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Biomedical subjects

S Wing

Publications and source records attributed to S Wing.

At least 19 recordsLinked to original sources
PubMed2000

A case control study of multiple myeloma at four nuclear facilities.

PURPOSE: Reported elevations of multiple myeloma among nuclear workers exposed to external penetrating ionizing radiation, based on small numbers of cases, prompted this multi-facility study of workers at US Department of Energy facilities. METHODS: Ninety-eight multiple myeloma deaths and 391 age-matched controls were selected from the combined roster of 115,143 workers hired before 1979 at Hanford, Los Alamos National Laboratory, Oak Ridge National Laboratory, and the Savannah River site. These workers were followed for vital status through 1990 (1986 for Hanford). Demographic, work history, and occupational exposure data were derived from personnel, occupational medicine, industrial hygiene, and health physics records. Exposure-disease associations were evaluated using conditional logistic regression. RESULTS: Cases were disproportionately African American, male, and hired prior to 1948. Lifetime cumulative whole body ionizing radiation dose was not associated with multiple myeloma, however, there was a significant effect of age at exposure, with positive associations between multiple myeloma and doses received at older ages. Dose response associations increased in magnitude with exposure age (from 40 to 50) and lag assumption (from 5 to 15 years), while a likelihood ratio goodness of fit test reached the highest value for cumulative doses received at ages above 45 with a 5-year lag (X2=5.43,1 df; relative risk = 6.9% per 10 mSv). Dose response associations persisted with adjustment for potential confounders. CONCLUSIONS: Multiple myeloma was associated with low level whole body penetrating ionizing radiation doses at older ages. The exposure age effect is at odds with interpretations of A-bomb survivor studies but in agreement with several studies of cancer among nuclear workers.

Age Factors↗
PubMed2000

Environmental injustice in North Carolina's hog industry.

Rapid growth and the concentration of hog production in North Carolina have raised concerns of a disproportionate impact of pollution and offensive odors on poor and nonwhite communities. We analyzed the location and characteristics of 2,514 intensive hog operations in relation to racial, economic, and water source characteristics of census block groups, neighborhoods with an average of approximately 500 households each. We used Poisson regression to evaluate the extent to which relationships between environmental justice variables and the number of hog operations persisted after consideration of population density. There are 18.9 times as many hog operations in the highest quintile of poverty as compared to the lowest; however, adjustment for population density reduces the excess to 7.2. Hog operations are approximately 5 times as common in the highest three quintiles of the percentage nonwhite population as compared to the lowest, adjusted for population density. The excess of hog operations is greatest in areas with both high poverty and high percentage nonwhites. Operations run by corporate integrators are more concentrated in poor and nonwhite areas than are operations run by independent growers. Most hog operations, which use waste pits that can contaminate groundwater, are located in areas with high dependence on well water for drinking. Disproportionate impacts of intensive hog production on people of color and on the poor may impede improvements in economic and environmental conditions that are needed to address public health in areas which have high disease rates and low access to medical care as compared to other areas of the state.

Black or African American↗
PubMed2000

Intensive livestock operations, health, and quality of life among eastern North Carolina residents.

People who live near industrial swine operations have reported decreased health and quality of life. To investigate these issues, we surveyed residents of three rural communities, one in the vicinity of an approximately 6,000-head hog operation, one in the vicinity of two intensive cattle operations, and a third rural agricultural area without livestock operations that use liquid waste management systems. Trained interviewers obtained information about health symptoms and reduced quality of life during the previous 6 months. We completed 155 interviews, with a refusal rate of 14%. Community differences in the mean number of episodes were compared with adjustment for age, sex, smoking, and employment status. The average number of episodes of many symptoms was similar in the three communities; however, certain respiratory and gastrointestinal problems and mucous membrane irritation were elevated among residents in the vicinity of the hog operation. Residents in the vicinity of the hog operation reported increased occurrences of headaches, runny nose, sore throat, excessive coughing, diarrhea, and burning eyes as compared to residents of the community with no intensive livestock operations. Quality of life, as indicated by the number of times residents could not open their windows or go outside even in nice weather, was similar in the control and the community in the vicinity of the cattle operation but greatly reduced among residents near the hog operation. Respiratory and mucous membrane effects were consistent with the results of studies of occupational exposures among swine confinement-house workers and previous findings for neighbors of intensive swine operations. Long-term physical and mental health impacts could not be investigated in this study.

