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Biomedical subjects

J A Merchant

Publications and source records attributed to J A Merchant.

At least 19 recordsLinked to original sources
PubMed2006

Tractor overturn concerns in Iowa: perspectives from the Keokuk county rural health study.

Agriculture remains one of the most hazardous industries in the U.S., with tractor overturns producing the greatest number of agricultural machinery-related fatalities. Rollover protective structures (ROPS) and seatbelts effectively reduce tractor overturn deaths. However, a large proportion of tractors in use in American agriculture are older tractors without ROPS and seatbelts. This article describes the tractor-related responses from participants in a population-based study conducted in Keokuk County, Iowa. This study was designed to measure rural and agricultural adverse health and injury outcomes and their respective risk factors. Questionnaires were partially developed from well-documented national surveys. Questions about agricultural machinery use, presence of safety equipment on the machinery, work practices, and attitudes about farm safety were included. Study participants on farms who owned tractors had an average of 3.1 tractors with an average age of 27 years. Only 39% of the 665 tractors had ROPS. Tractor age was associated with the presence of ROPS; 84% of tractors manufactured after 1984 were ROPS-equipped, whereas only 3% of tractors manufactured before 1960 were ROPS-equipped. ROPS-equipped tractors were significantly more common on larger farms and households with higher income. Only 4% of the farmers reported that their tractors had seatbelts and they wore them when operating their tractors. The results of this study support the findings of other studies, which indicate that many older tractors without ROPS and seatbelts remain in use in American agriculture. Until a dramatic reduction in the number of tractors in the U.S. operated without ROPS and seatbelts is achieved, the annual incidence of 120 to 130 deaths associated with tractor overturns will persist.

Accidents, Occupational↗
PubMed2005

A population based study of reporting patterns and characteristics of men who abuse their female partners.

OBJECTIVE: This study estimates the prevalence of male abusive behavior reported by men and their female partners and identifies characteristics of abusive men. DESIGN: Baseline survey from a population based cohort study of general health. SETTING: A rural county in Iowa, USA. SUBJECTS: 572 men and their cohabitating female partners. MAIN OUTCOME MEASURES: Male-to-female physical, emotional, and sexual abuse reported by either partner. RESULTS: In this cohort, 13.6% of men had performed at least one act of physical abuse and 34.9% emotional abuse. More than 45% of abusive men reported their own behaviors. Alcohol problems, antisocial personality characteristics, depressive symptoms, and financial stress were all positively associated with both physical and emotional abuse, but suicidal thoughts were less likely among abusers. CONCLUSION: Identification of common characteristics of abusive men may predict proclivity towards partner violence and barriers to behavior modification.

Adolescent↗
PubMed2003

Identification of risk factors for non-fatal child injury in a rural area: Keokuk County Rural Health Study.

OBJECTIVE: To identify risk factors for non-fatal injury among rural children. DESIGN: Cross sectional health interview survey, 1994-98. SETTING: A rural Iowa county, not adjacent to a metropolitan area. SUBJECTS: Stratified, random sample of households, including all resident children and adults. MAIN OUTCOME MEASURES: Injury episodes in the past 12 months among children aged 0-17 years and the parental and child characteristics associated with these episodes. RESULTS: Of the 621 children in participating households, 137 or 22.1% were injured during the past 12 months. Children age 5-17 on a sports team were 1.88 times (95% confidence interval (CI) 1.07 to 3.31) more likely than other children to be injured. Children age 12-17 who binge drink were 3.50 times (95% CI 1.31 to 9.50) more likely than other children to be injured. Compared with children not on sports teams, girls on teams were 2.26 times (95% CI 1.02 to 5.13) more likely while boys on teams were 1.60 times (95% CI 0.71 to 3.68) more likely to have an injury episode. Compared with children who did not binge drink, girls binge drinking were 8.11 times (95% CI 1.52 to 43.33) more likely while boys binge drinking were 2.19 times (95% CI 0.70 to 6.84) more likely to have an injury episode. CONCLUSIONS: Local studies such as this can provide useful clues regarding the etiology of injury. Some known and some new potential risk factors including behavioral aspects for childhood non-fatal injury in a very rural area were investigated. It is planned to address these cross sectional findings in future longitudinal follow up of this population.

