Is the staple diet eaten in Medawachchiya, Sri Lanka, a predisposing factor in the development of chronic kidney disease of unknown etiology? - A comparison based on urinary β(2)-microglobulin measurements

BACKGROUND: Exact mechanism of causation of chronic kidney disease of unknown etiology (CKDu) in Sri Lanka is not described to date, despite the identification of possible multiple risk factors. Questions have been raised as to why only some are affected while others remain intact, though they are inhabitants of the same locality. METHODS: Comparative studies were carried out, assessing urinary β(2) microglobulin (β(2)m) and the dietary patterns of CKDu patients and age sex matched non-CKDu subjects. Urinary β2m levels of spot urine samples were analyzed using the Enzyme-linked Immunosorbent assay (ELISA) and dietary patterns were studied using twenty four hour dietary recalls and frequency consumption of foods of animal origin performed on three occasions at six months intervals within a period of one and half years. RESULTS: The mean urinary β(2)m level of CKDu patients from Medawachchiya was significantly (p < 0.05) higher when compared with that of the non-CKDu subjects. The mean urinary β(2)m level of the non-CKDu subjects was within the reference limits for spot urine samples (0 – 0.3 μg/mL). White raw rice was the staple diet of both CKDu patients and non-CKDu subjects and the level of consumption was almost the same. The consumption of fresh water fish products of CKDu patients under high (14, 14%), moderate (36, 36%), low (26, 26%) and less (20, 20%) categories did not show significant variations (p > 0.05) compared to non-CKDu subjects. CONCLUSIONS: Staple food in diet and the consumption pattern of CKDu patients from Medawachchiya were similar to that of non-CKDu subjects from the same area despite their urinary β(2)m concentration being significantly higher.