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1.
Sci Total Environ ; 804: 150091, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34517316

RESUMO

BACKGROUND: Ambient air pollution exposure has been associated with higher mortality risk in numerous studies. We assessed potential variability in the magnitude of this association for non-accidental, cardiovascular disease, respiratory disease, and lung cancer mortality in a country-wide administrative cohort by exposure assessment method and by adjustment for geographic subdivisions. METHODS: We used the Belgian 2001 census linked to population and mortality register including nearly 5.5 million adults aged ≥30 (mean follow-up: 9.97 years). Annual mean concentrations for fine particulate matter (PM2.5), nitrogen dioxide (NO2), black carbon (BC) and ozone (O3) were assessed at baseline residential address using two exposure methods; Europe-wide hybrid land use regression (LUR) models [100x100m], and Belgium-wide interpolation-dispersion (RIO-IFDM) models [25x25m]. We used Cox proportional hazards models with age as the underlying time scale and adjusted for various individual and area-level covariates. We further adjusted main models for two different area-levels following the European Nomenclature of Territorial Units for Statistics (NUTS); NUTS-1 (n = 3), or NUTS-3 (n = 43). RESULTS: We found no consistent differences between both exposure methods. We observed most robust associations with lung cancer mortality. Hazard Ratios (HRs) per 10 µg/m3 increase for NO2 were 1.060 (95%CI 1.042-1.078) [hybrid LUR] and 1.040 (95%CI 1.022-1.058) [RIO-IFDM]. Associations with non-accidental, respiratory disease and cardiovascular disease mortality were generally null in main models but were enhanced after further adjustment for NUTS-1 or NUTS-3. HRs for non-accidental mortality per 5 µg/m3 increase for PM2.5 for the main model using hybrid LUR exposure were 1.023 (95%CI 1.011-1.035). After including random effects HRs were 1.044 (95%CI 1.033-1.057) [NUTS-1] and 1.076 (95%CI 1.060-1.092) [NUTS-3]. CONCLUSION: Long-term air pollution exposure was associated with higher lung cancer mortality risk but not consistently with the other studied causes. Magnitude of associations varied by adjustment for geographic subdivisions, area-level socio-economic covariates and less by exposure assessment method.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Adulto , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Poluição do Ar/análise , Poluição do Ar/estatística & dados numéricos , Censos , Estudos de Coortes , Exposição Ambiental/análise , Exposição Ambiental/estatística & dados numéricos , Humanos , Material Particulado/análise , Material Particulado/toxicidade
2.
Cancer Epidemiol ; 72: 101910, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33735659

RESUMO

BACKGROUND: A previous investigation of the occurrence of childhood acute leukemia around the Belgian nuclear sites has shown positive associations around one nuclear site (Mol-Dessel). In the following years, the Belgian Cancer Registry has made data available at the smallest administrative unit for which demographic information exists in Belgium, i.e. the statistical sector. This offers the advantage to reduce the potential misclassification due to large geographical scales. METHODS: The current study performed for the period 2006-2016 uses Poisson models to investigate (i) the incidence of childhood acute leukemia within 20 km around the four Belgian nuclear sites, (ii) exposure-response relationships between cancer incidence and surrogate exposures from the nuclear sites (distance, wind direction frequency and exposure by hypothetical radioactive discharges taking into account historical meteorological conditions). All analyses are carried out at statistical sector level. RESULTS: Higher incidence rate ratios were found for children <15 years (7 cases, RR = 3.01, 95% CI: 1.43;6.35) and children <5 years (< 5 cases, RR = 3.62, 95% CI: 1.35;9.74) living less than 5 km from the site of Mol-Dessel. In addition, there was an indication for positive exposure-response relationships with the different types of surrogate exposures. CONCLUSION: Results confirm an increased incidence of acute childhood leukemia around Mol-Dessel, but the number of cases remains very small. Random variation cannot be excluded and the ecological design does not allow concluding on causality. These findings emphasize the need for more in-depth research into the risk factors of childhood leukemia, for a better understanding of the etiology of this disease.


