Impact of socioeconomic factors on allergic diseases.

Allergic and immunologic conditions, including asthma, food allergy, atopic dermatitis, and allergic rhinitis, are among the most common chronic conditions in children and adolescents that often last into adulthood. Although rare, inborn errors of immunity are life-altering and potentially fatal if unrecognized or untreated. Thus, allergic and immunologic conditions are both medical and public health issues that are profoundly affected by socioeconomic factors. Recently, studies have highlighted societal issues to evaluate factors at multiple levels that contribute to health inequities and the potential steps toward closing those gaps. Socioeconomic disparities can influence all aspects of care, including health care access and quality, diagnosis, management, education, and disease prevalence and outcomes. Ongoing research, engagement, and deliberate investment of resources by relevant stakeholders and advocacy approaches are needed to identify and address the impact of socioeconomics on health care disparities and outcomes among patients with allergic and immunologic diseases.

Associations between mitochondrial biomarkers, urban residential exposures and childhood asthma outcomes over 6 months.

Determining biomarkers of responses to environmental exposures and evaluating whether they predict respiratory outcomes may help optimize environmental and medical approaches to childhood asthma. Relative mitochondrial (mt) DNA abundance and other potential mitochondrial indicators of oxidative stress may provide a sensitive metric of the child's shifting molecular responses to its changing environment. We leveraged two urban childhood cohorts (Environmental Control as Add-on Therapy in Childhood Asthma (ECATCh); Columbia Center for Children's Environmental Health (CCCEH)) to ascertain whether biomarkers in buccal mtDNA associate with airway inflammation and altered lung function over 6 months of time and capture biologic responses to multiple external stressors such as indoor allergens and fine particulate matter (PM2.5). Relative mtDNA content was amplified by qPCR and methylation of transfer RNA phenylalanine/rRNA 12S (TF/RNR1), cytochrome c oxidase (CO1), and carboxypeptidase O (CPO) was measured by pyrosequencing. Data on residential exposures and respiratory outcomes were harmonized between the two cohorts. Repeated measures and multiple regression models were utilized to assess relationships between mitochondrial biomarkers, respiratory outcomes, and residential exposures (PM2.5, allergens), adjusted for potential confounders and time-varying asthma. We found across the 6 month visits, a 0.64 fold higher level of TF/RNR1 methylation was detected among those with asthma in comparison to those without asthma ((parameter estimate (PE) 0.64, standard error 0.28, p = 0.03). In prospective analyses, CPO methylation was associated with subsequent reduced forced vital capacity (FVC; PE -0.03, standard error 0.01, p = 0.02). Bedroom dust mouse allergen, but not indoor PM2.5, was associated with higher methylation of TF/RNR1 (PE 0.015, standard error 0.006, p = 0.01). Select mtDNA measures in buccal cells may indicate children's responses to toxic environmental exposures and associate selectively with asthma and lung function.

Indoor Environmental Exposures and Their Relationship to Allergic Diseases.

Cockroach, dust mite, cat, dog, mouse, and molds are major indoor allergens that have been associated with the development of allergic diseases and disease morbidity in allergen-sensitized individuals. Physical characteristics, such as allergen particle size, hydrophobicity, and charge, can determine an allergen's propensity to become airborne, location of respiratory tract penetration, and ability to elicit IgE responses in genetically predisposed individuals. Standardization and recent advancements in indoor allergen assessment serve to identify sources and distribution of allergens in a patient's home and public environment, inform public policy, and monitor the efficacy of allergen avoidance and therapeutics. Allergen exposure interventions have yielded mixed results with current US and international asthma guidelines differing on recommendations. A pragmatic, patient-centered approach to allergen avoidance includes: (1) tailoring intervention to the patient's sensitization and exposure status, (2) using a rigorous multifaceted intervention strategy to reduce allergen exposure as much as possible, and (3) beginning the intervention as soon as the patient is diagnosed. Further research into the risks/benefits of early allergen exposure, rapid and affordable in-home allergen assessment, and best practices for environmental control measures for asthma is needed.

Association of a Housing Mobility Program With Childhood Asthma Symptoms and Exacerbations.

