In this paper, urolithiasis is remarked from the standpoint of descriptive epidemiology, which examines the frequency distribution of a given disease in a population in terms of time, place and personal characteristics with an aim of identifying risk factors or some clues to the etiology. Some descriptive epidemiological features of urolithiasis are summarized. Prevalence rate is around 4% (4-15% in males and 4-8% in females), and incidence rate varies from area to area: 53.2 per 100,000 population in 1975 in Japan, 364 in 1976 in Malaysia, and 540 in 1979 in West Germany. Prevalence and/or incidence rates have, in general, increased in the developed countries since World War II and in the developing countries as well, where upward trends are quite analogous to the trends observed in the nineteenth century in Europe. Recurrence rate, which is much higher in males than in females, ranges from 31% to 75%, depending on the follow-up periods. In the industrialized countries, upper urinary (renal and ureteral) stones account for more than 90% of total stones, which are ordinarily calcium complexes in composition. More common in the developing countries are lower urinary (bladder and urethral) stones, frequently composed of magnesium ammonium phosphate, which indicates a close association with urinary tract infections. Variations in frequency are evident by season and by region within a country. Age and sex differentials in urinary stone formers are substantial: more common in males 30-40 years old in the industrialized countries and in children under 10 years old in the developing countries. Racial differentials are also noted; blacks appear to suffer less frequently than whites. Stone formers experience more frequent episodes of stone formation in their family members, particularly father and brothers, than non-stone formers. These findings on racial differentials and family preponderance suggest the possible relevance of genetic factors in stone formation. Stone formers are more likely to be occupationally sedentary and socially affluent. This observation and differentials by age and sex suggest the probable relevance of lifestyle and environmental factors in stone formation. Epidemiological factors incriminated for stone formation will be discussed in a separate paper.
74 cases of radiologically proven urinary calculi between 1975 and 1979 were analysed by race, sex and age. The relative frequency of single and multiple stones was also studied. The disease was found in all the ethnic groups present in Limbang except for the Punans. Possible reasons for this observation of their apparent absence were given. The absence of patients from one of the Malay Kampongs in Limbang town was also noted.
A study into the incidence of urinary calculi over a 15-year period from 1962-1976 in the states of mainland Malaysia is presented. Figures from the Ministry of Health Returns are the only source for such information. The incidence from the various states over each five year period from 1962-1972 is tabulated and its significance especially, the pattern of incidence, and its relation to industrialisation is discussed. Malaysia is beginning to show the same pattern of incidence in the upper and lower urinary tract as that of other industrialised countries. A plea is made for the establishment of a central register at the Institute of Urology and Nephrology to carry out a national survey of urinary calculi so that a study into the epidemiology, and if possible, preventive aspects of urolithiasis can be undertaken.
Xanthogranulomatous pyelonephritis is a clinico-pathological entity that is gaining awareness amongst urologists worldwide. It is an unusual chronic inflammatory lesion involving the kidney that destroys renal parenchyma and may mimic renal carcinoma. It is usually seen in middle-aged women and is associated with urinary tract infections and urinary calculi. Most reports and reviews of this condition come from the West; this study reviews the incidence and presentation of the condition in a Malaysian population.
Urolithiasis is a common disease with increasing incidence and prevalence world-wide, probably more common in industrialized countries. The metabolic evaluation of 24-h urine collection has been considered as part of the management of urinary stone patients. The aim of this study was to evaluate the 24-h urine constituents in stone formers and its relation to demographic data in the northeast part of Peninsular Malaysia. One hundred and six patients were recruited in this study from two hospitals in the same geographical region; 96 patients fulfilled the inclusion criteria and an informed consent was obtained from all subjects. The 24-h urine was collected in sterile bottles with a preservative agent and calcium, oxalate, citrate, uric acid, magnesium and phosphate were tested using commercial kits on a Roche Hitachi 912 chemistry analyzer. The age (mean ± SD) of 96 patients was 56.45 ± 13.43 years and 82.3% of the patients were male while 17.7% were female. The 24-h urine abnormalities were hypercalciuria (14.5%), hyperoxaluria (61.4%), hypocitraturia (57.2%), hyperuricouria (19.7%), hypomagnesuria (59.3%) and hyperphosphaturia (12.5%). Hyperoxaluria (61.4%) was the most common abnormality detected during the analysis of 24-h urine constituents in contradiction to industrial countries, where hypercalciuria was the most common finding. The high frequencies of hypomagnesuria and hypocitraturia reflect the important role of magnesium and citrate in stone formation and their prophylactic role in the treatment of urinary stone disease in the given population.