[AIRBAg study: preliminary results after one year of screening for COPD in dairy farmers]. / Étude AIRBAg : résultats préliminaires après un an de dépistage de la BPCO agricole.

INTRODUCTION: The AIRBAg study screens for bronchial obstruction in dairy farmers. We present the preliminary results after one year. METHODS: A prospective screening study based on questionnaires and electronic mini-spirometry (Néo-6(®)) that includes a representative sample of dairy farmers from the departments of Morbihan and Île-et-Vilaine in Brittany. The dairy farmers had an occupational medicine appointment and, if they demonstrated at least one marker of possible bronchial obstruction (chronic cough, chronic bronchitis, dyspnoea, wheezing, FEV1/FEV6<0.8), they were referred to a pulmonologist. The data we present here were extracted from the occupational medicine appointments because the pulmonologists' appointments are still running. RESULTS: Among the 277 dairy farmers included, 125 (45%) demonstrated "possible bronchial obstruction". The total score of the CAT questionnaire was higher in these farmers (9.1±6.2 versus 5.8±4.0; P<0.0001). In multivariate analysis markers of "possible bronchial obstruction" were eczema, manual foddering and duration of mechanical straw litter spreading. CONCLUSION: Occupational medicine appointments identified markers of "possible bronchial obstruction". We will have the complete results from AIRBAg study in 2015.

Evolution of sperm quality in men living in the vicinity of a municipal solid waste incinerator possibly correlated with decreasing dioxins emission levels.

The objective was to examine the impact on sperm parameters of environmental exposure to dioxins around a municipal waste incinerator initially with high emission levels and during reduction levels. An ecological study with quasi-experimental conditions was performed in patients of a reproductive laboratory. The first semen analyses of 251 men living in Besançon, France, between 2001 and 2007, were included. To analyse the contribution of direct exposure (inhalation), the calendar time was dichotomised in two periods 2001-2003 versus 2004-2007 and used as a proxy for exposure. Regarding the indirect exposure pathway (food), the statistical analysis was made with a nonparametric test to assess the trends. There was a negative correlation between the year of exposure and the percentage of abnormal mid-piece and the multiple abnormalities index, even after adjusting for age and days abstention from inter-course. A positive correlation was found between the progressive motile sperm count and the period of exposure. These findings are to be put into the context of a drastic reduction in emissions of dioxins. Our results suggest an effect of chronic exposure to dioxins on spermiogenesis with more abnormalities. These results should be confirmed with concentration measurements of dioxins in infertile men.

Variability of radiofrequency exposure across days of the week: a population-based study.

Although measurement of the radiofrequency (RF) exposure can today be performed with personal exposure meters, this approach would be very expensive and time-consuming for large studies, and long term measurements would require considerable commitment of the study participants. Thus, there is a need for validated exposure assessment methods that do not require individual measurements for each study participant. Among the potential predictors, one of the most amenable to being recorded adequately is the day of the week. Drawing upon an existing population-based study, our goal was therefore to assess variability of individual RF exposure across days of the week. The random sample consisted of 34 people who were supplied with a personal exposure meter for seven consecutive days, and kept a time-location-activity diary. A total of 225,414 electric field strength measurements were recorded in 12 different RF bands. Summary statistics were calculated with the robust regression on order statistics method. We found evidence for statistically significant variability of individual RF exposure across days of the week, though the relative magnitude of the differences observed was small. Larger studies are needed to validate these results and determine whether day of the week is an important determinant for inclusion in individual RF exposure prediction models that remain urgently needed to conduct epidemiological studies on potential health effects.

Environmental risk factors for haemorrhagic fever with renal syndrome in a French new epidemic area.

