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Biomedical subjects

T M Schnorr

Publications and source records attributed to T M Schnorr.

At least 19 recordsLinked to original sources
PubMed2004

Bacillus anthracis contamination and inhalational anthrax in a mail processing and distribution center.

AIMS: Four inhalational anthrax cases occurred in a large mail processing and distribution center in Washington, DC, after envelopes containing Bacillus anthracis spores were processed. This report describes the results of sampling for B. anthracis spores during investigations conducted in October and December 2001. METHODS AND RESULTS: Wet swabs, wet wipes, vacuum sock, and air-filter samples were collected throughout the facility to characterize the extent of building contamination. The results showed widespread contamination of B. anthracis spores, particularly associated with one delivery bar code sorter (DBCS) machine that had sorted the spore-containing envelopes and an area where the envelopes were handled by postal workers. Spore concentrations decreased as distance from the DBCS machine increased, but spores were widely dispersed into surrounding areas. CONCLUSION: The spatial distribution of culture positive samples was closely related to the work areas of the inhalational anthrax cases and supported epidemiological evidence that the workers became ill from exposure to B. anthracis spores in areas where the contaminated envelopes had travelled. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this investigation were used to guide decontamination efforts and provided baseline spore concentrations for follow-up measurements after the building had been cleaned. Implementing methods to reduce aerosolization and dispersion of dust within the facility would reduce postal workers' potential exposures to bioterrorism agents.

Air Pollution, Indoor↗
PubMed2003

Prevalence of respiratory symptoms among female flight attendants and teachers.

BACKGROUND: Potential health effects of the indoor environment in office buildings and aircraft have generated considerable concern in recent years. AIMS: To analyse the prevalence of self reported respiratory symptoms and illnesses in flight attendants (FAs) and schoolteachers. METHODS: Data were collected as part of a study of reproductive health among female FAs. The prevalences of work related eye, nose, and throat symptoms, wheezing, physician diagnosed asthma, chest illness, and cold or flu were calculated and stratified by smoking status in 1824 FAs and 331 schoolteachers. RESULTS: FAs and teachers were significantly more likely to report work related eye (12.4% and 7.4 %, respectively), nose (15.7% and 8.1%), and throat symptoms (7.5% and 5.7%) than were other working women (2.9% eye, 2.7% nose, and 1.3% throat symptoms). FAs were significantly more likely than teachers and referent working women to report chest illness during the prior three years (32.9%, 19.3%, 7.2%, respectively). Both study groups were more likely to report five or more episodes of cold or flu in the past year than were other working women (10.2% of FAs, 8.2% of teachers, 2.3% of referents), and both groups were more likely to report wheezing than other working women (22.8% of FAs, 28.4% of teachers, 16.4% of referents). FAs were significantly less likely than teachers and other working women to report ever having been diagnosed with asthma (8.2%, 13.3%, 11.8%, respectively). CONCLUSIONS: Overall, FAs and schoolteachers report a higher prevalence of work related upper respiratory symptoms, chest illness, and cold or flu than the general working population.

Adult↗
PubMed2001

Spontaneous abortion, sex ratio, and paternal occupational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

There is conflicting research regarding an association between fetal death and paternal exposure to Agent Orange, a phenoxy herbicide widely used in Vietnam that was contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Men who worked in the U.S. factories that produced Agent Orange were exposed to TCDD at levels hundreds of times higher than TCDD levels in the general population. Wives of TCDD-exposed chemical workers and wives of nonexposed neighborhood referents were interviewed to determine reproductive history. Paternal serum TCDD level at time of conception was estimated for each pregnancy using serum samples taken in 1987. Estimated TCDD levels of workers during or after exposure were high (median, 254 ppt; range, 3-16,340 ppt) compared to referent levels (median, 6 ppt; range, 2-19 ppt). No association between paternal TCDD level at the time of conception and spontaneous abortion was observed among pregnancies fathered by workers with TCDD levels of < 20 ppt [odds ratio (OR) = 0.77; 95% confidence interval (CI), 0.48-1.22], 20 to < 255 ppt (OR = 0.81; 95% CI, 0.40-1.63), 255 to < 1,120, (OR = 0.69; 95% CI, 0.30-1.58), and >or= 1,120 ppt (OR = 0.95; 95% CI, 0.42-2.17) compared to pregnancies fathered by referents. The sex ratio [males/(males + females)] of offspring also did not differ by TCDD exposure (0.53 and 0.54 among workers and referents, respectively). We did not find an association between paternal serum TCDD level and spontaneous abortion or sex ratio of offspring in this population. The estimated TCDD levels in this exposed worker population were much higher than in other studies, providing additional evidence that paternal TCDD exposure does not increase the risk of spontaneous abortion at levels above those observed in the general population. The study could not evaluate the effect of father's childhood or prenatal TCDD exposure on subsequent sex ratio.

