Glomerular function in relation to fine airborne particulate matter in a representative population sample

Associations of long-term exposure to PM2.5 and its constituents with children renal function: a national retrospective study in China

INTRODUCTION

Ambient fine particulate matter with aerodynamic diameter ≤2.5 μm (PM2.5) harms adult's renal health. However, research on the associations of PM2.5 and its chemical constituents (black carbon (BC), ammonium ( [Formula: see text] ), nitrate (NO3-), organic matter (OM), and sulfate (SO42-)) with children' kidney health is lacking.

OBJECTIVES

The aim of this research was to estimate the associations between long-term exposures to PM2.5 and its constituents and children' estimated glomerular filtration rate (eGFR).

METHODS

We investigated 9770 children from 5 provinces across China during 2016-2017. The eGFR was calculated from serum creatinine. We estimated the mean concentration of PM2.5 and PM2.5 compositions (BC, [Formula: see text] , NO3-, OM, SO42-) during pregnancy, infancy and preschool period for each subject. A generalized linear mixed-effects model was utilized to estimate associations of PM2.5 and its constituents with eGFR. Stratified analyses were conducted to explore effect modifications of sex and urbanicity.

RESULTS

During the full pregnancy, each interquartile range (IQR) increase in PM2.5 mass (49.07 μg/m3), SO42- (9.14 μg/m3), BC (1.85 μg/m3), [Formula: see text] (7.38 μg/m3), NO3- (12.23 μg/m3) and OM (9.02 μg/m3) was associated with decreased eGFR (ml/min/1.73 m2), with changes of -1.80 (95 % CI: -2.82, -0.78), -1.70 (95 % CI: -2.71, -0.69), -1.83 (95 % CI: -2.63, -1.03), -6.87 (95 % CI: -8.44, -5.30), -7.24 (95 % CI: -9.02, -5.45), and -2.20 (95 % CI: -3.12, -1.28), respectively. In infancy, higher levels of BC, [Formula: see text] , NO3-, and OM were negatively associated with eGFR, and similar associations were found during the preschool period for [Formula: see text] , NO3-, and OM. Furthermore, children living in rural areas were particularly sensitive to PM2.5.

CONCLUSION

Long-term exposures to PM2.5 and some constituents were negatively associated with children's eGFR. Additionally, the associations of [Formula: see text] and NO3- constituents were more pronounced with renal health than the other chemical constituents. Targeted policies are needed to protect kidney health from PM2.5 exposure.

Air pollution-associated chronic kidney disease (APA-CKD): evidence from a cross-sectional study of Niger Delta communities

OBJECTIVE

Air pollution is an emerging risk factor for chronic kidney disease (CKD) that is typically ignored in preventive interventions. This study investigated whether long-term exposure to ambient air pollution in communities near petrochemical industries in the Niger Delta was associated with CKD.

DESIGN

A cross-sectional study with an embedded citizen science inquiry.

SETTINGS

Four communities situated at varying distances from a petrochemical refinery in Niger Delta, Nigeria.

PARTICIPANTS

We obtained sociodemographic, behavioural, exposure history and clinical data from 1460 participants who have resided for at least 5 years in the four communities. A citizen science approach was used to monitor air pollutant concentrations with eight community volunteers.

RESULTS

The mean PM2.5, PM10 and volatile organic compounds (VOC) concentrations exceeded the WHO-acceptable limits in all four communities. CO2 was acceptable in the farthest communities from the refinery, while O3 was within acceptable limits in all communities. The total hazard quotient was relatively higher in the two communities near the refinery (11.27, 11.63) than those farther (9.63, 10.68), F=0.038, p=0.989. The overall prevalence of CKD was 12.3%; it was 17.9% in the community closest to the refinery and 8.0% in the farthest (χ2=18.292, p=0.004). Increasing age was the only independent risk factor for CKD after adjusting for confounding factors and intrahousehold design effect (adjusted OR 1.26; 95% CI 1.09 to 1.45, p=0.002).

