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METHODS: Meta-analysis and review of 14 occupational cohort and four case-control studies of workers exposed to trichloroethylene (TCE) to investigate the relation between TCE exposure and the risk of non-Hodgkin's lymphoma (NHL). Studies were selected and categorised based on a priori criteria, and results from random effects meta-analyses are presented. RESULTS: The summary relative risk estimates (SRRE) for the group of cohort studies that had more detailed information on TCE exposure was 1.29 (95% CI 1.00 to 1.66) for the total cohort and 1.59 (95% CI 1.21 to 2.08) for the seven studies that identified a specific TCE exposed sub-cohort. SRREs for three studies with cumulative exposure information were 1.8 (95% CI 0.62 to 5.26) for the lowest exposure category and 1.41 (95% CI 0.61 to 3.23) for the highest category. Comparison of SRREs by levels of TCE exposure did not indicate exposure-response trends. The remaining cohort studies that identified TCE exposure but lacked detailed exposure information had an SRRE of 0.843 (95% CI 0.72 to 0.98). Case-control studies had an SRRE of 1.39 (95% CI 0.62 to 3.10). Statistically significant findings for the Group 1 studies were driven by the results from the subgroup of multiple industry cohort studies (conducted in Europe) (SRRE = 1.86; 95% CI 1.27 to 2.71). The SRRE for single industry cohort studies was not significantly elevated (SRRE = 1.25; 95% CI 0.87 to 1.79). CONCLUSIONS: Interpretation of overall findings is hampered by variability in results across the Group 1 studies, limited exposure assessments, lack of evidence of exposure response trends, lack of supportive information from toxicological and mechanistic data, and absence of consistent findings in epidemiologic studies of exposure and NHL. Although a modest positive association was found in the TCE sub-cohort analysis, a finding attributable to studies that included workers from multiple industries, there is insufficient evidence to suggest a causal link between TCE exposure and NHL.

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AIM: To evaluate the mortality experience of a cohort of employees of a perfluorooctanesulphonyl fluoride (POSF) based fluorochemical production facility. METHODS: A retrospective cohort mortality study followed all workers with at least one year of cumulative employment at the facility. The jobs held by cohort members were assigned to one of three exposure subgroups; high exposed, low exposed, and non-exposed, based on biological monitoring data for perfluorooctane sulphonate (PFOS). RESULTS: A total of 145 deaths were identified in the 2083 cohort members. Sixty five deaths occurred among workers ever employed in high exposed jobs. The overall mortality rates for the cohort and the exposure subcohorts were lower than expected in the general population. Two deaths from liver cancer were observed in the workers with at least one year of high or low exposure (standardised mortality ratio (SMR) 3.08, 95% CI 0.37 to 11.10). The risk of death from bladder cancer was increased for the entire cohort (three observed, SMR 4.81, 95% CI 0.99 to 14.06). All three bladder cancers occurred among workers who held a high exposure job (SMR 12.77, 95% CI 2.63 to 37.35). The bladder cancer cases primarily worked in non-production jobs, including maintenance and incinerator and wastewater treatment plant operations. CONCLUSION: Workers employed in high exposure jobs had an increased number of deaths from bladder cancer; however it is not clear whether these three cases can be attributed to fluorochemical exposure, an unknown bladder carcinogen encountered during the course of maintenance work, and/or non-occupational exposures. With only three observed cases the possibility of a chance finding cannot be ruled out.

