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  1. 1. EMBARGOED FOR RELEASE UNTIL TUESDAY, MAY 17, 2011 AT 8:00 A.M.Contact: Wendy Waldsachs Isett, AUA410-977-4770, wisett@AUAnet.org RESEARCHERS FIND NEW TIES BETWEEN KIDNEY STONE RISK, TREATMENT AND DIET, STATINS AND BODY FAT DISTRIBUTIONWashington, DC, May 17, 2011– A series of studies that examine the relationship of diet, obesity,nutrition and statin medications will be presented to media at a special press conference during the 2011Annual Meeting of the American Urological Association (AUA). The event will be held in the AUA PressSuite at the Walter E. Washington Convention Center on Wednesday, May 18, 2011 at 8 a.m. EDT and willbe moderated by Dean G. Assimos, MD.Total Caloric Intake Modulates Risk for Urinary Stones in Women: Results from The Women’s HealthInitiative (#2139): While obesity is loosely tied to the risk of kidney stones, researchers in this study fromthe University of California, San Francisco attempted to discover the exact causal relationship. They foundthat modifying total daily caloric intake may be an important measure in the reduction of stone disease.The researchers used data from the Women’s Health Initiative Observational Study and identified 78,551participants who were included based on data related to diet, body mass index (BMI) and occurrence ofsymptomatic stone disease. Even when adjusted for obesity, total caloric intake conferred an independentrisk of stone disease, suggesting that regulating the total number of calories ingested daily may play asignificant role in risk reduction for stone disease in obese and overweight people.Diet, Vegetarianism and Urolithiasis (#2146): Researchers from the Cancer Epidemiology Unit, Universityof Oxford, Oxford, UK, found that meat-heavy diets may be associated with an increased risk of developingkidney stones and that a high intake of fresh fruit, fiber and certain minerals may reduce risk. The teamstudied 50,617 participants in the Oxford arm of the International Agency for Research on Cancer’sEuropean Prospective Investigation into Cancer and Nutrition (EPIC) Project. 202 participants werediagnosed with kidney stones during the follow-up period. Regression analysis was used to examine theassociation of diet with risk after stratification by sex, method of recruitment and region of residence, andadjusting for smoking and drinking alcohol. Compared to those with a high meat diet, the incidence rate ofstones was .71 for moderate meat eaters, .52 for low meat eaters and .52 for fish eaters and vegetarians.Diets with high intake of fresh fruit, and those high in fiber, magnesium, iron and potassium, wereassociated with a reduction in stone disease. There was no association found with vegetable consumption,calcium or vitamin C.The Effect of Statin Medications On Urinary Stone Formation: A Ten Year Review of the Armed-ForcesHealth Longitudinal Technology Application (AHLTA) Database (#2233): Attempting to clarify the exactcause of kidney stone formation, a team of researchers from the University of California, San Franciscoinvestigated the relationship between hyperlipidemia (high cholesterol and triglycerides) and kidneystones, as well as the impact of statin medications (typically used to treat high cholesterol) on stone
  2. 2. formation. Patient records from the AHLTA database were used; 57,320, (36,341 male) were identifiedwith hyperlipidemia. 32,386 patients (20,063 male) were prescribed statin medications including 1,030(724 male) who developed a stone. While confirming the relationship of urinary stone disease withhyperlipidemia, the researchers found that the use of statin medications was associated with a reductionin risk of stone disease; the effect was seen more prominently in females.Do Antioxidants Lower The Risk Of Stone Disease? (#2239): Alpha-carotene, beta-carotene and beta-cryptoxanthin are known as antioxidants, nutrients found in legumes, nuts and grains that eliminate so-called free radicals, molecules that have been linked to certain diseases. In this study, authors from theUniversity of Iowa in Iowa City found that higher levels of these antioxidants in the body may beassociated with a lower risk of stone formation. Using data from adult participants in the National Healthand Nutrition Examination Survey (NHANES III) researchers compared serum levels of antioxidantsbetween those with and without a history of kidney stones, adjusting for covariates of age, gender, BMI,race/ethnicity, hypertension and metabolic syndrome. Of the 17,695 survey participants, 5.25 percentreported a history of kidney stones. After adjusting for covariates, mean levels of antioxidants weresignificantly lower in those with