The Classification of Critical Periods for Melanoma Development due to UV-Radiation

Abstract

Sufficient epidemiologic evidence exists that exposure to ultraviolet light is related to the occurence of malignant melanoma. Especially intermittent intensive sunlight and sunburns are important risk factors. Elwood and Jopson (1997) presented in a meta-analysis of case-control studies an overall odds ratio (OR) of 1.91 (95%-confidence interval (CI): 1.69 - 2.17) for sunburns at all ages. Concerning the idea of a ``critical period'' for the relationship between sunburn episodes and malignant melanoma there is substantial heterogeneity in the published literature. This analysis is based on data of 603 melanoma patients and 627 population controls from 11 participating centers in seven European countries. The results confirm the increase in melanoma risk for an increasing number of sunburns during childhood and adulthood in the same magnitude of risk. The maximum OR for the highest exposure category of more then five painful and blistering sunburns during the childhood was 2.0 (95%-CI: 1.2 - 3.5) and during the adulthood 2.1 (95%-CI: 1.4 - 3.3), respectively. Thus there exists equivalent risk for both periods of life and our data do not support the presence of a ``critical period''.