Abortion, Spontaneous↗
PubMed1998

Cancer risks among workers exposed to metalworking fluids: a systematic review.

Metalworking fluids (MWFs) are commonly used in a variety of industrial machining and grinding operations. The National Institute for Occupational Safety and Health (NIOSH) estimates that more that one million workers are exposed to MWFs. NIOSH conducted a comprehensive and systematic review of the epidemiologic studies that examined the association between MWF exposure and cancer. Substantial evidence was found for an increased risk of cancer at several sites (larynx, rectum, pancreas, skin, scrotum, and bladder) associated with at least some MWFs used prior to the mid-1970s. This paper provides the evidence pertaining to cancer at these sites. Cancer at those sites found to have more limited or less consistent evidence for an association with MWF (stomach, esophagus, lung, prostate, brain, colon, and hematopoietic system) will not be discussed in this paper but are discussed in the recent NIOSH Criteria for a Recommended Standard-Occupational Exposure to MWFs. Because the changes in MWF composition that have occurred over the last several decades may not be sufficient to eliminate the cancer risks associated with MWF exposure, reductions in airborne MWF exposures are recommended.

Air Pollutants, Occupational↗
PubMed1998

Immunologic findings among lead-exposed workers.

A comprehensive panel of immune parameters was evaluated among 145 lead-exposed workers with a median blood lead level (BLL) of 39 micrograms/dL (range: 15-55 micrograms/dL) and 84 unexposed workers. After adjusting for covariates, we found no major differences in the percentage of CD3+ cells, CD4+ T cells, CD8+ T cells, B cells, or NK cells between lead-exposed and unexposed workers, although the association between lead exposure and the number of CD4+ T cells was modified by age. We also found no differences between exposed and unexposed workers in serum immunoglobulin levels, salivary IgA, C3 complement levels, or lymphoproliferative responses. However, among exposed workers, the percentage and number of B cells were positively associated with current BLL, serum IgG was negatively associated with cumulative lead exposure, and the percentage and number of CD4+/CD45RA+ cells were positively associated with cumulative lead exposure. We found no evidence of a marked immunotoxic effect of lead at the exposure levels studied, although some subtle differences in immunologic parameters were noted.

Adult↗
PubMed1997

Work with video display terminals and the risk of reduced birthweight and preterm birth.

To determine whether the use of video display terminals (VDTs) is associated with an increased risk of reduced birthweight (RBW) and preterm birth, a cohort of telephone operators who used VDTs at work was compared to a cohort of non-VDT-users. Among 2,430 women interviewed, 713 eligible singleton live births were reported. Exposure was estimated from company records and a representative sample of electromagnetic fields was measured at the VDT workstations. For RBW (< or = 2,800 g), we found no excess risk associated with any VDT use during pregnancy (odds ratio [OR] = 0.9; 95% confidence interval [CI] = 0.5-1.7). For preterm birth (< or = 37 weeks), we similarly found no excess risk (OR = 0.7; 95% CI = 0.4-1.1). The risks estimated did not change substantially when hours working with VDTs were used as exposure variables. By contrast, increased risks were found for several known risk factors for LBW and preterm birth. We conclude that occupational VDT use does not increase the risk of RBW and preterm birth.

Adult↗
PubMed1997

Identifying deaths before 1979 using the Social Security Administration Death Master File.

For cohort studies, the Social Security Administration (SSA) traditionally has been the principal source of deaths that occurred before 1979. In 1988, the SSA abolished a system that provided a relatively complete accounting of deaths and replaced it with the Death Master File. We examined the completeness of the SSA Death Master File by comparing it with the U.S. Vital Statistics records and by searching the SSA Death Master File for known decedents from seven cohorts. Overall, only 53% of reported U.S. deaths and 75% of known deaths in our seven cohorts were included in the SSA Death Master File. Ascertainment was better after 1975 (89-95%). A re-analysis of two cohorts that excluded deaths before 1979 not found in the SSA Death Master File resulted in 20-35% decreases in both standardized mortality ratios and dose-response trends. Although the SSA system before 1988 provided relatively complete vital status information, the SSA Death Master File is inadequate for vital status determination. New cohorts with a substantial number of deaths before the inception of the National Death Index in 1979 will be most seriously affected.

