Abstract
Background:
Multicomponent interventions have been reported as effective strategies for improving allergen reduction and asthma control. However, few studies have evaluated the integration of an indoor air quality (IAQ) system and e-health as part of multicomponent interventions.
Objective:
To evaluate the effects of multicomponent interventions on house dust mite allergens, indoor particulate matter, and knowledge and trigger reduction behaviors (TRBs) of caregivers.
Methods:
Twelve pediatric asthmatic patients with dust mite sensitization were randomly assigned to either a multicomponent intervention group or a control group. In the multicomponent intervention group, IAQ systems were installed in participants’ bedrooms, bedding covers were provided, and asthma education was delivered through the LINE application, while the control group received conventional treatment. House dust mite allergen levels were analyzed using the enzyme-linked immunosorbent assay technique, and particulate matter <2.5 micrometer diameter (PM2.5) concentrations were measured at baseline, 4 weeks, and 8 weeks postenrollment. Questionnaires were used to evaluate TRBs and asthma knowledge among caregivers before and after the intervention.
Results:
There were decreased Dermatophagoides pteronyssinus allergen group 1 and Dermatophagoides farinae allergen group 1 levels in the multicomponent intervention group compared to the control group; however, the reduction was not statistically significant. Indoor PM2.5 concentrations were significantly lower in the multicomponent intervention group compared to the control group after 4 and 8 weeks (P = 0.005). Statistically significant improvement in overall TRBs (P = 0.04) and a trend in improving asthma knowledge among caregivers were observed in the multicomponent intervention group compared to the control group, although the difference did not reach statistical significance (P = 0.06).
Conclusion:
Implementation of an IAQ system and asthma education through the LINE application, as part of multicomponent interventions, resulted in a significant reduction in indoor PM2.5 concentrations and improved TRBs among caregivers.
Keywords: Asthma, e-health, house dust mite, indoor air quality system, multicomponent intervention, particulate matter
1. Introduction
Asthma is a chronic inflammatory respiratory disease that has a high impact on health, functioning, and quality of life [1]. The complex interplay between genetics and environment contributes to asthma development. Environmental exposures, including inhalant allergens, viral infections, and air pollution, have also been implicated as risk factors for asthma exacerbation [2, 3]. Previous studies have reported that house dust mites are the predominant aeroallergen sensitization among Thai pediatric asthmatic patients, accounting for 41% to 82% [4–6].
House dust mites are arthropods. They can survive by maintaining water balance from environmental humidity. If relative humidity (RH) falls below 50%, the reproduction and survival of house dust mites decreases [7]. Various measures have been recommended for house dust mite control, including the use of allergen-impermeable mattress covers, regular washing of bedding in hot water, removal of carpets, avoidance of soft toys and upholstered furniture, and humidity control [7, 8]. A recent pilot study in Thailand revealed that house dust mite allergen levels in the bedrooms of dust mite-sensitized patients with allergic rhinitis were significantly reduced after using a humidity control machine [9]. However, studies evaluating the effectiveness of humidity control in reducing house dust mites are still limited, and the results are inconsistent.
In addition to aeroallergens, air pollution contributes to asthma development and exacerbation. In children, immature immune and respiratory systems, along with more rapid respiratory rates and more outdoor activities, result in more likelihood of exposure to air pollutants [3]. According to a recent prospective study in Thai asthmatic children [10], exposure to high concentrations of fine particulate matter <2.5 micrometer diameter (PM2.5) led to asthma exacerbation within 3 days. Furthermore, a study comparing indoor and outdoor PM2.5 concentrations showed a correlation between ambient and indoor PM2.5 levels [11]. Therefore, indoor residents might still be at risk of exposure to high levels of PM2.5. Using air purifiers with high-efficiency particulate air (HEPA) filters may help reduce indoor PM2.5 concentration, resulting in better asthma control [12, 13].
Many studies have investigated the effectiveness of various interventions for allergen reduction, including acaricide, air-purification, carpet removal, HEPA vacuum, and mattress covers as single interventions or as part of multicomponent interventions. A previous systematic review showed that single interventions might be inadequate in controlling indoor allergens or alleviating asthma symptoms, while multicomponent interventions with different specific combinations of measures can improve various asthma outcomes. However, no combinations appeared to be optimally effective [14].
To achieve asthma control, many aspects, including asthma knowledge, compliance to medication use, and allergen avoidance, may be needed. Recently, there has been a trend in using electronic health (e-health) to provide health care among asthmatic patients. E-health interventions reported in previous studies include mobile health applications, short message services (SMS), and inhaler tracker devices. These tools have demonstrated efficacy in improving medication adherence and supporting asthma self-management [15, 16].
