Air pollution and decreased bone mineral density among Women's Health Initiative participants

Seasonal Characterization of Primary and Secondary Sources of Fine PM-Bound Water-Soluble Organic Carbon in Central Los Angeles

Understanding the sources and formation processes of fine particulate matter (PM2.5) is crucial for improving urban air quality and public health. This study provides a real-time analysis of PM2.5-bound water-soluble organic carbon (WSOC) and related carbonaceous species during winter, spring, and summer periods in 2023-2024, aiming to identify their major sources in central Los Angeles. Using advanced online monitoring equipment, including a Sunset Laboratory EC/OC analyzer and a custom-developed setup including a total organic carbon (TOC) analyzer coupled with a particle collection system, we obtained hourly measurements of organic carbon (OC), its fractions (OC1-OC4, based on volatility), elemental carbon (EC), and WSOC. Positive matrix factorization (PMF) identified three principal PM2.5 sources: vehicular emissions, secondary organic carbon (SOC) formation influenced by nighttime aqueous-phase chemical processes, and SOC formation driven by daytime photochemical reactions. Vehicular emissions dominated EC levels, accounting for 86-95% across seasons. This factor also had high contributions from nitrogen oxides (NOₓ) (75-82%), vehicle counts (approximately 85%), and OC1 (51-83%), reflecting the persistent influence of traffic emissions. Nighttime SOC formation was significant in winter, with WSOC and OC4 contributing 58% and 40% to this factor. In contrast, daytime photochemical SOC formation was prominent in summer, with WSOC and OC4 contributing 63% and 47%, and ozone loading up to 89%, reflecting increased photochemical activity. Spring exhibited a mix of aqueous and photochemical SOC formation, with similar contributions from WSOC (38-35%) and OC4 (35-33%), reflecting the transitional season's mixed SOC formation mechanisms. Diurnal profiles revealed that primary emissions peaked during morning rush hours, while secondary formation processes elevated OC levels at night in winter and during afternoons in summer. The EC tracer method corroborated these findings by estimating primary and secondary organic carbon levels, highlighting significant seasonal and diurnal variations in carbonaceous aerosols. These results emphasize the need for targeted strategies addressing both primary emissions and the precursors of secondary aerosol formation, to improve air quality in Los Angeles.

The silent invasion of microplastics polyvinyl chloride and polyethylene terephthalate: Potential impact on osteoporosis

BACKGROUND

The relationship between the environment and diseases is a crucial and complex topic that has garnered significant attention in recent years. In our study, we also follow the thread and explore the correlation between microplastics (MPs) and osteoporosis (OP).

METHODS AND RESULTS

We found that MPs were detected in the blood samples of nearly all participants. Moreover, It was compelling that PVC and PET emerged as the most common MP polymers in our study. A verification process was conducted comparing the clinical data with the results of MPs detection. This analysis revealed a significant exposure risk to MPs from sources such as bottled water, take-out containers. Through molecular biology techniques, we confirmed that MPs have a significant toxic effect on osteoblasts and associated with abnormal gene expression.

CONCLUSION

MPs may be considered to have a potential correlation with the progression of OP.

Prenatal exposure to ozone and bone mineral density in early childhood: Susceptible window identification

BACKGROUND

The effect of prenatal ozone exposure on early childhood bone mineral density (BMD) remains to be explored.

METHODS

This study was based on the pediatric subcohort of the Fujian Birth Cohort Study. The mean ozone exposure concentration was calculated for the entire pregnancy, as well as for each trimester (first, second, and third) and for every gestational week. BMD was assessed using quantitative ultrasonography (QUS). Low BMD was defined as a z-score of less than -1. Linear and logistic regression models were used to assess the effect of maternal ozone exposure. Distributed lag models (DLMs) were applied to identify the sensitive windows of ozone exposure.

