Paul S. Whitten

Fatal motor vehicle crashes in rural and urban areas: decomposing rates into contributing factors

Objectives: Motor vehicle crash fatality rates have been consistently higher in rural areas than in urban areas. However, the explanations for these differences are less clear. In this study the decomposition method was used to explore the factors associated with increased fatal crash involvement rates in rural communities. Design: Using national databases, the fatal crash incidence density was decomposed into the product of three factors: the injury fatality rate, the crash injury rate, and the crash incidence density. Results: As expected, the fatal crash incidence density was more than two times higher in rural than in urban areas. This was driven primarily by the injury fatality rate, which was almost three times higher in rural areas. Conclusions: Further research should examine the relative roles of crash severity and the timely receipt of definitive medical care after a crash.

A Control Study of the Physical and Mental Health of Residents Living Near a Large-scale Swine Operation

This article presents the results of a study assessing the physical and mental health of residents living in the vicinity of a large-scale swine confinement operation. Physical and mental health data were collected via personal interviews from a sample (n = 18) of all neighbors living within a two-mile radius of a 4,000-sow swine production facility. Results were compared to similar data collected from a random sample of demographically comparable rural residents (n = 18) living near minimal livestock production. Results indicate that neighbors of the large-scale swine operation reported experiencing significantly higher rates of four clusters of symptoms known to represent toxic or inflammatory effects on the respiratory tract. These clusters of symptoms have been well-documented among swine confinement workers. There was no evidence to suggest that neighbors of the large-scale swine operation suffered higher rates of psychological health problems manifested as anxiety or depression. A larger population-based study is needed to test the hypothesis that neighbors of large-scale swine operations experience elevated rates of physical health symptoms comparable to interior confinement workers.

Indoor Environmental Quality in Six Commercial Office Buildings in the Midwest United States

The aims of this study were to characterize physical, mechanical, and environmental factors influencing indoor environmental quality (IEQ) in commercial office buildings; document occupant perceptions and psychosocial attributes; and evaluate relationships among these parameters. Six large office buildings in metropolitan areas were selected in Iowa, Minnesota, and Nebraska. Comprehensive sampling was conducted over one week in each building, during all four seasons. This paper presents the study methods and selected results from the first round of sampling (November 1996 to April 1997). Air flow and recirculation rates were quite variable, with the proportion of outdoor air provided to occupants ranging from 10 to 79 CFM/person. Carbon dioxide, carbon monoxide, and temperature were within ranges anticipated for nonproblem buildings. Relative humidity was low, ranging from 11.7 to 24.0 percent. Indoor geometric mean concentrations of total volatile organic compounds (TVOCs) ranged from 73 to 235 microg/m3. The most prevalent compounds included xylene, toluene, 2-propanol, limonene, and heptane. Geometric mean formaldehyde concentrations ranged from 1.7 to 13.3 microg/m3, and mean acetaldehyde levels ranged from <3.0 to 7.5 microg/m3. Airborne concentrations of culturable bacteria and fungi were low, with no samples exceeding 150 CFU/m3. Total (direct count) bioaerosols were more variable, ranging from 5010 to 10,700 organisms/m3. Geometric mean endotoxin concentrations ranged from 0.5 to 3.0 EU/m3. Respirable particulates (PM10) were low (14 to 36 microg/m3). Noise levels ranged from 48 to 56 dBA, with mean light values ranging from 200 to 420 lux. Environmental parameters were significantly correlated with each other. The prevalence of upper respiratory symptoms (dry eyes, runny nose), central nervous system symptoms (headache, irritability), and musculoskeletal symptoms (pain/stiffness in shoulders/neck) were elevated compared to other studies using similar questionnaires. Importantly, psychosocial factors were significantly related to increased symptoms in females, while environmental factors were more closely correlated with symptoms in males. Endotoxin concentrations were associated with symptoms in both males and females. These data will help to identify and quantify the relative role of factors that contribute to sick building syndrome. The data collected in this study may also be used to evaluate the effectiveness of current building operation practices, and can be used to prioritize allocations of resources for reduction of risk associated with IEQ complaints.

