Epidemiological evaluation of recurrent stomatitis, nitrates in drinking water, and cytochrome b5 reductase activity.

OBJECTIVE: Our aim was to examine a possible correlation between drinking water nitrate concentration, recurrent stomatitis, and cytochrome b5 reductase activity. Dietary nitrate can form nitrite in vivo. This can cause methemoglobinemia in the red blood cells. Cytochrome b5 reductase is an enzyme in the red blood cells that reduces methemoglobin back to hemoglobin.

METHODS: Five areas were selected in the State of Rajasthan, India, having drinking water nitrate concentration (as nitrate) of 26, 45, 95, 222, and 459 mg of NO3/L. House schedules were prepared in these areas in accordance with a statistically designed protocol. We selected 193 age- and weight-matched persons, representing 10% of the total population in each of these areas. Detailed history was taken for recurrent stomatitis, medical examination was conducted, and blood samples were taken to ascertain cytochrome b5 reductase activity in the selected population. Collected data were statistically analyzed to ascertain a relationship between nitrate concentration, cytochrome b5 reductase activity, and percent stomatitis, using Microsoft Excel software.

RESULTS: This study suggests that there is a significant interdependence between drinking water nitrate concentration, cytochrome b5 reductase activity, and recurrent stomatitis.

CONCLUSION: Increased cytochrome b5 reductase activity primarily induced by the presence of high nitrate concentration in drinking water could be the cause for recurrent stomatitis.