Living near a freeway is associated with lower bone mineral density among Mexican Americans

Potential causal associations of PM2.5 and osteoporosis: a two-sample mendelian randomization study

Background: Observational studies suggest a potential association between atmospheric particulate matter 2.5 (PM2.5) and osteoporosis, but a causal association is unclear due to the presence of confounding factors. Methods: We utilized bone mineral density indices at four specific sites to represent osteoporosis: femoral neck (FN-BMD), lumbar spine (LS-BMD), forearm (FA-BMD), and heel (HE-BMD). The PM2.5 data was obtained from the UK Biobank database, while the datasets for FN-BMD, LS-BMD, and FA-BMD were obtained from the GEFOS database, and the dataset for HE-BMD was obtained from the EBI database. A two-sample Mendelian randomization analysis was conducted using mainly the inverse variance weighted method, horizontal pleiotropy and heterogeneity were also assessed. Results: The results indicated that PM2.5 was not correlated with a decrease in FN-BMD (β: -0.305, 95%CI: -0.762, 0.153), LS-BMD (β: 0.134, 95%CI: -0.396, 0.666), FA-BMD (β: -0.056, 95%CI: -1.172,1.060), and HE-BMD (β: -0.084, 95%CI: -0.261,0.093). Additionally, acceptable levels of horizontal pleiotropy and heterogeneity were observed. Conclusion: In contrast to most observational studies, our research did not discover a potential causal relationship between PM2.5 and the development of osteoporosis.

Tumor necrosis factor mediates the impact of PM2.5 on bone mineral density: Inflammatory proteome Mendelian randomization and colocalization analyses

To assess the causal effect of particulate matter 2.5 (PM2.5) on human bone mineral density (BMD) and to explore the possible mechanism and proportion mediated by inflammation-related protein. The genetic correlation between PM2.5 and BMD was assessed using the Linkage Disequilibrium Score (LDSC), and the causal effect between PM2.5 and BMD was assessed by two-sample Mendelian randomization (TSMR). A 2-step Mendelian randomization (MR) approach was employed to evaluate the potential role of inflammation-associated protein as the mediator in the causal association between PM2.5 and BMD. The multivariate Mendelian randomization (MVMR) study was designed to perform mediation analyses, exclude possible confounders and calculate the proportion of mediation. Subsequently, we used Bayesian colocalization analysis to consolidate the MR results. Finally, using drug-target MR design, we evaluated the potential repurposing of tumor necrosis factor (TNF) inhibitors for the treatment of osteoporosis (OP). The results of the analyses show that BMD is negatively influenced by PM2.5 (Inverse variance weighted [IVW] beta [β] = -0.288, 95% confidence interval [CI]: -0.534 - -0.042, P < 0.05). PM2.5 has a positive causal association with TNF (IVW β = 1.564, 95% CI: 0.155 - 2.973, P < 0.05) and a negative causal association with protachykinin-1 (TAC-1) (IVW β = -1.654, 95% CI: -3.063 - -0.244, P < 0.05). TNF has a negative causal association with BMD (Wald ratio β = -0.082, 95% CI: -0.165 - 0.000, P < 0.05) and TAC-1 has a positive causal association with BMD (IVW β = 0.042, 95% CI: 0.007 - 0.077, P < 0.05). After adjusting TNF and TAC-1, PM2.5 has no causal association with BMD (IVW β = -0.200, 95% CI: -0.579 - 0.179, P > 0.05). After adjusting PM2.5 and TAC-1, there was still a negative causal association between TNF and BMD (IVW β = -0.089, 95% CI: -0.166 - -0.012, P < 0.05). In the final drug-target MR study, the protective effect of TNF/TNF receptor 1 (TNFR1) inhibition on BMD was observed. For every 10% decrease of circulating C-reactive protein (CRP) achieved by TNF/TNF receptor 1 (TNFR1) blockade, β was 0.540 (95% CI: 0.040-1.040) for BMD. We found a negative causal association between PM2.5 and BMD and that causal association was mediated by TNF. The results of drug-target MR do support TNFR1 as a promising target for OP prevention among the general population.

Short-term exposure to gaseous pollutants is neglected factors for knee osteoarthritis: evidence from a humid subtropical region of China

Few studies were performed on the impact of exposure to gaseous pollutants on the risk of knee osteoarthritis (KOA). We conducted this study to analyze the association between short-term exposure to gaseous pollutants and the risk of hospitalizations for KOA. A total of 2952 KOA hospitalizations derived from two hospitals in Hefei, and the relationship between gaseous pollutants and KOA hospitalizations was analyzed by a distributed lag non-linear model combined with a generalized linear model. We found that the decreased risk of hospitalizations for KOA were both related to exposure to NO2 (RR = 0.993, lag19 day) and O3 (RR = 0.984, lag0 day), while exposure to CO could increase the risk of hospitalizations for KOA (RR = 1.076, lag2 day). Stratified analyses suggested that the KOA patients < 65 years were more susceptible to O3 exposure, and the female, male, patients ≥ 65 years, and patients < 65 years were both more sensitive to CO exposure. Our findings demonstrated that exposure to NO2, O3 resulted in a decreased risk for KOA hospitalizations, and CO exposure might increase the risk of KOA hospitalizations.

A comprehensive review on environmental pollutants and osteoporosis: Insights into molecular pathways

A significant problem that has an impact on community wellbeing is environmental pollution. Environmental pollution due to air, water, or soil pollutants might pose a severe risk to global health, necessitating intense scientific effort. Osteoporosis is a common chronic condition with substantial clinical implications on mortality, morbidity, and quality of life. It is closely linked to bone fractures. Worldwide, osteoporosis affects around 200 million people, and every year, there are almost 9 million fractures. There is evidence that certain environmental factors may increase the risk of osteoporosis in addition to traditional risk factors. It is crucial to understand the molecular mechanisms at play because there is a connection between osteoporosis and exposure to environmental pollutants such as heavy metals, air pollutants, endocrine disruptors, metal ions and trace elements. Hence, in this scoping review, we explore potential explanations for the link between pollutants and bone deterioration through deep insights into molecular pathways. Understanding and recognizing these pollutants as modifiable risk factors for osteoporosis would possibly help to enhance environmental policy thereby aiding in the improvement of bone health and improving patient quality of life.