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Ammonium perfluorooctanoate is a potent synthetic surfactant used in industrial applications. It rapidly dissociates in biologic media to perfluorooctanoate [CF3(CF2)6CO2-], which is the anion of perfluorooctanoic acid [PFOA, CF3(CF2)6COOH]. PFOA is a peroxisome proliferator known to increase the incidence of hepatic, pancreas and Leydig cell adenomas in rats. The pancreas acinar cell adenomas may be the consequence of a mild but sustained increase of cholecystokinin as a result of hepatic cholestasis. Although no significant clinical hepatic toxicity was observed, PFOA was reported to have modulated hepatic responses to obesity and alcohol consumption among production workers. To further assess these hypotheses, we examined medical surveillance data of male workers involved in ammonium perfluorooctanoate production in 1993 (n=111), 1995 (n=80) and 1997 (n=74). Serum PFOA was measured by high-performance liquid chromatography mass spectrometry methods. Plasma cholecystokinin was measured (only in 1997) by the use of direct radioimmunoassay. Serum biochemical tests included hepatic enzymes, cholesterol and lipoproteins. Serum PFOA levels, by year, were: 1993 (mean 5.0 ppm, SD 12.2, median 1.1 ppm, range 0.0-80.0 ppm); 1995 (mean 6.8 ppm, SD 16.0, median 1.2 ppm, range 0.0-114.1 ppm); and 1997 (mean 6.4 ppm, SD 14.3, median 1.3 ppm, range 0.1-81.3 ppm). Cholecystokinin values (mean 28.5 pg/ml, SD 17.1, median 22.7 pg/ml, range 8.8-86.7 pg/ml) approximated the assay's reference range (up to 80 pg/ml) for a 12 hour fast and were negatively, not positively, associated with employees' serum PFOA levels. Our findings continue to suggest there is no significant clinical hepatic toxicity associated with PFOA levels as measured in this workforce. Unlike a previously reported observation, PFOA did not appear to modulate hepatic responses to either obesity or alcohol consumption. Limitations of these findings include: 1) the cross-sectional design as only 17 subjects were common for the three surveillance years; 2) the voluntary participation that ranged between 50 and 70 percent; and 3) the few subjects with serum levels > or = 10 ppm.

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Safe pesticide handling in a group of Minnesota farmers, aged 40 years and older, was influenced through the use of a multifaceted, countywide educational intervention. Two intervention counties and two control counties were involved in this effort. The intervention consisted of mailed pesticide information to farm households, educational programs on pesticides for county physicians, elementary school training modules on pesticides and the use of safe pesticide handling displays in key business areas by agricultural extension agents. Five hundred eight farmers were identified as pesticide users (186 in the intervention counties and 322 in the control counties). The use of gloves and other protective clothing while handling pesticides increased in the intervention group. Improvement was greater in those who had used protective equipment the least before the intervention. From these results, it appears that a broad-based educational intervention might have a modest impact in how farmers protect themselves when using pesticides.

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The 3M Company manufactures fluorochemicals, which have as a precursor perfluorooctane sulfonyl fluoride (C8F17SO2F). These compounds may be expected to transform metabolically, to an undetermined degree, to perfluorooctane sulfonate (PFOS, C8F17SO3-) as an end-stage metabolite. Subchronic studies in rats and primates indicate a potential for cumulative toxicity with PFOS with the primary effect related to metabolic wasting with hypolipidemia as a consistent finding. Biennial medical surveillance has been offered to the company's fluorochemical production workers located in Decatur, Alabama, and Antwerp, Belgium. In 1995, the mean serum PFOS level, as measured by high-performance liquid chromatography mass spectrometry, for 178 male employees was 2.19 parts per million (ppm; range, 0.00 to 12.83 ppm), and in 1997, for 149 male employees, it was 1.75 ppm (0.10 to 9.93 ppm). Our analyses suggest that among these production employees, there were no substantial changes in serum hepatic enzymes, cholesterol, or lipoproteins associated with PFOS levels less than 6 ppm. It was not possible to derive inferences from the few employees who had serum PFOS levels > or = 6 ppm. These results may be due to the lower levels of serum PFOS measured among these production employees, compared to those suspected to cause effects in laboratory animals.

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Perfluorooctanoic acid (PFOA), a potent synthetic surfactant used in industrial applications, is a peroxisome proliferator that has resulted in dose-related increases in hepatic, pancreatic acinar, and Leydig cell adenomas in laboratory animals. In addition, PFOA increased serum estradiol levels through the induction of hepatic aromatase activity. In 1993 and 1995, we conducted two cross-sectional studies of 111 and 80 production workers, respectively, and specifically measured their serum PFOA in relation to several reproductive hormones to determine whether such an effect occurs in humans. PFOA was not significantly associated with estradiol or testosterone in either year's study. A 10% increase in mean estradiol levels was observed among employees who had the highest levels of serum PFOA, although this association was confounded by body mass index. Neither was PFOA consistently associated with the other measured hormones. Our results provide reasonable assurance that, in this production setting, there were no significant hormonal changes associated with PFOA at the serum levels measured. Limitations of this investigation include its cross-sectional design, the few subjects exposed at the highest levels, and the lower levels of serum PFOA measured, compared with those levels reported to cause effects in laboratory animal studies.

