[Melanoma, altitude, and UV-B radiation]

Abstract

Background and objectives: UV radiation is the main modifiable risk factor for the development of cutaneous melanoma. Many people in the Spanish province of Granada live at high altitudes and, therefore, receive high doses of UV-B radiation. The aims of this study were to assess the possible association between melanoma and altitude and to measure the daily erythemal dose at different altitudes.

Material and methods: An epidemiological study was carried out between 1982 and 2007 to assess the relationship between altitude, daily erythemal dose, and the prevalence of melanoma. We calculated the prevalence of melanoma in patients with a clinical and histological diagnosis of melanoma at Hospital Clínico Universitario San Cecilio in Granada, Spain. All individuals were required to be residents of the province of Granada in order to be included in the study. The prevalence of melanoma was calculated for altitude intervals of 100 m. Daily erythemal dose was estimated using measures of UV-B radiation obtained with pyranometers at altitudes of 0, 680, 1200, and 3398 m above sea level during the Evaluation of the Effects of Elevation and Aerosols on UV Radiation (VELETA) 2002 field campaign.

Results: The highest prevalence of melanoma was found between 1400 and 1499 m above sea level (the interval at which the highest settlements are found), with a rate of 2.36 cases per 1000 inhabitants (95% confidence interval, 0.64-6.03). Above 700 m, the daily erythemal dose increased exponentially with increasing altitude.

Conclusions: We observed a tendency toward increased prevalence of melanoma at higher altitude, with higher prevalences observed beyond 700 m above sea level.