Ambient PM2.5 Exposure and Bone Homeostasis: Analysis of UK Biobank Data and Experimental Studies in Mice and in Vitro

BACKGROUND

Previous evidence has identified exposure to fine ambient particulate matter (PM 2.5 ) as a leading risk factor for adverse health outcomes. However, to date, only a few studies have examined the potential association between long-term exposure to PM 2.5 and bone homeostasis.

OBJECTIVE

We sought to examine the relationship between long-term PM 2.5 exposure and bone health and explore its potential mechanism.

METHODS

This research included both observational and experimental studies. First, based on human data from UK Biobank, linear regression was used to explore the associations between long-term exposure to PM 2.5 (i.e., annual average PM 2.5 concentration for 2010) and bone mineral density [BMD; i.e., heel BMD (n = 37,440 ) and femur neck and lumbar spine BMD (n = 29,766 )], which were measured during 2014-2020. For the experimental animal study, C57BL/6 male mice were assigned to ambient PM 2.5 or filtered air for 6 months via a whole-body exposure system. Micro-computed tomography analyses were applied to measure BMD and bone microstructures. Biomarkers for bone turnover and inflammation were examined with histological staining, immunohistochemistry staining, and enzyme-linked immunosorbent assay. We also performed tartrate-resistant acid phosphatase (TRAP) staining and bone resorption assay to determine the effect of PM 2.5 exposure on osteoclast activity in vitro. In addition, the potential downstream regulators were assessed by real-time polymerase chain reaction and western blot.

RESULTS

We observed that long-term exposure to PM 2.5 was significantly associated with lower BMD at different anatomical sites, according to the analysis of UK Biobank data. In experimental study, mice exposed long-term to PM 2.5 exhibited excessive osteoclastogenesis, dysregulated osteogenesis, higher tumor necrosis factor-alpha (TNF- α ) expression, and shorter femur length than control mice, but they demonstrated no significant differences in femur structure or BMD. In vitro, cells stimulated with conditional medium of PM 2.5 -stimulated macrophages had aberrant osteoclastogenesis and differences in the protein/mRNA expression of members of the TNF- α / Traf 6 / c -Fos pathway, which could be partially rescued by TNF- α inhibition.

DISCUSSION

Our prospective observational evidence suggested that long-term exposure to PM 2.5 is associated with lower BMD and further experimental results demonstrated exposure to PM 2.5 could disrupt bone homeostasis, which may be mediated by inflammation-induced osteoclastogenesis. https://doi.org/10.1289/EHP11646.

Association between traffic-related air pollution and osteoporotic fracture hospitalizations in inland and coastal areas: evidences from the central areas of two cities in Shandong Province, China

Our result showed that short-term exposure to traffic-related air pollutants (TRAPs) might increase the risk of hospitalizations for osteoporotic fractures. It was suggested that government should formulate emission reduction policies to protect the health of citizens.

INTRODUCTION

As the main source of urban air pollution in China, exhaust emissions of motor vehicles have been linked to adverse health outcomes, but evidence of the relationship between short-term exposure to TRAPs and osteoporotic fractures is still relatively rare.

METHODS

In this study, a total of 5044 inpatients from an inland city (Jinan) and a coastal city (Qingdao), two cities with developed transportation in Shandong Province, were included. A generalized additive model (GAM) was used to investigate the association between TRAPs and hospitalizations for osteoporotic fractures. The stratified analyses were performed by gender and age.

RESULTS

Positive associations between TRAPs and osteoporotic fracture hospitalizations were observed. We found that short-term exposure to TRAPs was associated with increased numbers of hospitalizations for osteoporotic fractures. PM2.5 and PM10 were statistically significant associated with hospitalizations for osteoporotic fractures at both single-day and multiday lag structures only in Qingdao, with the strongest associations at lag06 and lag07 [RR=1.0446(95%CI: 1.0018,1.0891) for PM2.5, RR=1.0328(95%CI: 1.0084,1.0578) for PM10]. For NO2 and CO, we found significant associations at lag4 in the single lag structure in Jinan [RR=1.0354 (95%CI: 1.0071, 1.0646) for NO2, RR=1.0014 (95%CI: 1.0002, 1.0025) for CO], while only CO at lag4 was significantly associated with hospitalizations for osteoporotic fractures in Qingdao [1.0038 (1.0012, 1.0063)]. Stratified analyses indicated that the associations were stronger in females and older individuals (65 + years).

CONCLUSION

This study implied that short-term exposure to TRAPs pollution was associated with an increased risk of hospitalizations for osteoporotic fractures. Female patients and patients aged 65 + years appeared to be more vulnerable to TRAPs, suggesting that poor air quality is a modifiable risk factor for osteoporotic fractures.

Outdoor air pollution exposure, bone mineral density, osteoporosis, and osteoporotic fractures: A systematic review and meta-analysis

BACKGROUND

The prevalence of osteoporosis and osteoporotic fractures is expected to increase with the aging of the population in the coming decades. In this study, we systematically reviewed the evidence on the association between exposure to air pollution and osteoporosis-related outcomes.

METHODS

We systematically searched evidence according to the PRISMA on PubMed, Scopus, and Web of Science (until August 2022). The risk of bias (RoB) was assessed using the Risk of Bias in the Non-randomized Studies of Exposures (ROBINS-E) tool. Random effects meta-analysis was applied to calculate combined estimates. We evaluated the heterogeneity using Cochran's Q test and quantified it by I² and tau² statistics. The overall body of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation system (GRADE) tool.

