Biomedical subjects

S R Browning

Publications and source records attributed to S R Browning.

16 recordsLinked to original sources

PubMed2005

Sleepiness/fatigue and distraction/inattention as factors for fatal versus nonfatal commercial motor vehicle driver injuries.

A retrospective population-based case-control study was conducted to determine whether driver sleepiness/fatigue and inattention/distraction increase the likelihood that a commercial motor vehicle collision (CVC) will be fatal. Cases were identified as CVC drivers who died (fatal) and controls were drivers who survived (nonfatal) an injury collision using the Kentucky Collision Report Analysis for Safer Highways (CRASH) electronic database from 1998-2002. Cases and controls were matched on unit type and roadway type. Conditional logistic regression was performed. Driver sleepiness/fatigue, distraction/inattention, age of 51 years of age and older, and nonuse of safety belts increase the odds that a CVC will be fatal. Primary safety belt law enactment and enforcement for all states, commercial vehicle driver education addressing fatigue and distraction and other approaches including decreased hours-of-service, rest breaks and policy changes, etc. may decrease the probability that a CVC will be fatal.

Accidents, Occupational↗

PubMed2002

Regional assessment of atrazine exposure and incidence of breast and ovarian cancers in Kentucky.

The association between breast and ovarian cancers with endogenous estrogen or hormonally related events has led to the hypothesis that exposures to exogenous estrogenic compounds in the environment may increase the risk of these cancers. Atrazine, the most commonly used herbicide in the United States, belongs to this group of compounds and is widely used in corn production. This study is an expansion of a previous investigation conducted in Kentucky. Using secondary data, we derived several indices of environmental exposure to atrazine and examined the association between these measures and the incidence of breast and ovarian cancer in Kentucky over a 5-year period (1993-97). Exposure indices to atrazine were derived based on public water measurements, acres of corn planted, and pounds of atrazine sold. Data on breast and ovarian cancer incidence were obtained from the Kentucky Cancer Registry by county and by the 15 Area Development Districts (ADDs) in which the 120 counties are grouped. Poisson regression analyses adjusted for education and race were conducted separately for each index of exposure and for a combined total exposure score. All exposure measures were divided in quartiles for analysis. A null association was found for breast cancer across all exposure indices, both by county and by ADD. For ovarian cancer, the data suggest an inverse association, with increasing exposure linked to decreasing incidence rates, both at the county and ADD level. The following are the rate ratios (RR) and corresponding 95% confidence intervals, for the summary exposure scores in the three upper quartiles, using the lowest quartile as baseline (RR = 1.0), and the county as the unit of analysis: 1.01 (0.83-1.21), 0.77 (0.66-0.90), and 0.76 (0.65-0.88). Due to the ecologic nature of this study and inherent limitations, it is possible that other factors may be contributing to these findings. Studies using individual-level data are recommended to elucidate the relationships between estrogenic environmental exposures and female reproductive cancers.

Adult↗

PubMed2001

Solvent exposures in screen printing shops.

A comprehensive description of working conditions, exposure patterns for organic solvents, and related health symptoms among workers in ten small screen printing companies located in Seattle, Washington, is presented. Sampling methods included continuous area monitoring, grab sampling, personal sampling, and time study observation. A total of 27 workers were observed and monitored for solvent exposure. Short-term peak exposures were characterized in terms of magnitude, duration and repetition, and their contribution to time weighted average (TWA) exposures were evaluated. A health questionnaire addressing the symptoms potentially attributable to solvents was used to investigate the possible health effects from exposure. Significant differences in the prevalence of headaches, dizziness, intoxication, and dry skin (p < 0.01) were reported among workers who had some solvent exposure compared with the referent group that was not exposed. Exposed workers were also more likely to report fatigue, loss of strength in the arms and hands, difficulty concentrating, sore throat, and a low alcohol tolerance. The study documented highly variable levels of solvent exposures. Screen printing workers in different companies, while performing the same basic tasks, had time weighted average (TWA) exposures ranging from 2% to 100% of the recommended threshold limit value (TLV) for mixtures. Continuous monitoring indicated that high short-term exposures are responsible for the bulk of TWA exposures. Grab samples and continuous monitoring verified that recommended Short Term Exposure Limits (STEL) for individual solvents may be exceeded on a routine basis. Frequent skin contact with solvents was also observed. Health problems in this industry and other small industries using organic solvents may result from these complex patterns of exposure.

