Table S2 shows that, in the high urinary fluoride level group, there were more male participants, more smokers, a longer residence duration, and a higher cancer incidence compared to the low and moderate urinary fluoride level groups. CD4+ and CD8+ T-cell counts decreased in a fluoride-dependent manner, suggesting that the immune function of individuals in endemic fluorosis areas may be affected by fluoride exposure. This evidence concerns the gene CD4 and dental fluorosis.