Assuntos
Leucemia/epidemiologia , Centrais Nucleares/estatística & dados numéricos , Adolescente , Bélgica/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Masculino , Sistema de Registros , Análise de Pequenas Áreas
3.
Environ Int ; 146: 106230, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33171378

RESUMO

Exposure of the thyroid gland to ionizing radiation at a young age is the main recognized risk factor for differentiated thyroid cancer. After the Chernobyl and Fukushima nuclear accidents, thyroid cancer screening was implemented mainly for children, leading to case over-diagnosis as seen in South Korea after the implementation of opportunistic screening (where subjects are recruited at healthcare sites). The aim of cancer screening is to reduce morbidity and mortality, but screening can also cause negative effects on health (with unnecessary treatment if over-diagnosis) and on quality of life. This paper from the SHAMISEN special issue (Nuclear Emergency Situations - Improvement of Medical And Health Surveillance) presents the principles of cancer screening, the lessons learned from thyroid cancer screening, as well as the knowledge on thyroid cancer incidence after exposure to iodine-131. The SHAMISEN Consortium recommends to envisage systematic health screening after a nuclear accident, only when appropriately justified, i.e. ensuring that screening will do more good than harm. Based on the experience of the Fukushima screening, the consortium does not recommend mass or population-based thyroid cancer screening, as the negative psychological and physical effects are likely to outweigh any possible benefit in affected populations; thyroid health monitoring should however be made available to persons who request it (regardless of whether they are at increased risk or not), accompanied with appropriate information and support.


Assuntos
Acidente Nuclear de Chernobyl , Acidente Nuclear de Fukushima , Neoplasias da Glândula Tireoide , Criança , Detecção Precoce de Câncer , Humanos , Japão , Qualidade de Vida , República da Coreia , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/epidemiologia
4.
Environ Res ; 189: 109914, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32980008

RESUMO

BACKGROUND: Living in green environments has been associated with various health benefits, but the evidence for positive effects on respiratory health in children is ambiguous. OBJECTIVE: To investigate if residential exposure to different types of green space is associated with childhood asthma prevalence in Belgium. METHODS: Asthma prevalence was estimated from sales data of reimbursed medication for obstructive airway disease (OAD) prescribed to children between 2010 and 2014, aggregated at census tract level (n = 1872) by sex and age group (6-12 and 13-18 years). Generalized log-linear mixed effects models with repeated measures were used to estimate effects of relative covers of forest, grassland and garden in the census tract of the residence on OAD medication sales. Models were adjusted for air pollution (PM10), housing quality and administrative region. RESULTS: Consistent associations between OAD medication sales and relative covers of grassland and garden were observed (unadjusted parameter estimates per IQR increase of relative cover, range across four strata: grassland, ß = 0.15-0.17; garden, ß = 0.13-0.17). The associations remained significant after adjusting for housing quality and chronic air pollution (adjusted parameter estimates per IQR increase of relative cover, range across four strata: grassland, ß = 0.10-0.14; garden, ß = 0.07-0.09). There was no association between OAD medication sales and forest cover. CONCLUSIONS: Based on aggregated data, we found that living in close proximity to areas with high grass cover (grasslands, but also residential gardens) may negatively impact child respiratory health. Potential allergic and non-allergic mechanisms that underlie this association include elevated exposure to grass pollen and fungi and reduced exposure to environmental biodiversity. Reducing the dominance of grass in public and private green space might be beneficial to reduce the childhood asthma burden and may simultaneously improve the ecological value of urban green space.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Asma , Poluição do Ar/análise , Asma/induzido quimicamente , Asma/tratamento farmacológico , Asma/epidemiologia , Bélgica/epidemiologia , Criança , Comércio , Exposição Ambiental/análise , Humanos , Parques Recreativos
5.
Environ Res ; 188: 109848, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32846640

