%0 Journal Article
%T Indoor radon exposure and lung cancer risk: a meta-analysis of case-control studies
%A Carmine Garzillo
%A Filomena Loffredo
%A Maria Quarto
%A Mariagabriella Pugliese
%J SCIE-indexed Journal
%D 2017
%R 10.21037/13969
%X 222Rn is a naturally occurring radioactive noble gas produced by the decay of 226Ra and belonging to the decay series of 238U. Since uranium is present in the earth¡¯s crust, radon is found everywhere in different amounts depending on geology, in rocks, soil and underground water (1,2). It is formed underground, and its fraction rapidly penetrates into the outdoor atmosphere where it is quickly diluted. On the contrary, in confined spaces such as homes and office buildings, radon can accumulate to harmful levels (3). Today, radon in buildings is considered to be the most important indoor air pollutant. Moreover, radon and its products decay are the major source of ionizing radiation of natural origin for general population and it is considered a risk factor for lung cancer if inhaled in high concentration for a long period (4-6). After inhalation, radon is almost completely exhaled due to its long half-life (3.82 d) it is an inert gas while its progenies, in particular its daughters with short half-life 218Po and 214Po, are electrically charged so they can be attached to dust or smoke particles in indoor air. Once inhaled these particles migrate to lungs where, decaying, they irradiate the tissue damaging cells increasing the probability to get a lung cancer (7,8). The fraction of lung cancer attributable to radon indoor is estimated to be between 3% and 14% depending on the average radon concentration in the concerned country and the calculation methods (8). To better understand the mechanisms of the effects of ionizing radiation on humans, the World Health Organization recommend study in vitro on lymphocytes to estimate the frequency and spectrum of chromosomal aberrations as of the effects of exposure to ionizing radiation (9). Druzhinin et al. (10) conducted a study to assess the effect of exposure to radon by evaluating the frequency and type of chromosomal aberrations differences between groups of not exposed and exposed children to a radon concentration of 468¡À77 Bq/m3 during the years of investigations. The results show a significant increase of the frequencies of single and double fragmentations, chromosome interchanges, number of aberrations chromatid and chromosome type in the exposed group. Worldwide, many epidemiological studies have been carried out to estimate the association between radon exposure in houses and lung cancer for general population. However, the association between residential radon and lung cancer risk is still inconclusive. To summarize the results three meta-analyses were performed by Lubin and Boice (11), Pavia et al.
%U http://tcr.amegroups.com/article/view/13969/html