Work‐related injuries among Iowa farm operators: An analysis of the Iowa Farm Family Health and Hazard Surveillance Project

In 1994, the Iowa Farm Family Health and Hazard Surveillance Project carried out a two-stage, stratified, cluster survey of Iowa farms using a mail survey. With data from this representative sample of Iowa farmers, we examined the associations between farm-work-related injuries and possible risk factors for 390 principal farm operators. Forty (10.3%) of these operators reported being injured while doing farm work. We developed a logistic regression to assess associations between potential risk factors and injury. We found three factors significantly associated with injury: younger age (odds ratio [OR] = 3.1, confidence interval [CI] = 1.1-9.3), having an impairment or health problem that limits work (OR = 2.4, CI = 1.5-3.8), and hand or arm exposure to acids or alkalis (OR = 2.6, CI = 1.1-5.9). In the univariate analysis, safety training did not seem to protect farmers from injuries.

Preschool peer perceptions of the behavior of hyperactive and aggressive children

To assess if preschool children can successfully identify externalizing symptomatic behaviors in their male classmates, and if these perceptions are associated with peer-rated popularity and rejection, 154 preschool boys and girls were interviewed using a peer nomination procedure. Behavioral data on the same preschool boys (N=86) were also provided by their respective teachers. Preschool children were capable of providing stable nominations of popularity, rejection, and aggression, boys and girls significantly agreed in their nominations, and these nominations were not a function of the age of the rated child, although they differed somewhat as a function of the age of the rater. Teachers and peers reflected significant convergence in ratings of hyperactivity and aggression and teacher ratings of peer problems significantly agreed with actual peer nominations of popularity and rejection. Boys nominated as aggressive were more rejected by their classmates, whereas boys nominated as hyperactive were either more popular and /or more rejected. Limited evidence for differential patterns of relationships among hyperactivity, aggression, and peer status was obtained for both the peer and teacher data.

Comparison of Endotoxin Exposure Assessment by Bioaerosol Impinger and Filter-Sampling Methods

ABSTRACT Environmental assessment data collected in two prior occupational hygiene studies of swine barns and sawmills allowed the comparison of concurrent, triplicate, side-by-side endotoxin measurements using air sampling filters and bioaerosol impingers. Endotoxin concentrations in impinger solutions and filter eluates were assayed using theLimulus amebocyte lysate assay. In sawmills, impinger sampling yielded significantly higher endotoxin concentration measurements and lower variances than filter sampling with IOM inhalable dust samplers. Analysis of variance for repeated measures showed that this association remained after controlling for other factors such as replicate, sawmill, sawmill operation, wood type, and interaction terms. Endotoxin concentrations in the swine barns were 10-fold higher on average than in sawmills. These samples demonstrated comparable endotoxin concentration estimates for impinger and filter methods although the variability was lower using the impinger method. In both occupational settings, side-by-side replicates were more uniform for the impinger samples than for the filter samples. This study demonstrates that impinger sampling is an acceptable method for quantitation of area endotoxin concentrations. Further, when sampling is performed with impingers for airborne microorganism quantitation, these same impinger solutions can yield valid endotoxin exposure estimates, negating the need for additional filter sampling.

Risk Factors for Agricultural Injury: A Case–Control Analysis of Iowa Farmers in the Agricultural Health Study

The purpose of this case-control study nested in the Agricultural Health Study was to assess risk factors for agricultural injury among a large group of Iowa farmers. A questionnaire sent to 6,999 farmers identified 431 cases who had a farm work-related injury requiring medical advice/treatment in the previous year and 473 controls who had no injury in the previous year. We assessed several potential risk factors for injury. A multiple logistic regression analysis showed significant associations between farm work-related injury and weekly farming work hours (> or = 50 hours/week) (OR = 1.65; 95% CI = 1.23-2.21), the presence of large livestock (OR = 1.77; 95% CI = 1.24-2.51), education beyond high school (OR = 1.61; 95% CI = 1.21-2.12), regular medication use (OR = 1.44; 95% CI = 1.04-1.96), wearing a hearing aid (OR = 2.36; 95% CI = 1.07-5.20), and younger age. These results confirm the importance of risk factors identified in previous analytic studies and suggest directions for future research in preventive intervention strategies to reduce farm work-related injuries.

