RESUMEN
FUNDAMENTOS: Estudos epidemiológicos têm demonstrado relação significativa entre nevos melanocíticos e melanoma cutâneo. OBJETIVO: Acompanhar o desenvolvimento de nevos melanocíticos nos alunos de uma escola composta, majoritariamente, por descendentes de holandeses e a influência do meio ambiente sobre esses indivíduos com características fenotípicas semelhantes às de seus antepassados. MÉTODOS: Em 1999, iniciou-se estudo coorte para contagem de nevos melanocíticos nos 282 alunos entre três e 17 anos, sendo 53,9 por cento meninos. Após cinco anos, realizou-se novo exame em 148 alunos entre oito e 22 anos, dos quais 49,3 por cento eram meninos. Analisou-se a relação da idade, sexo, fotótipo, cor dos olhos, cor dos cabelos e etnia dos alunos e dos pais com a presença de nevos melanocíticos no início e no final do estudo. RESULTADOS: Houve aumento significativo de nevos melanocíticos e nevos displásicos no reexame. Os meninos tiveram mais nevos melanocíticos (áreas cobertas e expostas) do que as meninas. A análise de probabilidade para razão de risco revelou que os meninos têm mais chance de desenvolver nevos melanocíticos do que as meninas, assim como os de etnia não miscigenada e miscigenada e com cabelos claros têm mais que os alunos de outras etnias e com cabelos escuros. Os que apresentam fotótipo I são mais propensos a desenvolver nevos melanocíticos nas áreas cobertas do que os que têm fotótipos II e III. CONCLUSÕES: Os dados demonstram que os indivíduos de etnia holandesa tiveram maior probabilidade de desenvolver nevos melanocíticos do que os outros grupos étnicos.
BACKGROUNDS: Epidemiological studies have shown a significant relationship between melanocytic nevi and cutaneous melanoma. OBJECTIVE: To evaluate the development of melanocytic nevi in the pupils of a school composed primarily of children of Dutch descent and to assess the effect of environmental factors on these individuals whose phenotypic characteristics were similar to those of their ancestors. METHODS: In 1999 a cohort study was initiated to count the number of melanocytic nevi in 282 pupils of 3 to 17 years of age, 53.9 percent of whom were boys. Five years later a repeat exam was conducted in 148 students of 8 to 22 years of age, 49.3 percent of whom were males. The association between the age, skin phototype, eye color, hair color and ethnic group of the pupils and their parents and the presence of melanocytic nevi was analyzed at the beginning and at the end of the study. RESULTS: There was a significant increase in cases of melanocytic nevi and dysplastic nevi at the follow-up examination. The number of melanocytic nevi was greater in boys than in girls in both covered and exposed areas of skin. Likelihood analysis calculated using the odds ratio showed that boys were more likely to develop melanocytic nevi than girls and that the children of non-mixed and mixed race with lighter hair were more likely to develop melanocytic nevi than those of other ethnic groups and those with dark hair. Children with skin phototype I were more likely to develop melanocytic nevi in covered areas of skin compared to those with skin types II or III. CONCLUSIONS: These data show that individuals of Dutch descent were more likely to develop melanocytic nevi than individuals of other ethnic origins.