Biomedical subjects

C M Shy

Publications and source records attributed to C M Shy.

At least 37 records · Page 2Linked to original sources

PubMed1990

Micronuclei in epithelial cells from sputum of uranium workers.

The cytogenetic effects of exposure to radon progeny and cigarette smoke were assessed with the exfoliated-cell micronucleus assay among 99 uranium workers. Cells with micronuclei were determined in one sputum specimen from each worker. Exposure to radon progeny and smoking habits were classified from interview data collected at the same time as the sputum specimens. Underground miners were considered exposed to radon progeny, and the other workers were considered unexposed. Neither radon progeny exposure nor cigarette smoking had any appreciable effect on the prevalence of cells with micronuclei; the crude prevalence ratios for the two groups were 1.0 (95% confidence interval 0.7-1.4) and 0.9 (95% confidence interval 0.6-1.3), respectively. The effects of radon and smoking were not confounded by each other or by age, nor were they synergistic. These findings cast doubt on the use of sputum-based micronucleus assay in epidemiologic studies of other populations exposed to occupational or environmental lung carcinogens.

DNA Damage↗

PubMed1990

Lead in petrol: the mistake of the XXth century.

The health aspects of the use of lead in petrol were evaluated in the 1920s in the United States of America and, in spite of warnings from certain lead-toxicity experts, lead addition to petrol became standard international practice. Available data now show that lead in petrol at the scale of use in the 1970s produced significant environmental lead contamination and increased average blood-lead levels in the general population. National sample surveys of blood-lead levels in the United States carried out annually from 1976 show a decreasing trend closely correlated with the use of lead in petrol. Recent longitudinal epidemiological studies have concluded that the exposure levels associated with lead in petrol can cause a reduced average mental ability in children. These studies accounted for the potential confounding from socioeconomic and other factors. The practical conclusion from the studies reviewed is that there should be as little human lead exposure as possible, because there may be no threshold for the effects occurring and many thousand children have already been affected in the United States and other countries. The environmental health calamity caused by lead in petrol could have been avoided if the initial warnings had been heeded and better preliminary research of the health issues had been carried out. Nevertheless, incontrovertible proof of causality should not be required before regulations are made to protect public health.

Air Pollutants↗

PubMed1989

Injuries on the fireground: risk factors for traumatic injuries among professional fire fighters.

This case-control study within a metropolitan fire department evaluated the effect of self-contained breathing apparatus (SCBA) and other risk factors on three types of injury at the scene of a fire (smoke inhalation, burns, and falls). Data on 75 injured fire fighters and 144 controls came from telephone interviews and department records. The two sets of uninjured fire-fighter controls were matched to cases on incident (n = 72) or on job position and fire type and size (n = 72). Smoke inhalation cases were not significantly different from controls in SCBA use, cigarette smoking, previous fires in the shift, or injury history. Jobs with high risk of burns included nozzle operator, engine officer, and forcible-entry person in first-due companies (OR = 20.1). Other risk factors for burns were: basement origin of fire (OR = 10.2); prior fire-fighting training outside the present department (same fire: OR = 11.2; similar fire: OR = 3.9); and on-duty injury in the prior 12 months (same fire: OR = 4.3; similar fire: OR = 3.5). When other risk factors were considered, consistent SCBA use was associated with falls (same fire: OR = 11.8; similar fire: OR = 4.3) but not with burns. Risk of falls also was elevated among members of truck companies (OR = 17.7) and fire fighters without children (same fire: OR = 8.4; similar fire: OR = 7.4). On-duty injury in the past 12 months was associated with falls when one compared cases with similar-fire controls (OR = 5.5), but not with controls attending the same fire. Neither age nor experience was related to injury in this population.

Accidental Falls↗

PubMed1989

Review, discussion, and summary of epidemiological studies.

