Study Identifies Risk Factors Linked to Excessive Sun Exposure in Those with Psoriasis

New findings suggest excessive sun exposure (ESE) among patients with psoriasis is more likely among patients who are female, younger, of average weight, of intermediate skin phenotype, and who have a history of phototherapy.1

These findings resulted from a new study authored by a set of investigators, such as Emmanuel Mahé, MD, PhD, of Victor Dupouy Hospital’s dermatology department in France. The analysis was conducted to address tanning addiction, a condition thought to impact 10% to 25% of the population and lead to ESE.

Mahé and the other investigators highlighted the complexity of the link between psoriasis, therapies, and ultraviolet or sun exposure, pointing to research suggesting that sun exposure and phototherapies usually beneficially impact psoriasis but increase skin cancer risk.2

“The objectives of this study were to estimate the prevalence of excessive sun exposure (ESE) — as a proxy for tanning addiction — in patients with moderate-to-severe psoriasis and to identify the factors associated with this behavior,” Mahé and colleagues wrote.1 “In particular, the main hypothesis was that the phototherapy and sun exposure recommended as a part of the treatment for severe psoriasis could be associated with, or even induce, ESE behavior.”

The investigators drew their data from the PsoBioTeq registry, conducting their cross-sectional ancillary study with a prospective, multicenter cohort study design. The research was being carried out in France. Enrollment into the PsoBioTeq registry takes place at the beginning of a biologic or systemic treatment, the latter of which included methotrexate, apremilast, or cyclosporine.

A self-administered survey was provided to participants upon entry into the registry, with inquiries being connected to sun-related behaviors. As an example, 1 key item posed the question, “Which of the following sentences best describes your current behavior?” Among options for responses, examples included: “I try to avoid sun exposure,” “I try to expose myself to the sun as often as possible,” and “I don't mind being in the sun occasionally, but I don't particularly sunbathe.”

Those who selected the option suggesting sun exposure as often as possible were categorized by the investigative team as exhibiting elevated sun exposure, or ESE. All patients involved in the PsoBioTeq registry from July 2012 - April 2022 who had answered the sun behavior question were included in this analysis. The team would extract data related to skin phototype, demographic information, body mass index (BMI), comorbidities, smoking status, details of psoriasis severity and any history with treatments, and the existence of photo-induced lesions.

The investigators carried out their statistical analyses using R software (version 4.1.2). All of the tests were 2-sided, with statistical significance being set by the research team at a P-value of less than .05. Mahé and colleagues noted that 17.2% of the 3705 individuals who were assessed reported having higher levels of sun exposure.

The team's multivariate analysis demonstrated a variety of factors that they reported to be linked with increased likelihood of ESE: female gender (OR 1.52, 95% CI [1.20; 1.93]), younger age (OR 0.97, 95% CI [0.96; 0.97]), being of 'normal weight' (OR 0.57, 95% CI [0.42; 0.77]), having an intermediate skin phototype (OR 1.80, 95% CI [1.36; 2.38]), and previous history of receiving phototherapy (OR 1.53, 95% CI [1.19; 1.96]).

Conversely, the investigators found that prior utilization of ustekinumab therapy had an association with a lower likelihood of ESE (OR 0.40, 95% CI [0.19; 0.84]). Nevertheless, they highlighted that additional research into this finding would be necessary.

“Prior treatment with phototherapy was strongly associated with ESE behavior; however, further studies are required to determine whether phototherapy changed the sun-related behavior of these patients or whether this behavior prompted the more frequent use of phototherapy,” Mahé and colleagues concluded.1

References

1. Mahé, E., Curmin, R., Paul, C., Bachelez, H., Beylot-Barry, M., Beneton, N., Dupuy, A., Joly, P., Jullien, D., Richard, M.-.-A., Viguier, M., Sbidian, E., Chosidow, O., Tubach, F. and (2025), Sun Exposure Behaviors of Patients With Moderate-to-Severe Psoriasis: Results From the French PSOBIOTEQ Cohort. JEADV Clinical Practice. https://doi.org/10.1002/jvc2.70029.

2. R. S. Stern, L. A. Thibodeau, R. A. Kleinerman, J. A. Parrish, and T. B. Fitzpatrick, “Risk of Cutaneous Carcinoma in Patients Treated With Oral Methoxsalen Photochemotherapy for Psoriasis,” New England Journal of Medicine 300 (1979): 809–813.