Adolescent↗
PubMed2001

Risk factors for injury in rural Iowa: round one of the Keokuk County Rural Health Study.

BACKGROUND: Unintentional injuries represent a major cause of morbidity and mortality in rural communities. This study aimed to determine the distribution of injury risk factors in a rural Iowa community and to identify the rural subgroups at highest risk for injury. METHODS: We reported on 1583 participants, aged > or =25 years, from Round One of the Keokuk County Rural Health Study, a longitudinal panel study of a rural community. The self-reported data were collected during face-to-face interviews. RESULTS: Our data suggested that several risk factors for injury are not uniformly distributed among rural populations. Male farmers were significantly less likely to wear their seatbelts than townspeople or rural nonfarmers. However, farm women were as likely to wear seatbelts as other women. Both male and female farmers were more likely to use all-terrain vehicles than townspeople or rural nonfarmers. In contrast, townspeople were more likely to ride bicycles than either farmers or rural nonfarmers. Townspeople were less likely to have firearms in their homes than either farmers or rural nonfarmers. Farmers were most likely to have fired a gun in the last year. Male farmers aged <65 years were less than half as likely as other men the same age to report a history of alcohol abuse. Binge drinking was equally frequent among farmers, rural nonfarmers, and townspeople. CONCLUSIONS: These differences in risk behavior in a rural county suggest the possibility of targeting specific rural injury prevention interventions at those with the highest risk for dangerous behavior.

Adult↗
PubMed2001

Epidemiology of unintentional adult injury in a rural population.

BACKGROUND: The purpose of this study was to describe the frequency, characteristics, and risk factors of unintentional adult injury in a rural population. METHODS: We interviewed 1,644 adults representing an all-rural county in Iowa. Analyses used bivariate and multivariable logistic regression. RESULTS: Participants' mean age was 53 years, and 54% were women. Twenty-three percent (n = 380) of participants reported an injury during the past 12 months, of which four fifths were treated. Overexertion (25%) and falls (22%) caused nearly half the injuries. Women with high levels of depression symptoms had 1.57 times (95% confidence interval, 1.05-2.33) the prevalence of injury occurrence as did women with low levels of depression symptoms. Men with a CAGE score of 2 or more had between 0.98 and 2.56 times (according to the range of values of the relevant odds ratio 95% confidence interval) the prevalence of injury episode of men without this exposure. CONCLUSION: The association of injury occurrence with alcohol problems is consistent with prior research, but the increased prevalence of injury associated with high levels of symptoms of depression requires further study and explanation.

Adult↗
PubMed2001

Rural population survey of behavioral and demographic risk factors for loaded firearms.

OBJECTIVES: In the United States, firearm deaths are almost as frequent as motor vehicle deaths. Firearm unintentional and suicide death rates are raised in rural areas. This study examines firearm prevalence and storage practices in three different types of rural households. METHODS: Adults from a stratified random sample of 983 households in a rural Iowa county were interviewed. The chi2 test of independence was used to assess association between loaded, unlocked firearms and seven behavioral and demographic risk factors. RESULTS: Nearly 67% of respondents reported firearms in their households. Nearly 7% of households had a loaded, unlocked gun. Prevalence of firearms at home was higher while prevalence of loaded, unlocked guns was lower than reported in other surveys. Prevalence of loaded, unlocked guns in farm households, 10.5%, was about twice the level in town households, 5.5% (chi2 test, p=0.033). Having taken a gun safety course was associated with more than double the prevalence of a loaded, unlocked gun, 13.5% v 5.1% (chi2 test, p=0.001). The prevalence of loaded, unlocked guns in households with a handgun, 19.3%, was four and one half times higher than in households with a long gun only, 4.2% (chi2 test, p=0.001). Households with someone with a lifetime prevalence of alcohol abuse or dependence were about twice as likely as other households, 13.0% v 6.6% (chi2 test, p=0.004), to report having loaded, unlocked firearms. CONCLUSIONS: Anyone interested in promoting safe storage of firearms in rural homes should consider these observations.

Accidents, Home↗
PubMed2001

WORKSAFE IOWA Occupational Medicine Associates Network: a university--community partnership in occupational safety and health.