In France, haemorrhagic fever with renal syndrome (HFRS) is endemic along the Belgian border. However, this rodent-borne zoonosis caused by the Puumala virus has recently spread south to the Franche-Comté region. We investigated the space-time distribution of HFRS and evaluated the influence of environmental factors that drive the hantavirus reservoir abundance and/or the disease transmission in this area. A scan test clearly indicated space-time clustering, highlighting a single-year (2005) epidemic in the southern part of the region, preceded by a heat-wave 2 years earlier. A Bayesian regression approach showed an association between a variable reflecting biomass (normalized difference vegetation index) and HFRS incidence. The reasons why HFRS cases recently emerged remain largely unknown, and climate parameters alone do not reliably predict outbreaks. Concerted efforts that combine reservoir monitoring, surveillance, and investigation of human cases are warranted to better understand the epidemiological patterns of HFRS in this area.

Residential exposure to radiofrequency fields from mobile phone base stations, and broadcast transmitters: a population-based survey with personal meter.

OBJECTIVES: Both the public perceptions, and most published epidemiologic studies, rely on the assumption that the distance of a particular residence from a base station or a broadcast transmitter is an appropriate surrogate for exposure to radiofrequency fields, although complex propagation characteristics affect the beams from antennas. The main goal of this study was to characterise the distribution of residential exposure from antennas using personal exposure meters. METHODS: A total of 200 randomly selected people were enrolled. Each participant was supplied with a personal exposure meter for 24 h measurements, and kept a time-location-activity diary. Two exposure metrics for each radiofrequency were then calculated: the proportion of measurements above the detection limit (0.05 V/m), and the maximum electric field strength. Residential address was geocoded, and distance from each antenna was calculated. RESULTS: Much of the time, the recorded field strength was below the detection level (0.05 V/m), the FM band standing apart with a proportion above the detection threshold of 12.3%. The maximum electric field strength was always lower than 1.5 V/m. Exposure to GSM and DCS waves peaked around 280 m and 1000 m from the antennas. A downward trend was found within a 10 km range for FM. Conversely, UMTS, TV 3, and TV 4&5 signals did not vary with distance. CONCLUSIONS: Despite numerous limiting factors entailing a high variability in radiofrequency exposure assessment, but owing to a sound statistical technique, we found that exposures from GSM and DCS base stations increase with distance in the near source zone, to a maximum where the main beam intersects the ground. We believe these results will contribute to the ongoing public debate over the location of base stations and their associated emissions.

Clusters of autochthonous hepatitis A cases in a low endemicity area.

At the University Hospital of Besançon (département of Doubs, France), an unusually high number of patients were hospitalized for hepatitis A during the 1999-2000 period, some of whom had not travelled abroad. This prompted us to conduct an investigation on a population basis and search for clusters of cases possibly related to local sources of contamination. Accordingly, case definition was restricted to autochthonous cases. During the 1999-2002 period, 45 autochthonous cases were classified as possibly originating from local environmental sources. A space-time scan statistic detected one most likely cluster (standardized incidence ratio 20.63, 95% confidence interval 10.6-37.1), consisting of 11 persons (of whom five children had attended the same swimming pool). It remained significant in a sensitivity analysis, strongly supporting the hypothesis of an environmental source of contamination. This study reveals the necessity of regular surveillance for hepatitis A and raises the issue of virological surveys of pool waters.

Increasing trend of childhood type 1 diabetes in Franche-Comté (France): analysis of age and period effects from 1980 to 1998.

