Incident Stones Research Articles

Dietary Risk Factors for Incident and Recurrent Symptomatic Kidney Stones

ObjectiveTo compare dietary factors between incident symptomatic stone formers and controls, and among the incident stone formers, to determine whether dietary factors were predictive of symptomatic recurrence. Patients and MethodsWe prospectively recruited 411 local incident symptomatic kidney stone formers (medical record validated) and 384 controls who were seen at Mayo Clinic in Minnesota or Florida between January 1, 2009, and August 31, 2018. Dietary factors were based on a Viocare, Inc, food frequency questionnaire administered during a baseline in-person study visit. Logistic regression compared dietary risk factors between incident symptomatic stone formers and controls. Incident stone formers were followed up for validated symptomatic recurrence in the medical record. Cox proportional hazards models estimated risk of symptomatic recurrence with dietary factors. Analyses adjusted for fluid intake, energy intake, and nondietary risk factors. ResultsIn fully adjusted analyses, lower dietary calcium, potassium, caffeine, phytate, and fluid intake were all associated with a higher odds of an incident symptomatic kidney stone. Among incident stone formers, 73 experienced symptomatic recurrence during a median 4.1 years of follow-up. Adjusting for body mass index, fluid intake, and energy intake, lower dietary calcium and lower potassium intake were predictive of symptomatic kidney stone recurrence. With further adjustment for nondietary risk factors, lower dietary calcium intake remained a predictor of recurrence, but lower potassium intake only remained a predictor of recurrence among those not taking thiazide diuretics or calcium supplements. ConclusionEnriching diets in stone formers with foods high in calcium and potassium may help prevent recurrent symptomatic kidney stones.

Factors associated with sex differences in the risk of kidney stones.

Men are at higher risk of developing stones compared with women; however, recent data suggest a changing epidemiology, with women being relatively more affected than before. To estimate the proportion of excess risk among men, we analysed data from large cohorts (Health Professionals Follow-up Study and Nurses' Health Study I and II). Kidney stone incidence rates were computed and hazard ratios (HRs) and 95% confidence intervals (CIs) generated with age-adjusted Cox proportional regression models. Mediation analysis estimated the excess risk for men explained by risk factors, including waist circumference, high blood pressure, diabetes, use of thiazides and dietary intake. The 24-h urine composition was also examined. The analysis included 268553 participants, contributing 5 872 249 person-years of follow-up. A total of 10 302 incident stones were confirmed and the overall incidence rate was 271 and 159 per 100 000 person-years for men and women, respectively. The age-adjusted HR was 2.32 (95% CI 2.20, 2.45) and the risk of stones was consistently higher across categories of age (HRs ranging from 2.02 to 2.76) for men compared with women. The risk remained higher among men, but tended to decrease over time (48.1%), while it increased among women. Urine supersaturations for calcium oxalate and uric acid were higher among men, primarily because of higher oxalate (26.3%), uric acid (16.3%), phosphate (23.5%) and lower pH. The risk of kidney stones is higher among men and this difference is only partly explained by lifestyle risk factors; differences in urine chemistries explain a substantial fraction of the excess risk.

MO122SEX DIFFERENCES IN THE RISK OF KIDNEY STONES

Abstract Background and Aims Kidney stone disease is a highly prevalent condition. Men are at higher risk of developing stones compared with women, however recent data suggest a changing epidemiology with women being relatively more affected than in the past. The reasons for such differences and changes over time are not clear. Method We analyzed the association between sex and the first symptomatic incident kidney stone using data from three large, longitudinal cohorts. Incidence rates for men and women overall and across categories of age and calendar time were computed and hazard ratios (HRs) and 95% confidence intervals (CIs) generated with age-adjusted Cox proportional hazards regression models. Mediation analysis was performed in order to estimate the amount of excess risk for men explained by established risk factors, including BMI, waist circumference, history of high blood pressure, history of diabetes, use of thiazides, dietary intakes of animal protein, caffeine, fructose, potassium, sodium, oxalate, phytate, dietary and supplemental intakes of calcium, vitamin C and vitamin D, sugar-sweetened beverages and total fluid intake. Results The analysis included data from 268,616 participants, contributing 5,876,205 person-years of follow-up, during which 10,303 incident stone events were confirmed. The overall incidence rate of kidney stones was 271 and 158 per 100,000 person-years for men and women, respectively. The age-adjusted HR for men compared with women was 2.32 (95% CI 2.20, 2.45). About 18% of the difference in rates was explained by the risk factors included in the analysis. The risk of stones was consistently higher across categories of age among men compared with women. With regard to calendar time, the risk remained higher among men, but tended to decrease over time while it increased among women, resulting in a relative risk reduction of 38% for after 2009 compared with before 1990. Conclusion The risk of kidney stones is higher among men compared with women. This difference is only partly explained by modifiable risk factors.

