Multiple studies have previously shown that increases in cockroach allergen are linked to a four-fold risk of asthma.
Matthew Perzanowski, PhD
The low economic income areas of New Orleans and New York City have some of highest childhood asthma burdens. At the 2018 American Academy of Allergy, Asthma & Immunology (AAAAI) Congress in Orlando, FL, Felicia A. Rabito, PhD, an epidemiologist Associate Professor at Tulane University, described strong preliminary clinically significant data supporting single intervention (cockroach bait traps) to improve asthma morbidity in New Orleans.
Matthew Perzanowski, PhD, an associate Professor of Columbia University School of Public Health presented an overview of the NYC Neighborhood Asthma and Allergy Study examining exposures leading to sensitization followed by asthma.
Rabito presented arguments in favor of single instead of multi-component interventional strategies to control asthma. This presentation was especially important and useful for physicians attending the meeting looking for guidance managing public health related to asthma.
Currently, guidelines only recommend multi-component approaches, but clinical data is weak and lacking. Multiple studies have previously shown that increases in cockroach allergen are linked to a four-fold risk of asthma. Another Baltimore study only found association with dust allergen and asthma morbidity.
Integrated pest management (IPM) focused on removal of mice and cockroaches, but this is costly and difficult to implement for high risk groups, Rabito said.
About 10 years ago a NIEHS-funded North Carolina State University study proved that over 90% of cockroaches could be killed within 3 months of putting out cockroach bait traps, and the loss of cockroach could be maintained for up to 12 months. Rabito’s team of investigators followed this protocol and got identical results. Moreover, IPM was not needed to get this effect on cockroaches.
Just 1 day before this presentation, investigators presented research from a meta-analysis of 59 intervention studies that was mostly weak or negative, showing no clinical benefit. But Rabito presented strong preliminary data in support of using cockroach bait traps as an intervention to managing asthma in low-income urban environments.
In the single component NoRoach study (n=102), insecticidal baiting was installed by community health workers in the homes of children aged 5 to 17 years old with asthma to see if cockroach reduction can result in improved asthma outcomes. They observed improvements in FEV1 and fewer days with asthma symptoms. Children with cockroach bait trap intervention had 47 fewer days with asthma symptoms over the course of a year, and FEV1 was increased.
Previous meta-analysis of 59 intervention studies did not report any clinically significant results, but this study did. Moreoever, Rabito described 1 other single intervention study that also revealed clinically significant results when eliminating mice — but only when they restricted analysis to those locations where mice allergen was reduced.
Rabito emphasized that insecticidal baiting could replace IPM, since it does not involve spraying toxic chemicals. Studies should begin to examine and consider baseline allergen levels. When asked whether there was any possibility that the cockroach was more of an association with some unknown factor and that perhaps it was not cockroach antigens that were causing problems, Rabito replied that is what her team believed, too. They currently have a manuscript under review that supports that idea.
Next, Perzanowski’s described epidemiological maps showing high correlation between the presence of cockroach allergen and asthma prevalence in New York City. He emphasized that researchers must think in terms of public health in order to reduce asthma. New York City recently passed the Asthma Free Housing Act to give New York City residents the right to live in homes free of mold, pests, and indoor health hazards.
For the large part, air pollution on the outside gets to the inside, according to Perzanowski’s measures. Moreover, areas of New York City with high asthma rates generally, but not in all areas, overlap high particulate carbon matter.
Perzanowski pointed out studies indicating no single interaction between a factor and asthma, but rather combinations of factors affecting susceptibility. When kids exposed to high cockroach allergen were separated into those with higher exposure to black carbon, only then did it became apparent kids with higher black carbon exposure had more asthma than those with lower black carbon exposure in his studies.
Families cannot always easily fix all of the structural damage contributing to increased asthma susceptibility and so the landlord must be forced to rectify these situations. Legal resources are needed to force landlords to remove pests.
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