Factors Influencing Pediatric Asthma into Adulthood (FIPA2)

Missouri Breaks Research, Inc., Timber Lake SD

Investigators

Abstract

A. Summary of Funded Parent Grant: Factors Influencing Pediatric Asthma into Adulthood (R01MD019027) The prevalence of asthma among American Indian (AI) children is 9.3% as compared to 5.5% in non- Hispanic White children. Asthma disparities become even more pronounced into adulthood, with AI adults having the highest prevalence of asthma as compared to all other racial/ethnic groups in the US, with 60% uncontrolled. Asthma is influenced by social and environmental factors (SEF) including adverse childhood events (ACEs), tobacco smoke, and everyday life stressors that may alter immunological state. ACEs in particular, including abuse, neglect, and household challenges have been associated with immune dysregulation, may have implications for clinical outcomes of respiratory viral infections in children that have been linked to asthma and persistent respiratory symptoms. For example, Infants who develop severe RSV bronchiolitis in the first year of life are more likely to develop asthma, and children with asthma are at increased risk of experiencing complications from respiratory viral infections due to SARS-CoV-2, respiratory syncytial virus (RSV), influenza, and rhinovirus C. In the Factors Influencing Pediatric Asthma (FIPA) study including children from a Northern Plains American Indian community, we found children with asthma experienced an increased clinical burden from RSV infection and had lower levels of serum RSV-specific Immunoglobulin G (IgG) than children without asthma, indicative of immune suppression or dysfunction. However, the complex interplay between social, environmental and immunological response to viral respiratory infections remains largely unknown, and these factors have not been investigated among AI children with respect to their influence on immunological response and asthma development and control of asthma symptoms. In this continued AI community-focused study, we will test the hypothesis that social and environmental factors contribute to asthma susceptibility through stress-induced immune dysregulation, including the alteration of immunological response to viral respiratory infections. We will also investigate the role of viral respiratory infections and SEF on asthma control, including frequency of symptoms, exacerbations, ER visits/hospitalizations, and use of asthma medications. Aim 1: Identify social and environmental factors (SEF) that contribute to asthma susceptibility, asthma control, and long-term respiratory health in American Indian children. We will follow-up on our previously NIMHD-funded case/control study of 324 children recruited between the ages of 6-17 from 2013- 2017 as they transition into adulthood (now ages 11-27). We will recontact original study participants, evaluating their current asthma status to investigate the role of age and gender on long-term respiratory health including current asthma and asthma control. We will also expand our study to 400 new participants with and without asthma between the ages of 6-17, including Tribal members living in Rapid City, SD, and offspring of original study participants (~30% of original study participants have since become parents). We will obtain detailed measures of SEF, and retrospective information on adverse childhood events (ACE) using an established screener to evaluate their role in asthma susceptibility and asthma control, including comparisons between urban vs. rural and multi-generational effects in this community-engaged study. We hypothesize that domains of biological and behavioral influences acting on the individual and interpersonal levels generate social stress and have an impact on asthma development and control. Aim 2: Investigate the role of SEF on immunological response to viral respiratory infections (VRIs) in AI children with and without asthma. We will investigate the impact of social and environmental factors measured using validated and Tribally-developed surveys on the immune system of AI children with and without asthma, including response to viral respiratory infections (viral-specific serum IgG and IgM concentrations to RSV and other VRI pathogens known to cause long-term respiratory sequelae). We will quantify serological measurements of participants’ humoral immune responses including serum biomarkers of inflammation (Th1/Th2/Th17 cytokines), atopy (serum total IgE), and total immunoglobulins. We will test our hypothesis that interactions with detailed survey measures of SEF with immunological and clinical outcomes of VRIs, including viral responses in participants with and without asthma are the strongest and most significant predictors in our AI participants. Aim 3: Engage with an existing Tribal Community Advisory Board (CAB) using continuous bidirectional process evaluation to develop an intervention and policy framework of asthma prevention. We will engage with the CRST’s dedicated community and Tribal cultural experts and active volunteers in building our local CAB. We will leverage the scientific knowledge gained under this proposal to work with the CAB to create a sustainable, feasible, and