Another case–control study in a Greek cohort of 144 patients aged ≥65 years with pre-diabetes and 81 healthy age-matched controls reported that individuals with 25(OH)D <50 nmol/L and PTH ≥40 pg/mL had significantly higher fasting plasma glucose levels than those with either 25(OH)D ≥50 nmol/L or PTH <40 pg/mL or both, after adjustment for age, sex, BMI, and season of sampling [22]. This evidence concerns the gene PTH and diabetes mellitus.