Endometrial cancer risk is strongly influenced by obesity, but the mechanisms of action remain unclear. Leptin and adiponectin, secreted from adipose tissue, reportedly play a role in such carcinogenic processes as cell proliferation, angiogenesis, and insulin regulation. In this case–control study, nested within the Breast and Bone Follow-up of the Fracture Intervention Trial (n=15 595), we assessed pre-diagnostic serum leptin, total adiponectin, and high-molecular-weight (HMW) adiponectin in relation to endometrial cancer among postmenopausal women. During the 10-year follow-up, 62 incident endometrial cases were identified and matched to 124 controls on age, geographical site, time of fasting blood draw at baseline (1992–1993), and trial participation status. Adipokines and C-peptide were measured by ELISA. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated via conditional logistic regression, with exposures categorized in tertiles (T). Multivariable models considered C-peptide, BMI (kg/m2), and estradiol (E2) as potential confounders. Endometrial cancer risk was significantly associated with higher leptin levels, adjusted for E2 and C-peptide (ORT3 vs T1=2.96; 95% CI, 1.21–7.25; P trend <0.01). After further adjustment for BMI, the estimates were attenuated and the positive trend was no longer statistically significant (ORT3 vs T1=2.11; 95% CI, 0.69–6.44; P trend=0.18). No significant associations were observed with adiponectin or HMW adiponectin and endometrial cancer. Our findings with leptin suggest that the leptin–BMI axis might increase endometrial cancer risk through mechanisms other than estrogen-driven proliferation. Continued exploration of these pathways in larger prospective studies may help elucidate mechanisms underlying observed obesity–endometrial cancer associations.
Sensitivity of transvaginal ultrasound screening for endometrial cancer in postmenopausal women: a case-control study within the UKCTOCS cohort