AIMS/HYPOTHESIS: A study was conducted by the Franche-Comté Regional Association of Private Practitioners (Union Régionale des Médecins Libéraux de Franche-Comté) to assess trends in childhood-onset Type 1 diabetes in this administrative region of France, between 1980 and 1998. METHODS: Cases of childhood-onset Type 1 diabetes (aged 0-14 years) were retrospectively recorded with the help of general practitioners, private specialists and hospitals in the Franche-Comté and surrounding administrative regions. Incidence rates and trends during the period were analysed using Poisson regression. RESULTS: During the 19-year study period, 308 cases of childhood-onset Type 1 diabetes were identified. The level of case ascertainment was estimated to be 80.6% (95% CI: 74.7, 87.4). The male-to-female sex ratio was 1.03. The World standardised incidence rate was 6.90/100,000. The incidence rate was 6.03 (95% CI: 4.76, 7.53) for children aged 0 to 4 years, 6.45 (95% CI: 5.23, 7.88) for children aged 5-9 years and 8.56 (95% CI: 7.18, 10.13) for those aged 10-14 years. The annual increase rate was 4.9%, continuous and regular, without any deviation. This trend did not differ according to gender or age group. CONCLUSION/INTERPRETATION: These results confirm that the incidence and the increase rate in childhood Type 1 diabetes in France are average compared to in other European countries over an extended period of time. Furthermore, the regular and linear increase in incidence supports the hypothesis of causal environmental factors diffusing over time. The complementary data provided also illustrate the role that private practitioners may play by their implication in epidemiology and public health.

Blood warm reperfusion: a necessary adjunct to heart-valve surgery in low-risk patients?

AIM: The aim of this prospective, randomized study was to determine whether blood warm reperfusion improves myocardial protection provided by cold crystalloid cardioplegia in patients undergoing first-time elective heart-valve surgery, using cardiac troponin I release as the criterion for evaluating the adequacy of myocardial protection. METHODS: Seventy patients with a left ventricular ejection fraction greater than 40% were randomly assigned to 1 of 2 myocardial protection strategies: 1) cold crystalloid cardioplegia with no reperfusion or 2) cold crystalloid cardioplegia followed by 2-minute blood warm reperfusion before aortic unclamping. Cardiac troponin I concentrations were measured in serial venous blood samples drawn immediately prior to cardiopulmonary bypass and after aortic unclamping at 6, 9, 12, and 24 h. RESULTS: Randomization produced 2 equivalent groups. The total amount of cardiac troponin I released (7.17+/- 14.8 mg in the crystalloid cardioplegia with no reperfusion group and 5.82+/-4.66 mg in the crystalloid cardioplegia followed by blood warm reperfusion group) was not different (P > 0.2). Cardiac troponin I concentration did not differ for any sample in either of the 2 groups. The total amount of cardiac troponin I released was higher in patients who required inotropic support (9.14 +/-16.2 mg) than those who did not (4.73+/-4.52 mg; P = 0.009). CONCLUSIONS: Our study shows that adding blood warm reperfusion to cold crystalloid cardioplegia provides no additional myocardial protection in low-risk patients undergoing heart-valve surgery.

[Dioxin emissions and soft-tissue sarcoma: results of a population-based case-control study]. / Emission de dioxines et sarcomes des tissus mous: étude cas-témoins en population.

BACKGROUND: In 1998, the French Ministry of Environment revealed that of 71 French municipal solid waste incinerators processing more than 6 metric tons of material per hour, dioxin emission from 15 of them was above the 10 ng international toxic equivalency factor/m3 (including Besançon, emitting 16.3 ng international toxic equivalency factor/m3) which is substantially higher than the 0.1 international toxic equivalency factor/m3 prescribed by a European directive of 1994. In 2000, a macrospatial epidemiological study undertaken in the administrative district of Doubs, identified two significant clusters of soft-tissue sarcoma and non Hodgkin lymphoma in the vicinity of the municipal solid waste incinerator of Besançon. This microspatial study (at the Besançon city scale), was designed to test the association between the exposure to dioxins emitted by the municipal solid waste incinerator of Besançon and the risk of soft-tissue sarcoma. METHODS: Ground-level concentrations of dioxin were modeled with a dispersion model (Air Pollution Control 3 software). Four increasing zones of exposure were defined. For each case of soft tissue sarcoma, ten controls were randomly selected from the 1990 census database and matched for gender and age. A geographic information system allowed the attribution of a dioxin concentration category to cases and controls, according to their place of residence. RESULTS: Thirty-seven cases of soft tissue sarcoma were identified by the Doubs cancer registry between 1980 and 1995, corresponding to a standardized incidence (French population) of 2.44 per 100,000 inhabitants. Compared with the least exposed zone, the risk of developing a soft tissue sarcoma was not significantly increased for people living in the more exposed zones. CONCLUSION: Before definitely concluding that there is no relationship between the exposure to dioxin released by a solid waste incinerator and soft tissue sarcoma, a nationwide investigation based on other registries should be conducted.

