There is strong evidence for the impact of home environmental interventions on asthma-related healthcare utilization, cost-effectiveness, and returns on investment. There is also sufficient evidence for their effectiveness in improving asthma-related health outcomes.
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The findings below synthesize the results of home environmental interventions for asthma across the following three domains of measurement:
There is growing consensus that access to safe and affordable housing is a key health determinant. Housing can impact health based on accessibility, affordability, stability, quality, safety, and surroundings.
Housing Stability
Affordable housing in the United States (U.S.) has become increasingly difficult to access. In 2023, 51.8% of all American renters spent at least 30% of their income on rent[1]. In 2020, one in five U.S. households reported challenges with being able to afford their rent or mortgage payment and, therefore, were identified as housing insecure[2]. Up to 3.6 million eviction cases were filed annually between 2000 and 2018 [3],[4]. Individuals are more likely to be evicted if they identify as Black or Hispanic/Latino, women, or low-income[5]. The housing affordability crisis is compounded by a steep rise in the cost of rent while the increase in renters’ earnings lag[6]. A U.S. Conference of Mayors survey found seven of 10 Americans are concerned about housing costs and its affordability[7].
In the past three years, the median monthly rental price has increased by 18% and the median purchase price for housing has increased by 21% leading to increased homelessness[8]. The U.S. Department of Housing and Urban Development (HUD) identifies “a person who lacks a fixed, regular and adequate nighttime residence” as experiencing homelessness[9]. According to the National Alliance to End Homelessness, a January 2023 count identified a record-high of 653,104 people experiencing homelessness (a 12.1% increase since 2022) across the U.S., with more than 50% of those individuals experiencing unsheltered homelessness. About 61% of people experiencing homelessness identify as men, while homelessness among those who identify as women is growing rapidly by over 20% between 2022 to 2023. Since 2015, transgender individuals have experienced a 217% increase in homelessness[10].
The two factors that pose the greatest risk for homelessness are being severely housing cost-burdened and living in “doubled-up” overcrowded homes, also known as ‘couch surfing.’ Additional risks include an individual that identifies as LGBTQ+, being a survivor of intimate partner violence, exiting the criminal justice system, being a youth aging out of foster care, as well as ongoing mental health and substance use disorders[11]. Individuals in these groups may face discrimination and safety issues that make accessing both housing and sustainable employment difficult.
Housing Quality and Impact on Health
The health effects of housing instability and homelessness include adverse physical and mental health outcomes, chronic disease, and injury. There is a significant association between eviction rates and any cause of mortality with the strongest association in counties with higher proportions of Black and women residents[12]. Black, American Indian/Alaska Native, and Hispanic/Latino communities disproportionately live in households that are rent-burdened and of low housing quality while experiencing some of the greatest health disparities[13].
Housing of poor quality can directly impact health via exposure to things like lead, mold, asbestos, or poor air quality[14]. Additionally, exposure to extreme indoor temperatures, overcrowding, or lack of proper fire safety requirements (e.g., smoke and carbon monoxide alarms) can be deleterious to health. Poor housing conditions have a disproportionately adverse impact on children, older adults, people with physical disabilities, and individuals of low socioeconomic status. Housing quality also includes neighborhood factors such as incidence of violence, environmental conditions, access to transportation, and availability of other social services and supports.
Asthma is a chronic condition that affects the airways by triggering inflammation and narrowing which inhibits the flow of air in and out of the lungs[15]. Asthma affects one in 13 people in the U.S. and is manageable through monitoring, trigger-avoidance, and medications. Children who identify as African American are 60% more likely to develop asthma than their non-Hispanic White counterparts[16]. Children living in strained socio-economic environments have an increased risk of developing asthma due to exposure to allergens in the home. Research has established that exposures to endotoxins and indoor allergens (e.g., dust, pests, pets’ hair and dander, and mold) frequently found in urban and under-resourced home environments are associated with the development of asthma in children. It is estimated that as much as 40% of the risk of asthma in non-White children is attributable to exposure to allergens found in the home, and that this increased risk can be reduced, if not eliminated[17].