Air Pollution, Indoor↗

PubMed2001

Tractor driving among kentucky farm youth: results from the farm family health and hazard surveillance project.

This article documents the extent of children's involvement in tractor operations among a representative sample of Kentucky children living and working on family farms. Specifically, we describe children's exposures to tractor-related work activities, profile their use of the tractor (number of days worked), and assess compliance with generally recommended safety measures, such as using tractors equipped with ROPS (rollover protective structures), avoiding riding as passengers on tractors, and operating tractors on public roadways. Data for this study were collected in 1994 and 1995 as part of the NIOSH-sponsored Farm Family Health and Hazard Surveillance Project (FFHHSP). Despite recognition in the health and safety community of the hazards associated with operating tractors without ROPS on public roadways and with extra riders, these practices remain common among youth on Kentucky farms. Farms with annual incomes greater than $10,000, particularly with livestock commodities, appear to use youth for a greater number of days of tractor operation than other farms. Such farms may be an appropriate target for intervention.

Accidents, Occupational↗

PubMed2000

Chronic arsenic exposure and risk of infant mortality in two areas of Chile.

Chronic arsenic exposure has been associated with a range of neurologic, vascular, dermatologic, and carcinogenic effects. However, limited research has been directed at the association of arsenic exposure and human reproductive health outcomes. The principal aim of this study was to investigate the trends in infant mortality between two geographic locations in Chile: Antofagasta, which has a well-documented history of arsenic exposure from naturally contaminated water, and Valparaíso, a comparable low-exposure city. The arsenic concentration in Antofagasta's public drinking water supply rose substantially in 1958 with the introduction of a new water source, and remained elevated until 1970. We used a retrospective study design to examine time and location patterns in infant mortality between 1950 and 1996, using univariate statistics, graphical techniques, and Poisson regression analysis. Results of the study document the general declines in late fetal and infant mortality over the study period in both locations. The data also indicate an elevation of the late fetal, neonatal, and postneonatal mortality rates for Antofagasta, relative to Valparaíso, for specific time periods, which generally coincide with the period of highest arsenic concentration in the drinking water of Antofagasta. Poisson regression analysis yielded an elevated and significant association between arsenic exposure and late fetal mortality [rate ratio (RR) = 1.7; 95% confidence interval (CI), 1.5-1.9], neonatal mortality (RR = 1.53; CI, 1.4-1.7), and postneonatal mortality (RR = 1.26; CI, 1.2-1.3) after adjustment for location and calendar time. The findings from this investigation may support a role for arsenic exposure in increasing the risk of late fetal and infant mortality.

Arsenic↗

PubMed2000

A database analysis of potentially inappropriate drug use in an elderly medicaid population.

We conducted a cross-sectional retrospective review of 1996 Kentucky Medicaid Pharmacy claims data to examine the prevalence of potentially inappropriate drug use in 64,832 Medicaid recipients aged 65 years and older who received a prescription. Twenty-seven percent of patients received at least one potentially inappropriate agent. Prevalence was higher for nursing home residents (33%) than for community dwellers (24%). Amitriptyline (7.6%), propoxyphene (6.5%), doxepin (4.0%), and indomethacin (2.3%) were the most prescribed potentially inappropriate agents. Education programs and interventions aimed at optimizing the prescribing and dispensing of the most appropriate drugs are needed.

Aged↗

PubMed2000

Sex differences in principal farm operators' tractor driving safety beliefs and behaviors.

