High Serum Level of Retinol and α-Tocopherol Affords Protection Against Oral Cancer in a Multiethnic Population

Background: A comparative cross-sectional study involving oral cancer patients and healthy individuals was designed to investigate associations between retinol, ${\alpha}$-tocopherol and ${\beta}$-carotene with the risk of oral cancer. Materials and Methods: This study included a total of 240 matched cases and controls where subjects were selected from the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). Retinol, ${\alpha}$-tocopherol and ${\beta}$-carotene levels and intake were examined by high-performance liquid chromatography (HPLC) and food frequency questionnaire (FFQ) respectively. Results: It was found that results from the two methods applied did not correlate, so that further analysis was done using the HPLC method utilising blood serum. Serum levels of retinol and ${\alpha}$-tocopherol among cases ($0.177{\pm}0.081$, $1.649{\pm}1.670{\mu}g/ml$) were significantly lower than in controls ($0.264{\pm}0.137$, $3.225{\pm}2.054{\mu}g/ml$) (p<0.005). Although serum level of ${\beta}$-carotene among cases ($0.106{\pm}0.159{\mu}g/ml$) were lower compared to controls ($0.134{\pm}0.131{\mu}g/ml$), statistical significance was not observed. Logistic regression analysis showed that high serum level of retinol (OR=0.501, 95% CI=0.254-0.992, p<0.05) and ${\alpha}$-tocopherol (OR=0.184, 95% CI=0.091-0.370, p<0.05) was significantly related to lower risk of oral cancer, whereas no relationship was observed between ${\beta}$-carotene and oral cancer risk. Conclusions: High serum levels of retinol and ${\alpha}$-tocopherol confer protection against oral cancer risk.