don’t work as well.”
In fact, he says, existing research and clinical care interventions have shown patients who lose weight do respond better to psoriasis treatment.
The impact of obesity
Obesity is known to cause low-grade inflammation. Fat cells produce pro-inflammatory mediators, such as tumor necrosis factor-α or interleukin 6, which can contribute to the inflammation associated with psoriasis and psoriatic arthritis.
“What we do know is that our adipose tissue — or fat — is not inert. The latest research has shown it’s actually endocrinologically active,” says April Armstrong, M.D., MPH, associate dean of clinical research at Keck School of Medicine at the University of Southern California, Los Angeles. “There are certain types of adipokines or cytokines that are fat cells that actually help perpetuate the level of inflammation. They secrete a number of substances that make inflammation worse in our patients with psoriasis.”
Overall, she says, it’s clear obesity contributes to the exacerbation of psoriasis even if there’s a lack of clarity around whether it directly contributes to the development of the condition.
There is a growing body of evidence, however, that does point to a causal relationship. A study published in Therapeutic Advances in Musculoskeletal Disease revealed the incidence of psoriatic arthritis grew with an increasing body mass index.1 Additionally, an Annals of the Rheumatic Diseases study produced similar results. According to the study findings, after age 18 psoriatic arthritis risk jumps 10% for every 10-pound weight gain.2 This impact points to a need for discussing the relationship between weight and psoriasis with young patients as soon as possible.
Drs. Lebwohl and Armstrong report no relevant disclosures.
1. Nikiphorou E, Fragoulis GE. Inflammation, obesity and rheumatic disease: common mechanistic links. A narrative review. Ther Adv Musculoskelet Dis. 2018;10(8):157-167.
2. Li W, Han J, Qureshi AA. Obesity and risk of incident psoriatic arthritis in US women. Ann Rheum Dis. 2012;71(8):1267-72.
3. Klingberg E, Bilberg A, Björkman S, et al. Weight loss improves disease activity in patients with psoriatic arthritis and obesity: an interventional study. Arthritis Res Ther. 2019;21(1):17.
4. Mahil SK, Mcsweeney SM, Kloczko E, Mcgowan B, Barker JN, Smith CH. Does weight loss reduce the severity and incidence of psoriasis or psoriatic arthritis? A Critically Appraised Topic. Br J Dermatol. 2019;