Body fatness, diabetes, physical activity and risk of kidney stones: a systematic review and meta-analysis of cohort studies

2bRAD-M Reveals the Characteristics of Urinary Microbiota in Overweight Patients with Urinary Tract Stones

Background: Urinary tract stone (UTS) is a common disease significantly impacting human health. Obesity influences stone formation and increases UTS incidence, yet the differences in the urinary microbiota and pathways between overweight and healthy-weight UTS patients remain unclear. Methods: In this study, 16 patients were analyzed: 8 overweight and 8 healthy-weight UTS patients. Bladder urine samples were collected during surgery, and DNA was extracted for microbial analysis using 2bRAD markers. Microbial diversity and KEGG pathway differences were studied. Results: The results showed that overweight UTS patients had a significantly higher urinary microbial diversity than healthy-weight patients. The analysis identified differences in microbiota at various taxonomic levels. LEfSe analysis revealed Sphingomonas_paucimobilis as abundant in overweight patients, while Bifidobacterium_piotii dominated in healthy-weight patients. Key species, including Ralstonia_sp000620465, Sphingomonas_paucimobilis, and Campylobacter_D_coli, were identified. KEGG analysis highlighted enriched pathways in overweight UTS patients, including the porphyrin and chlorophyll metabolism, fatty acid metabolism, amino acid degradation, and renin-angiotensin and mineral absorption pathways. Conclusions: This study is the first to use 2bRAD-M microbiome analysis to compare the urinary microbiota between overweight and healthy-weight UTS patients. It identified significant microbiota and pathway differences, suggesting a link between microbiota imbalance, obesity, and stone formation. These findings provide potential targets for further research on obesity-related stone susceptibility mechanisms.

Obesity and BMI score as risk factors for urolithiasis: a systematic review over 30 years

PURPOSE OF REVIEW

To examine association between high BMI, obesity, and kidney stone disease (KSD). For this, systematic review of empirical studies was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA) guidelines. Cochrane Library, EMBASE, MEDLINE, CINAHL, AMED, Emcare, Clinicaltrials.gov, and WHO ICTRP were searched for English language population-based studies published from inception to October 2024, including adults aged at least 18 years reporting on high BMI, obesity and overweight, with incidence of KSD.

RECENT FINDINGS

The search identified 943 records, of which 15 relevant articles with 97 645 participants and 17 158 cases in total were enrolled in the narrative synthesis. A high heterogeneity and imbalance were observed among baseline distribution of cohorts in most studies. Thirteen studies provided comparative data on stone occurrence in obese and nonobese participants, and on per-patient analysis, three studies demonstrated a lower risk (RR < 1; 95% CI: 0.78-1.03), four studies a higher risk (RR>1; 95% CI: 0.77-2.32), and six studies depicted similar risk (RR = 1; 95% CI: 0.94-1.06) of stone occurrence between the two cohorts.

SUMMARY

Evidence in this study suggests an association between high BMI, being overweight, obesity, and increased risk of developing kidney stone disease. In the context of optimizing treatment, KSD should be considered a metabolic disease, with treatment to include dietary regimes, exercise intervention alongside pharmacotherapy to help reduce renal stone disease recurrence risk, alongside managing associated chronic diseases such as hypertension, type 2 diabetes mellitus, and coronary artery disease.

Development of an Alginate Gel Composite with Antibacterial Properties Capable of Binding Calcium-Based Residual Stone Fragments in Endoscopic Stone Surgery

Background: Complete removal of urinary stones remains a challenge, as residual fragments can contribute to recurrence and postoperative urinary tract infections. This study presents an initial laboratory investigation into the development of an alginate gel composite designed to bind calcium-based stone remnants and exhibit antibacterial properties. Methods: To evaluate gel formation, calcium oxalate powder reagent and sodium alginate (SA) powder reagent were mixed in a Becker glass and stirred on a hot plate. Stones from 17 patients who underwent stone surgery were crushed, and gel formation was confirmed using the same experimental conditions with SA powder reagent. A gel composite material containing silver nitrate and vancomycin was prepared, and antibacterial activity against Staphylococcus aureus and Escherichia coli was tested over a 5-minute period. A mixture of 0.5 g alginic acid and 0.05 g calcium oxalate monohydrate powder reagent with 50 mL distilled water formed a gel after 30 minutes. Results: Sandy stones composed of calcium oxalate formed a better gel composite when mixed with SA than those composed of uric acid. In the antibacterial test of the alginate gel composite containing silver nitrate and vancomycin against S. aureus and E. coli, the number of live bacteria in the control and alginate gel composite was 3.5 × 103 and <10, respectively. Conclusion: This study represents a preliminary laboratory investigation into the development of an alginate gel composite for potential use in urinary stone management. Further preclinical studies are necessary to evaluate its efficacy and safety before clinical translation.

Healthy dietary patterns, biological aging, and kidney stones: evidence from NHANES 2007-2018

Background

This study aims to investigate the comprehensive association between healthy dietary patterns, biological aging, and kidney stones in a large population-based cohort.

Methods

We analyzed data from 6 cycles of NHANES surveys from 2007 to 2018 and included a total of 26,755 participants. The association was examined using logistic regression, restricted cubic splines, and a mediation model. Machine learning with Shapley Additive Explanations (SHAP) was used to determine the relative importance of dietary factors. Sensitivity analysis was conducted to validate the stability of the results.

Results

A higher healthy dietary score was significantly associated with a reduced risk of kidney stone prevalence, as indicated by the Alternative Healthy Eating Index (AHEI) (OR = 0.76, 95% CI 0.69-0.84), the Dietary Approaches to Stop Hypertension Index (DASHI) (OR = 0.67, 95% CI 0.58-0.77), the Healthy Eating Index 2020 (HEI-2020) (OR = 0.80, 95% CI 0.72-0.89), and the Mediterranean Diet Index (MEDI) (OR = 0.81, 95% CI 0.73-0.89). Conversely, higher aging indicators were associated with an increased risk of kidney stones, including the following: Klemera-Doubal Method Age (KDMAge) (OR = 2.40, 95% CI 1.70-3.37) and Phenotypic Age (PhenoAge) (OR = 2.36, 95% CI 1.75-3.19). Mediation analyses suggested that aging indicators significantly mediated the relationship between healthy dietary patterns and kidney stones. Machine learning with SHAP revealed the relative importance of dietary patterns and specific dietary components in this association. The sensitivity analysis was largely consistent with the primary analyses.

Conclusion

These findings provide valuable insights into the complex interplay between dietary patterns, biological aging, and the risk of kidney stone. Promoting healthy dietary patterns may be an effective strategy for kidney stone prevention, potentially through the modulation of biological aging processes.

Association between life's crucial 9 and kidney stones: a population-based study

Purpose

This study examined the association between the Life's Crucial 9 (LC9) score and kidney stone prevalence in U.S. adults.

Methods

Using data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2014, this cross-sectional analysis focused on adult participants with kidney stone onset or recurrence. LC9 scores were divided into four quartiles for analysis. Weighted multivariable logistic regression, restricted cubic spline (RCS) modeling, threshold effect analysis, and subgroup analyses were employed to evaluate the relationship between LC9 scores and kidney stone prevalence.

Results

The study included 24,669 participants with an average age of 46.05 ± 0.34 years and a mean LC9 score of 73.76 ± 0.25. The overall prevalence of kidney stones was 8.45%, while the average recurrence rate stood at 2.96%. Importantly, for each one-point increase in the LC9 score, the incidence of kidney stones dropped by 1.2% (95% CI: 0.979 to 0.997, p = 0.014). Compared to the lowest quartile (Q1), the Q4 group exhibited a 0.305-fold higher recurrence rate (95% CI: 0.159 to 0.586, p < 0.001). Interaction analysis showed that race and gout significantly influenced the relationship between the LC9 score and kidney stone risk. Additionally, curve fitting and threshold effect analysis demonstrated a nonlinear association between LC9 scores and kidney stone recurrence, with a breakpoint identified at 72.777.

Conclusion

An elevated LC9 score correlates with a lower risk of both kidney stone formation and recurrence. Maintaining an optimal LC9 score could be an effective approach for preventing kidney stones.

Association between Two Cardiovascular Health Algorithms and Kidney Stones: A Nationwide Cross-sectional Study

Background and objective

There is limited literature on the relationship between cardiovascular health (CVH) and kidney stones. This study aims to compare the association of Life's Simple 7 (LS7) and Life's Essential 8 (LE8) with kidney stone prevalence.

Methods

A cross-sectional analysis was conducted utilizing NHANES data (2007-2018). Participants aged ≥20 yr with a history of kidney stones and available LS7 and LE8 scores were included. Both LS7 and LE8 are scored such that higher scores indicate better CVH. Weighted proportions and multivariable logistic regression models assessed the relationship between CVH metrics and kidney stone prevalence, adjusting for confounders. The receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) were determined to distinguish between LS7 and LE8 in terms of their discriminative ability within the model associated with kidney stones.

Key findings and limitations

A total of 23 563 adults were included; the mean age was 48.1 yr (48.1% male). Kidney stone prevalence was 10.1%. The mean LS7 and LE8 scores were 8.4 and 68.6, respectively. A multivariate analysis and the restricted cubic spline model indicated a significant nonlinear negative correlation between these CVH measures and kidney stone prevalence. The LS7 ideal group showed a lower prevalence than the poor group (odds ratio [OR] = 0.53; 95% confidence interval [CI] 0.41-0.69). The high CVH group had a lower prevalence than the low CVH group (OR = 0.46; 95% CI 0.36-0.57). The AUCs for evaluating LS7 and kidney stones, as well as for LE8 and kidney stones were 0.676 and 0.677, respectively. Limitations were as follows: cross-sectional design limiting causal inference, recall bias from self-reported data, and potential residual confounding.

Conclusions and clinical implications

Both CVH algorithms show a significant nonlinear negative correlation with kidney stone prevalence. LS7 may be more accessible for broader implementation. Further high-quality prospective studies are needed to clarify this relationship.

