Air pollution exposure and auto-inflammatory and autoimmune diseases of the musculoskeletal system: a review of epidemiologic and mechanistic evidence

Association of ambient air pollution with hospital admissions for major osteoarthritis diseases: A national case-crossover study in China

OBJECTIVES

To investigate the acute effects of short-term exposure to ambient air pollution on the risk of hospital admissions for osteoarthritis (OA) and its major subtypes.

METHODS

Hospital admission data on OA and its major subtypes were sourced from two major urban medical insurance systems in China, covering the period from 2013 to 2017. A two-stage, time-stratified case-crossover design was used to investigate the acute effects of short-term exposure to ambient air pollutants on hospital admissions for OA across 278 Chinese cities with available hospital admission data over 50 cases. The conditional logistic regression model was utilized to assess city-specific associations, which were subsequently pooled by employing a random-effects model.

RESULTS

A total of 1,404,095 OA-related hospital admissions were included. At the main time windows, per interquartile range increases in PM2.5 (particulate matter with an aerodynamic diameter of ≤ 2.5 μm), PM10 (particulate matter with an aerodynamic diameter of ≤ 10 μm), NO2 (nitrogen dioxide), SO2 (sulfur dioxide), O3 (ozone), and CO (carbon monoxide) were associated with significant increases in OA-related admissions by 0.70 % (95 % CI: 0.12 %, 1.28 %), 1.08 % (95 % CI: 0.47 %, 1.69 %), 4.50 % (95 % CI: 3.36 %, 5.65 %), 2.75 % (95 % CI: 1.79 %, 3.72 %), 1.33 % (95 % CI: 0.57 %, 2.10 %) and 1.77 % (95 % CI: 0.76 %, 2.79 %), respectively. Short-term exposures to ambient air pollutants were also associated with increased hospital admissions for major OA subtypes, especially gonarthrosis. The attributable fractions of OA admissions ranged from 0.87 % for PM2.5 to 6.22 % for NO2.

CONCLUSIONS

Short-term exposure to ambient air pollution is significantly associated with an increased risk and burden of OA admissions.

A decade of exposure: Long-term air pollution and its impact on osteoarthritis: A nationwide cohort study in Taiwan

OBJECTIVE

To investigate the association between long-term exposure to ambient air pollution and the risk of developing osteoarthritis (OA) in a large nationwide cohort in Taiwan.

DESIGN

We conducted a retrospective cohort study using data from Taiwan's National Health Insurance Research Database linked with air pollution monitoring records from 76 environmental stations between 1993 and 2013. A total of 526,630 adults with complete 10-year cumulative exposure data were followed from the end of the exposure window until OA diagnosis, death, or study end. Cox proportional hazards models were applied to estimate hazard ratios (HRs) per standard deviation (SD) increase in pollutant exposure, adjusting for demographic, socioeconomic, and clinical confounders. Pollutants that satisfied the proportional hazards assumption (carbon monoxide [CO], particles less than 10 μm in diameter [PM₁₀], and nitrogen dioxide [NO2]) were included in the final analysis to ensure model validity.

RESULTS

During follow-up, 58,369 incident OA cases were identified (11.08% incidence). A 1 SD increase in CO, PM₁₀, and NO₂ exposure was associated with HRs of 1.83 (95% confidence interval: 1.81-1.84), 1.58 (1.56-1.60), and 1.62 (1.61-1.64), respectively (all p < 0.001). These associations were robust across sex subgroups and exhibited consistent dose-response relationships.

CONCLUSIONS

We observed a significant association between prolonged exposure to CO, PM₁₀, and NO₂ and increased OA risk. These findings support air pollution as a modifiable risk factor for OA and highlight the importance of environmental health interventions in disease prevention strategies.

Long-term air pollution exposure and cardiovascular disease progression in rheumatoid arthritis: A prospective cohort study using multi-state model analysis

BACKGROUND

Patients with rheumatoid arthritis (RA) have a significantly elevated risk of developing cardiovascular disease (CVD), the leading cause of their death. However, the impact of environmental factors on RA progression remains unclear. This study aimed to explore the link between long-term air pollution exposure and the multi-stage progression from a healthy status to RA onset, then CVD development, and finally death.

METHODS

Utilizing data from 326,059 participants in the UK Biobank, we used a unidirectional multi-state Markov proportional hazards model to analyze the associations between long-term exposure to air pollutants (PM2.5, PM10, NO2, and NOx) and disease progression. The models included transitions from baseline healthy state to RA onset, to subsequent CVD, and to death. Air pollution exposure was assessed using land use regression models, and hazard ratios (HRs) were calculated per interquartile range (IQR) increase in pollutant concentrations.

