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Saudi Journal of Kidney Diseases and Transplantation
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Year : 2012  |  Volume : 23  |  Issue : 6  |  Page : 1232-1237
A retrospective study of the seasonal pattern of urolithiasis

1 Department of Urology, Gulf Medical College Hospital and Research Center, Ajman, United Arab Emirates
2 Research Division, Gulf Medical University, Ajman, United Arab Emirates
3 Department of Surgery, Gulf Medical University, Ajman, United Arab Emirates
4 Department of Biochemistry, Gulf Medical University, Ajman, United Arab Emirates
5 Department of Community Medicine, Gulf Medical University, Ajman, United Arab Emirates
6 Research Laboratory, Gulf Medical University, Ajman, United Arab Emirates

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Date of Web Publication17-Nov-2012


This retrospective descriptive study was conducted among patients who presented with variable symptoms of urolithiasis at the Department of Surgery and Urology of Gulf Medical College Hospital and Research Centre (GMCHRC), Ajman, United Arab Emirates (UAE), in order to assess whether the occurrence of urolithiasis differed in relation to season, temperature and humidity. A checklist was used for abstracting the case record and analysis was performed using PASW 17 version. Maximum number of cases was below the age of 40 years, with a male to female ratio of 5.2:1. The present study revealed a higher number of cases during summer compared with the other seasons, but it was not statistically significant. No significant correlation was seen between atmospheric temperature, relative humidity and number of cases with urolithiasis. Our study also revealed that the admission rate for renal colic was higher in the summer season as against the rest of the year, although the difference was not significant. In conclusion, urolithiasis is an important public health issue that predominantly affects people of the productive age groups. Men are affected more commonly than women. No significant seasonal variation in the number of patients with urolithiasis was observed in the study.

How to cite this article:
Freeg MH, Sreedharan J, Muttappallymyalil J, Venkatramana M, Shaafie IA, Mathew E, Sameer R. A retrospective study of the seasonal pattern of urolithiasis. Saudi J Kidney Dis Transpl 2012;23:1232-7

How to cite this URL:
Freeg MH, Sreedharan J, Muttappallymyalil J, Venkatramana M, Shaafie IA, Mathew E, Sameer R. A retrospective study of the seasonal pattern of urolithiasis. Saudi J Kidney Dis Transpl [serial online] 2012 [cited 2022 Aug 17];23:1232-7. Available from: https://www.sjkdt.org/text.asp?2012/23/6/1232/103565

   Introduction Top

Urolithiasis is the presence of stones in the urinary system, and remains a common public health issue as well as a preventable cause of morbidity. The estimated global prevalence of urolithiasis in developed countries is between 5% and 13%, and, in developing countries, it is 0.5-1%. [1],[2],[3],[4] The overall probability of forming stones differs in various parts of the world: 1-5% in Asia, 5-9% in Europe, 13% in North America and 20% in Saudi Arabia. [2],[3],[4] Sub-tropical and tropical climate and better socio-economic standards of living may predispose to the increased occurrence of urinary stone disease.

An association between temperature and seasonal pattern of urinary stone disease has been observed. Temperature far above the comfort zone increases perspiration and results in concentrated urine. This, in turn, will promote increased urinary crystallization. [5] Studies conducted in regions with extreme temperature showed the incidence rising in the summer months and falling in the winter months. [6],[7] In addition to regional variation in stone disease, evidence is mounting that in Western societies the overall prevalence of stone disease is increasing. [8],[9]

The incidence of stone disease is expected to increase in individuals with persistently low urinary volumes, especially in warmer seasons. [10] High perspiration and high concentration of stone-forming substances in the urine during summer months lead to the highest incidence of urolithiasis. [11] Some authors suggest that increased exposure to sunlight causes increased production of 1,25-dihydroxyvitamin D 3 and increased urinary calcium excretion, [12] which may lead to increased number of urinary stone cases during the summer months. [13] Some investigators found that the frequency of kidney colic was higher in summer than in winter months, which might be due to a relative vitamin D hyper-vitaminosis, a greater intake of oxalate or a relative dehydration. [14] Although the reduced intake of water and consequent reduction of urinary volume are likely during fasting in Ramadan, the effect of fasting on urinary stone formation is controversial. [15] Transient variations in stone prevalence, such as seen with desert military deployments [16],[17],[18] and seasonal cyclicity, [19],[20],[21],[22],[23] can also be accounted for by temperature changes. It is also demonstrated that both urinary calcium excretion and renal stone episodes are increased during the warmer weather. [24]

The seasonal variations in urolithiasis have not been studied in Ajman. This study was conducted in Ajman, UAE, to assess whether the occurrence of urolithiasis differed with regard to season, temperature and humidity.