Field Evaluation of Endotoxin Air Sampling Assay Methods

This study tested the importance of filter media, extraction and assay protocol, and bioaerosol source on the determination of endotoxin under field conditions in swine and poultry confinement buildings. Multiple simultaneous air samples were collected using glass fiber (GF) and polycarbonate (PC) filters, and these were assayed using two methods in two separate laboratories: an endpoint chromogenic Limulus amebocyte lysate (LAL) assay (QCL) performed in water and a kinetic chromogenic LAL assay (KQCL) performed in buffer with resistant-parallel line estimation analysis (KLARE). In addition, two aqueous filter extraction methods were compared in the QCL assay: 120 min extraction at 22 degrees C with vigorous shaking and 30 min extraction at 68 degrees C with gentle rocking. These extraction methods yielded endotoxin activities that were not significantly different and were very highly correlated. Reproducibility of endotoxin determinations from duplicate air sampling filters was very high (Cronbach alpha all > 0.94). When analyzed by the QCL method GF filters yielded significantly higher endotoxin activity than PC filters. QCL and KLARE methods gave similar estimates for endotoxin activity from PC filters; however, GF filters analyzed by the QCL method yielded significantly higher endotoxin activity estimates, suggesting enhancement of the QCL assay or inhibition of the KLARE asay with GF filters. Correlation between QCL-GF and QCL-PC was high (r = 0.98) while that between KLARE-GF and KLARE-PC was moderate (r = 0.68). Analysis of variance demonstrated that assay methodology, filter-type, barn-type, and interactions between assay and filter-type and between assay and barn-type were important factors influencing endotoxin exposure assessment.

Workforce participation by persons with disabilities: the National Health Interview Survey Disability Supplement, 1994 to 1995.

Using the National Health Interview Survey Disability Supplement of 1994 to 1995, we examined the factors associated with employment among Americans with disabilities. Persons with disabilities who were more educated were more likely to be working. Married men were more likely to work than unmarried men (odds ratio [OR], 1.58). Blacks were less likely to work than whites (OR, 0.56). Persons with disabilities related to cardiovascular disease (OR, 0.23), musculoskeletal disease (OR, 0.37), and respiratory disease (OR, 0.23) were less likely to work than other Americans with disabilities. Among persons with psychiatric disorders, there was considerable variety in the propensity to work. Persons with schizophrenia (OR, 0.24) and paranoid delusional disorder (OR, 0.34) were markedly less likely to work; persons with bipolar disorder (OR, 0.60) and major depression (OR, 0.69) were also less likely to work. Lastly, persons with self-reported alcohol abuse (OR, 1.30) were more likely to work, and persons with self-reported drug abuse (OR, 0.93) were not less likely to work, than others in our study population of Americans with disabilities.

Depressive symptoms as a risk factor for unintentional injury: a cohort study in a rural county.

Objective: The authors used data from a population based prospective cohort study to determine if depressive symptoms predicted incidence of unintentional injury. Methods: The Keokuk County Rural Health Study, based in Iowa, is a prospective cohort study of health status that includes injury outcomes. Depressive symptoms were measured using the 11-item Center for Epidemiologic Studies Depression Scale at the beginning of the study on 1493 participants. Quarterly follow up phone calls were made to measure injury incidence. Results: 471 injuries were reported for an overall injury rate of 9.8 per 100 person-years. Crude injury rates were significantly higher for those with depressive symptoms (p = 0.0003). Those with depressive symptoms had a 41% increased risk for injury after controlling for antidepressant medication use, gender, prior injury, income, and sleepiness (RR = 1.41, 95% CI 1.10 to 1.80). Depressive symptoms remained a risk factor for injury regardless of current antidepressant medication use (no medication use, RR = 1.43, 95% CI 1.09 to 1.88; medication use, RR = 1.31, 95% CI 0.76 to 2.26). Conclusions: Depressive symptoms were found to be risk factors for unintentional injury. Medical practitioners should consider talking about safety with their patients, especially those reporting symptoms of depression, and recognize that an increased risk for injury remains until the depressive symptoms subside.