RESUMO

BACKGROUND: Summer temperatures are expected to increase and heat waves will occur more frequently, be longer, and be more intense as a result of global warming. A growing body of evidence indicates that increasing temperature and heatwaves are associated with excess mortality and therefore global heating may become a major public health threat. However, the heat-mortality relationship has been shown to be location-specific and differences could largely be explained by the most frequent temperature. So far, in Belgium there is little known regarding the heat-mortality relationship in the different urban areas. OBJECTIVES: The objective of this study is to assess the heat-mortality relationship in the two largest urban areas in Belgium, i.e. Antwerp and Brussels for the warm seasons from 2002 until 2011 taking into account the effect of air pollution. METHODS: The threshold in temperature above which mortality increases was determined using segmented regressions for both urban areas. The relationship between daily temperature and mortality above the threshold was investigated using a generalized estimated equation with Poisson distribution to finally determine the percentage of deaths attributable to the effect of heat. RESULTS: Although only 50 km apart, the heat-mortality curves for the two urban areas are different. More specifically, an increase in mortality occurs above a maximum temperature of 25.2 °C in Antwerp and 22.8 °C in Brussels. We estimated that above these thresholds, there is an increase in mortality of 4.9% per 1 °C in Antwerp and of 3.1% in Brussels. During the study period, 1.5% of the deaths in Antwerp and 3.5% of the deaths in Brussels can be attributed to the effect of heat. The thresholds differed considerably from the most frequent temperature, particularly in Antwerp. Adjustment for air pollution attenuated the effect of temperature on mortality and this attenuation was more pronounced when adjusting for ambient ozone. CONCLUSION: Our results show a significant effect of temperature on mortality above a city-specific threshold, both in Antwerp and in Brussels. These findings are important given the ongoing global warming. Recurrent, intense and longer episodes of high temperature and expected changes in air pollutant levels will have an important impact on health in urban areas.


Assuntos
Poluição do Ar , Ozônio , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Bélgica/epidemiologia , Cidades , Temperatura Alta , Mortalidade , Ozônio/análise , Estações do Ano
6.
Int J Cancer ; 146(11): 3034-3043, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31745983

RESUMO

In Belgium, variations in thyroid cancer incidence were observed around the major nuclear sites. The present ecological study investigates whether there is an excess incidence of thyroid cancer among people living in the vicinity of the four nuclear sites at the smallest Belgian geographical level. Rate ratios were obtained from a Bayesian hierarchical model for areas of varying sizes around the nuclear sites. Focused hypothesis tests and generalized additive models were performed to test the hypothesis of a gradient in thyroid cancer incidence with increasing levels of surrogate exposures. No evidence was found for more incident cases of thyroid cancer near the two nuclear power plants. Regarding the two industrial and research nuclear sites, no evidence for a higher incidence in the vicinity of Mol-Dessel was observed, whereas a slightly nonsignificant higher incidence was found in the close vicinity of Fleurus. In addition, significant gradients for thyroid cancer incidence were observed with the different types of surrogate exposure considered in the 20 km area around the site of Fleurus (decreasing distance, increasing wind direction frequency and increasing exposure to estimated hypothetical radioactive discharges of iodine-131). In the investigation at the smallest Belgian geographical level, variations in thyroid cancer incidence were found around the Belgian nuclear sites. Significant exposure-response relationships were also observed for the site of Fleurus. Further investigations into these findings could be useful to allow inferring causal relationships on the origin of variations in incidence and to provide information at the individual level.