kidney stones: -9.36 percent for alpha carotene; -10.79 percent for beta-carotene and -8.48 percent for beta-cryptoxanthin. Lycopene and other antioxidant levels did notcorrelate with history of stones.Obesogenic Profile of Contemporary North American Renal Stone Patients (#1825): Body mass index(BMI) has limitations as a measure of obesity; and more importantly, as a method of accounting for fatdistribution throughout the body. Researchers from the McMaster Institute of Urology in Hamilton,Ontario, studied fat distribution and metabolic hormonal make up in stone patients and found that genderdifferences in fat distribution may account for failure of shockwave lithotripsy (SWL). This prospectivestudy included 113 patients (73 male, mean age of 54) undergoing treatment for renal stones betweenNovember 2009 and June 2010. Twenty-eight percent of patients had BMI within the normal range, while32 percent were overweight. Males had a higher proportion of visceral adiposity (fat located around theabdomen) while females had a higher peripheral adiposity (fat located in the arms and thighs). This findingmay impact the success of lithotripsy, as females have an increased skin-to-stone distance. In addition,levels of fat-related hormones adiponectin and leptin in stone patients may also tie risk of obesity-relatedmetabolic disorders to higher complication rates when treating stones.“There is robust evidence that diet has a significant impact on kidney stone formation. Consumption of abalanced, heart-healthy diet may reduce the risk of kidney stone formation,” said AUA spokesman Dean G.Assimos, MD. “The development of kidney stones is also associated with a number of systemic disorders,including obesity, hypertension, diabetes mellitus and coronary heart disease. Oxidative stress may playan underlying role in these associations.”NOTE TO REPORTERS: Experts are available to discuss this study outside normal briefing times. Toarrange an interview with an expert, please contact the AUA Communications Office at the numberabove or e-mail Communications@AUAnet.org.About the American Urological Association: Founded in 1902 and headquartered near Baltimore, Maryland, theAmerican Urological Association is the pre-eminent professional organization for urologists, with more than 17,000members throughout the world. An educational nonprofit organization, the AUA pursues its mission of fostering thehighest standards of urologic care by carrying out a wide variety of programs for members and their patients. ###
  3. 3. 2139TOTAL CALORIC INTAKE MODULATES RISK FOR URINARY STONES IN WOMEN: RESULTS FROM THEWOMEN’S HEALTH INITIATIVEThomas Chi, MD, Natalia Sadetsky, MD, PhD, Carmen Peralta, MD, MS, Arnold Kahn, PhD, Timothy Y.Tseng, MD, Matthew R. Cooperberg, MD, MPH, Marshall L. Stoller, MD, San Francisco, CAINTRODUCTION AND OBJECTIVES: The mechanism underlying the association between obesity and stonesremains poorly understood. Our objective was to examine the dietary factors that modulate risk for kidneystones in the obese and overweight.METHODS: Utilizing data from the Women’s Health Initiative Observational Study (a cohort of 93,676postmenopausal women aged 50-79 enrolled between 1994 and 1998 across 40 clinical sites in the UnitedStates), this prospective observational cohort study utilized self report and clinic visit assessment toidentify patients with at least one symptomatic episode of kidney stones. Clinic visit data was used tocalculate body mass index (BMI) for this cohort. Validated dietary questionnaires measured daily caloricand other diet-related intake. Patients were stratified into categories of BMI. Dietary intake was examinedfor risk factors modulating risk of stone disease in this population.RESULTS: For this analysis, 78,551 participants were included who had complete data on diet, BMI, andincidence of symptomatic nephrolithiasis. Within this group, 1,960 (2.5%) patients with a mean age of 63.7+ 7.6 years reported at least one episode of symptomatic stone occurrence. BMI demonstrated thestrongest association with increased risk of nephrolithiasis. Overweight (BMI 25.0-29.9) and obesity level I-III (BMI 30.0-34.9, 35.0-39.9, and > 40.0) individuals had unadjusted odds ratios of 1.3 (95% confidenceinterval 1.1-1.4), 1.8 (95% confidence interval 1.5-2.0), 2.1 (95% confidence interval 1.8-2.5), and 2.4 (95%confidence interval 1.9-2.9) respectively for an episode of symptomatic nephrolithiasis when compared tonormal individuals (BMI 18.5-24.9). With univariate analysis, ingesting a higher amount of total calories(>2500 kcal/day) conveyed an increased odds ratio for nephrolithiasis of 1.7 (95% confidence interval 1.4-2.0) when compared to a daily caloric intake of <1500 kcal/day. Adjusted for BMI, this odds ratio remainedelevated at 1.5 (95% confidence interval 1.2-1.8) for participants in the highest caloric intake group.CONCLUSIONS: Among various metabolic variables, obesity was most strongly associated with anincreased risk of stone disease, but when adjusted for these variables, total caloric intake conferred anindependent increased risk for nephrolithiasis. Regulating the total number of calories ingested daily mayplay a significant role in risk reduction for stone disease in obese and overweight individuals. To the bestof our knowledge, this is a newly identified dietary risk factor for nephrolithiasis.Source of Funding: none