RESULTS

Out of 5254 retrieved articles, 19 studies (11 cross-sectional, seven cohorts, and one case-control) met our inclusion criteria. Most of the studies had a high probability of RoB (n = 17), and only two had a moderate RoB. Different outcomes including bone mineral density, bone mineral content, osteoporotic fracture, osteoporosis, and osteopenia were reported across the studies. The associations were reported for different air pollutants including PM2.5, PM10, nitrogen oxides, nitrogen dioxide, ozone, black carbon, carbon monoxide, sulfur dioxide, nitrogen oxide, and coarse particulate matter. Evidence was suggestive of the negative role of PM10, PM2.5, and nitrogen dioxide (e.g. bone mineral density pooled estimate: -0.02, 95%CI: -0.03: -0.01). The overall body of evidence for most of the exposure-outcome pairs was low and very low.

CONCLUSIONS

The evidence on the association between air pollution exposure and osteoporosis-related outcomes is heterogenic. However, the evidence suggests an increased risk of osteoporotic fracture and osteoporosis in outdoor air pollutants. Due to the small number of studies in each group, also observed heterogeneity, and publication bias, the results should be interpreted with caution.

Ambient air pollution, bone mineral density and osteoporosis: Results from a national population-based cohort study

Evidence concerning the associations of ambient air pollution exposure with bone mineral density and osteoporosis has been mixed. We conducted cross-sectional and prospective analysis of the associations between air pollution exposure and osteoporosis using data from UK Biobank study. Estimated bone mineral density (eBMD) of each participant at baseline survey was calculated using quantitative ultrasound data, and incident osteoporosis cases were identified during the follow-up period according to health-related records. Air pollution concentrations were assessed using land use regression models. We fitted multivariable linear and logistic regression models to estimate the associations of air pollution with eBMD and osteoporosis prevalence at baseline. We applied cox proportional hazard regression models to assess the relationships between air pollution and osteoporosis incidence. Among the 341,311 participants at baseline, higher air pollution exposure was associated with lower eBMD levels and increased odds of osteoporosis prevalence. For example, an IQR increase in PM_2.5, PM_2.5 absorbance, PM₁₀, NO₂ and NO_x levels were associated with 0.0018 (95% CI: 0.0012, 0.0023) to 0.0052 (95% CI: 0.0046, 0.0058) g/cm² decrease in eBMD. A total of 330,988 participants without osteoporosis were followed up for an average of 12.0 years. We identified 8105 incident osteoporosis cases (456 cases with pathological fracture and 7634 cases without pathological fracture) during the follow-up. The hazard ratios for an interquartile range increase in PM_2.5, PM_2.5 absorbance, PM₁₀, NO₂ and NO_x were 1.09 (95% CI: 1.06, 1.12), 1.04 (95% CI: 1.02, 1.07), 1.04 (95% CI: 1.01, 1.07), 1.07 (95% CI: 1.04, 1.10), and 1.06 (95% CI: 1.03, 1.09), respectively. Our study suggests that ambient air pollution might be a risk factor of decreased bone mineral density and osteoporosis incidence.

Proximity to major roads and the incidence of osteoporotic fractures in elderly women: The BONE study in Beijing

Background

There is growing evidence to suggest that living near major roads (and suffering from the air pollution of urban streets) can have an adverse effect on bone health. However, little is known about its relationship to fractures caused by osteoporosis.

Objective

This study was designed to investigate the relationship between residents living near major roads and the incidence of osteoporotic fractures.

Methods

A retrospective cohort of 529 subjects was established based on community populations in older women aged 65-91. All participants lived in Beijing between September 27, 2007 and September 26, 2017. The distance between the residential sites of the subjects and the main roads was determined by the authors. Osteoporotic fracture diagnosis was based on medical histories and imaging examinations (DXA and X-rays). The Cox proportional hazard model was used to assess the association between traffic proximity and osteoporotic fractures, with suitable adjustments for individual and background factors.

Results

The age range of all participants was 65-91 years, with an average age of 75.8 years (and a standard deviation 6.8 years). Of these, 19 (3.59%) suffered from diabetes, and 48 (9%) had hypertension; 85 (14%) families had annual incomes below US $30,000 and 402 (76%) had received a secondary school education or higher. Nearly 25% of people lived within 50 m of a main road, while 50% lived within 300 m. Between 2007 and 2017, a total of 96 osteoporotic fractures were observed. For people living <50 m from a main road, the adjusted hazard ratio (HR) for osteoporotic fractures was 2.509 (95% CI 1.345-4.680), while it was 1.830 (95% CI 1.029-3.255) for those living at a distance of 50-300 m from a main road vs. those living further than 300 m away.

Conclusion

In this community-based cohort, living near a major road was associated with a higher incidence of osteoporotic fractures.

Association of air pollutants and osteoporosis risk: The modifying effect of genetic predisposition

BACKGROUND

Limited studies have examined the association between air pollutants and osteoporosis incidence; however, the results are conflicting. We aimed to quantify the effects of selected air pollutants on osteoporosis risk and explore the modifying effect of genetic predisposition.

METHODS

A total of 422,955 subjects who did not have osteoporosis at baseline in the UK Biobank were included from 2006 to 2010. We conducted a Cox proportional hazards model with adjustment for covariates to examine the association between air pollutant scores and individual air pollutants and incident osteoporosis. Furthermore, a polygenic risk score (PRS) of osteoporosis was built and examined to determine whether genetic susceptibility modified the effect of air pollutants on osteoporosis. The relationship between air pollutants and osteoporosis was examined by using a restricted cubic spline (RCS) method.

