Associations of plasma sphingolipids with measures of insulin sensitivity, β-cell function, and incident diabetes in Japanese Americans

•Plasma Ceramides C16:0, C18:0, C20:0, and C22:0 were inversely associated with insulin sensitivity.•Plasma Ceramide C18:0 was associated with the risk of incident diabetes.•The association of plasma Ceramide C18:0 with incident diabetes was partially mediated through decreased insulin sensitivity.•Plasma Ceramide C18:0 could be a potential biomarker for identifying individuals at risk of developing diabetes.