Epidemiological data regarding Balkan endemic nephropathy in relationship with the Pliocene coal etiological hypothesis.

Balkan Endemic nephropathy (BEN) is a tubulointerstitial disease of unknown etiology signaled in a limited geographical area. In the neighbourhood of endemic villages are coal deposits from the Pliocene, that contain toxic substances that by mobilizing groundwater can leach in water sources used by the inhabitants. In the present paper the possible impact of the coal from Pliocene on people that worked many years in mines in the endemic County Mehedinti, Romania, and who lived in this area are analysed. The risk of toxicity of coal was theoretically increased in miners because they consumed frequently water from mine springs that came from coal layers, while at home water from wells could have been contaminated by toxic substances from coal. It has been found that only 5 of the 96 patients with BEN were under dialysis program in 2008. Also out of 34 former miners only 3 had GFR < 60 ml/min/1.73 sqm, and only one with creatinine of 3 mg/dl had GFR < 30 ml/min/1.73 sqm. The mean GFR in the 34 miners was: 94.13 +/- 26.58 ml/min/1.73 sqm. We analysed GFR and proteinuria in persons from the endemic zone from 2 types of villages: some with mining activity presently (Husnicioara) others where presently there are no mining activities (Hinova, Bistrita, Livezile). We also analysed comparatively 2 non-endemic localities near the endemic focus: Drobeta Turnu Severin (without mining activity) and Motru with mining activity where different coal deposits are (non-Pliocene). Data were provided from the family doctors databases. The GFR was lower in the inhabitants from the endemic villages Bistrita and Hinova than in the investigated inhabitants from the non-endemic town Drobeta Turnu Severin (p = 0.008 and p = 0.0004 respectively). Inhabitants from the endemic village Husnicioara (Pliocene coal mine still functioning) had a higher GFR than inhabitants from Drobeta Turnu Severin and higher than inhabitants from the endemic village Livezile (mine closed 10 years ago): p = 0.0055 and p = 0.001 respectively, but a lower than the investigated inhabitants from the non-endemic town Motru (where a non-Pliocene coal mine is functioning): p < 0.001. Proteinuria was present in 8.03% of the inhabitants from the endemic village Bistrita and in 7.4% of the inhabitants from the endemic village Hinova. In the non-endemic town Drobeta Turnu Severin, proteinuria was present in 7.08% of the investigated inhabitants. Proteinuria was present in 0.78% of the investigated inhabitants of the non-endemic town Motru (where a non-Pliocene coal mine is functioning) and 2.5% of the inhabitants of the endemic village Husnicioara (Pliocene coal mine still functioning). Our paper does not show any relationship between exposure to Pliocene coal and the etiology of BEN.