CONCLUSION

Long-term exposure to ambient air pollution may increase CKD risk in susceptible populations. Social factors and environmental exposures associated with CKD are prevalent in the communities, necessitating multifaceted and inclusive approaches to mitigate air pollution and the associated kidney disease risks. More studies are required to explore the mechanism of air pollution-associated kidney disease and interventions to reverse or limit it.

Assessment of male creatinine levels and fecundity in couples planning pregnancy: a national cohort study in China

STUDY QUESTION

Is there an association between male creatinine levels and time to pregnancy (TTP) in couples planning pregnancy?

SUMMARY ANSWER

Low and high male creatinine concentrations were associated with reduced couple fecundity.

WHAT IS KNOWN ALREADY

Abundant evidence suggests male creatinine dysfunction is associated with infertility in males with kidney diseases. However, the association of preconception creatinine levels with reduced fecundity among general reproductive-aged couples lacks evidence from an in-depth population study.

STUDY DESIGN, SIZE, DURATION

Based on the population-based cohort study from the National Free Preconception Check-up Projects, 4 023 204 couples were recruited and met the inclusion criteria from 1 January 2015 to 31 December 2017. They were planning pregnancy and were followed up every 3 months until achieving pregnancy as detected by gynaecological ultrasonography or were followed up for 1 year for the analysis of TTP.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cox regression models were used to estimate hazard ratios (HRs) and 95% CI for creatinine deciles. Restricted cubic spline regression was adopted for the dose-response relationship of creatinine with HRs. R statistical software was used for data analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

Of the included participants, 2 756 538 (68.52%) couples successfully conceived. The median male serum creatinine was 81.50 μmol/l. Compared with the reference group (78.00-81.49 μmol/l) including the median creatinine, fecundity in the first (≤64.89 μmol/l), second (64.90-69.99 μmol/l), third (70.00-73.99 μmol/l), and tenth (≥101.00 μmol/l) deciles decreased by 8%, 5%, 2%, and 1%, respectively (Decile 1 Adjusted HR 0.92, 95% CI 0.91-0.92; Decile 2 Adjusted HR 0.95, 95% CI 0.95-0.96; Decile 3 Adjusted HR 0.98, 95% CI 0.97-0.99; Decile 10 Adjusted HR 0.99, 95% CI 0.98-0.99). An inverse-U-shaped association was consistently presented among males such that non-inferiority for fecundity was shown when creatinine was in the 81.66-104.90 μmol/l range (P for non-linearity < 0.001). For males over 40 years old, the risk of fecundity impairment was more obvious and the recommended range of creatinine levels for TTP was reduced and more narrow, compared with that for younger males.

LIMITATIONS, REASONS FOR CAUTION

Not including the time couples spend preparing for pregnancy before enrolment would lead to an overestimation of fecundity; additionally some couples place pregnancy plans on hold due to special emergencies, which would not have been recognized. Due to the lack of information regarding semen quality, psychological factors, sexual intercourse frequencies, and hazardous environmental factors, we could not adjust for these factors. Some variates were self-reported and dichotomized, which were prone to bias. Direct variables reflecting muscle mass and impaired kidney function were lacking. Thus, extrapolation should be done with caution.

WIDER IMPLICATIONS OF THE FINDINGS

Male creatinine is associated with couples' fecundity and the relationship varied by age. This study provides a better understanding of the potential implications and significance of different creatinine levels and their association with the clinical significance regarding couples' fecundity.

STUDY FUNDING/COMPETING INTEREST(S)

This research has received funding from the National Natural Science Foundation of China (Grant No. 81872634), the Basic Research Funds of Central Public Welfare Research Institutes of China (Grant No. 2023GJZ03), the National Key Research and Development Program of China (Grant No. 2016YFC1000307), and the Project of National Research Institute for Family Planning (Grant No. 2018NRIFPJ03), People's Republic of China. The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

The general external exposome and the development or progression of chronic kidney disease: A systematic review and meta-analyses