Adult↗
PubMed2000

Concentrated swine feeding operations and public health: a review of occupational and community health effects.

Recent industry changes in swine-management practices have resulted in a growing controversy surrounding the environmental and public health effects of modern swine production. The numerous wastes produced by intensive swine production not only pose a significant challenge to effective environmental management but also are associated with decreased air quality in confinement houses, potentially transferable antimicrobial resistance patterns, and several infectious agents that can be pathogenic to humans. Published studies have documented a variety of contaminants, microbial agents, and health effects in those occupationally exposed to swine, and these have provided the groundwork for an increasing body of research to evaluate possible community health effects. Nonetheless, several factors limit our ability to define and quantify the potential role of intensive swine-rearing facilities in occupational and community health. Our incomplete understanding and ability to detect specific exposures; the complicated nature of disease etiology; pathogenesis; and surveillance; and the inherent difficulties associated with study design all contribute to the inadequate level of knowledge that currently prevails. However; an evaluation of the published literature; and a recognition of the elements that may be compromising these studies; provides the foundation from which future studies may develop.

Air Pollutants, Occupational↗
PubMed1999

Greater sensitivity to ionizing radiation at older age: follow-up of workers at Oak Ridge National Laboratory through 1990.

BACKGROUND: Workers at Oak Ridge National Laboratory (ORNL) were individually monitored for whole body exposure to ionizing radiation. Studies of these workers may provide valuable information about the long-term effects of occupational exposure to ionizing radiation. Since biological changes occur as adults age, a potentially important question in these investigations is whether sensitivity to the carcinogenic effects of ionizing radiation changes with age at exposure. METHODS: Vital status and cause of death were ascertained through 1990 for 8307 white males hired at ORNL from 1943 through 1972. Associations between whole body ionizing radiation dose and all-cancer mortality were quantified using life table regression methods for time dependent exposures. Analyses focused of differences in radiation-cancer associations with age at exposure. Length of follow-up, period of hire, and age at risk were considered as alternative explanations for effects of age at exposure. RESULTS: Cumulative radiation dose was associated with a 1.8% (SE = 0.9) increase in all-cancer mortality per 10 mSv, assuming a 10-year lag between exposure and mortality. However, radiation doses received at older ages exhibited larger associations with cancer mortality than doses received at younger ages. Doses received after age 45 were associated with a 5.9% (SE = 1.7) increase in cancer mortality per 10 mSv, adjusted for doses received before age 45. Dose-response associations between cancer mortality and doses received after age 45 appeared consistent across periods of follow-up, periods of hire, and ages at risk. CONCLUSIONS: Findings suggest that sensitivity to the carcinogenic effects of ionizing radiation may increase with older ages at exposure. More attention should be given to the role of age at exposure in studies of the health effects of low-level exposure to ionizing radiation, and to efforts to limit exposure to ionizing radiation.

Adult↗
PubMed1999

Radiation and mortality of workers at Oak Ridge National Laboratory: positive associations for doses received at older ages.

