Avaliação da associação entre a favorabilidade de urânio e a mortalidade por câncer de pulmão nos municípios brasileiros no período de 2010-2020: um estudo ecológico

Abstract

Mortality due to neoplasms is usually the second leading cause of death in Brazil, being lung cancer the leading cause. For this pathology, radon is the main risk factor among non-smokers. This is a natural radioactive gas, responsible for more than 50% of the environmental ionizing radiation received by humans, ubiquitous in the atmosphere and derived from the radioactive decay of uranium-238, for which Brazil estimates to be the seventh largest holder worldwide. Aims: Primarily, to assess whether there is an association between uranium favorability and lung cancer mortality in Brazilian municipalities between 2010-2020. Secondarily, to appreciate the correlation between the types of tobacco exposure (smoking, former smoking, and passive smoking) and deaths from lung neoplasm in Brazilian states in the year 2019 and the period of 2010-2020, respectively, to employ it as a comparative. Methodology: This is an ecological study grounded in secondary data from Brazilian cities and federation units regarding uranium favorability, lung cancer mortality and types of smoking exposure. In this context, these variables were analyzed primarily employing the Kruskal-Wallis, Jonckheere-Terpstra, and Spearman correlation coefficient tests, given the purposes of the study and the assumptions required for parametric tests. Results: There were 5,582 municipalities and 27 states (including the federal district). Therefore, the Kruskal-Wallis test determined that uranium favorability, according to its classification and in a statistically significant way, was associated with other deaths from lung neoplasia in Brazilian municipalities in the period 2010-2020, H(7) = 280.960, p = 0.000. As well as, the Jonckheere-Terpstra test ensured a descending order of magnitude in the median rankings of uranium favorability in a statistically significant manner, J = 3,240,319.000, z = - 15.303, p = 0.000. As also, Spearman's correlation coefficient stated that uranium favorability and lung cancer mortality in Brazilian cities in the period 2010-2020 covary in an inversely proportional and statistically significant means; and calculated an effect size between small and medium, rs = -0.203, p < 0.001. Furthermore, Spearman's correlation coefficient also stated that smoking and deaths from lung neoplasm in the units of the federation in the year 2019 and the period 2010-2020, in that order, covaried in a directly proportional and statistically significant way; and projects an effect size large, rs = 0.665, p < 0.001. Additionally, the tests for ex-smoking and passive smoking did not achieve statistical significance. Conclusion: Uranium favorability, according to its classification and in a statistically significant manner, was associated with different lung cancer mortalities in Brazilian municipalities in the period 2010-2020, in agreement with a descending order of magnitude, covarying inversely proportionally and with an effect size between small and medium, approximately one-third of that estimated for smoking.