The Association between Leptin Level and Breast Cancer: A Meta-Analysis

Background: Contradictory results have been reported regarding the association between leptin level and breast cancer. Therefore, a meta-analysis was performed to investigate this issue. Methods: Published literature from PubMed and the Chinese National Knowledge Infrastructure (CNKI) Database was retrieved. This study was performed based on different cases and control groups. The combined effect ((d) over bar) with 95% confidence interval (Cl) was calculated using fixed-effects or random-effects model analysis. Results: Overall, the mean serum leptin level of case groups was significantly higher than that of control groups. A) For 9 studies comparing breast cancer cases and healthy controls the combined effect (d) over bar was 0.58 with 95% Cl (0.48, 0.68). B) For 4 studies comparing premenopausal breast cancer cases and healthy controls the (d) over bar was 0.32 (0.12, 0.52). C) For 5 studies comparing postmenopausal cases and healthy controls the (d) over bar was 0.65 (0.46, 0.84). D) For 4 studies comparing breast cancer cases and breast benign controls the (d) over bar was 0.38 (0.17, 0.59). E) For 2 studies comparing premenopausal breast cancer cases and breast benign controls the (d) over bar was 0.33 (-0.25, 0.91). F) For 6 studies comparing postmenopausal breast cancer cases and breast benign controls the (d) over bar was 0.39 (0.19, 0.60). G) For 4 studies comparing lymph node metastasis positive cases and negative controls the (d) over bar was 0.72 (0.45, 1.00). H) For 3 studies comparing breast benign cases and healthy controls the (d) over bar was 0.71 (0.41, 1.01). Conclusion: This meta-analysis suggests that leptin level plays a role in breast cancer and has potential for development as a diagnostic tool.