OBJECTIVE: To examine the widely accepted hypothesis that farm women are more concerned with safety issues and behaviors than their male counterparts are. METHODS: A telephone survey was administered to a random sample of Kentucky principal farm operators, 90 of whom were women. Participants were questioned about their tractor safety beliefs and practices. RESULTS: No significant sex differences in tractor safety perceptions and behavior were observed. CONCLUSIONS: Socialization of women to the role of principal farm operator may override their typically greater sensitivity to safety issues, an important consideration when designing safety campaigns for this population.

Adult↗

PubMed2000

Positive predictive value of cardiac fluoroscopy in asymptomatic U.S. Army aviators.

The primary aim of this study was to determine the positive predictive value (PPV) of cardiac fluoroscopy in U.S. Army aviators. Cardiac fluoroscopy is one of the non-invasive tests used to screen for coronary artery disease (CAD) in the U.S. Army Cardiovascular Screening Program. The secondary objective is to determine the positive predictive value (PPV) of the combination of the aeromedical graded exercise test (GXT) and cardiac fluoroscopy. The results of these two screening tests are used to determine the need for coronary angiography. Records of 220 male aviators (mean age--42.3) who underwent coronary angiography from 1990-95 were obtained from the Aviation Epidemiology Data Register (AEDR) at Ft. Rucker, AL. These records contained results from the screening tests (GXT, cardiac fluoroscopy, and thallium scintigraphy) and coronary angiography. Significant CAD (SCAD) was present in 47 (21%), while 83 (38%) had minimal CAD (MCAD). The PPV of cardiac fluoroscopy was 81% for all CAD (34% for SCAD). GXT and thallium scintigraphy had a PPV of 62 and 67% for all CAD (23 and 45% for SCAD), respectively. The PPV's of the screening tests were not statistically different at the 95% confidence interval level. The combination of GXT and cardiac fluoroscopy had a PPV of 64% (21% for SCAD).

Adult↗

PubMed1998

Agricultural injuries among older Kentucky farmers: The Farm Family Health and Hazard Surveillance Study.

This population-based study reports the cumulative incidence of agricultural injuries during a 1-year period in a sample of 998 farmers aged 55 years and older living in Kentucky. A total of 98 farm-related injuries were reported among 88 older farmers for a crude injury rate of 9.03 injured farmers per 100 farmers (95% confidence interval (CI) = 7.03-11.03) over a 1-year period. The leading external causes of farm injury were falls (24.9%), machinery (22.5%), wood-cutting (14.6%), and animal-related events (14.3%). Farmers working on farms with beef cattle (alone) (odds ratio = 1.90; 95% CI = 1.02-3.55) or farms with beef cattle and tobacco (odds ratio = 2.15; 95% CI = 1.00-4.59) had a statistically significant increased risk for a farm-related injury. Farmers reporting a prior injury that limited their ability to farm were at increased risk for a farm-related injury. Approaches to using farm injury surveillance data for injury control programs in the state are discussed.

Accidents, Occupational↗

PubMed1997

Social support, stress, and blood pressure in black adults.

Psychosocial factors arising from socioeconomic disadvantage and discrimination may contribute to the excess risk of elevated blood pressure in African-Americans. The purpose of this study was to assess the association of social support and stress with blood pressure in a community-based sample of 25-to 50-year-old black adults in Pitt County, NC. A stratified random sample of dwellings was selected in 1988, and 1,784 black adults (80% of those eligible) were interviewed. Analyses were sex specific and adjusted for age, obesity, and waist/hip ratio. In separate analyses of emotional support, instrumental support, and stress with blood pressure, all associations were in the predicted direction (inverse for support, direct for stress) but were stronger for systolic than for diastolic blood pressure. Differences in systolic blood pressure associated with low support or high stress ranged from 5.2 to 3.6 mmHg in women and 3.5 to 2.5 mmHg in men. In simultaneous regression analyses of support and stress, each of the separate effects was reduced for women, but a sizable aggregate effect of low support and high stress remained [+7.2 mmHg (95% confidence limits = +1.3, +13.1) for systolic blood pressure and +4.0 mmHg (95% confidence limits = +0.1, +7.9) for diastolic blood pressure.

Adult↗

PubMed1997

Cancer mortality among electric utility workers exposed to polychlorinated biphenyls.

