[Will the climate change affect the mortality from prostate cancer?].

Unlabelled: The global heating of the atmosphere, as well as the increase of the exposition to sunlight, will be associated with a decrease of the mortality from prostate cancer, due to an increase of the plasmatic levels of vitamin D.

Objectives: To evaluate if climatological factors (temperature, rainfall, and number of sunlight hours per year) may influence the mortality associated with prostate cancer over a five-year period.

Methods: In this ecology type study we will evaluate the trends of prostate tumors associated mortality in the period between January 1st 1998 and December 31st 2002, in the geographic area of Spain (17 Autonomic communities-CA-and 2 Autonomic cities- Ceuta and Melilla-, 43 million inhabitants). Demographic and mortality data were obtained from the National Institute of Statistics (INE) and climatological data about temperature and rainfall were obtained from the National Institute of Meteorology (INM). The provinces were classified using the climatic index of Martonne (defined as the quotient between annual rainfall and mean annual temperature plus 10). Areas with a quotient below 5 ml/m2/o C are considered extremely arid zones; between 5 and 15 ml/m2/o C are considered arid zones, between 15 and 20 ml/m2/o C semiarid zones; between 20 and 30 ml/m2/o C subhumid zones; between 30 and 60 ml/m2/o C humid zones; and over 60 ml/m2/o C superhumid zones. We compared mortality rates between different climatic areas using the Jonckheere-Terpstra test for six independent samples following the index of Martonne. All calculations were performed using the SPSS v 13.0 for Windows software. A logistic regression model was performed to identify climate factors associated with prostate cancer mortality. A likeliness of the null hypotheses inferior to 0.05 was considered significant.

Results: Prostate cancer mortality presented statistically significant differences, being higher in provinces with higher Martonne index (p < 0.001) and lower in areas with a greater number of sunlight hours per year (p = 0.041). The adjusted mortality rate associated with extreme aridity regions and was 21.51 cases/100,000 males year, whereas in humid zones it was 35.87 cases/100,000 males years.

Conclusions: Mortality associated with prostate cancer is significantly superior in regions with less exposition to the sunlight. The climate change may lead to a modification of the main epidemiologic patterns, and it may be associated with a modification of cancer mortality rates. Nevertheless, these results should be taken with caution and should be confirmed by prospective studies.