Urolithiasis/Endourology

Stressful Life Events and Painful Recurrent Colic of Renal LithiasisDenise H. M. P. Diniz,* Nestor Schor and Sérgio Luis BlayFrom the Nephrology Division (DHMPD, NS) and Psychiatry Department (SLB), Universidade Federal de São Paulo (UNIFESP), Brazil

Purpose: There is strong evidence concerning the influence of life event stress on the onset and course of painful acuteepisodes in primary care. However, few studies have analyzed stressful life events in painful recurrent episodes of renal stonedisease. We evaluated the association between painful recurrent colic of renal lithiasis and stressful life events.Materials and Methods: We performed this case-control study in a primary care setting. Study participants were 194subjects (97 cases and 97 controls) matched according to age and gender. Cases were outpatients with a confirmed diagnosisof nephrolithiasis. The control group consisted of patients seen at the Ophthalmology Outpatient Clinic of the UniversityHospital, reporting only refraction symptoms and presenting no chronic or acute pathology. Main outcome measures reportedwere stressful life events as measured by the Social Readjustment Rating Scale.Results: The mean Social Readjustment Rating Scale of cases was significantly higher than controls at 257.56 (�193.81) vs144 (�131.24), respectively. Logistic regression revealed that belonging to the case group increased the chances of showingpositive results on the scale greater than or equal to 100 (OR 3.02, 95% CI 1.64-5.59) and the chance of presenting results of200 or greater was 2.87 (OR 2.87, 95% CI 1.58-5.22).Conclusions: Stressful life events were significantly greater among cases than controls.

Key Words: kidney calculi, life change events, lithiasis, colic, stress

In the last 4 decades various researchers have focused onevaluating the association between stressful life eventsand the development of illness.1–10 Many of these stud-

ies have brought out strong evidence4–6 linking stress withrecurrent painful diseases such as headache,4 musculoskel-etal pain,9 coronary artery disease,5,8,10 and abdominalpain,6 albeit in studies using differing designs in diversepopulations.4,6,10

However, a search of the literature for specific studiesassociating stress and recurrent painful renal colic resultedin only 1 article involving the systematic administration of aquestionnaire based on standardized diagnostic instrumentspreviously used in primary care.11 In light of the dearth ofinformation in the area, this study was designed to testwhether the frequency of stressful life events before theonset of renal colic crises is greater in patients with thispathology than in a group of control subjects.

METHODS

To evaluate stressful life events in patients with recurrentrenal colic a case-control design was applied. A total of 194subjects (97 cases/97 controls) was seen at Hospital SãoPaulo-UNIFESP clinic. Cases were selected from all pa-tients followed at the renal lithiasis clinic from 2001 and2004. All charts were examined to check inclusion criteria.

Submitted for publication December 12, 2005.Nothing to disclose.Study received approval from the Ethics Committee of Univer-

sidade Federal de São Paulo, Brazil (0843-03).* Correspondence: Nephrology Division, Universidade Federal de

São Paulo, Escola Paulista de Medicina, São Paulo, SP Rua Botu-

catu, 740 - 04023-900, São Paulo-SP-Brazil (telephone: 55-11 5574-6300; FAX: 55-11 5573-9652; e-mail: denise_diniz@uol.com.br).

0022-5347/06/1766-2483/0THE JOURNAL OF UROLOGY®

Copyright © 2006 by AMERICAN UROLOGICAL ASSOCIATION

2483

Patients were selected at random, but were included in thestudy after verifying all inclusion and exclusion criteria inan initial interview.

