Fig. 2

Restricted cubic spline multivariable logistic model of the association between blood levels of trace elements and ESCC risk. The solid red line represents the multivariable-adjusted odds ratio (OR), with the shaded portions showing the 95% confidence interval (CI). The black dashed line represents the reference line for no association at a OR of 1.0. The inflection points are the medians of the levels of trace elements in controls. Models were adjusted for gender and age.