Lakota-driven, intervention and policy framework, including the creation of structures to allow integration of social stressers including ACEs into existing referral services and policy initiatives. We will collect detailed information using questionnaires and semi-structured interviews among CAB members and the community about the study development and processes. We recognize that Tribal children with mild, moderate to severe asthma who are experiencing humoral immune response alterations and a combination of SEFs need very targeted and specialized preventive measures that this study will be able to develop and support with implementation. B. RESEARCH PLAN: Environmental Toxicants and Asthma in American Indian Children Background: Viral respiratory infections in early life have been linked to the development of asthma and persistent respiratory symptoms in children 1–3, including respiratory syncytial virus (RSV) of which the majority of children are exposed before age 2. Infants who develop RSV bronchiolitis in the first year of life have a high chance of developing asthma 4, and children with asthma have an increased risk of experiencing complications and lasting respiratory symptoms from infections such as RSV, SARS-CoV-2, influenza, and rhinovirus-C 5–8. The prevalence of asthma among American Indian (AI) children is 9.3% as compared to 5.5% in non-Hispanic White children 9. This is a serious but understudied, pediatric health disparity in the U.S. that becomes even more pronounced into adulthood, with AI adults having the highest prevalence of asthma as compared to all other racial/ethnic groups 9. Asthma has been linked to a number of social and environmental factors 10–15 including exposure to social stress, tobacco smoke, air pollution, and environmental toxicants including per- and perfluoroalkyl substances (PFAS) 16. There is mounting evidence that PFAS, a “forever chemical” in the environment has a deleterious effect on many aspects of health 17, including thyroid and immune activity 18, inflammation in pregnancy 19, fetal growth 20, immune response to childhood vaccines 21 and viral respiratory infections 22,23. Thus, exposure to PFAS and environmental toxins during childhood may have a lasting effect on Tribal health. In summary, we propose to address newly emerging chemical exposures including PFAS in an at-risk, low income, Native American community in consultation with the Cheyenne River Sioux Tribe (CRST), including children living in Rapid City South Dakota and the Cheyenne River Sioux and Oglala Lakota Reservations. In this area of South Dakota, the proportion of children living below the Federal poverty line is 47% and 57% in Ziebach 24 and Dewey 25 Counties, respectively. The adverse health effects of PFAS and environmental toxins due to community-level exposure in this area of high childhood poverty has yet to be investigated, nor their effects on immunological response to viral respiratory infections and immune dysfunction. Preliminary Research: In the Factors Influencing Pediatric Asthma (FIPA) study we found that AI children with asthma living on the Cheyenne River Sioux and Oglala Lakota Reservations were more likely to reside in multi-unit housing, and in residences with rodent or insect infestation resulting in poor indoor air quality as compared to asthma controls 26. Children with asthma also had higher BMI, total leukocyte counts, % eosinophils, total serum IgE, and specific IgE to five common indoor airborne antigens 27. We also found children with asthma to have lower levels of RSV-specific IgG during the winter (Figure 1) and to report increased hospitalizations and RSV diagnoses (Figure 2), suggesting immune dysregulation with clinical implications 28. We hypothesize that exposures to environmental toxins, some of which have been linked to immune dysregulation may play an important role. Figure 1: A. Asthma cases recruited during the winter (RSV season) had significantly lower RSV IgG as compared to asthma cases recruited during the summer (p=2.5x10-6). There was no observed difference in seasonality for asthma controls (p=0.60). B. More children with asthma have low levels of IgG (<40 IU/mL). In unpublished results, Dr. Erdei (co-PI of parent study) detected PFAS in 83% of samples from 50 CRST adults who fish regularly from the Tribe's main public water sources. She has identified an association between PFAS and a number of tissue- specific and antinuclear autoantibodies, and found serum PFAS and other compounds to be predictors of autoimmune markers indicative of a hyperreactive immune response in adults (Figure 3). Consuming locally caught fish as part of AI Figure 2: Children with asthma in the FIPA study report a higher culture and as a dietary source of protein was also clinical burden from RSV. associated with overall elevation of serum PFAS. Similar investigations among children in the CRST will allow us to learn more about PFAS exposure patterns as it relates to immune dysregulation, viral respiratory infections, and its effect on children’s health in the community. Figure 3: Quantile Regression plots in CRST adults showing that A. Perfluorononanoic acid (PFNA) exposures are predictive of anti- native DNA response. B. PFOS