Cohort Studies↗
PubMed1997

Elevated blood lead levels in children of construction workers.

OBJECTIVES: This study examined whether children of lead-exposed construction workers had higher blood lead levels than neighborhood control children. METHODS: Twenty-nine construction workers were identified from the New Jersey Adult Blood Lead Epidemiology and Surveillance (ABLES) registry. Eighteen control families were referred by workers. Venous blood samples were collected from 50 children (31 exposed, 19 control subjects) under age 6. RESULTS: Twenty-six percent of workers children had blood lead levels at or over the Centers for Disease Control and Prevention action level of 0.48 mumol/L (10 micrograms/dL), compared with 5% of control children (unadjusted odds ratio = 6.1; 95% confidence interval = 0.9, 147.2). CONCLUSIONS: Children of construction workers may be at risk for excessive lead exposure. Health care providers should assess parental occupation as a possible pathway for lead exposure of young children.

Adult↗
PubMed1996

Evaluation of reproductive function among men occupationally exposed to a stilbene derivative: I. Hormonal and physical status.

This is the first of two reports describing a National Institute for Occupational Safety and Health (NIOSH) Health Hazard Evaluation conducted in response to complaints of impotence and decreased libido among male employees who manufactured 4,4'-diaminostilbene-2,2' disulfonic acid (DAS; CAS 81-11-8), an intermediate in the manufacture of fluorescent whitening agents. DAS is structurally similar to the synthetic estrogen diethylstilbestrol (DES). Levels of six reproductive hormones in 30 male workers who manufactured DAS (current DAS workers) and 20 former DAS workers were compared to levels of 35 workers who manufactured plastics additives. Current and former DAS workers had lower mean total testosterone (TT) levels compared to additives workers (458 and 442, respectively, vs. 556 ng/dL; p = 0.05 and 0.04). Current and former DAS workers were 3.6 (95% CI, 0.5-24.4) and 2.2 (95% CI, 0.3-18.0) times more likely than additives workers to have lowest quartile TT levels (< 386 ng/dL) after adjustment for age and body mass index. Duration of employment in DAS production was negatively related to the workers' testosterone levels. These data suggest that occupational DAS exposure may be associated with alterations in male reproductive hormone levels.

Adult↗
PubMed1996

Evaluation of reproductive function among men occupationally exposed to a stilbene derivative: II. Perceived libido and potency.

This is the second of two reports of a National Institute for Occupational Safety and Health (NIOSH) Health Hazard Evaluation conducted in response to complaints of sexual dysfunction among men who manufacture the stilbene derivative 4,4'-diaminostilbene-2,2'-disulfonic acid (DAS; CAS 81-11-8), an intermediate in the manufacture of fluorescent whitening agents. The first report [Grajewski et al. (1995): Am J Ind Med 29:53-61] describes results of the analysis of reproductive hormone levels. This second report provides results from the analysis of perceived libido and potency. In a cross-sectional design, self-reported sexual function of 30 male workers who manufacture DAS and 20 former DAS workers was compared to that of 35 workers who manufactured plastics additives in a different manufacturing area. Questionnaire items were examined by factor analysis, reducing the data to these components of sexual function: sexual activity/performance (two factors), interest, satisfaction, and physiologic competence. Adjusting for age, currently exposed workers were more likely than unexposed workers to have a value in the lowest quartile for interest (adjusted odds ratio [OR] = 1.9, 95% confidence interval [CI] 0.5-7.2), physiologic competence (adjusted OR = 1.9, 95% CI 0.6-6.4), and activity/performance factor II (adjusted OR = 5.8, 95% CI 1.3-27.3). Former DAS workers reported problems associated with activity/performance factors I and II compared to unexposed workers (adjusted OR = 2.2, 95% CI 0.5-10.1 and adjusted OR = 6.7, 95% CI 1.2-35.9, respectively). Although the small study size limits the precision of the effect estimates, the pattern of results suggests a possible effect on sexual function of working in the DAS manufacturing area.

Cross-Sectional Studies↗
PubMed1996

Mortality of workers exposed to toluene diisocyanate in the polyurethane foam industry.