However, there are few studies evaluating the integration of an indoor air quality (IAQ) system and e-health as part of multicomponent interventions. Our study, Clean Air for Asthma and Allergy Program (CAAP), aimed to evaluate the effectiveness of these multicomponent interventions in reducing house dust mite allergen levels. We also studied the effects on PM2.5 concentrations, caregivers’ asthma knowledge, and trigger reduction behaviors (TRBs).
2. Materials and methods
2.1. Participants
Pediatric patients aged 1 to 15 years with physician-diagnosed asthma and house dust mite sensitization who had been hospitalized for asthma exacerbations within 12 months were enrolled in this study. House dust mite sensitization was defined by a positive skin prick test (mean wheal diameter of at least 3 mm) or elevated serum-specific IgE to Dermatophagoides pteronyssinus and/or Dermatophagoides farinae greater than 0.35 KUA/l. Exclusion criteria included patients with chronic lung diseases or active cardiovascular diseases, patients whose caregivers were unable to use smartphones, patients whose caregivers were illiterate or unable to understand Thai language, patients whose housing types or bedroom sizes were not suitable for IAQ system installation, or patients with plans to move out of the region within the next 3 months. Baseline characteristics and information about home environments were obtained from medical records and by using interviewer-administered questionnaires. Total nasal symptom score (TNSS) and childhood asthma control test (C-ACT) were obtained from patients and their caregivers by self-administered questionnaires at baseline, 4 weeks, and 8 weeks after interventions (Fig. 1).
Figure 1.
Flow diagram of interventions and data collections. The flow diagram has been designed using resources from Flaticon.com. C-ACT, childhood asthma control test; PM2.5, particulate matter <2.5 micrometer diameter; RH, relative humidity; TNSS, total nasal symptom score; TRB, trigger reduction behaviors.
2.2. Study design and setting
A randomized controlled trial involving a total of 12 pediatric patients was conducted. Block randomization was employed to allocate patients into either an 8-week multicomponent intervention group or a control group. The estimated sample size was determined based on results from a previous study [17]. At least 10 participants were needed to achieve a power of 90% at an alpha error of 0.05. Accounting for an assumed dropout rate of 10%, a total sample size of 12 subjects was required. The study protocol was conducted from December 2023 through February 2024 at Thammasat University Hospital, Pathum Thani, Thailand. This study period would not affect the outcomes related to house dust mite allergens, as the environmental dust mite burden remains consistent throughout the year in Thailand.
2.3. Interventions
Multicomponent interventions consisted of an IAQ system, allergen-impermeable mattress covers, and asthma education delivered via the smartphone LINE application. The IAQ system (UFT NEW NORMAL R32-12, Saijo Denki, Nonthaburi, Thailand) comprised an air-conditioner, a dehumidifier, and an air-purifier with HEPA filter (Fig. 2). These systems were installed in participants’ bedrooms. Caregivers were instructed to keep the system running continuously for 24 hours per day throughout the study period. To ensure effective humidity control, the rooms had to be kept closed at all times to minimize external air exchange. Caregivers were allowed to use air-conditioners as needed since the humidity control systems were not affected by temperature fluctuations. The systems were set to maintain a constant RH of 50% with real-time monitoring to ensure consistent control of humidity levels. Participants were instructed to stay in the bedrooms for at least 8 hours per day. Allergen-impermeable mattress covers were provided for participants. The LINE application, widely used for messaging in Thailand, served as the platform for delivering information about asthma to caregivers. The caregivers were asked to add our LINE official account to their friend lists. The information, including general asthma knowledge, asthma triggers, measures for house dust mite control, asthma medications, and asthma action plan, was delivered weekly in the form of messages and infographic content. The official account also offered written asthma action plans and videos demonstrating how to use inhalers. Participants in the control group received conventional treatments, including asthma medications and asthma education provided by pediatric allergists during visits to our asthma clinic.
Figure 2.
The IAQ system (UFT NEW NORMAL R32-12, Saijo Denki, Nonthaburi, Thailand) comprised an air-conditioner, a dehumidifier, and an air purifier with a HEPA filter. HEPA, high-efficiency particulate air; IAQ, indoor air quality.
2.4. Outcome measurements
The primary outcome was changes in indoor house dust mite allergen levels. The secondary outcomes included changes in indoor PM2.5 concentrations, caregivers’ TRBs, and caregivers’ asthma knowledge.