Multilevel modelling and malaria: a new method for an old disease.

BACKGROUND: Malaria is influenced by a web of individual and ecological factors, i.e. factors relating to people and relating to environment. For a long time analysing these factors concurrently has raised statistical problems. Multilevel modelling provides a new attractive solution, which is still uncommon in tropical medicine. METHODS: Using an actual data set of 3864 individuals from 38 villages of the Highland Madagascar, a two-level modelling process is presented. Individual malaria parasitaemia is modelled step by step according to age (individual factor), altitude, and DDT indoor house-spraying status (village factors). RESULTS: The hierarchical organization of a data set in levels, fixed and random effects, and cross-level interactions are considered. Accurate estimations of standard errors, impact of unknown or unmeasured variables quantified and accounted for through random effects, are the highlighted advantages of multilevel modelling. CONCLUSION: While not denying the importance of understanding an aetiological chain, the authors recommend an increased use of multilevel modelling, mainly to identify accurately ecological targets for public health policy.

[Cluster analysis in geographical epidemiology: the use of several statistical methods and comparison of their results]. / L'analyse de cluster en épidémiologie géographique: utilisation de plusieurs méthodes statistiques et comparaison de leurs résultats.

BACKGROUND: The increasing interest in environmental epidemiology has been followed by the development of many statistical tests for detecting disease clustering near a point source. The objectives of this study were to compare several tests to detect disease clustering, among which modelisation using Markov Chain Monte Carlo methods. METHODS: We compared six statistical methods for detecting disease clustering of bladder cancer around an industrial centre of Isère (France) for the period 1983-1997: Stone's test, score test, and two log-linear modelisations (with and without corrections for extra-Poisson variations) using two ways of parameters estimation (maximum likelihood and Markov Chain Monte Carlo methods). RESULTS: The results of the Stone test and the score test are not in favour of a higher risk of bladder cancer around the considered point source. The conclusions brought by the log linear modelisations are the same, but the results obtained using the Markov Chain Monte Carlo Method are very dependant of prior distributions determined for the different parameters. CONCLUSION: Markov Chain Monte Carlo methods, which allow taking into account complex geographical effects, seem well adapted to cluster analysis in geographical epidemiology. However, they remain difficult to implement.

Blood pressure, body mass index and socio-economic status in the urban population of Antananarivo (Madagascar).

In many developing countries and especially those in the Indian Ocean, the prevalences of hypertension and obesity have increased markedly over the past decade. In a community-based study set in Antananarivo, the capital of Madagascar, multi-level modelling has now been used to look for associations between blood pressure or body mass index (BMI) and levels of occupation, education and income, among 773 adults. Many (23%) of the subjects had elevated blood pressure (i.e. over 140/90 mmHg). The prevalence of such elevated blood pressure increased with age - with an odds ratio (OR) of 2.16 and a corresponding 95% confidence interval (CI) of 1.81-2.58 for each 10-year increase - but decreased with educational level (high school: OR=0.74; CI = 0.41-1.31) and income (fourth quartile: OR= 0.66; CI = 0.35-1.27). The BMI data indicated that 18.4% of the subjects were underweight, 6.0% were overweight but not obese and 2.4% were obese. Being overweight was directly associated with level of occupation (management level: OR= 3.49; CI = 1.18-10.29) and income (fourth quartile: OR= 3.55;CI = 1.48-8.50). Despite the trends, underweight and overweight individuals and cases of elevated blood pressure were found to co-exist in all socio-economic classes.