Asthma mitigation interventions outlined in this assessment include single and multi-component; multi-trigger services, educational sessions, dust mitigation, mattress pillow protector application, cockroach mitigation, in-home-asthma follow-up, environmental control educational programs, in-home assessments, reduction in residential health and safety hazards, home-based education from a public health nurse or health educator, providing cleaning supplies, and possible home modifications, such as weatherization. A single-component intervention is an individual mitigation strategy targeted at a specific allergen to which an individual is both exposed and determined to have developed reactivity, or sensitivity to. Single-component allergen mitigation interventions may include pillow and mattress covers for dust mites, mold mitigation, pest removal (e.g., cockroaches or mice), and HEPA filter vacuums for pet dander. Identifying a person’s specific allergens may require skin or in vitro tests to determine an individual’s reactivity to specific allergens, accompanied by education to develop a personal avoidance strategy to address the allergens[18]. A multicomponent intervention is the simultaneous implementation of two or more of the aforementioned single component interventions at the same time as part of a bundled approach targeted at one or more allergens[19].
Funding can be difficult to attain as interventions may require a patchwork of different funding sources. For example, weatherization funds are provided through the U.S. Department of Energy and the U.S. Department of Health and Human Services Low-Income Home Energy Assistance Program[20]. Additionally, supplemental funding to address triggers can be obtained through HUD’s Lead Hazard Control Program for common health hazards. Thirteen states have at least some coverages for asthma home visits and interventions through Medicaid6. Medicaid-funded asthma interventions include in-home assessments, asthma management education, and low-level interventions[21]. There has been some exploration of covering intensive home remediation and cleaning services under Medicaid, particularly under 1115 wavers and through social impact bonds; however, these services are primarily paid for through other means[22]. For instance, private and locally controlled funding sources may be available through the city or state housing departments. Other potential funding sources include Community Development Block Grants, foundation grants, hospital community benefits dollars, community development grants and services through financial institutions, and local or state government financing for relevant purposes.
Children aged 3-12 with poorly controlled and persistent asthma in the most urban Baltimore metropolitan areas. Most children (75%) had moderate/severe persistent asthma. Over half (56%) had secondhand smoke (SHS) exposure and 83% tested positive for >1 allergen sensitization.
Intervention was a home-based asthma follow-up and environmental control (EC) educational program delivered by trained nurses and nurse practitioners to the child and caregiver. Enrollees received an ED medical follow-up visit within seven days of the initial ED visit resulting in enrollment, two home nurse visits for targeted EC education, and remediation based on the child's allergen sensitization results (e.g., positive mouse allergy: mouse traps; positive cockroach allergy: cockroach bait and delivered kitchen trash cans). For caregivers of children who smoke, motivational interviewing sessions were conducted to implement a total home smoking ban. Primary care asthma care was scheduled within four weeks.
Randomized controlled trial. 222 children with poorly controlled asthma were randomized into a home-based EC intervention enrollment or control group and followed for ED visits over 12 months. All children received allergen-specific Immunoglobulin E serologic testing and SHS exposure biomarker testing to inform the EC intervention. Pharmacy data was examined for asthma medication fills.
Healthcare Cost, Utilization & Value: There was no difference in increased risk of >1 ED visit at 12 months between intervention and control groups. Among children without secondhand smoke exposure, the median time to first recurrent ED visit differed by group (control: 195; intervention: >365 days) after adjusting for confounding variables.
Children enrolled in Medicaid and Children’s Medical Services who had inadequately controlled asthma. Of the 23 children, 14 were boys, 21 were African American, and 18 had an estimated annual household income of less than $30,000. For 15 of the enrollees, the head of household was described as the mother. Four households included smokers, and only one reported smoking inside the home.
A multi-component, multi-trigger intervention including four educational sessions and home asthma trigger reductions. The most common environmental interventions implemented were dust mitigation, mattress or pillow protector application, and cockroach mitigation.
Pragmatic quasi-experimental pretest-posttest study. 25 children were recruited for the study, 23 completed the program. Children’s caregivers reported outcomes at baseline, one to three months, six months, and 12 months.
Healthcare Cost, Utilization & Value: Caregivers report significantly fewer emergency department visits (1.7 vs 0.6, p=0.02).