RESULTS

After confounder adjustment, the results showed a remarkable increase in the risk of osteoporosis with each 10 unit increase in exposure to air pollution (hazard ratio: 1.06, 95 % confidence interval: 1.03-1.08), PM_2.5 (1.94, 1.52-2.48), NO₂ (1.06, 1.02-1.10), and NO_X (1.03, 1.01-1.04). However, no significant association was observed between PM₁₀ or PM_2.5-10 exposure and osteoporosis. Subjects with high air pollutant exposure levels and a high PRS had a noteworthy increase in osteoporosis risk compared to those with low air pollutant exposure levels and a low PRS. Air pollutants and genetic variants exerted additive effects on the risk of osteoporosis. Positive correlations were observed between osteoporosis and PM_2.5 (P < 0.001), NO₂ (P = 0.001), and NOx (P = 0.002) exposure.

CONCLUSIONS

Exposure to PM_2.5, NO₂ and NOx was associated with an increase in osteoporosis risk, and this effect was more pronounced in populations with high genetic risk. The association between PM_2.5, NO₂ and NOx exposure and osteoporosis is modified by genetic variations.

Long-term exposure to air pollution might decrease bone mineral density T-score and increase the prevalence of osteoporosis in Hubei province: evidence from China Osteoporosis Prevalence Study

We hypothesized that air pollution could cause oxidative damage and inflammation in the human body, which was linked to bone loss. Our result showed that long-term exposure to air pollution might decrease bone mineral density (BMD) T-score and increase the prevalence of osteoporosis in Hubei province.

INTRODUCTION

Osteoporosis is becoming an increasingly serious public health problem with the advent of global aging. Long-term exposure to air pollution has been linked to multitudinous adverse health outcomes, but evidence is still relatively limited and inconsistent for BMD T-score and osteoporosis. This study aimed at exploring the associations between long-term exposure to air pollution and BMD T-score and osteoporosis.

METHODS

The Hubei part of the China Osteoporosis Prevalence Study was extracted. Data on air pollutants were collected by the national air quality real-time release platform of China Environmental Monitoring Station. Linear mixed models and multilevel logistic regression analyses were performed to assess the associations between air pollution and BMD T-score and osteoporosis, respectively. Subgroup analyses were conducted to identify vulnerable populations.

RESULTS

A total of 1845 participants were included in this cross-section study. Per 10 ug/m³ increase in PM_2.5 and SO₂ were associated with 0.20 (95% CI: 0.04, 0.36) and 0.31 (95% CI: 0.11, 0.51) decrease in BMD T-score of the neck of femur, respectively. Per 10 ug/m³ increase in CO was linked with 0.03 (95% CI: 0.02, 0.05) decrease in BMD T-score of the total hip. Per 1 ug/m³ increase in PM_2.5 was associated with 5% increase in the prevalence of osteoporosis in all participants. In general, the higher concentrations of PM_2.5 with the more adverse effect on osteoporosis (P for trend = 0.01). The impact of PM_2.5 on osteoporosis in males was higher than that in females [1.29, 95% CI (1.11, 1.50) vs 1.01, 95% CI (0.95, 1.07)]. Per 1 ug/m³ increase in PM₁₀ corresponded with 4% elevation in the risks of osteoporosis in rural population. The ORs (95% CI) for the association of osteoporosis and NO₂ in ever/current smoking and drinking population were 1.07 (1.01, 1.13) and 1.05 (1.00, 1.09), respectively. SO₂ had a statistically significant positive effect on people with comorbidity [OR = 1.10, (95% CI: 1.00 to 1.21)], while none in people without comorbidity [OR = 0.96, (95% CI: 0.88 to 1.05)].

CONCLUSION

Our study provided evidence that long-term exposure to PM_2.5 was linked with the decreased BMD T-score and increased risk of osteoporosis among all participants. The adverse impacts of PM_2.5, PM₁₀, and NO₂ were larger in males than in females. People having comorbidity, living in rural areas, and current/ever smoking or drinking were more vulnerable to air pollution. Public health departments should consider air pollution to formulate better preventive measures for osteoporosis.

Long-term exposure to air pollution increases hip fracture incidence rate and related mortality: analysis of National Hip Fracture Database

To explore the association of air pollution and hip fracture and related mortality in the UK. The average levels of PM2.5, PM10, and NO2 exhibited a positive association with hip fracture and short-term mortality while O₃ did not. Our study highlights the association of air pollution and hip fracture.

INTRODUCTION

Until now, the influence of air pollution on bone mineral density and associated fractures has drawn little attention, and the consequences are controversial. To investigate the association between air pollution and hip fracture incidence and related short-term mortality.

METHODS

We constructed a cohort of all the National Hip Fracture Database beneficiaries (513,540 patients) in the UK from 2013 to 2018. Per year averages of PM_2.5, PM₁₀, O₃, NO₂, and SO₂ were estimated according to the person's residence. The incidence rate ratio with 95% confidence interval and all-cause mortality within 30-day post-fracture (ACM30D) rate ratios were estimated using generalized additive models.

RESULTS

The average levels of PM_2.5, PM₁₀, and NO₂ exhibited a positive association with the incidence rate of hip fracture (IHF) and ACM30D. Whereas, this association was negative for O₃ levels. Each increase of 5 μg per cubic meter in PM_2.5, PM₁₀, and NO₂ leads to 9.5%, 9.2%, and 4.1% higher hip fracture rate, respectively, and also 9.3%, 8.3%, and 2.9% higher ACM30D, respectively. When we restricted the analysis to low-level exposure of air pollutants, similar results were obtained.

CONCLUSION

Our study found a moderate, positive association between IHF, ACM30D, and the levels of specific air pollutants in the entire National Hip Fracture Database population. A reduction in the levels of PM_2.5, PM₁₀, and NO₂ may decrease the hip fracture incidence rate and associated short-term mortality in older adults. Our study highlights the influence of air pollution on hip fracture.