This paper reviews and summarizes the epidemiological studies presented at the Symposium on the Health Effects of Acid Aerosols. Two studies of acute episodes examined different indicators of respiratory morbidity before, during, and after the January 1985 air pollution event in western Europe. In the U.K. no increase in respiratory morbidity, as reported by a group of general practitioners, was observed, but measured concentrations of air pollutants failed to substantiate the existence of an identifiable episode. In the Federal Republic of Germany, the air pollution episode was documented and was associated with a 10 to 25% increase in several indicators of respiratory and cardiovascular morbidity, but could not be attributed to acidic aerosols as such. In two further studies, investigators related day-to-day variations in air pollution with admissions to acute care hospitals in southern Ontario for respiratory disease over a 9-year period, and with daily mortality in London from 1963 to 1972. In the study of hospital admissions, significant correlations were observed with sulfate, ozone, and SO2 pollution, but the data were insufficient to isolate the separate or combined effects of these pollutants. In the London mortality analysis, the strongest correlations were observed for sulfuric acid levels of the prior day, but prefiltering of the mortality data may have dampened the true relationship, and age- and cause-specific analyses would have been desirable. Finally two reports on chronic effects of residence in high air pollution areas have thus far made little contribution to the evidence for an adverse effect of specific pollutants.

Acid Rain↗

PubMed1988

An epidemiologic study of respiratory health effects in a group of North Carolina furniture workers.

Woodworking is known to be associated with nasal cancer and with western red cedar asthma, but research is inconsistent with regard to respiratory health effects among furniture workers. The authors tested the hypotheses that employment in a North Carolina hardwood furniture plant was related to the prevalence of respiratory symptoms and to impairment of pulmonary function. Chronic symptom prevalence generally showed no significant differences between wood dust jobs and control exposures; however, frequent sneezing and eye irritation were significantly (P less than .05) correlated with wood dust exposed jobs; in both cases the prevalence odds ratio was 4.0. Peak flow was the only pulmonary function measure that correlated significantly (P = .0345) with wood dust employment. The difference in forced vital capacity suggested a weak association with current employment in finishing jobs, whereas the difference in peak flow showed a modest correlation with the fraction of particulate less than 10 microns. The relevance of the present associations to regulatory changes and research needs is discussed.

Adult↗

PubMed1988

Sunlight and other risk factors for cataracts: an epidemiologic study.

A case control study was conducted in North Carolina to explore the relation between individual exposure to sunlight and the risk of cataracts. One hundred thirteen cases and 161 controls aged 40-69 at diagnosis were studied. Sunlight exposure was inferred from interview data on residency and time spent in the sun, combined with solar radiation data from the National Climatic Data Center. Sunlight exposure was very slightly related to all types of opacities combined. Although the numbers of cases with each type of opacity was small, the risk of cataracts was slightly increased in medium and high exposure categories for persons having cortical or posterior subcapsular opacities only, but not nuclear sclerotic changes. Persons with dark brown or hazel eyes are at increased risk. An unexpected finding was that persons who reported using tranquilizers for six months were at increased risk.

Aged↗

PubMed1988

Respiratory health effects from occupational exposure to wood dusts.

Occupational exposure to wood dusts has been well established as a cause of nasal cancer, dermatitis, and pneumonites from molds growing in wood chips. With the exception of studies on western red cedar asthma, there is a dearth of information on the respiratory toxicity of wood dust exposure. This paper reviews the clinical and epidemiologic literature and identifies the specific woods (with botanical names) and their respiratory disease correlates, including pulmonary function declines, chronic and acute symptoms, and impaired mucociliary transport.

Dust↗

PubMed1985

Radiation, work experience, and cause specific mortality among workers at an energy research laboratory.