Health: By study-end, the number of children with asthma that was assessed as well controlled increased to 17 out of 20 (p < 0.001).
Social: Caregivers reported significantly fewer days of missed school (6.4 vs 4.2, p=0.01).
Residents with asthma in 13 counties funded for program implementation in New York. Participants were referred either through canvassing door-to-door (C), referred by the community (R), or targeted as Medicaid enrollees with poorly controlled asthma (T). A greater proportion of participants in the T-group compared with the other groups were non-White (84% vs ∼50%, respectively) and Hispanic/Latino (30% vs ∼15%, respectively) and received public assistance (98% vs 60%-77%, respectively). Roughly half of the participants in each group were adults, and 60% to 70% were female.
The New York State Healthy Neighborhoods Program (HNP) provides in-home assessments and minor to moderate interventions (education, referrals, or lower-cost products) using lay staff to reduce residential health and safety hazards in selected communities. Three to six months after the initial visit, staff are expected to conduct revisits for roughly a quarter of all homes, prioritizing those with the most serious conditions and/or with residents with asthma. During the revisit, the conditions are reassessed, and any new or ongoing problems are addressed. The three cohorts included the following: canvassing (C), 752 residents in 457 dwellings; referrals from the community (R), 573 residents in 307 dwellings; targeted Medicaid enrollees with poorly controlled asthma (T), 140 residents in 140 dwellings.
Pre-post analysis. 1,465 residents with asthma in 904 dwellings completed both an initial visit and a revisit. Environmental conditions and asthma self-management strategies as well as morbidity and quick relief medication use were assessed.
Improvement was calculated for conditions initially present, and McNemar's test assessed significant changes in hazard presence (P < .05; SAS v9.4).
Three asthma outcomes were analyzed: days with worsening asthma/attacks and days missed by the child or family members due to asthma. Mean values were presented at each visit and the change (initial − revisit) with 95% CIs.
Healthcare Cost, Utilization & Value: HNP provides a favorable ROI, with an estimated benefit-to-program cost ratio of 2.03 and a net benefit of $311 per resident with asthma.
Health: In the T group, there was a modest but significant (11%) smoking reduction not seen in the other two groups. At revisit, the mean asthma triggers scores were significantly different (P < .001) for two pairs: T versus R and T versus C with T seeing the largest improvements. The mean scores decreased significantly in all three groups. Among participants who did not know or use strategies, the greatest significant improvements were reported for participants in the T group for knowing their personal triggers (100%), knowing how to avoid triggers (100%), and using the peak flow meter (85%). In this group, everyone not taking controller medication every day was taking it every day at the revisit.
Social: There was a significant reduction of 40% to 60% of cockroaches and mold in all groups. Rodents were reduced significantly in all three groups, (T = 100%, R= 61%, and C= 45%). Post-intervention, children in the T group had significantly lower means: 2.8 missed days with worsening asthma, 2 missed days of school or daycare, and 0.4 missed days of work by another family member. Adults in the T group reported a decrease from 7.1 to 4.3 missed days of work after the intervention. The mean number of missed days of school or work and missed days of work by another family member were negligible in all three groups.
Families with children with asthma residing in Columbus, Ohio, with a family income at or below 80% of median income ($54,900 for a family of four). Participating children ranged in age from seven months to 18 years. The majority were African American. Most survey respondents were mothers. Most caregivers (63.4%) were not employed outside of the home and had at least a high school education. At baseline, over half (57.4%) of participating children experienced symptoms of asthma for four or more days in the preceding two weeks; over a third (43.4%) had been to the emergency department because of asthma in the past three months.
The Columbus Public Health Department’s “Healthy Homes Program.” Participants received home-based education from a public health nurse or a health educator, cleaning and other supplies, and physical home interventions such as mold abatement and pest control.
Pre-post analysis. This study used parent self-reported quantitative and qualitative data which were collected through baseline and follow-up surveys. A total of 115 participants for whom baseline and follow-up data were available were included in the analysis.
Survey data was used to evaluate asthma outcomes, caregiver quality of life, trigger-related activities, and asthma management activities at baseline and six months following the intervention were evaluated using survey data.