OBJECTIVE: To evaluate cancer mortality among United States workers exposed to toluene diisocyanate (TDI) in the manufacture of polyurethane foam. METHODS: This cohort mortality study included 4611 men and women employed in four polyurethane foam plants for at least three months between the late 1950s and 1987. The mortality experience of the cohort was then compared with that of the general United States population. RESULTS: Current and past industrial hygiene data indicated that air concentrations in 1984-5 were below the current United States standard of 0.04 mg/m3 but exceeded the standard before 1980. Mortality ratio (SMR) 2.78, 95% confidence interval (95% CI) 0.57-8.13) and non-Hodgkin's lymphoma (SMR 1.54, 95% CI 0.42-3.95) were increased, but not significantly. There was one male breast cancer. However, breast cancer was not increased in women (SMR 0.74). No other cancer category had an increased number of deaths compared with the general population. Only non-Hodgkin's lymphoma and Hodgkin's disease showed a possible relation with time since first employment and no cancer death category showed a strong relation with duration of employment. Mortality from non-malignant respiratory disease was not increased (SMR 0.86). CONCLUSIONS: This young cohort has few deaths and short follow up. The findings are therefore not conclusive. Further years of follow up will enable better evaluation of mortality.

Air Pollutants, Occupational↗
PubMed1995

Mortality in a cohort of antimony smelter workers.

Animal studies show that antimony may cause lung cancer and heart and lung disease in rodents. In exposed humans, ECG abnormalities and heart and lung disease have been reported. This mortality study of 1,014 men employed between 1937 and 1971 in a Texas antimony smelter consisted primarily of workers of Spanish ancestry (n = 928, 91.5%). Hispanics are known to smoke at much lower rates than non-Hispanics, and their lung cancer and heart disease mortality is generally low. When ethnic-specific Texas lung cancer death rates were used for comparison, mortality from lung cancer among antimony workers was elevated (SMR) 1.39, 90% CI 1.01-1.88), and we observed a significant positive trend in mortality with increasing duration of employment. When ischemic heart disease death rates from three different Spanish-surnamed populations were used for comparison, the rate ratios for mortality from ischemic heart disease were 0.91 (90% CI 0.84-1.09), 1.22 (90% CI 0.78-1.89), and 1.49 (90% CI 0.84-2.63). Pneumoconiosis/ other lung disease death rates for Spanish-surnamed men were unavailable and so calculation of rate ratios used white males as a comparison population (SMR 1.22; 90% CI 0.80-1.80). These data suggest some increased mortality from lung cancer and perhaps nonmalignant respiratory heart disease in workers exposed to antimony. However, conclusions are limited by possible confounders and the difficulty of identifying appropriate referent groups.

Adult↗
PubMed1995

Mortality among Navajo uranium miners.

OBJECTIVES: To update mortality risks for Navajo uranium miners, a retrospective cohort mortality study was conducted of 757 Navajos from the cohort of Colorado Plateau uranium miners. METHODS: Vital status was followed from 1960 to 1990. Standardized mortality ratios were estimated, with combined New Mexico and Arizona non-White mortality rates used for comparison. Cox regression models were used to evaluate exposure-response relationships. RESULTS: Elevated standardized mortality ratios were found for lung cancer (3.3), tuberculosis (2.6), and pneumoconioses and other respiratory diseases (2.6). Lowered ratios were found for heart disease (0.6), circulatory disease (0.4), and liver cirrhosis (0.5). The estimated relative risk for a 5-year duration of exposure vs none was 3.7 for lung cancer, 2.1 for pneumoconioses and other respiratory diseases, and 2.0 for tuberculosis. The relative risk for lung cancer was 6.9 for the midrange of cumulative exposure to radon progeny compared with the least exposed. CONCLUSIONS: Findings were consistent with those from previous studies. Twenty-three years after their last exposure to radon progeny, these light-smoking Navajo miners continue to face excess mortality risks from lung cancer and pneumoconioses and other respiratory diseases.

Adult↗
PubMed1994

Total serum testosterone and gonadotropins in workers exposed to dioxin.