The impact of environmental risk factors on chronic kidney disease (CKD) remains unclear. This systematic review aims to provide an overview of the literature on the association between the general external exposome and CKD development or progression. We searched MEDLINE and EMBASE for case-control or cohort studies, that investigated the association of the general external exposome with a change in eGFR or albuminuria, diagnosis or progression of CKD, or CKD-related mortality. The risk of bias of included studies was assessed using the Newcastle-Ottawa Scale. Summary effect estimates were calculated using random-effects meta-analyses. Most of the 66 included studies focused on air pollution (n = 33), e.g. particulate matter (PM) and nitric oxides (NOx), and heavy metals (n = 21) e.g. lead and cadmium. Few studies investigated chemicals (n = 7) or built environmental factors (n = 5). No articles on other environment factors such as noise, food supply, or urbanization were found. PM2.5 exposure was associated with an increased CKD and end-stage kidney disease incidence, but not with CKD-related mortality. There was mixed evidence regarding the association of NO2 and PM10 on CKD incidence. Exposure to heavy metals might be associated with an increased risk of adverse kidney outcomes, however, evidence was inconsistent. Studies on effects of chemicals or built environment on kidney outcomes were inconclusive. In conclusion, prolonged exposure to PM2.5 is associated with an increased risk of CKD incidence and progression to kidney failure. Current studies predominantly investigate the exposure to air pollution and heavy metals, whereas chemicals and the built environment remains understudied. Substantial heterogeneity and mixed evidence were found across studies. Therefore, long-term high-quality studies are needed to elucidate the impact of exposure to chemicals or other (built) environmental factors and CKD.

Long-term ambient air pollution exposure and renal function and biomarkers of renal disease

BACKGROUND

Despite accumulating evidence of an association between air pollution and renal disease, studies on the association between long-term exposure to air pollution and renal function are still contradictory. This study aimed to investigate this association in a large population with relatively low exposure and with improved estimation of renal function as well as renal injury biomarkers.

METHODS

We performed a cross-sectional analysis in the middle-aged general population participating in the Swedish CardioPulmonary bioImaging Study (SCAPIS; n = 30 154). Individual 10-year exposure to total and locally emitted fine particulate matter (PM2.5), inhalable particulate matter (PM10), and nitrogen oxides (NOx) were modelled using high-resolution dispersion models. Linear regression models were used to estimate associations between exposures and estimated glomerular filtration rate (eGFR, combined creatinine and cystatin C) and serum levels of renal injury biomarkers (KIM-1, MCP-1, IL-6, IL-18, MMP-2, MMP-7, MMP-9, FGF-23, and uric acid), with consideration of potential confounders.

RESULTS

Median long-term PM2.5 exposure was 6.2 µg/m3. Almost all participants had a normal renal function and median eGFR was 99.2 mL/min/1.73 m2. PM2.5 exposure was associated with 1.3% (95% CI 0.6, 2.0) higher eGFR per 2.03 µg/m3 (interquartile range, IQR). PM2.5 exposure was also associated with elevated serum matrix metalloproteinase 2 (MMP-2) concentration, with 7.2% (95% CI 1.9, 12.8) higher MMP-2 per 2.03 µg/m3. There was a tendency towards an association between PM10 and higher levels of uric acid, but no associations were found with the other biomarkers. Associations with other air pollutants were null or inconsistent.

CONCLUSION

In this large general population sample at low exposure levels, we found a surprising association between PM2.5 exposure and a higher renal filtration. It seems unlikely that particle function would improve renal function. However, increased filtration is an early sign of renal injury and may be related to the relatively healthy population at comparatively low exposure levels. Furthermore, PM2.5 exposure was associated with higher serum concentrations of MMP-2, an early indicator of renal and cardiovascular pathology.