2.5. House dust mite allergen levels
Dust samples were collected from the surfaces of participants’ mattresses by using the same vacuum cleaner with an attached dust collector at baseline, 4 and 8 weeks after the interventions. Bedding covers were removed before sampling. The sampling time was 2 min/m2, and vacuuming was performed across the entire surface area [18]. The dust samples were stored in plastic bags at 4°C until analyzed. House dust mite allergen levels were analysed as Dermatophagoides pteronyssinus allergen group 1 (Der p 1) and Dermatophagoides farinae allergen group 1 (Der f 1) levels by using the commercial mite allergen enzyme-linked immunosorbent assay kits (InBio, USA) [19, 20] (performed by Bioscience Testing Laboratory, Nonthaburi, Thailand).
2.6. PM2.5 concentrations
Outdoor and indoor PM2.5 concentrations were measured by using a laser photometer with a PM2.5 sensor (DUST TRAK Model 8530; TSI Incorporated, MN, USA) at baseline, 4 and 8 weeks after the interventions. For indoor PM2.5 levels, the sensor was placed in the middle of participants’ bedrooms at 1 m above the floors.
2.7. Temperature and relative humidity
A temperature and humidity meter (FLUKE 971; WA, USA) with an accuracy of ± 0.5 °C for temperature and ± 2.5% for RH was used to measure both outdoor and indoor temperature and RH. Data were collected by placing the meter in the center of the bedrooms at baseline, 4, and 8 weeks after the interventions.
2.8. Trigger reduction behaviors and asthma knowledge
2.8.1. Trigger reduction behaviors
Information was obtained from caregivers using interviewer-administered questionnaires to assess the presence of asthma triggers within their home environments. The questionnaires contained 10 items related to house dust mite control measures and other asthma trigger management. Caregivers were asked to respond “yes” or “no” regarding certain TRBs. The TRB summary score ranged from 0 to 10, with a higher score indicating better behaviors in reducing indoor asthma triggers.
2.8.2. Asthma knowledge
Caregivers were evaluated to assess their understanding of asthma by using pre- and post-tests. The tests consisted of 25 true or false questions divided into 5 domains, including general asthma knowledge, asthma triggers and management, house dust mites and measures to control them, asthma treatment, and asthma action plan. The total score ranged from 0 to 25, with a higher score indicating better asthma knowledge.
The evaluations of both TRBs and asthma knowledge were conducted before and after an 8-week intervention. The asthma knowledge questionnaires were adapted from previously published studies [21, 22]. The questionnaires are provided in the Supplementary Appendix, http://links.lww.com/PA9/A51.
2.9. Statistical analysis
Descriptive data are presented as mean ± SD, median (IQR), or frequency. Fisher’s exact tests were used to compare categorical data between the 2 groups. Wilcoxon signed-rank tests were employed to compare continuous data before and after interventions, while Wilcoxon rank-sum tests were used to compare continuous data between groups. Repeated measure analysis of variance (ANOVA) and Friedman test were used to compare data at different time points. Data analysis was performed using SPSS version 28.0 (IBM Corp., Armonk, NY, USA) and STATA version 14.0 (StataCorp, College Station, TX, USA). P-value <0.05 was considered statistically significant.
2.10. Ethical consideration
This study was approved by the Human Research Ethics Committee of Thammasat University, Pathum Thani, Thailand (Approval number: 091/2023, Chairman Assoc. Prof. Waipoj Chanvimalueng, M.D.) on March 27, 2023. It was conducted in accordance with international guidelines including the Declaration of Helsinki, the Belmont Report, CIOMS Guidelines, and the International Conference on Harmonization-Good Clinical Practice (ICH-GCP). Assent and written informed consent were obtained from participants and their parents or legal guardians.
3. Results
A total of 83 patients were screened for eligibility for the study. In total 26 patients refused to enroll, 29 patients met exclusion criteria, and 16 patients were unable to be contacted. Therefore, 12 participants were enrolled in this study and were randomly assigned to either the multicomponent intervention group or the control group (Fig. 3). Baseline characteristics and demographic data are shown in Table 1. Eight subjects were male, with a median (IQR) age of 6.7 years (4.5, 10). All subjects had allergic rhinitis as a comorbidity. The subjects were similar between the 2 groups. There were more sources of air pollutants in the multicomponent intervention group and more smokers in the control group; however, no statistical difference in the home environment was observed.
Figure 3.
Flow diagram of participant recruitment and group assignment.
Table 1.