Cases were outpatients with a confirmed diagnosis ofrenal lithiasis under treatment by nephrologists at the Ne-phrology Outpatient clinic of this university hospitalthrough case histories, clinical symptoms, image examina-tion and blood/urine laboratory routines. Although patientshad a confirmed diagnosis using images and subsidiary ex-aminations, the number of episodes of recurrent renal colicsince diagnosis was taken from patient subjective descrip-tion, and new laboratory examinations were not performedto check each reported episode. Patients had a history of atleast 2 episodes in a 3-year period but were currently in aninter-crisis interval. The renal stone diagnosis was donebefore study evaluations. Assessment was performed afterat least 2 months following the last renal colic episode toavoid disruption of quality of life during this acute crisis,potentially influencing results. Exclusion criteria were preg-nancy, mental disorders (psychosis, mental deficiency, alco-hol or drug abuse) or painful crises not related to renalstones, or receiving drug therapy for anxiety, depressionand/or any other psychiatric treatment. There were 7 pa-tients initially selected as cases who refused to participate.The reasons for refusal were inability to wait for the inter-view or to be present for another interview. Patient recordsshowed no statistically significant difference between par-ticipants and nonparticipants or influence on results.

Editor’s Note: This article is the fifth of 5 published inthis issue for which category 1 CME credits can beearned. Instructions for obtaining credits are given

with the questions on pages 2752 and 2753.

Vol. 176, 2483-2487, December 2006Printed in U.S.A.

DOI:10.1016/j.juro.2006.07.156

STRESSFUL LIFE EVENTS AND RECURRENT RENAL COLIC2484

The control group consisted of 97 patients from the Oph-thalmology Outpatient Clinic of this university hospital withrefraction symptoms and no associated disease. Controlswere individually matched for gender and age, and wereselected consecutively. The exclusion criteria were the sameas those previously mentioned, in addition excluding anyonewith renal disease. Only 5 of the controls initially selectedwere unable to participate in the study. Demographic infor-mation (such as race, gender and age) showed no statisti-cally significant difference between participants and non-participants or influence on results.

ProceedingsThe study was approved by the Ethics Committee of Uni-versidade Federal de São Paulo, Brazil (0843-03). After ob-taining written consent to participate in the study, cases andcontrols filled out a questionnaire to collect sociodemo-graphic data. The clinical treatment of patients who refusedto participate was not influenced. Interviewing was doneface-to-face with trained and professional interviewers notinvolved in clinic routine. The questionnaire consisted ofdemographic information, present and past history of kidneystone disease, time of diagnosis, time of initial painful symp-toms of renal stone formation, number of episodes of renalcolic, and socioeconomic information through the Escala daAssociação Brasileira dos Institutos de Pesquisas de Mer-cado (ABIPEME). A questionnaire was applied to assess lifeevents along with the other evaluation forms. The controlgroup followed the same sequence as cases. The question-naires and database were checked to evaluate data consis-tency.

InstrumentsStressful life events were evaluated by the Social Read-justment Rating Scale, developed in 1967 by Holmes andRahe,1 and translated and adapted for Brazil in 1984 byLipp.12 The Social Readjustment Rating Scale is a widelyused instrument in fieldwork to measure stressful lifeevents,13 and proposes that the effort required for anindividual to readjust to society following stressful lifeevents causes exhaustion that can precipitate the onset ofmany different diseases.

This scale takes only the great events of a person’s lifeinto account rather than everyday events. Researchersorganized a list of significant events such as divorce,death in the family, birth of a child in the family, jobchange, etc. The list is presented to individuals beingexamined, asking them if they have been exposed to any ofthese events during the year before the event being stud-ied.

Event scores are weighted by an anticipated impact foreach event. Impact expectations were normalized for theAmerican population. While the questionnaire has beentranslated and validated in our environment, results havenot been published. Total scores are divided into 4 impactcategories of less than 119 —low, 119 to 199 —moderate,200 to 299 —median, and more than 300 — high. The in-strument is simple to use and has face validity (see Ap-pendix), and is used as an indicator of major events whiledisregarding smaller problems. According to medianscores obtained in the 2 groups, cutoff points were adopted

for defining a positive SRRS stressful events of 100 or

greater (low to high impact) and 200 or greater (median tohigh impact).