Healthcare Cost, Utilization & Value: Emergency department visits over the prior three months decreased by a mean of 0.67 visits, a statistically significant level (p <0.01). Hospitalizations over the preceding three months declined, but the reduction was not statistically significant.
Health: All short-term measures (asthma symptom days, nighttime awakenings, days with activity limitation, and albuterol use) of asthma severity decreased significantly following the intervention. At baseline, participants had a mean of 2.5 symptom days per week. At follow-up, mean symptom days decreased to 1.3 days per week which falls into the “well controlled” range. Albuterol use for symptom control decreased from a mean of 2.3 days per week to a mean of 1.1 days per week.
Social: The number of missed school days and caregiver-missed workdays declined significantly. Participating children missed an average of 3.4 fewer school days and caregivers missed an average of 2.6 fewer workdays over a six-month period. Nighttime awakenings were reduced by a mean of 1.9 nights, days with activity limitation were reduced by a mean of 2.2 days, and days that albuterol was used decreased by a mean of 2.4 days. The number of caregivers who reported using fragrance-free cleaning products increased by 157%, and those who reported using their bathroom fan and open windows while showering increased by 43%. Caregivers were 10.5 times more likely to report using an allergen-impermeable encasing on their child's pillow, mattress, or box spring at follow-up.
Urban households with children with asthma earning low incomes in Lowell, Massachusetts. The population sample was predominantly Hispanic (52%), followed by Asian (15%), ‘Other’ (15%), White (14%), and Black (5%). While most children lived in smoke-free and pet-free homes, household pests were the most frequently reported allergy trigger (cockroaches 30% and rodents 29%).
Home health workers provided household safety education, asthma prevention education, and targeted environmental intervention to decrease asthma triggers and improve household safety (e.g. integrated pest management, commercial cleaning, providing healthy home cleaning equipment and supplies, and education). The cost of the in-home remediation was $192 per child, for a total of $32 ,640 for the 170 study participants.
Pre-post analysis. Environmental data and health information were collected with a questionnaire, as well as dust samples at baseline and at follow-up 11-12 months later. 116 households with 170 children (14 years and younger) were enrolled.
Healthcare Cost, Utilization & Value: The estimated medical savings over a four-week assessment period was $71,162. After deducting the $32,640 intervention cost from this amount, there was an estimated net savings of $38, 522 for the four-week period, $394 ,342 for six months, and $821, 304 for 12 months.
Health: Virtually every clinically relevant measure showed a statistically significant improvement, including episodes of wheezing, asthma attacks, ED visits, hospitalizations (eight in the previous four weeks at baseline down to 0 [0.1 (0.01, 0.8)]), physical activity and emotional health scores, asthma medication use, and sleep quality. At follow-up, 63 children used no medication, a drop from 85% at baseline to 59% of study participants (p < 0.001).
Families served by the Boston Children’s Hospital Community Asthma Initiative (CAI).
CAI provided home visits and case management services for families identified through ED visits and hospitalizations.
ROI analysis. Coarse cost-matching of participants (N=208) with randomly selected individuals with similar costs. Asthma costs for the two groups were extracted from the hospital database for ED visits and hospitalizations for one year before and 10 years of follow-up. The difference in cost-reduction between CAI and comparison patients was used to compute the adjusted return on investment (aROI).
Healthcare Cost, Utilization & Value: The cost reduction difference for CAI was significant at one year (P = 0.0001) and two years (P = 0.03) but did not reach the level of significance for years 3-10. The CAI group had a greater cumulative cost reduction of $5,321 (P = 0.08, not significant). The average program cost per patient was $2,636. CAI broke even after three years (aROI = 1.04) and yielded an aROI of 1.99 at 10 years.
Parents and other family members, childcare workers, and teachers involved in the care and education of infants and young children (from birth to 12 years of age).
Single component interventions to reduce secondhand smoke exposure in children. All mechanisms were eligible, including smoking prevention, cessation, and control programs. These include health promotion, social-behavioral therapies, technology, education, and clinical interventions.
Systematic review (Cochrane review). 78 controlled clinical trials (both randomized and non-randomized) were included.