   Materials and Methods Top

This retrospective, descriptive study was conducted on patients who presented with variable symptoms of urolithiasis at the Department of Surgery and Urology of Gulf Medical College Hospital and Research Centre (GMCHRC), Ajman, United Arab Emirates (UAE). The UAE has a warm climate with short spring, winter and autumn seasons. Urinary output and biochemical parameters were noted on all study patients. Records of urolithiasis cases confirmed by ultrasonography during 2007-2009 were retrieved from the Department of Medical Records and a checklist was used for abstracting the data from case records after obtaining approval of the ethics committee. The patients' age, gender and religion and the seasonality of disease were assessed. The total number of patients who visited the hospital and the number of urolithiasis cases were recorded for each month. The year was divided into four seasons: December to March as winter; April and May as spring; June to September as summer and October and November as autumn. Atmospheric temperature measurements of Ajman Emirate were also obtained from the Ajman Statistical Department.

The data were analyzed using PASW 17 version. We calculated frequencies and percentage proportion for socio-demographic characteristics. The values are given as mean ± SD and percentage of measurement. Spearman's correlation coefficient was used to determine whether there was any correlation between number of urolithiasis cases and temperature in the different months.

   Results Top

[Table 1] shows the socio-demographic characteristics of patients with urolithiasis in the present study. Of the 458 patient records analyzed, 23.4% were seen in 2007, 30.3% in 2008 and 46.3% in 2009, showing a gradual increase. The age of the patients ranged between 4 and 65 years. The mean age was 33.1 ± 8.6 years. Majority (84.1%) of the patients were under 40 years of age. Among the total patients, 384 (83.8%) were males and 74 (16.2%) were females, with a male to female ratio of 5.2:1. Among males, 84.1% and among females 83.8% were less than 40 years of age. With regard to religion of the patients with urolithiasis, 70.7% were Muslims, 22.5% were Hindus and the remaining were Christians. Among the patients with urolithiasis, 76.2% were non-Arab and 23.8% were from Arab countries. Majority of the study participants were expatriates doing outdoor jobs. Sixty-two percent of the stone formers presented for the first time.
Table 1: Socio-demographic characteristics of the study patients.

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The mean temperature in the different months and number of urolithiasis cases corresponding to each month are plotted in a scatter diagram in [Figure 1]. Spearman correlation coefficient did not show a significant correlation between atmospheric temperature and number of urolithiasis cases.
Figure 1: Scatter diagram showing mean temperature and number of cases of urolithiasis.

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Month-wise mean relative humidity and number of urolithiasis cases are depicted in [Figure 2]. Spearman's rank correlation coefficient between relative humidity and number of urolithiasis cases was found to be -0.2, which was not statistically significant.
Figure 2: Mean relative humidity and number of urolithiasis cases.

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The relative frequency of urolithiasis cases, with regard to total number of cases reporting to the hospital during 2007-2009, is given in [Table 2]. In the year 2007, the relative frequency of urolithiasis cases observed was 60/100,000 patients reporting to the hospital. Maximum number of cases was observed in the months of September and October (107/100,000 and 110/100,000 respectively). In the year 2008, the relative frequency of urolithiasis cases observed was 68 per 100,000 patients reporting to the hospital. Maximum number of cases was observed during the months of January and February (127/100,000 and 103/100,000, respectively). In the year 2009, the relative frequency of urolithiasis cases observed was 95/100,000 patients reporting to the hospital. Maximum number of cases was observed during June and July (269/100,000 and 173/100,000, respectively). Although the dietary habits were studied, the daily salt consumption was not assessed separately. However, none of the records showed increased salt consumption in any season. Excess water consumption was reported in the summer months compared with the other seasons.
Table 2: Month-wise relative frequency of urolithiasis cases.

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   Discussion Top

Information on the seasonal pattern of urolithiasis among stone formers is important for the treating physician to apply both pharmacological and non-pharmacological interventions. Urolithiasis was more frequent in men than in women in our study, with a male to female ratio of 5:1. This observation is in accordance with studies conducted by Naas, [14] Fetter et al, [15] Almby et al [25] and Juuit et al, [26] which show that urolithiasis is predominantly seen among males compared with females. The male-to-female ratio ranges from 1.2:1 in Iran [21] and 1.6:1 in Thailand [22] to 2.5:1 in Iraq [23] and 5:1 in Saudi Arabia. [27]

In our study, the maximum number of cases was below 40 years of age. This finding is in agreement with the observations made by Kassimi et al, [16] Hanash et al, [17] Abomelha et al [18] and Naas et al. [14] They observed that urolithiasis occurred more regularly in the third decade of life.