Beyond Prevalence: Annual Cumulative Incidence of Kidney Stones in the United States.

It is well documented that the prevalence of nephrolithiasis is increasing in adults in the United States over time. Approximately 11% of men and 7% of women have reported a lifetime history of nephrolithiasis in cross-sectional studies. However, the burden of acute management may be better assessed from annual cumulative incidence. This accounting of new stone occurrences, however, is not well described on a national scale. The Medical Expenditure Panel Survey is a set of large-scale health care utilization surveys of families, individuals, their health care providers and employers, with surveys administered every 6 months for the duration of each individual's 2-year panel. We queried the survey data of adult participants between 2005 and 2015, with analysis conducted with provided weights and strata to allow our findings to be representative of the civilian noninstitutionalized U.S. adult population. Those with diagnosed renal or ureteral calculi as noted by ICD-9 codes were included as our incident stone formers. In 2005, the mean age of stone formers was 45 years. Of stone formers 52.2% were male, 91% were White and 47.6% were in the Southern U.S. The incidence of stone occurrences was 0.6% (177/33,961 individuals, weighted to represent population of 1,923,322/296,185,002 individuals). By 2015, the mean age was 51.7 years, with 52% male, 83% White and 38.2% residing in the Southern U.S. Between 2005 and 2015, the overall incidence increased from 0.6% to 0.9% (p <0.001). Based on this large-scale, nationally representative analysis of adults in the United States, the estimated annual cumulative incidence of stone occurrence is approaching 1%. Moreover, this incidence appears to be increasing over time, rising from 0.6% in 2005 to 0.9% in 2015. These data may help to better anticipate the need for urological care for stone disease and direct resource distribution.

Risk of chronic kidney disease in patients with kidney stones\u2014a nationwide cohort study

BackgroundChronic kidney disease (CKD) and kidney stones are common in Taiwan; in particular, CKD has a high prevalence but low self-awareness rate. CKD-related risk factors such as diabetes, hypertension, and nephrotoxic drugs are well-known and uncontested; however, kidney stones are relatively less studied and easily overlooked as a risk factor. The objective of this study was to investigate whether kidney stones are a risk factor for CKD.MethodsWe conducted a nationwide population-based matched cohort study to assess the risk of incident CKD in people with kidney stones. Data on incident stones formers in the year 2001—excluding those with a history of CKD—were obtained from Taiwan’s National Health Insurance database. Stone formers were matched (1:4) to control subjects according to sex, age, and index date. The total observation period of the study was 10 years, and the primary end-point was the occurrence of CKD. Student’s t-test and Chi-squared test were used to compare continuous and categorical data, respectively. Logistic regression was used to calculate the odds ratio of kidney stone patients with incident CKD relative to the control group. Cox proportional hazard regression model was used to obtain the hazard ratio for development of incident CKD among patients with kidney stones.ResultsThe incidence of CKD in the kidney stone cohort was 11.2%, which was significantly higher than that of the control group (P < .001). Survival analysis showed that the stones cohort was 1.82 times more likely to experience CKD than the controls. Age, sex, hypertension, diabetes mellitus, and hyperlipidemia increased the risk of CKD incidence (1.04, 1.27, 1.55, 3.31, and 1.25 times, respectively).ConclusionKidney stones are a definite risk factor for CKD; therefore, patients with stones are suggested to undergo regular renal function monitoring and receive appropriate treatment to avoid CKD.