RESULTS

1345 mother-offspring pairs were included in this study. We found that for every interquartile range (IQR) increase in ozone levels of different exposure durations (entire pregnancy, first, second, and third trimester), BMD z-scores decreased by 0.12 (95 % CI: 0.18, -0.07), 0.07 (95 % CI: 0.11, -0.02), 0.08 (95 % CI: 0.14, -0.02), and 0.07 (95 % CI: 0.13, -0.01), respectively. For low BMD, an IQR increase in ozone levels was associated with 1.47 times higher odds of low BMD (95 % CI: 1.09, 1.98) in the second trimester. The most pronounced negative association with BMD z-scores was observed between the 9th and 16th gestational weeks. For low BMD, the highest OR was observed between the 15th and 17th gestational weeks.

CONCLUSIONS

Prenatal exposure to ozone was inversely associated with BMD in early childhood, with early to mid-pregnancy identified as the susceptible window.

Association between air pollution and osteoporosis: A Mendelian randomization study

Osteoporosis (OP) is a significant disease in the aging society, which poses a threat to the physical well-being of older adults. Some studies suggest that air pollution may contribute to an increased incidence of OP; however, this causal relationship has not been firmly established. To address this gap, we conducted Mendelian randomization (MR) analysis to assess the potential causal association between air pollution (including nitrogen dioxide [N = 456,380], nitrogen oxides [N = 456,380], particulate matter [PM]2.5 [N = 423,796], and PM10 [N = 455,314]) and total-body bone mineral density (BMD) (N = 56,284). We utilized summary data from IEU Open GWAS on the database of genome-wide association studies (GWAS) and employed inverse variance weighting (IVW) as our primary analytical approach. The findings from our MR study in the European population using the IVW method indicated a potential causal link between nitrogen oxides: β = -0.59, confidence interval (CI) = (-1.03 to -0.16), P = 0.008; PM2.5: β = -0.60, CI = (-1.12 to -0.08), P = .025. These results suggest that there might be a causative relationship between nitrogen oxides, PM2.5, and BMD with regards to OP development among individuals exposed to air pollution. Importantly, the observed associations passed all statistical tests without any evidence of heterogeneity or pleiotropy. Furthermore, the presence of air pollution was found to be associated with an elevated risk of developing OP. This study provides compelling evidence for a causal connection between nitrogen oxides, PM2.5, and OP, suggesting that reducing air pollution could play a crucial role in preventing OP development.

Bridging the gender, climate, and health gap: the road to COP29

Focusing specifically on the gender-climate-health nexus, this Personal View builds on existing feminist works and analyses to discuss why intersectional approaches to climate policy and inclusive representation in climate decision making are crucial for achieving just and equitable solutions to address the impacts of climate change on human health and societies. This Personal View highlights how women, girls, and gender-diverse people often face disproportionate climate-related health impacts, particularly those who experience compounding and overlapping vulnerabilities due to current and former systems of oppression. We summarise the insufficient meaningful inclusion of gender, health, and their intersection in international climate governance. Despite the tendency to conflate gender equality with number-based representation, climate governance under the UNFCCC (1995-2023) remains dominated by men, with several countries projected to take over a decade to achieve gender parity in their Party delegations. Advancing gender-responsiveness in climate policy and implementation and promoting equitable participation in climate governance will not only improve the inclusivity and effectiveness of national strategies, but will also build more resilient, equitable, and healthier societies.

Air Pollution and Osteoporosis

PURPOSE OF REVIEW

The purpose of this review is to provide a background of osteoporosis and air pollution, discussing increasing incidence of the disease with exposure to pollutants and the role that inflammation may play in this process.

RECENT FINDINGS

Osteoporosis-related fractures are one of the most pressing challenges for the ageing global population, with significant increases in mortality known to occur after major osteoporotic fractures in the elderly population. Recent studies have established a firm correlative link between areas of high air pollution and increased risk of osteoporosis, particularly alarming given the increasingly urban global population. While the culprit pollutants and molecular mechanisms underlying this phenomenon have not yet been elucidated, initial studies suggest a role for inflammatory cascades in this phenomenon. While much more research is required to identify the most damaging air pollutants and to delineate the specific inflammatory molecular mechanisms, it is clear from the literature that shedding light on these pathways would unveil potential therapeutic targets to treat bone diseases, including osteoporosis. Major deficiencies of current animal models highlight the need for complex human in vitro models such as organ-on-a-chip technology to better understand the impact of air pollution.

