Assessment of Deaths Attributable to Air Pollution: Should We Use Risk Estimates based on Time Series or on Cohort Studies?

Epidemiologic studies are crucial to the estimation of numbers of deaths attributable to air pollution. In this paper, the authors present a framework for distinguishing estimates of attributable cases based on time-series studies from those based on cohort studies, the latter being 5-10 times larger. The authors distinguish four categories of death associated with air pollution: A) air pollution increases both the risk of underlying diseases leading to frailty and the short term risk of death among the frail; B) air pollution increases the risk of chronic diseases leading to frailty but is unrelated to timing of death; C) air pollution is unrelated to risk of chronic diseases but short term exposure increases mortality among persons who are frail; and D) neither underlying chronic disease nor the event of death is related to air pollution exposure. Time-series approaches capture deaths from categories A and C, whereas cohort studies assess cases from categories A, B, and C. In addition, years of life lost can only be derived from cohort studies, where time to death is the outcome, while in time-series studies, death is a once-only event (no dimension in time). The authors conclude that time-series analyses underestimate cases of death attributable to air pollution and that assessment of the impact of air pollution on mortality should be based on cohort studie

Time series analysis of dengue incidence in Guadeloupe, French West Indies: Forecasting models using climate variables as predictors

BACKGROUND: During the last decades, dengue viruses have spread throughout the Americas region, with an increase in the number of severe forms of dengue. The surveillance system in Guadeloupe (French West Indies) is currently operational for the detection of early outbreaks of dengue. The goal of the study was to improve this surveillance system by assessing a modelling tool to predict the occurrence of dengue epidemics few months ahead and thus to help an efficient dengue control. METHODS: The Box-Jenkins approach allowed us to fit a Seasonal Autoregressive Integrated Moving Average (SARIMA) model of dengue incidence from 2000 to 2006 using clinical suspected cases. Then, this model was used for calculating dengue incidence for the year 2007 compared with observed data, using three different approaches: 1 year-ahead, 3 months-ahead and 1 month-ahead. Finally, we assessed the impact of meteorological variables (rainfall, temperature and relative humidity) on the prediction of dengue incidence and outbreaks, incorporating them in the model fitting the best. RESULTS: The 3 months-ahead approach was the most appropriate for an effective and operational public health response, and the most accurate (Root Mean Square Error, RMSE = 0.85). Relative humidity at lag-7 weeks, minimum temperature at lag-5 weeks and average temperature at lag-11 weeks were variables the most positively correlated to dengue incidence in Guadeloupe, meanwhile rainfall was not. The predictive power of SARIMA models was enhanced by the inclusion of climatic variables as external regressors to forecast the year 2007. Temperature significantly affected the model for better dengue incidence forecasting (p-value = 0.03 for minimum temperature lag-5, p-value = 0.02 for average temperature lag-11) but not humidity. Minimum temperature at lag-5 weeks was the best climatic variable for predicting dengue outbreaks (RMSE = 0.72). CONCLUSION: Temperature improves dengue outbreaks forecasts better than humidity and rainfall. SARIMA models using climatic data as independent variables could be easily incorporated into an early (3 months-ahead) and reliably monitoring system of dengue outbreaks. This approach which is practicable for a surveillance system has public health implications in helping the prediction of dengue epidemic and therefore the timely appropriate and efficient implementation of prevention activities

Optimizing Provider Recruitment for Influenza Surveillance Networks

The increasingly complex and rapid transmission dynamics of many infectious diseases necessitates the use of new, more advanced methods for surveillance, early detection, and decision-making. Here, we demonstrate that a new method for optimizing surveillance networks can improve the quality of epidemiological information produced by typical provider-based networks. Using past surveillance and Internet search data, it determines the precise locations where providers should be enrolled. When applied to redesigning the provider-based, influenza-like-illness surveillance network (ILINet) for the state of Texas, the method identifies networks that are expected to significantly outperform the existing network with far fewer providers. This optimized network avoids informational redundancies and is thereby more effective than networks designed by conventional methods and a recently published algorithm based on maximizing population coverage. We show further that Google Flu Trends data, when incorporated into a network as a virtual provider, can enhance but not replace traditional surveillance methods

Parallel assessment of male reproductive function in workers and wild rats exposed to pesticides in banana plantations in Guadeloupe

<p>Abstract</p> <p>Background</p> <p>There is increasing evidence that reproductive abnormalities are increasing in frequency in both human population and among wild fauna. This increase is probably related to exposure to toxic contaminants in the environment. The use of sentinel species to raise alarms relating to human reproductive health has been strongly recommended. However, no simultaneous studies at the same site have been carried out in recent decades to evaluate the utility of wild animals for monitoring human reproductive disorders. We carried out a joint study in Guadeloupe assessing the reproductive function of workers exposed to pesticides in banana plantations and of male wild rats living in these plantations.</p> <p>Methods</p> <p>A cross-sectional study was performed to assess semen quality and reproductive hormones in banana workers and in men working in non-agricultural sectors. These reproductive parameters were also assessed in wild rats captured in the plantations and were compared with those in rats from areas not directly polluted by humans.</p> <p>Results</p> <p>No significant difference in sperm characteristics and/or hormones was found between workers exposed and not exposed to pesticide. By contrast, rats captured in the banana plantations had lower testosterone levels and gonadosomatic indices than control rats.</p> <p>Conclusion</p> <p>Wild rats seem to be more sensitive than humans to the effects of pesticide exposure on reproductive health. We conclude that the concept of sentinel species must be carefully validated as the actual nature of exposure may varies between human and wild species as well as the vulnerable time period of exposure and various ecological factors.</p

