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Oral Session 13 – Acute/chronic effects

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O13.1 ACUTE SYMPTOMS FOLLOWING PESTICIDE EXPOSURE

C. Solomon, J. Poole, K. Palmer, D. Coggon.MRC Environmental Epidemiology Unit, University of Southampton, Southampton, UK

Introduction: In Britain, despite tight regulation on use of pesticides, anecdotal reports of symptoms following their use are not uncommon. However, it is unclear how frequently such illness occurs, and to what extent it is a manifestation of acute toxicity. To address this question, we analysed data from a community based postal survey of work and health among men aged 25–69 years in three rural regions of England and Wales.

Methods: Data were available for 10 697 (33%) of the men eligible for study. Among other things, these covered occupational use of sheep dip, insecticides, herbicides, fungicides, and wood preservatives; the occurrence of each of 12 symptoms within 48 hours of using each class of pesticide; and the extent to which the subject had been bothered by seven diverse somatic symptoms in the past week (taken as an index of somatising tendency). Analysis focused on the 4109 men who indicated that they had at some time used pesticides occupationally.

Results: Altogether, 936 men (23%) reported at least one symptom within 48 hours of using a pesticide. The relative frequency of different symptoms was similar for each class of pesticide, as was a tendency for clustering of multiple symptoms. In two regions, including one where there had been much local publicity about possible adverse effects of sheep dips, all symptoms were markedly more common in relation to dipping of sheep (31% of users compared with 6–11% following the use of other pesticides). In the third region, symptoms in relation to sheep dip were less common (13%) than following the use of insecticides (15%). Report of symptoms in relation to multiple classes of pesticide was much more frequent than would be expected from the prevalence of symptoms associated with each class individually (105 observed v 1.8 expected for 3+ classes). Report of multiple symptoms following pesticide use was strongly associated with a tendency to somatise (odds ratio 7.0, 95% confidence interval 4.1 to 12.1).

Conclusions: These findings confirm that acute symptoms are common following the use of pesticides. However, the similarity of symptom patterns for each pesticide class, the marked regional difference in the prevalence of symptoms associated with sheep dip, and the strong association of symptoms with tendency to somatise suggest that in many cases the illness reported is not a consequence of direct toxicity.

O13.2 HEALTH STATUS AND PLASMA DIOXIN LEVELS IN CHLORACNE CASES 20 YEARS AFTER THE ACCIDENT IN SEVESO, ITALY

A. C. Pesatori1, A. Baccarelli12, D. Consonni1, P. Mocarelli3, D. G. Patterson Jr4, N. E. Caporaso*, P. A. Bertazzi1, M. T. Landi2.1Department of Occupational and Environmental Health, University of Milan, Milan, Italy; 2Genetic Epidemiology Branch, DCEG, NCI/NIH/DHHS, Bethesda, MD, USA; 3University of Milan-Bicocca, Desio, Italy; 4Centers for Disease Control and Prevention, Atlanta, GA, USA

Introduction: In 1976, an accident at a chemical plant in Seveso, Italy exposed a large population to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The accident resulted, mostly among children, in one of the largest ever reported outbreaks of chloracne, the typical skin disorder caused by halogenated hydrocarbon compounds. Approximately 20 years after the accident, we conducted an epidemiological study in Seveso to investigate (a) the health status of chloracne cases; (b) the TCDD–chloracne exposure–response relationship; and (c) factors modifying TCDD toxicity.

Methods: From 1993 to 1998, we recruited 101 chloracne cases and 211 controls. Trained interviewers administered a structured questionnaire assessing, among other epidemiological variables, information on an extensive list of diseases. Individual pigmentary characteristics were determined. We measured plasma TCDD levels using high resolution gas chromatography and mass spectrometry.

Results: Plasma TCDD was still elevated (>10 ppt) in 78 (26.6%) of the 293 subjects with adequate plasma samples, particularly in females, in subjects who had eaten home raised animals, and in older individuals, those with higher body mass index, and those who resided near the accident site. After 20 years, the health conditions of chloracne cases were similar to those of controls from the Seveso area. Elevated plasma TCDD was associated with chloracne (odds ratio 3.7; 95% confidence interval 1.6 to 8.8, adjusted for age, gender, and residence). Chloracne risk was higher in subjects younger than 8 years at the accident (7.4; 1.8 to 30.3) and, contrary to previous hypotheses, did not increase at puberty onset or in teenage years. Subjects with elevated TCDD levels and light hair colour had higher relative odds of chloracne (9.2; 2.6 to 32.5).