The potential osteoporosis due to exposure to particulate matter in ambient air: Mechanisms and preventive methods

Air pollution and health consequences associated with exposure to air pollutants, such as particulate matter, are of serious concerns in societies. Over the recent years, numerous studies have investigated the relation of many diseases with air pollutants. This review used a search strategy to provide the comprehensive information on the relationship between particle matters and osteoporosis. To this end, three search databases were used to find the articles focused on particle matters and osteoporosis. After the screening process, 13 articles related to the purpose of the study were selected and the relevant data were extracted. The results indicated that osteoporosis is significantly associated with PM₁₀. However, this association with PM_2.5 remains unclear. In addition, particle materials indirectly lead to the osteoporosis and bone fractures as a consequence of reduced UV-B, reduced adsorption of vitamin D. Furthermore, they can lead to other diseases by use of drugs with adverse effects on bone health, and creating conditions that may increase the risk of falling in the elderly. This review shows that although more accurate research is needed to determine the mechanism and risk of exposure to particulate matter in the air on bone health, the negative effects of this pollutant on bone mineral density (BMD) are evident.Implications: PM is usually classified by its size or aerodynamic diameter; PM10 denotes particles < 10 µm in diameter; PM2.5 particles are <2.5 µm in diameter. Many epidemiological studies have shown that short-term exposure to PM might reduce lung function. However, short-term effects might be reversible, and the main concern is attributed to long-term exposure. A major public health concern that may be affected by numerous metabolic and even environmental risk factors is osteoporosis. The purpose of this systematic review was to investigate the role of PM in the occurrence or exacerbation of osteoporosis in citizens.

Living near greenness is associated with higher bone strength: A large cross-sectional epidemiological study in China

BACKGROUND

Living near green spaces may benefit various health outcomes. However, no studies have investigated the greenness-bone linkage in the general population. Moreover, to which extent ambient air pollution (AAP), physical activity (PA), and body mass index (BMI) mediate this relationship remains unclear. We aimed to explore the association between greenness and bone strength and the potential mediating roles of AAP, PA, and BMI in Chinese adults.

METHODS

This cross-sectional analysis enrolled 66,053 adults from the China Multi-Ethnic Cohort in 2018-2019. The normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) were employed to define residential greenness. The calcaneus quantitative ultrasound index (QUI) was used to indicate bone strength. Multiple linear regression models and mediation analyses were used to estimate the residential greenness-bone strength association and potential pathways operating through AAP (represented by PM_2.5 [particulate matter <2.5 μm in diameter]), PA, and BMI. Stratification analyses were performed to identify susceptible populations.

RESULTS

Higher residential exposure to greenness was significantly associated with an increase in QUI, with changes (95% confidence interval) of 3.28 (3.05, 3.50), 3.57 (3.34, 3.80), 2.68 (2.46, 2.90), and 2.93 (2.71, 3.15) for every interquartile range increase in NDVI_500m, NDVI_1000m, EVI_500m, and EVI_1000m, respectively. Sex, urbanicity, annual family income, smoking, and drinking significantly modified the association of greenness-bone strength, with more remarkable associations in males, urban residents, subjects from wealthier families, smokers, and drinkers. For the NDVI_500m/EVI_500m-QUI relationship, the positive mediating roles of PM_2.5 and PA were 6.70%/8.50 and 2.43%/2.69%, respectively, whereas those negative for BMI and PA-BMI were 0.88%/1.06% and 0.05%/0.05%, respectively.

CONCLUSION

Living in a greener area may predict higher bone strength, particularly among males, urban residents, wealthier people, smokers, and drinkers. AAP, PA, BMI, and other factors may partially mediate the positive association. Our findings underscore the importance of optimizing greenness planning and management policies.

Osteoporosis in Patients With Respiratory Diseases

Climate change, environmental pollution, and virus epidemics have sharply increased the number of patients suffering from respiratory diseases in recent years. Prolonged periods of illness and drug use increase the occurrence of complications in these patients. Osteoporosis is the common bone metabolism disease with respiratory disturbance, which affects prognosis and increases mortality of patients. The problem of osteoporosis in patients with respiratory diseases needs more attention. In this review, we concluded the characteristics of osteoporosis in some respiratory diseases including COPD, asthma, COVID-19, tuberculosis, and lung cancer. We revealed that hypoxia was the common pathogenesis of osteoporosis secondary to respiratory diseases, with malnutrition and corticosteroid abuse driving the progression of osteoporosis. Hypoxia-induced ROS accumulation and activated HIF-1α lead to attenuated osteogenesis and enhanced osteoclastogenesis in patients with respiratory diseases. Tuberculosis and cancer also invaded bone tissue and reduced bone strength by direct infiltration. For the treatment of osteoporosis in respiratory patients, oral-optimized bisphosphonates were the best treatment modality. Vitamin D was a necessary supplement, both for calcium absorption in osteogenesis and for improvement of respiratory lesions. Reasonable adjustment of the dose and course of corticosteroids according to the etiology and condition of patients is beneficial to prevent the occurrence and development of osteoporosis. Additionally, HIF-1α was a potential target for the treatment of osteoporosis in respiratory patients, which could be activated under hypoxia condition and involved in the process of bone remodeling.

Overview of Traditional and Environmental Factors Related to Bone Health

Bone mass in adulthood depends on growth and mineralization acquired during childhood and adolescence. It is well known that these stages of life are crucial for bone development, where genetic, nutritional, hormonal, and lifestyle factors play a significant role. Bone loss is normally a natural and slow process that begins years later after the peak bone mass is achieved and continues throughout the lifespan. Lifestyle choices in childhood and adolescence such as minimal physical activity, excessive caffeine or carbonated beverages intake, malnutrition, cigarette use, or high alcohol consumption and other factors like environmental pollutants can also negatively affect bone health and accelerate the bone loss process. The aim of this work is an overview of risk factors associated with inadequate bone health in early life.

The Association Between Long-term Exposure to Ambient Air Pollution and Bone Strength in China

CONTEXT

Evidence regarding the association of long-term exposure to air pollution on bone strength or osteoporosis is rare, especially in highly polluted low- and middle-income countries. Little is known about whether the association between air pollution and bone strength changes at different bone strength distributions.

