MARKED HYPERINSULINEMIA IN POSTMENOPAUSAL, HEALTHY INDIAN (ASIAN) WOMEN

The effect of the menopause on insulin metabolism has not received spe cific attention in populations prone to non-insulin-dependent (Type 2) diabetes mellitus (NIDDM). Insignificant or slight alterations in ins ulin levels have been reported in postmenopausal women of mainly Europ ean ancestry. We thus report on the results of a cross-sectional study on the correlates of fasting insulin levels in 177 healthy, Indian nu rses aged between 25 and 55 years. Fasting insulin concentration was m arkedly higher in the 75 postmenopausal subjects (23.9 mUl(-1)) than i n the 102 premenopausal women (11.7 mUl(-1) (p < 0.0001). Forty-three (57%) of the postmenopausal subjects had insulin values more than 20 m Ul(-1) (the upper normal limit). Stepwise regression analysis on the e ntire group revealed menopause (p<0.0001), waist:hip ratio (p=0.0001), apolipoprotein E genotype (p=0.002), and the testosterone:sex hormone binding globulin ratio (p=0.0002) as statistically significant, indep endent predictors of log insulin levels. Age did not account for the d ifference between premenopausal and postmenopausal subjects. The apoli poprotein E genotype emerged as a significant correlate of insulin lev els, only in postmenopausal women: epsilon 3/3, 26.3 mUl(-1); epsilon 3/4, 51.8 mUl(-1) (p = 0.0007). Hyperinsulinaemic postmenopausal subje cts had higher fasting glucose levels than normoinsulinemic nurses (p = 0.03), but glycosylated haemoglobin and fructosamine values were all within the normal range. Thus fasting hyperinsulinaemia was marked an d common among a group of healthy, postmenopausal Indian nurses below the age of 55 years, suggesting that the menopausal transition may per mit or provoke insulin resistance in this susceptible population.