Importance: Structural racism has been implicated in the disproportionally high asthma morbidity experienced by children living in disadvantaged, urban neighborhoods. Current approaches designed to reduce asthma triggers have modest impact. Objective: To examine whether participation in a housing mobility program that provided housing vouchers and assistance moving to low-poverty neighborhoods was associated with reduced asthma morbidity among children and to explore potential mediating factors. Design, Setting, and Participants: Cohort study of 123 children aged 5 to 17 years with persistent asthma whose families participated in the Baltimore Regional Housing Partnership housing mobility program from 2016 to 2020. Children were matched to 115 children enrolled in the Urban Environment and Childhood Asthma (URECA) birth cohort using propensity scores. Exposure: Moving to a low-poverty neighborhood. Main Outcomes: Caregiver-reported asthma exacerbations and symptoms. Results: Among 123 children enrolled in the program, median age was 8.4 years, 58 (47.2%) were female, and 120 (97.6%) were Black. Prior to moving, 89 of 110 children (81%) lived in a high-poverty census tract (>20% of families below the poverty line); after moving, only 1 of 106 children with after-move data (0.9%) lived in a high-poverty tract. Among this cohort, 15.1% (SD, 35.8) had at least 1 exacerbation per 3-month period prior to moving vs 8.5% (SD, 28.0) after moving, an adjusted difference of -6.8 percentage points (95% CI, -11.9% to -1.7%; P = .009). Maximum symptom days in the past 2 weeks were 5.1 (SD, 5.0) before moving and 2.7 (SD, 3.8) after moving, an adjusted difference of -2.37 days (95% CI, -3.14 to -1.59; P < .001). Results remained significant in propensity score-matched analyses with URECA data. Measures of stress, including social cohesion, neighborhood safety, and urban stress, all improved with moving and were estimated to mediate between 29% and 35% of the association between moving and asthma exacerbations. Conclusions and Relevance: Children with asthma whose families participated in a program that helped them move into low-poverty neighborhoods experienced significant improvements in asthma symptom days and exacerbations. This study adds to the limited evidence suggesting that programs to counter housing discrimination can reduce childhood asthma morbidity.

Intergenerational transmission of the effects of maternal exposure to childhood maltreatment in the USA: a retrospective cohort study.

BACKGROUND: Childhood maltreatment is associated with adverse health outcomes and this risk can be transmitted to the next generation. We aimed to investigate the association between exposure to maternal childhood maltreatment and common childhood physical and mental health problems, neurodevelopmental disorders, and related comorbidity patterns in offspring. METHODS: We conducted a retrospective cohort study using data from the Environmental influences on Child Health Outcomes (ECHO) Program, which was launched to investigate the influence of early life exposures on child health and development in 69 cohorts across the USA. Eligible mother-child dyads were those with available data on maternal childhood maltreatment exposure and at least one child health outcome measure (autism spectrum disorder, attention-deficit hyperactivity disorder [ADHD], internalising problems, obesity, allergy, and asthma diagnoses). Maternal history of childhood maltreatment was obtained retrospectively from the Adverse Childhood Experiences or Life Stressor Checklist questionnaires. We derived the prevalence of the specified child health outcome measures in offspring across childhood and adolescence by harmonising caregiver reports and other relevant sources (such as medical records) across cohorts. Child internalising symptoms were assessed using the Child Behavior Checklist. Associations between maternal childhood maltreatment and childhood health outcomes were measured using a series of mixed-effects logistic regression models. Covariates included child sex (male or female), race, and ethnicity; maternal and paternal age; maternal education; combined annual household income; maternal diagnosis of depression, asthma, ADHD, allergy, or autism spectrum disorder; and maternal obesity. Two latent class analyses were conducted: to characterise patterns of comorbidity of child health outcomes; and to characterise patterns of co-occurrence of childhood maltreatment subtypes. We then investigated the association between latent class membership and maternal childhood maltreatment and child health outcomes, respectively. FINDINGS: Our sample included 4337 mother-child dyads from 21 longitudinal cohorts (with data collection initiated between 1999 and 2016). Of 3954 mothers in the study, 1742 (44%) had experienced exposure to abuse or neglect during their childhood. After adjustment for confounding, mothers who experienced childhood maltreatment were more likely to have children with internalising problems in the clinical range (odds ratio [OR] 2·70 [95% CI 1·95-3·72], p<0·0001), autism spectrum disorder (1·70 [1·13-2·55], p=0·01), ADHD (2·09 [1·63-2·67], p<0·0001), and asthma (1·54 [1·34-1·77], p<0·0001). In female offspring, maternal childhood maltreatment was associated with a higher prevalence of obesity (1·69 [1·17-2·44], p=0·005). Children of mothers exposed to childhood maltreatment were more likely to exhibit a diagnostic pattern characterised by higher risk for multimorbidity. Exposure to multiple forms of maltreatment across all subtypes of maternal childhood maltreatment was associated with the highest risk increases for most offspring health outcomes, suggesting a dose-response relationship. INTERPRETATION: Our findings suggest that maternal childhood maltreatment experiences can be a risk factor for disease susceptibility in offspring across a variety of outcomes and emphasise the need for policies focusing on breaking the intergenerational transmission of adversity. FUNDING: Environmental influences on Child Health Outcomes Program, Office of the Director, National Institutes of Health.

