EFFECTS OF TIBOLONE ON LIPOPROTEIN(A) AND HDL SUBFRACTIONS

Objective: To determine the effects of tibolone, a synthetic steroid u sed to alleviate climacteric symptoms and prevent osteoporosis, on lip oprotein metabolism, with particular reference to lipoprotein(a) level s and HDL subfraction profiles. Design: Thirty nine postmenopausal wom en were treated with tibolone (Livial) 2.5 mg/day for 6 months and fas ting serum lipoprotein levels were estimated at 0, 2, 4 and 6 months. Results. Lipoprotein(rt) levels were reduced significantly over the 6 months from a median level of 245 (range <60-780) mg/l to 152 (range < 60-530) mg/l, a reduction of 39% in the median level. A decrease was observed in approximately two thirds of the women. Reductions were not ed in all 6 subjects whose pretreatment levels were high, although con centrations remained at a level associated with increased risk in all but one. There were significant decreases in triglycerides and VLDL ch olesterol and no significant change in LDL cholesterol. There was a si gnificant reduction of 18% in HDL cholesterol and a 26% reduction in t he HDL(2):HDL(3) ratio. Conclusion: The reduction in lipoprotein(a) le vels may have a beneficial effect on cardiovascular risk, which could go some way towards balancing the potentially adverse effect on the ca rdiovascular system caused by the reduction in HDL cholesterol.