Dietary and lifestyle factors for primary prevention of nephrolithiasis: a systematic review and meta-analysis

BackgroundDietary and lifestyle factors may play an important role in the increasing prevalence of nephrolithiasis. We aimed to review and quantify the associations between lifestyle factors and incident nephrolithiasis and suggest lifestyle changes for the primary prevention of nephrolithiasis.MethodsPubMed, EMBASE, and Cochrane Library were searched up to May 2019, for observational studies and randomized controlled trials (RCTs) that assessed modifiable lifestyle factors and risk of nephrolithiasis in adults. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were computed using a random effects model. The I2 statistic was employed to evaluate heterogeneity. Subgroup analysis, sensitivity analysis and meta-regression were also conducted whenever possible.ResultsFifty relevant articles with 1,322,133 participants and 21,030 cases in total were identified. Prominent risk factors for incident stones were body mass index (1.39,1.27–1.52), dietary sodium (1.38, 1.21–1.56), fructose, meat, animal protein, and soda. In contrast, protective factors included fluid intake (0.55, 0.51–0.60), a Dietary Approaches to Stop Hypertension (DASH) style diet (0.69, 0.64–0.75), alcohol (0.69, 0.56–0.85), water, coffee, tea, vegetables, fruits, dietary fiber, dietary calcium (0.83, 0.76–0.90), and potassium. Vitamin D (1.22, 1.01–1.49) and calcium (1.16, 1.00–1.35) supplementation alone increased the risk of stones in meta-analyses of observational studies, but not in RCTs, where the cosupplementation conferred significant risk.ConclusionsSeveral modifiable factors, notably fluid intake, dietary patterns, and obesity, were significantly associated with nephrolithiasis. Long-term RCTs are required to investigate the cost-effectiveness of dietary patterns for stone prevention. The independent and combined effects of vitamin D and calcium supplementation on nephrolithiasis need further elucidation.

Analysis of the Structure of Cellulose Fibers Using the Imagej Program and Fibercement Properties on their Basis

This article presents the results of an experimental study of the effect of morphometric parameters of secondary cellulose fiber from various brands of waste paper on the strength characteristics of cement stone. The article is based on the results of determining the morphometric parameters of cellulose fibers. Visual analysis of microphotographs of cellulosic fibers showed that the smallest fractions of fibers were obtained from newspaper waste paper of grade MS-8V. A causal relationship has been established between the fiber content and the strength of an incident stone. It was found that samples with a content of cellulose fibers of 0.5-0.75% of the mass of cement have high strength. The most durable were samples with the addition of cellulosic fibers based on newspaper recycled paper MS-8V.

Stone recurrence among childhood kidney stone formers: results of a nationwide study in Iceland.

To examine the stone recurrence rate among childhood kidney stone formers in the Icelandic population. We retrospectively examined kidney stone recurrence in a recently reported population-based sample of 190 individuals who experienced their first stone before 18years of age in the period 1985-2013. Of these 190 individuals, 112 (59%) were females and the median (range) age at the incident stone diagnosis was 15.0 (0.2-17.9) years. Stone recurrence was defined as an acute symptomatic episode with imaging confirmation or self-reported stone passage, new stone detected by imaging in asymptomatic patients, and suspected clinical stone episode without verification. The Kaplan-Meier method was used to assess stone-free survival and the Chi-square, Fisher's exact, Wilcoxon rank-sum and the log-rank tests to compare groups. A total of 68 (35%) individuals experienced a second stone event, 1.7 (0.9-18.9) years after the initial diagnosis. The recurrence rate was 26%, 35%, 41% and 46% after 5, 10, 15 and 20years of follow-up, respectively. The 5-year recurrence rate increased with time and was 9%, 24% and 37% in the periods 1985-1994, 1995-2004 and 2005-2013, respectively (P = 0.005). No difference in stone recurrence was observed between the sexes (P = 0.23). In our population-based sample of childhood kidney stone formers, the stone recurrence rate is similar to that reported for adults. The observed rise in stone recurrence with time may be related to closer patient follow-up in recent years or increased stone risk in general.

Are upper urinary tract stones more common in more deprived populations?