Statistical AnalysisSample size was calculated according to a preliminarystudy evaluating symptoms of anxiety and depression inrenal lithiasis in subjects with a history of recurrent renalcolic. Our findings indicate a 12.5% difference betweencases and controls with low levels of anxiety. Thus, weneeded at least 92 subjects per group (92 cases and 92controls) to detect such a difference at a 5% level of sig-nificance with discrimination power higher than 90%.

The categorical variable was presented in absolute andrelative frequencies (%), and interval variables by mean,standard deviation, median, maximum and minimum val-ues. The chi-square test was used to analyze the fre-quency of each of the items in the Social ReadjustmentRating Scale for comparison among groups. Factors iden-tified as possibly associated with stressful life events afterbivariate analysis entered into multiple logistics regres-sion to identify the independent effects on stressful im-pact (100 or greater low to high impact and 200 or greatermedian to high impact). A p �0.05 was considered signif-icant.

RESULTS

Table 1 shows sample sociodemographic data. Of the 194patients studied 126 were female (63%), mean age 44 � 11years old (range 18 to 65), a majority were white race(70%), and 51.5% of cases and 48.5% of controls weresocioeconomic status C (middle class). Table 2 shows sta-tistically significant differences between cases and con-trols in relation to total scores on the Social ReadjustmentRating Scale, and in relation to the distribution of the 4scale categories. Table 3 shows statistically significantassociations between the impact of events, and cutoffpoints of 100 or greater and 200 or greater between casesand controls.

Logistic regression revealed that belonging to the casesgroup increased the likelihood of presenting with scores of100 or greater on the SRRS (OR 3.02, 95% CI 1.64-5.59)and it increased the chance of presenting with scores of200 or greater on the SRRS (OR 2.87, CI 1.58-5.22). Table4 compares groups for the proportion represented by eachof the components on the events scale.

DISCUSSION

In addition to demonstrating an association betweenstressful life events and kidney stones, overall findings forthe year before renal colic episode onset indicate an in-creased level of stressful life events for our cases, in thatmore than a third of the sample revealed high (300 orgreater) stress scores. On item analysis there was greaterimpact of some life events for cases than for controls,especially regarding changes in professional activity suchas changes in line of work and schedule, as well as finan-cial, relational, social and physical difficulties.

Pain is an experience determined by a confluence ofprecipitating and triggering causal factors, while simul-taneously presenting various dimensions such as senso-

rial, affective, cognitive, etc. Thus, pain is a multidimen-

STRESSFUL LIFE EVENTS AND RECURRENT RENAL COLIC 2485

sional experience produced by characteristic patterns ofnerve impulses generated in a widely distributed neuralnetwork in the brain known as the neuromatrix which isaffected by stress.14 According to Figueiró stress is asubjective experience where events may or may not beperceived as stressors, and painful processes have a rec-ognized role in disrupting organism homeostasis.15 In ad-dition, according to Selye stress is a process and not asingle reaction, in that at the moment in which a person issubject to a source of tension, a biochemical process isestablished making acute and chronic hormonal modifica-tions possible, which may include imbalances that stimu-

TABLE 1. Baseline characteristics of cases and controls

Cases Controls

No. sex (%):Male 34 (35.1) 34 (35.1)Female 63 (64.9) 63 (64.9)

No. age group (%):18–19 1 (1.0) 1 (1.0)20–29 9 (9.3) 8 (8.2)30–39 24 (24.7) 23 (23.7)40–49 33 (34.0) 35 (36.1)50–59 22 (22.7) 21 (21.6)60–65 8 (8.2) 9 (9.3)

No. marital status (%):Married 72 (74.2) 46 (47.4)Unmarried 25 (25.7) 51 (52.6)

