Crystalline composition and etiologic factors of kidney stone in Thailand : update 2007.

Objective: The etiology of kidney stone is multifactorial including environmental, behavioral and genetic. Insights about predisposing causes and mineral composition are mandatory for better management of kidney stone disease. The present hospital-based study aims to explore the mineral constituents and etiologic risks of kidney stones in Thai patients from the four geographic regions of the country. Method: Two hundred and fifty six kidney stone patients from four geographic regions of Thailand, including the northeastern (n=103), the northern (n=81), the central (n=47) and the southern (n=25) were recruited in this study. Of these, 144 patients completed the food frequency questionnaire to assess the kidney stone risk. Mineral composition of stones were analyzed by Fourier transformed infrared spectrometry. Results: Kidney stone frequently affected peoples aged 40-49 years. Only 31.9 % of patients had a positive family history of renal stone. Calcium oxalate (CaOx) stone was the most prevalent type (73.8 %). Uric acid (UA) stone was found in 16.0 % commonly affected peoples aged 60-70 years. Mixed stones, notably CaOx mixed with calcium phosphate (CaP), were more prevalent than pure stones. The food frequency questionnaire data showed that 59.7 % of stone patients consumed less than two liters of water per day. Low intakes of fruits and vegetables were notably present. In contrast, high consumption of rice was observed in over 65 % of stone patients. Conclusion: CaOx mixed with CaP was the most prevalent stone type. UA stone was more likely to occur in the elderly. Kidney stone patients were found to consume less-than-adequate amounts of water, food high in carbohydrates, along with low consumtion of fruits and vegetables. These dietary habits might be risk factors in stone development among the Thai population.