Risk factors for basal cell carcinoma: Case-control study

Abstract

Background: Basal-cell carcinoma (BCC) is the most common type of cancer in white population. The aim of this study was to assess risk factors for BCC. Methods: Case-control study was performed in Belgrade, Yugoslavia, from February to November 1996. By the use of a questionnaire, data on suspected risk factors were obtained from one hundred BCC cases and the same number of controls, individually matched by year of birth, sex and place of residence. For statistical analysis, t test, univariate and multivariate logistic regression were used. Results: According to conditional logistic regression analysis the following factors were related to BCC: blue eyes (Odds ratio - OR=5.95, 95% confidence interval - CI = 1.10-32.13), freckling (OR = 1.08 95% CI = 0.49-2.37), sunburns (OR = 20.83 95% CI = 2.49-174.38), farming (OR = 3.04 95% CI = 0.99-9.30), outdoor sports and recreation (OR = 9.09 95% CI = 0.97-84.90), radiotherapy (OR = 6.27 95% CI = 0.99-39.65), smoking (OR = 4.79 95% CI = 1.33-17.28) and family history of any malignant tumor (OR = 6.89 95% CI = 1.27-37.21). A significantly increased risk for BCC was also seen in sun-sensitive subjects whose skin tended to burn rather than tan in the sun (OR = 3.02 95% CI = 1.24-7.34). Acne vulgaris were inversely related to BCC (OR = 0.28 95% CI = 0.09-0.83). Conclusion: Pigmentary traits and sun sensitivity of the skin confirmed their role in the occurrence of BCC. Among environmental factors sunlight exposure, radiotherapy and smoking were independent risk factors for this malignant tumor. Acne vulgaris had a protective effect on BCC.