Serum α-Tocopherol Has a Nonlinear Inverse Association with Periodontitis among US Adults

Background: Previous experimental models suggest that vitamin E may ameliorate periodontitis. However, epidemiologic studies show inconsistent evidence in supporting this plausible association. Objective: We investigated the association between serum alpha-tocopherol (alpha T) and gamma-tocopherol (gamma T) and periodontitis in a large cross-sectional US population. Methods: This study included 4708 participants in the 1999-2001 NHANES. Serum tocopherols were measured by HPLC and values were adjusted by total cholesterol (TC). Periodontal status was assessed by mean clinical attachment loss (CAL) and probing pocket depth (PPD). Total periodontitis (TPD) was defined as the sum of mild, moderate, and severe periodontitis. All measurements were performed by NHANES. Results: Means +/- SDs of serum alpha T:TC ratio from low to high quartiles were 4.0 +/- 0.4, 4.8 +/- 0.2, 5.7 +/- 0.4, and 9.1 +/- 2.7 mu mol/mmol. In multivariate regression models, alpha T:TC quartiles were inversely associated with mean CAL (P-trend = 0.06), mean PPD (P-trend <0.001), and TPD (P-trend <0.001) overall. Adjusted mean differences (95% Cls) between the first and fourth quartile of alpha T: TC were 0.12 mm (0.03, 0.20; P-difference = 0.005) for mean CAL and 0.12 mm (0.06, 0.17; P-difference <0.001) for mean PPD, whereas the corresponding OR for TPD was 1.65 (95% Cl: 1.26, 2.16; P-difference = 0.001). In a dose-response analysis, a clear inverse association between alpha T:TC and mean CAL, mean PPD, and TPD was observed among participants with relatively low alpha T:TC. No differences were seen in participants with higher alpha T:TC ratios. Participaints with gamma T:TC ratio in the interquartile range showed a significantly lower mean PPD than those in the highest quartile. Conclusions: A nonlinear inverse association was observed between serum alpha T and severity of periodontitis, which was restricted to adults with normal but relatively low alpha T status. These findings warrant further confirmation in longitudinal or intervention studies.