Comprehensive home environmental intervention did not reduce allergen concentrations or controller medication requirements among children in Baltimore.

OBJECTIVE: To determine if the addition of home environmental control strategies (ECSs) to controller medication titration reduces asthma controller medication requirements and in-home allergen concentrations among children with persistent asthma in Baltimore City. METHODS: 155 children ages 5-17 with allergen-sensitized asthma were enrolled in a 6-month randomized clinical trial of multifaceted, individually-tailored ECS plus asthma controller medication titration compared to controller medication titration alone. Participants had to meet criteria for persistent asthma and have had an exacerbation in the previous 18 months. Allergen sensitization (mouse, cockroach, cat, dog, dust mite) was assessed at baseline and home dust allergen concentrations were measured at baseline, 3 and 6 months. ECS was delivered 3-4 times over the trial. Asthma controller medication was titrated using a guidelines-based algorithm at baseline, 2, 4, and 6 months. The primary outcome was controller medication treatment step at 6 months (0-6, as-needed albuterol to high-dose ICS + LABA). RESULTS: The population was predominately Black (90%), on public insurance (93%), and male (61%). The mean age was 10.1 years (SD 3.3). More than 70% were sensitized to a rodent, >50% to cockroach, and 70% were polysensitized. At 6 months, there were no differences in either treatment step (3.8 [SD 1.4] vs. 3.7 [SD 1.5]) or allergen concentrations between groups. CONCLUSION: Among this predominantly low-income, Black pediatric asthma population, the addition of ECS to controller medication titration reduced neither indoor allergen concentrations nor controller medication requirements compared to controller medication titration alone.

Indoor environmental exposures and obstructive lung disease phenotypes among children with asthma living in poor urban neighborhoods.

BACKGROUND: Air trapping is an obstructive phenotype that has been associated with more severe and unstable asthma in children. Air trapping has been defined using pre- and postbronchodilator spirometry. The causes of air trapping are not completely understood. It is possible that environmental exposures could be implicated in air trapping in children with asthma. OBJECTIVE: We investigated the association between indoor exposures and air trapping in urban children with asthma. METHODS: Children with asthma aged 5 to 17 years living in Baltimore and enrolled onto the Environmental Control as Add-on Therapy for Childhood Asthma study were evaluated for air trapping using spirometry. Aeroallergen sensitization was assessed at baseline, and spirometry was performed at 0, 3, and 6 months. Air trapping was defined as an FVC z score of less than -1.64 or a change in FVC with bronchodilation of ≥10% predicted. Logistic normal random effects models were used to evaluate associations of air trapping and indoor exposures. RESULTS: Airborne and bedroom floor mouse allergen concentrations were associated with air trapping but not airflow limitation (odds ratio 1.19, 95% confidence interval 1.02-1.37, P = .02 per 2-fold increase in airborne mouse allergen; odds ratio 1.23, 95% confidence interval 1.07-1.41, P = .003 per 2-fold increase in bedroom floor mouse allergen). Other indoor exposures (cockroach, cat, dog, dust mite, particulate matter, and nicotine) were not associated with air trapping or airflow limitation. CONCLUSION: Mouse allergen exposure, but not other indoor exposure, was associated with air trapping in urban children with asthma.