We examined associations between low-level exposure to ionizing radiation and mortality among 14,095 workers hired at the Oak Ridge National Laboratory between 1943 and 1972. Workers at the facility were individually monitored for external exposure to ionizing radiation and have been followed through 1990 to ascertain cause of death information. Positive associations were observed between low-level exposure to external ionizing radiation and mortality. These associations were larger for doses received after 45 years of age, larger under longer lag assumptions, and primarily due to cancer causes of death. All cancer mortality was estimated to increase 4.98% [standard error (SE) = 1.5] per 10-mSv cumulative dose received after age 45 under a 10-year lag, and 7.31% (SE = 2.2) per 10-mSv cumulative dose received after age 45 under a 20-year lag. Associations between radiation dose and lung cancer were of similar magnitude to associations between radiation dose and all cancers except lung cancer. Nonmalignant respiratory disease exhibited a positive association with cumulative radiation dose received after age 45, whereas ischemic heart disease exhibited no association with radiation dose. These findings suggest increases in cancer mortality associated with low-level external exposure to ionizing radiation and potentially greater sensitivity to the carcinogenic effects of ionizing radiation with older ages at exposure.

Adult↗
PubMed1998

Proparathyroid hormone-related protein is associated with the chaperone protein BiP and undergoes proteasome-mediated degradation.

Parathyroid hormone-related peptide (PTHrP) is an important causal factor for hypercalcemia associated with malignancy. In addition to the endocrine functions attributed to secretory forms of the peptide, PTHrP also plays a local role as a mediator of cellular growth and differentiation presumably at least in part through intracellular pathways. In studying the post-translational regulation of PTHrP, we observed that PTHrP was conjugated to multiple ubiquitin moieties. We report here that the proteasome is responsible for the degradation of the endoplasmic reticulum-associated precursor, pro-PTHrP. Cells expressing prepro-PTHrP and exposed to lactacystin accumulate pro-PTHrP assessed by anti-pro specific antibodies. Brefeldin A-treated cells also accumulate pro-PTHrP suggesting that degradation does not occur in the endoplasmic reticulum (ER) lumen. Subcellular fractionation of both lactacystin and brefeldin A-treated cells indicated that accumulated pro-PTHrP resides in microsomal fractions with a portion of the protein exposed to the cytosolic side of the ER membrane as assessed by protease protection experiments. Immunoprecipitation and Western blot analysis identified pro-PTHrP in association with the ER molecular chaperone protein BiP. We conclude that pro-PTHrP from the ER can gain access to the cytoplasmic side of the ER membrane where it can undergo ubiquitination and degradation by the proteasome.

Acetylcysteine↗
PubMed1998

Methods for investigating age differences in the effects of prolonged exposures.

People experience physiological changes with age which may lead to changes in sensitivity to many kinds of exposure. In situations of prolonged, low level exposure, differences in the effects of exposures received at different ages may be difficult to evaluate, since study members receive low level exposures over a range of ages. Such investigations require examination of the effects of different age-patterns of exposure. Three approaches to investigating age-related variability in the effects of prolonged exposures are described: subcohort analyses; the use of smooth weighting functions; and the evaluation of separate effects of cumulative exposures received at different age ranges. Each method can contribute to the overall evaluation of age-specific exposure effects. These methods are illustrated with occupational cohort data for employees of Oak Ridge National Laboratory. The methods presented in this paper should facilitate examination of the effects of aging on sensitivity to prolonged exposures.

Adult↗
PubMed1998

Community occupational structure, medical and economic resources, and coronary mortality among U.S. blacks and whites, 1980-1988.

PURPOSE: To examine the association between coronary heart disease (CHD) mortality, economic and medical resources, and county occupational structure. METHODS: U.S. counties were classified into five occupational structure categories based on the percentage of workers in white-collar occupations. Directly age-adjusted CHD mortality rates (from vital statistics and Census data) and economic and medical care data (from Census and Area Resource File data) were calculated for each occupational structure category. Participants were black and white, men and women, aged 35-64 years, in the U.S. during 1980-88. CHD mortality rates and economic and medical care data were compared across occupational structure categories. RESULTS: Among blacks, CDH rates were highest in counties with intermediate levels of occupational structure; rates among whites were inversely associated with occupational structure. Per capita levels of income and numbers of medical-care providers were positively associated with occupational structure. CONCLUSION: Strategies to improve the resources of disadvantaged communities and the access of black workers to local occupational opportunities may be important for CHD prevention in high risk populations.