Baseline characteristics, demographic data, and home environment of participants by intervention groups
| Variables | Multicomponent intervention group (n = 6) | Control group (n = 6) |
|---|---|---|
| Age (months), median (IQR) | 66.5 (55, 104) | 107.5 (52, 125) |
| Male sex, n (%) | 4 (66.7%) | 4 (66.7%) |
| Atopic comorbidities, n (%) | ||
| Allergic rhinitis | 6 (100%) | 6 (100%) |
| Atopic dermatitis | 0 | 1 (16.7%) |
| Food allergy | 0 | 0 |
| Sensitisation, median (IQR) | ||
| MWD D.pteronyssinus (mm) | 6.25 (4, 8) | 8 (5, 11) |
| MWD D.farinae (mm) | 6.25 (3, 8.5) | 5 (4, 8) |
| Polysensitization, n (%) | 1 (16.7%) | 4 (66.7%) |
| Disease control, median (IQR) | ||
| C-ACT | 25 (23, 26) | 23 (20, 26) |
| TNSS | 1 (1, 4) | 3 (1, 5) |
| Family history, n (%) Family history of atopy |
3 (50%) | 4 (66.7%) |
| Socioeconomic status | ||
| Household income, baht/month, n (%) | ||
| <30,000 | 3 (50%) | 2 (33.3%) |
| 30,000–59,999 | 1 (16.7%) | 2 (33.3%) |
| ≥60,000 | 2 (33.3%) | 2 (33.3%) |
| Caregiver’s education, n (%) | ||
| Primary school | 1 (20%) | 1 (20%) |
| High school | 0 | 0 |
| College | 5 (83.3%) | 5 (83.3%) |
| Home environment, n (%) | ||
| Pets at home | 3 (50%) | 2 (33.3%) |
| Presence of mold | 2 (33.3%) | 2 (33.3%) |
| Second-hand smoke | 2 (33.3%) | 3 (50%) |
| Nearby factory or construction site | 3 (50%) | 1 (16.7%) |
| Close to street (<100 m) | 2 (33.3%) | 1 (16.7%) |
| Combustion pollutants | 2 (33.3%) | 1 (16.7%) |
Variables were compared by Fisher’s exact test and Wilcoxon Rank-sum test, all P values >0.05.
C-ACT, childhood asthma control test; MWD, mean wheal diameter; TNSS, total nasal symptom score.
3.1. House dust mite allergen levels
The levels of group 1 allergens were comparable at baseline. Following the 8-week intervention, there were decreased Der p 1 and Der f 1 levels in the multicomponent intervention group compared to the control group. However, the reduction in both allergens was not statistically significant (Fig. 4).
Figure 4.
Comparison of house dust mite allergen levels, Der p 1 and Der f 1 between multicomponent intervention group and control group. Data are presented as median (IQR). Friedman tests were used to compare house dust mite allergen levels at different time points. ns, not significant. Der f 1, Dermatophagoides farinae allergen group 1; Der p 1, Dermatophagoides pteronyssinus allergen group 1.
3.2. Relative humidity
The average indoor RH levels were similar at baseline (64.3 ± 1.2% in the multicomponent intervention group vs 64.7 ± 5.5% in the control group). A significant reduction in indoor RH was observed in the multicomponent intervention group compared to the control group (P = 0.002, Supplementary Table, http://links.lww.com/PA9/A52), with indoor RH in the multicomponent intervention group remaining constant within the range of 45% to 55% throughout the study period. Outdoor RH levels at each time point were similar in both groups (data not shown).
3.3. PM2.5 concentration
At baseline, the mean indoor PM2.5 concentration in the control group was higher than in the multicomponent intervention group. During the study period, there was a significant decrease in the average indoor PM2.5 concentrations at 4 weeks and 8 weeks after the intervention compared to baseline in both multicomponent interventions (P = 0.02) and control groups (P < 0.001). However, the decrease was significantly different between the groups (P = 0.005). At the end of the study, the mean indoor PM2.5 concentrations were 7.17 ± 2.79 μg/m3 in the multicomponent intervention group and 28.33 ± 4.63 μg/m3 in the control group (Fig. 5).
Figure 5.
Comparison of indoor PM2.5 concentrations between multicomponent intervention group and control group. Data are shown in mean ± SD. Two-way repeated measures ANOVA were used to compare PM2.5 concentrations at different time points between groups. *P < 0.05, **P < 0.01, ***P < 0.001. PM2.5, particulate matter <2.5 micrometer diameter. ANOVA, analysis of variance.
3.4. Trigger reduction behaviors
The total TRBs summary score significantly improved in the multicomponent intervention group while remaining unchanged in the control group (P = 0.04). The frequency of participants using allergen-impermeable mattress covers had reached 100% after interventions in the multicomponent intervention group. Increased proportions of families regularly washing bedding in hot water were observed in both groups. More families removed furry toys in the multicomponent intervention group, but not in the control group. Improvement in indoor pollutant controls, including enhanced indoor cooking ventilation and implementation of no-smoking measures, was observed only in the multicomponent intervention group. There were no changes in the frequency of vacuuming or in keeping pets outside the houses in both groups (Table 2).
