Uranium mine proximity, immune function, and Helicobacter pylori infection in Tajikistan

Tajikistan is a country with numerous abandoned uranium mines and individuals residing in close proximity to these sites. Inspection of one of these sites next to the town of Taboshar revealed uncontrolled waste with elevated radiation levels. Convenience samples of subjects likely to have been exposed to uranium mining (i.e., combined living near wastes and former miners) and unexposed subjects (living far from mines and never working in mining) were recruited. There was a higher prevelance of Helicobacter pylori (H. pylori) infection among the exposed and there were significantly more virulent infections involving CagA. Histolological examination of the stomach showed more gastric atrophy in the exposed group. Exposed individuals also had lower percentage of T lymphocytes, fewer T-helper cells, significant imbalance in the immunoregulation index, and significantly higher levels of cytotoxic lymphocytes. There were also reduced levels of immunoglobulin (Ig) M and IgG in the exposed group. These findings are consistent with adverse effects on immune functioning that might increase the rate of development of infectious disease, However, lack of control for confounding factors and lack of individual exposure assessment limit conclusions that can be drawn. Further research that addresses these limitations of this analysis is needed.