Purpose: To examine the relationship between deprivation and upper tract calculus formation, and provide a contemporary estimate of the incidence of upper urinary tract stone disease. Methods: A retrospective review of hospital episodes for patients presenting to our institution with upper urinary tract stone disease in a 3-year period between 2010 and 2014. Incidence of stone disease was calculated and stratified according to deprivation, as measured by the index of multiple deprivation (IMD) and its subdomains. Poisson regression was used to model the relationship between deprivation and stone disease. Results: The overall incidence of upper urinary tract stone disease was 115 patients/100,000 person-years (95% confidence interval (CI) 108–122 per 100,000 person-years). There is a link between the IMD (as well as a number of its subdomains) and stone disease. The rate of incident stone disease was 50.6% higher in the most deprived quintile of the IMD when compared to the least deprived ( p &lt; 0.001). Multivariate Poisson regression found that education, skills and training deprivation was the subdomain that predicted stone disease most strongly, with the incidence rate ratio being 1.15 (95% CI 1.053–1.261) for each increase in quintile. Conclusion: This study provides a contemporary measure of the incidence of upper urinary tract stone disease derived from a population in the Midlands of England. It informs our understanding of the link between types of deprivation and stone occurrence. Level of evidence: 2b

Antibiotic Use and Risk of Incident Kidney Stones in Female Nurses

The intestinal microbiome may affect urinary stone disease by modulating the amount of oxalate absorbed from the intestine and subsequently excreted in urine. This study sought to explore the association between antibiotics, which alter the intestinal microbiota, and risk for urinary stone disease. Prospective cohort study. 5,010 women in the Nurses' Health Study (NHS) I and II who had collected 24-hour urine samples. Use of antibiotics during the age range of 40 to 49 (NHS II), 40 to 59 (NHS I), and 20 to 39 years (both cohorts). Incident symptomatic urinary stone disease; urine composition. Cause-specific hazards regression adjusted for age, body mass index, comorbid conditions, thiazide use, and dietary factors. Follow-up was censored at the time of asymptomatic kidney stones, cancer, or death. Cumulative use of antibiotics for a total of 2 or more months during the age range of 40 to 49 years (NHS II) and 40 to 59 years (NHS II) was associated with significantly higher risk for developing incident stones compared with no use (pooled HR, 1.48; 95% CI, 1.12-1.96). Similar results were found for the period of 20 to 39 years (pooled HR, 1.36; 95% CI, 1.00-1.84). Results were unchanged after excluding participants who reported urinary tract infection with their stone event or as the most common reason for antibiotic use. Urine composition was generally similar across antibiotic groups except for marginally lower urine pH and citrate values among those taking antibiotics for 2 or more months. Observational design; lack of information for type of antibiotic used; relatively large span of time between antibiotic use and urine collection. Use of antibiotics for more than 2 months in early adulthood and middle age is associated with higher risk for urinary stone disease in later life.

Plant and Animal Protein Intake and Risk of Incident Kidney Stones: Results from the Shanghai Men's and Women's Health Studies.

High animal protein intake is a risk factor for nephrolithiasis. Whether plant based sources of protein are associated with kidney stone risk is not well studied. We examined the association of animal and plant protein intake with the risk of incident kidney stones in Shanghai, China. Dietary intakes were obtained from a validated food frequency questionnaire at baseline. Self-reported stone events were ascertained at baseline and at followup visits. Multivariable Cox regression models were used to evaluate the associations of protein intake with the incident stone risk. During 319,211 and 696,950 person-years of followup 1,451 men and 1,202 women, respectively, reported incident stones. The average ± SD intake of animal and plant protein standardized to 2,000 kcal was 31.3 ± 13.7 and 48.4 ± 7.2 gm per day in women, and 30.8 ± 13.3 and 51.3 ± 7.6 gm per day, respectively, in men. On multivariable analysis participants in the highest quintiles of animal and nondairy animal protein intake showed an increased risk of incident stones compared to those in the lowest quintiles (HR 1.16, 95% CI 1.01-1.32, p=0.03 vs HR 1.14, 95% CI 1.01-1.30, p=0.04). Compared to the lowest quintile the highest intake quintiles of the animal-to-plant protein ratios and the nondairy animal-to-plant protein ratios were positively associated with stone risk (HR 1.17, 95% CI 1.03-1.33, p=0.02 and HR 1.20, 95% CI 1.06-1.36, p=0.005, respectively). No association was observed with plant protein intake (ptrend=0.14). In this population with a relatively low animal protein intake and a high plant protein intake, a greater animal protein intake was associated with a kidney stone risk. Increasing the proportion of plant protein relative to animal protein appeared protective against the risk.