Exposure to air pollution might decrease bone mineral density and increase the prevalence of osteoporosis: a Mendelian randomization study

This study, using Mendelian randomization, reveals a causal link between nitrogen oxides and PM2.5 exposure and reduced total-body bone mineral density, highlighting a potential risk factor for osteoporosis. The findings emphasize the importance of targeted interventions in populations exposed to higher air pollution.

INTRODUCTION

With the aging of the population, the prevalence of osteoporosis is escalating. Observational studies suggest that air pollution might diminish bone mineral density (BMD), contributing to elevating the likelihood of developing osteoporosis.

METHODS

Employing a two-sample Mendelian randomization (MR) analysis, our study aimed to explore the potential causal effect of air pollution on total-body BMD. We utilized extensive publicly available data from genome-wide association studies (GWAS) in this research. Inverse variance weighting was selected for the primary effect estimation, complemented by additional approaches such as the weighted median, MR-Egger, simple mode, and weighted mode. Sensitivity analyses were then conducted to evaluate heterogeneity, pleiotropy, and the presence of outliers.

RESULTS

In the MR analysis, our findings revealed causal associations between nitrogen oxides (β =  - 0.55, 95% CI - 0.90 to - 0.21, P = 0.002) and particulate matter (PM) 2.5 (β =  - 0.33, 95% CI - 0.59 to - 0.08, P = 0.010) and a reduction in total-body BMD. No significant associations were detected between PM2.5-10, PM10, nitrogen dioxide, and total-body BMD (P > 0.05). Rigorous sensitivity analyses verified the stability of these significant results.

CONCLUSIONS

Our study illustrates that exposure to nitrogen oxides and PM2.5 may lead to a decrease in total-body BMD, increasing the risk of osteoporosis. This evidence holds crucial implications for policymakers and healthcare providers, as it can provide targeted interventions for the prevention of osteoporosis.

Disentangling the Relationship Between Urinary Metal Exposure and Osteoporosis Risk Across a Broad Population: A Comprehensive Supervised and Unsupervised Analysis

Background: Limited evidence links urinary metal exposure to osteoporosis in broad populations, prompting this study to cover this knowledge gap using supervised and unsupervised approaches. Methods: This study included 15,923 participants from the National Health and Nutrition Examination Survey (NHANES) spanning from 1999 to 2020. Urinary concentrations of nine metals-barium (Ba), cadmium (Cd), cobalt (Co), cesium (Cs), molybdenum (Mo), lead (Pb), antimony (Sb), thallium (Tl), and tungsten (Tu)-were measured using inductively coupled plasma mass spectrometry (ICP-MS). Osteoporosis was assessed via dual-energy X-ray absorptiometry. A weighted quantile sum (WQS) regression analysis evaluated each metal's contribution to osteoporosis risk. Partitioning around medoids (PAM) clustering identified the high- and low-exposure groups, and their association with the risk and prognosis of osteoporosis was evaluated. Results: WQS regression identified Cd as a significant osteoporosis risk factor in the general population (odds ratio (OR) = 1.19, 95% confidence interval (CI): 1.08, 1.31, weight = 0.66). Pb notably affected those individuals aged 30-49 years and classified as Mexican American, while Sb impacted Black individuals. PAM clustering showed that the high-exposure group had a significantly higher risk of osteoporosis (OR = 1.74, 95% CI: 1.43, 2.12) and cumulative mortality risk. Conclusions: Urinary metals are associated with the risk and prognosis of osteoporosis.