Assuntos
Exposição Ambiental/efeitos adversos , Neoplasias Induzidas por Radiação/epidemiologia , Centrais Nucleares/estatística & dados numéricos , Liberação Nociva de Radioativos/estatística & dados numéricos , Neoplasias da Glândula Tireoide/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bélgica/epidemiologia , Criança , Pré-Escolar , Feminino , Geografia , Humanos , Incidência , Lactente , Recém-Nascido , Radioisótopos do Iodo/efeitos adversos , Masculino , Pessoa de Meia-Idade , Radiação Ionizante , Tempo (Meteorologia) , Adulto Jovem
7.
Sci Total Environ ; 649: 620-628, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30176473

RESUMO

Exposure to ambient air pollution has been associated with various adverse health effects including respiratory, cardiovascular and neurological diseases. Exposure data for some specific pollutants and settings are however still insufficient and mechanisms underlying negative health outcomes are not fully elucidated. This pilot study aimed to assess individual exposure to three traffic-related air pollutants, black carbon (BC), polycyclic aromatic hydrocarbons (PAHs) and benzene, and the relationship with respiratory and oxidative stress outcomes in a cross-sectional sample of 48 green space workers in Brussels, Belgium. Participants were followed during four consecutive working days in 2016-2017 during which their individual exposure to BC, PAHs, benzene and more generally air pollution was measured using aethalometers, urinary biomarkers (1-hydroxypyrene, 1-naphthol, 2-naphthol, S-phenylmercapturic acid) and questionnaires. Data on respiratory health and oxidative stress were collected using questionnaires and respiratory/urinary biomarkers (exhaled nitric oxide [NO], 8-hydroxydeoxyguanosine [8-OHdG]). Associations between exposure and health outcomes were investigated using comparison tests and linear regression models, after stratification by present-day smoking status. Spatial variation in BC exposure was high, with concentrations varying between 0.26 and 5.69 µg/m3. The highest levels were recorded during transport and, to a lesser extent, in green spaces located in the vicinity of roads with high traffic intensity. Concentrations of PAHs and benzene biomarkers did not systematically exceed the limits of detection. Among smokers, respiratory inflammation increased linearly with exposure to BC measured over the four days of follow-up (ß = 8.73, 95% CI: 4.04, 13.41). Among non-smokers, oxidative stress increased linearly with BC measured on the fourth day (ß = 2.88, 95% CI: 1.52, 4.24). Despite some limitations, this work supports the hypothesis that BC induces respiratory inflammation and oxidative stress. It also highlights the value of this compound as well as exhaled NO and urinary 8-OHdG biomarkers to detect early/mild effects of air pollution.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Benzeno/efeitos adversos , Exposição Ambiental , Hidrocarbonetos Policíclicos Aromáticos/efeitos adversos , Fuligem/efeitos adversos , Emissões de Veículos/análise , Bélgica , Cidades , Estudos Transversais , Monitoramento Ambiental , Humanos , Inflamação/induzido quimicamente , Estresse Oxidativo , Projetos Piloto , Sistema Respiratório/imunologia , Sistema Respiratório/fisiopatologia , População Urbana
8.
Artigo em Inglês | MEDLINE | ID: mdl-28858225

RESUMO

The present study investigates whether there is an excess incidence of thyroid cancer among people living in the vicinity of the nuclear sites in Belgium. Adjusted Rate Ratios were obtained from Poisson regressions for proximity areas of varying sizes. In addition, focused hypothesis tests and generalized additive models were performed to test the hypothesis of a gradient in thyroid cancer incidence with increasing levels of surrogate exposures. Residential proximity to the nuclear site, prevailing dominant winds frequency from the site, and simulated radioactive discharges were used as surrogate exposures. No excess incidence of thyroid cancer was observed around the nuclear power plants of Doel or Tihange. In contrast, increases in thyroid cancer incidence were found around the nuclear sites of Mol-Dessel and Fleurus; risk ratios were borderline not significant. For Mol-Dessel, there was evidence for a gradient in thyroid cancer incidence with increased proximity, prevailing winds, and simulated radioactive discharges. For Fleurus, a gradient was observed with increasing prevailing winds and, to a lesser extent, with increasing simulated radioactive discharges. This study strengthens earlier findings and suggests increased incidences in thyroid cancer around two of the four Belgian nuclear sites. Further analyses will be performed at a more detailed geographical level.