Patient summary

In this study, we explored the connection between heart health and kidney stones using data from a large national survey. We found that better heart health, measured by two different scoring methods, is linked to a lower chance of having kidney stones. Our results suggest that promoting heart health could help reduce the risk of kidney stones in adults.

Kidney stone and risk of cardiovascular diseases: a cross-sectional study in the southeast of Iran

BACKGROUND

Since the prevalence of kidney stones and cardiovascular diseases (CVD) is increasing globally and also in Iran, it is vital to assess the associations between both disorders. The current study aimed to investigate the association between kidney stones and the risk of CVD.

METHODS

This study was cross-sectional in design, which used the data of the Rafsanjan cohort study (RCS), a population-based Prospective epidemiological research study in Iran (PERSIAN) that recruited 10,000 participants of both genders aged 35-70 years from four urban and suburban areas of Rafsanjan. Demographic factors, medical history, personal habits, biochemical parameters including Fasting blood sugar (FBS), glomerular filtration rate (GFR), creatine (Cr), Blood urea nitrogen (BUN), urine specific gravity (USG), and lipids of the participants were collected according to standard protocols.

RESULTS

The results showed that the risk of CVD was higher in men (51.02%) than in women (48.98%). Also, the results showed the highest risk of CVD development for age ≥ 56 years old. The results were presented in about 31% of patients with kidney stones, 19.5% of patients with abnormal urine tests, 9.84% with Proteinuria, more than 33% with abnormal USG, and more than 94% of patients with abnormal GFR had CVD. The odds of CVD were increased in patients with kidney stones (22%), female (25%), and age ≥ 56 years old (24%).

CONCLUSIONS

There was a high prevalence of kidney stones and CVD risk factors, such as gender, age, and kidney stones that increased the risk of cardiovascular disease.

Prevalence and Factors Associated with Kidney Stones in the Elderly Iranian Population: Findings from the Ardakan Cohort Study on Aging (ACSA)

BACKGROUND

The incidence of kidney stones has been rising globally, particularly among the elderly. This study aims to determine the prevalence of kidney stones and its associated factors in Iran.

METHODS

This cross-sectional study was conducted using the data collected in the first phase of Ardakan Cohort Study on individuals aged 50 years and above, in the Yazd province, Iran. Baseline data was collected using a comprehensive checklist and kidney stone occurrence was ascertained through participants' self-reported response to the question "Have you ever been diagnosed with kidney stones?" Logistic regression analysis was used due to the binary nature of the outcome.

RESULTS

Period prevalence of kidney stone was 22.79 (95% CI=19.41 to 24.12). Thus, out of the total sample of 4,884 individuals, 1113 participants had a history of kidney stones. Among these, 412 (37%) were female and 701 (63%) were male. Significant associations were observed between a history of kidney stones and factors such as self-reported poor health, alcohol consumption, dysuria, higher education level, male gender, and presence of calcium oxalate crystals.

CONCLUSION

This study shows the high prevalence of kidney stones compared to other studies. Considering the relationship between kidney stones and some preventable disorders in the elderly, such as high blood pressure and alcohol consumption, it seems that paying attention to kidney stone disorders can be part of preventive health and treatment interventions for this population group.

Prospective study investigating the influence of nutritional intervention on biochemical profiles in patients with recurrent urolithiasis

BACKGROUND AND OBJECTIVES

Urolithiasis, commonly known as kidney stones, is a condition significantly impacted by dietary habits. The objective of this study is to evaluate the impact of a tailored dietary plan on the crystalluria and biological parameters of patients with different types of kidney stones over a 3-month period.

METHODS AND STUDY DESIGN

We conducted a prospective study of 3 months. The study involved patients with recurrent nephrolithiasis. Alongside the medical consultation, a comprehensive dietary survey was performed to assess the patients' nutritional habits. Urinary parameters, including volume, calcium, oxalate, uric acid, and power of hydrogen (pH), were evaluated both before and after the dietary intervention.

RESULTS

69 patients were involved. There were 17 patients diagnosed with cystine lithiasis, 33 with oxalocalcic lithiasis and 19 with uric lithiasis. After 3 months, only 32 patients revisited for follow-up. There were significant changes (p = 0.002 and 0.04) in urine crystalluria for cystinic and uric lithiasis. For the urinary oxalate variation, there was a significant decrease from T1 (before dietary intervention) to T2 (after dietary intervention), with levels dropping from 0.289 ± 0.10 umol/l to 0.215 ± 0.079 umol/l (p = 0.02).Regarding urinary calcium (calciuria), there was a trend toward a decrease from T1 to T2, although the change was not statistically significant, with levels decreasing from 2.42 ± 1.68 umol/l to 2.14 ± 1.62 umol/l (p = 0.1).

CONCLUSIONS

Our research underscores the favorable effects of a tailored and well-balanced diet on both the crystalluria and biological parameters of individuals with recurrent lithiasis.

Life's Essential 8 and kidney stones in US adults: mediating roles of HDL and insulin resistance

BACKGROUND

The rising incidence of kidney stones underscores the imperative to devise effective preventive measures. While a robust association between cardiovascular disease (CVD) and kidney stones exists, the current research landscape lacks investigations between cardiovascular health (CVH) and kidney stones. This study aims to explore the association between CVH, assessed by Life's Essential 8 (LE8), and kidney stones, with the role of blood lipids and insulin resistance in this relationship.

METHODS

The study included 19,942 adults aged ≥20 from the National Health and Nutrition Examination Survey of the US from 2007 to 2018. LE8, measuring CVH, includes four behavior and four factor metrics. Participants were categorized into high, moderate, and low CVH levels according to LE8 Scores: 80-100, 50-79, and 0-49, respectively. Kidney stones cases were identified through interviews and self-reported records. Weighted multivariate linear regressions, weighted logistic regressions, restricted cubic spline (RCS) analysis, mediation analyses, and sensitivity analyses were conducted.

RESULTS

In the fully adjusted logistic model, 10-point increase in LE8 Score exhibited a significant 19% reduction in kidney stones prevalence (OR=0.81, 95% CI: 0.77-0.85). The RCS confirmed the nonlinear association between LE8 Score and kidney stones (P for non-linearity: 0.004). Mediation analyses showed the mediation proportions of 19.62%, 24.26%, and 27.82% for high-density lipoprotein (HDL), insulin resistance (HOMA-IR), and serum insulin, respectively. The mediation proportions of the HOMA-IR-HDL and serum insulin-HDL pathways were 6.62% and 5.96%, respectively.

CONCLUSIONS

This study illuminates a negative association between CVH and kidney stones, providing an effective strategy for kidney stones prevention.

Lifestyle Factors and the Microbiome in Urolithiasis: A Narrative Review

Urolithiasis represents one of the most common urologic diseases, and its incidence demonstrates, globally, an increasing trend. The application of preventive measures is an established strategy to reduce urolithiasis-related morbidity, and it is based mostly on the adaptation of lifestyle factors and pharmacotherapy. Furthermore, other research areas demonstrate promising results, such as the research on the microbiome. In the current review, we searched for the latest data on lifestyle-based prevention and microbiome alterations in urolithiasis patients. The majority of the proposed lifestyle measures are already included in the urological guidelines, while additional factors, such as vitamin D supplementation, seem to have a putative positive effect. From the microbiome studies, several microbial composition patterns and metabolic pathways demonstrated an inhibiting or promoting role in lithogenesis. Up to the present, stone prevention has not shown satisfying results, which suggests that lifestyle measures are not adequate. Moreover, microbiome studies are prone to bias, since microbes are strongly affected by numerous clinical factors, while the analysis procedures are not standardized yet. Analysis standardization and data pooling from extensive registration of clinical and microbiome data are essential steps in order to improve the existing prevention strategy with targeted microbiome manipulations.

Therapeutic targets of antidiabetic drugs and kidney stones: A druggable mendelian randomization study and experimental study in rats

Diabetes is known to increase the risk of kidney stones, but the influence of antidiabetic drugs on this risk remains uncertain. Genetic instruments for antidiabetic drugs were identified as variants, which were associated with both the expression of genes encoding target proteins of drugs and glycated hemoglobin level (HbA1c). Here, we investigated the effect of antidiabetic drugs on kidney stones in a mendelian randomization (MR) framework, and further explore the potential effect on CaOx stone rat models induced by glyoxylic acid. Genetically proxied thiazolidinediones (PPARG agonists) significantly reduced the risk of kidney stones (OR = 0.42; P=0.004) per 1-SD decrement in HbA1c, while no significant association was noted in sulfonylureas, SGLT2 inhibitors, or GLP-1 analogs. Other antidiabetic drugs were not analyzed due to unclear pharmacological targets or no identified instruments. Additionally, PPARG agonists pioglitazone ameliorated CaOx nephrocalcinosis in glyoxylic acid-induced rats. The summary-data-based MR (SMR) results showed that PPARG mRNA expression in blood or kidney was not associated with kidney stone risk, and thus we performed mediation MR of PPARG agonists, circulating metabolites, and kidney stones. Among 249 circulating metabolites, we identified an indirect effect of PPARG agonists on kidney stones through increasing phospholipids to total lipids ratio in very large VLDL, with a mediated proportion of 6.87% (P = 0.018). Our study provided evidence that PPARG agonists reduced the risk of kidney stones partially via regulating lipid metabolism, and PPARG agonists may be a promising study subject in clinical studies for the prevention of kidney stones.

Intrarenal Pressure in Retrograde Intrarenal Surgery: A Narrative Review

OBJECTIVE

To review the latest evidence on the complications of elevated intrarenal pressures (IRPs) in retrograde intrarenal surgery (RIRS) and the strategies to mitigate the increase of IRP during surgery.

METHODS

A comprehensive literature search of PubMed, Web of Science and EBSCO research databases was conducted from inception to July 31, 2024. The analysis involved a narrative review.