OBJECTIVES: To assess whether excess mortality from cancer, malignant melanoma of the skin, and cancers of the brain and liver in particular, is associated with long term occupational exposure to polychlorinated biphenyls (PCBs). METHODS: An epidemiological study of mortality was conducted among 138,905 men employed for at least six months between 1950 and 1986 at five electrical power companies in the United States. Exposures were assessed by panels composed of workers, hygienists, and managers at each company, who considered tasks performed by workers in 28 job categories and estimated weekly exposures in hours for each job. Poisson regression was used to examine mortality in relation to exposure to electrical insulating fluids containing PCBs, controlling for demographic and occupational factors. RESULTS: Neither all cause nor total cancer mortality was related to cumulative exposure to PCB insulating fluids. Mortality from malignant melanoma increased with exposure; rate ratios (RRs) relative to unexposed men for melanoma were 1.23 (95% confidence interval (95% CI) 0.56 to 2.52), 1.71 (0.68 to 4.28) and 1.93 (0.52 to 7.14) for men with < 2000, > 2000-10,000, and > 10,000 hours of cumulative exposure to PCB insulating fluids, respectively, without consideration of latency. Lagging exposure by 20 years yielded RRs of 1.29 (0.76 to 2.18), 2.56 (1.09 to 5.97), and 4.81 (1.49 to 15.50) for the same exposure levels. Mortality from brain cancer was modestly increased among men with < 2000 hours (RR 1.61, 95% CI 0.86 to 3.01) and > 2000-10,000 hours exposure (RR 1.79, 95% CI 0.81 to 3.95), but there were no deaths from brain cancer among the most highly exposed men. A lag of five years yielded slightly increased RRs. Mortality from liver cancer was not associated with exposure to PCB insulating fluids. CONCLUSIONS: This study was larger and provided more detailed information on exposure than past investigations of workers exposed to PCBs. The results suggest that PCBs cause cancer, with malignant melanoma being of particular concern in this industry.

Follow-Up Studies↗

PubMed1997

Triazine herbicide exposure and breast cancer incidence: an ecologic study of Kentucky counties.

The incidence of breast cancer in the United States has steadily increased for the past three decades. Exposure to excess estrogen, in both natural and synthetic forms, has been implicated as a risk factor for the development of this disease. Considerable interest has been focused on organochlorines, such as the triazine herbicides, and their possible role in the initiation or promotion of human breast cancer. To explore this relationship, an ecologic study of Kentucky counties was designed. Exposure to triazines was estimated by use of water contamination data, corn crop production, and pesticide use data. A summary index of triazine herbicide exposure was developed to classify counties into low, medium, or high exposure levels. Data on county breast cancer rates were obtained from the state registry. A Poisson regression analysis was performed, controlling for age, race, age at first live birth, income, and level of education. Results revealed a statistically significant increase in breast cancer risk with medium and high levels of triazine exposure [odds ratio (OR) = 1.14,p<0.0001 and OR = 1.2, p<0.0001, respectively]. The results suggest a relationship between exposure to triazine herbicides and increased breast cancer risk, but conclusions concerning causality cannot be drawn, due to the limitations inherent in ecologic study design.

Adult↗

PubMed1994

Organization and classification of work history data in industry-wide studies: an application to the electric power industry.

Industry-based cohort studies require systems for organizing work history data. Although the ultimate goal may be to assess the hazards of specific exposures, classification of the job titles that comprise work histories serves an important descriptive purpose in itself and is often necessary before exposure data can be obtained. A system we have created for organizing jobs in a study of 135,000 workers at five electric power companies highlights conceptual and practical issues in managing work history data for epidemiological studies. Job characteristics including function, location, and authority were used to develop a system of 28 occupational categories. Comprehensibility, flexibility, and efficiency were important criteria in designing the system. Assessment of exposures was an implicit goal; the same categories will define job-exposure matrices for numerous agents. A combination of computer algorithms and expert judgment was used to assign individual job titles to the categories. This system facilitates examining the effects of various agents and controlling for confounding. The 28 categories can be collapsed and regrouped to analyze disease risks in relation to exposures to magnetic fields and other agents; even exposures not previously considered could be brought into the study with this generic system for organizing the electric power industry.