The WORKSAFE IOWA Occupational Medicine Associates Network is a unique health care model for dispensing regional occupational medicine services in the state of Iowa, USA. WORKSAFE IOWA is an educational, informational, and consultation service of the College of Public Health at The University of Iowa. WORKSAFE IOWA includes a fee-for-service industrial hygiene program, the Occupational Medicine Associates Network, and educational and informational services. The Associates Network provides education, information, and consultation in exchange for an annual fee paid by each Associate to the university-based network. The Associates clinics provide comprehensive occupational medicine services to up to 1,500 clients through 66,000 annual clinic visits in their respective communities. The Associates Network has been financially self-sustaining over a period of 10 years, and has proven to provide valuable services to the community-based Associates, and to provide excellent training opportunities for the University students in several occupational safety and health disciplines.

Community Networks↗
PubMed2000

Dose-response relationships between occupational aerosol exposures and cross-shift declines of lung function in poultry workers: recommendations for exposure limits.

Numerous articles have been published regarding the adverse respiratory health consequences of working in intensive livestock and poultry housing. Threshold limit exposure guidelines are not currently applied to this environment, but they are essential to implement and monitor effective environmental controls. Previous dose-response research work with swine workers has resulted in exposure limit recommendations of 2.5 mg/m3 total dust, 0.23 mg/m3 respirable dust, 100 EU/m3 endotoxin, and 7 ppm ammonia. No similar recommendations have been reported previously for poultry workers. Therefore, an industry-wide study was conducted to examine dose-response relationships of bioaerosol exposures and worker respiratory health. A total of 257 poultry workers were studied for respiratory symptoms, pulmonary function, and exposure to dust (total and respirable), endotoxin (respirable and total), and ammonia. Details of the sampling plan and environmental assessment are described elsewhere. Relationships between exposures and response were studied by correlation and multiple regressions. Significant dose-response relationships were observed between exposures and pulmonary function decrements over a work shift. Exposure concentrations associated with significant pulmonary function decrements were as follows: 2.4 mg/m3 total dust, 0.16 mg/m3 respirable dust, 614 EU/m3 endotoxin, and 12 ppm ammonia.

Adult↗
PubMed1998

Organic dust exposures from work in dairy barns.

Environmental surveys were conducted in 85 barns, predominantly dairy, in central Wisconsin to characterize exposures to organic dusts and dust constituents from routine barn work. Environmental analytes included airborne dusts (total, inhalable inlet, and respirable), particle size distributions, endotoxins, total spore and bacteria counts, viable bacteria and fungi, histamine, cow urine antigen, mite antigen, ammonia, carbon dioxide, and hydrogen sulfide. The geometric mean (GM) concentration of airborne dusts include area total, 0.74 mg/m3; personal inhalable inlet, 1.78 mg/m3, and area respirable, 0.07 mg/m3. Viable bacteria and fungi, spores, endotoxins, histamine, cow urine antigen, and mite antigen were quantifiable constituents of these organic dusts and potential respiratory exposure hazards from routine dairy barn work. Endotoxin concentrations from the inhalable inlet samples ranged from 25.4 endotoxin units per cubic meter of air (EU/m3) to 34,800 EU/m3. The GM endotoxin concentration from these samples, 647 EU/m3, exceeds estimated threshold exposure levels for respiratory health effects. Ammonia was a common irritant quantified in most dairy barns. There were significant correlations between the concentrations of organic dusts and certain dust constituents, although in most instances these correlations were not strong. These sampling results demonstrate the complex nature of organic dusts and provide quantitative description of the exposures to toxic and immunogenic dust constituents during routine barn work.

Air Microbiology↗
PubMed1998

Physician visits in a farming-dependent county.

Physician visits in a farming-dependent county in the upper-Midwest were studied using a mail questionnaire. A 16 percent random sample of households yielded 426 surveys (60 percent response rate). The dependent variable was the natural log (plus one) of the number of times the respondent had seen a physician in the prior 12 months. Predisposing, enabling, and medical need variables were tested as potential predictors of medical care usage. Self-rated health status proved to be an important predictor, as was a history of hospitalization and being married. However, health insurance coverage and family income were not associated with increased physician visits. Implications for modifying the conceptual model employed to analyze medical care utilization in similar populations are discussed.

