RÉSUMÉ
Objective To evaluate the effect of serum chromium on oral cancer after adjusting the covarite between groups based on propensity score matching (PSM). Methods We performed a case-control study in 395 cases of newly diagnosed primary oral cancer from the First Affiliated Hospital of Fujian Medical University and 1 240 controls from the same community from January 2010 to February 2018. Using the PSM to select 309 controls randomly which were matched with the cases by 1 ∶1 matching. Conditional Logistic regression model was used to explore the association between chromium and oral cancer. Results The level of serum chromium was 178.91 (121.83-284.19) μg/L in the case group, which was lower than 324.27 (264.82-397.69) μg/L in control group, the difference was statistically significant (P＜0.001). Dose-response analysis showed that the risk of oral cancer gradually decreased with the increase of serum chromium, which presented a negative correlation. There was a negative correlation between serum chromium level and the risk for oral cancer by conditional Logistic regression,the aOR of serum chromium in the Q2, Q3 and Q4 compared with the Q1 were 0.14 (0.08-0.26), 0.15 (0.08-0.28) and 0.10 (0.05-0.20),with significant trend (Ptrend＜0.001). Stratified analysis showed the negative correlation between serum chromium and oral cancer by smoking, drinking tea, not drinking alcohol status and fish, fruits and green vegetables intake frequencies. Conclusions The high level of serum chromium is a protective factor for the incidence of oral cancer, and the higher of serum chromium, the lower risk of developing oral cancer.