Marie Haring Sweeney

Cancer mortality in workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin

BACKGROUND In both animal and epidemiologic studies, exposure to dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD) has been associated with an increased risk of cancer. METHODS We conducted a retrospective cohort study of mortality among the 5172 workers at 12 plants in the United States that produced chemicals contaminated with TCDD. Occupational exposure was documented by reviewing job descriptions and by measuring TCDD in serum from a sample of 253 workers. Causes of death were taken from death certificates. RESULTS Mortality from several cancers previously associated with TCDD (stomach, liver, and nasal cancers, Hodgkins disease, and non-Hodgkins lymphoma) was not significantly elevated in this cohort. Mortality from soft-tissue sarcoma was increased, but not significantly (4 deaths; standardized mortality ratio [SMR], 338; 95 percent confidence interval, 92 to 865). In the subcohort of 1520 workers with greater than or equal to 1 year of exposure and greater than or equal to 20 years of latency, however, mortality was significantly increased for soft-tissue sarcoma (3 deaths; SMR, 922; 95 percent confidence interval, 190 to 2695) and for cancers of the respiratory system (SMR, 142; 95 percent confidence interval, 103 to 192). Mortality from all cancers combined was slightly but significantly elevated in the overall cohort (SMR, 115; 95 percent confidence interval, 102 to 130) and was higher in the subcohort with greater than or equal to 1 year of exposure and greater than or equal to 20 years of latency (SMR, 146; 95 percent confidence interval, 121 to 176). CONCLUSIONS This study of mortality among workers with occupational exposure to TCDD does not confirm the high relative risks reported for many cancers in previous studies. Conclusions about an increase in the risk of soft-tissue sarcoma are limited by small numbers and misclassification on death certificates. Excess mortality from all cancers combined, cancers of the respiratory tract, and soft-tissue sarcoma may result from exposure to TCDD, although we cannot exclude the possible contribution of factors such as smoking and occupational exposure to other chemicals.

Evaluation of diabetes mellitus, serum glucose, and thyroid function among United States workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

OBJECTIVE: Some studies suggest that exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) may affect glucose metabolism and thyroid function. To further assess the relation between exposure to TCDD and endocrine function, data from the largest morbidity study of industrial workers exposed to TCDD were examined. METHODS: A cross sectional study of workers employed > 15 years earlier in the manufacture of 2,4,5-trichlorophenol or one of its derivatives at two United States chemical plants was conducted. The referent group consisted of people with no occupational exposure to phenoxy herbicides and were recruited from the neighbourhoods where the workers lived. RESULTS: A total of 281 workers and 260 unexposed referents participated. The mean current serum lipid adjusted TCDD concentration among workers was 220 pg/g lipid, and among referents was 7 pg/g lipid (p < 0.05). The half life extrapolated TCDD concentrations (the estimated TCDD concentration when occupational exposure to TCDD stopped) among workers averaged 1900 pg/g lipid (range: not detected--30,000 pg/g lipid). Overall, the prevalence of diabetes mellitus was not significantly different between the workers and referents. Also, there was not a significant positive trend between prevalence of diabetes and increasing serum TCDD concentration. However, diabetes was found in six of 10 (60%) workers with current serum TCDD concentrations > 1500 pg/g lipid. After excluding subjects being treated for diabetes, workers in the group with the highest half life extrapolated TCDD concentrations had a significantly increased adjusted mean serum glucose concentration compared with referents (p = 0.03). Workers were also found to have a significantly higher adjusted mean free thyroxine index compared with referents (p = 0.02), especially among workers in the group with the highest half life extrapolated TCDD concentrations. However, no evidence was found that workers exposed to TCDD were at increased risk of thyroid disease. CONCLUSIONS: These findings provide modest evidence that exposure to TCDD may affect thyroid function and glucose metabolism.

Obesity and other risk factors: The National Survey of U.S. Long-Haul Truck Driver Health and Injury

BACKGROUND Drivers of heavy and tractor-trailer trucks accounted for 56% of all production and nonsupervisory employees in the truck transportation industry in 2011. There are limited data for illness and injury in long-haul truck drivers, which prompted a targeted national survey. METHODS Interviewers collected data during 2010 from 1,670 long-haul truck drivers at 32 truck stops across the 48 contiguous United States that were used to compute prevalence estimates for self-reported health conditions and risk factors. RESULTS Obesity (69% vs. 31%, P < 0.01) and current smoking (51% vs. 19%, P < 0.01) were twice as prevalent in long-haul truck drivers as in the 2010 U.S. adult working population. Sixty-one percent reported having two or more of the risk factors: hypertension, obesity, smoking, high cholesterol, no physical activity, 6 or fewer hours of sleep per 24-hr period. CONCLUSION Survey findings suggest a need for targeted interventions and continued surveillance for long-haul truck drivers.