Adult↗
PubMed1997

Prospective epidemiologic evaluation of laboratory animal allergy among university employees.

OBJECTIVES: Evaluation of incidence and risk factors for development of laboratory animal allergy (LAA) among new hires previously unexposed to lab animals. METHODS: Baseline, 6-month and yearly follow-up, questionnaires, pulmonary functions, and methacholine challenges were collected from 98 never-before occupationally exposed and 90 control laboratory researchers. The two groups were followed between 6 and 36 months. RESULTS: At baseline, there were no differences in atopy, pulmonary functions, or methacholine reactivity between the two groups. The incidence of work-related asthma was comparable in the two groups, approximately 2.5% at 6 months and 4.5% at 24 months. The rate of decline in FEV1 was statistically significantly greater in the animal-exposed than nonanimal-exposed workers, and animal-exposed smokers' FEV1 declined significantly more rapidly than any other groups'. CONCLUSION: Despite the low incidence of laboratory-animal allergy and work-related asthma in this group, this study corroborates previously described interaction between smoking and animal exposure.

Animal Technicians↗
PubMed1997

Assessing public health performance in Iowa's counties.

Local health agencies in Iowa were surveyed to assess the performance of public health practices in their communities. Responses were received from 97 percent of counties. Less than 50 percent of counties were performing half of the indicators of the Assessment function. Policy Development functions also were frequently not performed. Performance was best in the Assurance function, with 86 percent of counties reporting that they inform and educate the public. However, the other three types of Assurance practices (Manage, Implement, and Evaluate) were performed less frequently. Comparison of the performance of Iowa's rural counties reveals a profile nearly identical to that reported elsewhere for a group of six other states.

Benchmarking↗
PubMed1996

Longitudinal evaluation of dose-response relationships for environmental exposures and pulmonary function in swine production workers.

Studies describing respiratory health hazards for workers in swine production facilities have been published in the United States, Sweden, Canada, the Netherlands, and Denmark. Up to 50% of these workers experience bronchitis, organic dust toxic syndrome, hyper-reactive airways disease, chronic mucous membrane irritation, and other respiratory effects. These studies clearly point to the fact that this occupational environment poses a significant health risk hazard, and that control methods are needed to protect the worker. Before precise control strategies can be developed, implemented, and evaluated, dose-response studies are required to determine acceptable target levels for exposure. A previous manuscript described the development of multiple regression equations characterizing the relationships between environmental exposures and pulmonary response in a cohort of 207 swine producers. Baseline pulmonary function was included as a significant predictor of cross-shift decrements in pulmonary function in addition to personal measurements of dust, endotoxin, and ammonia concentrations. These equations were then used to predict specific exposure levels of dust and ammonia that could be expected to elicit significant decrements in cross-shift pulmonary function. This paper presents the results from analysis of follow-up data obtained on this same cohort 2 years after the initial measurements. At the second measurement period of the study (time-2), swine workers were found to have a mean cross-shift decrease in FEV1 of 2%. Cross-shift change in FEV1 was significantly correlated with personal exposures to total dust, total endotoxin, respirable endotoxin, and ammonia. The magnitude of the decrease in FEV1 was associated with increasing airborne concentrations of these environmental parameters thus confirming the dose-response relationship observed in the initial study (time-1). The correlation of dust with FEV1 changes in workers with more than 6 years of exposure (time-1 data) and more than 10 years of exposure (time-2 data) suggests that dust exposure is an important factor in chronic respiratory disease. Additionally, the correlation of endotoxins with FEV1 changes in the group with less than 6 years exposure (time-2 data) suggests endotoxins may have more significance for subacute respiratory effects. The agreement between observed cross-shift FEV1 changes measured in time-2 with changes predicted using regression equations derived from time-1 data demonstrates a consistent dose-response relationship over time for this cohort of swine production workers. This finding provides further support for conclusions of the previous study that levels of 2.5 mg/m3 (total dust) and 7.5 ppm (ammonia) are reasonable guidelines for occupational exposure limits in this environment.

Adult↗
PubMed1996

Epidemiologic assessment of laboratory animal allergy among university employees.

