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Higher Prevalence Reported

Monday, August 20, 2007

The incidence of rosacea may be higher than widely believed, according to a preliminary study presented at the recent rosacea research workshop, sponsored by the National Rosacea Society (NRS) during the annual Society for Investigative Dermatology meeting. In addition, an ongoing Irish study found similar prevalence rates of subtype 2 (papulopustular) rosacea in both indoor and outdoor workers.

In the preliminary study of high-resolution digital photographs of 2,933 women aged 10 to 70 from the general population, Dr. Alexa Boer Kimball, director of the clinical unit for research trials in skin at Harvard Medical School, found a prevalence rate for rosacea of 16 percent in Caucasian women. The incidence rate is comparable to the 14 percent prevalence of rosacea in women and 6 percent in men in a frequently cited study of 809 office workers in Sweden, published in 1989. This ongoing new study found an overall rosacea incidence of nearly 10 percent in a total population that also included Hispanics, African-Americans, Asians and Indians.

"Because the Swedish study was conducted before a standard definition and classification system were developed for rosacea, we were able to use the new standards to confirm the high incidence so that researchers can have more confidence in the earlier data," Dr. Kimball said. The standard system was published by an NRS consensus committee in 2002 to unify research, provide common terminology and serve as a diagnostic reference in clinical practice.

As expected, subtype 1 (erythematotelangiectatic) rosacea, characterized by facial redness, was the most prevalent form of the disorder. It was found in 14.8 percent of the Caucasian women in the new study, compared to 1.5 percent with subtype 2 (papulopustular) rosacea, which includes bumps and pimples. The researchers studied women from Los Angeles, Rome, London and Akita, Japan. Rosacea was especially prevalent in the English group, at more than 20 percent, although the incidence of subtype 2 was somewhat higher among the American women.

"There was clearly a difference in the rate of occurrence in London, and this effect persisted even when Fitzpatrick skin type was taken into account," Dr. Kimball said. She noted that the mean age of the women in the study was 45 years old, and that incidence increased with age in those who were premenopausal but not in postmenopausal subjects.

In an ongoing NRS-funded study in Ireland, Dr. Maeve McAleer of the Regional Centre of Dermatology, Mater Misericordiae University Hospital, Dublin, noted that Subtype 2 rosacea was found present in 2.6 percent of 400 subjects from among hospital workers and 2.9 percent from Aran Island inhabitants. Of the hospital workers, 94 percent worked indoors and 40 percent reported more than 10 hours per week outdoor exposure in winter and summer, versus 53 percent indoor workers and 80 percent with more than 10 hours of outdoor exposure on the Islands.

Both populations were primarily of the fairest skin types, although the Aran Island subjects had a far greater degree of photodamage with peak scores greater than 6 for 40 percent, versus 3 percent for the hospital workers. Both rosacea groups reported high rates of flushing, with 80 percent of the hospital workers and almost 60 percent of the Aran Island subjects flushing once a week.

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