A preliminary survey of practice patterns across several European kidney stone centers and a call for action in developing shared practice.

Currently an evidence-based approach to nephrolithiasis is hampered by a lack of randomized controlled trials. Thus, there is a need for common platforms for data sharing and recruitment of patients to interventional studies. A first step in achieving this objective would be to share practice methods and protocols for subsequent standardization in what is still a heterogeneous clinical field. Here, we present the results of a pilot survey performed across 24 European clinical kidney stone centers. The survey was distributed by a voluntary online questionnaire circulated between June 2017 and January 2018. About 46% of centers reported seeing on average 20 or more patients per month. Only 21% adopted any formal referral criteria. Centers were relatively heterogeneous in respect of the definition of an incident stone event. The majority (71%) adopted a formal follow-up scheme; of these, 65% included a follow-up visit at 3 and 12 months, and 41% more than 12 months. In 79% of centers some kind of imaging was performed systematically. 75% of all centers performed laboratory analyses on blood samples at baseline and during follow-up. All centers performed laboratory analyses on 24-h urine samples, the majority (96%) at baseline and during follow-up. There was good correspondence across centers for analyses performed on 24-h urine samples, although the methods of 24-h urine collection and analysis were relatively heterogeneous. Our survey among 24 European stone centers highlights areas of homogeneity and heterogeneity that will be investigated further. Our aim is the creation of a European network of stone centers sharing practice patterns and hosting a common database for research and guidance in clinical care.

Green tea intake and risk of incident kidney stones: Prospective cohort studies in middle-aged and elderly Chinese individuals.

To investigate the association between green tea intake and incident stones in two large prospective cohorts. We examined self-reported incident kidney stone risk in the Shanghai Men's Health Study (n=58054; baseline age 40-74years) and the Shanghai Women's Health Study (n=69166; baseline age 40-70years). Information on the stone history and tea intake was collected by in-person surveys. Multivariable Cox proportional hazards models were adjusted for baseline demographic variables, medical history and dietary intakes including non-tea oxalate from a validated food frequency questionnaire. During 319211 and 696950 person-years of follow up, respectively, 1202 men and 1451 women reported incident stones. Approximately two-thirds of men and one-quarter of women were tea drinkers at baseline, of whom green tea was the primary type consumed (95% in men, 88% in women). Tea drinkers (men: hazard ratio 0.78, 95% confidence interval 0.69-0.88; women: hazard ratio 0.8, 95% confidence interval 0.77-0.98) and specifically green tea drinkers (men: hazard ratio 0.78, 95% confidence interval 0.69-0.88; women: hazard ratio 0.84, 95% confidence interval 0.74-0.95) had lower incident risk than never/former drinkers. Compared with never/former drinkers, a stronger dose-response trend was observed for the amount of dried tea leaf consumed/month by men (hazard ratiohighest category 0.67, 95% confidence interval 0.56-0.80, Ptrend <0.001) than by women (hazard ratiohighest category 0.87, 95% confidence interval 0.70-1.08, Ptrend =0.041). Green tea intake is associated with a lower risk of incident kidney stones, and the benefit is observed more strongly among men.

Menopause and Risk of Kidney Stones

Metabolic changes due to menopause may alter urine composition and kidney stone risk but results of prior work on this association have been mixed. We examined menopause and the risk of incident kidney stones, and changes in 24-hour urine composition in the NHS (Nurses' Health Study) II. Using multivariate adjusted Cox proportional hazards models we prospectively analyzed 108,639 NHS II participants who provided information on menopause and kidney stones. We also analyzed 24-hour urine collections from 658 participants who performed a collection while premenopausal and a repeat collection after menopause. During 22 years of followup there were 3,456 incident kidney stones. The multivariate adjusted relative risk of an incident kidney stone in postmenopausal participants compared with premenopause was 1.27 (95% CI 1.08-1.46). On stratified analysis compared with premenopause the multivariate adjusted relative risk of natural and surgically induced menopause was 1.27 (95% CI 1.09-1.48) and 1.43 (95% CI 1.19-1.73), respectively. Among the 74,505 postmenopausal participants there was a total of 1,041 incident stone events. Compared with no hormone therapy neither current nor past use was significantly associated with kidney stone risk. Compared with premenopause the postmenopausal urine collections had lower mean calcium, citrate, phosphorus and uric acid, and higher mean volume. Postmenopausal status is associated with a higher risk of incident kidney stones. Natural menopause and surgical menopause are independently associated with higher risk. There are small but significant differences in urine composition between premenopausal and postmenopausal urine collections.