Association of air pollution with incidence of end-stage kidney disease in two large European cohorts

End-stage kidney disease (ESKD) poses a high burden on patients and health systems. While numerous studies indicate an association between air pollution and chronic kidney disease, studies on ESKD are rare. We investigated the association of long-term exposure to nitrogen dioxide (NO₂), fine particulate matter (PM2.5), black carbon (BC) and ozone (O3) with ESKD incidence in two large population-based European cohorts. We followed individuals in the Austrian Vorarlberg Health Monitoring and Promotion Program (VHM&PP) and the Italian Rome Longitudinal Study (RoLS) using dialysis and kidney transplant registries. Long-term exposure to pollutants was estimated at the home address using Europe-wide land use regression models at 100x100m scale. Hazard ratios (HR) were determined from Cox-proportional hazard models adjusted for individual and neighbourhood level confounders. We observed 501 events among 136,823 individuals in VHM&PP (mean age 42.1 years; crude incidence rate (IR) 0.14 per 1000 person-years) and 3231 events among 1,939,461 individuals in RoLS (mean age 52.4 years; IR 0.22 per 1000 person-years). In VHM&PP, there was no evidence of an association between PM2.5 or O3 and ESKD. There were elevated HRs but with large confidence intervals for BC (HR 1.17 [95 % confidence interval (CI): 0.98, 1.39] for 0.5*10-5/m), and for NO₂ (HR 1.14 [95%CI: 0.96, 1.35] for 10 μg/m3). In RoLS, ESKD was associated with PM2.5 (HR 1.37 [95 % CI: 1.06, 1.76] for an increase of 5 μg/m3), while there was no evidence of association with BC, NO2, or O3 exposure. Our study suggests an association of air pollution with ESKD incidence, which differed between the two cohorts and may possibly be influenced by respective air pollution mixtures.

Long-term exposure to air pollution and chronic kidney disease-associated mortality-Results from the pooled cohort of the European multicentre ELAPSE-study

Despite the known link between air pollution and cause-specific mortality, its relation to chronic kidney disease (CKD)-associated mortality is understudied. Therefore, we investigated the association between long-term exposure to air pollution and CKD-related mortality in a large multicentre population-based European cohort. Cohort data were linked to local mortality registry data. CKD-death was defined as ICD10 codes N18-N19 or corresponding ICD9 codes. Mean annual exposure at participant's home address was determined with fine spatial resolution exposure models for nitrogen dioxide (NO2), black carbon (BC), ozone (O3), particulate matter ≤2.5 μm (PM2.5) and several elemental constituents of PM2.5. Cox regression models were adjusted for age, sex, cohort, calendar year of recruitment, smoking status, marital status, employment status and neighbourhood mean income. Over a mean follow-up time of 20.4 years, 313 of 289,564 persons died from CKD. Associations were positive for PM2.5 (hazard ratio (HR) with 95% confidence interval (CI) of 1.31 (1.03-1.66) per 5 μg/m3, BC (1.26 (1.03-1.53) per 0.5 × 10- 5/m), NO2 (1.13 (0.93-1.38) per 10 μg/m3) and inverse for O3 (0.71 (0.54-0.93) per 10 μg/m3). Results were robust to further covariate adjustment. Exclusion of the largest sub-cohort contributing 226 cases, led to null associations. Among the elemental constituents, Cu, Fe, K, Ni, S and Zn, representing different sources including traffic, biomass and oil burning and secondary pollutants, were associated with CKD-related mortality. In conclusion, our results suggest an association between air pollution from different sources and CKD-related mortality.

Long-term exposure to fine particulate matter constituents in relation to chronic kidney disease: evidence from a large population-based study in China

The effects of long-term exposure to fine particulate matter (PM2.5) constituents on chronic kidney disease (CKD) are not fully known. This study sought to examine the association between long-term exposure to major PM2.5 constituents and CKD and look for potential constituents contributing substantially to CKD. This study included 81,137 adults from the 2018 to 2019 baseline survey of China Multi-Ethnic Cohort. CKD was defined by the estimated glomerular filtration rate. Exposure concentration data of 7 major PM2.5 constituents were assessed by satellite remote sensing. Logistic regression models were used to estimate the effect of each PM2.5 constituent exposure on CKD. The weighted quantile sum regression was used to estimate the effect of mixed exposure to all constituents. PM2.5 constituents had positive correlations with CKD (per standard deviation increase), with ORs (95% CIs) of 1.20 (1.02-1.41) for black carbon, 1.27 (1.07-1.51) for ammonium, 1.29 (1.08-1.55) for nitrate, 1.20 (1.01-1.43) for organic matter, 1.25 (1.06-1.46) for sulfate, 1.30 (1.11-1.54) for soil particles, and 1.63 (1.39-1.91) for sea salt. Mixed exposure to all constituents was positively associated with CKD (1.68, 1.32-2.11). Sea salt was the constituent with the largest weight (0.36), which suggested its importance in the PM2.5-CKD association, followed by nitrate (0.32), organic matter (0.18), soil particles (0.10), ammonium (0.03), BC (0.01). Sulfate had the least weight (< 0.01). Long-term exposure to PM2.5 sea salt and nitrate may contribute more than other constituents in increasing CKD risk, providing new evidence and insights for PM2.5-CKD mechanism research and air pollution control strategy.