RESULTS

Normal physiological IRP in an unobstructed kidney ranges from 0 to 15 mmHg (0-20 cmH2O). During RIRS, dangerous IRPs are often reached, resulting in complications. These include pyelorenal reflux, which predisposes the patient to fever, urosepsis and postoperative pain, and forniceal rupture, which may result in intraoperative bleeding as well as acute kidney injury, postoperative pain, and fluid overload. To maintain safe IRP, outflow should be as close as possible to inflow. Minimizing the irrigation pressure by controlling the flow rate, reducing the pressure of the irrigant fluid, using a ureteral access sheath and maintaining an empty bladder during the procedure and, more recently, using real-time IRP monitoring are appropriate techniques to mitigate unsafe IRPs.

CONCLUSION

Several complications of RIRS are related to elevated IRPs, which cause pyelorenal backflow and forniceal rupture. Irrigation flow and pressure dynamics drive IRP changes during RIRS. Awareness of these factors will allow urologists to institute strategies to mitigate IRP during RIRS, thereby reducing complications and improving patient outcomes.

Association between atherosclerosis and the development of multi-organ pathologies

Atherosclerosis is a chronic inflammatory disease affecting the vascular system, characterised by the accumulation of modified lipoproteins, immune cell aggregation and the development of fibrous tissue within blood vessel walls. As atherosclerosis impacts blood vessels, its adverse effects may manifest across various tissues and organs. In this review, we examine the association of atherosclerosis with Alzheimer's disease, stroke, pancreatic and thyroid dysfunction, kidney stones and chronic kidney diseases. In several cases, the reciprocal causative effect of these diseases on the progression of atherosclerosis is also discussed. Particular attention is given to common risk factors, biomarkers and identified molecular mechanisms linking the pathophysiology of atherosclerosis to the dysfunction of multiple tissues and organs. Understanding the role of atherosclerosis and its associated microenvironmental conditions in the pathology of multi-organ disorders may unveil novel therapeutic avenues for the prevention and treatment of cardiovascular and associated diseases.

The effect of education on pre-operative anxiety in patients undergoing extracorporeal shock wave lithotripsy

BACKGROUND

The period before diagnostic and therapeutic procedures is associated with increased anxiety levels in patients due to a lack of sufficient information. This study aimed to determine the effect of education on physiological and psychological anxiety levels in patients before extracorporeal shock wave lithotripsy (ESWL).

MATERIALS AND METHODS

This randomized clinical trial was conducted at Baharloo Hospital in Tehran on 122 patients, and the samples were selected in two stages. In the first stage, the samples were selected using convenience sampling. In the second stage, they were randomly assigned to the intervention and control groups. The data were collected using demographic information and Spielberger's State-Trait Anxiety Inventory to measure psychological anxiety. Salivary cortisol was measured to evaluate physiological anxiety by both groups before the intervention and entering the room. The intervention group received the information before ESWL via face-to-face lectures and the broadcast of pre-recorded lecture videos. The control group received only the usual care in the ward. The data analysis was performed by SPSS version 25 using descriptive statistics that included the calculation of mean, standard deviation, and frequency distribution and inferential statistics (independent t-test, paired t-test ANOVA, and Chi-square test).

RESULTS

There was no significant difference in demographic characteristics between the intervention and control groups (P > 0.05). A significant decrease in the mean salivary cortisol level was found in the intervention group compared with the control group (P < 0.001). The anxiety level was markedly decreased in the intervention group compared with the control group (P < 0.001).

CONCLUSION

Adequately informing patients before ESWL could decrease patients' physiological and psychological anxiety levels. So, people in the field of nursing education can take an important step towards using this method and reducing the anxiety of patients. The existence of such videos and holding training sessions can be a suitable solution for educating the patient.

Association between triglyceride-glucose index and risk of kidney stone: a Chinese population-based case-control study

OBJECTIVE

To investigate the association between the triglyceride-glucose (TyG) index, a surrogate marker of insulin resistance and the risk of kidney stones (KSs) in a Chinese population.

DESIGN

Case-control study.

SETTING

Three Physical Examination Centers in Shanghai, China, between January 2020 and December 2022.

PARTICIPANTS

A total of 117 757 Chinese adults underwent health check-ups during the study period.

PRIMARY AND SECONDARY OUTCOME MEASURES

The association between the TyG index and the risk of KS was assessed using multivariable logistic regression analysis. The dose-response relationship between the TyG index and KS risk was evaluated with a restricted cubic spline (RCS) analysis. Stratified analyses were conducted to explore whether factors such as age, sex, obesity, hypertension and diabetes modify the association between the TyG index and KS risk.

RESULTS

Out Of the 117 757 participants, 11 645 (9.9%) were diagnosed with KS using ultrasound. Individuals with KS had significantly higher TyG values than controls (p<0.001). The multivariable-adjusted ORs for KS increased across TyG quartiles, with the highest quartile showing an OR of 1.28 (95% CI 1.20 to 1.36) compared with the lowest quartile. Each SD increase in the TyG index was associated with a 10% higher risk of KS (OR: 1.10, 95% CI 1.08 to 1.13). RCS analysis revealed a significant positive and linear association between TyG index and KS (p overall<0.001, p non-linear=0.136). The positive association persisted across the subgroup and sensitivity analyses.

CONCLUSIONS

The TyG index was positively associated with the risk of prevalent KS, suggesting that insulin resistance may be a risk factor for KS in the Chinese population.

The association of glyphosate exposure with kidney stones in American adults: A nationally representative cross-sectional study

OBJECTIVE

Glyphosate has been ubiquitously present in our living environment due to its efficient herbicidal ability, but its association with the prevalence of kidney stones remains uncertain. This study aims to explore the impact of glyphosate exposure on kidney stones and to investigate the mediating effects of some serologic indicators. Furthermore, we attempt to identify the specific populations at greater risk of exposure.

METHODS

This is a cross-sectional study of the U.S. adult population examining the association between glyphosate exposure and kidney stones based on data from the 2013-2018 National Health and Nutrition Examination Survey (NHANES). We implemented multi-model-adjusted logistic regression and smoothed curve fitting to explore the connection between them. Further subgroup analyses were conducted to confirm the magnitude of exposure risk in specific populations. Mediation effects analysis served to provide insight into the underlying mechanisms of the link.

RESULTS

A total of 4302 participants' health data were ultimately analyzed, and the prevalence of kidney stones was 10.85 %. Participants with the highest urinary glyphosate(uGLY) content(Q3) had a higher prevalence of kidney stones compared with participants with the lowest uGLY content(Q1) (OR=1.70, 95 %CI: 1.10-2.63). Smoothed curve fitting revealed a linear positive association between ln-transformed uGLY and kidney stones (OR=1.21,95 %CI:1.08-1.37, LLR=0.291), and this exposure-outcome effect was at greater risk in men (OR=1.24,95 %CI: 1.05-1.46), non-Hispanic whites (OR=1.29, 95 %CI: 1.09-1.53), and hypertensive groups (OR=1.23,95 %CI: 1.05-1.44). Serum biochemical markers HDL, ALP, and serum glucose partially mediated the correlation between glyphosate and kidney stones (2.44-4.20 %).

CONCLUSION

Glyphosate exposure is significantly associated with the prevalence of kidney stones. In men, non-Hispanic whites, and hypertensive populations, the management of glyphosate exposure should be emphasized, and appropriate protective strategies may be beneficial in reducing the burden of kidney stones. More high-quality clinical inquiries and animal toxicology experiments are still required to verify the reliability of our findings and their underlying mechanisms.

Evaluating the lipid accumulation product index as a predictor for kidney stone prevalence: insights from NHANES 2007-2018

PURPOSE

This study aimed to explore the relationship between the lipid accumulation product (LAP) index and kidney stone prevalence, utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2018.

METHODS

An observational study was executed employing the NHANES dataset from 2007 to 2018. Analytical methods encompassed multivariate logistic regression, restricted cubic splines (RCS), subgroup analysis, and interaction tests. Predictions were made using the receiver operating characteristic (ROC) curve and the area under the curve (AUC) values.

RESULTS

The analysis included 9744 adults aged 20 years and older. Multivariate logistic regression identified a significant positive association between log2-transformed LAP (treated as a continuous variable) and kidney stone risk across all models, with odds ratios (ORs) exceeding 1 and p values less than 0.001. Categorically, ORs escalated with increasing LAP levels, indicating a dose-response relationship. The RCS analysis confirmed a linear positive correlation between log2-transformed LAP and kidney stone risk. Subgroup analyses revealed that the log2-transformed LAP-kidney stones relationship was consistent, unaffected by stratification across the examined variables. In addition, LAP index (AUC = 0.600) proved to be a more effective predictor of kidney stones compared to body mass index (AUC = 0.584).

CONCLUSION

Elevated LAP levels are positively correlated with a higher incidence of kidney stones, signifying its potential as a risk marker for this condition. Future research should investigate the mechanisms underlying this relationship. LAP can be used as a new anthropometric index to predict kidney stones, and its predictive ability is stronger than body mass index.

RIRS with FV-UAS vs. ESWL for the management of 1-2 cm lower pole renal calculi in obese patients: a prospective study

Objective

To evaluate the efficacy and safety of retrograde intrarenal surgery (RIRS) combined with flexible vacuum-assisted ureteral access sheath (FV-UAS) versus extracorporeal shock wave lithotripsy (ESWL) for the management of 1-2 cm lower pole renal calculi (LPC) in obese patients.

Patients and methods

This prospective, randomized study included 149 obese patients with 1-2 cm LPC. Patients were allocated into two groups: 76 patients underwent RIRS with FV-UAS, and 73 patients received ESWL. The parameters assessed included stone-free rate (SFR), retreatment rate, complications, operative time, and pain intensity measured by the visual analog scale (VAS). Stone-free status was defined as the absence of stones on computed tomography or residual fragments smaller than 4 mm at 4 weeks post-procedure.