In our study, we found more number of cases during summer compared with the other seasons, but the difference was not statistically significant. Chauhan et al [28] conducted a retrospective study in New Jersey and observed that renal colic visits were more common during the warmer months, and that it was highest in older patients and male gender. Chen et al, [29] in their study conducted in Taiwan, observed that urinary calculi-related colic attacks were highest from July to September, and a decline was seen in the winter months. Stone disease in the United States shows marked geographic variability; it has been found in several studies that the Southeast has a 50% higher prevalence of stone disease than the Northwest. [9],[30],[31] Davidson et al in their study observed that the season with highest number of stone presentations was during autumn and the lowest was in spring, even though the observation was not statistically significant. They also reported that the season of presentation did not differ significantly by age, gender, stone size, location or whether patients presented with pain, hematuria or incidental. [32] A study by Al-Hadramy observed that during the summer season, the urine volume and pH decrease and, thus, supersaturation of calcium oxalate and uric acid occurs. [12]

A retrospective study conducted by Pincus et al [33] observed that the rate of urolithiasis was significantly greater in summer when compared with winter. Baker et al [34] demonstrated significant seasonal variation in urinary stone incidence. A study by Chen et al reported that during the summer and autumn seasons, the diagnosis of renal stone was more compared with the other seasons. [29]

In our study, there was no relation between number of stone formers and the fasting month of Ramadan, and this observation is consistent with the study conducted by Al-Hadramy. [12] Basiri et al [6] also observed no significant difference between frequency of occurrence of urinary stones in Ramadan as compared with the other months of the year. Our study showed that the admission rate for renal colic was not significantly higher in the summer season as against the rest of the year.

In conclusion, urolithiasis is a major health condition that affects people of predominantly productive ages and men more than women. This study demonstrates no significant seasonal pattern in the occurrence of urolithiasis.