A retrospective cohort mortality study was conducted among 8375 white male employees who had worked at the Oak Ridge National Laboratory for at least one month between 1943 and 1972. This plant has been the site of energy related research, including uranium and plutonium reactor technology and radioisotope production. Radiation doses, primarily from gamma rays, were generally low; the median cumulative exposure for workers was 0.16 rems. Historical follow up was conducted for the years 1943-77 and ascertainment of vital status was achieved for 92.3% of the cohort. Standardised mortality ratios (SMRs) were computed to contrast the subjects' cause specific mortality experience with that of the United States white male population. The observed number of 966 deaths from all causes was 73% of the number expected. Mortality deficits were also seen for arteriosclerotic heart disease (SMR = 0.75; 344 observed) and all cancers (SMR = 0.78; 194 observed). These results are indicative of the healthy worker effect and the favourable influence on health of the cohort's relatively high socioeconomic status. Non-statistically significant raised SMRs were seen for all leukaemias (SMR = 1.49, 16 observed), cancer of the prostate (SMR = 1.16, 14 observed), and Hodgkin's disease (SMR = 1.10, 5 observed). Internal comparisons of mortality (standardised rate ratios, SRRs) were made between subgroups of the cohort according to radiation dose level and duration of employment in various job categories. No consistent gradients of cause specific mortality were detected for radiation exposure. Leukaemia mortality was highest among workers with greater than or equal to 10 years employment in engineering (SRR = 2.40) and maintenance (SRR = 3.12) jobs. The association of leukaemia with employment in engineering was unexpected; maintenance jobs entail potential exposures to radiation and to a wide range of organic chemicals; metals, and other substances.

Adolescent↗

PubMed1985

Chemical contamination of water supplies.

Man-made organic chemicals have been found in drinking water for many years. Their numbers and varieties increase as our analytical capabilities improve. The identified chemicals comprise 10 to 20% of the total organic matter present. These are volatile or low molecular weight compounds which are easily identified. Many of them are carcinogenic or mutagenic. Chlorinated compounds have been found in untreated well water at levels up to 21,300 micrograms/L and are generally present at higher levels in chlorine-treated water than in untreated water. Aggregate risk studies for cancer are summarized. The most common sites are: bladder, stomach, colon, and rectum. Such studies cannot be linked to individual cases. However, they are useful for identifying exposed populations for epidemiologic studies. Five case-control studies were reviewed, and significant associations with water quality were found for: bladder cancer in two studies, colon cancer in three and rectal cancer in four. A large study by the National Cancer Institute found that there had been a change in the source of raw water for 50% of the persons in one area between the years 1955 and 1975. Such flaws in the data may preclude finding a causal relation between cancer and contaminants in drinking water. Large case-control and cohort studies are needed because of the low frequency of the marker diseases, bladder and rectal cancer. Cohort studies may be precluded by variations in the kinds of water contaminants. Definitive questions about these issues are posed for cooperative effort and resolution by water chemists, engineers, and epidemiologists.

Carcinogens↗

PubMed1985

Mortality among workers in the Florida phosphate industry. I. Industry-wide cause-specific mortality patterns.

A retrospective cohort mortality study was conducted on 17,601 white and 4,722 nonwhite male workers in the Florida phosphate mining and chemical processing industry. Concerns about potential risks from naturally-occurring sources of ionizing radiation and anecdotal reports of lung cancer among workers prompted this investigation. Historical follow-up was conducted for the years 1949 to 1978. In comparison with U.S. rates, small excess of mortality rates of lung cancer were observed for white (standardized mortality ratio [SMR] equals 1.22) and nonwhite workers (SMR = 1.24); however, these excesses disappeared when contrasts were made with prevailing rates in Florida. Emphysema mortality was also slightly elevated in comparison with U.S. rates; the SMRs were 1.48 and 1.73 for white and nonwhite workers, respectively. Neither disease was related to overall length of employment. Detailed analyses of mortality in relation to work assignments are presented in the companion article.

Adult↗

PubMed1985

Mortality among workers in the Florida phosphate industry. II. Cause-specific mortality relationships with work areas and exposures.

