Objective: To evaluate the effect of continuous combined hormone therapy (HT), tibolone and raloxifene on circulating vascular endothelial growth factor (VEGF) in postmenopausal women.
Design: One-year prospective intervention study.
Methods: One hundred and forty-six postmenopausal women with a mean age of 51.8+/-4.1 (s.d.) years received 0.625 mg conjugated equine estrogen (CEE) plus 5 mg medroxyprogesterone acetate (MPA) (CEE/MPA, n=34), 2.5 mg tibolone (n=37), 60 mg raloxifene (n=40) or no active treatment (control group, n=35). Plasma VEGF was estimated at baseline and at 6 and 12 months.
Results: In both the CEE/MPA-treated and the tibolone-treated groups plasma VEGF increased significantly at month 6 and remained elevated at month 12 (CEE/MPA baseline: 268.1+/-187.8 pg/ml, month 6: 320.0+/-175.3 pg/ml, month 12: 321.1+/-181.8 pg/ml, P=0.01; tibolone baseline: 240.6+/-165.8 pg/ml, month 6: 271.4+/-172.7 pg/ml, month 12: 274.8+/-183.1 pg/ml, P=0.03). These changes were significantly different from the respective changes in the control group after adjusting for T-score in bone densitometry (CEE/MPA: P=0.02, tibolone: P=0.04). The effect of HT or tibolone on plasma VEGF was mainly evident in women with low baseline VEGF levels (<243.2 pg/ml, median for whole sample). On the contrary, VEGF levels in the raloxifene-treated or the control group did not change throughout the study.
Conclusion: Both continuous combined HT and tibolone increased circulating VEGF in postmenopausal women, while raloxifene had no effect. Further research is needed to clarify the clinical relevance of these findings with respect to cardiovascular risk in postmenopausal women.