Targeting the mTOR-Autophagy Axis: Unveiling Therapeutic Potentials in Osteoporosis

Osteoporosis (OP) is a widespread age-related disorder marked by decreased bone density and increased fracture risk, presenting a significant public health challenge. Central to the development and progression of OP is the dysregulation of the mechanistic target of the rapamycin (mTOR)-signaling pathway, which plays a critical role in cellular processes including autophagy, growth, and proliferation. The mTOR-autophagy axis is emerging as a promising therapeutic target due to its regulatory capacity in bone metabolism and homeostasis. This review aims to (1) elucidate the role of mTOR signaling in bone metabolism and its dysregulation in OP, (2) explore the interplay between mTOR and autophagy in the context of bone cell activity, and (3) assess the therapeutic potential of targeting the mTOR pathway with modulators as innovative strategies for OP treatment. By examining the interactions among autophagy, mTOR, and OP, including insights from various types of OP and the impact on different bone cells, this review underscores the complexity of mTOR's role in bone health. Despite advances, significant gaps remain in understanding the detailed mechanisms of mTOR's effects on autophagy and bone cell function, highlighting the need for comprehensive clinical trials to establish the efficacy and safety of mTOR inhibitors in OP management. Future research directions include clarifying mTOR's molecular interactions with bone metabolism and investigating the combined benefits of mTOR modulation with other therapeutic approaches. Addressing these challenges is crucial for developing more effective treatments and improving outcomes for individuals with OP, thereby unveiling the therapeutic potentials of targeting the mTOR-autophagy axis in this prevalent disease.

Identification of endocrine-disrupting chemicals targeting key OP-associated genes via bioinformatics and machine learning

Osteoporosis (OP), a metabolic disorder predominantly impacting postmenopausal women, has seen considerable progress in diagnosis and treatment over the past few decades. However, the intricate interplay between genetic factors and endocrine disruptors (EDCs) in the pathogenesis of OP remains inadequately elucidated. The objective of this research is to examine the environmental pollutants and their regulatory mechanisms that could potentially influence the pathogenesis of OP, in order to establish a theoretical foundation for the targeted prevention and medical management of individuals with OP. Utilizing CTD and GEO datasets, network toxicology and bioinformatics analyses were conducted to identify target genes from a pool of 98 co-associated genes. Subsequently, a novel prediction model was developed employing a multiple machine learning algorithm. The efficacy of the model was validated based on the area under the receiver operating characteristic curve. Finally, real-time quantitative polymerase chain reaction (qRT-PCR) was used to confirm the expression levels of key genes in clinical samples. We have identified significant genes (FOXO3 and LUM) associated with OP and conducted Gene Ontology, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, immune infiltration analysis, and molecular docking analysis. Through the analysis of these key genes, we have identified 13 EDCs that have the potential to impact OP. Several endocrine disruptors, such as Dexamethasone, Perfluorononanoic acid, genistein, cadmium, and bisphenol A, have been identified as notable environmental pollutants that impact the OP. Molecular docking analysis revealed significant binding affinity of major EDCs to the post-translational protein structures of key genes. This study demonstrates that EDCs, including dexamethasone, perfluorononanoic acid, genistein, cadmium, and bisphenol A, can be identified as important environmental pollutants affecting OP, and that FOXO3 and LUM have the potential to be diagnostic markers for OP. These results elucidate a novel association between EDCs regulated by key genes and the onset of OP.

Prevalence Characteristics of Osteoporosis Fractures in the Elderly in Two Regions of China and Analysis of the Lag Effect of Air Pollutants on them

OBJECTIVE

Air pollution is increasing and threatening human health. The objective of this study is to investigate the population distribution characteristics of elderly osteoporosis fractures in Hebei Province and Xinjiang Uygur Autonomous Region and to analyze the effects of air pollutants on the number of elderly osteoporosis fracture inpatients in the two regions.

METHOD

A retrospective collection of elderly osteoporosis fracture cases was conducted in selected hospitals in Hebei Province and Xinjiang Uygur Autonomous Region from January 1, 2018 to December 31, 2022. The chi-square test was used to compare the distributional characteristics of the population in the two regions. Additionally, we used a distributed lag nonlinear model (DLNM) in order to assess the effect of air pollutants on the number of daily hospital admissions of elderly osteoporosis fracture patients in different regions.