Assuntos
Centrais Nucleares , Neoplasias da Glândula Tireoide/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Bélgica/epidemiologia , Criança , Pré-Escolar , Feminino , Geografia , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Neoplasias da Glândula Tireoide/etiologia , Adulto Jovem
9.
Environ Int ; 98: 129-136, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27823799

RESUMO

BACKGROUND: Recent studies suggest that exposure to greenness favors several health outcomes. We assessed whether living in the proximity of greener areas was related to prostate cancer incidence in a population-based case-control study in Montreal, Canada. MATERIALS AND METHODS: Interviews eliciting lifetime addresses were conducted with 1933 prostate cancer cases diagnosed in 2005-2009 and 1994 population controls. Odds ratios (OR) and 95% confidence intervals (CI) estimated the association between residential greenness, both at recruitment (2005-2009) and about ten years prior (1996), defined by the normalized difference vegetation index (NDVI) around the home, and prostate cancer risk. Three models were developed adjusting for age, individual characteristics, and individual and ecological characteristics, estimating relative risk in relation to an interquartile range (IQR) increase of the NDVI. RESULTS: We observed inverse associations between greenness measured within home buffers of 150m, 300m, 500m and 1000m, at both time points, and risk of prostate cancer, independently of individual and ecological characteristics. For instance, using a buffer of 300m, the OR for an IQR increase of 0.11 in NDVI at the time of recruitment was 0.82 (95%CI 0.74-0.92). The corresponding OR for an IQR increase of 0.15 in NDVI in 1996 was 0.86 (95%CI 0.74-1.00). There were little differences in risks according to buffer size, the time point of exposure, when considering prostate cancer aggressiveness, or when restricting controls to men recently screened for prostate cancer to reduce the likelihood of undiagnosed cancer among them. CONCLUSION: Men living in greener areas, either recently or about a decade earlier, had lower risks of prostate cancer, independently of socio-demographic and lifestyle factors. These observations are novel and require confirmation.


Assuntos
Meio Ambiente , Parques Recreativos , Neoplasias da Próstata/epidemiologia , Idoso , Canadá , Estudos de Casos e Controles , Humanos , Incidência , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Razão de Chances , Quebeque/epidemiologia , Risco
10.
Environ Health Perspect ; 125(4): 714-720, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27483500

RESUMO

BACKGROUND: Exposures to high-dose ionizing radiation and high-dose rate ionizing radiation are established risk factors for childhood acute leukemia (AL). The risk of AL following exposure to lower doses due to natural background radiation (NBR) has yet to be conclusively determined. METHODS: AL cases diagnosed over 1990-2009 (9,056 cases) were identified and their municipality of residence at diagnosis collected by the National Registry of Childhood Cancers. The Geocap study, which included the 2,763 cases in 2002-2007 and 30,000 population controls, was used for complementary analyses. NBR exposures were modeled on a fine scale (36,326 municipalities) based on measurement campaigns and geological data. The power to detect an association between AL and dose to the red bone marrow (RBM) fitting UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) predictions was 92%, 45% and 99% for exposure to natural gamma radiation, radon and total radiation, respectively. RESULTS: AL risk, irrespective of subtype and age group, was not associated with the exposure of municipalities to radon or gamma radiation in terms of yearly exposure at age reached, cumulative exposure or RBM dose. There was no confounding effect of census-based socio-demographic indicators, or environmental factors (road traffic, high voltage power lines, vicinity of nuclear plants) related to AL in the Geocap study. CONCLUSIONS: Our findings do not support the hypothesis that residential exposure to NBR increases the risk of AL, despite the large size of the study, fine scale exposure estimates and wide range of exposures over France. However, our results at the time of diagnosis do not rule out a slight association with gamma radiation at the time of birth, which would be more in line with the recent findings in the UK and Switzerland.


