Effects of tibolone and combined 17beta-estradiol and norethisterone acetate on serum C-reactive protein in healthy post-menopausal women: a randomized trial.
BACKGROUND
Serum C-reactive protein (CRP) is an independent risk factor for the development of cardiovascular diseases in healthy post-menopausal women. Oral unopposed and progestin-combined 17beta-estradiol (E(2)) increase serum CRP in post-menopausal women. The aim of this study was to compare the effects of tibolone, a steroid with estrogenic, androgenic or progestogenic properties, with a combination of E(2) and norethisterone acetate (E(2) + NETA) on serum CRP levels in healthy post-menopausal women.


METHODS
A total of 139 post-menopausal women (mean age: 55 years, range 44-48) was randomly assigned to receive tibolone 1.25 mg/day (n = 52), tibolone 2.5 mg/day (n = 39) or E(2) 2 mg/day plus NETA 1 mg/day (n = 48) for 2 years. Serum CRP was measured at baseline and at 6, 12 and 24 months.


RESULTS
Both doses of tibolone and E(2) + NETA increased serum CRP by a similar extent as soon as 6 months with a sustained effect over the 24 month treatment period. For example, after 6 months of treatment, serum CRP increased by a median of +106% (P < 0.001), +89% (P < 0.05) and +139% (P < 0.001) for tibolone 1.25 mg/day, tibolone 2.5 mg/day and E(2) + NETA respectively.


CONCLUSIONS
Tibolone and E(2) + NETA significantly increase serum CRP levels in healthy post-menopausal women to a comparable extent. Relationships between induced elevated CRP levels with tibolone and E(2) + NETA and cardiovascular events require further studies.
D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis*; D004958:Estradiol / Q000008:administration & dosage*; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D009640:Norethindrone / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D000077563:Norethindrone Acetate; D009652:Norpregnenes / Q000008:administration & dosage*; D017698:Postmenopause; D015430:Weight Gain
D009652:Norpregnenes; D004958:Estradiol; D002097:C-Reactive Protein; D000077563:Norethindrone Acetate; C027385:tibolone; D009640:Norethindrone