Brick tea consumption as the cause of dental fluorosis among children from Mongol, Kazak and Yugu populations in China.

Dietary fluoride intake and the prevalence of dental fluorosis were investigated in children from three population groups (mongol, Kazak and Yugu) in Gansu Province, China. The concentration of fluoride in drinking water ranged from 0.11 to 0.32 mg/litre; there was no other fluoride pollution. There was a high prevalence of dental fluorosis-52, 84 and 76% among the Mongol, Kazak and Yugu children, respectively). Dental fluorosis was particularly severe among the Kazak population (severity index: 2.00, 3.05 and 2.57 among the three populations, respectively). Each of the population groups had a long tradition of drinking milk tea made from brick tea water. This milk tea was found to contain high concentrations of fluoride (2.58-3.69 mg/litre). The daily fluorine consumption was 1.36-2.42-times the US RDA of 2.5 mg for children. Regression analysis showed that fluorosis was significantly correlated with the consumption of milk tea made from brick tea water, but not with any other dietary component (including milk).