Could Consumption of Trace Element-Contaminated Rice Be a Risk Factor for Acute Interstitial Nephritis with Uncertain Etiology in the Dry Zone of Sri Lanka?

Ingestion of toxic trace elements in the human body has been considered one of the major reasons for renal dysfunction. Chronic kidney disease with uncertain etiological factors (CKDu) is a recently described clinical entity in which the disease is found in geographically isolated pockets in the dry zone of Sri Lanka. In CKDu regions, an increasing number of cases are reported with acute interstitial nephritis without any known reason (AINu). However, recent exposure to certain risk behaviors or nephrotoxins, or both, is suspected for the AINu. Consumption of foods that are contaminated with trace elements is one of the main pathways of human exposure to environmental toxins. The current study was carried out to assess the possibility of trace element-contaminated rice consumption on the etiopathogenesis of AINu. Samples of rice consumed by 32 clinically diagnosed AINu cases were collected and analyzed for possible nephrotoxic trace elements. Out of 32 patients, 26 were histologically confirmed with tubulointerstitial disease. The results revealed that the mean values of Cd, As, and Pb were 0.18, 0.055, and 0.135 mg/kg, with ranges of 0.020-1.06, 0.012-0.222, and 0.003-0.744 mg/kg (on dry weight basis), respectively. This study indicated that the investigated toxic trace element levels of rice consumed by AINu were reasonably below the recommended levels of the Codex Alimentarius Commission of FAO and WHO. Hence, it is less likely that rice consumption is to be a risk factor for the etiology of AINu.