   References Top

1.Menon M, Koul H. Clinical review 32: Calcium oxalate nephrolithiasis. J Clin Endocrinol Metab 1992;74:703-7.  Back to cited text no. 1
2.Ramello A, Vitale C, Marangella M. Epidemiology of nephrolithiasis. J Nephrol 2000;13: 45-50.  Back to cited text no. 2
3.Kim H, Jo MK, Kwak C, et al. Prevalence and epidemiologic characteristics of urolithiasis in Seoul, Korea. Urology 2002;59:517-21.  Back to cited text no. 3
4.Lee YH, Huang WC, Tsai JY, et al. Epidemiological studies on the prevalence of upper urinary calculi in Taiwan. Urol Int 2002;68: 172-7.  Back to cited text no. 4
5.Hallson PC, Rose GA. Seasonal variations in urinary crystals. Br J Urol 1977;49:227-84.  Back to cited text no. 5
6.Basiri A, Moghaddam SM, Khoddam R, Nejad ST, Hakimi A. Monthly variation of urinary stone colic in Iran and its relationship to the fasting month of Ramandan. J Pak Med Assoc 2004;54:6-8.  Back to cited text no. 6
7.Hussain E, Billimora FR, Singh PP. Urolithiasis in Northeast Bombay: Seasonal prevalence and chemical composition of stones. Int Urol Nephrol 1990;22:119-24.  Back to cited text no. 7
8.Trinchieri A. Epidemiology of urolithiasis. Arch Ital Urol Androl 1996;68:203-49.  Back to cited text no. 8
9.Jujitak K. Influence of the weather on ureteral stone colic. Nippon Jinzo Gakkai Shi 1998;30: 297-304.  Back to cited text no. 9
10.Trinchieri A, Mandressi A, Luongo P. The influence of diet on urinary risk factors for stones in healthy subjects and idiopathic renal calcium stone formers. Br J Urol 1991;67:230-6.  Back to cited text no. 10
11.Elomaa I, Karonen SL, Kairento AL. Seasonal variation of urinary calcium and oxalate excretion, serum 25 (OH) D3 and albumin level in relation to renal stone formation. Scand J Urol Nephrol 1982;16:156-61.  Back to cited text no. 11
12.Al-Hadramy MS. Seasonal variations of urinary stone colic in Arabia. J Pak Med Assoc 1997;47:281-4.  Back to cited text no. 12
13.Ramirez TC, Sanchez-Ortiz NA, Gomez ZA. Seasonal effect of age, sex and drinking water composition on nephritic colic. Arch Esp Urol 1981;34:273-88.  Back to cited text no. 13
14.Naas T, Al-Agili S, Bashir O. Urinary calculi: Bacteriological and chemical association. East Mediterr Health J 2001;7:756-62.  Back to cited text no. 14
15.Fetter TR. Statistical analysis of patients with ureteral calculi. JAMA 1963;186:21-3.  Back to cited text no. 15
16.Kassimi MA, Abdul-Halim R, Hardy MJ. The problem of urinary stones in western region of Saudi Arabia. Saudi Med J 1986;7:349-401.  Back to cited text no. 16
17.Hanash KA, Bissada NK, Woodhouse NJ. Pattern of calcium metabolism in normo- and hypercalciuric patients with calcium urolithiasis in Saudi Arabia. Urology 1985;26:27-32.  Back to cited text no. 17
18.Abomelha MS. Extracorporeal shock wave lithotripsy: The first experience in Middle East. Saudi Med J 1986;7:581-8.  Back to cited text no. 18
19.Scales CD Jr, Curtis LH, Norris RD, et al. Changing gender prevalence of stone disease. J Urol 2007;177:979-82.  Back to cited text no. 19
20.Dall'Era JE, Kim F, Chandhoke PS. Gender differences among Hispanics and Caucasians in symptomatic presentation of kidney and ureteral stones. J Endourol 2005;19:283-6.  Back to cited text no. 20
21.Safarinejad MR. Adult urolithiasis in a population-based study in Iran: Prevalence, incidence, and associated risk factors. Urol Res 2007;35:73-82.  Back to cited text no. 21
22.Tanthanuch M, Apiwatgaroon A, Pripatnanont C. Urinary tract calculi in southern Thailand. J Med Assoc Thai 2005;88:80-5.  Back to cited text no. 22
23.Qaader DS, Yousif SY, Mahdi LK. Prevalence and etiology of urinary stones in hospitalized patients in Baghdad. East Mediterr Health J 2006;12:853-61.  Back to cited text no. 23
24.Lieske JC, Peña de la Vega LS, Slezak JM, et al. Renal stone epidemiology in Rochester, Minnesota: An update. Kidney Int 2006;69: 760-4.  Back to cited text no. 24
25.Almby B, Meirik O, Schonebeck J. Incidence, morbidity and complications of renal and ureteral calculi in a well defined geographical area. Scand J Urol Nephrol 1975;9:249-53.  Back to cited text no. 25
26.Juuti M, Heinonen OP. Incidence of urolithiasis leading to hospitalization in Finland. Acta medica scandinavica 1979;206:397-404.  Back to cited text no. 26
27.Khan AS, Rai ME, Pervaiz A, et al. Epidemiological risk factors and composition of urinary stones in Riyadh Saudi Arabia. J Ayub Med Coll 2004;16:56-8.  Back to cited text no. 27
28.Chauhan V, Eskin B, Allegra JR, Cochrane DG. Effect of season, age, and gender on renal colic incidence. Am J Emerg Med 2004;22:560-3.  Back to cited text no. 28
29.Chen YK, Lin HC, Chen CS, Yeh SD. Seasonal variations in urinary calculi attacks and their association with climate: A Population based study. J Urol 2008;179:564-9.  Back to cited text no. 29
30.Cramer JS, Forrest K. Renal lithiasis: Addressing the risks of austere desert deployments. Aviation Space Environ Med 2006;77:649-53.  Back to cited text no. 30
31.Pierce LW, Bloom B. Observations on urolithiasis among American troops in a desert area. J Urol 1945;54:466-70.  Back to cited text no. 31
32.Davidson PJ, Sheerin IG, Frampton C. Renal stone disease in Christchurch, New Zealand. Part 1: presentation and epidemiology. N Z Med J 2009;122:49-56.  Back to cited text no. 32
33.Pincus S, MacBean C, Taylor D. The effects of temperature, age and sex on presentations of renal colic in Melbourne, Australia. Eur J Emerg Med 2010;17:328-31.  Back to cited text no. 33
34.Baker PW, Coyle P, Bais R, Rofe AM. Influence of season, age and sex on renal stone formation in south Australia. Med J Aust 1993;159:390-2.  Back to cited text no. 34

Correspondence Address:
Jayadevan Sreedharan
Assistant Director, Research Division, Gulf Medical University, Ajman
United Arab Emirates
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1319-2442.103565

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