  4. 4. 2146DIET, VEGETARIANISM AND UROLITHIASISBenjamin Turney, Naomi Allen, Paul Appleby, John Reynard, Jeremy Noble, Freddie Hamdy, Timothy Key,Oxford, United KingdomINTRODUCTION AND OBJECTIVES: Kidney stones are a major cause of urological morbidity. Up to 12percent of the population will have a kidney stone at some time and the incidence is rising internationally.Previous studies of diet and kidney stone prevalence have focused on specific nutrients but not onidentifiable dietary groups such as vegetarians. Our objective was to investigate the association betweendiet and urolithiasis risk in a population with a wide range of diets, including a high proportion ofvegetarians.METHODS: The association between baseline diet and kidney stone risk was examined among 50,617participants in the Oxford arm of the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford). 202 participants were diagnosed with kidney stones during the follow-up period using data fromHospital Episode Statistics in England and Scottish morbidity Records. Cox proportional hazards regressionwas used to examine the association of diet with risk after stratification by sex, method of recruitment andregion of residence and adjustment for smoking and alcohol.RESULTS: The risk of developing kidney stones was significantly associated with diet group; compared tohigh meat-eaters (>100g/day) , the incidence rate ratios for moderate meat-eaters (50-99g/day), lowmeat-eaters (<50g/day), fish eaters and vegetarians were 0.71 (95% CI 0.49-1.04), 0.52 (0.32-0.82), 0.52(0.31-0.88) and 0.53 (0.34-0.78), respectively (P=0.015 for heterogeneity). A high intake of fresh fruit wasassociated with a reduction in urolithiasis risk (P for trend =0.007), although there was no association withvegetable consumption. A high intake of fibre (P=0.003 for trend), magnesium (P=0.005), iron (P=0.007)and potassium (P=0.045) were also associated with a reduction in risk. Calcium and vitamin C intake werenot associated with the risk of stone disease.CONCLUSIONS: Diets that contain a high amount of meat may be associated with an increased risk ofdeveloping kidney stones. Conversely, a high intake of fresh fruit and fibre and certain minerals mayreduce the risk. This information may be important to help prevent the development of kidney stones.Source of Funding: none
  5. 5. 2233THE EFFECT OF STATIN MEDICATIONS ON URINARY STONE FORMATION: A TEN YEAR REVIEW OFARMED-FORCES HEALTH LONGITUDINAL TECHNOLOGY APPLICATION (AHLTA) DATABASEJames Masterson, Roger Sur, James LEsperance, Brian Auge, Marshall Stoller, San Diego, CAINTRODUCTION AND OBJECTIVES: The pathogenesis of urinary stone formation has not been elucidated.Traditional theories of abnormal urine chemistries do not fully explain urinary stone disease. Recently,vascular disease, hypertension, and obesity have been associated with stone formation. The purpose ofthis study was to investigate the relationship between hyperlipidemia and nephrolithiasis as well as theimpact of statin medications on stone formation.METHODS: The AHLTA patient medical records from the Southwestern United States region was queried(January 2000 - October 2010) to identify adult patients with hyperlipidemia. AHLTA database is anelectronic medical record for all active duty members, dependents and retirees. We then created twopredictor variables -- with and without anti-hyperlipidemic drugs--with the outcome variable as urinarystones. All subjects with a diagnosis of urolithiasis diagnosis were identified as well. Descriptive andunivariate analysis was performed.RESULTS: 57,320 patients (36,341 men) were identified with hyperlipidemia. 32,386 (20,064 men) patientswere prescribed statin medications including 1,030 of them (724 men, 306 women) who developed astone. Stones developed in 962 (617 men, 345 women) patients who were not taking a statin medication.6,313 patients were identified as having urolithiasis, including 3897(62.7%) men. 1,992(31.7%) of patientswith stones also had hyperlipidemia. The probability of a patient with hyperlipidemia having a diagnosis ofurolithiasis while on a statin medication was OR=0.819 (95% CI=0.749-0.895, p<0.0001) [OR=0.962 men(95% CI=0.863-1.074, p=.529) 0.599 women(95%CI=0.512-0.700, p<.001)]).CONCLUSIONS: We confirmed the relationship of urinary stone disease with hyperlipidemia. Moreoever,the use of statin medication, with the assumed reduction in hyperlipidemia, appears to reduce the risk ofstone disease, more pronounced for females.Source of Funding: None