Table 2.
Trigger reduction behaviors of caregivers: baseline and after 8-week interventions
| Trigger reduction behaviors (TRBs), n (%) | Intervention group (n = 6) |
Control group (n = 6) |
||
|---|---|---|---|---|
| Week 0 | Week 8 | Week 0 | Week 8 | |
| Vacuum patient’s bedroom at least once a week | 4 (66.7%) | 4 (66.7%) | 3 (50%) | 3 (50%) |
| Encase mattresses and pillows with impermeable covers | 3 (50%) | 6 (100%)* | 1 (16.7%) | 1 (16.7%) |
| Wash sheets and blankets in hot water at least once a week | 3 (50%) | 4 (66.7%) | 1 (16.7%) | 3 (50%) |
| Remove furry toys from the bedroom | 3 (50%) | 4 (66.7%) | 5 (83.3%) | 4 (66.7%) |
| Remove carpets from the bedroom | 5 (83.3%) | 5 (83.3%) | 6 (100%) | 6 (100%) |
| Keep pets outside the house or not own pets | 6 (100%) | 6 (100%) | 5 (83.3%) | 5 (83.3%) |
| Clean moldy areas, repair leaks | 5 (83.3%) | 5 (83.3%) | 5 (83.3%) | 4 (66.7%) |
| Remove visible mold | 5 (83.3%) | 6 (100%) | 6 (100%) | 4 (66.7%) |
| Use extractor hood for indoor cooking | 4 (66.7%) | 5 (83.3%) | 3 (50%) | 3 (50%) |
| Implement no-smoking measures | 4 (66.7%) | 5 (83.3%) | 6 (100%) | 6 (100%) |
| TRBs summary score, median (IQR) | 7 (6, 8) | 8 (7, 10)† | 6.5 (6, 7) | 6.5 (4, 9) |
All values are shown in number (percentage) except TRBs summary score (maximum score = 10).
Variables were compared by Fisher’s exact tests. P-value < 0.05.
Wilcoxon Signed-rank test was used to compare TRBs summary score before and after intervention. P value <0.05.
3.5. Asthma knowledge
The total pre-test scores of caregivers’ asthma knowledge were similar in both groups. After the intervention, the median total post-test scores increased in the multicomponent intervention group but did not reach statistical significance (P = 0.06), while the median post-test scores in the control group remained unchanged (P = 0.33). By examining each domain of asthma knowledge evaluated in our study, no differences were observed between pre- and post-test scores in both groups (Table 3).
Table 3.
Caregivers’ asthma knowledge: baseline and after 8-week interventions
| Domain | Intervention group (n = 6) | P value | Control group (n = 6) | P value | ||
|---|---|---|---|---|---|---|
| Pre | Post | Pre | Post | |||
| 1. General asthma knowledge | 4 (4, 5) | 4 (4, 5) | 0.66 | 4 (3, 4) | 3.5 (2, 4) | 0.41 |
| 2. Asthma triggers | 4.5 (4, 5) | 4.5 (4, 5) | 0.56 | 4 (4, 4) | 4 (4, 5) | 0.56 |
| 3. House dust mite control | 5 (4, 5) | 5 (5, 5) | 0.18 | 4.5 (4, 5) | 4.5 (4, 5) | 0.56 |
| 4. Treatment and medications | 3 (3, 3) | 4 (3, 4) | 0.71 | 3 (1, 3) | 3 (2, 4) | 0.18 |
| 5. Asthma action plan | 3 (3, 3) | 4 (3, 4) | 0.66 | 3 (1, 3) | 3 (2, 4) | 0.56 |
| Total score | 19 (17, 20) | 20.5 (19, 21) | 0.06 | 19.5 (19, 20) | 19.5 (16, 21) | 0.33 |
All data are shown in median (IQR), maximum score for each domain is 5, maximum total score is 25.
Wilcoxon signed-rank tests were used to compare pre- and post-test in each intervention group.
3.6. Total Nasal Symptom Score and childhood asthma control test
TNSS between the 2 groups was not significantly different at baseline. In the multicomponent intervention group, TNSS decreased at 4 weeks and remained low at 8 weeks. In contrast, TNSS in the control group also decreased at 4 weeks but rebounded to higher scores at 8 weeks. However, the difference between the 2 groups did not reach statistical significance (P = 0.08, Supplementary Figure 1, http://links.lww.com/PA9/A53).
