GDF15 and diabetes mellitus: The HR for diabetes in the fourth compared with the first quartile of GDF-15 was 1.30 (95% CI 1.01, 1.67; p for trend = 0.061), but the association between GDF-15 (in SD units) and diabetes remained significant (HR 1.12; 95% CI 1.02, 1.23; p = 0.015).