The influence of urban exposures and residence on childhood asthma.

Children with asthma who live in urban neighborhoods experience a disproportionately high asthma burden, with increased incident asthma and increased asthma symptoms, exacerbations, and acute visits and hospitalizations for asthma. There are multiple urban exposures that contribute to pediatric asthma morbidity, including exposure to pest allergens, mold, endotoxin, and indoor and outdoor air pollution. Children living in urban neighborhoods also experience inequities in social determinants of health, such as increased poverty, substandard housing quality, increased rates of obesity, and increased chronic stress. These disparities then in turn can increase the risk of urban exposures and compound asthma morbidity as poor housing repair is a risk factor for pest infestation and mold exposure and poverty is a risk factor for exposure to air pollution. Environmental interventions to reduce in-home allergen concentrations have yielded inconsistent results. Population-level interventions including smoking bans in public places and legislation to decrease traffic-related air pollution have been successful at reducing asthma morbidity and improving lung function growth. Given the interface and synergy between urban exposures and social determinants of health, it is likely population and community-level changes will be needed to decrease the excess asthma burden in children living in urban neighborhoods.

Asthma and the social determinants of health.

OBJECTIVE: To synthesize the growing body of literature on the role of social determinants of health (SDoH) in asthma and asthma disparities. DATA SOURCES: A pubmed.gov search was performed to identify published literature on SDoH, asthma, asthma disparities, and race and ethnicity. Current asthma statistics of the Centers for Disease Control and Prevention were reviewed. STUDY SELECTIONS: Relevant articles on SDoH, asthma, asthma disparities, and race and ethnicity were reviewed in detail. RESULTS: Black and Latinx Americans have a higher asthma prevalence and greater asthma morbidity than White Americans and also bear a disproportionate burden of SDoH. Inequities in SDoH are rooted in structural racism and population-level injustices that affect the socioeconomic status, physical environment, and health care access/quality of Black and Latinx Americans. There is evidence that racial/ethnic inequities in SDoH, such as socioeconomic status, neighborhood environment, housing, environmental exposures, and health care access/quality, contribute to excess burden of asthma prevalence/incidence, morbidity, exacerbations, and abnormal lung function among certain racial/ethnic populations. In addition, Black and Latinx communities experience high levels of long-term stress, which may increase asthma risk through direct effects on the immune system and hypothalamic-pituitary-adrenocortical activation. Long-term stress may also mediate the effects of SDoH on asthma. CONCLUSION: Although there is clear evidence linking SDoH to excess asthma risk and implicating SDoH in asthma disparities, the extent to which asthma disparities are explained by inequities in SDoH and the relative contributions of each of these SDoH to asthma disparities remain unclear. This knowledge is needed to effectively develop and test systems-level interventions targeting SDoH, with the ultimate goal of meaningfully reducing racial/ethnic asthma disparities.

Pediatric pulmonary hypertension: insulin-like growth factor-binding protein 2 is a novel marker associated with disease severity and survival.

BACKGROUND: Insulin-like growth factors (IGFs), and their binding proteins (IGFBPs), play a significant role in cardiovascular function and may influence the pathobiology of PAH. We determined the diagnostic and prognostic value of IGF1 and IGFBP2 in pediatric PAH. METHODS: Serum was analyzed by ELISA for IGF1 and IGFBP2 in pediatric PAH subjects from the NHLBI PAH Biobank (PAHB, n = 175) and a cohort of asthmatic subjects (n = 46, age 0-21 years) as a chronic pediatric pulmonary disease control. Biomarkers were analyzed with demographic and clinical variables for PAH severity. RESULTS: Serum IGF1 was significantly lower in PAH compared to controls, while IGFBP2 was elevated in PAH subjects compared to controls. In the PAHB, IGF1 was negatively associated with mPAP and PVR, while IGFBP2 was positively associated with PVR and negatively associated with cardiac output and 6-min walk distance. Higher IGFBP2 levels were associated with use of prostacyclin therapy. IGFBP2 was associated with death, transplant, or palliative shunt with a Cox proportional hazard ratio of 8.8 (p < 0.001) but not IGF1 (p = 0.13). CONCLUSIONS: Circulating IGFBP2 is a novel marker for pediatric PAH, which is associated with worse functional status, and survival. IGF axis dysregulation may be an important mechanistic target in pediatric pulmonary arterial hypertension. IMPACT: Pediatric pulmonary hypertension is a severe disease, with poorly understood pathobiology. There are few studies looking at the pathobiology of pulmonary hypertension only in children. The IGF axis is dysregulated in pediatric pulmonary arterial hypertension. IGF axis dysregulation, with increased IGFBP2, is associated with worse clinical outcomes in pediatric pulmonary artery hypertension. IGF axis dysregulation gives new insight into the disease process and may be a mechanistic or therapeutic target.