Respiratory morbidity in a population of French dental technicians.

AIMS: To compare wage earner dental technicians with non-exposed salaried subjects for the prevalence of respiratory symptoms and function, and chest x ray abnormalities. METHODS: A total of 134 dental technicians and 131 non-exposed subjects participated. A medical and an occupational questionnaire were filled in to evaluate the prevalence of respiratory symptoms and occupational exposures. Subjects underwent respiratory tests and chest x ray examination. RESULTS: Mean age of the dental technicians was 36.6 years with a mean duration of dental work of 16.5 years. There was a significant risk of cough (day and night) and usual phlegm in dental technicians. Respiratory function parameters were lower in dental technicians with a significant difference between exposed and non-exposed groups for % FVC (forced vital capacity), % FEF(25) (forced mid expiratory flow), and % FEF(50). The prevalence of small opacities increased with age. Small opacities were significantly related to an exposure to asbestos in the past. CONCLUSIONS: Our young population of dental technicians is at risk of respiratory morbidity. They should benefit from adequate technical prevention measures.

Cancer transmission through corneal transplantation.

PURPOSE: A retrospective study to demonstrate the safety of corneas from donors affected by systemic malignancies in a view of keratoplasty. METHODS: Using the data of the cancer registry department in a district of 500,000 residents, we analyzed retrospectively 143 patients followed up in the same region and transplanted between 1987 and 1995. We compared the incidence of cancer in recipients of cornea coming from donors with malignancies with recipients of cornea from donors without malignancies. The rate of cancer in this population was also compared with the incidence of cancer in the general population at the same age. RESULTS: Eleven patients (7%) were excluded from the study, eight of them for the presence of cancer in their medical history before surgery and the three others because of lack of information about their follow-up after surgery. Forty patients received corneas from cancerous donors and 103 from donors without cancer. Six patients developed malignancies between 1 and 4 years after transplantation, and only one of them received a cornea from a donor with a systemic malignancy. This recipient developed a different type of cancer from that of the donor. The five other patients received corneas from donors without systemic malignancies. By comparing theses results, there was no relationship between the occurrence of malignancies and transplantation of corneas from cancerous donors (relative risk = 0.49, 95% confidence interval = 0.01-13.62). CONCLUSION: There was no increased incidence of cancer in our patient population compared with reference population. Based on this study, there is no statistical or clinical evidence to suggest the transmission of cancer from donors with malignancies via corneal transplantation, according to the accepted criteria of donor selection.

[Evaluation of diagnosis and follow-up in screened children with cystic fibrosis in Normandy]. / Evaluation du diagnostic et du suivi de la cohorte normande d'enfants dépistés atteints de mucoviscidose.

The neonatal screening programme in Normandy (France) allowed the formation of a homogenous cystic fibrosis (CF) cohort of 150 children diagnosed between 1980 and 1997. At the time of this retrospective study, 11 were deceased, out of which nine had meconium ileus (eight deaths after surgery, one at 5 years of age). Sixty children born between 1980 and 1993 in the Basse-Normandie region were followed up during a mean 80 months following similar protocols. The mean age at diagnosis was 41 days (SD = 27 d) for infants without meconium ileus. The occurrence of Pseudomonas aeruginosa (P. aeruginosa) infection and chronic colonization was studied using a monovariate followed by a multivariate analysis including the following variables: sex; meconium ileus; anthropometric data at birth and at diagnosis; pancreatic insufficiency; radiological data (Brasfield score); microbiology data at diagnosis; and genetic data. P. aeruginosa infection appeared earlier in children with pancreatic insufficiency (OR = 2.2; p < 0.05) or with radiological abnormalities (Brasfield score < 21) at diagnosis (OR = 3.9; p < 0.05). Meconium ileus (OR = 5.3; p < 0.01), pancreatic insufficiency (OR = 3.8; p < 0.01) and Brasfield score < 21 at diagnosis (OR = 5.6; p < 0.001) were prognosis factors for early chronic P. aeruginosa colonization. In CF children without meconium ileus, the major risk factor found through multivariate analysis for earlier infection and for earlier chronic colonization by P. aeruginosa was a diagnosis delay > 40 days (respectively OR = 4.6; p < 0.001 and OR = 10.4; p < 0.005). These results must be compared with the lower Brasfield score at diagnosis in infants diagnosed after 40 days of life (p < 0.01).