Yrs education:Mean � SD 6.7 � 3.9 7.4 � 4.1Range 0–17 0–17

No. student level (%):4 Yrs or less 24 (24.7) 17 (17.5)4 Yrs or greater 73 (75.2) 80 (82.4)

No. religion (%):No religion 2 (2.0) 7 (7.2)Catholic 68 (70.1) 54 (55.7)Evangelist 18 (18.6) 29 (29.9)Other 9 (9.0) 8 (8.0)

No. race (%):White 71 (71.0) 68 (68.0)Nonwhite 28 (28.0) 32 (32.0)

Time of diagnosis:Mean � SD 12.2 � 11.0 10.8 � 11.1Median 7 8Range 0.5–39 0–49

No. crises:Mean � SD 20.9 � 25.9 0Median 10 0Range 2–120 0

No. socioeconomic status(ABIPEME) (%):A 2 (2.1)B 20 (20.6) 21 (21.6)C 50 (51.5) 48 (48.5)D 21 (21.6) 25 (25.8)E 4 (4.1) 4 (4.1)

TABLE 2. Mean scores and frequency distribution of the SocialReadjustment Rating Scale

Cases Controls

Social readjustment rating:Median � SD 257.56 � 193.81 144.54 � 13.24Median 209 100Range 0–802 0–595

Student’s t test �0.001No. social readjustment rating (%):

Less than 119 (low) 28 (28.9) 53 (54.6)119–199 (moderate) 16 (16.5) 15 (15.5)200–299 (median) 18 (18.6) 18 (18.6)300 or Greater (high) 35 (36.1) 11 (11.3)

Chi-square test �0.001

late the development of lithiasis.16 Among other possibil-ities the association between time of disease and a greaternumber of recurrent renal colic episodes can be inter-preted as reflecting increased exposure to stressful lifeevents. In those who are more vulnerable this increasedexposure can bring on homeostatic imbalances such asthose connected with lithogenic and litholytic factors.

Our findings are in line with those of a study done inthe United States with a similar methodology that pro-posed an explanation for idiopathic hypercalciuria andnephrolithiasis involving stressful events in simulta-neously reducing litholytic urinary constituents (magne-sium, citrate), promoting hyperoxaluria and decreasingurinary volume.11 Najem et al also commented that theoverall prevalence of stressful life events was significantlygreater among cases than controls.11

Compared with other pathological conditions charac-terized by painful episodes, our findings reflect a similartendency in association between stressful life events andrecurrent painful crises such as chronic headache.4 Otherstudies have shown the role of life events in other pathol-ogies such as cancer and cardiovascular disease.5,10,17,18

Like most studies done in primary health care services,this research had some limitations. The patients studiedare predominantly female while nephrolithiasis is morecommon in men according to the literature. A recent studyin the Renal Lithiasis Clinic of this university (wherecases were selected) revealed that of the 1,074 patientsactively being followed in clinical treatment 604 (56.2%)are women and 470 are men (43.8%). Thus, more womenwere selected because selection took place in sequentialorder and all patients treated in the clinic in the last 3years had the same chance to be included in the sample.In addition, it has been proposed that the higher preva-lence of women in studies relying on self-reporting couldbe due to differences in reporting behavior, ie women aremore likely to report medical complaints than men.19,20

Another observation concerns the long course of the dis-ease. However, we should note that our study focused onpatients in an inter-crisis period and emphasize the im-portance of sample selection procedures as an essentialpart of the study. Our case subjects were selected ran-domly to insure greater validity of results and a represen-tative sample of patients in this environment. A finalpoint concerns the validity question for the instrumentused to evaluate life events. Although this questionnairehas been validated in Brazil the study results have notbeen published. However, given the questionnaire’s facevalidity and the ease of administration, the scale was used

TABLE 3. Association between results of events scale andinterviewed group

Controls Cases

No. events scale (%):Less than 100 47 (48.5) 23 (23.7)100 or Greater 50 (51.5) 74 (76.3)

p Value �0.001No. events scale (%):

Less than 200 70 (72.2) 46 (47.4)200 or Greater 27 (27.8) 51 (52.6)

p Value �0.001

to evaluate large variations in psychosocial impact.

