Two-year follow-up of changes in clinical chemistry in Singaporean Norplant® acceptors: Metabolic changes

Abstract

In this longitudinal study involving 100 Singaporean acceptors, the effects of Norplant® on metabolic function was evaluated. With respect to liver function, the results at the end of two years still indicate the presence of possible hepatocellular dysfunction. Despite a 4.5% decrease in serum bilirubin during the second year, the mean serum bilirubin still remained significantly raised (p < 0.001). Furthermore there was a significant fall in total proteins and globulins during the period under review (p < 0.001). However mean levels of all three parameters remained within the normal clinical range. As regards lipid metabolism, the total triglycerides and total cholesterol still remained significantly decreased at the end of two years (p < 0.001). The LDL-cholesterol, which was significantly decreased at the end of one year, increased by 2.2% during the second year. However, this rise in LDL-cholesterol was not significant and was still below the preinsertion level. The HDL-cholesterol levels returned to their preinsertion levels after a significant increase in the first year. The HDL-cholesterol/Total cholesterol - HDL-cholesterol ratio returned to its preinsertion value at the end of two years while the LDL-cholesterol/HDL-cholesterol ratio was still significantly lower than the preinsertion ratio (p < 0.05). As we have not incorporated a simultaneous non-steroid treated control group, the observed changes in lipoprotein lipids could be attributed to extraneous factors such as diet, exercise or other environmental changes. Nevertheless, the findings at the end of two years, though speculative, still indicate Norplant® use to be non-contributory to cardiovascular risk and indeed it may be a protective factor against such risks in this population. The use of Norplant® was not associated with any significant effect on glucose tolerance after two years of use.