C-ACT scores were comparable at baseline. In the multicomponent intervention group, C-ACT scores tended to increase over time, with improvements observed at 4 and 8 weeks postintervention. Meanwhile, C-ACT scores in the control group increased at 4 weeks but declined by 8 weeks. However, the differences in C-ACT score changes between the 2 groups were not statistically significant (P = 0.32, Supplementary Figure 2, http://links.lww.com/PA9/A54).
4. Discussion
Multicomponent interventions have been proposed as effective measures to improve asthma symptoms and enhance allergen reduction. However, there remains a lack of high-quality studies to provide recommendations of specific interventions for allergen control in asthmatic patients. According to the data from previous studies in Thailand [4–6], house dust mites remain the most prevalent allergens among Thai asthmatic patients. It has been proposed that reducing Der p 1 level to less than 2 μg/g of dust could prevent the development of IgE sensitization, while prevention of acute asthma exacerbations in house dust mite-allergic patients might require Der p 1 level below 10 μg/g of dust [18]. In addition to allergen exposure, pollutants such as PM2.5 can contribute to asthma development and exacerbation [3]. Therefore, interventions aiming to decrease these triggers may offer some benefits in improving asthma outcomes.
Our study explored the effects of implementing IAQ systems and providing asthma education via the LINE application as part of multicomponent interventions to reduce indoor asthma triggers, including house dust mite allergens and PM2.5. We found that our interventions might provide some benefits in controlling Der p 1 and Der f 1 levels. These benefits might result from humidity control by the IAQ system, which theoretically retards mite growth and survival, and from other mite control measures encouraged by our program. Moreover, the rebounds in Der p 1 and Der f 1 levels observed in the control group during the study might support the effect of our multicomponent interventions in controlling house dust mite allergen levels.
The small effect observed in our study might be due to our small sample sizes and short study duration. Furthermore, more than half of the participants’ homes had baseline allergen levels lower than 2 μg per gram of dust, which was lower than anticipated based on previously published studies in which homes had higher house dust mite allergen levels, mostly 10 to 100 μg per gram of dust [17, 23]. Arlian et al [17] found that maintaining indoor RH levels below 51% could significantly reduce house dust mite allergen levels. However, that study included more than 70 homes with high initial mite levels and took 17 months to complete. In a previous pilot study in Thailand by Manuyakorn et al [9], maintaining RH at 55% resulted in a noticeable reduction of Der f 1 level at 2 months, with a significant reduction observed after 4 months [9]. In contrast, a randomized trial by Hyndman et al [24], found that neither dehumidification nor behavioral intervention had a significant effect on house dust mite allergen levels.
We took measures to ensure consistency in PM2.5 measurements across all participants’ homes to mitigate seasonal variations. However, baseline PM2.5 concentrations were higher in the control group, though not statistically significant. This discrepancy might be attributed to differences in regions and nearby environments where participants’ homes were located. We used a two-way repeated measure ANOVA to analyze whether the reductions in indoor PM2.5 concentrations were due to our interventions or seasonal variations. The results indicated that the decrease in PM2.5 levels was influenced not only by lower ambient PM2.5 levels due to different timing of measurements but also by our multicomponent interventions. Our findings were consistent with a pilot study conducted in Fresno [12], which reported that using air purifiers could reduce PM2.5 levels, improve asthma control, and significantly reduce nasal symptoms. Our study also found that participants in the multicomponent intervention group could maintain good asthma and nasal symptoms while the participants in the control group had worsening nasal symptoms at 8 weeks postintervention. This might be due to the combined effects of our multicomponent intervention and medications. However, we did not evaluate drug compliance, which might influence symptom control.
Our participants were recruited from a comprehensive asthma clinic which routinely provided asthma counselling for patients and their caregivers by allergists and well-trained nurses. This might have resulted in higher baseline TRB summary scores and asthma knowledge scores than expected. However, slight improvements of TRBs and asthma knowledge of caregivers in the multicomponent intervention group were observed after the interventions. Therefore, encouragement in TRBs, along with asthma education using e-health as an adjunct to conventional methods might provide some benefits by improving asthma knowledge and trigger avoidance.
Despite the potential benefits offered by our program, the implementation of an IAQ system may not be practical for all families with asthmatic patients. Installing the system requires the expertise of companies specializing in IAQ systems, which may limit accessibility. Additionally, the installation cost is approximately 1500 USD. Furthermore, to maximize its effectiveness in controlling house dust mites through humidity regulation, the system needs to operate continuously, which may result in additional electricity costs of around 50 USD per month. Therefore, this system may not be affordable for families with low incomes.