Results

The baseline characteristics of the two groups were comparable. The SFR was significantly higher in the RIRS group, reaching 86.8%, compared to 63.0% in the ESWL group (p = 0.034). Furthermore, the retreatment rate was significantly lower in the RIRS group, at 5.2%, versus 24.7% in the ESWL group (p < 0.001). The average operative time for RIRS was notably longer, at 65.3 ± 6.4 min, compared to 25.3 ± 7.8 min for ESWL (p < 0.001). The complication rates were 9.2% for the RIRS group and 6.8% for the ESWL group, with no statistically significant difference (p = 0.326). All complications were classified as Grade I or II according to the modified Clavien classification system. No significant differences were observed between the two groups regarding pain VAS scores and the composition of the stones.

Conclusion

RIRS with FV-UAS demonstrated superior efficacy, evidenced by a higher SFR and reduced retreatment rates compared to ESWL, despite a longer operative duration. Both treatment modalities showed comparable safety profiles. RIRS with FV-UAS emerges as a viable, effective, and reproducible intervention for managing 1-2 cm LPC in obese patients, providing significant clinical advantages.

Trajectories of body mass index and incident kidney stone disease: a prospective cohort study in Chinese young adults

The present study aims to explore the potential changing trajectory patterns of body mass index (BMI) for Chinese young adults and identify the relationship of BMI trajectory patterns with kidney stone disease (KSD) incidence. Latent class growth analysis was used to identify distinct trajectories of BMI during young adulthood. Cox proportion hazard models were conducted to explore the association between the BMI trajectory group memberships and incident KSD. Subgroup and sensitivity analyses were undertaken to test the robustness of the findings. In total, 2,966 young adults who attended at least three annual check-ups from 2014 to 2021 without KSD at baseline were enrolled in the cohort analysis. Three district BMI trajectories were identified for young adults, labeled as low-stable in normal BMI (28.5%), medium-rising to high BMI (67.4%), and rapid-rising to high BMI (4.1%). Compared with the low-stable in normal BMI group, Hazard ratios (HRs) of the rapid-rising and medium-rising to high BMI groups were 3.19 (95% CI: 1.54-6.63) and 1.78 (95% CI: 1.08-2.92) after adjusting the covariates. The cumulative incidence curves likewise illustrated that young adults in the rapid-rising to high BMI group had the highest risk of developing KSD compared to the other two groups. The rapid BMI growth trajectories during young adulthood were identified to be independently associated with a higher risk of KSD. The findings supplied novel insights that monitoring the BMI changing pattern may be favorable to early intervention of KSD during young adulthood.

Association between daily sitting time and kidney stones based on the National Health and Nutrition Examination Survey (NHANES) 2007-2016: a cross-sectional study

BACKGROUND

Kidney stones are among the most common urological conditions affecting ~9% of the world population. Although some unhealthy diets and unhealthy lifestyles are reportedly risk factors for kidney stone, the association between daily sitting time and kidney stone has not been explored.

MATERIALS AND METHODS

This large-scale, cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) database 2007-2016. Kidney stone history and daily sitting time were retrieved from the questionnaire and 24 hour (h) recall interviews. Logistic regression and subgroup analysis were conducted to investigate the association. The analysis was further stratified by vigorous recreational activity.

RESULTS

A total of 19 188 participants aged ≥20 years with complete information were included in this study. The overall prevalence of kidney stone was 9.6%. Among participants without vigorous recreational activity, a trend towards an increasing prevalence of kidney stone was observed with increased daily sitting time. However, the trend was not observed in individuals who participated in vigorous recreational activity, as they experienced a decreased risk of kidney stone despite having a daily sitting time of 6-8 h (crude model OR=0.659, 95% CI: 0.457-0.950, P =0.028), indicating that vigorous recreational activity may partially attenuate the detrimental effect of prolonged sitting time.

CONCLUSION

Our study revealed an increasing trend of prevalence of kidney stone with increased daily sitting time among the population not performing vigorous recreational activity despite the difference was nonsignificant. Vigorous recreational activity may modify the association between daily sitting time and kidney stone. More prospective cohort studies are warranted to further examine this association.

Changes in metabolic overweight phenotypes over time and risk of nephrolithiasis: a cohort study

BACKGROUND

Overweight/obesity is considered an independent risk factor for nephrolithiasis, but little is known about its effect on nephrolithiasis according to metabolic health status.

OBJECTIVES

We aimed to investigate the association between various metabolic overweight phenotypes and the occurrence of nephrolithiasis. It also explores whether changes in these phenotypes over time influence the risk of nephrolithiasis.

MATERIALS AND METHODS

A total of 10,315 participants free of nephrolithiasis who underwent an annual health checkup from 2017 to 2022 were included in our prospective cohort study. They were categorized into four groups according to the presence of overweight and metabolic abnormalities (MA). The primary endpoint was the occurrence of renal stones. Multivariable Cox analysis was conducted to elucidate the relationship between metabolic overweight phenotypes and incident nephrolithiasis.

RESULTS

During a median follow-up duration of 4.02 years, nephrolithiasis occurred in 1,468 (14.23%) participants. In the full cohort, we observed that the 5-year cumulative incidences of nephrolithiasis were highest in the metabolically healthy overweight (MHO) and metabolically abnormal overweight (MAO) groups. The hazard ratios (HRs) for nephrolithiasis, relative to metabolically healthy normal weight (MHNW), ranged from 1.19 (95% CI:1.03-1.37; MHO) to 1.32 (95% CI:1.15-1.51; MAO). Furthermore, individuals with persistent MHO throughout follow-up were at a 1.42-fold increased risk of nephrolithiasis (P < 0.001), and 32.17% of individuals experienced changes in phenotype during follow-up. Among MAO subjects, those who transitioned to MHO and MHNW had a 26% and 45% lower risk of incident nephrolithiasis, respectively, compared to those who persisted in the MAO phenotype.

CONCLUSION

Individuals in the MHO and MAO groups exhibit an elevated risk of incident nephrolithiasis in this prospective cohort study. A significant proportion of nephrolithiasis cases may be potentially preventable through the appropriate management of metabolic risk factors for MAO subjects.

Visceral Adiposity and Its Impact on Nephrolithiasis: A Narrative Review

Kidney stones represent a serious medical problem, resulting from several factors such as diet, genetics, and certain medical conditions. Visceral adipose tissue has been shown in recent research to play a significant role in kidney stone formation, making it a more precise indicator than traditional obesity indicators such as body mass index. The main aim of this review is to summarize studies on visceral obesity as a predictive marker for nephrolithiasis and to highlight new mechanistic pathways such as adipokine-mediated inflammation and its impact on kidney stone formation. This review emphasizes the importance of considering visceral fat in the prevention and management of kidney stones, suggesting that targeted strategies to reduce visceral fat could decrease the incidence of kidney stones and their management costs. Further prospective studies are needed to validate these findings and propose preventive strategies based on visceral adiposity assessments.

The Multidisciplinary Approach in the Management of Patients with Kidney Stone Disease-A State-of-the-Art Review

Kidney stone disease has a multifactorial etiology, and evolving dietary habits necessitate continuous updates on the impact of dietary components on lithogenesis. The relationship between diseases influenced by lifestyle, such as obesity and diabetes, and kidney stone risk underscores the need for comprehensive lifestyle analysis. Effective management of kidney stones requires a multidisciplinary approach, involving collaboration among nutritionists, urologists, nephrologists, and other healthcare professionals to address the complex interactions between diet, lifestyle, and individual susceptibility. Personalized dietary therapy, based on each patient's unique biochemical and dietary profile, is essential and necessitates comprehensive nutritional assessments. Accurate dietary intake evaluation is best achieved through seven-day, real-time dietary records. Key factors influencing urinary risk include fluid intake, dietary protein, carbohydrates, oxalate, calcium, and sodium chloride. Personalized interventions, such as customized dietary changes based on gut microbiota, may improve stone prevention and recurrence. Current research suggests individualized guidance on alcohol intake and indicates that tea and coffee consumption might protect against urolithiasis. There is potential evidence linking tobacco use and secondhand smoke to increased kidney stone risk. The effects of vitamins and physical activity on kidney stone risk remain unresolved due to mixed evidence. For diseases influenced by lifestyle, conclusive evidence on targeted interventions for nephrolithiasis prevention is lacking, though preliminary research suggests potential benefits. Management strategies emphasize lifestyle modifications to reduce recurrence risks, support rapid recovery, and identify predisposing conditions, highlighting the importance of these changes despite inconclusive data.

The awareness of renal stones amongst Syrian refugees in northern Jordan

Kidney Stone Disease (KSD) is a globally prevalent condition that can be effectively addressed through proper education. This study investigated the awareness of kidney stones among refugees residing in northern Jordan. A questionnaire was administered to 487 refugees of diverse ages and socioeconomic backgrounds. Notably, 97.3% of the respondents had not attended university, and 30.8% held unskilled jobs. Upon familiarizing themselves with the signs and symptoms of kidney stones, 16.22% of men and 12.32% of women reported experiencing such symptoms. This revealed a significant association, suggesting that men might be more susceptible to developing kidney stones than women due to a lack of medical follow-up and examination for men in the camp. However, 38.77% of individuals were uncertain whether they had kidney stones. Furthermore, 38.96% of refugees were unsure about which healthcare professional to consult when experiencing kidney stone symptoms. This report highlights a serious issue with refugees' knowledge of the symptoms, causes, and treatments for kidney stones. The results indicate that Syrian refugees face challenges in acquiring adequate disease awareness, potentially related to issues of migration and war, including low levels of education, limited income, living in camps, and difficulties accessing treatments when needed. Implementing additional policies is necessary to address these challenges among Syrian refugees; however, further studies are needed to validate these findings.

