The present study examined factors in subjects diagnosed with hyperglycemia during periodic medical checkups. In total, 9,324 subjects (males: 4,532, females: 4,792) visited the Takagi Hospital for medical checkups in 2019. Eighty-two subjects (59 males) whose fasting blood glucose exceeded 126 mg/dl for the first time during the annual or biannual follow-up were included. Sex- and age-matched controls were used. Data from cases with hyperglycemia were compared to data from themselves one or two years before hyperglycemia. Body mass index (BMI), waist circumference, fatty liver, and blood pressure were higher in cases than in controls. Fasting blood glucose and hemoglobin A1c were higher in cases. Blood test results indicated that triglyceride, low-density lipoprotein (LDL) cholesterol, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and γ-glutamyl transpeptidase (γ-GTP), were significantly enhanced in cases. Multiple logistic regression analysis revealed that BMI, waist circumference, blood pressure, triglyceride, ALT, and γ-GTP were significant independent risk factors for cases with hyperglycemia. These risk factors were already enhanced in the cases of themselves in one or two years before hyperglycemia. In conclusion, BMI, waist circumference, blood pressure, and fatty liver indicated by ALT and γ-GTP were exacerbated concomitant with hyperglycemia, and increases in these factors preceded hyperglycemia.