Adult↗
PubMed1998

Whose epidemiology, whose health?

Simplistic claims about the objectivity of science have been challenged from a variety of perspectives. Evaluation of the external context of production of knowledge and the methodological approaches to posing questions and assembling evidence shows that there is no pure "science"; rather, all scientific knowledge is shaped by the social history of its production. Examples are given of how quantitative concepts in modern epidemiology influence the recognition of the causes of disease. The author uses the phenomenon of intensive swine production by vertically integrated agribusiness to illustrate how broad problems such as environmental racism, agricultural determinants of nutrition, loss of natural resources, and conditions conducive to emergence of new diseases are hidden by epidemiological approaches that fit into corporate policy perspectives. It is critically important to ask who produces epidemiological knowledge, and whose health is promoted by that knowledge.

Bias↗
PubMed1997

Preproparathyroid hormone-related protein, a secreted peptide, is a substrate for the ubiquitin proteolytic system.

Parathyroid hormone-related protein (PTHrP) is an important causal factor of hypercalcemia associated with malignancy. PTHrP also modulates cell growth and differentiation of normal cells through mechanisms that include binding to cell surface-specific receptors as well as by possible intracellular routes. To understand the regulation of intracellular PTHrP expression, post-translational processing of PTHrP was investigated. Using cell-free translations it was shown that PTHrP can be ligated efficiently to multiple ubiquitin moieties. Both conjugation to ubiquitin and degradation of prepro-PTHrP synthesized in vitro were ATP-dependent. Translation in vitro in the presence of the proteasome inhibitor MG-132 abolished the degradation of PTHrP. Treatment of cells, cotransfected with hemagglutinin-tagged ubiquitin and histidine-tagged prepro-PTHrP, with MG-132, led to the accumulation of ubiquitinated prepro-PTHrP. Deletion mutagenesis experiments indicated that both the prepro secretory domain and a PEST (amino acid residues Pro (P), Glu (E), and/or Asp (D), Ser (S), and Thr (T)) motif in the COOH-terminal region of the protein were not required as cis-acting determinants for ubiquitination. This is the first report of a wild-type secretory polypeptide serving as a substrate of the ubiquitin proteolytic pathway. These results suggest that the ubiquitin-dependent proteolytic pathway is involved in regulating the metabolic stability of intracellular PTHrP, and this regulation may be an important mechanism for modulating its effects on cell growth and differentiation.

Adenosine Triphosphate↗
PubMed1997

A simple program to create exact person-time data in cohort analyses.

BACKGROUND: Before disease rates can be calculated a tabulation of the length of follow-up for each person in the cohort has to be made. In complicated analyses such tabulations are often stratified by many characteristics, some which show no change with time, such as gender or year of birth, and some which do change with time, such as age or cumulative exposure. Available computer programs often restrict the way these tables can be made, particularly when handling time-dependent variables. METHODS: This paper presents a simple computer program which calculates the length of follow-up for each person in a study. RESULTS: Person-time data can be tabulated by a large number of variables using this method. This program is extremely flexible in the way that time-dependent variables can be created, can categorize observations by any unit of person-time, and will run on a range of platforms including a personal computer. CONCLUSIONS: This method should simplify the task of creating person-time data for analyses of disease rates in epidemiological studies.

Cohort Studies↗
PubMed1997

A reevaluation of cancer incidence near the Three Mile Island nuclear plant: the collision of evidence and assumptions.