RESULT

A total of 19,203 elderly osteoporosis fracture patients were included in the study. The average age of these patients was 76.66 ± 7.55 years, and the majority of them were female (13,514 instances, 70.37%). The disparities in age distribution (χ2 = 133.9 p < 0.001), fracture site (χ2 = 62.0 p < 0.001), and hospitalization cost (Z = -15.635 p < 0.001) between the two regions were statistically significant. The lag effect curves of PM2.5, PM10, and NO2 on the number of elderly osteoporosis fracture hospitalizations in Xinjiang Uygur Autonomous Region exhibited a similar pattern resembling a "W"-shaped curve. All three pollutants reached their highest values after a lag time of 14 days (PM2.5: RR = 1.053, 95% CI: 1.031, 1.074; PM10: RR = 1.031, 95% CI: 1.018, 1.043; NO2: RR = 1.125, 95% CI: 1.070, 1.182). In Hebei Province, the largest impacts of PM2.5 and PM10 were observed after a lag of 14 days (PM2.5: RR = 1.022, 95% CI: 1.013, 1.028; PM10: RR = 1.013, 95% CI: 1.008, 1.018). Similarly, the maximum effect of NO2 was observed after a lag of 11 days (RR = 1.020, 95% CI: 1.010, 1.028).

CONCLUSION

There were differences in the epidemiological characteristics of hospitalized patients with osteoporosis fractures between the two regions, PM2.5, PM10, and NO2 increased the number of hospitalizations for osteoporosis fractures. Exposure to air pollutants such as PM2.5 increases the risk of osteoporosis fractures in the elderly population.

Assessment of short-term effects of ambient air pollution exposure on osteoarthritis outpatient visits

The association of short-term ambient air pollution exposure with osteoarthritis (OA) outpatient visits has been unclear and no study has assessed the modifying roles of district-level characteristics in the association between ambient air pollution exposure and OA outpatient visits. We investigated the cumulative associations of ambient air pollution exposure with daily OA outpatient visits and vulnerable factors influencing the associations using data from 16 districts of Beijing, China during 2013-2019. A total of 18,351,795 OA outpatient visits were included in the analyses. An increase of 10 μg/m3 in fine particulate matter (PM2.5), inhalable particulate matter (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), maximum 8-hour moving-average ozone (8 h-O3), and 0.1 mg/m3 in carbon monoxide (CO) at representative lag days were associated with significant increases of 0.31 %, 0.06 %, 0.77 %, 0.87 %, 0.30 %, and 0.48 % in daily OA outpatient visits, respectively. Considerable OA outpatient visits were attributable to short-term ambient air pollution exposure. In addition, low temperature and high humidity aggravated ambient air pollution associated OA outpatient visits. District-level characteristics, such as population density, green coverage rate, and urbanization rate modified the risk of OA outpatient visits associated with air pollution exposure. These findings highlight the significance of controlling ambient air pollution during the urbanization process, which is useful in policy formation and implementation.

Causal Relationships between Air Pollutant Exposure and Bone Mineral Density and the Risk of Bone Fractures: Evidence from a Two-Stage Mendelian Randomization Analysis

A number of studies from the literature have suggested that exposure to air pollutants is associated with a declined bone mineral density (BMD), and increased risks of osteoporosis (OP) and bone fractures. This study was performed to systemically assess the genetically causal associations of air pollutants with site-/age-specific BMD and risk of bone fractures with the implementation of two-sample Mendelian randomization (TSMR) and multivariate Mendelian randomization (MVMR). The TSMR analysis was implemented to infer the causal associations between air pollutants and BMD and the risk of bone fractures, additional MVMR analysis was used to further estimate the direct causal effects between air pollutants and BMD, the occurrence of OP, and bone fractures. The results showed that NOx exposure contributed to lower femoral neck BMD (FN-BMD) (β = -0.71, 95%CI: -1.22, -0.20, p = 0.006) and total body BMD (TB-BMD) (β = -0.55, 95%CI: -0.90, -0.21, p = 0.002). Additionally, exposure to PM10 was found to be associated with a decreased TB-BMD (B β = -0.42, 95%CI: -0.66, -0.18, p = 0.001), further age-specific subgroup analysis demonstrated the causal effect of PM10 exposure on the decreased TB-BMD in a subgroup aged 45 to 60 years (β = -0.70, 95%CI: -1.12, -0.29, p = 0.001). Moreover, the findings of the MVMR analysis implied that there was a direct causal effect between PM10 exposure and the decreased TB-BMD (45 < age < 60), after adjusting for PM2.5 and PM2.5 -10 exposure. Our study provides additional evidence to support the causal associations of higher concentrations of air pollutant exposure with decreased BMD, especially in those populations aged between 45 to 60 years, suggesting that early intervention measures and public policy should be considered to improve public health awareness and promote bone health.

