Table 3.

Risk of prostate cancer according to the number of metformin prescriptions

Metformin exposure (number of prescriptions)Cases (n = 739)Controls (n = 7,359)Crude RRAdjusted RR (95% CI)a
Never, n (%)203 (27.5)2,123 (28.8)1.001.00 (reference)
1–7, n (%)125 (16.9)1,379 (18.7)0.941.05 (0.80–1.37)
7–18, n (%)135 (18.3)1,269 (17.2)1.151.29 (0.99–1.69)
18–36, n (%)141 (19.1)1,310 (17.8)1.191.37 (1.04–1.81)
≥36, n (%)135 (18.3)1,278 (17.4)1.181.40 (1.03–1.89)
  • aAdjusted for HbA1c, excessive alcohol use, obesity, smoking, lower urinary tract symptoms, previous cancer, and use of NSAIDs, antihypertensive drugs, statins, and other antidiabetic agents. P value for trend = 0.04.