In westernized societies, acne vulgaris is a nearly universal skin disease afflicting 79% to 95% of the adolescent population. In men and women older than 25 years, 40% to 54% have some degree of facial acne, and clinical facial acne persists into middle age in 12% of women and 3% of men. Epidemiological evidence suggests that acne incidence rates are considerably lower in nonwesternized societies.
Acne affects between 40 million and 50 million individuals in the United States. Although acne mainly affects adolescents, it is also present in children and adults. One study found some degree of facial acne in 54% of women and 40% of men older than 25 years.2 In this same group, clinical facial acne affected 12% of the women and 3% of the men and persisted into middle age. Cunliffe and Gould reported similar results 20 years earlier. In pediatric populations, the prevalence of acne increases with age. In 10- to 12-year-old children, 28% to 61% of the population has clinically diagnosed acne, whereas 79% to 95% of 16- to 18-year-old adolescents are affected. Even a significant percentage of children (aged 4-7 years) are diagnosed with acne. Thus in the Western world, acne is a ubiquitous skin disease affecting primarily adolescents but also a significant portion of adults older than 25 years.
Few studies have evaluated the prevalence of acne in nonwesternized societies. However, there is suggestive evidence in nonindustrialized societies that the incidence of acne is lower than in westernized populations. Schaefer, a general practitioner who spent almost 30 years treating Inuit (Eskimo) people as they made the transition to modern life, reported that acne was absent in the Inuit population when they were living and eating in their traditional manner, but upon acculturation, acne prevalence became similar to that in Western societies.
Prior to World War II, Okinawa was an isolated island outpost in the South China Sea, and its native inhabitants lived a rural life with few or none of the trappings of industrialized societies. Extensive medical questionnaires by US physicians administered to local physicians who had practiced from 8 to 41 years revealed that, "These people had no acne vulgaris." Dermatological examination of 9955 schoolchildren (aged 6-16 years) conducted in a rural region in Brazil found that only 2.7% of this pediatric population had acne. Dermatological examination of 2214 Peruvian adolescents by pediatricians demonstrated that acne prevalence (grades 1-4) was lower (28%) in Peruvian Indians than in mestizos (43%) or whites (45%).
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