Phthalate biomarkers and associations with respiratory symptoms and healthcare utilization among low-income urban children with asthma

Associations of prenatal exposure to phthalates and their mixture with lung function in Mexican children

Early life phthalates exposure has been associated with adverse respiratory outcomes. However, evidence linking prenatal phthalates exposure and childhood lung function has been inconclusive. Additionally, few studies have examined phthalates exposure as a mixture and explored sexually dimorphic associations. We aimed to investigate sex-specific associations of prenatal phthalates mixtures with childhood lung function using the PROGRESS cohort in Mexico (N = 476). Prenatal phthalate concentrations were measured in maternal urine collected during the 2nd and 3rd trimesters. Children's lung function was evaluated at ages 8-13 years. Individual associations were assessed using multivariable linear regression, and mixture associations were modeled using repeated holdout WQS regression and hierarchical BKMR; data was stratified by sex to explore sex-specific associations. We identified significant interactions between 2nd trimester phthalates mixture and sex on FEV1 and FVC z-scores. Higher 2nd trimester phthalate concentrations were associated with higher FEV1 (β = 0.054, 95 %CI: 0.005, 0.104) and FVC z-scores (β = 0.074, 95 % CI: 0.024, 0.124) in females and with lower measures in males (FEV1, β = -0.017, 95 %CI: -0.066, 0.026; FVC, β = -0.014, 95 %CI: -0.065, 0.030). This study indicates that prenatal exposure to phthalates is related to childhood lung function in a sex-specific manner.

Recent use of consumer and personal care products and exposures to select endocrine disrupting chemicals among urban children with asthma

BACKGROUND

Emerging studies suggest that endocrine disrupting chemicals (EDCs) in personal care and other consumer products are linked with various adverse health effects, including respiratory and reproductive effects. Despite Black persons using more personal care products than other demographic groups and having a high asthma burden, little is known regarding their consumer product use patterns and associated EDC exposures.

OBJECTIVE

To examine the association between recent exposure to select EDCs with specific consumer products and behaviors in a cohort of 110 predominantly Black children with asthma, ages 8-17 years, living in Baltimore City, Maryland.

METHODS

We quantified concentrations of bisphenol A (BPA), bisphenol S (BPS), bisphenol F, two dichlorophenols, four parabens, triclosan, benzophenone-3, and triclocarban in spot urine samples. Questionnaires were used to capture recent (last 24-h) consumer product use and behaviors. Associations between EDCs and consumer product uses/behaviors were assessed using multivariable linear regression, adjusting for age, gender, race/ethnicity, and caregiver income level. Effect estimates were expressed as geometric mean ratios of biomarker concentrations of product-users vs non-users.

RESULTS

Increased concentrations to select EDCs were associated with recent use of air freshener (ratios; BPA: 1.9, 95%CI 1.4-2; BPS 1.7, 95%CI 1-2.97; propyl paraben: 3.0, 95%CI 1.6-5.6), scented candles (methyl paraben: 2.6, 95%CI 1.1-6.1), and scented carpet powder (2,5-dichlorophenol: 2.8, 95%CI 1.2-6.3). Additionally, consuming canned food was associated with some increased biomarker concentrations (ratios: BPA: 1.7, 95%CI 1.2-2.4; BPS: 2.1, 95% CI: 1.2-3.6).

SIGNIFICANCE

These findings add to the body of evidence suggesting that recent use of select consumer products in Black children contributes to exposure of chemicals of concern and could potentially inform exposure mitigation interventions. Findings have broad potential health implications for pediatric populations and Black children who may face exposure and health disparities.

IMPACT

Little is known about how children's personal care product use and consumer behaviors affect their exposures to endocrine disrupting chemicals (EDCs). This is particularly true for Black children who often experience a disparate exposure burden to many EDCs. This is a significant knowledge gap among children that are uniquely vulnerable to EDCs as they undergo critical windows of growth and development. Our findings show associations between consumer products and EDC exposures in predominantly Black children in low-income settings. Identifying EDC exposure determinants has broad health implications as many of these chemicals have been associated with adverse health risks.

Recent Insights into the Environmental Determinants of Childhood Asthma

PURPOSE OF REVIEW

Ubiquitous environmental exposures, including ambient air pollutants, are linked to the development and severity of childhood asthma. Advances in our understanding of these links have increasingly led to clinical interventions to reduce asthma morbidity.