OBJECTIVE

Using the baseline data from the China Multi-Ethnic Cohort, we investigated the association between long-term air pollution exposure and bone strength.

METHODS

We used multiple linear models to estimate the association between air pollution and bone strength, and we conducted quantile regression models to investigate the variation of this association in the distribution of bone strength. The 3-year concentrations of PM1, PM2.5, PM10, and NO2 for each participant were assessed using spatial statistical models. Bone strength was expressed by the calcaneus quantitative ultrasound index (QUI) measured by quantitative ultrasound, with higher QUI values indicating greater bone strength.

RESULTS

A total of 66 598 participants were included. Our analysis shows that every 10 μg/m3 increase in 3-year average PM1, PM2.5, PM10, and NO2 was associated with -5.38 units (95% CI: -6.17, -4.60), -1.89 units (95% CI: -2.33, -1.44), -0.77 units (95% CI: -1.08, -0.47), and -2.02 units (95% CI: -2.32, -1.71) changes in the QUI, respectively. In addition, populations with higher bone strength may be more susceptible to air pollution.

CONCLUSION

Long-term exposure to PM1, PM2.5, PM10, and NO2 was significantly associated with decreased bone strength in southwestern China adults. Air pollution exposure has a more substantial adverse effect on bones among populations with higher bone strength.

Association between outdoor particulate air pollution and the risk of osteoporosis: a systematic review and meta-analysis

Air pollution is a major threat to global health, which is associated with several adverse health outcomes and increased mortality. Few studies have investigated the association between air pollution and osteoporosis, and their findings were inconclusive. Our objective is to determine whether exposure to outdoor air pollution is causally associated with risk of osteoporosis. A systematic literature search of PubMed, Web of Science, Embase, and Cochrane Library for publications up to December 2020 was conducted for studies reporting the association between air pollution and osteoporosis. Meta-analysis was performed to estimate the pooled effect size of air pollution on osteoporosis using the relative risk (RR) and 95% confidence intervals (95% CI). Quality assessment was conducted, and all statistical analyses were performed by RevMan 5.3 software. Our search identified 9 eligible studies involving 9,371,212 patients. Meta-analysis revealed that there was an increased risk of osteoporosis (total body BMD and hip fracture) as a result of exposure to air pollution including PM_2.5 and NO₂. However, no significant excess risk of osteoporosis was found regardless of PM₁₀, NO, and O₃. In spite of a few number of epidemiological studies selected in the present literature review, this study indicated that the increased exposure to air pollutants was positively associated with high risk of osteoporosis. Further cohort studies with large sample sizes are needed to investigate different constituents and the duration of exposure of air pollutants.

Prenatal air pollution exposure to diesel exhaust induces cardiometabolic disorders in adulthood in a sex-specific manner

BACKGROUND

Results from observational and experimental studies indicate that exposure to air pollutants during gestation reduces birth weight, whereas little is known on potential cardiometabolic consequences for the offspring at adulthood.

OBJECTIVES

Our aim was to evaluate the long-term effects of gestational exposure to diesel engine exhaust (DE) on adult offspring phenotype in a rabbit model.

METHODS

The protocol was designed to mimic human exposure in large European cities. Females rabbits were exposed to diluted (1 mg/m³) DE (exposed, n = 9) or clean air (controls, n = 7), from 3 days after mating, 2 h/d and 5 d/wk in a nose-only inhalation system throughout gestation (gestation days 3-27). After birth and weaning, 72 offspring (47 exposed and 25 controls) were raised until adulthood (7.5 months) to evaluate their cardio-metabolic status, including the monitoring of body weight and food intake, fasting biochemistry, body composition (iDXA), cardiovascular parameters and glucose tolerance. After a metabolic challenge (high fat diet in males and gestation in females), animals were euthanized for postmortem phenotyping.

RESULTS

Sex-specific responses to maternal exposure were observed in adult offspring. Age-related increases in blood pressure (p = 0.058), glycaemia (p = 0.029), and perirenal fat mass (p = 0.026) as well as reductions in HDL-cholesterol (p = 0.025) and fat-to-body weight ratio (p = 0.011) were observed in exposed males, suggesting a metabolic syndrome. Almost only trends were observed in exposed females with higher triglycerides and decreased bone density compared to control females. Metabolic challenges triggered or amplified some biological responses, especially in females.

CONCLUSIONS

In utero exposure to air pollution predisposed rabbit offspring to cardiometabolic disorders in a sex-specific manner.

Particulate Air Pollution and Osteoporosis: A Systematic Review

Air pollution is associated with inflammation and oxidative stress, which predispose to several chronic diseases in human. Emerging evidence suggests that the severity and progression of osteoporosis are directly associated with inflammation induced by air pollutants like particulate matter (PM). This systematic review examined the relationship between PM and bone health or fractures. A comprehensive literature search was conducted from January until February 2021 using the PubMed, Scopus, Web of Science, Google Scholar and Cochrane Library databases. Human cross-sectional, cohort and case-control studies were considered. Of the 1500 papers identified, 14 articles were included based on the inclusion and exclusion criteria. The air pollution index investigated by most studies were PM2.5 and PM10. Current studies demonstrated inconsistent associations between PM and osteoporosis risk or fractures, which may partly due to the heterogeneity in subjects' characteristics, study design and analysis. In conclusion, there is an inconclusive relationship between osteoporosis risk and fracture and PM exposures which require further validation.