Introducing an lsoprenaline Eluting Guidewire: Report on its Design and the Results of the Dose-Determining Pilot Study

Introduction: Retrograde intrarenal surgery (RIRS) is associated with complications, many of which are related to the intrarenal pressure (IRP). We aim to describe the design of a novel isoprenaline-eluting guidewire ("IsoWire") and present the results from the first in vitro release studies and the first animal studies showing its effect on IRP. Materials and Methods: The IsoWire comprises a Nitinol core surrounded by a stainless-steel wire wound into a tight coil. The grooves created by this coil provided a reservoir for adding a hydrogel coating into which isoprenaline, a beta-agonist, was loaded. Animal studies were performed using a porcine model. For the control, IRP, heart rate (HR), and mean arterial pressure (MAP) were measured continuously for 6 minutes with a standard guidewire in place. For the experiment, the standard hydrophilic guidewire was removed, the IsoWire was inserted into the renal pelvis, and the same parameters were measured. Results: In vitro analysis of the isoprenaline release profile showed that most (63.9 ± 5.9%) of the loaded drug mass was released in the 1st minute, and almost all of the drug was released in the first 4 minutes exponentially. Porcine studies showed a 25.1% reduction in IRP in the IsoWire that released 10 μg in the 1st minute; however, there was a marked increase in HR. The average percentage reduction in IRP was 8.95% and 21.3% in the IsoWire that released 5 and 7.5 μg of isoprenaline, respectively, with no changes in HR or MAP. Conclusions: The IsoWire, which releases 5 and 7.5 μg of isoprenaline in the 1st minute, appears to be safe and effective in reducing the IRP. Further studies are needed to establish whether the isoprenaline-induced ureteral relaxation will render easier insertion of a ureteral access sheath, reduce IRP during sheathless RIRS, or even promote the practice of sheathless RIRS.

Analyzing global research trends and focal points in the utilization of laser techniques for the treatment of urolithiasis from 1978 to 2022: visualization and bibliometric analysis

Laser lithotripsy is gaining global prominence and is a dynamically progressing field marked by a continual influx of new and comprehensive research each year. Recently, there has been a noticeable shift toward the adoption of various kinds of lasers, such as holmium: yttrium-aluminum-garnet (Ho:YAG) and thulium fiber (TFL) lasers. Consequently, we aim to conduct a bibliometric analysis to analyze key areas of research activity within scientific publications that center on the utilization of laser techniques in urolithiasis. A search of the literature spanning from 1978 to 2022 was carried out on 25 December 2023 using the Scopus database to explore research related to the application of laser techniques for urolithiasis treatment. Visualization analysis was performed using VOSviewer software (version 1.6.20). We examined 962 publications that met the specified criteria, 791 (82.22%) of which were original articles. The analysis of the retrieved publications indicated a consistent increase in research output from 1978 to 2022; a particularly noteworthy surge occurred after 2003. In particular, the U.S. claimed the leading position as the most productive country, contributing 211 articles (21.93%). However, India had the highest research productivity according to the adjustment index of 19.08. In the European region, 324 publications (33.68% of the total) originated from 25 countries. The Journal of Endourology contributed the most between 1978 and 2022 (n = 96, 9.98%). The most cited paper examined the effectiveness of holmium: yttrium-aluminum-garnet (Ho:YAG) lasers, while a subsequent study focused on the use of a thulium fiber laser (TFL), an emerging laser technology that has gained increased recognition. Co-occurrence analysis revealed three distinct clusters focusing on the types of laser technology, minimally invasive approaches, and success rate/postoperative complications. This comprehensive investigation delves into the global landscape of laser use for the treatment of urolithiasis. This review supports the emerging clinical concept of using various types of laser technology for urolithiasis treatment. Moreover, the hot issues that researchers should focus on based on the findings of this study are the use of different types of laser lithotripsy in view of the surgical approach, success rate and complications.

Basal metabolic rate and the risk of urolithiasis: a two-sample Mendelian randomization study

OBJECTIVE

Few studies have investigated the impact of basal metabolic rate (BMR) on the development of urolithiasis, and the causal relationship is yet to be established. In this study, a two-sample Mendelian randomization (MR) analysis was utilized to identify the causal relationship between BMR and risk of urolithiasis.

METHOD

Genetic instruments for BMR were drawn from a public genome-wide association study (GWAS). Summary dates on BMR and urolithiasis were obtained from a GWAS meta-analysis with sample sizes of 454,874 and 212,453, respectively. The inverse-variance weighted (IVW) method was provided as the main approach to estimate the causal relationship. The weighted-median method and the MR-Egger method were used as supplements to the IVW method. In addition, we conducted sensitivity analyses, including heterogeneity tests, pleiotropy tests and leave-one-out analysis, to assess the robustness of the outcomes. Furthermore, the funnel plot asymmetry was visually inspected to evaluate possible bias.

RESULTS

The inverse-variance weighted data revealed that genetically predicted BMR significantly decreased the risk of urolithiasis [beta coefficient (beta): - 0.2366, odds ratio (OR): 0.7893, 95% confidence interval (CI) 0.6504-0.9579, p = 0.0166].

CONCLUSIONS

BMR has causal effects on urolithiasis in an MR study, and the risk of urolithiasis in patients with lower levels of BMR is higher.

Deciding on a novel predictive value to gauge how well patients with lower ureteric stones respond to medical expulsive therapy

This study, conducted over 4 years in Baghdad, Iraq, aimed to determine the importance of ureteric jet assessment in medical expulsive therapy (MET) for distal ureteral stones. A total of 156 patients with distal ureteral stones (≤ 10 mm) participated, and their ureteric jets were observed using a color Doppler scanner before and after 2 weeks of MET. The main focus was the success rate of stone expulsion. Our results showed that 50% of patients had detectable ureteric jets after 2 weeks of MET, and 21.8% experienced successful stone expulsion. After 4 weeks, 23.7% achieved stone expulsion, while 54.5% still had remaining stones. Patients who had a positive baseline ureteric jet were significantly more likely to successfully expel their stones. This study highlights the importance of monitoring ureteric jet movement in MET for distal ureteral stones.

Epidemiological and biological associations between cardiovascular disease and kidney stone formation: A systematic review and meta-analysis

AIMS

Previous studies find kidney stone formers (KSF) are at greater risk of developing cardiovascular disease (CVD). The underlying mechanisms are poorly understood, and many clinicians are unaware of this connection. We will: DATA SYNTHESIS: Our systematic review is registered with PROSPERO (ID CRD42021251477). We searched epidemiological and biological data. The epidemiological search generated 669 papers, narrowed down to 15. There were 4,259,869 participants (230,720 KSFs). KSF was associated with 25% higher risk of coronary artery disease (CAD) (95% confidence interval (CI): 15, 35%), 17% higher risk of stroke/transient ischemic attacks (TIA) (CI:10, 25%) and 39% higher risk of arterial disease (AD) (CI: 17 65%). Significant heterogeneity was found. Female-identifying KSFs had a higher risk of stroke (ratio = 1.10) and CAD (1.20). The biological search generated 125 papers, narrowed down to 14. Potential underlying mechanisms were extracted and discussed, including intimal/medial vascular calcification, oxidative stress via osteopontin (OPN), cholesterol-induced pathology, and endothelial dysfunction.

CONCLUSIONS

There is a significant association between KSF and CVD, supporting the consideration of KSF as a systemic, calcium-mediated disease. Clinicians will benefit from being aware of this connection.

Prospective Comparative Analysis of Supine Versus Prone Percutaneous Nephrolithotomy in Patients with Complex Renal Stone Disease and Difficult Anatomy

OBJECTIVE

 In complex renal stone disease, few studies have shown that supine percutaneous nephrolithotomy (PCNL) is not inferior to prone PCNL. In our study, we evaluated the safety and efficacy of supine versus prone PCNL in patients with complex renal stone disease and patients with difficult anatomy.

METHODS

 We prospectively analyzed 106 patients over 15 months from October 2022 to December 2023 and divided them as group S (Calcutta position supine arm) and group P (classical prone arm) by simple randomization. The measured data included body mass index (BMI), stone size, location of stone, number of punctures/ access, tract length, bleeding, operative time, stone-free rate (SFR), length of hospital stay, and postoperative complications.

RESULTS

 The operative time was 104.722 ± (34.48) versus 124.30 ± (22.67) minutes (group S vs. group P), which was significant (P=.01). The nephroscopy time was 89.722 ± 34.55 in group S vs. 92.212 ± 20.18 minutes, which was also significant (P = .01). The mean postoperative hospital stay was 3.889 ± 1.09 and 4.558 ± 1.33 days in supine and prone group (P = .021), respectively. Four patients in group S required re-look PCNL in comparison to 8 in group P. Overall SFR at 1 month was 76.92% and 68.51% (P .331), respectively in case of group S and P.

CONCLUSION

 The study revealed that supine position in Calcutta position is a viable alternative to classical prone position even in patients with complex renal stone and patients with difficult anatomy as major complications are less, SFR is higher, and need of auxiliary procedures are rare.

Sodium-Glucose Cotransporter 2 Inhibitors and Nephrolithiasis Risk in Patients With Type 2 Diabetes

Importance

Type 2 diabetes (T2D) is associated with an increased risk of kidney stones. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) might lower the risk of nephrolithiasis by altering urine composition. However, no studies have investigated the association between SGLT2i use and nephrolithiasis risk in patients receiving routine care in the US.

Objective

To investigate the association between SGLT2i use and nephrolithiasis risk in clinical practice.

Design, Setting, and Participants

This new-user, active comparator cohort study used data from commercially insured adults (aged ≥18 years) with T2D who initiated treatment with SGLT2is, glucagon-like peptide 1 receptor agonists (GLP-1RAs), or dipeptidyl peptidase 4 inhibitors (DPP4is) between April 1, 2013, and December 31, 2020. The data were analyzed from July 2021 through June 2023.

Exposure

New initiation of an SGLT2i, GLP-1RA, or DPP4i.

Main Outcomes and Measures

The primary outcome was nephrolithiasis diagnosed by International Classification of Diseases codes in the inpatient or outpatient setting. New SGLT2i users were 1:1 propensity score matched to new users of a GLP-1RA or DPP4i in pairwise comparisons. Incidence rates, rate differences (RDs), and estimated hazard ratios (HRs) with 95% CIs were calculated.

