Studio di un modello di correlazione tra la fluttuazione del tenore di metalli pesanti e di altri fattori ambientali e la salute umana in Sardegna
Since the first half of the 20th century, the incidence of Multiple Sclerosis (MS), Type 1 Diabetes (T1D) and Autism Spectrum Disorders (ASDs) has increased in Sardinia. T1D results from autoimmune destruction of insulin, producing beta cells of the pancreas; MS is a chronic disease of the central nervous system, causing neurological affliction; Autism is defined as a complex developmental disability that generally appears during the first three years of life. Concerning MS and T1D, Sardinia island has one of the highest incidence rate in the world. In this island, there is the presence of phenotypes of these diseases, due to the homogeneous genetic background of the local population. Indeed, Sardinia population is a genetic isolate. The genetic background by itself does not explain such increasing incidence. T1D and MS increase with latitude, but Sardinia is an exception. Furthermore, mining exploitation was one of the most important economic activities in Sardinia during the past centuries and a lot of data are today available for the researchers. For this reasons Sardinia is an ideal setting to study a possible correlation between environmental factors and the diseases above, because of sardinian people genetic background and environmental peculiarities of the island. A set of environmental data and the frequency data of MS, T1D and ASD were investigated to evaluate the correlation between environmental factors and the frequency of these diseases. In particular, among the environmental factors, geochemical data are included in the Geochemical Database of the Department of Civil, Environmental Engineering and Architecture (DICAAR) of the Cagliari University. This Database is populated by thousands of data concerning soils, rocks and stream sediments. A stream-sediment-type sampling, which is widely used for mineral prospecting, has the advantage of effectively representing the overall geochemical print of a wide portion of territory such as a stream basin. Environmental and diseases data were analyzed through the statistical methods which were used by mining prospections activities. Environmental factors considered in this study are: geochemical values of each lithology, lithology and geology, sun exposure and climate. Also spatial analysis distribution of MS, T1D and ASDs was done. Therefore, a correlation between the environmental factors in reference to the total population and the frequency of the diseases was evaluated. Moreover, the correlation between the environmental factors in both male and female population and the frequency of the diseases was investigated. In a first time these relationships were investigate for each municipalities. Afterwards, 109 Homogeneous Areas (HA) from lithological point of view were identified. Each Homogeneous Area includes one or more municipalities, which have the same lithological features. Then, the relationship between the environmental factors and the frequency of diseases was evaluated for each HA. About T1D analyses, they revealed negative associations between the incidence of the disease and some elements, such as Cu (r = -0.349, Pvalue = 2*10-4) and Zn (r = -0.332, Pvalue = 4.20*10-4), while, concerning MS, a mild correlation was present between Cu (r = -0.460, Pvalue = 1*10-3) and the distribution of the disease in the male gender. A significant correlations was calculated among Pb (r = 0.478, Pvalue = 3.43*10- 6), Cd (r = 0.412, Pvalue = 8.10*10-5), Zn (r = -0.378, Pvalue = 3.3*10-4) and the presence of ASDs. In this research was used for the first time a geo-epidemiological approach to identify environmental factors involved to the geographical distribution of above diseases. Moreover, the elements significantly correlated with MS, T1D and ASDs could be markers (pathfinders) of other elements not analyzed in this study (confounding), but they could be potentially involved on the onset of the diseases. Also, our results should be considered as hypothesis-generating rather than hypothesis testing study. This kind of study is unusual and it has a deep interdisciplinary approach so the present results must be better confirmed in future studies.
economic geology, geologia medica, giacimentologia, medical geology, Settore BIO/13 - Biologia Applicata
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