Long-term exposure to fine particulate matter and osteoporotic fracture: A case-control study in Taiwan

Few studies have explored the relationship between long-term exposure to particulate matter with an aerodynamic diameter of ≤2.5 μm (PM_2.5) and osteoporotic fracture, particularly in high PM_2.5 level areas. The aim of this study was to assess the association between long-term exposure to PM_2.5 and osteoporotic fracture. We performed a matched case-control study of 16,175 participants obtained from a hospital registry during 2005-2014 in Taiwan. A major osteoporotic fracture was defined as a fracture of the spine, hip, proximal humerus, and forearm. We applied satellite-based spatiotemporal models with 1-km resolution to individually calculate the 1-year average PM_2.5 concentration before the index date which was defined as the first visit date for the osteoporotic fracture. Logistic regression models with and without potential confounding factors were used to estimate odds ratios (OR) and 95% confidence intervals (CI) between PM_2.5 and osteoporotic fracture, whereas a restricted cubic spline model was used to estimate the dose-response relationship. The sample's median age was 44.7 years (interquartile range: 30.7, 63.1 years). We observed that long-term PM_2.5 exposure was associated with osteoporotic fracture, the OR was 1.12 (95% CI: 1.03, 1.22) per 10-μg/m³ increase in PM_2.5 in women. In the dose-response association, the OR of osteoporotic fracture was significantly increased for PM_2.5 exposures more than 41 μg/m³. We did not find a significant association between PM_2.5 (per 10-μg/m³ increase) and osteoporotic fracture among overall population (adjusted OR, 1.02 [95% CI, 0.97 to 1.08]) and men (adjusted OR, 0.94 [95% CI, 0.86 to 1.02]). The results of the stratified analysis showed that women were more sensitive to the adverse impact of PM2.5 that were men, and evidence was obtained of sex-based effect modification (P for interaction = 0.002). Our findings suggest that long-term exposure to PM_2.5 is associated with osteoporotic fracture, particularly among women.

Molecular and cellular mechanisms linking air pollution and bone damage

Air pollution is the second most important risk factor associated with noncommunicable diseases after smoking. The effects of pollution on health are commonly attributable to particulate matter (PM), a complex mixture of particles suspended in the air. PM can penetrate the lower respiratory tract and has harmful direct and indirect effects on different organs and tissues. Direct effects are caused by the ability of PM components to cross the respiratory membrane and enter the bloodstream; indirect effects are systemic consequences of the local airway response. Recent work suggests that PM is an independent risk factor for low bone mineral density and osteoporosis-related fractures. Osteoporosis is a common age-related disease closely linked to bone fractures, with severe clinical consequences affecting quality of life, morbidity, and mortality. In this review, we discuss potential mechanisms behind the association between outdoor air pollution, especially PM, and bone damage. The discussion features four main mechanisms: 1) several different atmospheric pollutants can induce low-grade systemic inflammation, which affects bone metabolism through a specific effect of cytokines such as TNFα, IL-1β, IL-6, and IL-17 on osteoblast and osteoclast differentiation and function; 2) some pollutants, particularly certain gas and metal compounds, can cause oxidative damage in the airway and bone cells; 3) different groups of pollutants can act as endocrine disruptors when binding to the receptors in bone cells, changing their functioning; and 4) air pollution can directly and indirectly cause vitamin D deficiency. Characterizing these mechanisms will better define the physiopathology of bone damage, and recognizing air pollution as a modifiable risk factor for osteoporosis will inform environmental policies. Such knowledge will also guide the prevention of fractures due to fragility and help reduce health-related costs.

Long-term exposure to air pollution might increase prevalence of osteoporosis in Chinese rural population

OBJECTIVES

The associations of long-term exposure to air pollution with osteoporosis are rarely reported, especially in rural China. This study aimed to explore the association among rural Chinese population.

METHODS

A total of 8033 participants (18-79 years) derived from the Henan Rural Cohort Study (n = 39,259) were included in this cross-sectional study. Exposure to air pollutants was estimated using machine learning algorithms with satellite remote sensing, land use information, and meteorological data [including particulate matter with aerodynamic diameters ≤1.0 μm (PM₁), ≤2.5 μm (PM_2.5), and ≤10 μm (PM₁₀), and nitrogen dioxide (NO₂)]. The bone mineral density of each individual was measured by using ultrasonic bone density apparatus and osteoporosis was defined based on the T-score ≤ -2.5. Multiple logistic regression models were used to examine the association of air pollution and osteoporosis prevalence.

RESULTS

We observed that per 1 μg/m³ increase in PM₁, PM_2.5, PM₁₀ and NO₂ were associated with a 14.9%, 14.6%, 7.3%, and 16.5% elevated risk of osteoporosis. Compared with individuals in the first quartile, individuals in the fourth quartile had higher odds ratio (OR) of osteoporosis (P-trend < 0.001), the ORs (95% confidence interval) were 2.08 (1.72, 2.50) for PM₁, 2.28 (1.90, 2.74) for PM_2.5, 1.93 (1.60, 2.32) for PM₁₀, and 2.02 (1.68, 2.41) for NO₂. It was estimated that 20.29%-24.36% of osteoporosis cases could be attributable to air pollution in the rural population from China.

CONCLUSIONS

Long-term exposure to air pollutants were positively associated with high-risk of osteoporosis, indicated that improving air quality may be beneficial to improve rural residents health.

The toxicology of air pollution predicts its epidemiology

The epidemiologic investigation has successively delineated associations of air pollution exposure with non-malignant and malignant lung disease, cardiovascular disease, cerebrovascular disease, pregnancy outcomes, perinatal effects and other extra-pulmonary disease including diabetes. Defining these relationships between air pollution exposure and human health closely parallels results of an earlier epidemiologic investigation into cigarette smoking and environmental tobacco smoke (ETS), two other particle-related exposures. Humic-like substances (HULIS) have been identified as a chemical component common to cigarette smoke and air pollution particles. Toxicology studies provide evidence that a disruption of iron homeostasis with sequestration of host metal by HULIS is a fundamental mechanistic pathway through which biological effects are initiated by cigarette smoke and air pollution particles. As a result of a common chemical component and a shared mechanistic pathway, it should be possible to extrapolate from the epidemiology of cigarette smoking and ETS to predict associations of air pollution exposure with human disease, which are currently unrecognized. Accordingly, it is anticipated that the forthcoming epidemiologic investigation will demonstrate relationships of air pollution with COPD causation, peripheral vascular disease, hypertension, renal disease, digestive disease, loss of bone mass/risk of fractures, dental disease, eye disease, fertility problems, and extrapulmonary malignancies.