RECENT FINDINGS

We review recent work untangling the complex relationship between air pollutants, including particulate matter, nitrogen dioxide, and ozone and asthma, such as vulnerable windows of pediatric exposure and their interaction with other factors influencing asthma development and severity. These have led to interventions to reduce air pollutant levels in children's homes and schools. We also highlight emerging environmental exposures increasingly associated with childhood asthma. Growing evidence supports the present threat of climate change to children with asthma. Environmental factors play a large role in the pathogenesis and persistence of pediatric asthma; in turn, this poses an opportunity to intervene to change the course of disease early in life.

Exposure to endocrine-disrupting plasticisers and lung function in children and adolescents: A systematic review and meta-analysis

Exposure to endocrine-disrupting plasticisers (EDPs), such as phthalates and bisphenols, has been associated with reduced lung function in children and adolescents. However, the existing literature yields conflicting results. This systematic review and meta-analysis aimed to assess the epidemiologic evidence investigating the association between EDP exposure and lung function in children and adolescents. A comprehensive search of five databases identified 25 relevant studies. We employed a random-effects meta-analysis on spirometry measures. The effect size of interest was the change in lung function in standard deviation (SD) units resulting from a two-fold increase in exposure levels. We found that certain phthalates marginally reduced lung function in children. Forced expiratory volume in 1 s (FEV1) was reduced by a two-fold increase in mono-benzyl phthalate (MBzP) (β = -0.025 SD, 95%CI: 0.042, -0.008), mono-ethyl-oxo-hexyl phthalate (MEOHP) (β = -0.035 SD, 95%CI: 0.057, -0.014) and mono-carboxy-nonyl phthalate (MCNP) (β = -0.024 SD, 95%CI: 0.05, -0.003). Forced vital capacity (FVC) was decreased by a two-fold increase in MBzP (β = -0.022 SD, 95%CI: 0.036, -0.008) and MEOHP (β = -0.035 SD, 95%CI: 0.057, -0.014) levels. A two-fold increase in MCNP levels was associated with lower FEV1/FVC (β = -0.023 SD, 95%CI: 0.045, -0.001). Furthermore, a two-fold increase in MEOHP levels reduced forced mid-expiratory flow (FEF25-75) (β = -0.030 SD, 95%CI: 0.055, -0.005) and peak expiratory flow (PEF) (β = -0.056 SD, 95%CI: 0.098, -0.014). Notably, associations were more pronounced in males. Given the potential for reverse causation bias, the association between childhood exposure to EDPs and lung function remains uncertain. Overall, our meta-analysis showed small reductions in lung function with higher phthalate exposure. However, future studies are warranted in younger age groups.

Biological Impact of Organic Extracts from Urban-Air Particulate Matter: An In Vitro Study of Cytotoxic and Metabolic Effects in Lung Cells

Atmospheric particulate matter (PM) with diameters below 10 µm (PM10) may enter the lungs through inhalation and are linked to various negative health consequences. Emergent evidence emphasizes the significance of cell metabolism as a sensitive target of PM exposure. However, the current understanding of the relationship between PM composition, conventional toxicity measures, and the rewiring of intracellular metabolic processes remains limited. In this work, PM10 sampled at a residential area (urban background, UB) and a traffic-impacted location (roadside, RS) of a Portuguese city was comprehensively characterized in terms of polycyclic aromatic hydrocarbons and plasticizers. Epithelial lung cells (A549) were then exposed for 72 h to PM10 organic extracts and different biological outcomes were assessed. UB and RS PM10 extracts dose-dependently decreased cell viability, induced reactive oxygen species (ROS), decreased mitochondrial membrane potential, caused cell cycle arrest at the G0/G1 phase, and modulated the intracellular metabolic profile. Interestingly, the RS sample, richer in particularly toxic PAHs and plasticizers, had a greater metabolic impact than the UB extract. Changes comprised significant increases in glutathione, reflecting activation of antioxidant defences to counterbalance ROS production, together with increases in lactate, NAD+, and ATP, which suggest stimulation of glycolytic energy production, possibly to compensate for reduced mitochondrial activity. Furthermore, a number of other metabolic variations hinted at changes in membrane turnover and TCA cycle dynamics, which represent novel clues on potential PM10 biological effects.