PD17-02 GREEN TEA INTAKE AND RISK OF INCIDENT KIDNEY STONES: A REPORT FROM THE SHANGHAI MEN’S AND WOMEN’S HEALTH STUDIES

You have accessJournal of UrologyStone Disease: Medical & Dietary Therapy I1 Apr 2018PD17-02 GREEN TEA INTAKE AND RISK OF INCIDENT KIDNEY STONES: A REPORT FROM THE SHANGHAI MEN’S AND WOMEN’S HEALTH STUDIES Xiang Shu, Hui Cai, Yong-Bing Xiang, Honglan Li, Loren Lipworth, Nicole Miller, Wei Zheng, Xiao-Ou Shu, and Ryan Hsi Xiang ShuXiang Shu More articles by this author , Hui CaiHui Cai More articles by this author , Yong-Bing XiangYong-Bing Xiang More articles by this author , Honglan LiHonglan Li More articles by this author , Loren LipworthLoren Lipworth More articles by this author , Nicole MillerNicole Miller More articles by this author , Wei ZhengWei Zheng More articles by this author , Xiao-Ou ShuXiao-Ou Shu More articles by this author , and Ryan HsiRyan Hsi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.964AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Tea intake may increase kidney stone risk as a source of dietary oxalate, but as a fluid it may also decrease risk. Previous studies investigating the association of tea intake and risk of stones have had mixed results. However, these studies primarily evaluated black tea, which has the highest oxalate content among different tea types. Green tea has inhibitory, antioxidative effects on calcium urinary stone formation in animal models. Our study objective was to investigate the association of green tea and incident kidney stones in two large prospective cohorts in Shanghai, China. METHODS We examined self-reported incident kidney stone risk in the Shanghai Men's Health Study (N=58,054 men; baseline age range 40-74) and the Shanghai Women's Health Study (N =69,166 women; baseline age range 40-70 years) who had no history of nephrolithiasis at study enrollment. Information on kidney stone history and tea intake was collected by in-person surveys. Multivariable Cox proportional hazards models were adjusted for baseline demographic variables, medical history, smoking history, total energy intake, and dietary intakes of non-tea oxalate, protein, potassium, magnesium, dietary calcium, supplemental calcium and vitamin C assessed using a validated food frequency questionnaire. RESULTS During 319,211 and 696,950 person-years of follow-up, respectively, 1,451 men and 1,202 women reported incident kidney stones. Nearly two-thirds of men and approximately one in four women were self-reported current tea drinkers. Green tea was the primary type consumed in both genders (95% in men and 88% in women). Current tea drinkers had lower incident stone risk than never/former tea drinkers (Men: HR=0.88, 95% CI 0.83-0.94; Women: HR=0.93, 95% CI 0.88-0.99). Compared to never/former tea drinkers, green tea intake was associated with lower risk among both men (HR=0.78, 95% CI 0.69-0.89) and women (HR=0.84, 95% CI 0.74-0.95). Compared to never/former tea drinkers, a stronger dose-response trend was observed for the amount of dried tea leaf consumed/month in men (HR=0.85, 95% CI 0.73-0.99 for <100g; HR=0.82, 95% CI 0.70-0.96 for 100-150g; HR=0.67, 95% CI 0.56-0.80 for>150g; ptrend <0.001) than in women (HR=0.89, 95% CI 0.77-1.02 for <100g; HR=0.82, 95% CI 0.63-1.06 for 100-150g; HR=0.87, 95% CI 0.70-1.08 for >150g; ptrend=0.038). CONCLUSIONS Green tea intake is associated with lower risk of incident kidney stones among the middle-aged and elderly urban Chinese. The benefit of tea intake for reducing stone risk is observed more strongly in men than in women. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e384 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Xiang Shu More articles by this author Hui Cai More articles by this author Yong-Bing Xiang More articles by this author Honglan Li More articles by this author Loren Lipworth More articles by this author Nicole Miller More articles by this author Wei Zheng More articles by this author Xiao-Ou Shu More articles by this author Ryan Hsi More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Intake of Trace Metals and the Risk of Incident Kidney Stones