Health: The review failed to show sufficient evidence to identify an approach that consistently demonstrated success in reducing children’s exposure to this asthma trigger; the quality of evidence ranged from low to very low.
Children diagnosed with asthma or who showed symptoms of asthma who participated in a community-based asthma program with multiple intervention components.
Community-based interventions with at least two components. Interventions included (A) asthma self-management education, (B) home environmental assessment (i.e., home visits for trigger assessments with or without remediation supplies), (C) care coordination (i.e., connecting patients/families with relevant health care or social services), (D) school involvement (e.g. asthma education for patients or school personnel, behavioral counseling at school, etc.), (E) involvement of primary healthcare providers for ongoing asthma assessment, provision of an asthma action plan, etc., (F) community involvement (e.g. awareness campaign, neighborhood support, etc.) or (G) advocacy for government/local organization involvement in policy changes.
Systematic review and meta-analysis. A total of 21 studies were included in the final analysis (19 pre-post interventions, one RCT, and one retrospective study).
Healthcare Cost, Utilization & Value: Asthma programs with multicomponent interventions were associated with a significant reduction in asthma-related ED visits (Odds Ratio [OR]=0.26; 95% Confidence Interval [CI], 0.20–0.35), hospitalizations (OR=0.24; 95% I 0.15–0.38), number of days (mean difference = −2.58; 95% CI, −3.00 to −2.17) and nights with asthma symptoms (mean difference=−2.14; 95% CI, −2.94 to −1.34), use of short-acting asthma medications/bronchodilators (OR=0.28; 95% CI, 0.16–0.51), and increased use of asthma action plans (OR=8.87; 95% CI, 3.85–20.45).
Families with children and adolescents having an asthma diagnosis.
In-home interventions to reduce asthma triggers and improve asthma outcomes, involving home visits by trained personnel who performed at least two components (mitigation for pets, mold, cockroaches, rodents, tobacco smoke, indoor pollutants [e.g., gas stoves], and dust mites) to reduce asthma triggers in the home.
Systematic review. In total, 23 studies met inclusion criteria: 20 pediatric-centered studies and three adult-centered studies.
Health: Overall, in children, the number of days with asthma symptoms was reduced by an average of 21 days per year; school days missed were reduced by an average of 12.3 days per year; and the number of asthma acute care visits was reduced by an average of 0.57 visits per year.
Households comprising adults or children with asthma.
Allergen reduction interventions.
Systematic review. In total 59 randomized and eight nonrandomized trials addressed eight interventions: dust mite pesticide, air purification, carpet removal, HEPA vacuums, mattress covers, mold removal, pest control, and pet removal. Single-component interventions were assessed in 37 studies, and 30 assessed multicomponent interventions.
Health: For most interventions and outcomes, the evidence base was inconclusive or showed no effect on validated asthma control measures or pulmonary physiology. Asthma exacerbations were diminished in multicomponent studies that included HEPA vacuums or pest control, and quality of life improved in studies of air purifiers as well as in multicomponent studies that included HEPA vacuums or pest control. Overall, the study authors found that single interventions were less likely to be associated with improvement in asthma measures; while multicomponent interventions improved a variety of asthma-related outcomes, no combination of specific interventions appeared more effective than others.
Children and adolescents with asthma.
Interventions included home visits by trained personnel to assess the level of and reduce adverse effects of indoor environmental pollutants and educate households with asthma clients to reduce exposure to asthma triggers.
Systematic review. A total of 1,551 studies were identified in the search period (1950 to 2008), and 13 studies were included in this review.
Healthcare Cost, Utilization & Value: Program costs per participant per year ranged from $231–$14,858 (in 2007 U.S.$). Benefit-cost ratios ranged from 5.3–14, implying that for every dollar spent on the intervention, the monetary value of the resulting benefits, such as averted medical costs or averted productivity losses, was $5.30–$14.00 (in 2007 U.S.$). The range in incremental cost-effectiveness ratios was $12–$57 (in 2007 U.S.$) per asthma symptom-free day, which means that these interventions achieved each additional symptom-free day for net costs varying from $12–$57.
