European ancestry and cutaneous melanoma in Southern Brazil.
BACKGROUND
Similar to other countries, incidence and mortality rates for cutaneous melanoma (CM) are increasing in Brazil. Resulting from centuries of ethnic mixture, the skin of the Brazilian population presents all phototypes, being progressively lighter following the increase of the latitude toward the South, where the highest incidence of melanoma is observed. Studies from the United States and Argentina in whites suggest that European ancestry could represent an important risk factor for CM in those regions.


METHODS
Questionnaires from a case-control study involving 119 melanoma patients and 177 controls were reviewed for age, gender, phototype, sun exposure, photoprotection and ancestry. The patients reported the countries of ancestry of their grandparents. Data were tabulated and converted into scores that would reflect the proportion of ancestry for each country in individuals.


RESULTS
Patients with German and Italian ancestry presented higher risk for CM [odds ratio (OR), 3.5; 95% confidence interval (95% CI), 1.8-6.7 and OR, 9.7; 95% CI, 3.9-24.2, respectively]. Conversely, Brazilian indigenous ancestry showed a protective effect for the development of the disease, with an OR of 0.16 (95% CI, 0.04-0.7).


CONCLUSIONS
Some European ancestries, especially German and Italian, seem to be associated to a higher risk of CM in this sample from Southern Brazil. On the other hand, Brazilian indigenous ancestry presented as a protection factor against developing the tumour.
Bakos
L
L
Departments of Dermatology and Epidemiology and Biostatistics, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. lbakos@portweb.com.br
Masiero
N C M S
NC
Bakos
R M
RM
Burttet
R M
RM
Wagner
M B
MB
Benzano
D
D
D000328:Adult; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000453:epidemiology*; D008875:Middle Aged; D012878:Skin Neoplasms / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D044465:White People