STRESSFUL LIFE EVENTS AND RECURRENT RENAL COLIC2486

CONCLUSIONS

Our findings highlight an association between stressfullife events and painful recurrent renal lithiasis. Furtherstudies are called for to clarify the pathophysiologicalmechanisms connecting life events and the onset of pain-

TABLE 4. Social Readjustment Rating Scale

Stressful Life Events No. Cases (%) No. Controls (%) p Value

Death of spouse 3 (3.1) 1 (1.0) 0.621Divorce 5 (5.2) 0 (0.0) 0.059Marital separation 13 (13.4) 6 (6.2) 0.091Prison 3 (3.1) 0 (0.0) 0.246Death in family 43 (44.3) 29 (29.9) 0.037*Accident or disease 33 (34.0) 15 (15.5) 0.003*Marriage 17 (17.5) 5 (5.2) 0.007*Loss of job 14 (14.4) 12 (12.4) 0.673Reconciliation withspouse

5 (5.2) 6 (6.2) 0.756

Retirement 2 (2.1) 3 (3.1) 1.000Disease in family 43 (44.3) 25 (25.8) 0.007*Pregnancy 16 (16.5) 10 (10.3) 0.206Sexual difficulties 20 (20.6) 9 (9.3) 0.027*Birth of child in family 30 (30.9) 29 (29.9) 0.876Job change 25 (25.8) 17 (17.5) 0.163Change in financialcondition

44 (45.4) 25 (25.8) 0.004*

Death of close friend 20 (20.6) 14 (14.4) 0.257Change in line of work 24 (24.7) 9 (9.3) 0.004*Change in frequency ofarguments withspouse

18 (18.6) 5 (5.2) 0.004*

Purchase of expensivehouse

4 (4.1) 6 (6.2) 0.516

Finished paying offloan

6 (6.2) 9 (9.3) 0.420

Change in jobresponsibilities

28 (28.9) 6 (6.2) �0.001*

Son/daughter leaveshome

4 (4.1) 2 (2.1) 0.683

Problems with police 0 (0.0) 1 (1.0) 1.000Recognition foroutstandingprofessional work

8 (8.2) 3 (3.1) 0.121

Spouse began orstopped working

16 (16.5) 4 (4.1) 0.005*

Began or stoppedstudying

18 (18.6) 12 (12.4) 0.233

Increase or decrease inpeople living inhousehold

27 (27.8) 16 (16.5) 0.057

Change in personalhabits

18 (18.6) 8 (8.2) 0.035*

Problems with boss 9 (9.3) 2 (2.1) 0.030*Change in workschedule

17 (17.5) 4 (4.1) 0.003*

Move to another house 27 (27.8) 15 (15.5) 0.036*Change of school 7 (7.2) 5 (5.2) 0.551Change of recreationalactivities

16 (16.5) 2 (2.1) 0.001*

Change of religiousactivities

12 (12.4) 5 (5.2) 0.076

Change of socialactivities

14 (14.4) 4 (4.1) 0.013*

Purchase on credit ofmoderate value

16 (16.5) 6 (6.2) 0.024*

Change in sleepinghabits

22 (22.7) 4 (4.1) �0.001*

Change in frequency offamily gatherings

16 (16.5) 4 (4.1) 0.005*

Change in eatinghabits

21 (21.6) 12 (12.4) 0.085

Vacation 36 (37.1) 41 (42.3) 0.463Christmas (meeting,gathering)

52 (53.6) 57 (58.8) 0.469

Fined for smallinfractions

8 (8.2) 2 (2.1) 0.100

Other problems 15 (15.5) 6 (6.2) 0.038*

ful recurrent renal colic episodes.