The association between the intake of trace metals and the risk of incident stones has not been longitudinally investigated. We performed a prospective analysis of 193,551 participants in the Health Professionals Follow-up Study, and the Nurses' Health Study I and II. During a followup of 3,316,580 person-years there was a total of 6,576 incident stones. We used multivariate regression models to identify associations of the intake of zinc, iron, copper and manganese with the risk of stones. In a subset of participants with 24-hour urine collections we examined the association between the intake of trace metals and urine composition. After multivariate adjustment total and dietary intakes of zinc and iron were not significantly associated with incident stones. A higher intake of manganese was associated with a lower risk of stones. The pooled HR of the highest quintile of total manganese intake compared with the lowest intake was 0.82 (95% CI 0.68-0.98, p = 0.02). Total but not dietary copper intake was marginally associated with a higher risk of stones (pooled HR 1.14, 95% CI 1.02-1.28, p = 0.01). There were no statistically significant associations of the total intake of manganese and copper with urinary supersaturation. Zinc and iron intake was not associated with a risk of stones. Copper intake may be associated with a higher risk in some individuals. Higher total manganese intake was associated with a lower risk of stones but not with traditional 24-hour urinary composite markers of stone risk. Further research is needed to elucidate the mechanisms by which manganese may reduce kidney stone formation.

Nephrolithiasis Among Middle Aged and Elderly Urban Chinese: A Report from Prospective Cohort Studies in Shanghai.

Kidney stone risk factors are understudied among Asians. Our study objective was to investigate associations of obesity and other chronic diseases with incident kidney stones among the urban Chinese. Included in this study are two prospective cohorts: the Shanghai Women's Health Study (N = 69,166) and Shanghai Men's Health Study (N = 58,054). Incident kidney stones were determined by self-report in 2004 and 2008. Cox regression models were used to evaluate the associations of study variables with stone risk with adjustment of demographics, medical history, and dietary intakes. There were 2653 incident stones over 1,007,958 person-years of follow-up. Overall incidence rates (per 1000 person-years, 95% confidence interval [CI]) were 2.10 (1.99, 2.21) among women and 3.80 (3.59, 4.02) among men. Higher body mass index (BMI) was associated with risk (BMI ≥25 vs 18.5-24.9 kg/m2, women: hazard ratio [HR] = 1.14 [95% CI 1.01, 1.28]; men: HR = 1.17 [1.03, 1.32]). High waist-hip ratio (≥0.80 and ≥0.90 for women and men, respectively) was associated with risk (HR 1.13, 95% CI 1.01, 1.27 for women; HR 1.19, 95% CI 1.05, 1.35 for men). Coronary heart disease or stroke history was associated with risk in women only (HR 1.31, 95% CI 1.10, 1.56). Hypertension history was associated with risk in men only (HR 1.27, 95% CI 1.11, 1.45). No significant association with diabetes mellitus was observed. Among the Chinese, kidney stone incidence in men is almost twice that of women. Obesity is a shared risk factor. Hypertension history is associated with risk in men, whereas history of coronary heart disease or stroke is associated with risk in women.

Vitamin B6 intake and the risk of incident kidney stones.