To our knowledge, this is the first study to demonstrate the effects of multicomponent interventions, including the implementation of an IAQ system that provided humidity and PM2.5 control, along with e-health for asthma education and motivating trigger avoidance. This combination might serve as a comprehensive approach to asthma management. Our study also focused on evaluating outcomes among pediatric patients with mite-allergic asthma, which was different from previous studies including pediatric patients with allergic rhinitis [9] or adult patients with nonspecific respiratory complaints [17, 23, 24]. However, our study has several limitations. First, despite being conducted as a randomized controlled trial, we included only 12 participants due to budget constraints and difficulties in system installation. Second, our program did not provide personalized approaches to manage each participant’s indoor triggers but offered combined methods that addressed common problems we found during counseling in our asthma clinic. Third, the study duration was only 2 months which might not be sufficient to demonstrate significant effects on the outcomes of interest.
In conclusion, our study demonstrated that the implementation of an IAQ system, along with impermeable mattress covers and asthma education using LINE application, as parts of multicomponent intervention, could significantly decrease indoor PM2.5 concentrations and improve TRBs among caregivers. There was a modest effect in improving caregivers’ asthma knowledge and a trend in decreasing house dust mite allergen levels. Further studies involving larger sample sizes, longer study durations, and more individualized approaches may be needed to overcome barriers in controlling indoor triggers among asthmatic patients.
Acknowledgments
The authors would like to thank Assist. Prof. Dr. Nat Malainual and his team for their assistance with dust sample collection and analysis. We also thank Saijo Denki International Co., Ltd. for their support in providing and installing the machines for the IAQ systems. We sincerely appreciate all the participants and their caregivers for their participation in our study.
Financial support
The study was partly supported by Faculty of Medicine, Thammasat University Research Fund, Contract No. 2-17/2566.
Conflicts of interest
The authors have no financial conflicts of interest.
Supplementary material
Supplementary materials can be found via 10.5415/apallergy.2022.12.e38
Supplementary Appendix, Supplementary Table, Supplementary Figure 1, and Supplementary Figure 2
Click here to view
References
- 1.Sritipsukho P, Satdhabudha A, Nanthapisal S. Effect of allergic rhinitis and asthma on the quality of life in young Thai adolescents. Asian Pac J Allergy Immunol. 2015;33:222-226. [DOI] [PubMed] [Google Scholar]
- 2.Holgate ST, Wenzel S, Postma DS, Weiss ST, Renz H, Sly PD. Asthma. Nat Rev Dis Primers. 2015;1:15025. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Sompornrattanaphan M, Thongngarm T, Ratanawatkul P, Wongsa C, Swigris JJ. The contribution of particulate matter to respiratory allergy. Asian Pac J Allergy Immunol. 2020;38:19-28. [DOI] [PubMed] [Google Scholar]
- 4.Sritipsukho P. Aeroallergen sensitivity among Thai children with allergic respiratory diseases: a hospital-based study. Asian Pac J Allergy Immunol. 2004;22:91-95. [PubMed] [Google Scholar]
- 5.Yuenyongviwat A, Koonrangsesomboon D, Sangsupawanich P. Recent 5-year trends of asthma severity and allergen sensitization among children in southern Thailand. Asian Pac J Allergy Immunol. 2013;31:242-246. [DOI] [PubMed] [Google Scholar]
- 6.Visitsunthorn N, Chaimongkol W, Visitsunthorn K, Pacharn P, Jirapongsananuruk O. Great flood and aeroallergen sensitization in children with asthma and/or allergic rhinitis. Asian Pac J Allergy Immunol. 2018;36:69-76. [DOI] [PubMed] [Google Scholar]
