Results from a prospective cohort study of 82,539 women in the US found there was no increased risk for psoriasis incidence among women who consumed coffee and caffeine.
The study was conducted from 1991 to 2005. Participants were required to be free of psoriasis when the study began; at the conclusion participants were assessed for psoriasis using the Psoriasis Screening Tool questionnaire.
In the study’s final year, participants reported their caffeine consumption for 1991, 1995, 1999, and 2003, and their cumulative averages were tallied.
Investigators said in more than 1.1 million person-years of follow-up, 986 women were identified with having psoriasis.
Although the study results indicated an elevated risk for psoriasis in older women who consumed more caffeine, this risk was eliminated when their smoking was taken into account. Women who consumed a higher amount of caffeine also tended to be smokers and to drink more alcohol.
“ … we did not observe a material change of psoriasis incidence associated with coffee or caffeine intake,” researchers wrote, “after adjusting for known confounders [smoking]. Further studies are warranted to confirm our findings.”
Disclosure: See the study for a full list of relevant disclosures.