Childhood Origins of Adult Lung Disease as Opportunities for Prevention.

Prenatal and childhood exposures have been shown to impact lung development, lung function trajectory, and incidence and prevalence of respiratory disease. Early life may serve as a window of susceptibility to such exposures, with the potential to influence lifelong respiratory health. Risk factors encountered in early life with potentially durable impact on lung health include prematurity, respiratory viral illness, allergen sensitization and exposure, tobacco use and exposure, indoor and outdoor pollution, diet, and obesity. These exposures vary in the extent to which they are modifiable, and interventions aimed at reducing harmful exposures range from individual-level behavior modification to policy initiatives implemented to promote population health. For many exposures, including tobacco-related exposures, multilevel interventions are needed. Future research is needed to provide insight as to early-life interventions to promote optimal lung growth and prevent development of chronic respiratory disease. Clinicians should play an active role, assisting individual patients in avoiding known detrimental exposures including maternal smoking during pregnancy and initiation of active smoking. Clinicians can be empowered by evidence to support policies promoting reduction of population-level risk factors, such as restriction on electronic cigarette sales and legislation to uphold air quality standards, to encourage attainment of maximal lung function and reduce risk of chronic lung disease.

Do Baseline Asthma and Allergic Sensitization Characteristics Predict Responsiveness to Mouse Allergen Reduction?

BACKGROUND: Mouse allergen reduction is associated with improvements in asthma among sensitized and exposed children, but whether clinical characteristics predict responsiveness to allergen reduction is unclear. OBJECTIVE: To examine the effects of clinical characteristics on relationships between mouse allergen reduction and asthma outcomes. METHODS: We performed a secondary analysis of data from a randomized clinical trial of a mouse allergen intervention, examining the effects of atopy, demographic characteristics, lung function, asthma control, and asthma severity on relationships between mouse allergen reduction and asthma outcomes. RESULTS: Participants were predominantly low-income and minority (78% black, 22% Hispanic), and had persistent asthma. Among less atopic participants (<6 positive skin prick test results), each 50% reduction in mouse allergen was associated with fewer symptoms (incidence rate ratio [95% CI]: maximal symptoms: 0.94 [0.92-0.96]). There was little effect of mouse allergen reduction on symptoms among more atopic participants (P > .05). The interactions between atopic status and mouse allergen reduction were statistically significant for all symptom outcomes; however, there was no evidence that atopic status influenced the effect of mouse allergen reduction on exacerbation-related outcomes. Older children (≥9 years) tended to experience greater improvement in some asthma outcomes with reduction in mouse allergen exposure than younger children. There was no evidence that either mouse-specific IgE or lung function influenced the effect of mouse allergen reduction on any asthma outcomes. CONCLUSIONS: Although there may be variability in the clinical response to mouse allergen reduction among low-income, minority children with asthma, there were no clinical characteristics that clearly identified a subgroup at which the intervention should be targeted.

Reduction in mouse allergen exposure is associated with greater lung function growth.

