Association of meteorological factors and ambient air pollution on medical care utilization for urolithiasis: a population-based time-series study

Cross ethnic Mendelian randomization analysis reveals causal relationship between air pollution and risk of kidney stones

Accumulating evidence has indicated that exposures to air pollution increase the odds of kidney stones. However, the previous research methods were limited. To address this gap, we employed genome-wide association studies (GWAS) datasets and Mendelian randomization (MR) to verify the causation. Applying publicly accessible summary datasets from UK Biobank, FinnGen consortium and Biobank Japan, a two-sample MR, and further multivariate MR were carried out to calculate the causality between air pollution [particulate matter 2.5 (PM2.5), PM2.5 absorbance, PM2.5-10, PM10, nitrogen dioxide, and nitrogen oxides] and kidney stone risk in three different populations (European, East Asian, and South Asian). The inverse variance weighted (IVW) was utilized for its first-step assessment, supplemented with MR-Egger, weighted median, Cochran's Q test, MR-Egger intercept and leave-one-out analysis to ensure the robustness. Employing IVW, we discovered in the European population that PM2.5 absorbance was statistically correlated with kidney stone risk (odds ratio (OR) = 1.40; 95% confidence interval (CI), 1.01-1.94; P = 0.04), with no heterogeneity, pleiotropy, or sensitivity observed. Additionally, the MVMR result revealed the directly causative connection between a single PM2.5 absorbance and the increase in kidney stone risk (OR = 1.77, 95%CI: 1.06-2.98, p = 0.03). Our investigation proposed the correlation between PM2.5 absorbance and an increased risk of kidney stones in European populations. The control of air pollution, especially PM2.5, may have crucial implications for the prevention of kidney stones.

Environmental determinants in the development of kidney stone

The increase with years of kidney stone prevalence has become a serious public health problem worldwide. The geographical distribution pattern of kidney stone (known as "stone belt") clearly indicates the critical role of environmental exposure in its formation, which has long been an underestimated risk factor in studying the development of kidney stone. Based on our previous studies and bibliometric analysis, we discerned four environmental determinants and elaborated their impacts on human internal exposure related to kidney stone formation. The importance of climatic factor lies in that the relatively high temperature and low humidity environment may contribute greater prevalence of kidney stone, since it promotes elevating the concentration of relatively insoluble stone-forming salts. Geological factors including water quality, hydrogeology, and soil environment is involved in kidney stone formation via the food chain. Additionally, air pollution and heavy metal pollutants also act as potential risk factors by directly or indirectly affecting the normal renal function and urinary metabolism. This review thus provides insights into the specific mechanisms affecting metabolic changes in the human body which result in kidney stone formation under environmental exposure, and shed light on the pathogenesis of nephrolithiasis from an interdisciplinary perspective.

Association analysis of dry heat or wet cold weather and the risk of urolithiasis hospitalization in a southern Chinese city

To analyze the relationship between hot or cold, and wet or dry interacting weather, and urolithiasis-related hospitalizations. Distributed lag nonlinear model for time series design was used to build exposure-response curves for the association of daily mean temperature and relative humidity with urolithiasis-related hospitalizations. Cut-off values were determined for temperature, humidity, and dichotomous categories to define heat-cold and wet-dry meteorological conditions. Based on a total of 38,184 urolithiasis-related hospitalizations from 2018 to 2019 in Ganzhou as a large prefecture-level city in southern China, dry-heat weather during the hot season (May to September) increased the risk of urolithiasis-related hospitalizations (relative risk [RR]: 1.17, 95% confidence interval [CI]: 1.02, 1.35), with the most pronounced effects in those aged 21-40 years and male. Wet-cold weather in the cold season (December to February) increased the risk of urolithiasis-related hospitalizations in the total population (RR: 1.58, 95% CI: 1.20, 2.07). The effect was significant in the 21-60 years old age and both genders groups. Both dry-heat weather in the hot season and wet-cold weather in the cold season could trigger urolithiasis.

