Leptin and insulin growth factor I in relation to breast cancer (Greece)

Objectives: Because both breast cancer and the hormone leptin are associate d with obesity and reproductive phenomena in women, we have examined whethe r there is a relationship between leptin and breast cancer among premenopau sal and postmenopausal women. We have also evaluated in this dataset the as sociation of IGF-I with breast cancer. Methods: Seventy-five cases, diagnosed during mammographic screening, with incident breast cancer were matched for age and type of permanent residence with seventy-five controls from those screened negative in the same study base. Results: There was no evidence for an association between IGF-I and either premenopausal or postmenopausal breast cancer risk or between leptin and po stmenopausal breast cancer. Among premenopausal women, however, there was a strong and statistically significant inverse association of leptin with br east cancer. Conclusion: We did not confirm the positive association, reported from othe r investigations, of IGF-I with premenopausal breast cancer risk. We have f ound evidence, however, that leptin may be inversely related to breast canc er risk among premenopausal women. The latter finding is not biologically i mplausible and deserves to be examined in additional datasets.