BACKGROUND: Current childhood asthma therapies have little effect on lung function trajectory. OBJECTIVE: We sought to determine whether mouse allergen exposure reduction is associated with lung function growth in mouse-sensitized/exposed asthmatic children. METHODS: Three hundred fifty mouse-sensitized/exposed asthmatic children (5-17 years old) were enrolled in a 1-year randomized trial of integrated pest management plus education versus education alone. Prebronchodilator/postbronchodilator spirometry was performed at baseline and 6 and 12 months, and bedroom floor mouse allergen levels were measured every 3 months. Mouse allergen reduction was defined as a 75% or greater decrease in mouse allergen levels from baseline. Treatment groups were combined for analyses because there were no differences in outcomes between groups. Changes in lung function over time were modeled, adjusting for age, sex, race, atopy, group, and bronchodilator reversibility and including an interaction term (allergen reduction*time). RESULTS: The study population was predominantly black (79.4%) and low income (66.3% [<$30,000]). At baseline, the median mouse allergen level was 5.7 µg/g (interquartile range, 1.5-22.8 µg/g), and the mean (SD) prebronchodilator FEV1/forced vital capacity ratio was 80.2% (9.0%). Ninety-two (26.3%) participants had 75% or greater reduction in mouse allergen levels. For a 10-year-old black boy, 75% or greater allergen reduction was associated with an increase in prebronchodilator FEV1 of 238 mL/y (95% CI, 177-299 mL/y), whereas less than 75% allergen reduction was associated with an increase in prebronchodilator FEV1 of 131 mL/y (95% CI, 97-166 mL/y). Estimated differences in prebronchodilator and postbronchodilator FEV1 growth were as follows: 107 mL/y (95% CI, 37-177 mL/y; Pint = .003) and 48 mL/y (95% CI, -17 to 113 mL/y; Pint = .15), respectively. Estimated differences in prebronchodilator and postbronchodilator forced expiratory flow at 25% to 75% of vital capacity growth were as follows: 182 mL/y (95% CI, 61-304 mL/y; Pint = .003) and 181 mL/y (95% CI, 48-314 mL/y; Pint = .008), respectively. CONCLUSION: Mouse allergen reduction is associated with greater increases in prebronchodilator FEV1 and prebronchodilator/postbronchodilator forced expiratory flow at 25% to 75% of vital capacity over 1 year among sensitized/exposed asthmatic children.

Sampling Devices for Indoor Allergen Exposure: Pros and Cons.

PURPOSE OF REVIEW: To review current indoor allergen sampling devices, including devices to measure allergen in reservoir and airborne dust, and personal sampling devices, with attention to sampling rationale and major indoor allergen size and characteristics. RECENT FINDINGS: While reservoir dust vacuuming samples and airborne dust volumetric air sampling remain popular techniques, recent literature describes sampling using furnace filters and ion-charging devices, both which help to eliminate the need for trained staff; however, variable correlation with reservoir dust and volumetric air sampling has been described. Personal sampling devices include intra-nasal samples and personal volumetric air samples. While these devices may offer better estimates of breathable allergens, they are worn for short periods of time and can be cumbersome. Reservoir dust sampling is inexpensive and is possible for families to perform. Airborne dust sampling can be more expensive and may better quantify cat, dog, and mouse allergen exposure. Personal sampling devices may offer a better representation of breathable air.

Caregiver-Reported Asthma Control Predicts Future Visits, Independent of Guideline-Based Control Measures.

BACKGROUND: It is unknown whether caregiver perception of a child's asthma control, independent of guideline-based asthma control assessment, is a predictor of future acute visits. OBJECTIVE: To determine whether caregiver-reported asthma control is an indicator of future risk of acute visit. METHODS: Two study populations of low-income, minority 5- to 17-year-old children with persistent asthma were included. Questionnaires administered at baseline and at 3, 6, 9, and 12 months captured symptoms, short-acting ß-agonist use, acute visits in the previous 3 months, and caregiver-reported asthma control. Well-controlled, not well-controlled, and very poorly controlled asthma were defined using National Asthma Education and Prevention Program guideline-based assessment. Relationships between caregiver-reported control and acute visits in the subsequent 3 months were examined. RESULTS: At baseline, both populations were predominantly black/African American (91% and 79%) with public insurance (85% and 88%) and very poorly controlled asthma (47% and 50%). In both populations, most caregivers reported that their child's asthma was well controlled (73% and 69%). In both populations, participants whose caregivers reported that their child had uncontrolled asthma had greater odds of having an acute visit in the following 3 months as compared with participants whose caregivers reported that their child's asthma was well controlled, independent of guideline-based control, age, sex, race, controller medication, insurance, and atopy (odds ratio [95% CI], 2.4 [1.4-4.2] and 1.6 [1.1-2.4]). CONCLUSIONS: Among predominantly low-income minority children with asthma, caregiver-reported asthma control may provide information about the risk of future acute visit for asthma that is complementary to guideline-based control assessment.