APPENDIX

Social Readjustment Rating Scale (Holmes andRahe, 1967; translation by Lipp, 1984)

Indicate events that occurred in the past year:

1. Death of spouse 1002. Divorce 733. Marital separation 654. Prison 635. Death in the family 636. Accident or illness 537. Marriage 508. Loss of job 479. Reconciliation with spouse 4510. Retirement 4511. Illness in the family 4312. Pregnancy 4013. Sexual difficulties 3914. Birth in the family 3915. Change of work 3916. Change in financial condition 3817. Death of close friend 3718. Change in line of work 3619. Change in frequency of arguments with spouse 3520. Purchase of house of high value 3121. Finished paying off loan 3022. Change of work responsibility 2923. Son/daughter leaves home 2924. Difficulties with police 2925. Recognition for outstanding professional work 2826. Spouse began or stopped working 2627. Began or stopped studying 2628. Addition or reduction in people living in the house 2529. Change of personal habits 2430. Difficulty with boss 2331. Change of work schedule 2032. Change of house 2033. Change of school 1934. Change of recreational activities 1935. Changes of religious activities 1836. Changes of social activities 1737. Purchase on credit of middle value 1638. Change in sleeping habits 1539. Change in the frequency of family gatherings 1540. Change in eating habits 1341. Vacation 1242. Christmas 1243. Fined for small infractions 11

ScoreProbability of having

health problems

Moderate (150 to 119) 37%Median (200 to 299) 51%High (over 300) 79%

Abbreviations and Acronyms

SRRS � Social Readjustment Rating Scale

REFERENCES

1. Holmes, T. H. and Rahe, R. H.: The Social Readjustment Rat-ing Scale. J Psychosom Res, 11: 213, 1967

2. Bebbington, P., Tennant, C., Sturt, E. and Hurry, J.: Thedomain of life events: a comparison of two techniques ofdescription. Psychol Med, 14: 219, 1984

3. Brown, G. W., Bifulco, A., Harris, T. and Bridge, L.: Life stress,chronic subclinical symptoms and vulnerability to clinicaldepression. J Affect Disord, 11: 1, 1986

4. De Benedittis, G. and Lorenzetti, A.: The role of stressful lifeevents in the persistence of primary headache: major eventsvs. daily hassles. Pain, 51: 35, 1992

5. Billing, E., Hjemdahl, P. and Rehnqvist, N.: Psychosocial vari-ables in female vs male patients with stable angina pectoris

and matched healthy controls. Eur Heart J, 18: 911, 1997

STRESSFUL LIFE EVENTS AND RECURRENT RENAL COLIC 2487

6. Boey, C. C. and Goh, K. L.: Stressful life events and recurrentabdominal pain in children in a rural district in Malaysia.Eur J Gastroenterol Hepatol, 13: 401, 2001

7. Maddock, C. and Pariante, C. M.: How does stress affect you?An overview of stress, immunity, depression and disease.Epidemiol Psichiatr Soc, 10: 153, 2001

8. Menendez Villalva, C., Montes Martinez, A., Nunez Losada, C.,Fernandez Dominguez, M. J., Gamarra Mondelo, T. andBujan Garmendia, S.: Environmental stress and cardiovas-cular reactivity: the effect of stressful life events on hyper-tense patients. Aten Primaria, 30: 631, 2002

9. Knardahl, S.: Psychological and social factors at work: contri-bution to musculoskeletal disorders and disabilities. G ItalMed Lav Ergon, 27: 65, 2005

10. Rafanelli, C., Pancaldi, L. G., Ferranti, G., Roncuzzi, R.,Tomba, E., Milaneschi, Y. et al: Stressful life events anddepressive disorders as risk factors for acute coronary dis-ease. Ital Heart J Suppl, 6: 105, 2005

11. Najem, G. R., Seebode, J. J., Samady, A. J., Feuerman, M. andFriedman, L.: Stressful life events and risk of symptomatickidney stones. Int J Epidemiol, 26: 1017, 1997