The prevalence of, and risk factors for, laboratory animal allergy (LAA) among university employees were evaluated in a cross-sectional university-based study. A stratified random sample was drawn based on current or no laboratory animal exposure and smoking status. Participants received a modified ATS questionnaire; spirometry; methacholine challenge; and intradermal allergen skin tests. One hundred three currently animal-exposed and 113 never-occupationally-exposed employees participated. Controlling for smoking, currently exposed workers were significantly more likely than controls to describe work-related cough, odds ratio (O.R.) = 6.87; wheeze, O.R. = 12.96; and chest tightness, O.R. = 2.89. Skin test reactivity to non-animal antigens was associated in a dose-response fashion with both upper and lower respiratory symptoms, O.R. = 1.45 and 1.65, respectively, for each additional positive skin test. Exposed workers were significantly more likely than controls to react to methacholine at either 10 or 25 mg/ml, while controlling for smoking status, prior allergy, or asthma. Multiple logistic regression analysis revealed history of hay fever, family history of allergy, non-animal skin test positivity, animal bites, age, and smoking status to each be associated with work-related respiratory symptoms. These data suggest that atopy and smoking status are risk factors for LAA symptoms. Smoking was associated with work-related respiratory symptoms among animal-exposed workers, but not with skin test positivity. It is therefore recommended that periodic screening evaluations be performed on laboratory animal workers and that workers who are atopic, are smokers, or are symptomatic be placed in low exposure settings. These data further, support the need for efficient exhaust ventilation, personal protective clothing and, among high risk workers, the use of efficient respiratory protection.

Animals↗
PubMed1996

Method to electronically collect emergency department data.

STUDY OBJECTIVE: To describe the development and completeness of an electronic injury-surveillance system, the Rural Injury Surveillance System (RISS). METHODS: The emergency departments of nine rural Iowa hospitals submitted information on all patients treated from May 1993 through June 1994. RESULTS: The EDs submitted information on 23,594 patients with 32,445 different injury, disease, or follow-up visits. On the basis of comparison with the handwritten ED logbook, 90% of visits were also available in the RISS. Of the visits recorded in the RISS, 99% were also recorded in the logbook. The proportion of missing diagnostic codes decreased from a high of 22.6% in May 1993 to 8.1% in June 1994. The proportion of missing external cause codes was about 25% at the end of the study period. The proportion of missing industry and occupational codes was less than 5% at the end of the study period. CONCLUSION: Our findings show that complete, computerized, ED-based injury surveillance in rural EDs is possible and should be developed further.

Data Collection↗
PubMed1995

Respiratory dysfunction in swine production facility workers: dose-response relationships of environmental exposures and pulmonary function.

Human respiratory health hazards for people working in livestock confinement buildings have been recognized since 1974. However, before comprehensive control programs can be implemented, more knowledge is needed of specific hazardous substances present in the air of these buildings, and at what concentrations they are harmful. Therefore, a medical epidemiological and exposure-response study was conducted on 207 swine producers using intensive housing systems (108 farms). Dose-response relationships between pulmonary function and exposures are reported here. Positive correlations were seen between change in pulmonary function over a work period and exposure to total dust, respirable dust, ammonia, respirable endotoxin, and the interactions of age-of-producer and dust exposure and years-of-working-in-the-facility and dust exposure. Relationships between baseline pulmonary function and exposures were not strong and therefore, not pursued in this study. The correlations between exposure and response were stronger after 6 years of exposure. Multiple regression models were used to identify total dust and ammonia as the two primary environmental predictors of pulmonary function decrements over a work period. The regression models were then used to determine exposure concentrations related to pulmonary function decrements suggestive of a health hazard. Total dust concentrations > or = 2.8 mg/m3 were predictive of a work period decrement of > or = 10% in FEV1. Ammonia concentrations of > or = 7.5 ppm were predictive of a > or = 3% work period decrement in FEV1. These predictive concentrations were similar to a previous dose-response study, which suggested 2.5 mg/m3 of total dust and 7 ppm of NH3 were associated with significant work period decrements. Therefore, dust > or = 2.8 mg/m3 and ammonia > or = 7.5 ppm should be considered reasonable evidence for guidelines regarding hazardous exposure concentrations in this work environment.

Adult↗