Data Collection↗

PubMed1992

Socioeconomic status, John Henryism, and blood pressure in black adults. The Pitt County Study.

The joint influence of socioeconomic status and John Henryism on blood pressure was examined in a probability sample of 1,784 black adults aged 25-50 years in Pitt County, North Carolina, in 1988. John Henryism was measured by means of the John Henryism Active Coping Scale. Socioeconomic status (low, medium, and high) was based on respondents' education and occupation. Prior research indicated that, for blacks, the inverse association between socioeconomic status and hypertension may be stronger for individuals who score high in John Henryism. In this more urban sample of blacks, the hypothesized interaction achieved modest statistical support (p less than 0.08) only for hypertension prevalence. For individuals with high levels of John Henryism, adjusted prevalences declined with increasing socioeconomic status (29.4%, 26.2%, and 20.5% for low, medium, and high socioeconomic status, respectively); for individuals with low levels of John Henryism, hypertension prevalence was similar in the low (22.6%) and medium (22.8%) socioeconomic categories but higher in the high socioeconomic category (25.9%). Elevated psychological stress in white-collar workers was probably responsible for the nonsignificant inverse gradients between socioeconomic status and mean blood pressures and for the weak interaction between socioeconomic status and John Henryism with regard to hypertension prevalence.

Adaptation, Psychological↗

PubMed1991

Alcohol consumption and blood pressure in black adults: the Pitt County Study.

While there is a clear consensus in the epidemiologic literature on the direct association between alcohol consumption and blood pressure, the shape of this relation and its strength in blacks are uncertain. Therefore, the association between alcohol and blood pressure was examined in a community-based random sample of 1,784 black adults aged 25 to 50 years living in eastern North Carolina. These individuals were interviewed in 1988 for a study of psychosocial and dietary risk factors for elevated blood pressure. Alcohol consumption was estimated from responses to a food frequency questionnaire and was divided into four categories, which ranged from abstention (52% of the sample) to greater than or equal to seven drinks/week (12%). After adjustment for age and body mass, the systolic blood pressure of adults reporting greater than or equal to seven drinks/week exceeded that of nondrinkers by 6.8 mmHg for men and women (p less than 0.001). There was no evidence of a threshold effect, and similar patterns were observed for diastolic blood pressure. Being in the highest category of alcohol consumption was related to low socioeconomic status, lower social integration, and higher levels of socioeconomic stressors. These data are consistent with a graded association between alcohol and blood pressure in black adults and suggest the importance of social factors underlying this association.

Adult↗

PubMedDate not supplied

Farm tractor safety in Kentucky, 1995.

OBJECTIVE: Tractor rollovers are a major cause of farm injuries and fatalities. The authors used data from a statewide surveillance study to estimate the prevalence of safety features such as rollover protective structures, seat belts, and power take-off shields on farm tractors in Kentucky. METHODS: Using data from the Farm Family Health and Hazard Surveillance Project, the authors report on the prevalence of farm tractor safety features by size of farm, by region of the state, by number of tractors per farm, and by tractor age and estimate the prevalence of tractors equipped with rollover protection by region and for the state as a whole. RESULTS: Of the estimated 85,446 family-owned farms in Kentucky with at least one tractor, an estimated 55.6%, or 47,515 farms, do not have a tractor equipped with a rollover protective structure. Few tractors that are 10 years old or older were found to be equipped with seat belts; no tractors that were more than 20 years old were equipped with seat belts. CONCLUSIONS: Kentucky, with an estimated 25 to 30 tractor-related fatalities each year, may contribute up to 20% of the total number of farm tractor fatalities in the nation. The overall prevalence of rollover protective structures on tractors in Kentucky is lower than estimates for other states as reported in national survey data. The study's findings suggest the need to target smaller farms with one or two tractors for retrofitting of rollover protective structures and for tractor safety programs.

Accidents, Occupational↗