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To assess the effectiveness of a free workplace immunization program at 3M's St. Paul, Minnesota locations, we examined the difference in sick leave hours taken from November 15, 1996, through March 15, 1997, for employees who had and did not have an influenza vaccination prior to the previous year's four-month influenza season (November 15, 1995-March 15, 1996). Among the 2,622 employees who self-reported that they were not immunized in the previous year, there were, on average, 1.2 fewer hours of sick leave taken during the 1996-1997 influenza season than the comparable time period one year earlier (P < 0.05), although the exact reason for the absenteeism was not determined. In particular, we observed that female employees younger than 50 years of age with two or more children took 3.1 hours less sick leave in the year they were immunized, compared with the preceding year (P < 0.0001). Among the 895 subjects who were immunized in both years, employees took 0.7 hours more sick leave during the 1996-1997 influenza season than the previous year (P = 0.46). Based on our findings, consideration should be given to workplace immunization programs. However, we urge caution in applying a "one-size fits all" approach to any cost-savings analysis from a company-sponsored immunization program because the workplace is not a homogeneous [corrected] environment, with regard to employees' age, gender, medical history, and home environment. All of these factors may directly or indirectly contribute to the risk of acquiring influenza and any of its complications.

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Utilization of preventive health care services is lower in rural populations than in urban populations, possibly as a result of barriers to preventive health care that are characteristic of rural settings. This study was conducted to identify factors associated with mammogram utilization among farm women. Mammogram utilization among farm women from six southern Minnesota counties was examined as part of a larger community-based cancer intervention study. Farm women aged 40 and older were randomly selected from a list of farm households and interviewed by telephone to determine mammogram utilization and factors related to utilization. Of the 606 respondents, 78 percent reported ever having a mammogram and 49 percent reported a mammogram within the past year. Physician recommendation for a screening mammogram and family history of breast cancer were found to be associated with ever having a mammogram. Correct knowledge of mammogram screening guidelines was associated with a mammogram within the past 12 months. Overall, physician recommendation was the most influential determinant of utilization. As more emphasis is placed on prevention, patient education by physicians can have the greatest impact on mammogram utilization.

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How farmers protect themselves against pesticide exposure has important public health consequences. To obtain insights into pesticide self-protection, this study obtained data on chemically resistant glove and other protective equipment use as they relate to the type of farming practice, demographic characteristics of farmers and their farming operations, farmers' preventive health beliefs and behaviors, and factors related to their health care. Data were obtained by telephone interviews conducted in six rural Minnesota counties. Survey respondents totaled 1, 327 (87% response rate), with 502 reporting pesticide use. Ninety-five percent of the latter respondents believed in the effectiveness of protective equipment and 88 percent believed that pesticide exposures are harmful. Fifty-six percent of the subjects wore chemically resistant gloves and 22 percent wore other protective clothing 75 percent of the time or more when using pesticides. Glove use and certification to use restricted pesticides was less frequent for women. The use of protective equipment in this group of Minnesota farmers was weakly related to being certified to apply restricted pesticides, believing in the effectiveness of protective clothing, believing that smoking causes serious health problems, using crop insecticides, and distance to a health care facility.

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Proxy respondents have often been used in case-control studies of cancer and pesticides. To evaluate the effect of exposure misclassification, we compared data collected during 1981-1983 from participants interviewed for a case-control study of leukemia and non-Hodgkin's lymphoma with data collected during 1990-1991 from proxy respondents for participants who died or became incompetent since the initial interview (328 self-proxy pairs). As questions increased in detail, agreement percentages decreased. Agreement percentages were highest for demographic and general farming information (averages = 88-90%) and lowest for specific pesticide use (averages = 68-74%). Generally, odds ratios calculated from proxy respondent data were less than those from self-respondent data; however, several exceptions occurred. The findings indicate that pesticide data provided by proxy respondents will not necessarily result in the same estimate of risk and/or lead to the same conclusions as data provided by self-respondents.