Small excesses of lung cancer and emphysema mortality had been detected among an historical cohort of 17,601 white and 4,722 nonwhite Florida phosphate industry workers. Internal mortality rate comparisons were made between worker subcohorts classified according to length of employment in 16 work areas and according to employment duration in jobs grouped by potential exposures to 10 agents, including alpha radiation. The only consistent associations seen were increased lung cancer mortality rates among long-term workers in plant-wide services and skilled crafts jobs. There was no evidence to support causal associations with exposures characteristic of the phosphate industry.

Adult↗

PubMed1984

Smoking, alcohol, analgesics, and chronic duodenal ulcer. A controlled study of habits before first symptoms and before diagnosis.

The aim of the study was to investigate the role of smoking and alcohol and analgesic ingestion in the aetiology of chronic duodenal ulcer (DU). Exposure to these variables was studied during the lifetime and 1 year before the first ulcer symptom and 1 month before a diagnosis. The ulcer group of 100 patients was compared with 100 community controls matched for age, sex, and social grade. In men there was an increased risk of DU associated with smoking and alcohol ingestion both during the lifetime and 1 year before the first symptom. In women, there was an increased risk associated with smoking during the lifetime before the first symptom and with alcohol ingestion during the year before the first symptom. Analgesic ingestion was not a risk factor. In the month before diagnosis only smoking was commoner in the DU group. The data indicate that smoking and alcohol ingestion are risk factors for DU.

Age Factors↗

PubMed1984

A retrospective cohort mortality study among workers occupationally exposed to metallic nickel powder at the Oak Ridge Gaseous Diffusion Plant.

The Oak Ridge Gaseous Diffusion Plant (ORGDP) employed over 800 white male workers between 1 January 1948, and 31 December 1953, in the manufacture of "barrier" material that required metallic nickel powder in its production. A retrospective cohort study was conducted to determine whether persons working with metallic nickel powder have a higher mortality from cancers of the respiratory tract than non-nickel workers. A comparison group was defined as all white males employed at ORGDP sometime between 1 January 1948, and 31 December 1953, who had no indications of occupational involvement in barrier production. This group comprised over 7 500 workers. Vital status determination has been completed up to 31 December 1977, allowing at least 24 years of follow-up for all persons in the study. Death certificates were available for 97% of the deaths among the nickel workers and non-nickel worker groups. End-points of interest were selected site-specific cancers and the general overall pattern of disease-specific mortality. Mortality rates in the nickel workers and non-nickel worker groups were compared with those for the white male population of the United States and with each other. There was no evidence of increased mortality due to lung cancers or nasal sinus cancers in nickel workers. Increases (not statistically significant) in mortality due to cancers of the buccal cavity and pharynx, and of the digestive system were observed in the nickel worker group, compared with the non-nickel worker group.

Adolescent↗

PubMed1984

Plasma selenium and skin neoplasms: a case-control study.

Although experimental studies in animals show that selenium may prevent cancer, case-control studies of internal human cancers have been difficult to interpret because neoplastic tissue sequesters selenium. We therefore conducted a case-control study to examine the association between plasma selenium level and skin cancer, a neoplasm with minimal tumor mass at the time of diagnosis. The mean selenium level among patients with either basal cell epithelioma (N = 142), squamous cell carcinoma (N = 48), or both (N = 50), was 0.141 micrograms/g. This was significantly lower than the mean plasma selenium level of the 103 control subjects, which was 0.155 micrograms/g. The noncancer control groups were drawn from current clinic patients and past clinic patients. The logistic estimate of the odds ratio for the lowest versus the highest decile of selenium for all cases combined versus the group of current patient controls was 4.39; for all cases combined versus the past patient controls, the logistic estimate of the odds ratio was 5.81.

Adult↗

PubMed1983

Exposures and mortality among chrysotile asbestos workers. Part I: exposure estimates.