Ambient particulate matter and renal function decline in people with HIV/AIDS

OBJECTIVE

We aimed to explore the effect of particulate matter exposure on renal function in people with HIV/AIDS (PWHA).

METHODS

A total of 37 739 repeated measurements were conducted on eGFR levels, serum creatinine (Scr), and the triglyceride-glucose (TyG) index in 6958 PWHAs. The relationship between 1 and 28 day moving averages of particulate matter concentrations with Scr and eGFR was assessed using linear mixed-effects models. Modified Poisson regression models were employed to assess the associations of cumulative particulate matter exposure with the incidence of chronic kidney disease (CKD). Mediation analyses were used to examine the role of TyG index.

RESULTS

Short-term exposure to particulate matter was related to reduced renal function. The strongest associations between exposure to particulate matter (PM) 1 , PM 2.5 , and PM 10 and percentage changes in eGFR were observed at 7-day moving average exposure windows, with a respective decrease of 0.697% (-1.008%, -0.386%), 0.429% (-0.637%, -0.220%), and 0.373% (-0.581%, -0.164%) per IQR increment. Long-term exposure to PM 1 , PM 2.5 , and PM 10 was positively linked with the incidence of CKD, with each IQR increment corresponding to fully adjusted RRs (95% CIs) of 1.631 (1.446-1.839), 1.599 (1.431-1.787), and 1.903 (1.665-2.175), respectively. TyG index-mediated 8.87, 8.88, and 7.58% of the relationship between cumulative exposure to PM 1 , PM 2.5 , and PM 10 and increased risk of CKD, respectively.

CONCLUSION

Exposure to particulate matter among PWHAs is linked to reduced renal function, potentially contributing to increased CKD incidence, where the TyG index might serve as a partial mediator.

Ambient black carbon reaches the kidneys

BACKGROUND

Ultrafine particles, including black carbon (BC), can reach the systemic circulation and therefore may distribute to distant organs upon inhalation. The kidneys may be particularly vulnerable to the adverse effects of BC exposure due to their filtration function.

OBJECTIVES

We hypothesized that BC particles reach the kidneys via the systemic circulation, where the particles may reside in structural components of kidney tissue and impair kidney function.

METHODS

In kidney biopsies from 25 transplant patients, we visualized BC particles using white light generation under femtosecond-pulsed illumination. The presence of urinary kidney injury molecule-1 (KIM-1) and cystatin c (CysC) were evaluated with ELISA. We assessed the association between internal and external exposure matrices and urinary biomarkers using Pearson correlation and linear regression models.

RESULTS

BC particles could be identified in all biopsy samples with a geometric mean (5th, 95th percentile) of 1.80 × 103 (3.65 × 102, 7.50 × 103) particles/mm3 kidney tissue, predominantly observed in the interstitium (100 %) and tubules (80 %), followed by the blood vessels and capillaries (40 %), and the glomerulus (24 %). Independent from covariates and potential confounders, we found that each 10 % higher tissue BC load resulted in 8.24 % (p = 0.03) higher urinary KIM-1. In addition, residential proximity to a major road was inversely associated with urinary CysC (+10 % distance: -4.68 %; p = 0.01) and KIM-1 (+10 % distance: -3.99 %; p < 0.01). Other urinary biomarkers, e.g., the estimated glomerular filtration rate or creatinine clearance showed no significant associations.