Association between ambient temperature and hospitalizations for urolithiasis in four counties of Ganzhou, China

We collected meteorological and urolithiasis-related hospitalization data from four counties in Ganzhou City for 2018-2019 and used the DLNM method to assess the lagged and cumulative effects of temperature on urolithiasis hospitalizations and obtain the total effect after meta-combination. Based on the nonlinear association between temperature and urolithiasis hospitalizations, the relative risk of overall high temperature (30℃) was 2.10 (95% CI: 1.07-4.10). No statistically significant difference (p = 0.07) was observed between males (RR = 2.04, 95% CI: 1.42-2.94) and females (RR = 1.45, 95% CI: 1.09-1.92) for the heat effect, which was higher in the ≥ 60 years age group (RR = 3.18, 95% CI: 1.76-5.76) than in the < 60 years age group (p = 0.007). High temperatures increased the risk of hospitalization for urolithiasis in Ganzhou, China, and the risk was greatest for individuals aged 60 and above, with similar risks observed across counties and genders.

Air pollutants, residential greenspace, and the risk of kidney stone disease: a large prospective cohort study from the UK Biobank

BACKGROUND

The epidemiological evidence regarding the correlation between air pollution, residential greenspace, and the risk of kidney stone disease (KSD) is limited, with no large-scale prospective studies conducted on this relationship.

OBJECTIVE

We conducted a large-scale prospective study from the UK Biobank to explore the correlation between air pollution, residential greenspace, and the risk of KSD.

METHODS

This study included 419,835 UK Biobank participants who did not have KSD at baseline. An air pollution score was derived through the summation of concentrations for five air pollutants, including particulate matter (PM) with aerodynamic diameter ≤2.5 μm (PM2.5), ranging from 2.5 to 10 μm (PM2.5-10), ≤10 μm (PM10), nitrogen dioxide (NO2), and nitrogen oxides (NOx). Various covariates were adjusted for in Cox proportional hazard regression to evaluate the risk of KSD associated with air pollution score, single air pollutant, and residential greenspace.

RESULTS

During a follow-up period of 12.7 years, 4503 cases of KSD were diagnosed. Significant associations were found between KSD risk and air pollution score (HR: 1.08, 95% CI: 1.03-1.13), PM2.5 (1.06, 1.02-1.11), PM10 (1.04, 1.01-1.07), NO2 (1.09, 1.02-1.16), NOx (1.08, 1.02-1.11), greenspace buffered at 300 m (0.95, 0.91-0.99), and greenspace buffered at 1000 m (0.92, 0.86-0.98) increase per interquartile range (IQR). PM2.5 and NO2 reductions may be a key mechanism for the protective impact of residential greenspace on KSD (P for indirect path < 0.05).

IMPACT

Prolonged exposure to air pollution was correlated with a higher risk of KSD, while residential greenspace exhibits an inverse association with KSD risk, partially mediated by the reduction in air pollutants concentrations. These findings emphasize the significance of mitigating air pollution and maintaining substantial greenspace exposure as preventive measures against KSD.

High ambient temperature impact on the pattern of emergency-room visits due to renal colic in the Middle East

Urolithiasis has a seasonal pattern, with an established increase in incidence during the summer months. This study aims to assess the impact of high ambient temperatures on emergency room (ER) visits related to renal colic (RC) in a Middle Eastern country over the past decade. Population data were extracted using the MDClone Big Data platform. We recorded demographic and clinical data on all RC-associated ER visits from January 2012 to April 2023 and calculated the heat index (HI) that combines daily average coastal plane temperatures and humidity percentages. There was a total of 12,770 ER visits (median age 48 years, 9,236 (72%) males). The number of visits increased during the hottest months (July-October), with the highest numbers recorded during August. The number of visits remained stable throughout the study. We identified a linear association between humidity and the incidence of ER visits (p = 0.002), and a non-linear association between ambient temperature (p < 0.0001) and HI (p < 0.0001). There was a direct relationship between high temperatures and ER visits on the same day (risk ratio [RR]: 1.75, p = 0.036), with a 2-day lag (RR: 1.123, p = 0.024). In Conclusion, there is a significant relationship between temperature, humidity, HI, and the number of ER visits due to RC. Adjusted resource allocation and healthcare workforce availability are essential for managing additional cases during heat waves. Clinical implications: Increased demand is expected during heatwaves and within a 2-day lag, emphasizing the importance of proactive strategies to effectively manage RC patients.