RESULTS

During a median follow-up of 12.69 years, 3422 participants developed RA, of whom 424 subsequently developed CVD. PM2.5 and NO2 showed the most extensive effects across transition stages. Per IQR increase in PM2.5 was associated with increased risks of RA onset (HR: 1.08; 95 %CI: 1.03, 1.12) and RA to death (HR: 1.20; 95 %CI: 1.06, 1.37), while NO2 was associated with increased risks of RA onset (HR: 1.10; 95 %CI: 1.06, 1.15) and subsequent CVD development (HR: 1.13; 95 %CI: 1.01, 1.28). Notably, valve disorders showed associations with multiple pollutants, and these effects were more pronounced in women and elderly participants.

CONCLUSION

Long-term exposure to air pollutants was significantly associated with increased risks at multiple transition stages, from RA onset to subsequent CVD development and death, although effect sizes were modest for some transitions. Considering the widespread global exposure to air pollution, these findings emphasize the importance of air pollution control in preventing RA and its cardiovascular complications, especially among susceptible populations.

Air pollution and systemic immune biomarkers in early life: A systematic review

INTRODUCTION

Children's rapid development and immature immune systems place them at a higher risk of adverse health outcomes associated with air pollution exposure. However, the specific mechanisms in which air pollution mediates immune dysregulation in youth are poorly understood. Thus, we aimed to systematically review the available epidemiological evidence surrounding the effects of indoor and ambient air pollution exposure on systemic immune biomarkers in early life (from birth to 18 years old).

METHODS

based on PRISMA guidelines, we developed a systematic search strategy and defined inclusion and exclusion criteria to retrieve publications from PubMed, SCOPUS and Web of Science published up to August 10th, 2024. Quality assessment and evidence evaluation were also performed. Five independent reviewers participated in the process.

RESULTS

In total, 96 studies were included. We found limited evidence of a causal relationship between prenatal ambient PM2.5 and reduced T-cells (CD3+ and CD8+), as well as between postnatal PM exposure and increased IgE levels or allergic sensitization. For the rest of exposure-outcome combinations we classified the evidence as inadequate, mainly due to the limited number of studies available or the lack of consistency in the results obtained among them. This was particularly the case for indoor air pollution research, for which only 12 studies were available.

CONCLUSION

the present systematic review highlights the need for further research on the impacts of air pollution on youth's immune system. We provided recommendations for future studies in order to better understand the early subclinical and clinical effects of air pollution and the underlying biological pathways, and identify the dynamics of the innate and adaptive immune responses to environmental threats. Considering the significance of childhood immunity on health outcomes within all stages of life, and the globally extensive burden of air pollution exposure, further research on this topic should be prioritized.

Trend analysis and cross-national inequity analysis of immune-mediated inflammatory diseases in children and adolescents aged 10-24 from 1990 to 2021

Introduction

Immune-mediated inflammatory diseases (IMIDs) are chronic inflammatory diseases caused by immune system dysregulation, affecting multiple systems and organs. Children and adolescents aged 10-24 are among the high-risk groups, and the global burden is substantial.

Methods

Using the latest data from global burden of disease (GBD) 2021, we employed Joinpoint regression analysis, Socio-Demographic Index (SDI) correlation analysis, and cross-national equity analysis to elucidate the spatiotemporal differences in the burden of IMIDs among 10-24-year-olds from 1990 to 2021.

Results

The burden of IMIDs in adolescents aged 10-24, ranked by severity, includes asthma, atopic dermatitis (AD), psoriasis, diabetes, rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and multiple sclerosis (MS). Among these, asthma, AD, psoriasis, RA, and MS are more prevalent in females. Compared to 1990, the incidence rates of asthma and AD decreased in 2021, while the rates of psoriasis, diabetes, and RA increased. IMIDs are more common in Western Europe and North America, with rising incidence rates in South America and Asia. Concentration indices and slope indices indicate that these diseases are primarily concentrated in high SDI regions, although the differences in incidence rates between countries are decreasing.

Conclusion

While focusing on high-incidence regions, we must also pay attention to the incidence of IMIDs in emerging regions such as Asia and South America. Only in this way can we effectively reduce the heavy burden that IMIDs place on younger people globally.

Association of fine particulate matter and residential green space with rheumatoid arthritis

BACKGROUND

Fine particulate matter (PM2.5) is a recognized risk factor for respiratory and cardiovascular diseases, but the association between PM2.5 and rheumatoid arthritis (RA) is still controversial. Additionally, evidence on the relationship of green space with RA is scarce. This study aimed to investigate the separate and combined associations of PM2.5 and green space with risk of RA.