Conclusions: Dioxin toxicity in chloracne cases was confined to the acute dermatotoxic effects. Chloracne occurrence appeared related to younger age and light hair colour. Age related dioxin elimination or dilution must be taken into account in interpreting these results.

O13.3 STUDY OF IMMUNE EFFECTS IN CORN FARMERS

R. Vermeulen1, A. J. De Roos2, A. Blair1, A. Hildesheim1, L. Pinto3, P. P. Gillette4, C. F. Lynch4, R. H. Allen5, M. C. Alavanja1.1Division of Cancer Epidemiology and Genetics, NCI, Rockville, USA; 2Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, USA; 3HPV Monitoring Laboratory, NCI, Frederick, USA; 4College of Public Health, University of Iowa, Iowa City, USA; 5Environmental Protection Agency, Washington, USA

Introduction: Compared with the general population, farmers have an increased risk of non-Hodgkin’s lymphoma (NHL). It has been hypothesised that altered immune function may be an indicator of increased potential for the development of immunologically based diseases such as NHL.

Objective: To investigate changes in immune function in corn farmers in relation to farming activities and pesticide exposures.

Methods: We selected 30 corn farmers and 10 agricultural extension workers in Iowa, aged 40–60 years, who were non-smoking males. Farmers and controls were visited six times during the year, coinciding with critical periods in the growing season (before, during, and after planting; before and after harvest; off season). Blood and urine specimens were collected at each visit, and detailed information about farming, pesticide use, and recreational activities were recorded during the entire year. Exposure to selected pesticides (such as atrazine, 2,4-D, and organophosphates) was assessed though quantification of their respective urinary metabolites in combination with questionnaire information. Immune status was investigated by measurement of lymphocyte subsets and activation markers, circulating cytokines and immunoglobulins, and by performing lymphoproliferation assays to mitogen and recall antigens in vitro.

Results: All scheduled farm visits were successfully completed and 100% of blood/urine specimens were collected and processed. Baseline information on available biological measures indicates an overall healthy population, as values are generally within the normal range.

Conclusions: The detailed exposure information, the longitudinal design, and extensive battery of assays to quantify immune status will provide a valuable opportunity to study the possible relation between farming, pesticide exposure, and potential immune perturbations. At the meeting we plan to present results on lymphocyte subsets and activation markers in relation to farming activities and pesticide exposures.

O13.4 CHRONIC BENZENE POISONING AND PERIODONTAL DISEASE

M. M. A. Brandão1, S. M. Freire1, M. A. V. Rêgo2.1D Immunology Service, Science Health Institute, Federal University of Bahia; 2Department of Preventive Medicine, School of Medicine, Federal University of Bahia, Brazil

Introduction: Lifetime exposure to benzene is associated to a variety of blood disorders, and except for the risk of cancer, almost nothing is known about the health impairments in individuals who had left the exposure. In Brazil this exposure is a serious problem in the workplace, and many workers have already been rendered unable to work due to this intoxication, including those in the area of the study, the state of Bahia, the largest producer of benzene in Latin America. From a larger study to describe health effects and genetic polymorphisms among workers with chronic benzene poisoning (CBP), this specific investigation analysed the association between periodontal disease and CBP, and describes the pattern of subpopulations of leukocytes.

Methods: A case–control study was performed with 24 cases of CBP and 24 controls with other occupational diseases, selected at the Workers Health Center (CESAT) in the state of Bahia, Brazil. Clinical and epidemiological variables were collected from medical records and from a detailed questionnaire. A detailed oral examination was performed by a dentist specialised in periodonty.

Results: Cases and controls were similar regarding mean age (50.2 and 51.4 years, respectively). CBP and periodontal disease were positively associated (odds ratio 3.78; 95% CI 2.4 to 7.0, adjusted for smoking).

Conclusions: These results should be taken with caution because of the low numbers, but they do point to a suspicion that former benzene workers have impairments of the immune system, which can contribute to a carcinogenesis process. These workers must be rigorously followed in a programme of medical surveillance. Although the magnitude of this problem has been known for many years, this is the first attempt to describe these effects in Brazil and further investigations should be carried out.

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