Positive association between ambient air pollutants and incident kidney stones

We aimed to assess the association between exposure to various air pollutants, individually or jointly, and incident kidney stones, and examine whether genetic susceptibility for kidney stones may modify this association. 453,977 participants without prior kidney stones from the UK Biobank were included. Annual mean concentrations of PM2.5, PM2.5-10, PM10, NO2, and NOx were estimated with a land use regression model. A weighted air pollution score was constructed that incorporates the five pollutants mentioned above. A genetic risk score (GRS) was calculated based on 20 single-nucleotide polymorphisms associated with kidney stones. The primary outcome was incident kidney stones. During a median follow-up of 11.9 years, 5,375 kidney stones were recorded. The adjusted HRs (95%CI) of incident kidney stones were 1.04 (1.01-1.07), 1.02 (1.00-1.05), 1.03 (1.01-1.06), 1.05 (1.02-1.08), and 1.04 (1.01-1.07), for per standard deviation (SD) increment in PM2.5 (SD:1.06 μg/m3), PM2.5-10 (SD:0.90 μg/m3), PM10 (SD:1.90 μg/m3), NO2 (SD:7.63 μg/m3), and NOx (SD: 15.63 μg/m3), respectively. Moreover, there was a significantly linear association between the air pollution score and incident kidney stones (per SD increment: HR, 1.05, 95%CI: 1.02-1.08), especially in those without diabetes (vs. participants with diabetes; P-interaction = 0.037). In addition, the association between air pollution and kidney stones was statistically significant only in participants within intermediate-high kidney stone GRS, but not in those with low GRS kidney stone, though the interaction was not significant (P-interaction = 0.385). In conclusion, exposure to air pollution was associated with a higher risk of incident kidney stones, calling for the need to improve air quality.

Associations between short-term exposure to PM2.5, NO2 and O3 pollution and kidney-related conditions and the role of temperature-adjustment specification: A case-crossover study in New York state

Epidemiologic evidence on the relationship between air pollution and kidney disease remains inconclusive. We evaluated associations between short-term exposure to PM_2.5, NO₂ and O₃ and unplanned hospital visits for seven kidney-related conditions (acute kidney failure [AKF], urolithiasis, glomerular diseases [GD], renal tubulo-interstitial diseases, chronic kidney disease, dysnatremia, and volume depletion; n = 1,209,934) in New York State (2007-2016). We applied a case-crossover design with conditional logistic regression, controlling for temperature, dew point temperature, wind speed, and solar radiation. We used a three-pollutant model at lag 0-5 days of exposure as our main model. We also assessed the influence of model adjustment using different specifications of temperature by comparing seven temperature metrics (e.g., dry-bulb temperature, heat index) and five intraday temperature measures (e.g., daily mean, daily minimum, nighttime mean), according to model performance and association magnitudes between air pollutants and kidney-related conditions. In our main models, we adjusted for daytime mean outdoor wet-bulb globe temperature, which showed good model performance across all kidney-related conditions. We observed the odds ratios (ORs) for 5 μg/m³ increase in daily mean PM_2.5 to be 1.013 (95% confidence interval [CI]: 1.001, 1.025) for AKF, 1.107 (95% CI: 1.018, 1.203) for GD, and 1.027 (95% CI: 1.015, 1.038) for volume depletion; and the OR for 5 ppb increase in daily 1-hour maximum NO₂ to be 1.014 (95% CI; 1.008, 1.021) for AKF. We observed no associations with daily 8-hour maximum O₃ exposure. Association estimates varied by adjustment for different intraday temperature measures: estimates adjusted for measures with poorer model performance resulted in the greatest deviation from estimates adjusted for daytime mean, especially for AKF and volume depletion. Our findings indicate that short-term exposure to PM_2.5 and NO₂ is a risk factor for specific kidney-related conditions and underscore the need for careful adjustment of temperature in air pollution epidemiologic studies.