METHODS

Our study involved 30,684 participants from the Yinzhou cohort in Ningbo, China. PM2.5 concentrations were determined using a land-use regression model. Residential green space was assessed using the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) from satellite images. We employed the Cox proportional hazard model to evaluate the relationships of PM2.5 and green space with RA.

RESULTS

During the 176,894 person-years of follow-up period, 354 cases of RA were identified. Hazard ratio (HR) and the corresponding 95% confidence interval (95% CI) for every interquartile range (IQR) increase in PM2.5 were 1.23 (95% CI: 1.02, 1.49). Compared with lower exposure to residential green space, individuals living in areas with more green space had a decreased risk of RA (HR was 0.80 (95% CI: 0.70, 0.92), 0.80 (95% CI: 0.70, 0.92), and 0.79 (95% CI: 0.70, 0.89) for 250m, 500m, and 1000m NDVI buffers, respectively). Similar results were observed for the association between EVI and RA. Furthermore, a significant multiplicative interaction was observed between PM2.5 and green space (NDVI 250m and EVI 250m). No mediating effect of PM2.5 on the relationship between green space and RA was observed.

CONCLUSION

Our findings indicated that living in areas with higher green space was linked to a reduced risk of RA, whereas living in areas with higher PM2.5 was associated with an increased risk of RA. The beneficial effect of high green space may be offset by exposure to PM2.5.

Airborne culprits: A comprehensive review of PM, silica, and TCDD in autoimmune diseases

Autoimmune diseases (ADs) are immunological disorders arising from the breakdown of immune tolerance, influenced by various internal and external factors. Persistent exposure to environmental factors, particularly air pollution, is linked to systemic inflammation, oxidative stress, and apoptosis, which contribute to the development of ADs. This review examines the impact of air pollutants, including particulate matter, silica, and TCDD, by analyzing epidemiological studies, animal models, and in vitro assays. It focuses on how air pollution disrupts the immune system, leading to apoptosis, increased oxidative stress, cytokine production, autoantigen release, autoantibody production, and autoreactivity, which are particularly significant in ADs like rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, and systemic sclerosis. In essence, this approach aims to provide a profound understanding of how exposure to air pollution can initiate or contribute to ADs, offering potential avenues for more targeted preventive and therapeutic strategies.

Unraveling Cross-Organ Impacts of Airborne Pollutants: A Multiomics Study on Respiratory Exposure and Gastrointestinal Health

Poor air quality is increasingly linked to gastrointestinal diseases, suggesting a potential correlation with human intestine health. However, this relationship remains largely unexplored due to limited research. This study used a controlled mouse model exposed to cooking oil fumes (COFs) and metagenomics, transcriptomics, and metabolomics to elucidate interactions between intestine microbiota and host metabolism under environmental stress. Our findings reveal that short-term COF inhalation induces pulmonary inflammation within 3 days and leads to gastrointestinal disturbances, elucidating a pathway connecting respiratory exposure to intestinal dysfunction. The exposure intensity significantly correlates with changes in intestinal tissue integrity, microbial composition, and metabolic function. Extended exposure of 7 days disrupts intestine microbiota and alters tryptophan metabolism, with further changes observed after 14 days, highlighting an adaptive response. These results highlight the vulnerability of intestinal health to airborne pollutants and suggest a pathway through which inhaled pollutants may affect distant organ systems.

Exposure to air pollutants and rheumatoid arthritis biomarkers: A scoping review

INTRODUCTION

Rheumatoid arthritis (RA) is a common autoimmune disease with a complex and poorly understood etiology that includes genetic, hormonal, and environmental factors.

OBJECTIVE

Our objective was to assess current literature that investigated the association between exposure to environmental and occupational air pollutants and RA-related biomarkers rheumatoid factor (RF) and anti-citrullinated peptide antibody (ACPA).

DESIGN

PubMed and Web of Science were used to identify epidemiological studies that measured or estimated air pollution and at least one RA biomarker. Information was charted for comparison of evidence, including pollutant(s) studied, exposure assessment, biomarker measurement, analysis method, study population, size, dates, adjustment variables, and findings.

RESULTS

Several common air pollutants (including two mixtures) and a few dozen occupational inhalants were assessed in 13 eligible studies. Associations between industrial sulfur dioxide and particulate matter less than 2.5 µm in diameter with ACPA were observed most frequently, including associations between residential proximity to pollution sources and ACPA positivity. Consistency of associations with other pollutants was either not observed or limited to single studies. Three studies evaluated the modifying impact of SE alleles (a genetic factor associated with RA) and found that pollutant associations were stronger among participants positive for SE alleles.

CONCLUSION

Based on mixed results, there was no consistent link between any single pollutant and RA-related biomarker outcomes. Comparisons across studies were limited by differences in study populations (e.g., by RA status, by sociodemographic groups) and study design (including designs focused on different sources of air pollution, methodological approaches with varying levels of potential exposure misclassification, and assessments of inconsistent biomarker cut-points). However, given that multiple studies reported associations between exposure to air pollution and RA biomarkers, continued exploration utilizing studies that can be designed with a more robust causal framework, including continued consideration of effect modification by genetic status, may be necessary.

The impact of air pollutants on spontaneous abortion: a case-control study in Tongchuan City

OBJECTIVES

Studies related to air pollutants and spontaneous abortion in urban northwestern China are scarce, and the main exposure windows of pollutants acting on pregnant women are unclear.

STUDY DESIGN

Case-control study.

METHODS

Data were collected from pregnant women in Tongchuan City from 2018 to 2019. A total of 289 cases of spontaneous abortion and 1156 cases of full-term labor were included and analyzed using a case-control study. Logistic regression models were developed to explore the relationship between air pollutants and spontaneous abortion after Chi square analysis and Air pollutant description.

RESULTS

O3 (odds ratio [OR] = 1.028) is a risk factor for spontaneous abortion throughout pregnancy. PM2.5 (OR = 1.015), PM10 (OR = 1.010), SO2 (OR = 1.026), and NO2 (OR = 1.028) are risk factors for spontaneous abortion in the 30 days before the last menstrual period. PM2.5 (OR = 1.015), PM10 (OR = 1.013), SO2 (OR = 1.036), and NO2 (OR = 1.033) are risk factors for spontaneous abortion in the 30-60 days before the last menstrual period. PM2.5 (OR = 1.028), PM10 (OR = 1.013), SO2 (OR = 1.035), and NO2 (OR = 1.059) are risk factors for spontaneous abortion in the 60-90 days before the last menstrual period.

CONCLUSION

Exposure to high levels of air pollutants may be a cause of increased risk of spontaneous abortion, especially in the first trimester of the last menstrual period.

Global, regional and national temporal trends in prevalence for musculoskeletal disorders in women of childbearing age, 1990-2019: an age-period-cohort analysis based on the Global Burden of Disease Study 2019

OBJECTIVES

To provide an overview and in-depth analysis of temporal trends in prevalence of musculoskeletal (MSK) disorders in women of childbearing age (WCBA) at global, regional and national levels over the last 30 years, with a special focus on their associations with age, period and birth cohort.

METHODS

Estimates and 95% uncertainty intervals (UIs) for MSK disorders prevalence in WCBA were extracted from the Global Burden of Diseases, Injuries and Risk Factors Study 2019. An age-period-cohort model was adopted to estimate the overall annual percentage change of prevalence (net drift, % per year), annual percentage change of prevalence within each age group (local drift, % per year), fitted longitudinal age-specific rates adjusted for period deviations (age effects) and period/cohort relative risks (period/cohort effects) from 1990 to 2019.

RESULTS

In 2019, the global number of MSK disorders prevalence in WCBA was 354.57 million (95% UI: 322.64 to 387.68). Fifty countries had at least one million prevalence, with India, China, the USA, Indonesia and Brazil being the highest accounting for 51.03% of global prevalence. From 1990 to 2019, a global net drift of MSK disorders prevalence in WCBA was -0.06% (95% CI: -0.07% to -0.05%) per year, ranging from -0.09% (95% CI: -0.10% to -0.07%) in low-middle sociodemographic index (SDI) region to 0.10% (95% CI: 0.08% to 0.12%) in high-middle SDI region, with 138 countries presenting increasing trends, 24 presenting decreasing trends and 42 presenting relatively flat trends. As reflected by local drift, higher SDI regions had more age groups showing rising prevalence whereas lower SDI regions had more declining prevalence. Globally, an increasing occurrence of MSK disorders prevalence in WCBA beyond adolescent and towards the adult stage has been prominent. Age effects illustrated similar patterns across different SDI regions, with risk increasing with age. High SDI region showed generally lower period risks over time, whereas others showed more unfavourable period risks. High, high-middle and middle SDI regions presented unfavourable prevalence deteriorations, whereas others presented favourable prevalence improvements in successively birth cohorts.

