The inverse relationship between caffeine and rosacea added up to a 24% lower risk for the highest quintile of consumption compared with the lowest (P<0.001 for trend), reported Suyun Li, PhD, of Brown University in Providence, and colleagues in JAMA Dermatology.

This significant inverse relationship was seen between risk of incident rosacea and increased caffeinated coffee consumption (P<0.001 for trend). Four or more servings of caffeinated coffee had a hazard ratio for rosacea of 0.77 (95% CI. 0.69-0.87) compared with less than one serving per month, whereas the relationship was not significant for decaffeinated coffee (HR 0.80, 95% CI 0.56-1.14; P=0.39 for trend).

Previous reports have had mixed results, with some even finding increased risk of rosacea with caffeine or coffee intake, commented Noelani González, MD, of Mount Sinai West in New York City, who was not involved in the study.

While rosacea patients are usually advised to avoid hot beverages (coffee, tea), sun exposure, spicy foods, and other things considered triggers, Li’s “study makes us question what we’ve been telling patients for years, and the fact that we might not need to include caffeinated coffee in that list anymore,” González told MedPage Today.

Beyond not avoiding coffee, “it offers all of us one more reason to continue drinking coffee regularly,” Mackenzie Wehner, MD, MPhil, of the University of Pennsylvania in Philadelphia and Eleni Linos, MD, MPH, DrPH, of the University of California San Francisco wrote in an accompanying editorial.

To overcome the limitations of prior studies, which had not distinguished between caffeinated beverages and seldom between amounts of caffeine and coffee consumed, Li and colleagues evaluated over 82,737 women in the Nurses’ Health Study II (mean age 50.5).

During more than 1.1 million person-years of follow-up, there were 4,945 incident cases of rosacea.

The data showed the following inverse relationship between increased caffeine intake and risk of rosacea in comparison with the lowest intake quintile of 46 mg of caffeine intake per day or less:

• 47-133 mg/d: HR 0.91 (95% CI 0.84-1.00)
• 134-233 mg/d: HR 0.92 (95% CI 0.84-1.00)
• 234-410 mg/d: HR 0.85 (95% CI 0.77-0.93)
• ≥ 411 mg/d: HR 0.76 (95% CI 0.69-0.84)

Tea and soda were not significantly related to risk of rosacea, but the findings indicated that chocolate is a potential risk factor of rosacea (P=0.04 for trend).

“Since caffeine is a known vasoconstrictor that could potentially decrease flushing and redness and has antioxidant properties, one might think that any caffeinated food would show this trend,” González commented in an interview with MedPage Today.

But she pointed to a potential issue with power to detect an association for chocolate, noting “the absolute higher intake of caffeine from coffee in comparison to other sources of food. People drink multiple cups of coffee a day, but usually don’t eat three to four chocolate bars a day!”

The researchers additionally noted the low caffeine content in chocolate, such that “other compounds may be responsible for the observed association.”

The researchers noted that an “alternative explanation is that coffee may contain other compounds that lower the risk of rosacea. However, since no association was found with decaffeinated coffee consumption, caffeine is the putative component of coffee responsible for the inverse association between coffee and risk of rosacea.”

“Further studies are required to explain the underlying mechanisms of observed associations and to explore the relationship of caffeine with rosacea subtypes,” Li and coauthors concluded.

• Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner