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SENTIERI project (Epidemiological Study of Residents in Italian Contaminated Sites) studied mortality in the sites of national interest for environmental remediation (National Priority Contaminated Sites-NPCSs). SENTIERI described mortality of residents in NPCSSs, and it specifically focused on causes of death for which environmental exposure is suspected or ascertained to play an etiologic role. The epidemiological evidence of the causal association was classified a priori into one of these three categories: Sufficient (S), Limited (L), and Inadequate (I). Mortality in the period 1995-2002 was studied for 63 single or grouped causes at the municipal level by computing: crude rate, standardized rate, standardized mortality ratios (SMR), and SMR adjusted for an ad hoc deprivation index. Regional populations were used as references for SMR calculations and 90% CI accompanied SMR values. The deprivation index was constructed using 2001 national census variables for the following socioeconomic domains: education, unemployment, dwelling ownership, and overcrowding. SENTIERI results will allow the priorities setting in remediation intervention so as to prevent adverse health effects from environmental exposure. This paper's objective is to present the rationale, methods, advantages, and limitations underlying SENTIERI project and to describe data and resources required to apply a similar approach in other countries.

The National Environmental Remediation programme in Italy includes sites with documented contamination and associated potential health impacts (National Priority Contaminated Sites-NPCSs). SENTIERI Project, an extensive investigation of mortality in 44 NPCSs, considered the area of Taranto, a NPCS where a number of polluting sources are present. Health indicators available at municipality level were analyzed, that is, mortality (2003-2009), mortality time trend (1980-2008), and cancer incidence (2006-2007). In addition, the cohort of individuals living in the area was followed up to evaluate mortality (1998-2008) and morbidity (1998-2010) by district of residence. The results of the study consistently showed excess risks for a number of causes of death in both genders, among them: all causes, all cancers, lung cancer, and cardiovascular and respiratory diseases, both acute and chronic. An increased infant mortality was also observed from the time trends analysis. Mortality/morbidity excesses were detected in residents living in districts near the industrial area, for several disorders including cancer, cardiovascular, and respiratory diseases. These coherent findings from different epidemiological approaches corroborate the need to promptly proceed with environmental cleanup interventions. Most diseases showing an increase in Taranto NPCS have a multifactorial etiology, and preventive measures of proven efficacy (e.g., smoking cessation and cardiovascular risk reduction programs, breast cancer screening) should be planned. The study results and public health actions are to be communicated objectively and transparently so that a climate of confidence and trust between citizens and public institutions is maintained.

SENTIERI Project is the first comprehensive study of the health impact of residence in Italian polluted sites (IPSs). The present Chapter examines the main validity aspects of the present mortality investigation and the evaluation of causality of the observed associations; in addition, some recommendations for public health intervention and research priorities in epidemiological studies on environment and health are given. Exposure ascertainment is a key aspect when an ecological study design is adopted in environmental epidemiology, therefore any exposure potentially affecting the population at study should be described in detail. This is here discussed. SENTIERI is an ecological study, based on a priori hypotheses, in which each IPS's types of exposure were described with specific attention to human exposure. Though, when commenting the results, the problem of concurrent air pollution exposure and/or industrial activities implying occupational risk, if present in the IPSs, was taken into account. Socioeconomic status is a determinant of health and disease, therefore in SENTIERI the Standardized Mortality Ratios were computed both crude and adjusted for an ad hoc deprivation index. About 60% versus an expected 40% of IPSs residents are in the two most deprived quintiles of the index. This hints to a possible problem of environmental justice that should be taken into account when planning remediation intervention. The mortality results here presented are a first step in the epidemiological IPSs' characterization, and some developments have been made or planned. Firstly, a mortality analysis was performed combining mortality data in IPSs presenting similar pollution, i.e. asbestos, or industrial hazardous wastes or dumping sites; secondly, the mortality analysis will be extended beyond 2002, namely the year when ICD X started to be in use in Italy. In addition, disease prevalence will be investigated using hospital discharge records; cancer incidence and congenital anomalies incidence will be studied in IPSs in which a Cancer Register or a Congenital Anomalies Register are active. The above described activities will lead to a more valid estimate of the disease burden of IPSs residents, and allow to identify priorities of remediation activities. The method adopted in SENTIERI, specifically the ecological design and the use of mortality data at municipal level, in general does not grant the evaluation of the causal association between environmental exposure and adverse health effects. However, it allows etiological observations that make unacceptable the delay of remediation intervention.

SENTIERI Project has assessed the overall mortality profile in all the IPSs combined, and performed IPS-specific analyses. The epidemiological evidence of the causal association between cause of death and exposure was classified into one of these three categories: Sufficient (S), Limited (L) and Inadequate (I). The procedures and results of the evidence evaluation have been presented in a 2010 Supplement of Epidemiology & Prevention devoted to SENTIERI. Mortality for causes of death with a priori Sufficient or Limited evidence of association with the environmental exposure exceeds the expected figures, with a SMR of 115.8 for men (90%CI 114.4-117.2; 2 439 extra deaths) and 114.4 for women (90% CI 112.4-116.5; 1 069 extra deaths). These excesses are also observed when analysis is extended to all the causes of death (i.e. with no restriction to the ones with a priori Sufficient or Limited evidence): for a total of 403 692 deaths (men and women combined), an excess of 9 969 deaths is observed, with an average of around 1 200 extra deaths per year. Most of these excesses are observed in IPSs located in Southern and Central Italy. The distribution of the causes of deaths shows that the excesses are not evenly distributed: cancer mortality accounts for 30%of all deaths, but is 43.2%of the excess deaths (4 309 cases of 9 969). Conversely, the percentage of excesses in non cancer causes, 19%, is lower than their share of total mortality (42%). Consistently with previous studies, the results suggest that the health status of populations living in the IPSs is worse than what regional averages show. Compared to previous studies, the analysis of the causes selected in SENTIERI, on the basis of a priori Sufficient or Limited evidence of association with the environmental exposures, provides additional information on their role, though some limitations, due to methodology and data used, should be considered.

SENTIERI Project (Mortality study of residents in Italian polluted sites) studies mortality of residents in 44 sites of national interest for environmental remediation (Italian polluted sites, IPS). The epidemiological evidence of the causal association between causes of death and exposures was a priori classified into one of these three categories: Sufficient (S), Limited (L) and Inadequate (I). In these sites various environmental exposures are present. Asbestos (or asbestiform fibres as in Biancavilla) has been the motivation for defining six sites as IPSs (Balangero, Emarese, Casale Monferrato, Broni, Bari-Fibronit, Biancavilla). In five of these, increases in malignant neoplasm or pleura mortality are detected; in four of them, results are consistent in both genders. In six other sites (Pitelli, Massa Carrara, Aree del Litorale Vesuviano, Tito, "Aree industriali della Val Basento", Priolo), where other sources of environmental pollution in addition to asbestos are reported, mortality from malignant neoplasm of pleura is increased in both genders in Pitelli, Massa Carrara, Priolo, "Litorale vesuviano". In the time span 1995-2002, a total of 416 extra cases of malignant neoplasm of pleura are detected in the twelve asbestos-polluted sites. Asbestos and pleural neoplasm represent an unique case. Unlike mesothelioma, most causes of death analyzed in SENTIERI have multifactorial etiology; furthermore, in most IPSs multiple sources of different pollutants are present, sometimes concurrently with air pollution from urban areas: in these cases, drawing conclusions on the association between environmental exposures and specific health outcomes might be complicated. Notwithstanding these difficulties, in a number of cases an etiological role could be attributed to some environmental exposures. The attribution could be possible on the basis of increases observed in both genders and in different age classes, and the exclusion of a major role of occupational exposures was thus allowed. For example, a role of emissions from refineries and petrochemical plants was hypothesized for the observed increases in mortality from lung cancer and respiratory diseases in Gela and Porto Torres; a role of emissions from metal industries was suggested to explain increased mortality from respiratory diseases in Taranto and in Sulcis-Iglesiente-Guspinese. An etiological role of air pollution in the raise in congenital anomalies and perinatal disorders was suggested in Falconara Marittima, Massa-Carrara, Milazzo and Porto Torres. A causal role of heavy metals, PAH's and halogenated compounds was suspected for mortality from renal failure in Massa Carrara, Piombino, Orbetello, "Basso bacino del fiume Chienti" and Sulcis-Iglesiente-Guspinese. In Trento-Nord, Grado and Marano, and "Basso bacino del fiume Chienti" increases in neurological diseases, for which an etiological role of lead, mercury and organohalogenated solvents is possible, were reported. The increase for non-Hodgkin lymphomas in Brescia was associated with the widespread PCB pollution. Mortality for causes of death with a priori Sufficient or Limited evidence of association with the environmental exposure exceeds the expected figures, with a SMR of 115.8% for men (90% IC 114.4-117.2; 2 439 extra deaths) and 114.4% for women (90% CI 112.4-116.5; 1 069 extra deaths). These excesses are also observed when analysis is extended to all the causes of death (i.e. with no restriction to the ones with a priori Sufficient or Limited evidence): for a total of 403 692 deaths (both men and women), an excess of 9 969 deaths is observed, with an average of about 1 200 extra deaths per year. Most of these excesses are observed in IPSs located in Southern and Central Italy. The procedures and results of the evidence evaluation are presented in a 2010 Supplement of Epidemiology & Prevention devoted to SENTIERI.

SENTIERI Project (Mortality study of residents in Italian polluted sites) studied mortality of residents in the sites of national interest for environmental remediation (Italian polluted sites--IPSs). IPSs are in proximity of either active or dismissed industrial areas, near dumping sites of industrial and hazardous waste or incinerators. SENTIERI Project described and evaluated the mortality of the populations residing in IPSs and it specifically focused on causes of death for which environmental exposure is suspected or ascertained to play an etiologic role. The epidemiological evidence of the causal association was classified a priori into one of these three categories: Sufficient (S), Limited (L) and Inadequate (I). The study results will allow the priorities setting in remediation intervention, so as to prevent adverse health effects from environmental exposure. At the time of 2001 Census, about 10%of Italian population resided in the 44 IPSs included in SENTIERI; the mortality analysis was carried out for the years 1995-2002 for 63 causes of death. The study results for the 44 IPSs are here commented and read on the basis the a priori evaluation of the epidemiological evidence in terms of strength of the causal association, and taking into account the limits of a geographic study design and its implied complexities. The procedures and results of the evidence evaluation have been presented in a 2010 Supplement of Epidemiology & Prevention devoted to SENTIERI.

Objective: To investigate cause-specific mortality in a population exposed to high levels of 50 Hz magnetic fields, in a district of Rome., Design: A cohort of 357 subjects that are resident in an area of about 100 meters on the two sides of a 60 kV power line was studied. Exposure to 50 Hz magnetic fields was evaluated by spot and long-term measurements and by adopting a model based on current load, characteristics of the line and distance of dwellings from conductors. The mortality experience of the cohort was observed from January 1st, 1980 through December 31st, 2003. Analysis took into account duration of residence and latency. Separate analyses were performed for three subcohorts characterized by different distances from the line and different estimated and measured field levels., Main Outcomes: Cause-specific standardized mortality ratios (SMRs) were computed comparing the observed number of deaths with the corresponding expected figures derived from the Latium Region mortality rates. This was done both in the overall cohort and in the subcohorts., Results: All-causes mortality of the cohort did not differ from expected values (SMR 0.99; 95% CI 0.73-1.35; 40 observed). All cancers mortality showed a non-significant increase (SMR 1.34; 95% CI 0.82-2.18; 16 observed), that reached statistical significance in the analyses limited to subjects with more than 30 years of residence (SMR 2.09; 95% CI 1.05-4.19; 8 observed). Mortality from lymphohaematopoietic malignancies was increased, based on two cases of leukemia. All cancers mortality was highest in the subcohort closest to the power line and exposed to highest levels of magnetic fields. An increased risk for digestive tract neoplasms (SMR 3.57; 95% CI 1.49-8.58; 5 observed) was observed, which was mainly caused by pancreatic cancer., Discussion and Conclusion: Some increase in mortality of the overall cohort and especially of the highly exposed sub cohort was detected, notwithstanding the low power of the study. Other studies are currently on-going in the same area: a cross-sectional investigation on health status, an analysis of hospital discharge cards, a project for estimating individual exposure levels and a research in veterinary epidemiology. It is recommended to replicate the present study in areas presenting similar exposure patterns, in order to be able to pool data with the aim of estimating risk associated with the exposure levels of interest.

A cohort mortality study of rock salt workers was carried out in Volterra, Italy. The occupational risk factors identified during environmental hygiene surveys were high noise levels and exposure to dusts and to chrysotile asbestos. The cohort consists of 487 subjects (367 males and 120 females) employed in the mine between 1/1/1965 and 12/31/1989. At the end of follow-up, 387 individuals were alive (295 males and 92 females), and 100 were decreased (72 males and 28 females). For two decedents, the cause of death was unknown. Regional rates were used for the computation of standardized mortality ratios (SMRs). In the entire cohort, observed mortality for all causes was similar to expected (SMR = 98, 100 obs); SMR for all cancer was 127 (41 obs); for lung cancer, the SMR was 146 (10 obs). Two cases of pleural mesothelioma, both in males, resulted in a statistically significant elevation of this cause (SMR = 741, 90% confidence interval (CI) 131-2,332). Two malignant brain tumors were detected (SMR 328, 90% CI 58-1,032); one of these was identified as a secondary neoplasm with consideration of additional clinical information. Among males, mortality for all cancers was significantly increased (SMR = 140, 90% CI 106-192). The observed mortality for malignant tumors of the digestive and the respiratory systems was higher than expected. In women, two cases of malignant ovarian cancer were observed vs. 0.42 expected on the basis of the regional rates. Increased mortality from lung and pleural tumors was consistent with the exposure to asbestos, which has also been shown to play a role in the development of ovarian tumors. The main limitations of this study were the small number of subjects and the definition of exposure solely in terms of duration of employment. Further studies of rock salt workers are needed to elucidate our findings.

The mortality of 276 workers employed in a facility for the manufacturing and maintenance of railroad equipment has been studied in the town of Colleferro (province of Rome). The cohort was based on the 1968 payrolls, and follow-up was conducted up to 1988. Exposure to asbestos took place both during insulation (performed by specialized companies in the same workplaces where study subjects were operating) and during repair work. Mortality for all causes was lower than expected (45 observed, SMR: 71), while mortality from all neoplasms was consistent with expected figures (21 observed, SMR: 107). An increase for respiratory neoplasms was observed (10 observed, SMR: 138); the increase was statistically significant allowing for 20-30 years of latency (7 observed, SMR: 337).

Abstract Background The area of Gela was included among the 57 Italian polluted sites of national interest for environmental remediation because of its widespread contamination from a petrochemical complex. The present study investigates mortality and morbidity of the cohort of Gela petrochemical workers with the aim of disentangling occupational from residential risk. Methods Mortality was assessed for 5,627 men hired from 1960, year of the plant start-up, to 1993; it was followed up for vital status in the period 1960–2002. Morbidity was analysed for 5,431 workers neither dead nor lost to follow-up from 1960 to 2001 and was based on Hospital Discharge Records in the period 2001–2006. The work experience was classified in terms of job categories such as blue collars, white collars, and both – workers who shifted from blue to white collar (95%) or vice versa. An ad hoc mobility model was applied to define qualitative categories of residence in Gela, as residents and commuters. Standardized Mortality Ratios (SMRs) and Mortality Rate Ratios (MRRs) were computed, the latter by using a Poisson regression model. Morbidity was analyzed in terms of Hospital Discharge Odds Ratios (HDORs) through a logistic regression model. While performing the internal comparisons, white collars was the reference category for the job analysis, and commuters was the reference category for the residential analysis. Results In the light of epidemiological evidence about health risk from petrochemical industries in both occupational and environmental settings, and/or on the basis of information about occupational and residential contamination and health risk in the area of Gela, noteworthy results are shown for lung cancer [MRR: 2.11 (CI 90%; 0.96-4.63) in blue collars; 1.71 (1.09-2.69) in residents], respiratory diseases [HDOR: 2.0 (1.0-3.0) in blue collars; 1.4 (0.96-2.06) in residents] and genitourinary diseases [HDOR: 1.34 (1.06-1.68) in blue collars; 1.23 (1.04-1.45) in residents]. Conclusions The results support a role of the exposures in the occupational and residential settings, the latter due to the local ascertained contamination, in affecting the workers’ health. These results underline the urgent need of water, soil, air and food-chain monitoring programs, to discover active sources of exposure and consequently define public health interventions.

Background and aimThe implementation of idoneous management of hazardous waste, in contrast to illegal practices, is one of the environment and health priorities of the WHO. The aim of the present study, based on a collaborative agreement between the Italian National Health Institute and a Prosecution Office located in Naples North, was to evaluate the health effects of illegal landfills and burning of urban and hazardous waste in the territory of the Prosecution Office.MethodsThe municipalities included in the study territory were investigated with respect to the regional population. Regression analyses were performed in the study area between four classes of an environmental municipal indicator of waste risk (MRI) previously defined, computing the relative risks (RRs) in 2–4 MRI classes, with respect to the first MRI class (the least impacted). The prevalence of reproductive outcomes and cause-specific mortality and hospitalization were analyzed in the general population and in the 0–19-year-old population using SAS software.ResultsAn increase of mortality and hospitalization risk in both the genders of the whole area, with respect to regional population, were found for overall all cancer cases, cancer of the stomach, the liver, the lung and the kidney, and ischemic heart diseases. An increase of mortality for leukemias in the 0-19-year-old population and in hospitalization risk for certain conditions originating in the perinatal period were observed. Correlation between MRI and the risk of mortality from breast tumors in women (MRI class 2: RR = 1.06; MRI class 3: RR = 1.15; MRI class 4: RR = 1.11) and between MRI and the risk of hospitalization from testis tumors (MRI class 2: RR = 1.25; MRI class 3: RR = 1.31; MRI class 4: RR = 1.32) were found. The hospitalization risk from breast tumors and asthma exceeded significantly in both genders of three and four MRI classes. Among the 0-19-year-old population, correlation between MRI and hospitalization from leukemias (MRI class 2: RR = 1.48; MRI class 3: RR = 1.60; MRI class 4: RR = 1.41) and between MRI and the prevalence of preterm birth (MRI class 2: RR = 1.17; MRI class 3: RR = 1.08; MRI class 4: RR = 1.25) were found.ConclusionA correlation between health outcomes and the environmental pressure by uncontrolled waste sites was found. Notwithstanding the limitation of the study, the results promote implementing the actions of environmental remediation and the prosecution of illegal practices.

The article presents a case study of the population of Gela, Italy which depicted excess mortality and morbidity risks due to emissions from local petrochemical plant. Standardized Mortality Ratios (SMRs) for specific causes were calculated by using the mortality rates. Hospitalization risks were conducted by job and residence subcohorts. The article discusses the need of thorough investigations into the occupational and environmental sources of exposure in the area.

The town of Biancavilla, located on the lower flanks of Mt. Etna volcano, eastern Sicily (Italy), showed high mortality rates owing to malignant pleural neoplasms, a cause of death specifically related to exposure to asbestos fibres. An environmental survey indicated the stone quarry site of “Il Calvario” as a possible source of asbestos fibre exposure, while a mineralogical study allowed to identify the new asbestiform mineral “fluoro-edenite”. A joint epidemiological and environmental study was conducted to assess the characteristics of the outbreak of malignant mesothelioma and to test the assumption of a causal relation with exposure to fluoro-edenite. Due to the lack of awareness of fluoro-edenite releases, Il Calvario may not be the only source of the fibre, but is probably the main one. The evolution of the volume of material quarried from Il Calvario was studied on the basis of maps printed from 1896 to 1995, by using a digital elevation model. The natural and anthropogenic causes of the territorial spread of the newly discovered amphibole fibres are discussed relatively to a geo-volcanological, territorial and environmental evolution of the area affected. [ABSTRACT FROM AUTHOR]

A retrospective cohort mortality study was carried Out in 20 industrial factories in the Local Health Unit Bologna Sud (Emilia Romagna, Italy), where different rubber and plastics products were manufactured. The cohort consisted of 925 subjects (578 males and 347 females) employed for at least six months continuously; follow-up was between the beginning of operation of each factory, ranging between mid fifties and mid seventies, and 31 December 1989. For those exposed more than one year cause specific Standardized Mortality Ratios (SMRs) were computed using regional rates for comparison, 90% confidence intervals (Cl) were calculated assuming the Poisson distribution. Among the 748 subjects employed for more than one year (457 males and 291 females) there were no lost to follow-up, 54 individuals were dead (41 males and 13 females) and for three subjects the cause of death was unknown. The results showed that all causes mortality was above expectancy in the total cohort (SMR=123; 54 Obs; 90% Cl=97–154), among males (SMR=117; 41 Obs; 90% Cl=89–152) and females (SMR=143; 13 Obs; 90% Cl=85–228). Increased mortality for all malignant tumours was observed in the total cohort (SMR=150; 25 Obs; 90% Cl=104–209) and for both genders. All nine lung cancer cases were observed among males, the SMR was equal to 218 and was statistically significant; seven cases occurred at duration of exposure less than 10 years and six at latency up to 20 years. The interpretation in terms of causality of the present investigation is limited by the small number of observations and by exposure definition solely in terms of employment in the study factories; nonetheless the results are indicating the existence, in this group of rubber and plastics product makers, of an adverse health effect which deserve further investigation. [ABSTRACT FROM PUBLISHER]