DISCUSSION AND CONCLUSION

Our findings that BC particles accumulate near different structural components of the kidney represent a potential mechanism explaining the detrimental effects of particle air pollution exposure on kidney function. Furthermore, urinary KIM-1 and CysC show potential as air pollution-induced kidney injury biomarkers for taking a first step in addressing the adverse effects BC might exert on kidney function.

Cross-sectional study of household solid fuel use and renal function in older adults in China

BACKGROUND

Emerging evidence links outdoor air pollution and declined renal function but the relationship between household air pollution and renal function is not well understood.

METHODS

Using cross-sectional data from the multi-provincial INTERMAP-China Prospective Study, we collected blood samples and questionnaire information on stove use and socio-demographic factors. We calculated estimated glomerular filtration rate (eGFR) from serum creatinine to assess renal function. Participants with eGFR <60 mL/min per 1.73 m2 were defined as having chronic kidney disease (CKD) in this analysis. Generalized estimating equations were used to estimate the association of household fuel with renal function and prevalent CKD in models adjusting for confounders.

RESULTS

Among the 646 enrolled adults (40-79y; 56% female), one-third exclusively used clean fuel (gas and electric) cookstoves and 11% of northern China participants (n = 49 of 434) used only clean fuel heaters, whereas the rest used solid fuel. In multivariable models, use of solid fuel cookstoves was associated with 0.17 ml/min/1.73 m2 (95% CI: -0.30, 0.64) higher eGFR and 19% (0.86, 1.64) higher prevalence of CKD than exclusive clean fuel use. Greater intensity of solid fuel use was associated with 0.25 ml/min/1.73 m2 (-0.71, 0.21) lower eGFR per 5 stove-use years, though the confidence intervals included the null, while greater current intensity of indoor solid fuel use was associated with 1.02 (1.00, 1.04) higher prevalent CKD per 100 stove-use days per year. Larger associations between current solid fuel use and intensity of use with lower eGFR and prevalent CKD were observed among participants in southern China, those with hypertension or diabetes (eGFR only), and females (CKD only), through these groups had small sample sizes and some confidence intervals included the null.

CONCLUSION

We found inconsistent evidence associating household solid fuel use and renal function in this cross-sectional study of peri-urban Chinese adults.

Adverse Effects of fine particulate matter on human kidney functioning: a systematic review

BACKGROUND

Ambient fine particulate matter (PM < 2.5 μm, PM2.5) is gaining increasing attention as an environmental risk factor for health. The kidneys are considered a particularly vulnerable target to the toxic effects that PM2.5 exerts. Alteration of kidney function may lead to a disrupted homeostasis, affecting disparate tissues in the body. This review intends to summarize all relevant knowledge published between January 2000 and December 2021 on the effects of ambient PM2.5 and the adverse effects on kidney function in adults (≥ 18 years).

RESULTS AND DISCUSSION

Studies published in peer-reviewed journals, written in English, regarding the effects of PM2.5 on kidney function and the development and/or exacerbation of kidney disease(s) were included. Of the 587 nonduplicate studies evaluated, 40 were included, comprising of studies on healthy or diagnosed with pre-existing disease (sub)populations. Most of the studies were cohort studies (n = 27), followed by 10 cross-sectional, 1 ecological and 2 time-series studies. One longitudinal study was considered intermediate risk of bias, the other included studies were considered low risk of bias. A large portion of the studies (n = 36) showed that PM2.5 exposure worsened kidney outcome(s) investigated; however, some studies show contradictory results. Measurement of the estimated glomerular filtration rate, for instance, was found to be positively associated (n = 8) as well as negatively associated (n = 4) with PM2.5.

LIMITATIONS AND CONCLUSION

The main limitations of the included studies include residual confounding (e.g., smoking) and lack of individual exposure levels. The majority of included studies focused on specific subpopulations, which may limit generalizability. Evidence of the detrimental effects that ambient PM2.5 may exert on kidney function is emerging. However, further investigations are required to determine how and to what extent air pollution, specifically PM2.5, exerts adverse effects on the kidney and alters its function.

REGISTRATION

The systematic review protocol was submitted and published by the International Prospective Register of Systematic Reviews (PROSPERO; CRD42020175615 ).