RISK-FACTORS FOR BASAL-CELL CARCINOMA - A CASE-CONTROL STUDY

A controlled trial was performed with the purpose of investigating whi ch factors could be considered of significant risk for the development of basal cell carcinoma. A total of 259 cases of basal cell carcinoma diagnosed from July 1991 to July 1992 were compared with 518 controls matched for age and sex. All subjects in both groups were white. Prot ocol data were submitted to statistical analysis by the chi-square tes t and by multiple conditional logistic regression analysis and the fol lowing conclusions were reached: 1) lightskin color (types I and II of the Fitzpatrick classification), odds ratio of 2.8; outdoor work unde r constant sunlight, odds ratio of 5.0; the presence of actinic lesion s due to exposure to the sun, odds ratio of 4.9, are risk factors per se. 2) Type III skin in the Fitzpatrick classification only represents a risk factor when the patient reports a history of intense sunburns, but not in the absence of such a history. 3) Sunburns per se do not r epresent a risk factor althorig the point made in item 2 of these conc lusions is valid. 4) Other suspected risk factors whose significance w as not confirmed by multiple conditioned logistic regression analysis were: residence in rural areas, light eyes and blond hair color, exten t of the awareness of the ''sun x skin cancer'' relationship, familial occurrence Of skin cancer, excessive exposure to the sun, and freckle s appearing in childhood.