An association may exist between patients diagnosed with psoriasis and a higher frequency of indoor tanning use during one’s lifetime, according to a study data published in the British Journal of Dermatology.
In the study, investigators evaluated the frequency of indoor tanning in women with psoriasis using data acquired from the Nurses’ Health Study II. In this 2005 study, women responded to queries regarding tanning bed use frequency in high school or college, between ages 25 and 35, or during the past 2 years. Respondents indicated number of times per year they used indoor tanning, ranging from none to more than 24 times.
The cumulative average frequency was calculated across 3 periods during a single lifetime. The study included 80,923 participants, of whom 32.4% reported using indoor tanning at least once every year. Another 13.38% and 1.7% of participants reported indoor tanning usage of 3 to 11 times and ≥12 times per year, respectively. Only 2.3% of participants developed psoriasis in a follow-up analysis.
Study investigators ran a multivariable regression analysis to determine odds ratios (OR) and 95% CIs based on the “association between average indoor tanning frequency and having a psoriasis diagnosis.” When compared with women who did not tan indoors, the adjusted OR of having a psoriasis diagnosis was 1.16 (95% CI, 1.02-1.32), 1.23 (95% CI, 1.08-1.41), and 1.63 (95% CI, 1.20-2.21) for women who tanned indoors 1 to 2 times per year, 3 to 11 times per year, and ≥12 times per year, respectively (P <.0001). A significant positive correlation between the 2 factors was observed.
One major limitation of the study was the exclusion of men in the cohort. Another limitation was identified in the protocol, which did not specify the type of psoriasis nor the treatment received by patients. Researchers suggested that a potential recall bias was overlooked.
The researchers concluded that “a significant association between lifetime indoor tanning frequency and a psoriasis diagnosis” exists. They attribute the positive association to factors such as psoriasis being linked to addictive behaviors and evidence that indoor tanning can serve as a recreational activity. Indoor tanning can be regarded as a public health threat as commercial tanning beds exhibit carcinogenic effects on the skin. Considering the lack of evidence validating the effectiveness of indoor tanning on relieving psoriasis symptoms, clinicians are advised against prescribing “non-medical indoor tanning for psoriasis treatment.”
Disclosure: Multiple authors declared associations with the pharmaceutical industry. Please see original reference for a full list of authors’ disclosures.
Choong CK, Merola JF, Han J, Li X. Indoor tanning use is associated with psoriasis from the Nurses’ Health Study II [published online February 20, 2020]. Brit J Dermatol. doi: 10.1111/bjd. 18963