Air pollution, weight loss and metabolic benefits of bariatric surgery: a potential model for study of metabolic effects of environmental exposures

BACKGROUND

Emerging experimental evidence suggests that air pollution may contribute to development of obesity and diabetes, but studies of children are limited.

OBJECTIVES

We hypothesized that pollution effects would be magnified after bariatric surgery for treatment of obesity, reducing benefits of surgery.

METHODS

In 75 obese adolescents, excess weight loss (EWL), high-density lipoprotein (HDL) cholesterol, triglycerides, alkaline phosphatase (ALP) and hemoglobin A1c (HbA_1c ) were measured prospectively at baseline and following laparoscopic adjustable gastric banding (LAGB). Residential distances to major roads and the average two-year follow-up exposure to particulate matter <2.5 μm (PM_2.5 ), nitrogen dioxide (NO₂ ) and ozone were estimated. Associations of exposure with change in outcome and with attained outcome two years post-surgery were examined.

RESULTS

Major-roadway proximity was associated with reduced EWL and less improvement in lipid profile and ALP after surgery. NO₂ was associated with less improvement in HbA_1c and lower attained HDL levels and change in triglycerides over two years post-surgery. PM_2.5 was associated with reduced EWL and reduced beneficial change or attained levels for all outcomes except HbA_1c .

CONCLUSIONS

Near-roadway, PM_2.5 and NO₂ exposures at levels common in developed countries were associated with reduced EWL and metabolic benefits of LAGB. This novel approach provides a model for investigating metabolic effects of other exposures.

Association of air particulate pollution with bone loss over time and bone fracture risk: analysis of data from two independent studies

BACKGROUND

Air particulate matter (PM) is a ubiquitous environmental exposure associated with oxidation, inflammation, and age-related chronic disease. Whether PM is associated with loss of bone mineral density (BMD) and risk of bone fractures is undetermined.

METHODS

We conducted two complementary studies of: (i) long-term PM <2.5 μm (PM_2.5) levels and osteoporosis-related fracture hospital admissions among 9.2 million Medicare enrollees of the Northeast/Mid-Atlantic United States between 2003-2010; (ii) long-term black carbon [BC] and PM_2.5 levels, serum calcium homeostasis biomarkers (parathyroid hormone, calcium, and 25-hydroxyvitamin D), and annualized BMD reduction over a 8-year follow-up of 692 middle-aged (46.7±12.3 yrs), low-income BACH/Bone cohort participants.

FINDINGS

In the Medicare analysis, risk of bone fracture admissions at osteoporosis-related sites was greater in areas with higher PM_2.5 levels (Risk ratio [RR] 1.041, 95% Confidence Interval [CI], 1.030, 1.051). This risk was particularly high among low-income communities (RR 1.076; 95% CI, 1.052, 1.100). In the longitudinal BACH/Bone study, baseline BC and PM_2.5 levels were associated with lower serum PTH (Estimate for baseline one interquartile increase in 1-year average BC= -1.16, 95% CI -1.93, -0.38; Estimate for baseline one interquartile increase in 1-year average PM_2.5= -7.39; 95%CI -14.17, -0.61). BC level was associated with higher BMD loss over time at multiple anatomical sites, including femoral neck (-0.08%/year per one interquartile increase; 95% CI -0.14, -0.02%/year) and ultradistal radius (-0.06%/year per one interquartile increase; 95% CI -0.12, -0.01%/year).

INTERPRETATION

Our results suggest that poor air quality is a modifiable risk factor for bone fractures and osteoporosis, especially in low-income communities.

The association of liver fat content and serum alanine aminotransferase with bone mineral density in middle-aged and elderly Chinese men and postmenopausal women

Background

Recent studies have linked non-alcoholic fatty liver disease (NAFLD) to a reduced bone mineral density (BMD). We aimed to detect the quantitative association of liver fat content (LFC) and serum alanine aminotransferase (ALT) with BMD in a middle-aged and elderly Chinese population.

Methods

The lumbar spine, hip and whole body BMDs were measured using dual-energy x-ray absorptiometry (Lunar iDXA, GE Healthcare) in 1659 Chinese (755 men and 1028 postmenopausal women) from Shanghai Changfeng community. Liver fat content was quantified via an ultrasound quantitative method. Multivariate linear regression analyses were carried out to determine the independent association of LFC and serum ALT with BMD and bone metabolic biomarkers. We also attempted to investigate the synergistic association between LFC and ALT as risk factors for bone mineral loss in Chinese.

Results

Subjects with higher LFC had significantly lower BMD at all skeletal sites. Univariate correlation analysis showed that both LFC and ALT were inversely associated with BMD at the spine (r = −0.116, P < 0.001 and r = −0.102, P = 0.005), hip (r = −0.095, P = 0.014 and r = −0.075, P = 0.041) and whole body sites (r = −0.134, P < 0.001 and r = −0.164, P < 0.001) in men. After confounders were controlled for, LFC and ALT remained associated with BMD and bone formation biomarkers in men, but not postmenopausal women. When both NAFLD and elevation of ALT were present, there was a significant synergistic worsening of the BMDs at all bone sites.

Conclusions

Liver fat content and serum ALT were inversely correlated with BMD in middle-aged and elderly men. The underlying mechanism might relate to a reduction in osteoblast activity. Elevation of the hepatotoxic biomarker ALT may indicate high risk for osteoporosis in patients with NAFLD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0766-3) contains supplementary material, which is available to authorized users.