Non-Linear Association of Relationship Between Serum Vitamin E and Eczema in US Adults

Eczema is an inflammatory skin disorder that influences 10%-20% of the global population. Previous research has shown that vitamin E supplementation may alleviate eczema symptoms, but the relationship between serum vitamin E and eczema incidence remains unclear. This study was a cross-sectional analysis utilizing data from the 2005-2006 US National Health and Nutrition Examination Survey (NHANES). We included data from adult participants who were surveyed for eczema and tested for vitamin E. Multivariate logistic regression models were employed to investigate the relationship between serum vitamin E levels and eczema. The generalized additive model (GAM) was employed to investigate the nonlinear relationship, while a two-piecewise linear regression model was utilized to identify the inflection point. The analysis included 4433 adults. The prevalence of eczema was 7.65%. The mean serum vitamin E concentration was 29.18 μmol/L (95% CI: 28.54-29.83). After adjusting for participants' demographics, way of life, stress, and clinical comorbidity variables, a non-linear association was detected between serum vitamin E and eczema incidence, which had two inflection points for serum vitamin E at 27.4 and 49.5 μmol/L. Serum vitamin E levels < 27.4 μmol/L were positively associated with the eczema incidence (OR = 1.064, 95% CI: 1.024-1.105; p = 0.001), whereas levels between 27.4 and 49.5 μmol/L showed an inverse association (OR = 0.960, 95% CI: 0.934-0.987; p = 0.004). Vitamin E demonstrates a nonlinear association with eczema in US adults. Serum vitamin E levels < 27.4 μmol/L showed a positive association with eczema, whereas levels between 27.4 and 49.5 μmol/L demonstrated an inverse association.