Human reproductive endocrine data may be an important source of epidemiologic information in regard to the toxic potential of 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). The association of serum dioxin with total serum testosterone, luteinizing hormone, and follicle-stimulating hormone was examined in 248 chemical production workers from New Jersey and Missouri plants and 231 nonexposed neighborhood referents who participated in a medical evaluation in 1987. In linear regression analyses, current serum dioxin was positively and significantly related to luteinizing hormone and follicle-stimulating hormone and inversely related to total testosterone after adjustment for potential confounders (p < 0.05). These trends were also apparent in logistic regression analyses, in which the authors examined the odds ratios of high luteinizing hormone (> 28 IU/liter), high follicle-stimulating hormone (> 31 IU/liter), and low testosterone (< 10.4 nmol/liter) by serum dioxin quartiles. There was a greater prevalence of high luteinizing hormone among workers in the second (odds ratio (OR) = 1.9, 95% confidence interval (CI) 0.7-5.5), third (OR = 2.5, 95% CI 0.9-7.3), and fourth (OR = 1.9, 95% CI 0.7-5.0) quartiles of serum dioxin compared with referents. For follicle-stimulating hormone, the authors observed a greater prevalence of high follicle-stimulating hormone among workers in the fourth quartile (OR = 2.0, 95% CI 0.7-5.6) compared with referents. Similarly, the prevalence of low testosterone was two to four times greater among workers in the second (OR = 3.9, 95% CI 1.3-11.3), third (OR = 2.7, 95% CI 0.9-8.2), and fourth quartiles (OR = 2.1, 95% CI 0.8-5.8) than among referents. The trends observed in these data offer human evidence of alterations in male reproductive hormone levels associated with dioxin exposure. The results support the animal literature in which dioxin-related effects have been observed on the hypothalamic-pituitary-Leydig-cell axis and on testosterone synthesis.

Adult↗
PubMed1992

Fluorocarbon 113 exposure and cardiac dysrhythmias among aerospace workers.

We investigated the cardiotoxic effects of 1,1,2-Trichloro-1,2,2- Trifluoroethane (fluorocarbon 113 or FC113) exposures among healthy workers cleaning rocket and ground support equipment for the National Aeronautic and Space Administration (NASA) programs. Exposure and ambulatory electrocardiographic (ECG) monitoring data were evaluated on 16 workers, each of whom was examined on exposed and nonexposed workdays. We examined whether there was a greater rate of dysrhythmias on an exposed workday relative to a nonexposed workday. Overall, we found no within subject differences in the rate of ventricular and supraventricular premature beats (number per 1,000 heart beats), fluctuations in the length of the P-R interval, or heart rate. We found that levels of FC113 exposures below the Occupational Safety and Health Administration (OSHA) 8-hour time-weighted-average (TWA) standard of 1,000 ppm did not induce cardiac dysrhythmias or subtle changes in cardiac activity. However, because fluorocarbons may sensitize the heart to epinephrine, this study's negative findings based on sedentary and fairly healthy workers may not be generalizable to other populations of workers who are not as healthy or engaged in more physically demanding work.

Adult↗
PubMed1992

Effects of exposure to carbon disulphide on low density lipoprotein cholesterol concentration and diastolic blood pressure.

The relation of carbon disulphide (CS2) exposure to risk factors for ischaemic heart disease was recently examined using data from a 1979 cross sectional study of 410 male textile workers, of whom 165 were exposed and 245 were unexposed to CS2. Average eight hour CS2 exposure concentrations ranged from 0.6 to 11.8 ppm by job title category among the exposed workers. A significant and positive linear trend in low density lipoprotein cholesterol concentration (LDLc) and diastolic blood pressure with increasing CS2 exposure was found after adjustment for potential confounders. When exposure was examined as a categorical variable (none, low, moderate, and high), the high exposure group had an adjusted mean LDLc that was 0.32 mmol/l greater than the non-exposed group (p = 0.02), and an adjusted mean diastolic blood pressure that was 3.16 mm Hg greater than the non-exposed group (p = 0.09). The effect of CS2 on diastolic blood pressure was strengthened in analyses limited to exposed workers: the high exposure group had an adjusted mean diastolic blood pressure that was 5 mm Hg greater than that of the low exposed group (p = 0.03). Triglyceride, high density lipoprotein cholesterol, and fasting glucose concentration, and systolic blood pressure were not affected by exposure. Blood lead concentration was positively associated with systolic and diastolic blood pressure. The results indicate that relatively modest exposure to CS2 may raise LDLc concentration and diastolic blood pressure and suggest mechanisms by which exposure to CS2 may influence risk of ischaemic heart disease. Also the results provide further support for the hypothesis of a possible association between blood lead concentration and blood pressure.

Adult↗