A case–control study on environmental and biological risk factors for renal calculi persisting in a coastal Union Territory, India

BACKGROUND AND OBJECTIVES: Renal stone disease is a common disorder of the urinary tract and also a significant problem because of incidence, recurrence, and severe consequences. The complex pathogenetic mechanisms of renal stone formation involve both biologic and environmental risk factors. The present study was performed to identify the role of these parameters among renal stone patients and normal individuals from a coastal union territory region in South India. METHODS: The authors conducted a case–control study of renal stone disease among outpatient department patients more than 30 years of age using systematic random sampling procedure with 100 study participants (50 subjects for each group). A questionnaire to explore some relevant history as well as to note general examination findings was used along with a house visit to collect a sample of water. Analysis was undertaken using appropriate statistical techniques. RESULTS: The study showed statistically significant association for renal stones with female sex, illiteracy, body mass index (BMI) (>25 kg/m(2)), sodium (>50 mg/L), water consumption (<1.5 L/day), water source being borewell, consuming soft drink, sedentary work, and family history of renal stones. The adjusted odds ratios (ORs) were significantly higher for consuming soft drink (OR: 8.19; 95% confidence interval: 1.99–33.69), sedentary work (10.01; 1.27–78.91), and water consumption < 1.5 L/day (7.73; 2.24–26.69). INTERPRETATION AND CONCLUSIONS: We conclude that in this part of India, female gender, illiteracy, high BMI, high sodium in drinking water, inadequate water consumption, borewell drinking water, soft-drink consumption, sedentary work, and family history of renal stones can lead to a significant increase in the risk of renal stone disease.