| Cellular study |
1. Metformin inhibits proliferation of benign prostate epithelial cell by reducing the expression of insulin-like growth factor 1 (IGF-1) and IGF-1 receptor and by regulating the cell cycle [83]. |
| Animal studies |
1. Metformin attenuates BPH induced by testosterone [85] or by metabolic syndrome [86] in male Sprague-Dawley rats, probably via a potential involvement of the suppression of the IGF-1 pathway. |
| Human studies |
1. A retrospective cohort study conducted in the USA estimated a hazard ratio for BPH for metformin vs. sulfonylureas of 0.99 (95% confidence interval, 0.94–1.03) [87]. |
| 2. A retrospective cohort study conducted in Korea estimated a hazard ratio for BPH progression indicated by the occurrence of prostatectomy for metformin use in patients with type 2 diabetes mellitus vs. non-diabetic control of 0.86 (95% confidence interval, 0.77–0.96; p=0.007) [88]. |
| Author’s comments |
1. Cellular and animal studies support a potential beneficial effect of metformin on BPH, but results from human studies are not consistent. |
| 2. Metformin may have a direct beneficial effect on BPH by inhibiting the IGF-1 pathway or an indirect effect via improving insulin resistance and metablic syndrome. |
| 3. Intestersted readers may refer to a review article by Wang and Olumi [84]. |