Assuntos
Radiação de Fundo , Leucemia Induzida por Radiação/epidemiologia , Exposição à Radiação/estatística & dados numéricos , Criança , Feminino , França/epidemiologia , Raios gama , Habitação/estatística & dados numéricos , Humanos , Masculino , Radiação Ionizante , Radônio , Medição de Risco
11.
Cancer Epidemiol ; 45: 11-17, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27664387

RESUMO

BACKGROUND: Alcohol intake may increase the risk of prostate cancer (PCa). Many previous studies harbored important methodological limitations. METHODS: We conducted a population-based case-control study of PCa comprising 1933 cases and 1994 controls in Montreal, Canada. Lifetime alcohol consumption was elicited, by type of beverage, during in-person interviews. Odds ratios (OR) and 95% confidence intervals (CI) assessed the association between alcohol intake and PCa risk, adjusting for potential confounders and considering the subjects' PCa screening history. RESULTS: We observed a weak, non-significant positive association between high consumption of total alcohol over the lifetime and risk of high-grade PCa (OR=1.18, 95% CI 0.81-1.73). Risk estimates were more pronounced among current drinkers (OR=1.40, 95%CI 1.00-1.97), particularly after adjusting for the timing of last PCa screening (OR=1.52, 95%CI 1.07-2.16). These associations were largely driven by beer consumption. The OR for high-grade PCa associated with high beer intake was 1.37 (95%CI 1.00-1.89); it was 1.49 (95%CI 0.99-2.23) among current drinkers and 1.68 (95% CI 1.10-2.57) after adjusting for screening recency. High cumulative consumption of spirits was associated with a lower risk of low-grade PCa (OR=0.75, 95%CI 0.60-0.94) but the risk estimate no longer achieved statistical significance when restricting to current users. No association was found for wine consumption. CONCLUSION: Findings add to the accumulating evidence that high alcohol consumption increases the risk of high-grade PCa. This association largely reflected beer intake in our population, and was strengthened when taking into account PCa screening history.


Assuntos
Consumo de Bebidas Alcoólicas/efeitos adversos , Neoplasias da Próstata/etiologia , Adulto , Idoso , Canadá , Estudos de Casos e Controles , Detecção Precoce de Câncer , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/diagnóstico , Fatores de Risco
12.
Radiat Environ Biophys ; 52(2): 195-209, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23529777

RESUMO

Previous epidemiological studies and quantitative risk assessments (QRA) have suggested that natural background radiation may be a cause of childhood leukemia. The present work uses a QRA approach to predict the excess risk of childhood leukemia in France related to three components of natural radiation: radon, cosmic rays and terrestrial gamma rays, using excess relative and absolute risk models proposed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Both models were developed from the Life Span Study (LSS) of Japanese A-bomb survivors. Previous risk assessments were extended by considering uncertainties in radiation-related leukemia risk model parameters as part of this process, within a Bayesian framework. Estimated red bone marrow doses cumulated during childhood by the average French child due to radon, terrestrial gamma and cosmic rays are 4.4, 7.5 and 4.3 mSv, respectively. The excess fractions of cases (expressed as percentages) associated with these sources of natural radiation are 20 % [95 % credible interval (CI) 0-68 %] and 4 % (95 % CI 0-11 %) under the excess relative and excess absolute risk models, respectively. The large CIs, as well as the different point estimates obtained under these two models, highlight the uncertainties in predictions of radiation-related childhood leukemia risks. These results are only valid provided that models developed from the LSS can be transferred to the population of French children and to chronic natural radiation exposures, and must be considered in view of the currently limited knowledge concerning other potential risk factors for childhood leukemia. Last, they emphasize the need for further epidemiological investigations of the effects of natural radiation on childhood leukemia to reduce uncertainties and help refine radiation protection standards.