Results

After 1:1 propensity score matching, a total of 716 406 adults with T2D (358 203 pairs) initiating an SGLT2i or a GLP-1RA (mean [SD] age, 61.4 [9.7] years for both groups; 51.4% vs 51.2% female; 48.6% vs 48.5% male) and 662 056 adults (331 028 pairs) initiating an SGLT2i or a DPP4i (mean [SD] age, 61.8 [9.3] vs 61.7 [10.1] years; 47.4% vs 47.3% female; 52.6% vs 52.7% male) were included. Over a median follow-up of 192 (IQR, 88-409) days, the risk of nephrolithiasis was lower in patients initiating an SGLT2i than among those initiating a GLP-1RA (14.9 vs 21.3 events per 1000 person-years; HR, 0.69 [95% CI, 0.67-0.72]; RD, -6.4 [95% CI, -7.1 to -5.7]) or a DPP4i (14.6 vs 19.9 events per 1000 person-years; HR, 0.74 [95% CI, 0.71-0.77]; RD, -5.3 [95% CI, -6.0 to -4.6]). The association between SGLT2i use and nephrolithiasis risk was similar by sex, race and ethnicity, history of chronic kidney disease, and obesity. The magnitude of the risk reduction with SGLT2i use was larger among adults aged younger than 70 years vs aged 70 years or older (HR, 0.85 [95% CI, 0.79-0.91]; RD, -3.46 [95% CI, -4.87 to -2.05] per 1000 person-years; P for interaction <.001).

Conclusions and Relevance

These findings suggest that in adults with T2D, SGLT2i use may lower the risk of nephrolithiasis compared with GLP-1RAs or DPP4is and could help to inform decision-making when prescribing glucose-lowering agents for patients who may be at risk for developing nephrolithiasis.

Prognostic Factors for Residual Lithiasis in Patients With Staghorn Calculi Undergoing Percutaneous Nephrolithotomy in the Maya Region of Yucatan, Mexico: A Case-Control Study

BACKGROUND

Yucatan stands out as the state with the highest prevalence of urolithiasis in Mexico, placing significant demands on healthcare services, such as consultation and surgical intervention. Staghorn calculi are related to recurrent urinary tract infections, and their management is always surgical. The stone-free rate is a parameter used to measure the success of surgery, with residual stones considered those persisting four weeks after surgical management. There are understudied prognostic factors that can predict the success of achieving stone-free status, taking into account the number of stones, their location, and the anatomical variations of the patient's collecting system. The study aims to determine the prognostic factors for residual lithiasis in patients with staghorn calculi treated with percutaneous nephrolithotomy at the High Specialty Regional Hospital of the Yucatan Peninsula.

METHODS

A case-control study was performed including 188 patients, aged 18 years or older, and diagnosed with staghorn calculus from January 2022 to June 2023, grouping the patients according to their stone-free rate evidence on postoperative computed tomography. Data were collected from the records of the Urology Department at a high-specialty hospital in Yucatan. The groups were analyzed, aiming to establish an association between preoperative factors and postoperative outcomes measured in terms of stone-free rate.

RESULTS

A total of 188 patients with staghorn calculi were included, with a predominance in females (58.5%) and a mean age of 45.4 ± 11.9 years. The most common comorbidity was hypertension (29.8%), and 27.7% had a history of recurrent urinary tract infections. Regarding the Sampaio classification, B1 was the most prevalent in our population with 66 cases (35.1%), while Type A2 was the least common (13.8%). According to what was obtained through the multivariate logistic regression model, the calyceal anatomy Type A1 and A2 were associated with residual lithiasis (p= 0.016 OR: 2.994 CI: 1.223-7.331), and Grade IV was associated with a higher rate of residual lithiasis (p=0.005 CI: 1.586-13.100). A statistically significant association was found between stone burden and the presence of residual lithiasis (p=< 0.001).

CONCLUSION

Guy's Score Grade IV showed a higher incidence of residual lithiasis, seemingly associated with stone burden, leading to the conclusion that both factors were categorized as predictors for the development of post-surgical residual lithiasis. Regarding anatomical variations according to Sampaio, it was observed that types A1 and A2 showed a lower rate of stone-free status. Therefore, we also consider them as variables that may influence the achievement of success in endourological management. Personalized patient assessment allows for more accurate prognostic factors, enabling a more comprehensive surgical planning in the presence of staghorn calculi.

Effects of body mass index on urinary lithogenic factors in urinary system stone patients

AIM

Obesity and metabolic syndrome are becoming more prevalent these days. In addition, we know that urinary stone disease is also on the rise. In this study, we wanted to examine if body mass index (BMI) had a negative effect on the stone disease by evaluating 24-hour urinalysis in stone patients and recurrence rates in our region.

Management of nephrolithiasis in the Middle East over a recent decade: A systematic review

Nephrolithiasis is a prevalent issue around the globe, particularly in hot climates such as Saudi Arabia. This analysis's objectives were to investigate the characteristics of kidney stones in Eastern Saudi Arabia and to provide the following findings: urinary stone composition, gender and age distribution, seasonal variations in stone formation, coexisting diseases linked to stone development, and urinary stone incidence. With comparisons to European and American populations, the primary risk factors for nephrolithiasis in Asian populations are to be determined through this systematic review and meta-analysis. We synthesized data from 13 geographically different studies using a thorough literature search through PubMed, ScienceDirect, and ResearchGate following the Preferred Reporting Items of Systematic Reviews and Meta-Analyses criteria. Potential targets for specialized public health programs were highlighted by the elucidation of differences in health-care-seeking behavior and disparities in health-care access. The results of this systematic analysis give doctors, researchers, and policymakers a thorough understanding of the condition of nephrolithiasis care in Saudi Arabia today. In addition, to maximize the care of nephrolithiasis in this particular group, this review identifies information gaps and highlights the necessity of context-specific guidelines and future research initiatives. All things considered, this systematic review addresses the unique possibilities and problems that exist within the Saudi Arabian health-care sector while also adding to the worldwide conversation on nephrolithiasis.

The association of dyslipidemia with kidney stone: result from the NHANES 2007-2020

OBJECTIVE

To examine the association between dyslipidemia and kidney stone disease (KSD).

METHODS

A cross-sectional study data from 2007 to 2020 National Health and Nutrition Examination Survey (NHANES) were analyzed. Multivariate logistic regression was conducted with serum lipid levels as the exposure and presence of KSD as the outcome, and included adjustment for confounders and subgroup analysis.

RESULTS

A total of 38,617 participants were enrolled and classified into two groups according to whether they ever had (n = 3689) or did not have (n = 34,928) KSD. After multivariate logistic regression models, compared to quartile 1 (Q1) of lipid profile, the participants in Q3 (OR 0.8380; 95 CI 0.7380, 0.9515, P < 0.01) and Q4 (OR 0.7373; 95 CI 0.6377, 0.8525, P < 0.01) of high-density lipoprotein cholesterol (HDL) had a significantly lower risk of KSD in adjusted model 3. Results remained stable after stratified by age, gender, and body mass index (BMI) in subgroup analysis. No association was observed between low-density lipoprotein cholesterol (LDL), total cholesterol (TC) and triglycerides (TG) levels, and KSD.

CONCLUSIONS

Low HDL was associated with a higher risk of kidney stones in the USA adult population.

The impact of early sports participation on body fatness in adulthood is not mediated by current physical activity

OBJECTIVE

The aim was to analyze the relationship between early sports participation (ESP) and body fatness (BF) in adults, as well as to identify whether this possible relationship is directly influenced by the current physical activity (PA) level.

METHODS

This cross-sectional study combined baseline data of two cohort. The BF estimated by DXA. The ESP, the subjects reported the engagement in sports during childhood (7-10 years) and adolescence (11-17 years) through two yes/no questions and current PA (described as steps) was device-measured using pedometers. Were identified as potential covariates and therefore adjusted the multivariate models: age, ethnicity, alcohol consumption, smoking, and sleep quality. Statistical analysis consisted of the chi-square test, analysis of variance/covariance, and structural equation modeling (software BioEstat version 5.0; p-value < .05).

RESULTS

Adults engaged in ESP had lower BF; among women, the variance in BF explained by ESP was 25.5%; among men, it was 9.2%. Sports participation in early life (r = -.436 [95% CI: -0.527 to -0.346]) and current PA (r = -.431 [95% CI: -0.522 to -0.340]) were inversely related to BF, as well as positively related to each other (r = .328 [95% CI: 0.226 to 0.430]). In the mediation model, current PA partially mediated (18.5%) the impact of ESP on BF, while current PA and ESP remained relevant determinants of BF.

CONCLUSION

Early sports participation and current PA have a significant impact on BF in adulthood, which is of similar magnitude and independent of each other.

Association between body mass index, metabolic syndrome and common urologic conditions: a cross-sectional study using a large multi-institutional database from the United States

INTRODUCTION

The study aims to determine whether body mass index (BMI), metabolic syndrome (MS) or its individual components (primary hypertension, type 2 diabetes mellitus and dyslipidemias) are risk factors for common urological diseases.

MATERIALS AND METHODS

Cross-sectional study with data collected on February 28, 2022 from the TriNetX Research Network. Patients were divided in cohorts according to their BMI, presence of MS (BMI > 30 kg/m2, type 2 diabetes mellitus, primary hypertension and disorders of lipoprotein metabolism) and its individual components and its association with common urological conditions was determined. For each analysis, odds ratio (OR) with 95% confidence intervals were calculated. Statistical significance was assessed at p < .05.

RESULTS

BMI > 30 kg/m2 was associated with increased risk of lithiasis, kidney cancer, overactive bladder, male hypogonadism, benign prostatic hyperplasia, and erectile dysfunction (p < .05). On the contrary, BMI was inversely associated with ureteral, bladder and prostate cancer (p < .05). In all urological diseases, MS was the strongest risk factor, with prostate cancer (OR = 2.53) showing the weakest and male hypogonadism the strongest (OR = 13.00) associations.