Global Health Disparities in Childhood Rickets

Nutritional rickets is a global health problem reflecting both historical and contemporary health disparities arising from racial, ethnic, environmental, and geopolitical circumstances. It primarily affects marginalized populations and can contribute to long-term morbidity. Deficits in bone health in childhood may also contribute to osteomalacia/osteoporosis. Solutions require a global public health approach.

Impact of climate and environmental change on the menopause

The huge impact of climate change on humankind is multidimensional, and includes direct and indirect challenges to the physical, psychological and socio-cultural wellbeing. Women may be more vulnerable to climate-sensitive diseases, but little attention has been paid to specific needs and challenges associated with the menopause transition. The increase in average and extreme temperatures may modulate the manifestation of vasomotor symptoms; in particular, environmental temperature and seasonality may affect hot flushes and night sweats. However, more research is needed to define the impact of climate-related factors among the determinants influencing the individual experience of menopause. In addition, increased exposure to environmental pollution and toxins may also have a role in the modulation of ovarian aging mechanisms, possibly influencing timing of menopause. Finally, both air pollution and menopause transition are associated with unfavorable modifications of cardio-metabolic, bone and cognitive health, and account should be taken of these in the evaluation of the individual woman's health vulnerabilities. Overall, the evidence reported in this narrative review supports the need for specific strategies aimed at reducing the burden of climate and environmental change on menopausal women. Healthcare providers should promote behavioral measures that reduce anthropogenic climate change and at the same time have a beneficial role on several domains of physical and psychological wellbeing. From this perspective, menopause represents a golden moment to implement virtuous behaviors that will benefit at the same time women's longevity and the planet.

Exposure to Multiple Air Pollutants and the Risk of Fractures: A Large Prospective Population-Based Study

Atmospheric chemistry studies suggest air pollution impedes ultraviolet B photons and thus reduces cutaneous vitamin D3 synthesis. Biological evidence shows that inhaled pollutants disrupt circulating 25-hydroxyvitamin D (25[OH]D) metabolism and ultimately impact bone health. The hypothesis is that higher air pollution concentrations are associated with a higher risk of fractures, mediated by lower circulating 25(OH)D. The study included participants of the UK Biobank who were free of fracture history at enrollment (2006 to 2010) and analyzed their environmental exposure data (2007 to 2010). Air pollution measurements included the annual averages of air particulate matter (PM2.5 , PM2.5-10 , and PM10 ), nitrogen oxides (NO2 and NOx ), and a composite air pollution score. Multivariable Cox proportional hazard models were used to assess the associations of the individual pollutants and the score with fracture risks. Mediation analyses were conducted to assess the underlying role of serum 25(OH)D in such associations. Among 446,395 participants with a median of 8-year follow-up, 12,288 incident fractures were documented. Participants living in places with the highest quintile of air pollution score had a 15.3% increased risk of fractures (hazard ratio [95%CI]: 1.15[1.09,1.22]) compared to those in the lowest, and 5.49% of this association was mediated through serum 25(OH)D (pmediation  < 0.05). Pollutant-specific hazard of top-to-bottom quintiles was 16% for PM2.5 , 4% for PM2.5-10 , 5% for PM10 , 20% for NO2 , and 17% for NOx , with a 4% to 6% mediation effect of serum 25(OH)D concentrations. The associations of the air pollution score with fracture risks were weaker among female participants, those who drank less alcohol, and consumed more fresh fruit than their counterparts (pinteraction  < 0.05). © 2023 American Society for Bone and Mineral Research (ASBMR).