12. Lipp, M. E. N.: Stress e suas implicações. Estud Psicol, 1: 5, 198413. Savoia, M. G.: Instrumentos para avaliação de eventos vitais e

estratégias de enfrentamento (coping) em situações de es-tresse. In: Escalas de Avaliação Clínica em Psiquitria ePsicofarmacologia. Edited by C. Gorenstein, L. H. S. G.Andrade and A. W. Zuardi. São Paulo: Lemos Editorial, pp.377–386, 2000

14. Melzack, R.: Pain and stress: a new perspective. In: Psychos-ocial Factors in Pain: Critical Perspectives. Edited by R. J.Gatchel and D. C. Turk. New York: The Guilford Press, pp.89-106, 1999

15. Figueiró, J. A. B.: Dor e stress. In: Mecanismos Neuropsicofi-siológicos do Stress: Teoria e Aplicações Clínicas. Edited byM. E. N. Lipp. São Paulo: Casa do Psicólogo, pp. 149–154,2003

16. Selye, H.: History and present status of the stress concept. In:Handbook of Stress: Theoretical and Clinical Aspects. Ed-ited by L. Goldberg and S. Breznitz. New York: The FreePress, 1984

17. Santos, A. M., Nobre, E. L., Garcia e Costa, J., Nogueira, P. J.,Macedo, A., De Castro, J. J. et al: Grave’s disease andstress. Acta Med Port, 15: 423, 2002

18. Fenga, C., Micali, E., Cacciola, A., Trimarchi, G. and Germano,D.: Stressful life events and fibrinogen level in middle-agedteachers. Psychopathology, 37: 64, 2004

19. Andrade, L., Walters, E. E., Gentil, V. and Laurenti, R.: Prev-

alence of ICD-10 mental disorders in a catchment area in

the city of Sao Paulo, Brazil. Soc Psychiatry PsychiatrEpidemiol, 37: 316, 2002

20. Bingefors, K. and Isacson, D.: Epidemiology, co-morbidity, andimpact on health-related quality of life of self-reportedheadache and musculoskeletal pain—a gender perspective.Eur J Pain, 8: 435, 2004

EDITORIAL COMMENT

This is a study of 97 patients with a history of renal colic and97 control patients undergoing refractive studies at an oph-thalmology clinic, comparing the frequency of stressful lifeevents in both groups. The time frame used for the patientswith renal colic is the year preceding the most recent episodeof colic. Although the possibility of a link between stress andstone formation is questioned relatively frequently by stoneformers, published support for such an association is scarce.Since it is well known that stone passage and colic may notoccur at the time of stone formation, the potential implica-tions of this report are that stress may be associated with anincreased risk of stone formation and/or or passage of pre-existing stones.

There is limited information suggesting that stress maypromote stone formation. A study of 200 stone formers and200 matched controls (reference 11 in article) showed anincreased frequency of stressful incidents in stone formers inthe 2 years preceding stone treatment, although the ques-tionnaire used was not validated. An increase in urinaryexcretion of calcium, oxalate and uric acid has been demon-strated in response to stress.1-3 This article provides addi-tional support for the possibility that stress may be involvedin stone formation in some patients.

Denis H. HoskingSection of Urology

Health Sciences Centre and the University of ManitobaWinnipeg, Manitoba, Canada

1. Brundig, P., Berg, W. and Schneider, H. J.: Stress and risk ofurolith formation. I. The influence of stress on lithogenousurinary substances (author’s transl). Urol Int, 36: 199, 1981

2. Schmucki, O., Asper, R. and Zortea, C.: Stress and urolithiasis.Urol Int, 39: 159, 1984

3. Walters, D. C.: Stress as a principle cause of calcium oxalate

urolithiasis. Int Urol Nephrol, 18: 271, 1986