CONCLUSIONS

MS and its individual components were significant risk factors for common urological conditions. Hence holistic approaches with lifestyle modification might prevent common urological disease.Key messagesOverall, metabolic syndrome is the strongest risk factor for all the analysed urological diseases.Abnormally high body mass index can be a risk or protective factor depending on the threshold and urological disease that are being evaluated.Metabolic syndrome and increased BMI should be considered important factors associated to the prevalence of common urological diseases.

Inverse association of glucosamine use and risk of new-onset kidney stones in UK adults with less sedentary time

OBJECTIVE

To assess the association of different sedentary behaviors and glucosamine use with the risk of kidney stones and examine the modification of genetic risk of kidney stones on this association.

METHODS

473,225 participants free of kidney stones at baseline from the UK Biobank were included. Total sedentary time was calculated as the sum of the duration of TV-watching, driving, and non-occupational computer using. The primary outcome was new-onset kidney stones.

RESULTS

During a median follow-up of 12.0 years, 5528 cases of kidney stones were documented. All major sedentary behaviors and total sedentary time were significantly positively related to the risk of kidney stones (All P for trend<0.05). Participants with total sedentary time ≥ 3.5 h/day had a significantly higher risk of new-onset kidney stones (vs. <3.5 h/day [tertile 1]; HR, 1.18; 95%CI,1.10-1.27). Compared with non-users, participants who regularly used glucosamine had a significantly lower risk of new-onset kidney stones in those with total sedentary time < 3.5 h/day (HR, 0.72; 95%CI,0.59-0.86), but not in those with total sedentary time ≥ 3.5 h/day (HR, 0.99; 95%CI,0.91-1.08; P-interaction = 0.001). Among participants with total sedentary time < 3.5 h/day, there was a dose-response relationship of glucosamine use with new-onset kidney stones (P for trend<0.001). Genetic risks of kidney stones did not significantly modify the association.

CONCLUSIONS

TV-watching, driving and non-occupational computer using were all positively associated with the risk of new-onset kidney stones. Glucosamine use was associated with a lower risk of new-onset kidney stones in participants with total sedentary time < 3.5 h/day, following a dose-response relationship.

Association between oxidative balance score and kidney stone in United States adults: analysis from NHANES 2007-2018

Purpose: To investigate the relationship between the Oxidative Balance Score (OBS) and kidney stone risk using NHANES 2007-2018 data, and to explore potential mechanisms and population-specific effects. Materials and methods: Data from the NHANES 2007-2018 were analyzed. OBS was calculated based on 16 dietary components and 4 lifestyle components. Multivariate logistic regression was employed to investigate the relationship between OBS and kidney stone. Further stratified analyses were conducted to examine the associations across different subgroups. Results: A total of 19,799 participants were included in the study. There was a consistent inverse association between OBS and the risk of kidney stones (OR = 0.97; 95% CI: 0.96-0.99). After dividing the participants into quartiles based on OBS, compared to the lowest quartile of OBS, the risk of kidney stones in the highest quartile of OBS was reduced by 33% (95% CI 0.50-0.89; p = 0.002). This association was consistent across both dietary and lifestyle OBS scores. The protective effect of OBS was notably pronounced among Non-Hispanic white and Other race groups, and among individuals with a higher level of education. However, the association was not significant among individuals with diabetes. Conclusion: A higher OBS, indicating a balance skewed towards antioxidants, is associated with a reduced risk of kidney stones, especially among specific population subgroups. These findings underscore the potential role of oxidative balance in kidney stone pathogenesis and highlight the importance of considering individual and population-specific factors in future research and preventive strategies.

Lifestyle and Diet as Risk Factors for Urinary Stone Formation: A Study in a Taiwanese Population

Background and Objectives: Urinary tract stones have long been a common ailment afflicting the population, with a high incidence and a wide distribution across different age groups. Effectively preventing the occurrence of urinary tract stones is of paramount importance. The primary aim of this study is to investigate the correlations between individual characteristics, water consumption habits, dietary habits, exercise habits, and the occurrence of urinary tract stones in a Taiwanese population. Materials and Methods: This study is cross-sectional research conducted over one month in 2022. One hundred eligible urinary stone cases were recruited through physician screening at outpatient clinics, and an additional one hundred samples from surgical outpatients without urinary tract stones were included as the control group. A questionnaire survey was employed to gather information on demographic variables, dietary habits, water consumption, and exercise habits of the cases. Descriptive statistics, chi-square tests, and logistic regression were used to explore the impact of relevant factors on urinary stone formation. Results: The analysis results revealed that among the demographic variables, males exhibited a higher risk of contracting urinary tract stones than females, and the majority of cases fell within the 40- to 49-year-old age group. Unhealthy lifestyle habits such as smoking and betel nut chewing also demonstrated a higher susceptibility to urinary tract stones. A logistic regression analysis showed that individuals who engaged in physical activity more than three times per week and those with inadequate water intakes had a higher risk of developing urinary tract stones. Conclusions: There is a close relationship between lifestyle and urinary tract stones. It is recommended that individuals continue to hydrate adequately during exercise.

Lifestyle factors, serum parameters, metabolic comorbidities, and the risk of kidney stones: a Mendelian randomization study

Background and objective

The early identification of modifiable risk factors is important for preventing kidney stones but determining causal associations can be difficult with epidemiological data. We aimed to genetically assess the causality between modifiable factors (lifestyle factors, serum parameters, and metabolic comorbidities) and the risk of kidney stones. Additionally, we aimed to explore the causal impact of education on kidney stones and its potential mediating pathways.

Methods

We conducted a two-sample Mendelian randomization (MR) study to explore the causal association between 44 modifiable risk factors and kidney stones. The FinnGen dataset initially explored the causal relationship of risk factors with kidney stones and the UK Biobank dataset was used as the validation set. Then, a meta-analysis was conducted by combining discovery and validation datasets. We used two-step MR to assess potential mediators and their mediation proportions between education and kidney stones.

Results

The combined results indicated that previous exposures may increase the risk of kidney stones, including sedentary behavior, urinary sodium, the urinary sodium/potassium ratio, the urinary sodium/creatinine ratio, serum calcium, 25-hydroxyvitamin D (25OHD), the estimated creatinine-based glomerular filtration rate (eGFRcrea), GFR estimated by serum cystatin C (eGFRcys), body mass index (BMI), waist circumference, type 2 diabetes mellitus (T2DM), fasting insulin, glycated hemoglobin, and hypertension. Coffee intake, plasma caffeine levels, educational attainment, and the urinary potassium/creatinine ratio may decrease the risk of kidney stones. Ranked by mediation proportion, the effect of education on the risk of kidney stones was mediated by five modifiable risk factors, including sedentary behavior (mediation proportion, 25.7%), smoking initiation (10.2%), BMI (8.2%), T2DM (5.8%), and waist circumference (3.2%).

Conclusion

This study provides MR evidence supporting causal associations of many modifiable risk factors with kidney stones. Sedentary lifestyles, obesity, smoking, and T2DM are mediating factors in the causal relationship between educational attainment and kidney stones. Our results suggest more attention should be paid to these modifiable factors to prevent kidney stones.

Oxalate (dys)Metabolism: Person-to-Person Variability, Kidney and Cardiometabolic Toxicity

Oxalate is a metabolic end-product whose systemic concentrations are highly variable among individuals. Genetic (primary hyperoxaluria) and non-genetic (e.g., diet, microbiota, renal and metabolic disease) reasons underlie elevated plasma concentrations and tissue accumulation of oxalate, which is toxic to the body. A classic example is the triad of primary hyperoxaluria, nephrolithiasis, and kidney injury. Lessons learned from this example suggest further investigation of other putative factors associated with oxalate dysmetabolism, namely the identification of precursors (glyoxylate, aromatic amino acids, glyoxal and vitamin C), the regulation of the endogenous pathways that produce oxalate, or the microbiota's contribution to oxalate systemic availability. The association between secondary nephrolithiasis and cardiovascular and metabolic diseases (hypertension, type 2 diabetes, and obesity) inspired the authors to perform this comprehensive review about oxalate dysmetabolism and its relation to cardiometabolic toxicity. This perspective may offer something substantial that helps advance understanding of effective management and draws attention to the novel class of treatments available in clinical practice.

Chemical Studies of Multicomponent Kidney Stones Using the Modern Advanced Research Methods

Defining the kidney stone composition is important for determining a treatment plan, understanding etiology and preventing recurrence of nephrolithiasis, which is considered as a common, civilization disease and a serious worldwide medical problem. The aim of this study was to investigate the morphology and chemical composition of multicomponent kidney stones. The identification methods such as infrared spectroscopy (FTIR), X-ray diffraction (XRD), and electron microscopy with the EDX detector were presented. The studies by the X-ray photoelectron spectroscopy (XPS) were also carried out for better understanding of their chemical structure. The chemical mapping by the FTIR microscopy was performed to show the distribution of individual chemical compounds that constitute the building blocks of kidney stones. The use of modern research methods with a particular emphasis on the spectroscopic methods allowed for a thorough examination of the subject of nephrolithiasis.

Association between added sugars and kidney stones in U.S. adults: data from National Health and Nutrition Examination Survey 2007-2018

Purpose

Added sugar is associated with a variety of adverse health outcomes, but its association with kidney stones is unclear. This study was to determine whether added sugar is associated with kidney stones.

Materials and methods

This nationally representative study used National Health and Nutrition Examination Survey (NHANES) datasets from 2007 to 2018 for analysis. People aged ≥20 years who reported a history of kidney stones and provided dietary recall data on added sugars were included. Weighted proportions, multivariable logistic regression analysis and stratified logistic regression were used to evaluate the associations between added sugars and kidney stones by adjusting potential confounders.