Defining and Promoting Pediatric Pulmonary Health: Assessing Lung Function and Structure

Lifelong respiratory health is rooted in the structural and functional development of the respiratory system in early life. Exposures and interventions antenatally through childhood can influence lung development into young adulthood, the life stage with the highest achievable lung function. Because early respiratory health sets the stage for adult lung function trajectories and risk of developing chronic obstructive pulmonary disease, understanding how to promote lung health in children will have far reaching personal and population benefits. To achieve this, it is critical to have accurate and precise measures of structural and functional lung development that track throughout life stages. From this foundation, evaluation of environmental, genetic, metabolic, and immune mechanisms involved in healthy lung development can be investigated. These goals require the involvement of general pediatricians, pediatric subspecialists, patients, and researchers to design and implement studies that are broadly generalizable and applicable to otherwise healthy and chronic disease populations. This National Institutes of Health workshop report details the key gaps and opportunities regarding lung function and structure.

Co-exposure to polystyrene microplastics and di-(2-ethylhexyl) phthalate aggravates allergic asthma through the TRPA1-p38 MAPK pathway

Increasing attention has been paid to the potential impact of microplastics (MPs) pollution on human health. MPs and phthalates coexist in the environment, however, the effects of exposure to MPs alone or to a combination of di-(2-ethylhexyl) phthalate (DEHP) and MPs on allergic asthma are unclear. This study investigates the effects of exposure to polystyrene microplastics (PS-MPs) or co-exposure with DEHP, on allergic asthma, and the underlying molecular mechanisms. We established an allergic asthma model using ovalbumin, and mice were exposed to PS-MPs (5 mg/kg bw/day) alone, or combined with DEHP (0.5, 5 mg/kg bw/day), for 28 days. The results showed that in the presence of ovalbumin (OVA) sensitization, exposure to PS-MPs alone slightly affected airway inflammation, and airway hyperresponsiveness, while co-exposure to PS-MPs and DEHP caused more significant damage. Co-exposure also induced more oxidative stress and Th2 immune responses, and activation of the TRPA1 and p38 MAPK pathways. The aggravation of asthmatic symptoms induced by co-exposure to PS-MPs and DEHP were inhibited by blocking TRPA1 ion channel or p38 MAPK pathway. The results demonstrated that co-exposure to PS-MPs and DEHP exacerbates allergic asthma, by exacerbating oxidative stress and inflammatory responses, and activating the TRPA1-p38 MAPK pathway.

Socioeconomic determinants of asthma health

PURPOSE OF REVIEW

The current review provides an assessment of the recent pediatric literature evaluating socioeconomic drivers of asthma incidence and morbidity. The review addresses the specific social determinants of health related to housing, indoor and outdoor environmental exposures, healthcare access and quality, and the impact of systematic racism.

RECENT FINDINGS

Many social risk factors are associated with adverse asthma outcomes. Children living in low-income, urban neighborhoods have greater exposure to both indoor and outdoor hazards, including molds, mice, second-hand smoke, chemicals, and air pollutants, all of which are associated with adverse asthma outcomes. Providing asthma education in the community - via telehealth, school-based health centers, or peer mentors - are all effective methods for improving medication adherence and asthma outcomes. The racially segregated neighborhoods created by the racist 'redlining' policies implemented decades ago, persist today as hotspots of poverty, poor housing conditions, and adverse asthma outcomes.

SUMMARY

Routine screening for social determinants of health in clinical settings is important to identify the social risk factors of pediatric patients with asthma. Interventions targeting social risk factors can improve pediatric asthma outcomes, but more studies are needed related to social risk interventions.

Exposures to Organophosphate Esters and Respiratory Morbidity among School-Aged Children with Asthma