[Relevance and validity of a new French composite index to measure poverty on a geographical level]. / Pertinence et validité d'un nouvel indice composite français mesurant la pauvreté au niveau géographique.

BACKGROUND: A number of disease conditions are influenced by deprivation. Geographical measurement of deprivation can provide an independent contribution to individual measures by accounting for the social context. Such a geographical approach, based on deprivation indices, is classical in Great Britain but scarcely used in France. The objective of this work was to build and validate an index readily usable in French municipalities and cantons. METHODS: Socioeconomic data (unemployment, occupations, housing specifications, income, etc.) were derived from the 1990 census of municipalities and cantons in the Doubs departement. A new index was built by principal components analysis on the municipality data. The validity of the new index was checked and tested for correlations with British deprivation indices. RESULTS: Principal components analysis on municipality data identified four components (explaining 76% of the variance). Only the first component (CP1 explaining 42% of the variance) was retained. Content validity (wide choice of potential deprivation items, correlation between items and CP1: 0.52 to 0.96) and construct validity (CP1 socially relevant; Cronbach's alpha=0.91; correlation between CP1 and three out of four British indices ranging from 0.73 to 0.88) were sufficient. Analysis on canton data supported that on municipality data. CONCLUSION: The validation of the new index being satisfactory, the user will have to make a choice. The new index, CP1, is closer to the local background and was derived from data from a French departement. It is therefore better adapted to more descriptive approaches such as health care planning. To examine the relationship between deprivation and health with a more etiological approach, the British indices (anteriority, international comparisons) would be more appropriate, but CP1, once validated in various health problem situations, should be most useful for French studies.

Perceived health status in patients over 70 before and after open-heart operations.

AIM: to evaluate improvement and predictors of improvement in patients' perceived health status after cardiac surgery in older patients. METHODS: three hundred and seventy-seven patients from three different departments of cardiac surgery completed the Nottingham Health Profile questionnaire before and 1 and 2 years after open-heart surgery. We analysed pre- and postoperative data and pre- and postoperative Nottingham Health Profile scores. RESULTS: the mean age was 74+/-3 years. The comparison between pre- and postoperative scores showed an improvement in all but the social isolation section. Logistic regression showed that the predictors of patients who became worse after surgery were (i) in the energy section: age over 75 [odds ratio (OR) = 1.8, 95% confidence interval (CI) = 1.02-3.2], coronary artery disease (OR = 2.4, 95% CI = 1.04-3.6) and postoperative events (OR = 1.9, 95% CI = 1.01-3.7); (ii) in the physical mobility section: diabetes mellitus (OR = 2.4, 95% CI = 1.2-4.7); and (iii) in the social isolation section: physical mobility impairment (OR = 3.4, 95% CI = 1.3-8.7). CONCLUSIONS: cardiac surgery improves perceived health status in patients over 70. This improvement is better for those undergoing aortic valve replacement than for those undergoing coronary artery bypass surgery. Comparison with reference scores for a standard population shows that, even when successful, cardiac surgery results in fatigue and persistent sleep disturbance in older patients.

Prospective validation of a diagnosis model as an aid to therapeutic decision-making in acute meningitis.

