David Van Sickle, PhD
Much more is known about asthma among rural populations of low and middle income countries than in the United States, where attention has focused on asthma as a problem of urban areas. Studies examining differences in lifestyles and environmental exposures between urban and rural populations in Africa or Europe, for example, have played a major role in the development of our theories of the origins of asthma and in the conception of novel preventive approaches. The evidence from these comparisons has tended to support the idea that asthma parallels processes of westernization and modernization, and that rural environmental exposures may play an important protective role in the etiology of asthma.
Until last year, very little was known about asthma in the rural United States. A limited number of studies had suggested that the prevalence of asthma and asthma symptoms might be unexpectedly high, but there were few representative estimates of the overall burden. Targeted studies pointed to a number of exposures, prevalent among rural, agricultural residents, in particular. For example, studies of farm workers in California in the Farmer Health Study (http://agcenter.ucdavis.edu/research/FHS/home.php), showed that exposures to agricultural dusts was associated with the development or persistent wheeze. Reports from the Agricultural Health Study suggested that exposure to pesticides was associated with the development of asthma in women. Other reports have provided evidence that community exposures to airborne waste from large scale animal agriculture might also be associated with exacerbations of asthma.
In 2009, scientists at the Air Pollution and Respiratory Health Branch at the US Centers for Disease Control and Prevention in Atlanta, published the first comprehensive review of asthma among rural and urban residents in the US. According to Teresa Morrison, MD, MPH, the lead author of this study, “This work showed that asthma-related morbidity may be a seriously underestimated public health priority in rural areas, and that strategic activities to improve asthma management are urgently needed.”
On the heels of that report, and to shed more light on the emerging problem of rural asthma, this past spring we worked with CDC to learn more about the patterns of asthma among rural residents in the Midwest. Our objective was to describe the frequency, patterns and geographic distribution of asthma morbidity (as captured by asthma symptoms and medication use) among adults. We began enrolling participants in March and included individuals from a total of twelve states.
To identify when and where participants were experiencing asthma symptoms, we provided each one with a device to track the time and location where they use their rescue inhaler. This small, battery powered device, is attached to their regular medication. It uses a global positioning system (GPS) receiver to determine where and when the inhaler is used and then sends that information to a remote database, This device takes advantage of the fact that nearly everyone with asthma is prescribed a medication (albuterol) that they carry around with them and use to relieve symptoms as and when they occur. We also asked participants to complete monthly surveys throughout the study period, which we used to track their exposures, and their asthma control and management and health care utilization.
The data collection phase of the project finished at the end of August. Overall we collected information on more than 1,600 inhalation events over the course of the study period, together with monthly information about changes in asthma control and management over the study period. We’ve learned a lot over the months from each of the people involved and are beginning the process of reviewing and analyzing all the information that’s been collected. Our first goal is to describe patterns of asthma symptoms and management among this population. The data from the devices will offer the first objective window on the frequency, timing and location of asthma symptoms among this group of volunteers, and will reveal a new side to rural asthma and the origins and triggers of the disease in general.
Note: We expect to present initial results from the project at scientific conferences next year. In the meantime, to learn more about our work, please visit us online (http://asthmapolis.com), on Facebook (http://www.facebook.com/pages/Asthmapolis/116175951727326), or Twitter (@asthmapolis).
David Van Sickle, PhD is co-founder and CEO of Asthmapolis, a Madison, WI company developing tools to help patients, physicians and public health better understand and manage asthma. He previously served as an Epidemic Intelligence Service officer at the US Centers for Disease Control and Prevention, and as a Robert Wood Johnson Foundation Health and Society Scholar at the University of Wisconsin – Madison.