Review and update of the results of the NIOSH medical study of workers exposed to chemicals contaminated with 2,3,7,8‐tetrachlorodibenzodioxin

In 1987, the National Institute for Occupational Safety and Health conducted a cross-sectional medical study to examine the long-term health effects of occupational exposure to chemicals and materials contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). This study compared living workers employed more than 15 years earlier in the production of sodium trichlorophenol (NaTCP), and 2,4,5-trichlorophenoxyacetic ester (2,4,5-T ester) with an unexposed comparison group. Health status of the worker and comparison populations was collected through a comprehensive set of standardized interviews and medical examinations. Lipid adjusted serum TCDD levels were also measured. Workers had a statistically significantly elevated mean serum lipid-adjusted TCDD level (workers = 220 pg per g of lipid [range = not detected-3,400 pg per g of lipid], and referents 7 pg per g of lipid [range not detected-20 pg per g of lipid], P < 0.001). Compared to a community-based referent population, the prevalence of chronic bronchitis, chronic obstructive pulmonary disease, peripheral neuropathy, depression, cardiovascular outcomes (myocardial infarction, angina, cardiac arrhythmias, hypertension, and abnormal peripheral arterial flow), abnormal porphyrin levels, and abnormal ventilatory function parameters FEV1.0, FVC, or FEV1.0/FVC% in workers, was not statistically significantly different. In contrast, relationships were observed between serum 2,3,7,8-TCDD levels and the enzyme gamma-glutamyltransferase (GGT), the reproductive hormones serum testosterone, luteinizing, and follicle-stimulating hormones, and abnormal high-density lipoprotein concentration, counts of CD3/Ta1 cells (helper lymphocytes), and fasting serum glucose levels. Current diagnosis of chloracne was associated with the highest levels of serum 2,3,7,8-TCDD. Analysis of other endpoints continues.

Prevalence and work-relatedness of carpal tunnel syndrome in the working population, United States, 2010 National Health Interview Survey.

BACKGROUND Patterns of prevalence and work-relatedness of carpal tunnel syndrome (CTS) among workers offer clues about risk factors and targets for prevention. METHODS Data from an occupational health supplement to the 2010 National Health Interview Survey were used to estimate the prevalence of self-reported clinician-diagnosed CTS overall and by demographic characteristics. The proportion of these cases self-reported to have been attributed to work by clinicians was also examined overall and by demographic characteristics. In addition, the distribution of industry and occupation (I&O) categories to which work-related cases of CTS were attributed was compared to the distribution of I&O categories of employment among current/recent workers. RESULTS Data were available for 27,157 adults, including 17,524 current/recent workers. The overall lifetime prevalence of clinician-diagnosed CTS among current/recent workers was 6.7%. The 12-month prevalence was 3.1%, representing approximately 4.8 million workers with current CTS; 67.1% of these cases were attributed to work by clinicians, with overrepresentation of certain I&O categories. CONCLUSIONS CTS affected almost 5 million U.S. workers in 2010, with prevalence varying by demographic characteristics and I&O.

Evaluation of serum lipid concentrations among U.S. workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

2,3,7,8-Tetrachlorodibenzo-p-dioxin alters lipid metabolism in animals; however, evidence for such an effect in humans is conflicting. This conflict was addressed using data from a cross-sectional medical study conducted between 1987 and 1988. The exposed participants had been employed at least 15 y earlier in the manufacture of 2,4,5-trichlorophenol or one of its derivatives at two chemical plants in the United States. A total of 281 workers and 260 unexposed referents participated. Workers had substantial exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin, evidenced by a median serum 2,3,7,8-tetrachlorodibenzo-p-dioxin concentration of 406.6 femtograms/gram of serum (fg/g serum), compared with 36.9 fg/g serum among the referents. A slight association between triglyceride concentration and serum 2,3,7,8-tetrachlorodibenzo-p-dioxin concentration was found (p = .05). Over the range of observed 2,3,7,8-tetrachlorodibenzo-p-dioxin values (i.e., 37-19000 fg/g serum), triglyceride concentration increased only about 0.4 mmol/I. No association was found between an abnormally elevated triglyceride (i.e., > 2.82 mmol/I) concentration and serum 2,3,7,8-tetrachlorodibenzo-p-dioxin concentration. An association was also found between serum 2,3,7,8-tetrachlorodibenzo-p-dioxin concentration and an abnormal high-density lipoprotein concentration (p = .09). in summary, there was evidence of an effect on lipid metabolism in a group of workers with high serum 2,3,7,8-tetrachlorodibenzo-p-dioxin concentrations. The influence of serum 2,3,7,8-tetrachlorodibenzo-p-dioxin on lipid concentrations, however, was small, compared with the influence of other factors.