Assuntos
Radiação Cósmica/efeitos adversos , Raios gama/efeitos adversos , Leucemia Induzida por Radiação/etiologia , Modelos Biológicos , Radônio/efeitos adversos , Criança , Pré-Escolar , Feminino , França/epidemiologia , Humanos , Lactente , Leucemia Induzida por Radiação/epidemiologia , Masculino , Medição de Risco
13.
Eur J Cancer Prev ; 21(4): 367-74, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22108445

RESUMO

Childhood acute leukaemia (AL) accounts for a third of childhood cancers. Analysing the spatial distribution of the incidence of AL and its lymphoblastic and myeloblastic subtypes may contribute to the identification of risk factors. This national registry-based study aimed to evaluate global spatial heterogeneity in the incidence rates of AL and to detect clusters in France over the period 1990-2006 on the 'living-zone' scale. Between 1990 and 2006, 7675 cases of AL were registered in the National Registry of Childhood Haematopoietic malignancies. Their spatial distribution in the 1895 'living zone' was first evaluated with two tests for global spatial heterogeneity (Potthoff-Witthinghill and Rogerson's tests) and then with the SaTScan and FleXScan methods, which aim to locate spatial and space-time clusters. Over 1990-2006, no spatial heterogeneity of AL or its subtypes was evidenced. In addition, none of the most likely clusters identified with SaTScan and FleXScan over the whole period was significant, and the systematic search for space-time clusters yielded nonsignificant results. However, when three subperiods were considered, five statistically significant nonoverlapping spatial clusters were identified. This study did not find evidence of any global spatial heterogeneity of AL incidence rates in France over the period 1990-2006. Although no significant spatial cluster was detected over the whole period, the study identified a few significant spatial clusters in specific periods. Even though the significance levels of those clusters do not strongly support the existence of local risk factors, the clusters may still reflect a slight impact of shared risk factors, including background environmental exposures, which require further investigation.


Assuntos
Leucemia/epidemiologia , Características de Residência/estatística & dados numéricos , Doença Aguda , Adolescente , Idade de Início , Criança , Pré-Escolar , Análise por Conglomerados , Demografia , França/epidemiologia , Humanos , Incidência , Lactente , Recém-Nascido , Sistema de Registros , Fatores de Tempo
14.
Int J Health Geogr ; 10: 53, 2011 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-21970516

RESUMO

BACKGROUND: For many years, the detection of clusters has been of great public health interest. Several detection methods have been developed, the most famous of which is the circular scan method. The present study, which was conducted in the context of a rare disease distributed over a large territory (7675 cases registered over 17 years and located in 1895 units), aimed to evaluate the performance of several of the methods in realistic hot-spot cluster situations. METHODS: All the methods considered aim to identify the most likely cluster area, i.e. the zone that maximizes the likelihood ratio function, among a set of cluster candidates. The circular and elliptic scan methods were developed to detect regularly shaped clusters. Four other methods that focus on irregularly shaped clusters were also considered (the flexible scan method, the genetic algorithm method, and the double connected and maximum linkage spatial scan methods). The power of the methods was evaluated via Monte Carlo simulations under 27 alternative scenarios that corresponded to three cluster population sizes (20, 45 and 115 expected cases), three cluster shapes (linear, U-shaped and compact) and three relative risk values (1.5, 2.0 and 3.0). RESULTS: Three situations emerged from this power study. All the methods failed to detect the smallest clusters with a relative risk lower than 3.0. The power to detect the largest cluster with relative risk of 1.5 was markedly better for all methods, but, at most, half of the true cluster was captured. For other clusters, either large or with the highest relative risk, the standard elliptic scan method appeared to be the best method to detect linear clusters, while the flexible scan method localized the U-shaped clusters more precisely than other methods. Large compact clusters were detected well by all methods, with better results for the circular and elliptic scan methods. CONCLUSIONS: The elliptic scan method and flexible scan method seemed the most able to detect clusters of a rare disease in a large territory. However, the probability of detecting small clusters with relative risk lower than 3.0 remained low with all the methods tested.


Assuntos
Surtos de Doenças/estatística & dados numéricos , Leucemia/epidemiologia , Vigilância da População/métodos , Doenças Raras/epidemiologia , Doença Aguda , Criança , Análise por Conglomerados , Métodos Epidemiológicos , França/epidemiologia , Humanos , Método de Monte Carlo
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