[Long-term effects of low-dose combined norethisterone and combined 18-metayl-norethisterone on lipid metabolism in healthy women].
OBJECTIVE
To assess the long-term effects of combined oral contraceptive pills use on the mean of serum TG, TC, HDL-C, LDL-C, ApoA1, ApoB and Lp(a).


METHODS
The study was carried out in 446 women grouped as combined norethisterone containing ethinylestradiol (EE) 35 micrograms and norethisterone 625 micrograms; combined 18-metayl-norethisterone (norgestrel) containing EE 30 micrograms and 18-metayl-norethisterone 300 micrograms for using 5-25 years, and control subjects wearing IUD for the corresponding period. The three groups were similar in age, body mass index (BMI), continued period of contraceptives use and income.


RESULTS
The data showed that changes of varying degree of lipid and lipoprotein parameters were obvious in women of long-term taking low-dose combined norethisterone and norgestrel, compared with the control. The mean of TG, HDL-C, ApoA1 were significantly increased simultaneously (P < 0.05, P < 0.01), indicated multiple effects of two low-dose Chinese COCs on lipid lipoprotein parameters. In addition, A significant increase (P < 0.05) in Lp(a), an independent risk factor for cardiovascular disease, was found in norgestrel group. Further more, the results of stratified analysis to duration of contraceptives use showed that the mean of TC, LDL-C, in the combined norethisterone use less than 15 years, after the adjusting for age, were significantly lower (P < 0.05, P < 0.01) and the ratio of LDL-C/HDL-C was improved (P < 0.05), compared with the Norgestrel; at the same time, the mean of ApoA1 was markedly higher (P < 0.05) in combined norethisterone; the ratio of ApoA1/ApoB (1.87 +/- 0.58) in the combined norethisterone group was superior to the ratio value (1.68 +/- 0.55) in norgestrel group.


CONCLUSIONS
These beneficial effects on lipid metabolism have been considered indicators of potential cardiovascular protective effect of the combined norethisterone for taking pill less than 15 years, but these protective effects would be reduced with adverse change in lipid and lipoprotein parameters for taking combined norethisterone more than 15 years. In contrast, the mean of TC, LDL-C, two known risk factors for cardiovascular system, in the norgestrel use less than 15 years, after the adjusting for age, were significantly increased (P < 0.05, P < 0.01), and adverse changes in the TC/HDL-C ratio (P < 0.05) and ASI value, compared with the combined norethisterone; Lp(a) level was markedly higher in the norgestrel group than that in the control group (P < 0.05). These adverse effects on lipid metabolism have been considered indicators of potential cardiovascular harmful effect of low-dose norgestrel.
Li
Y
Y
Jiangsu Family Planning Research Institute, Nanjing 210029, China.
Dong
G
G
Wu
Y
Y
D000328:Adult; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008075:Lipoproteins, HDL / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood; D009640:Norethindrone / Q000008:administration & dosage / Q000494:pharmacology*; D009644:Norgestrel / Q000008:administration & dosage / Q000494:pharmacology*; D045167:Progesterone Congeners / Q000008:administration & dosage / Q000494:pharmacology*
D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D045167:Progesterone Congeners; D009644:Norgestrel; D009640:Norethindrone