The aim of this study was to validate a diagnosis model that provides pABM, the probability of bacterial versus viral meningitis, based on four parameters collected at the time of first lumbar tap: cerebrospinal fluid protein level, cerebrospinal fluid polymorphonuclear cell count, blood glucose level, and leucocyte count. The model was evaluated prospectively as an aid to therapeutic decision-making in 109 consecutive patients with acute meningitis and negative cerebrospinal fluid Gram stain. In each case pABM was computed before a therapeutic decision and three diagnoses were established successively: (i) clinical evaluation, i.e. before pABM computation (bacterial meningitis, viral meningitis, or meningitis of undetermined origin); (ii) computation of pABM (viral meningitis if pABM< 0.1, bacterial meningitis otherwise); and (iii) determination of definitive diagnosis (bacterial meningitis: positive cerebrospinal fluid culture; viral meningitis: negative cerebrospinal fluid culture, no other aetiology and no treatment; meningitis of undetermined origin: cases fitting neither of the first two diagnoses). The computed diagnosis was viral meningitis in 78 of the 80 cases diagnosed definitively as viral meningitis, and bacterial meningitis in four of the five cases diagnosed definitively as bacterial meningitis. Negative and positive predictive values and accuracy of the model were 98.7%, 66.7%, and 96.5%, respectively. The clinical diagnosis was undetermined in 22 cases, 15 of which were diagnosed definitively as viral cases; in all of these 15 cases, the computed diagnosis was viral meningitis, leading the physician to refrain from starting antibiotics in all of them. The results confirm that the model evaluated is reliable and aids in the identification of patients in whom antibiotics can be safely avoided.

Disease mapping models: an empirical evaluation. Disease Mapping Collaborative Group.

The analysis of small area disease incidence has now developed to a degree where many methods have been proposed. However, there are few studies of the relative merits of the methods available. While many Bayesian models have been examined with respect to prior sensitivity, it is clear that wider comparisons of methods are largely missing from the literature. In this paper we present some preliminary results concerning the goodness-of-fit of a variety of disease mapping methods to simulated data for disease incidence derived from a range of models. These simulated models cover simple risk gradients to more complex true risk structures, including spatial correlation. The main general results presented here show that the gamma-Poisson exchangeable model and the Besag, York and Mollie (BYM) model are most robust across a range of diverse models. Mixture models are less robust. Non-parametric smoothing methods perform badly in general. Linear Bayes methods display behaviour similar to that of the gamma-Poisson methods.

Soft-tissue sarcoma and non-Hodgkin's lymphoma clusters around a municipal solid waste incinerator with high dioxin emission levels.

Overall evidence from epidemiologic studies in the workplace suggests that dioxin is a human carcinogen, but whether low doses affect the general population remains to be determined. The authors examined the spatial distribution of soft-tissue sarcomas and non-Hodgkin's lymphomas around a French municipal solid waste incinerator with high emission levels of dioxin (16.3 ng international toxic equivalency factor/m3). Not consistently associated with dioxin exposure,-Hodgkin's disease served as the control cancer category. Clusters were identified from 1980 to 1995 in the area ("département') of Doubs by applying a spatial scan statistic to 26 electoral wards. The most likely and highly significant clusters found were identical for soft-tissue sarcomas and non-Hodgkin's lymphomas and included the area around the municipal solid waste incinerator; standardized incidence ratios were 1.44 (observed number of cases = 45, focused test p value = 0.004) and 1.27 (observed number of cases = 286, focused test p value = 0.00003), respectively. Conversely, Hodgkin's disease exhibited no specific spatial distribution. Confounding by socioeconomic status, urbanization, or patterns of medical referral seemed unlikely to explain the clusters. Although consistent, these findings should be confirmed by further investigation (e.g., a case-control study in which dioxins are measured in biologic tissues) before clusters of soft-tissue sarcoma and non-Hodgkin's lymphoma are ascribed to dioxin released by the municipal solid waste incinerator.