CONCLUSIONS

Although a favourable overall temporal trend (net drift) of MSK disorders prevalence in WCBA was observed over the last 30 years globally, there were 138 countries showing unfavourable rising trends, coupled with deteriorations in period/cohort risks in many countries, collectively raising concerns about timely realisation of the Targets of Sustainable Development Goal. Improvements in the MSK disorders-related prevention, management and treatment programmes in WCBA could decline the relative risk for successively younger birth cohorts and for all age groups over period progressing.

Dysregulation of immunity by cigarette smoking promotes inflammation and cancer: A review

Smoking is a serious global health issue. Cigarette smoking contains over 7000 different chemicals. The main harmful components include nicotine, acrolein, aromatic hydrocarbons and heavy metals, which play the key role for cigarette-induced inflammation and carcinogenesis. Growing evidences show that cigarette smoking and its components exert a remarkable impact on regulation of immunity and dysregulated immunity promotes inflammation and cancer. Therefore, this comprehensive and up-to-date review covers four interrelated topics, including cigarette smoking, inflammation, cancer and immune system. The known harmful chemicals from cigarette smoking were summarized. Importantly, we discussed in depth the impact of cigarette smoking on the formation of inflammatory or tumor microenvironment, primarily by affecting immune effector cells, such as macrophages, neutrophils, and T lymphocytes. Furthermore, the main molecular mechanisms by which cigarette smoking induces inflammation and cancer, including changes in epigenetics, DNA damage and others were further summarized. This article will contribute to a better understanding of the impact of cigarette smoking on inducing inflammation and cancer.

Impact of short-term exposure to ambient air pollution on osteoarthritis: a multi-city time-series analysis in Central-Eastern China

Osteoarthritis (OA) is a threat to public health issue with high morbidity and disability worldwide. However, unequivocal evidence on the link between air pollution and OA remains little, especially in multi-study sites. This study aimed to explore the relationship between short-term exposure to main air pollutants and the risk of OA outpatient visits in multi-study sites. A multi-city time-series analysis was performed in Anhui Province, Central-Eastern China from January 1, 2015, to December 31, 2020. We used a two-stage analysis to assess the association between air pollution and daily OA outpatient visits. City-specific associations were estimated with a distributed lag nonlinear model and then pooled by random-effects or fixed-effects meta-analysis. Stratified analysis was conducted by gender, age, and season. Additionally, the disease burden of OA attributable to air pollutant exposure was calculated. A total of 35,700 OA outpatients were included during the study period. The pooled exposure-response curves showed that PM2.5 and PM10 concentrations below the reference values could increase the risk of OA outpatient visits. Concretely, per 10 ug/m3 increase in PM2.5 concentration was linked to an elevated risk of OA outpatient visits at lag 2 and lag 3 days, where the effect reached its highest value on lag 2 day (RR: 1.023, 95%CI: 1.005-1.041). We observed that a 10 μg/m3 increase in PM10 was positively correlated with OA outpatient visits (lag2 day, RR: 1.011, 95%CI: 1.001-1.025). Nevertheless, no statistical significance was discovered in gaseous pollutants (including SO2, O3, and CO). Additionally, a significant difference was found between cold and warm seasons, but not between different genders or age groups. This study reveals that particulate matter is an important factor for the onset of OA in Anhui Province, China. However, there is no evidence of a relationship of gaseous pollutants with OA in this area.

Emerging roles of air pollution and meteorological factors in autoimmune eye diseases

Autoimmune eye diseases (AEDs), a collection of autoimmune inflammatory ocular conditions resulting from the dysregulation of immune system at the ocular level, can target both intraocular and periorbital structures leading to severe visual deficit and blindness globally. The roles of air pollution and meteorological factors in the initiation and progression of AEDs have been increasingly attractive, among which the systemic and local mechanisms are both involved in. Exposure to excessive air pollution and extreme meteorological conditions including PM2.5/PM0.1, environmental tobacco smoke, insufficient sunshine, and high temperature, etc., can disturb Th17/Treg balance, regulate macrophage polarization, activate neutrophils, induce systemic inflammation and oxidative stress, decrease retinal blood flow, promote tissue fibrosis, activate sympathetic nervous system, adversely affect nutrients synthetization, as well as induce heat stress, therefore may together deteriorate AEDs. The crosstalk among inflammation, oxidative stress and dysregulated immune system appeared to be prominent. In the present review, we will concern and summarize the potential mechanisms underlying linkages of air pollution and meteorological factors to ocular autoimmune and inflammatory responses. Moreover, we concentrate on the specific roles of air pollutants and meteorological factors in several major AEDs including uveitis, Graves' ophthalmopathy (GO), ocular allergic disease (OAD), glaucoma, diabetic retinopathy (DR), etc.