and C. PFOA exposures are predictive of thyroid-specific (anti-thyroglobulin) autoimmune response, with PFOA having an immunosuppressive effect. In summary, we hypothesize that exposure to environmental toxins, specifically PFAS, contributes to immune dysregulation and response to viral respiratory infections in American Indian children with asthma. As recruitment for FIPA2 is starting, this is an opportune time for Dr. Spear to lead a study investigating the role of PFAS and environmental toxins on the health of AI children. This opportunity will afford Dr. Spear to narrow in on the role of PFAS on immune dysregulation and response to viral respiratory infections in children with and without asthma, while making new connections with scientists in the field of environmental research. Overall, our study will advance knowledge of the effect of environmental toxins on immune dysregulation of children to inform future policies and interventions. Thus, our specific aims for this diversity supplement are: Specific Aim 1: Measure and identify suspect and PFAS chemicals that are present in American Indian children from Rapid City and the Cheyenne River Sioux/Oglala Lakota Reservations. Specific Aim 2: Perform correlative and predictive modeling between PFAS/suspect chemicals and immunological biomarkers and response to viral respiratory infections in AI children with and without asthma. Approach: We will perform suspect screening and test for levels of 12 PFAS in serum samples of 52 children with and without asthma and living in urban vs. rural (Reservation) locations (Figure 4). We will identify suspect chemicals present in AI children, and perform preliminary correlations with immune biomarkers, viral-specific immunoglobulins, PFAS and suspect chemicals identified. Characterizing the presence and effect of environmental toxins on the immune system is an essential step for understanding environmental health disparities, which the community has been struggling with for decades. Figure 4: Location and summary of serum samples for study to measure PFAS/suspect chemicals in children ages 6-17 years old in FIPA2. Recruitment is beginning 5/2024. We also have stored samples for >300 original FIPA participants at -80C (living on Reservation, only). Specific Aim 1: Measure and identify suspect and PFAS chemicals that are present in American Indian children from Rapid City and the Cheyenne River Sioux/Oglala Lakota Reservations. We will work with the UCSF Bioassay Facility Core to develop a protocol for PFAS and untargeted suspect screening of serum samples from 52 AI children, including 26 asthma cases and 26 matched controls living in an urban (Rapid City SD) vs. rural (Reservation) environment. Specific Aim 2: Perform correlative and predictive modeling between PFAS/suspect chemicals and immunological biomarkers and response to viral respiratory infections in AI children with and without asthma. We will test for a correlation of PFAS/suspect chemicals with levels of immune biomarkers and viral- specific immunoglobulins. Immune biomarkers will include cytokines, Creactive protein, CBCs (white blood cell counts), total serum IgE, and viral specific IgG/IgM (SARs-CoV2, RSV, influenza, and rhinovirus C). Results from this aim will provide insights in to 1) the variability in exposure to environmental toxicants in children living in urban vs. rural (Reservation) locations and 2) the role of exposure to PFAS/suspect chemicals on immune dysregulation and asthma. Statistical analyses: We will examine the distribution of individual PFAS chemicals plus untargeted suspect chemicals to determine the relevant statistical test. In general, for commonly detected chemicals we will utilize linear and logistic regression models (or nonparametric tests) to test for associations between PFAS/suspect chemicals adjusting for multiple covariates selected through an iterative process (e.g. BMI, sex, household size, asthma medications); we will also contrast models with and without an asthma interaction. For rare chemicals we will apply a fisher’s exact test for detected/undetected. ROC curves will be generated for individual chemicals by asthma and location, and cluster analyses will be performed over all chemicals using a principal component analysis (with UMAP projection) and partial least-squares discriminant analysis (PLS-DA) for predictive modeling and Cox regression. Lastly, we will attempt a mediation analysis to evaluate if exposure to PFAS/suspect chemicals contributes to asthma via immune dysregulation. Relevance to the parent grant: The parent grant is centered on identifying social determinants of the environment including adverse childhood experiences that contribute to the development of asthma through altering the immunological response to viral respiratory infections. However, there is substantial evidence to suggest that exposure to environmental toxicants contribute to immune dysregulation in both the context of asthma and general immune function as discussed above. In this proposal, Dr. Spear will focus on the physical environment, specifically the role of exposure and accumulation of environmental toxicants on immune dysregulation in children with and without asthma.