Results

Totally 28,303 adults were included, with weighted mean age [95% confidence interval (CI)] of 48.03 (47.56, 48.51) years, 47.74% (47.09, 48.40%) males and 52.26% (51.60, 52.91%) females. The overall mean (95% CI) energy intake from added sugars was 272.10 (266.59, 277.60) kilocalories. In the fully-adjusted multivariable model, the percentage of energy intake from added sugars was positively correlated with kidney stones. Compared to the first quartile of added sugar energy intake percentage, the population in the fourth quartile had a higher prevalence of kidney stones (OR = 1.39; 95% CI 1.17 to 1.65). Compared with the less than 5% calories from added sugar population, the more than or equal to 25% calories from added sugar had a higher kidney stone prevalence (OR = 1.88; 95% CI 1.52 to 2.32).

Conclusion

A higher percentage of energy intake from added sugars is significantly associated with a higher prevalence of kidney stones. This study provides cross-sectional evidence for the relationship between added sugars and health outcomes.

Machine Learning Models to Predict Kidney Stone Recurrence Using 24 Hour Urine Testing and Electronic Health Record-Derived Features

Objective

To assess the accuracy of machine learning models in predicting kidney stone recurrence using variables extracted from the electronic health record (EHR).

Methods

We trained three separate machine learning (ML) models (least absolute shrinkage and selection operator regression [LASSO], random forest [RF], and gradient boosted decision tree [XGBoost] to predict 2-year and 5-year symptomatic kidney stone recurrence from electronic health-record (EHR) derived features and 24H urine data (n = 1231). ML models were compared to logistic regression [LR]. A manual, retrospective review was performed to evaluate for a symptomatic stone event, defined as pain, acute kidney injury or recurrent infections attributed to a kidney stone identified in the clinic or the emergency department, or for any stone requiring surgical treatment. We evaluated performance using area under the receiver operating curve (AUC-ROC) and identified important features for each model.

Results

The 2- and 5- year symptomatic stone recurrence rates were 25% and 31%, respectively. The LASSO model performed best for symptomatic stone recurrence prediction (2-yr AUC: 0.62, 5-yr AUC: 0.63). Other models demonstrated modest overall performance at 2- and 5-years: LR (0.585, 0.618), RF (0.570, 0.608), and XGBoost (0.580, 0.621). Patient age was the only feature in the top 5 features of every model. Additionally, the LASSO model prioritized BMI and history of gout for prediction.

Conclusions

Throughout our cohorts, ML models demonstrated comparable results to that of LR, with the LASSO model outperforming all other models. Further model testing should evaluate the utility of 24H urine features in model structure.

Effects of Delayed Surgical Intervention Following Emergency Department Presentation on Stone Surgery Complexity

Introduction and Objective: Prior literature had demonstrated increased stone burden and higher rates of staged surgery in individuals of lower socioeconomic status (SES). Low SES individuals are more likely to experience delays in definitive stone surgery after initial presentation to the emergency department (ED) for kidney stones. This study aims to investigate the relationship between delays in definitive kidney stone surgery and the subsequent need for percutaneous nephrolithotomy (PNL) and/or staged surgical procedures using a statewide data set. Methods: This retrospective cohort study gathered longitudinal data from 2009 to 2018 using the California Department of Health Care Access and Information data set. Patient demographic characteristics, comorbidities, diagnosis/procedure codes, and distance were analyzed. Complex stone surgery was defined as initial PNL and/or undergoing more than one procedure within 365 days of initial intervention. Results: A total of 1,816,093 billing encounters from 947,798 patients were screened, resulting in 44,835 patients with ED visits for kidney stones followed by a urologic stone procedure. Multivariable analysis revealed that relative to patients who underwent surgery within 1 month of initial ED visit for stone disease, patients were at increased odds of undergoing complex surgery if waiting ≥6 months (odds ratio [OR] 1.18, p = 0.022), ≥1 year (OR 1.29, p < 0.001), and ≥3 years (OR 1.43, p < 0.001). Conclusions: Delays in definitive stone surgery after initial ED encounter for stone disease were associated with increased likelihood of undergoing a complex stone treatment.

Association between metabolically healthy obesity and kidney stones: results from the 2011-2018 National Health and Nutrition Examination Survey

Introduction

The risk of kidney stones in metabolically healthy obesity (MHO) individuals is largely unexplored. This study using percent body fat (%BF) to categorize obesity, to investigate the association between MHO as well as other metabolic syndrome-obesity combined phenotypes and kidney stones in a national representative population.

Materials and methods

This cross-sectional study included 4,287 participants in the National Health and Nutrition Examination Survey from 2011 to 2018. Metabolically healthy status was defined as not having any component of metabolic syndrome or insulin resistance. Obesity was identified by %BF, which was measured and assessed by dual-energy x-ray absorptiometry (DXA) scan. Participants were cross-classified by metabolic health and obesity status. The outcome was self-report kidney stones. Multivariable logistic regression model was used to examine the association between MHO and kidney stones.

Results

A total of 358 participants had kidney stones [weighted prevalence (SE): 8.61% (0.56%)]. The weighted prevalence (SE) of kidney stones in MHN, MHOW, and MHO groups was 3.13% (1.10%), 4.97% (1.36%), and 8.55% (2.09%), respectively. After adjusting for age, sex, race and ethnicity, education level, smoking status, alcohol consumption, physical activity, daily water intake, CKD stage 3-5, and hyperuricemia, MHO individuals (OR: 2.90, 95% CI: 1.18, 7.0) had a significantly higher risk of kidney stones than those with metabolically healthy normal weight. In metabolically healthy participants, a 5% increment in %BF was associated with a significantly higher risk of kidney stones (OR: 1.60, 95% CI: 1.20, 2.14). Furthermore, a nonlinear dose-response relationship between %BF and the kidney stones was observed in metabolically healthy participants (P for non-linearity = 0.046).

Conclusion

Using %BF to define obesity, MHO phenotype was significantly associated with higher risks of kidney stones, suggesting that obesity can independently contribute to kidney stones in the absence of metabolic abnormalities and insulin resistance. Regarding kidney stones prevention, MHO individuals might still benefit from lifestyle interventions aimed at healthy body composition maintenance.

Insights into risk factors for urolithiasis: a mendelian randomization study

BACKGROUND

Risk factors for urolithiasis have not been identified. Here, we aimed to identify potentially causal risk factors driving the risk of urolithiasis.

METHODS

Two sets of instrumental variables were used for analysis, derived from publicly available databases. Summary-level statistical data for urolithiasis were obtained from the MRC-IEU Consortium and UK biobank (Neale Lab). Mendelian randomization (MR) was conducted to identify causal risk of urolithiasis. Finally, the results of the two databases were combined and a meta-analysis was performed.

RESULTS

In the MRC-IEU consortium, the odds of urolithiasis increased per 1-SD increase of body mass index (BMI) (OR = 1.0016, 95% CI:1.0004-1.0029, p = 0.010), triglycerides (OR = 1.0016, 95% CI:1.0003-1.0029, p = 0.017), adiponectin (OR = 1.0027, 95% CI:1.0003-1.0050, p = 0.024), and body fat percentage (OR = 1.008, 95% CI:1.0001-1.0161, p = 0.047). In addition, alcohol intake also increased the incidence of urolithiasis (OR = 1.0030, 95% CI:1.0009-1.0051, p = 0.005). In the UK biobank, the odds of urolithiasis increased per 1-SD increase of waist circumference (OR = 1.0215, 95% CI:1.0061-1.0372, p = 0.008) and body fat percentage (OR = 1.0239, 95% CI:1.0043-1.0440, p = 0.020). Surprisingly, we found that the risk of urolithiasis decreased with increasing hip circumference (OR = 0.9954, 95% CI:0.9915-0.9992, p = 0.017). In a meta-analysis of MR results, higher BMI (OR = 1.0016, 95% CI:1.0004-1.0027, p = 0.009), waist circumference (OR = 1.0073, 95% CI:1.0020-1.0126, p = 0.007), adiponectin (OR = 1.0026, 95% CI:1.0008-1.0043, p = 0.004), triglycerides (OR = 1.0015, 95% CI:1.0004-1.0026, p = 0.008) and body fat percentage (OR = 1.0104, 95% CI:1.0030-1.0178, p = 0.006) increased the risk of urolithiasis. Furthermore, alcohol intake also increased the incidence of urolithiasis (OR = 1.0033, 95% CI:1.0012-1.0053, p = 0.002).

CONCLUSIONS

Our MR study found that higher BMI, triglycerides, waist circumference, adiponectin, body fat percentage, and alcohol intake increased the risk of urolithiasis.

Kidney Stone Prevention

Kidney stone disease (KSD) (alternatively nephrolithiasis or urolithiasis) is a global health care problem that affects almost people in developed and developing countries. Its prevalence has been continuously increasing with a high recurrence rate after stone removal. Although effective therapeutic modalities are available, preventive strategies for both new and recurrent stones are required to reduce physical and financial burdens of KSD. To prevent kidney stone formation, its etiology and risk factors should be first considered. Low urine output and dehydration are the common risks of all stone types, whereas hypercalciuria, hyperoxaluria, and hypocitraturia are the major risks of calcium stones. In this article, up-to-date knowledge on strategies (nutrition-based mainly) to prevent KSD is provided. Important roles of fluid intake (2.5-3.0 L/d), diuresis (>2.0-2.5 L/d), lifestyle and habit modifications (for example, maintain normal body mass index, fluid compensation for working in high-temperature environment, and avoid cigarette smoking), and dietary management [for example, sufficient calcium at 1000-1200 mg/d, limit sodium at 2 or 3-5 g/d of sodium chloride (NaCl), limit oxalate-rich foods, avoid vitamin C and vitamin D supplements, limit animal proteins to 0.8-1.0 g/kg body weight/d but increase plant proteins in patients with calcium and uric acid stone and those with hyperuricosuria, increase proportion of citrus fruits, and consider lime powder supplementation] are summarized. Moreover, uses of natural bioactive products (for example, caffeine, epigallocatechin gallate, and diosmin), medications (for example, thiazides, alkaline citrate, other alkalinizing agents, and allopurinol), bacterial eradication, and probiotics are also discussed. Adv Nutr 2023;x:xx-xx.