The influence of climatic factors in the seasonal fluctuation of urolithiasis and the trend of stone disease management in the southern Taiwan

This study aims to analyze the effects of climate parameters on the number of urolithiasis treatments in our hospital and understand the effects of climate parameters on the prevalence of urolithiasis in southern Taiwan. We also look at trends associated with urolithiasis and treatments. Retrospectively reviewed the records of extracorporeal shockwave lithotripsy (ESWL), ureteroscopy (URS), retrograde intrarenal surgery (RIRS), and percutaneous nephrolithotripsy (PCNL) performed in our hospital from January 2012 to December 2018. Climate data for were collected from Central Weather Bureau. The monthly meteorological data included average temperatures, humidity, rainfall, sunshine hours, atmospheric pressure, and wind speed. Monthly numbers of patients undergoing stone management was positively correlated to average temperature (r = 0.657), relative humidity (r = 0.234), monthly rainfall (r = 0.261) and monthly sunshine hours (r = 0.348), while it was negatively correlated to atmospheric pressure (r = - 0.522). The multivariate linear regression model demonstrated temperature (ß = 10.682, 95% CI 6.178-14.646, p < 0.001) and Relative humidity (ß = - 95% CI - 5.233- - 1.216, p = 0.002) to be independently related to numbers of stone treatment. The data also revealed a rising prevalence of urolithiasis with an associated increase in the number of interventions, with fewer ESWL (74.0-49.4%). Temperature and relative humidity are associated with monthly numbers of stone treatment. Ambient temperature is the most critical climate factor affecting the prevalence of symptomatic urolithiasis and intention of active stone removal in southern Taiwan.

Short-term effects of ambient air pollution on emergency department visits for urolithiasis: A time-series study in Wuhan, China

Background

Previous studies have explored the correlation between short-term exposure to air pollution and urinary system diseases, but lack of evidence on the correlation between air pollution and urolithiasis.

Methods

Daily data of emergency department visits (EDVs), concentrations of six air pollutants (SO₂, NO₂, PM_2.5, PM₁₀, CO, and O₃) and meteorological variables were collected in Wuhan, China, from 2016 to 2018. And a time-series study was conducted to investigate short-term effects of air pollutants on urolithiasis EDVs. In addition, stratified analyses by season, age and gender were also conducted.

Results

A total of 7,483 urolithiasis EDVs were included during the study period. A 10-μg/m³ increase of SO₂, NO₂, PM_2.5, CO, PM₁₀, and O₃ corresponded to 15.02% (95% confidence interval [CI]: 1.69%, 30.11%), 1.96% (95% CI: 0.19%, 3.76%), 1.09% (95% CI:-0.24%, 2.43%), 0.14% (95% CI: 0.02%, 0.26%), 0.72% (95% CI: 0.02%, 1.43%), and 1.17% (95% CI: 0.40%, 1.94%) increases in daily urolithiasis EDVs. Significant positive correlations were observed between SO₂, NO₂, CO, and O₃ and urolithiasis EDVs. The correlations were mainly among females (especially PM_2.5 and CO) and younger people (especially SO₂, NO₂, and PM₁₀) but the effect of CO was more obvious in elders. Furthermore, the effects of SO₂ and CO were stronger in warm seasons, while the effects of NO₂ were stronger in cool seasons.

Conclusion

Our time-series study indicates that short-term exposure to air pollution (especially SO₂, NO₂, CO, and O₃) was positively correlated with EDVs for urolithiasis in Wuhan, China, and the effects varied by season, age and gender.