Previous studies concluded that there was no evidence that the 1979 nuclear accident at Three Mile Island (TMI) affected cancer incidence in the surrounding area; however, there were logical and methodological problems in earlier reports that led us to reconsider data previously collected. A 10-mile area around TMI was divided into 69 study tracts, which were assigned radiation dose estimates based on radiation reading and models of atmospheric dispersion. Incident cancers from 1975 to 1985 were ascertained from hospital records and assigned to study tracts. Associations between accident doses and incidence rates of leukemia, lung cancer, and all cancer were assessed using relative dose estimates calculated by the earlier investigators. Adjustments were made for age, sex, socioeconomic characteristics, and preaccident variation in incidence. Considering a 2-year latency, the estimated percent increase per dose unit +/- standard error was 0.020 +/- 0.012 for all cancer, 0.082 +/- 0.032 for lung cancer, and 0.116 +/- 0.067 for leukemia. Adjustment for socioeconomic variables increased the estimates to 0.034 +/- 0.013, 0.103 +/- 0.035, and 0.139 +/- 0.073 for all cancer, lung cancer, and leukemia, respectively. Associations were generally larger considering a 5-year latency, but were based on smaller numbers of cases. Results support the hypothesis that radiation doses are related to increased cancer incidence around TMI. The analysis avoids medical detection bias, but suffers from inaccurate dose classification; therefore, results may underestimate the magnitude of the association between radiation and cancer incidence. These associations would not be expected, based on previous estimates of near-background levels of radiation exposure following the accident.

Dose-Response Relationship, Radiation↗
PubMed1997

A mortality study of employees of the nuclear industry in Oak Ridge, Tennessee.

An analysis was conducted of 27,982 deaths among 106,020 persons employed at four Federal nuclear plants in Oak Ridge, Tennessee, between 1943 and 1985. The main objectives were to extend the evaluation of the health effects of employment in the nuclear industry in Oak Ridge to include most workers who were omitted from earlier studies, to compare the mortality experience of workers among the facilities, to address methodological problems that occur when individuals employed at more than one facility are included in the analysis, and to conduct dose-response analyses for those individuals with potential exposure to external radiation. All-cause mortality and all-cancer mortality were in close agreement with national rates. The only notable excesses occurred for white males for lung cancer [standardized mortality ratio (SMR) = 1.18, 1,849 deaths] and non-malignant respiratory disease (SMR = 1.12, 1,568 deaths). A more detailed analysis revealed substantial differences in death rates among workers at the Oak Ridge plants. Evaluation of internally adjusted log SMRs using Poisson regression showed that workers employed only at Tennessee Eastman Corporation or K-25 and at multiple facilities had higher death rates than similar workers employed only at X-10 or Y-12, and that the differences were primarily due to non-cancer causes. Analysis of selected cancer causes for white males indicated large differences among the workers at the different facilities for lung cancer, leukemia and other lymphatic cancer. Dose-response analyses for external penetrating radiation were limited to a subcohort of 28,347 white males employed at X-10 or Y-12. Their collective recorded dose equivalent was 376 Sv. There was a strong "healthy worker effect" in this subcohort-all-cause SMR = 0.80 (4,786 deaths) and all-cancer SMR = 0.87 (1,134 deaths). Variables included in the analyses were age, birth cohort, a measure of socioeconomic status, length of employment, internal radiation exposure potential and facility. For external radiation dose with a 10-year lag, the excess relative risk was 0.31 per Sv (95% CI = -0.16, 1.01) for all causes and 1.45 per Sv (95% CI = 0.15, 3.48) for all cancer. The estimated excess relative risk for leukemia was negative but imprecisely determined. A preliminary dose adjustment procedure was developed to compensate for missing dose but not other dosimetry errors. Results of the analyses using the adjusted doses suggest that the effect of missing dose is an upward bias in dose-response coefficients and test statistics.

Dose-Response Relationship, Radiation↗
PubMed1996

Race differences in estimates of sudden coronary heart disease mortality, 1980-1988: the impact of ill-defined death.

