Allergen Mitigation Strategies
Environmental Cardiopulmonary Disease Group
Early childhood exposure to indoor allergens is an important risk factor for allergic sensitization and the development of asthma. Asthma prevalence and morbidity rates are highest among individuals of low socioeconomic status living in inner-city areas. Therefore, the group conducted studies to test the feasibility and effectiveness of various interventions to reduce indoor allergen levels in inner-city homes. Since most of the available data suggests that sensitization to dust mite and cockroach allergens are important asthma risk factors and since the best methods to reduce these allergens have not been established, the group focused its initial efforts on the development of effective dust mite and cockroach allergen mitigation strategies.
Dust mite mitigation
Research indicates that placement of impermeable mattress/pillow covers together with either home or professional laundry of bedding leads to a significant reduction of mite allergens in the bed (Vojta et al., Env. Health Perspect., 2001). (http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info:doi/10.1289/ehp.01109815) Both intensive vacuuming and steam cleaning result in a significant reduction in mite allergens in carpet; however, the steam cleaning effect persists for at least eight weeks, whereas the intensive vacuuming effect is transient. Currently, the group is working on two studies targeting dust mites and dust mite allergens. Elevated relative humidity in the home is an important factor in controlling dust mites. Home building practices such as properly sized ventilation, sealed crawl spaces, exterior venting of exhaust fans and efficient use of HVAC systems could lead to reduced humidity in the home. The healthy homes study is investigating whether these building practices can reduce humidity in the home and subsequently reduce dust mite allergen exposure.
Asthmatics and others with dust mite allergies often implement strategies to avoid dust mite exposure, but lack objective evidence that their efforts are successful in reducing dust mite populations. Recently developed in-home test kits have introduced the capability to monitor the effectiveness of allergen reduction strategies by providing an affordable, simple way to measure dust mite allergens on a regular basis. The dust mite test kit study will determine if use of an in-home test kit results in decreased dust mite allergen levels in homes of children sensitive or allergic to dust mites and if use of an in-home test kit results in attitudinal and/or behavioral changes related to implementing and maintaining dust mite reduction strategies.
Studies suggest that intensive cockroach extermination and cleaning significantly reduces cockroach allergen levels in cockroach infested inner-city homes (Arbes et al., J. Allergy Clin. Immunol., 2003), Applying a novel spatial analysis method to determine cockroach and cockroach allergen distribution in homes leads to better insecticide placement. Improved cleaning leads to improved allergen mitigation. More recently, the group has shown that cockroach extermination alone (without cleaning) can effectively reduce cockroach allergen levels in low-income homes and maintain low levels of cockroach allergen for up to one year (Arbes et al., J. Allergy Clin. Immunol., 2003; Arbes et al., J. Allergy Clin. Immunol., 2004).
The group also conducted a study to confirm previous results and compare this novel method with extermination services provided by commercial pest control companies. The novel method utilizing intensive cockroach extermination was validated in this year-long study and proved to be much more effective than pest control services offered by commercial companies. The homes serviced by commercial pest control companies, also experienced reductions in the number of cockroaches in the homes, but the magnitude of the reduction was significantly lower than in the homes that received the novel treatment. The cockroach infestation remained relatively high after 12 months, and changes in cockroach allergens in homes serviced by commercial pest control companies were not different from those in untreated control homes (Sever et al., J. Allergy Clin. Immunol., 2007).
Our interventional studies have resulted in a novel cockroach remediation strategy that significantly reduces cockroach allergen levels. Future studies will provide opportunities to examine clinical benefits of the remediation program.