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A descriptive study of adolescent work injuries was undertaken using information from Minnesota Department of Labor and Industry workers' compensation files. During the two-year period, 1986-1987, 1,607 work-related injuries were reported in adolescents ages 12 through 17. The largest proportions of injuries occurred in wholesale and retail trade (61.2%), services (24.1%), and manufacturing (5.8%). Injuries most commonly reported were sprains (27.1%), lacerations (26.5%), heat burns (11.4%), and contusions (8.8%). Average annual injury rates were estimated at 14.0/1,000 full-time equivalents for adolescents compared with 24.5/1,000 for adults. The extent of disability or severity of injury could not be determined except that there were no deaths reported during this period.

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This study evaluated the concordance between occupation and industry listed on death certificates with actual work history information for a group (n = 5,882) of long-term (10 years or more) workers at a chemical company. Match rates were calculated as the percent of death certificate occupation and company entries that were confirmed by work history data using 3-digit 1980 U.S. Census Bureau group codes. The concordance rate for industry differed by employment status at death: employed, 94.9%; inactive, 30.8%; and retired, 91.1%. Concordance on occupation was analyzed for employed (n = 467) and retired (n = 932) subjects who had computerized work histories (randomly done prior to the study) and who had matched on the company on the death certificate. Concordance ranged from 0 to 50% for the first job, to 50 to 70% for the last job, longest job, and longest job in the last 10 years of company employment. The most consistent predictor of concordance was job duration. Misclassification was reviewed by occupational category. Results from this and other investigations lead to the inevitable conclusion that usual occupation data from death certificates are grossly inadequate for studies of occupational risks.

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To evaluate the adequacy of preparation for medical practice, we surveyed 320 internal medicine program graduates. The 210 respondents gave their perceptions regarding preparation in training and importance in practice of eight clinical practice skills and 27 clinical procedure skills. The skills with highest preparation scores were venipuncture, intravenous line placement, and arterial puncture for blood gases. The skills rated as the most important in practice were history taking, physical examination, and selection of diagnostic tests. For 13 of the 27 clinical procedure skills, mean preparation scores were significantly higher than mean importance scores, suggesting "overpreparation." In contrast, seven of the eight clinical practice skills had mean preparation scores significantly lower than mean importance scores, suggesting "underpreparation." Furthermore, greater preparation during training was reported by more recent graduates for five of the overprepared skills. We concluded that skills emphasized in internal medicine training are not necessarily those important for practice and that recent changes in the training and practice environments may be increasing these discrepancies.

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Although low back pain (LBP), a major problem for nurses, is presumed to be caused by the physical demands of work, little scientific information supports this view. In this study, registered nurses were surveyed regarding LBP, demographics, medical history, exercise, and work variables. Univariate and multivariate analyses indicated previous LBP or back pain in another location of the spine were strongly associated with LBP during the study year. Aerobic dance exercise was less strongly associated. In contrast, lifting patients was only weakly associated, and other occupational variables not at all. Although results must be interpreted cautiously in light of study limitations, the findings suggest that factors unrelated to work may be more important to LBP than previously thought.

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Pharyngitis is one of the most common clinical problems. Its causes are multiple, two of the best known being streptococcal infection and infectious mononucleosis. Group A beta-hemolytic streptococcal infections are the focus of diagnostic and therapeutic efforts aimed at reducing the risk of both suppurative and nonsuppurative complications. Several non-group A infections are important to recognize as sources of pharyngitis. In addition, mycoplasmal and chlamydial pharyngitis may be more prevalent than is realized. The possibility of gonococcal pharyngitis should be given special attention because of the severity of complications. Recurrent pharyngitis is difficult to manage. Except for certain specific indications, tonsillectomy remains an unproven therapeutic approach.

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