- 7.Portnoy J, Miller JD, Williams PB, Chew GL, Miller JD, Zaitoun F, Phipatanakul W, Kennedy K, Barnes C, Grimes C, Larenas-Linnemann D, Sublett J, Bernstein D, Blessing-Moore J, Khan D, Lang D, Nicklas R, Oppenheimer J, Randolph C, Schuller D, Spector S, Tilles SA, Wallace D; Joint Taskforce on Practice Parameters. Environmental assessment and exposure control of dust mites: a practice parameter. Ann Allergy Asthma Immunol. 2013;111:465-507. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Kalayci O, Miligkos M, Pozo Beltrán CF, El-Sayed ZA, Gómez RM, Hossny E, Le Souef P, Nieto A, Phipatanakul W, Pitrez PM, Xepapadaki P, Jiu-Yao W, Papadopoulos NG. The role of environmental allergen control in the management of asthma. World Allergy Organ J. 2022;15:100634. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Manuyakorn W, Padungpak S, Luecha O, Kamchaisatian W, Sasisakulporn C, Vilaiyuk S, Monyakul V, Benjaponpitak S. Assessing the efficacy of a novel temperature and humidity control machine to minimize house dust mite allergen exposure and clinical symptoms in allergic rhinitis children sensitized to dust mites: a pilot study. Asian Pac J Allergy Immunol. 2015;33:129-135. [DOI] [PubMed] [Google Scholar]
- 10.Chankaew K, Sinitkul R, Manuyakorn W, Roekworachai K, Kamalaporn H. Spatial estimation of PM2.5 exposure and its association with asthma exacerbation: a prospective study in Thai children. Ann Glob Health. 2022;88:15. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Sompornrattanaphan M, Thongngarm T, Tantilipikorn P, Kreetapirom P, Foo J. The contribution of outdoor fine particulate matter to indoor air quality in Bangkok metropolitan region, Thailand – are indoor dwellers safe? Siriraj Med J. 2018;70:265-271. [Google Scholar]
- 12.Park HK, Cheng KC, Tetteh AO, Hildemann LM, Nadeau KC. Effectiveness of air purifier on health outcomes and indoor particles in homes of children with allergic diseases in Fresno, California: a pilot study. J Asthma. 2017;54:341-346. [DOI] [PubMed] [Google Scholar]
- 13.Lee GH, Kim JH, Kim S, Lee S, Lim DH. Effects of indoor air purifiers on children with asthma. Yonsei Med J. 2020;61:310-316. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Leas BF, D’Anci KE, Apter AJ, Bryant-Stephens T, Lynch MP, Kaczmarek JL, Umscheid CA. Effectiveness of indoor allergen reduction in asthma management: a systematic review. J Allergy Clin Immunol. 2018;141:1854-1869. [DOI] [PubMed] [Google Scholar]
- 15.Poowuttikul P, Seth D. New concepts and technological resources in patient education and asthma self-management. Clin Rev Allergy Immunol. 2020;59:19-37. [DOI] [PubMed] [Google Scholar]
- 16.Mosnaim G, Safioti G, Brown R, DePietro M, Szefler SJ, Lang DM, Portnoy JM, Bukstein DA, Bacharier LB, Merchant RK. Digital health technology in asthma: a comprehensive scoping review. J Allergy Clin Immunol Pract. 2021;9:2377-2398. [DOI] [PubMed] [Google Scholar]
- 17.Arlian LG, Neal JS, Morgan MS, Vyszenski-Moher DL, Rapp CM, Alexander AK. Reducing relative humidity is a practical way to control dust mites and their allergens in homes in temperate climates. J Allergy Clin Immunol. 2001;107:99-104. [DOI] [PubMed] [Google Scholar]
- 18.Platts-Mills TA, de Weck AL, Aalberse RC, et al. Dust mite allergens and asthma--a worldwide problem. J Allergy Clin Immunol. 1989;83(2 Pt 1):416-427. [DOI] [PubMed] [Google Scholar]
- 19.Luczynska CM, Arruda LK, Platts-Mills TA, Miller JD, Lopez M, Chapman MD. A two-site monoclonal antibody ELISA for the quantification of the major Dermatophagoides spp. allergens, Der p I and Der f I. J Immunol Methods. 1989;118:227-235. [DOI] [PubMed] [Google Scholar]
- 20.Prester L, Brcić Karaconji I, Macan J. Determination of mite allergens in house dust using the enzyme immunoassay. Arh Hig Rada Toksikol. 2007;58:413-419. [DOI] [PubMed] [Google Scholar]
- 21.Ho J, Bender BG, Gavin LA, O’Connor SL, Wamboldt MZ, Wamboldt FS. Relations among asthma knowledge, treatment adherence, and outcome. J Allergy Clin Immunol. 2003;111:498-502. [DOI] [PubMed] [Google Scholar]
- 22.Franken MMA, Veenstra-van Schie MTM, Ahmad YI, Koopman HM, Versteegh FGA. The presentation of a short adapted questionnaire to measure asthma knowledge of parents. BMC Pediatr. 2018;18:14. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Cabrera P, Julià-Serdà G, Rodríguez de Castro F, Caminero J, Barber D, Carrillo T. Reduction of house dust mite allergens after dehumidifier use. J Allergy Clin Immunol. 1995;95:635-636. [DOI] [PubMed] [Google Scholar]
- 24.Hyndman SJ, Vickers LM, Htut T, Maunder JW, Peock A, Higenbottam TW. A randomized trial of dehumidification in the control of house dust mite. Clin Exp Allergy. 2000;30:1172-1180. [DOI] [PubMed] [Google Scholar]