PMCH and type 2 diabetes mellitus: Genetically predicted MCH and MCV levels were significantly associated with decreased risk of T2D with an ORIVW per SD change of 0.934 (95% CI: 0.891–0.98; PIVW = 0.003) and 0.902 (95% CI: 0.857–0.949; PIVW = 0.00008) respectively.