Internações e óbitos e sua relação com a poluição atmosférica em São Paulo, 1993 a 1997

OBJETIVO: Investigar efeitos de curto prazo da poluição atmosférica na morbidade respiratória de menores de 15 anos e na mortalidade de idosos. MÉTODOS: O estudo foi realizado na cidade de São Paulo, Brasil. Foram analisadas as contagens diárias de admissões hospitalares, de menores de 15 anos e de mortes de idosos (>64 anos) no período de 1993 a 1997, em relação às variações diárias de poluentes atmosféricos (PM10, CO, O3). Foi utilizada para análise a regressão de Poisson em modelos aditivos generalizados. Os modelos foram ajustados para efeitos da tendência temporal, sazonalidade, dias da semana, fatores meteorológicos e autocorrelação. RESULTADOS: Variações do 10&deg; ao 90&deg; percentil dos poluentes foi significativamente associada com o aumento de admissões por doenças respiratórias em menores de 15 anos para PM10 (%RR=10,0), CO (%RR=6,1) e O3 (%RR=2,5). Associação similar foi encontrada para mortalidade em idosos e PM10 (%RR=8,1) e CO (%RR=7,9). CONCLUSÕES: Os resultados encontrados são coerentes com os estudos que apontam associação entre variações de curto prazo dos poluentes atmosféricos e incremento na morbidade e mortalidade nos grandes centros urbanos

Dietary intakes of population in period of epidemiologic transition (Martinique): The ESCAL Study (2003-2004)

info:eu-repo/semantics/nonPublishe

Enquête sur la Santé et les Comportements Alimentaires en Martinique (ESCAL Martinique 2003-2004): Résultats du volet « consommations alimentaires et apports nutritionnels »

info:eu-repo/semantics/publishe

Local and regional spread of chikungunya fever in the Americas

International audienceChikungunya fever (CHIKV), a viral disease transmitted by mosquitoes, is currently affecting several areas in the Caribbean. The vector is found in the Americas from southern Florida to Brazil, and the Caribbean is a highly connected region in terms of population movements. There is therefore a significant risk for the epidemic to quickly expand to a wide area in the Americas. Here, we describe the spread of CHIKV in the first three areas to report cases and between areas in the region. Local transmission of CHIKV in the Caribbean is very effective, the mean number of cases generated by a human case ranging from two to four. There is a strong spatial signature in the regional epidemic, with the risk of transmission between areas estimated to be inversely proportional to the distance rather than driven by air transportation. So far, this simple distance-based model has successfully predicted observed patterns of spread. The spatial structure allows ranking areas according to their risk of invasion. This characterisation may help national and international agencies to optimise resource allocation for monitoring and control and encourage areas with elevated risks to act

Recommandations de bonne pratique sur la prise en charge des femmes enceintes exposées au mercure organique et leurs enfants à naître. Recommandations de la Société de toxicologie clinique, associée à la Société française de toxicologie analytique, à la Société française de santé publique, à la Société francophone de santé environnement, à la Société française de pédiatrie, à la Société française de néonatalogie, au Collège national des gynécologues obstétriciens

National audienceIntroductionLa Société de toxicologie clinique (STC) a été sollicitée par les pouvoirs publics pour produire des recommandations concernant la prise en charge des femmes enceintes exposées au mercure organique et leurs enfants à naître.MéthodeCes recommandations, avec la participation d’experts appartenant à des sociétés savantes concernées par la prise en charge des femmes enceintes et/ou de leurs enfants, ont été établies selon la méthodologie des recommandations pour la pratique clinique définie par la Haute Autorité de santé (HAS).RésultatsLa principale source d’exposition de la population au méthylmercure (MeHg) est alimentaire, notamment par la consommation de poissons fortement contaminés. Les biomarqueurs d’exposition fiables pour la surveillance de l’imprégnation au MeHg des populations sont le mercure total dans les cheveux et dans le sang total. L’effet critique du MeHg est l’altération des fonctions cognitives résultant d’une exposition prénatale, et 11 μg/g de cheveux la valeur de la concentration capillaire de mercure maternelle, à partir de laquelle cet effet critique peut survenir chez l’enfant. La population prioritaire pour le dépistage est celle des femmes en âge de procréer, ainsi que les enfants âgés de moins de 7 ans, consommant plus de 2 portions de poissons par semaine, ou résidant dans les bourgs isolés de Guyane, particulièrement les femmes enceintes et leurs enfants allaités. Un suivi médical est recommandé pour les femmes enceintes ayant une concentration capillaire de mercure supérieure à 2,5 μg/g de cheveux (limite supérieure de l’intervalle de confiance du 95e percentile dans la population française) ainsi que pour leurs nouveau-nés. Si la concentration capillaire chez la mère et/ou l’enfant a dépassé 11 μg/g, l’enfant doit bénéficier d’un suivi neurodéveloppemental.ConclusionLes mesures de réduction alimentaire des expositions sont primordiales : l’indication de la chélation se discute dans les cas où des effets neurotoxiques sévères sont possibles. Dans ces recommandations, la prise en charge d’une exposition maternelle au MeHg ainsi que celle de l’enfant à naître sont détaillées dans un organigramme