Great Plains Center for Agricultural Health

Center-funded Research

Musculoskeletal Disorders Among Farmers

Nathan Fethke, PhD

Given the large size of the agricultural workforce and the elevated rate of injury and illness compared to other industries, surprisingly few studies are available in the peer-reviewed literature examining associations between agricultural activities and musculoskeletal outcomes. Inferences from this literature are limited by several methodological weaknesses, including small sample sizes, cross-sectional study design, and poor estimation of exposure to physical risk factors.

The primary objective of this project is to provide new information about associations between exposure to physical risk factors and musculoskeletal symptoms among agricultural workers. We will follow a prospective cohort and assess musculoskeletal symptom status more frequently than in previous studies. In addition, we will use direct measurement methods to estimate exposure during common agricultural activities. This approach improves upon previous epidemiologic studies of musculoskeletal outcomes among agricultural workers, which are predominately cross-sectional in design with relatively rudimentary exposure estimates. Our project will provide a more complete understanding of the associations between physical risk factors and musculoskeletal symptoms and will guide future intervention and prevention efforts.

We will address the following specific aims:

  • Examine seasonal trends of low back, neck/shoulder, and distal upper extremity musculoskeletal symptoms among agricultural workers in nine rural Midwest states.
  • Characterize exposure to physical risk factors for low back, neck/shoulder, and distal upper extremity musculoskeletal symptoms among agricultural workers in nine rural Midwest states.
  • Estimate associations between physical risk factors and low back, neck/shoulder, and distal upper extremity musculoskeletal symptoms among agricultural workers in nine rural Midwest states.

This project is a three-year, repeated-measures prospective study with a stratified, random sample of 800 agricultural workers. Mailed questionnaires will be administered at baseline and every six months during follow-up. Demographics and farm characteristics will be ascertained at baseline. Follow-up questionnaires will be used to collect information personal health, common agricultural activities, and musculoskeletal symptoms. In addition, an on-farm assessment of exposure to physical risk factors will be performed for a subsample of participants.

Farm Equipment Crash Study

Marizen Ramirez, PhD

Rural roads are not traditionally designed for slow-moving large vehicles/equipment. With increasing urbanization, farm equipment/vehicles are increasingly sharing rural roads with non-agricultural motor vehicles. Crashes involving farm equipment/vehicles are a persistent risk in the Midwestern U.S., but the patterns of these crashes and subsequent injuries are not well-understood. In particular, very little is known about the impact of rural roadway safety legislation and engineering design on these crashes and their injuries. The overall goal of this project is to better understand the causes of these crashes and to disseminate this knowledge in order to prevent them.

The aims of this project are to 1) determine if farm equipment/vehicle crash rates vary across nine states, and if rates are higher among states with the least strict marking and lighting policies, 2) identify individual, crash and environmental risk factors for farm equipment/vehicle crashes and subsequent injuries, 3) determine if operators of farm equipment/vehicles with citations for marking and lighting have increased risk for crashes and crash-related injuries, and 4) using Geographic Information Systems, identify high frequency locations for these crashes and which roadway factors are associated with crashes.

We will use existing surveillance data on public roadway crashes from nine Midwestern States (IA, IL, KS, MN, MO, NE, ND, SD, WI) across eight years, collect data on lighting and marking legislation in these states, and conduct a driving exposure survey with the assistance of the National Agricultural Statistics Service (NASS). At the end of the study, we will engage in strategic planning with a rural roadway task force and stakeholders from the nine states. This study has important implications for rural roadway policy and engineering design.

Intervention to Reduce Exposures in CAFOs

T Renee Anthony, PhD

Workers in concentrated animal feeding operations (CAFO) are at risk of adverse respiratory outcomes. This project focuses on adapting industrial exposure control techniques (ventilation) for use in CAFOs to reduce worker exposures to gases and particulates generated by these operations. The long-term objective of this work is to provide design and operation guidance of these ventilation systems, to swine producers and CAFO builders. By adapting technology optimized in this study, CAFO workers will have reduced exposures to airborne contaminants, thereby reducing the risk of developing occupational lung disease. This study focuses on only one season (winter), when ventilation is minimum to reduce heating costs, and one phase of the operation (farrowing), where workers spend proportionately longer periods in CAFO facilities than other operations, thereby having larger exposures than in other barn activities. The methods used in this study can be adapted to other operations in future studies.

This research will: (1) examine the effect of position, shape, and flow rate on supply and exhaust ventilation to rank order ventilation systems by the potential to reduce airborne contaminant concentrations within the CAFO, (2) optimize control options on exhausted air so that treated exhaust may be reintroduced into the CAFO and minimize heat losses in winter operations, and (3) combine the results from the first two steps into a system that is deployed and tested in an operating CAFO.

Once design parameters for the optimal ventilation and control system are determined from this study, future intervention studies, evaluations of improvements in health outcomes associated with reduction in CAFO concentrations can be explored. However, to convince swine producers to adopt this intervention, we must demonstrate that this control measure (1) is effective at reducing contaminant concentration, (2) does not adversely affecting production, and (3) requires minimal maintenance at a reasonable cost. This study will focus on these endpoints in order to influence future adaption of the optimized solutions resulting from this study. For a description of the baseline measurements, click here.

Keokuk County Rural Health Study: The Epidemiology of Agricultural Diseases and Injury

James Merchant, MD, DrPH

The Keokuk County Rural Health Study is a population-based, prospective study of health status and environmental exposures of a large stratified random sample of residents in one rural Iowa county. The study focuses on injury and respiratory disease. In addition, it monitors health care delivery, geriatric health, mental health, and other health outcomes. Injury and disease prevalence and incidence are investigated in relation to occupational, agricultural, and other environmental exposures. Our specific aims are to:

  • Assess the association between observed risk factors and injuries through prospective studies of participants.
  • Assess the association between observed risk factors and neurobehavioral outcomes through prospective studies of participants.
  • Assess the association between observed risk factors and measures of respiratory disease through prospective studies of participants.
  • Assess the association between observed risk factors and hearing impairment through prospective studies of participants.
  • Assess the association between observed risk factors and visual impairment through prospective studies of participants.
  • Assess measures of the agricultural and rural environment for evaluation of selected disease and injury outcomes.
  • Provide a comprehensive agricultural disease and injury data resource for students, faculty and other health professionals in Iowa. Federal Region VII, NIOSH and its network of Agricultural Health and Safety Centers, and to others, nationally and internationally, with these research interests.

The original goal was to study all consenting members of 1,000 farm, rural non-farm, and town households in each of three or four rounds of examinations over 20 years. Although the sample is stratified by residence type (farm, rural non-farm, and town), the entire county is, by definition, rural, since the largest town, Sigourney, has fewer than 2,500 residents (U.S. Census definition for rural). A large majority of adults (89% of the men and 66% of the women) have worked or are currently working on farms. Rounds 1 (1994-1998) and 2 (1999-2004) have been completed. Round 3 began in December 2006 and ended in August 2011. A final accounting of the cohort began in January 2012 and will be completed in Summer 2012.