Objectives. Adverse effects of waste management represent a public health issue. Mortality meta-analysis in Italian National Priority Contaminated Sites (NPCSs) with industrial waste landfills or illegal dumps is presented. Methods. 24 NPCSs include industrial waste landfills or illegal dumps. Class 1 (10 NPCSs with industrial waste landfills) and Class 2 (14 NPCSs with illegal dumps) were categorized. Random-effects model meta-analyses of Standardized Mortality Ratios non-adjusted (SMRs) and adjusted for Deprivation (DI-SMRs) computed for each CS (1995-2002) were performed for overall 24 NPCSs and the two classes. The North-Southern gradient was considered. Results. 24 CSs pooled-SMRs are significantly increased in both genders for cancer of liver (men: SMR = 1.13; women: SMR = 1.18), bladder (men: SMR = 1.06; women: SMR = 1.11), and for cirrhosis (men: SMR = 1.09; women: SMR = 1.13). In Class 2 the increase is confirmed in both genders for liver and bladder cancers and for cirrhosis and in men only for lung cancer. Congenital anomalies and adverse perinatal conditions are not increased. Conclusion. The results are consistent with the hypothesis of adverse health effects of non-adequately managed hazardous waste. Causal interpretation is not allowed, but the meta-analytic approach provides more confidence in the findings.

INTRODUCTION. The objective of this chapter is to study the health impact of the exposure to fibres with fluoro-edenitic composition on the residents in Biancavilla (Sicily, Italy), in terms of mortality and hospitalization. The diseases which international scientific literature indicates as associated with asbestos exposure were taken into consideration: mesothelioma of pleura, peritoneum, pericardium and tunica vaginalis testis, malignant neoplasm of larynx, malignant neoplasm of trachea, bronchus and lung, malignant neoplasm of ovary, pneumoconiosis; moreover, in order to describe the health profile of the study population, large groups of diseases were taken into consideration. MATERIAL AND METHODS. Current data (available in the Data Bases of the Unit of Statistics of ISS) regarding mortality and hospitalization were analyzed. Standardized Mortality Ratios, Standardized Hospitalization Ratios and Age-standardized Death Rates were calculated. The demographic background of the population residing in Biancavilla was also outlined. Conclusions. Our findings support the etiologic role of fibres with fluoro-edenitic composition in the occurrence of the above mentioned diseases, already observed in other studies.

INTRODUCTION: A neighbourhood of the city of Ferrara (Italy) was built over an area polluted with chlorinated organic compounds. A residential cohort study was performed to assess the health profile of the population living in the polluted area. METHODS: The residential history of 3475 subjects who had lived in the East quadrant neighbourhood in the period 1994-2010 was constructed. Mortality for the period 19942010 and cancer incidence for the years 1994-2007 were studied. Standardised mortality ratios (SMR) for 2632 subjects and standardised incidence ratios (SIR) for 2578 subjects who had lived for at least 5 years in the area under study were calculated. Indicators were calculated for males and females combined, using the population of Ferrara as reference population. RESULTS: The health profile of the population of the East quadrant neighbourhood, defined using mortality indicators for major groups of causes, is essentially similar to that of the city of Ferrara. Increased mortality rates for lung cancer (SMR 131, 90% CI 94-178) and incidence rates for some cancer sites, including liver (SIR 135, 90% CI 67-243) were observed, albeit on the basis of few cases and with wide confidence intervals. DISCUSSION: The likelihood of observing significant increases in risk is reduced by the sizes of the cohorts and the short follow-up period, but some findings nonetheless suggest that, as a precautionary measure, the cohort study should be continued in parallel with measures for the reclamation of the site and that this study should take the form of epidemiological surveillance.