Adherence to Safe Handling Guidelines by Health Care Workers Who Administer Antineoplastic Drugs

The toxicity of antineoplastic drugs is well documented. Many are known or suspected human carcinogens where no safe exposure level exists. Authoritative guidelines developed by professional practice organizations and federal agencies for the safe handling of these hazardous drugs have been available for nearly three decades. As a means of evaluating the extent of use of primary prevention practices such as engineering, administrative and work practice controls, personal protective equipment (PPE), and barriers to using PPE, the National Institute for Safety and Health (NIOSH) conducted a web survey of health care workers in 2011. The study population primarily included members of professional practice organizations representing health care occupations which routinely use or come in contact with selected chemical agents. All respondents who indicated that they administered antineoplastic drugs in the past week were eligible to complete a hazard module addressing self-reported health and safety practices on this topic. Most (98%) of the 2069 respondents of this module were nurses. Working primarily in hospitals, outpatient care centers, and physician offices, respondents reported that they had collectively administered over 90 specific antineoplastic drugs in the past week, with carboplatin, cyclophosphamide, and paclitaxel the most common. Examples of activities which increase exposure risk, expressed as percent of respondents, included: failure to wear nonabsorbent gown with closed front and tight cuffs (42%); intravenous (I.V.) tubing primed with antineoplastic drug by respondent (6%) or by pharmacy (12%); potentially contaminated clothing taken home (12%); spill or leak of antineoplastic drug during administration (12%); failure to wear chemotherapy gloves (12%); and lack of hazard awareness training (4%). The most common reason for not wearing gloves or gowns was “skin exposure was minimal”; 4% of respondents, however, reported skin contact during handling and administration. Despite the longstanding availability of safe handling guidance, recommended practices are not always followed, underscoring the importance of training and education for employers and workers.

A retrospective job exposure matrix for estimating exposure to 2,3,7, 8-tetrachlorodibenzo-p-dioxin.

BACKGROUND A job exposure matrix was developed to estimate the 2,3, 7,8-tetrachlorodibenzo-p-dioxin exposure of 3,538 workers who produced 2,4,5-trichlorophenol and its derivatives. METHODS Daily TCDD exposure scores that were plant, process, and period specific were estimated for each job title as the product of 1) the concentration of TCDD (microg/g); 2) a qualitative factor to account for the extent of worker contact and 3) time exposed to TCDD contamination. Daily scores were summed to compute individual cumulative TCDD exposure scores. RESULTS Daily TCDD exposure scores ranged from 0.001 to 1,250. Cumulative TCDD scores ranged from 0.002 to 1,559,430. The 393 workers with records of chloracne in the TCDD exposure cohort (11%) had markedly higher cumulative scores than those with no record of chloracne (a median score of 11,546 vs. 77). CONCLUSIONS The cumulative TCDD exposure scores incorporate both duration and level of exposure, and permit the relative ranking of worker exposures for the evaluation of exposure-response relationships between TCDD exposure and mortality in an updated cohort study analysis.

Tradeswomen's perspectives on occupational health and safety : A qualitative investigation

Qualitative research methods were used to determine the health and safety concerns of women employed in the construction trades. Major categories of concern were identified, including: 1) exposure to chemical and physical agents; 2) injuries from lifting/bending/ twisting, falling, and lacerations; 3) lack of proper education and training; and 4) the health and safety risks related specifically to tradeswomen. Many of the issues identified by the workers are amenable to change through either engineering, behavioral, or administrative interventions.

Immunological markers among workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

OBJECTIVES: To examine the association of immune cell number and function with occupational exposure to substances contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). METHODS: A cross sectional medical survey. The exposed participants were employed at two chemical plants between 1951 and 1972 in the manufacture of 2,4,5-trichlorophenate and its derivatives. The reference group consisted of people with no occupational exposure to phenoxy herbicides who lived within the communities of the workers. Data from a total of 259 workers and 243 unexposed referents were included in the analysis of immune function. Laboratory tests for immune status included enumeration of circulating leukocyte and lymphocyte populations, proliferative responses of circulating lymphocytes to mitogens and antigens, and serum concentrations of the major immunoglobulins and complement factor C3. RESULTS: The workers had substantial exposure to substances contaminated with TCDD, as indicated by a lipid adjusted mean serum TCDD concentration of 229 ppt compared with a mean of 6 ppt in the unexposed referents. Workers were divided into categories based on their serum TCDD concentration. For all categories except the lowest, with values of serum TCDD comparable with the unexposed referents, there were increased odds of having lower counts of CD26 cells (activated T cells) (odds ratio (OR) 1.0, 95% confidence interval (95% CI) 0.5 to 1.8 for TCDD < 20 ppt; OR 1.6, 95% CI 0.8 to 3.2 for TCDD 20-51 ppt; OR 2.7, 95% CI 1.4 to 5.1 for TCDD 52-125 ppt; OR 2.6, 95% CI 1.4 to 4.9 for TCDD 125-297 ppt; OR 2.4, 95% CI 1.3 to 4.6 for TCDD 298-3389 ppt). A less consistent finding was decreased spontaneous proliferation of cultured lymphocytes. However, increases were found in proliferation of lymphocytes in response to concanavalin and pokeweed in workers in the high TCDD category. Age, cigarette smoking, and alcohol were significant predictors of several immunological outcomes. CONCLUSIONS: Associations between serum TCDD concentration and both a decrease in circulating CD26 cells and decreased spontaneous background proliferation were the major findings of this study. These results are unlikely to be of clinical importance but may reflect limited evidence for an association between immunological changes in workers and high serum concentrations of TCDD, or chance findings resulting from the evaluation of multiple immunological variables.