Grantee Research Project Results

2002 Progress Report: A Randomized, Controlled Trial of Home Exposure Control in Asthma

EPA Grant Number: R826724C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R826724
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for the Study of Childhood Asthma in the Urban Environment
Center Director: Hansel, Nadia
Title: A Randomized, Controlled Trial of Home Exposure Control in Asthma
Investigators: Eggleston, Peyton A.
Institution: The Johns Hopkins University
EPA Project Officer: Callan, Richard
Project Period: January 1, 1998 through January 1, 2002
Project Period Covered by this Report: January 1, 2001 through January 1, 2002
Project Amount: Refer to main center abstract for funding details.
RFA: Centers for Children's Environmental Health and Disease Prevention Research (1998) RFA Text |  Recipients Lists
Research Category: Children's Health , Human Health

Objective:

There have been no changes to the original goals of this community-based prevention project which are to conduct a randomized controlled trial of the effectiveness of current intervention methods to reduce hazardous exposures and their adverse health effects.

The intervention will test the effectiveness (efficacy and feasibility) of home environmental treatment procedures that are currently recommended and have not been rigorously tested for their ability to affect asthma morbidity. If these procedures prove effective, we will have supported an important public health measure in the long term treatment and prevention of asthma in childhood. If the procedures are not effective, we will be able to modify the procedures and conduct a similar test in the future. Since indoor allergen and pollutant exposure has been shown to be extremely important risk factor foe asthma morbidity, it is reasonable to expect that effective methods of reducing exposure will reduce asthma morbidity.

Progress Summary:

There is no preliminary data regarding outcome. During year 04 investigators continued the recruiting, evaluation, and intervention procedures that were established in year 01. Their recruiting process begins with a presentation of an asthma self-management program in five elementary schools. During year 04 they presented the program to 174 children, in 154 families; a total of 383 children have received the presentation to date. Following the program, families were visited to discuss their child's progress in the educational program and to introduce the intervention. In year 04, 64 families were willing to be approached by the interviewer, and 33 families were actually consented into the study. An additional 28 families were referred directly to the interviewer, and of these 4 were randomized in year 04. Their enrollment target of 100 randomized subjects was achieved.

Of the 100 randomized families, 50 are in the immediate intervention group and 50 are in the control group (delayed intervention). The intervention requires 3 home visits to educate the family and to install mattress and pillow encasings, room HEPA air cleaners and initiate cockroach extermination procedures where necessary. Follow-up home evaluations visits at 6 months and 12 months have been completed with a high success rate. Of the 50 families we have only 3 have been lost to follow-up, reflecting a 97% retention rate.

Baseline characteristics of the enrolled children include: mean age 8.9 yrs; 47% males; 46% with one or more skin tests. Fifty-three of the caretakers smoke. Morbidity was high in the children, with 8% being hospitalized and 40% having to go to the Emergency Room for asthma in the last 3 months. Fifty-six reported wheezing in the last 2 weeks.

Investigators were able to complete second borne visits for 93% of participants at 6 and 12 months. Although we were not able to analyze separately results from those who had been randomized to the treatment group, we were impressed with the consistency of these outcomes. For example median cockroach allergen Bla g 1 in the kitchen was 35 and 31 U/gm at 6 and 12 months compared to 32.5 U/gm at baseline. Similarly PM10 was 32.4 µg/m³ and 38.6 µg/m³ at 6 and 12 months.

Future Activities:

During year 05, investigators will continue to conduct the intervention on newly recruited families. They will continue follow-up telephone calls at 3, 6, 9 and 12 months and home evaluations at 6 and 12 months. Data cleaning will continue and the treatment outcome can be evaluated toward the end of the year. As the need for study staff decreases we will discharge some staff (study recruiters) and will cross train the home educators to conduct follow-up evaluations. In addition, they have been asked by the community Advisory Board to increase community outreach efforts by making preliminary data available to community groups, to the schools and to the health department. They have expressed interest in the field staff contributing to training of existing community health programs that are conducted through churches. As their field staff, both the educators and the nurse, Ms. Jennette Logan, who serves as the coordinator of the intervention program, will be able to devote more time to these activities.

Supplemental Keywords:

Allergens, Asthma, Biochemistry, Children's Health, Disease and Cumulative Effects, Ecological Risk Assessment, Epidemiology, Human Health Risk Assessment, age-related differences, airway disease, community-based intervention, asthma morbidity., RFA, Health, Air, Scientific Discipline, Susceptibility/Sensitive Population/Genetic Susceptibility, Health Risk Assessment, Risk Assessments, particulate matter, Biology, genetic susceptability, Environmental Chemistry, Allergens/Asthma, Children's Health, indoor air, indoor air quality, childhood respiratory disease, epidemeology, health effects, Human Health Risk Assessment, asthma morbidity, air quality, environmental hazard exposures, sensitive populations, allergen, asthma, indoor environment, biological response, antigen, human exposure, household, morbidity, children, exposure, PM, allergic response, ambient air, intervention, airborne pollutants, home, assessment of exposure, air pollution, human health risk, airway disease

Progress and Final Reports:

Original Abstract

1998

1999

2000 Progress Report

Final

Main Center Abstract and Reports:

R826724    Center for the Study of Childhood Asthma in the Urban Environment

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R826724C001 A Randomized, Controlled Trial of Home Exposure Control in Asthma
R826724C002 Mechanisms Of Particulate-Induced Allergic Asthma
R826724C003 Genetic Mechanisms of Susceptibility to Inhaled Pollutants
R826724C004 The Relationship Of Airborne Pollutants And Allergens To Asthma Morbidity