Coronary heart disease (CHD) deaths occurring outside of hospitals or in emergency rooms (OH/ER) have been used to estimate sudden CHD mortality. This study quantifies the potential impact of natural deaths coded to an unspecified cause on race differences in sudden CHD estimates, during 1980-1988. Death certificate data for OH/ER deaths in 40 U.S. states were used to create annual age-adjusted rates for sudden CHD and sudden CHD rates revised to include deaths with an unspecified cause (ICD9, 780-799). Revising the mortality rates to include unspecified deaths results in greater racial disparities for estimates of sudden CHD. In 1980, black-white race differences went from 89 to 128 and 103 to 121 (per 100,000) for men and women, respectively, with revision. Among blacks, revised sudden CHD mortality declined approximately 22%, during 1980-1988, compared to 10% for unrevised sudden CHD; with no observed effect of revision on percent declines among whites. Previous studies may have underestimated declines in racial disparities of sudden CHD, due to improved quality of OH/ER death certification among blacks. Improved access to routine and emergency medical care, through increased affordability and greater availability, may be important to address higher OH/ER CHD among blacks.

Adult↗
PubMed1996

Urbanisation and coronary heart disease mortality among African Americans in the US South.

STUDY OBJECTIVE: Despite significant declines since the late 1960s, coronary mortality remains the leading cause of death for African Americans. African Americans in the US South suffer higher rates of cardiovascular disease than African Americans in other regions; yet the mortality experiences of rural-dwelling African Americans, most of whom live in the South, have not been described in detail. This study examined urban-rural differentials in coronary mortality trends among African Americans for the period 1968-86. SETTING: The United States South, comprising 16 states and the District of Columbia. STUDY POPULATION: African American men and women aged 35-74 years. DESIGN: Analysis of urban-rural differentials in temporal trends in coronary mortality for a 19 year study period. All counties in the US South were grouped into five categories: greater metropolitan, lesser metropolitan, adjacent to metropolitan, semirural, and isolated rural. Annual age adjusted mortality rates were calculated for each urban status group. In 1968, observed excesses in coronary mortality were 29% for men and 45% for women, compared with isolated rural areas. Metropolitan areas experienced greater declines in mortality than rural areas, so by 1986 the urban-rural differentials in coronary mortality were 3% for men and 11% for women. CONCLUSIONS: Harsh living conditions in rural areas of the South precluded important coronary risk factors and contributed to lower mortality rates compared with urban areas during the 1960s. The dramatic transformation from an agriculturally based economy to manufacturing and services employment over the course of the study period contributed to improved living conditions which promoted coronary mortality declines in all areas of the South; however, the most favourable economic and mortality trends occurred in metropolitan areas.

Adult↗
PubMed1995

The shifting stroke belt. Changes in the geographic pattern of stroke mortality in the United States, 1962 to 1988.

BACKGROUND AND PURPOSE: The factors that contribute to the Stroke Belt--a concentration of high stroke mortality rates in the southeastern United States--remain unidentified. Previous hypotheses that focused on physical properties of the area have not been confirmed. This study describes changes in the locations of areas with the highest rates of stroke mortality and the implications for new hypotheses regarding the Stroke Belt. METHODS: We calculated annual, age-adjusted stroke mortality rates for black women, black men, white women, and white men for the years 1962 to 1988 using a three-piece log-linear regression model. Maps were produced with the state economic area (SEA) as the unit of analysis. The baseline Stroke Belt was defined as the area with the largest concentration of high-quintile SEAs in 1962. RESULTS: The concentration of high-rate SEAs tended to shift away from the Piedmont region of the Southeast and toward the Mississippi River valley. For example, whereas among black women in 1962, 72% of SEAs in the baseline Stroke Belt were in the highest quintile, by 1988 this percentage had dropped to 48%. Similar patterns were observed for the other race/sex groups. CONCLUSIONS: Temporal changes in the location of areas with the highest stroke mortality rates suggest that new hypotheses for understanding the geographic pattern of stroke mortality should consider temporal trends in a variety of medical, socioeconomic, and behavioral factors.

Adult↗