Higher vitamin B6 intake might reduce urinary excretion of oxalate, one of the major determinants of risk for calcium oxalate kidney stones. Previous studies investigating the association between intake of vitamin B6 and risk of stones found conflicting results. We sought to investigate the association in three large prospective cohorts. We prospectively examined the association in the Health Professionals Follow-up Study (HPFS; n=42,919 men), Nurses' Health Study I (NHS I; n=60,003 older women), and Nurses' Health Study II (NHS II; n=90,629 younger women). Hazard ratios (HRs) and 95% confidence intervals (CIs) for incident stones across categories of total vitamin B6 intake (<3.0, 3.0-4.9, 5.0-9.9, 10.0-39.9, ≥40.0mg/day) were generated with Cox proportional hazards regression models adjusted for potential confounders. During 3,316,846 person-years of follow-up, 6576 incident kidney stones were confirmed. In univariate and multivariate analyses, there was no association between intake of vitamin B6 and incident stones. The HR for stones in the highest category compared with the lowest was 1.05 (95% CI 0.85, 1.30; p value for trend=0.61) for HPFS, 0.95 (95% CI 0.76, 1.18; p value for trend=0.42) for NHS I, and 1.06 (95% CI 0.91, 1.24; p value for trend=0.34) for NHS II. The pooled adjusted HR for the highest category compared with the lowest was 1.03 (95% CI 0.92, 1.15; p value for trend=0.60). Intake of vitamin B6 is not associated with risk of incident kidney stones.

Low Bone Density and Bisphosphonate Use and the Risk of Kidney Stones.

Previous studies have demonstrated lower bone density in patients with kidney stones, but no longitudinal studies have evaluated kidney stone risk in individuals with low bone density. Small studies with short follow-up reported reduced 24-hour urine calcium excretion with bisphosphonate use. We examined history of low bone density and bisphosphonate use and the risk of incident kidney stone as well as the association with 24-hour calcium excretion. We conducted a prospective analysis of 96,092 women in the Nurses' Health Study II. We used Cox proportional hazards models to adjust for age, body mass index, thiazide use, fluid intake, supplemental calcium use, and dietary factors. We also conducted a cross-sectional analysis of 2294 participants using multivariable linear regression to compare 24-hour urinary calcium excretion between participants with and without a history of low bone density, and among 458 participants with low bone density, with and without bisphosphonate use. We identified 2564 incident stones during 1,179,860 person-years of follow-up. The multivariable adjusted relative risk for an incident kidney stone for participants with history of low bone density compared with participants without was 1.39 (95% confidence interval [95% CI], 1.20 to 1.62). Among participants with low bone density, the multivariable adjusted relative risk for an incident kidney stone for bisphosphonate users was 0.68 (95% CI, 0.48 to 0.98). In the cross-sectional analysis of 24-hour urine calcium excretion, the multivariable adjusted mean difference in 24-hour calcium was 10 mg/d (95% CI, 1 to 19) higher for participants with history of low bone density. However, among participants with history of low bone density, there was no association between bisphosphonate use and 24-hour calcium with multivariable adjusted mean difference in 24-hour calcium of -2 mg/d (95% CI, -25 to 20). Low bone density is an independent risk factor for incident kidney stone and is associated with higher 24-hour urine calcium excretion. Among participants with low bone density, bisphosphonate use was associated with lower risk of incident kidney stone but was not independently associated with 24-hour urine calcium excretion.

Dietary and Lifestyle Risk Factors Associated with Incident Kidney Stones in Men and Women

Several dietary and lifestyle factors are associated with a higher risk of kidney stones. We estimated the population attributable fraction and the number needed to prevent for modifiable risk factors, including body mass index, fluid intake, DASH (Dietary Approaches to Stop Hypertension) style diet, dietary calcium intake and sugar sweetened beverage intake. We used data on the HPFS (Health Professionals Follow-Up Study) cohort and the NHS (Nurses' Health Study) I and II cohorts. Information was obtained from validated questionnaires. Poisson regression models adjusted for potential confounders were used to estimate the association of each risk factor with the development of incident kidney stones and calculate the population attributable fraction and the number needed to prevent. The study included 192,126 participants who contributed a total of 3,259,313 person-years of followup, during which an incident kidney stone developed in 6,449 participants. All modifiable risk factors were independently associated with incident stones in each cohort. The population attributable fraction ranged from 4.4% for a higher intake of sugar sweetened beverages to 26.0% for a lower fluid intake. The population attributable fraction for all 5 risk factors combined was 57.0% in HPFS, 55.2% in NHS I and 55.1% in NHS II. The number needed to prevent during 10 years ranged from 67 for lower fluid intake to 556 for lower dietary calcium intake. Five modifiable risk factors accounted for more than 50% of incident kidney stones in 3 large prospective cohorts. Assuming a causal relation, our estimates suggest that preventive measures aimed at reducing those factors could substantially decrease the burden of kidney stones in the general population.