  6. 6. 2239DO ANTIOXIDANTS LOWER THE RISK OF STONE DISEASE?Peter A. Holoch, Chad R. Tracy, Iowa City, IAINTRODUCTION AND OBJECTIVES: Recent data suggests that oxidative stress may be increased in stoneformers. Our objective was to evaluate the association between serum antioxidant levels and the self-reported prevalence of kidney stones.METHODS: Serum levels of antioxidants among adult participants in the National Health and NutritionExamination Survey (NHANES III) were compared between those with and without a history of kidneystones, adjusting for covariates of age, gender, BMI, race/ethnicity, diabetes, hypertension, and themetabolic syndrome.RESULTS: Of the 17,695 survey participants, 5.25% reported a history of kidney stones. Prevalence ofkidney stones was higher in males, white non-Hispanics, diabetics, and those with hypertension orincreased body mass index (BMI). After adjusting for covariates, mean levels of alpha-carotene, beta-carotene and beta-cryptoxanthin were significantly lower in those with kidney stones (-9.36%, -10.79%and -8.48%, respectively), while lycopene and other antioxidant levels did not correlate with history ofstone formation. Patients in the lowest quintile of alpha-carotene, beta-carotene and beta-cryptoxanthinlevels were 1.38, 1.33, and 1.66, respectively, more likely to form stones than those in the highest quintile.CONCLUSIONS: Higher levels of alpha-carotene, beta-carotene, and beta-cryptoxanthin may be associatedwith a lower risk of stone formation.Source of Funding: None
  7. 7. 1825OBESOGENIC PROFILE OF CONTEMPORARY NORTH AMERICAN RENAL STONE PATIENTSAnatoly Shuster, Christopher B Allard, Ayman Raees, Michael Patlas, Edward D Matsumoto, Jehonathan HPinthus, J Paul Whelan, Hamilton, CanadaINTRODUCTION AND OBJECTIVES: Obesity is linked to increased rates of renal stone (RS) formation andtreatment failures, and is usually defined according to body mass index (BMI). BMI has inherent limitationsas a measure of obesity and fails to account for fat distribution, a more accurate predictor of morbidity.Patterns of fat distribution may affect the success of extracorporeal shockwave lithotripsy (ESWL), sinceperipheral adipose tissue increases the skin-to-stone distance more than does visceral adipose tissue(VAT). The objective of this study was to characterize the fat distribution and metabolic hormonal milieu ina cohort of RS patients.METHODS: 113 patients (73 male; 40 female; mean age 54 years) undergoing treatment for RS betweenNovember 2009 and June 2010 at one center were prospectively enrolled; 81 met inclusion for BMIanalysis and 63 for %VAT. CT scans were analyzed for visceral and subcutaneous adipose tissue volumesfrom axial slices at 3 fixed levels (L2 vertebral body, umbilicus and anterior superior iliac spine) usingcommercial software (Clear Image Demo). Adipose tissue was defined as -250 to -30 Hounsfield Units. Theratio of visceral to total adipose tissue (%VAT) was calculated and BMI data collected. Adiponectin andleptin levels of fasting serum samples were measured by ELISA.RESULTS: 28% of patients had BMI within the normal range (<25kg/m2), while 32% were overweight(2535kg/m2). Mean BMI was 30kg/m2. 54% of females and 32% of males were obese or morbidly obese(BMI>30kg/m2). Mean %VAT was 47.7 and 29.7 for males and females respectively (p<0.001), indicatingrelatively higher visceral adiposity in males, and peripheral adiposity in females. Mean levels ofadiponectin and leptin were 7.67 and 17.50 respectively (normal values are 10ìg/ml and 10 ng/mlrespectively).CONCLUSIONS: In this cohort of RS patients, males had a higher proportion of visceral adiposity thanfemales (%VAT 47.7 vs. 29.7), while more females were obese or morbidly obese according to BMI. Thegender differences in fat distribution may affect ESWL success; obese females have more peripheraladiposity, increasing the skin-to-stone distance and, consequently, the probability of ESWL failure. Meanserum levels of adiponectin and leptin indicate that these RS patients are at risk of obesity-relatedmetabolic disorders and higher perioperative complication rates. These associations should be furtherinvestigated in a larger multi-center cohort.Source of Funding: none