A detailed study of plant processes and dust control methods over the period 1930-1975 was conducted in an asbestos textile plant processing chrysotile. Linear statistical models for reconstructing historic dust exposure levels, taking into account textile processes, dust control measures, and job assignments, were developed. Parameters of these statistical models were estimated using 5,952 industrial hygiene sampling measurements covering the period 1930-1975. For most textile operations, exposure levels were significantly reduced by about 1940, when most engineering dust control measures were in place. Results of the exposure estimates indicated "precontrol" exposure levels to range from 3 to 78 fibers/cc with typical levels well above 10 fibers/cc. After textile operations were provided with dust control measures, estimated exposure levels ranged from 3 to 17 fibers/cc and were usually in the range of 5 to 10 fibers/cc. These exposure estimates were combined with an assessment of mortality among workers at this plant to investigate exposure-response relationships. Exposure-response results are presented in the companion manuscript in this volume.

Asbestos↗

PubMed1983

Exposures and mortality among chrysotile asbestos workers. Part II: mortality.

A retrospective cohort mortality study was conducted among a cohort of 1,261 white males employed one or more months in chrysotile asbestos textile operations and followed between 1940 and 1975. Statistically significant excess mortality was observed for all causes combined (standardized mortality ratio [SMR] = 150), lung cancer (SMR = 135), diseases of the circulatory system (SMR = 125), nonmalignant respiratory diseases (SMR = 294), and accidents (SMR = 134). Using estimated fiber exposure levels in conjunction with detailed worker job histories, exposure-response relationships were investigated. Strong exposure-response relationships for lung cancer and asbestos related non-malignant respiratory diseases were observed. Compared with data for chrysotile miners and millers, chrysotile textile workers were found to experience significantly greater lung cancer mortality at lower lifetime cumulative exposure levels. Factors such as differences in airborne fiber characteristics may partially account for the large differences in exposure response between textile workers and miners and millers.

Asbestos↗

PubMed1982

Occupation and oral cancer among women in the South.

A case-control interview study among 232 North Carolina women with oral or pharyngeal cancer and 410 matched controls evaluated the contribution of occupation to the high risk of this cancer among females in the South. Review of detailed occupational histories found no overall elevated odds ratios for employment in the textile, apparel, or hosiery industry, the major employer of women in the area. Risks also did not increase with years worked in the industry. The findings thus fail to confirm an association reported in surveys in the United States and Great Britain. A new clue to occupational factors was suggested by the excess risk associated with the electronics industry in coastal North Carolina, independent of the participants' tobacco habits.

Dust↗

PubMed1982

A study of acute respiratory disease in families exposed to different levels of Air pollution in the Great Salt Lake basin, Utah, 1971-1972 and 1972-1973.

The reported incidence of acute respiratory illness in families exposed to different concentrations of air pollution was studied during two consecutive school years. The purpose of the study was to determine the effect of increased exposure to sulfur dioxide and suspended particulate matter. In each of four study communities, the mothers of approximately 250 white families were contacted biweekly to obtain information regarding the occurrence of respiratory symptoms in each family member. Annual mean ambient sulfur dioxide concentrations in one community for the three years included in the study (1971-1973) were well above the current air quality standard of 80 micrograms/m3, while in the other three communities the annual sulfur dioxide concentrations were much lower (usually less than 40 micrograms/m3). Suspended particulate matter concentrations in high sulfur dioxide community were close to the limit designated by the annual standard (75 micrograms/m3) but actual exposures in the four communities probably were not excessive. Regression analyses of the data collected showed inconsistent associations between illness rates and educational attainment of the head of household, crowding in the home, bronchitis in parents or smoking of parents. However, once the effects of these factors were removed the adjusted rates showed little association with community of residence. It was concluded that the higher concentrations of sulfur dioxide in the Utah atmosphere could not be the cause of increases in acute respiratory illness in the exposed populations.

Adult↗