Physician-diagnosed eczema is an independent risk factor for incident mouse skin test sensitization in adults.

BACKGROUND: The disrupted skin barrier in eczema has been associated with an increased risk of immunoglobulin E (IgE) sensitization in childhood. However, it is unclear whether eczema, independent of atopy, is a risk factor for the development of allergic sensitization in adulthood. OBJECTIVE: To determine if skin barrier dysfunction, independent of atopy, is a risk factor for incident sensitization in adult workers at a mouse production and research facility. METHODS: New employees at The Jackson Laboratory enrolled in a cohort study and underwent skin-prick testing (SPT) at baseline and every 6 months to mouse and to a panel of aeroallergens (net wheal ≥3 mm indicated a positive SPT result). Mouse allergen exposure was measured every 6 months by using personal air monitors. Physician-diagnosed eczema was defined as self-reported physician-diagnosed eczema. Cox proportional hazard modeling was used to examine the association between baseline physician-diagnosed eczema and incident mouse skin test sensitization and adjusted for potential confounders. RESULTS: The participants (N = 394) were followed up for a median of 24 months. Fifty-four percent were women, 89% were white, and 64% handled mice. At baseline, 7% of the participants reported physician-diagnosed eczema and 9% reported current asthma; 61% had at least one positive skin test result. At 30 months, 36% of those with eczema versus 14% of those without eczema had developed a positive mouse skin test result (p = 0.02, log-rank test). After adjusting for age, race, sex, smoking status (current, former, never), current asthma, hay fever, the number of positive SPT results at baseline, and mouse allergen exposure, physician-diagnosed eczema was an independent risk factor for incident mouse SPT sensitization (hazard ratio 5.6 [95% confidence interval, 2.1-15.2]; p = 0.001). CONCLUSION: Among adult workers at a mouse production and research facility, physician-diagnosed eczema was a risk factor for incident mouse sensitization, independent of atopy, which indicated that a defect in skin barrier alone may increase the risk of skin sensitization, not just in childhood, but throughout life.

Mouse Sensitization and Exposure Are Associated with Asthma Severity in Urban Children.

BACKGROUND: Mouse sensitization and exposure are associated with uncontrolled asthma, but whether they are associated with asthma severity, an intrinsic disease characteristic and long-term outcome predictor, is unclear. OBJECTIVE: To examine relationships between mouse sensitization and/or exposure and asthma severity in urban children. METHODS: A total of 645 children (5-17 years) with uncontrolled asthma underwent mouse sensitization evaluation. Sensitized children had mouse allergen measured in bedroom dust. Relationships between mouse sensitization, allergen levels, and asthma severity measures (treatment step and Composite Asthma Severity Index [CASI]) were examined using regression models adjusted for age, sex, atopy, study site, race, ethnicity, and insurance. RESULTS: The study population was predominantly minority (69.6% black, 20.8% Hispanic), low income (61.8%), and mouse sensitized (54.4%). Mean ± SD treatment step was 3.2 ± 1.6, equivalent to medium-dose inhaled corticosteroid. Mean ± SD CASI was 6.5 ± 3.4, reflecting moderate persistent asthma. Mouse sensitization was associated with higher treatment step (3.5 vs 2.9, mouse-sensitized vs nonsensitized, P < .001), independent of potential confounders (ß [95% CI], 0.36 [0.07-0.64]; P = .01). Mouse sensitization was associated independently with CASI (ß [95% CI], 0.82 [0.16-1.47]; P = .02). Among mouse-sensitized participants, higher bedroom floor and bed Mus m 1 were independently associated with treatment step (ß [95% CI], 0.26 [0.09-0.43]; P = .002 and ß [95% CI], 0.22 [0.01-0.43]; P = .04), respectively. Higher bedroom floor Mus m 1 was independently associated with CASI (ß [95% CI], 0.43 [0.05-0.81]; P = .03). CONCLUSIONS: Mouse sensitization and exposure are associated with asthma severity, among low-income, minority children. Further studies are needed to determine whether reducing allergen exposure among mouse-sensitized patients with asthma can reduce severity, ultimately altering childhood asthma natural history.