Organophosphate esters (OPEs) are an emerging class of chemicals used in a variety of consumer products as flame retardants, plasticizers, and additives. While prior epidemiologic studies suggest that OPEs may impact respiratory health, results remain inconclusive. We examined associations between urinary biomarkers of OPEs and symptoms of respiratory morbidity in a panel study of 147 predominantly Black school-aged children with asthma living in Baltimore City, Maryland. The study consisted of up to four seasonal, week-long, in-home visits where urine samples and self-reported asthma symptoms were collected on days 4 and 7 (n_samples = 438). We quantified concentrations of nine urinary OPE biomarkers: bis(2-chloroethyl) phosphate (BCEtp), bis(1-chloro-2-propyl) phosphate (BCPP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), di-n-butyl phosphate (DBuP), di-benzyl phosphate (DBzP), di-o-cresylphosphate (DOCP), di-p-cresylphosphate (DPCP), di-(2-propylheptyl) phthalate (DPHP), and 2,3,4,5-tetrabromo benzoic acid (TBBA). We estimated prevalence odds ratios (POR) of respiratory morbidity symptoms using logistic regression with generalized estimating equations to account for our repeated measure design. We assessed BDCIPP and DPHP as continuous (log₂) concentrations and dichotomized exposure of BCEtP, DBuP, and DPCP (detect vs non-detect) based on their lower detection frequencies. We adjusted models for season, visit day, age, gender, caregiver education, health insurance type, exposure to household smoking, atopy, and PM_2.5. Higher DPHP concentrations were significantly associated with odds of daytime symptoms (POR: 1.26; 95% CI: 1.04-1.53; p = 0.02) where daytime symptoms consisted of trouble breathing due to asthma, reporting bother caused by asthma, and/or limitation in activities due to asthma. DBuP detection was associated with use of rescue medication on the day of sample collection (POR: 2.36; 95% CI: 1.05-5.29; p = 0.04). We also observed several consistent, albeit non-significant (p > 0.05), positive associations for BCEtP and DPCP and respiratory morbidity measures. This is the first study to evaluate the relationship between OPE biomarkers and respiratory morbidity symptoms in children with asthma, and findings suggest that further studies are warranted to confirm whether these associations are causal.

Environment and the development of severe asthma in inner city population

PURPOSE OF REVIEW

Higher asthma prevalence and morbidity are seen in inner-city areas, disproportionately affecting low-income families living in substandard housing. Children within these families experience more frequent asthma exacerbations, acute care and emergency department visits, and hospitalizations, thus characterizing severe asthma. In this review, we assess recent published literature focused on indoor and outdoor exposures that contribute to the development and morbidity of asthma.

RECENT FINDINGS

Many urban environmental exposures contribute to asthma burden, including tobacco/e-cigarette smoke, pest allergens, molds, and possibly synthetic chemicals such as phthalates and bisphenol A, radon, and volatile organic compounds. Individuals living in inner-city areas also experience higher levels of air pollutants and ambient heat, further perpetuating asthma incidence and severity.

SUMMARY

This article summarizes the latest advances and provides direction for future research on risk factors, interventions, and public policy to help alleviate the burden of asthma due to urban environment exposures.

Microbiome alterations associated with phthalate exposures in a US-based sample of Latino workers

Low-wage service sector jobs are largely occupied by racial/ethnic minority workers who often experience an increased risk of elevated chemical exposures, including chemicals like phthalates, compared to the general public. Phthalates have been linked with adverse health effects, including increased risk of atopy and asthma. An important etiological component in respiratory disease, including asthma, is the role of the upper respiratory microbiota in atopic disease development. However, it is unclear how the upper respiratory microbiome is affected by chemical exposures, and how this may impact respiratory outcomes. As Latino workers are often disproportionately exposed to increased concentrations of chemicals and Hispanics have higher rates of adverse respiratory health conditions such as asthma, the aim of this pilot study was to evaluate the effects of 10 unique phthalate urinary biomarkers on the 16S rRNA nasal microbiome. Nasal and urinary samples were collected from 20 facility workers (plumbers, landscapers, electricians) and 20 custodial workers. Our analysis revealed altered microbial composition and diversity according to phthalate urinary biomarker concentration within the two worker groups. Higher urinary biomarker concentrations of select phthalates (MBP, MBIP, and ∑DEHP) were associated with increased Moraxella relative abundance, which has been positively associated with asthma. Within-sample alpha diversity levels were decreased in facility workers and were generally inversely associated with most phthalate urinary biomarker concentrations. Our research suggests that exposure to chemicals in this vulnerable worker group may impact the respiratory microbiome, which may increase risk of development of adverse health conditions. Further research is warranted to refine the mechanistic pathways that underpin the relationships between phthalate exposures and respiratory microbial communities to provide key insights on respiratory pathologies and, most importantly, to identify modifiable risk factors that can be used to direct mitigation efforts aimed at ameliorating the harmful effects of chemical exposures in this understudied occupational population.