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 ([Formula: see text]) with 95% confidence interval (CI) 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 [Formula: see text] was 0.58 with 95% CI (0.48, 0.68). B) For 4 studies comparing premenopausal breast cancer cases and healthy controls the [Formula: see text] was 0.32 (0.12, 0.52). C) For 5 studies comparing postmenopausal cases and healthy controls the [Formula: see text] was 0.65 (0.46, 0.84). D) For 4 studies comparing breast cancer cases and breast benign controls the [Formula: see text] was 0.38 (0.17, 0.59). E) For 2 studies comparing premenopausal breast cancer cases and breast benign controls the [Formula: see text] was 0.33 (-0.25, 0.91). F) For 6 studies comparing postmenopausal breast cancer cases and breast benign controls the [Formula: see text] was 0.39 (0.19, 0.60). G) For 4 studies comparing lymph node metastasis positive cases and negative controls the [Formula: see text] was 0.72 (0.45, 1.00). H) For 3 studies comparing breast benign cases and healthy controls the [Formula: see text] 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.