Suatu kecenderungan peningkatan resiko luka pra-bahaya mulut ditemukan pada vitamin E, terutama di antara perokot dan pada asupan vitamin E. Beta-carotene juga meningkatkan resiko di antara perokok.
A trend for increased risk of oral pre-malignant lesions was observed with vitamin E, especially among current smokers and with vitamin E supplements. Beta-carotene also increased the risk among current smokers.