Effects of HRT on Carbohydrate Metabolism in Women With Diabetes

There is a degree of reluctance among health care professionals to prescribe HRT to women with diabetes. A community-based survey in London found that diabetic postmenopausal women were less than half as likely as the general population to be prescribed HRT (137). Doctors and health care professionals perceive HRT as detrimental for diabetic women because of fear about glycemic control as is also the case with the oral contraceptive pill (138). Yet there is no evidence that HRT results in deterioration of glycemic control in women with diabetes.

In general, the available data indicate that HRT either improves or has neutral effects on carbohydrate metabolism in women with diabetes depending on the estrogen and/or progestogen formulation used (Table 2).

Oral estradiol has been shown to improve glucose metabolism and insulin sensitivity in diabetic women (132,139), whereas transdermal estradiol was found not to affect glycemic control (140). The addition of norethisterone does not appear to adversely affect glycemic control, although it may reduce any benefit seen with oral 17^-estradiol alone. In women with IGT, Luotola and associates (141) reported that natural estrogen/progestogen substitution improved insulin sensitivity, as shown by decreased glucose levels on oral glucose tolerance test. In postmenopausal women with hyperinsulinemia, transdermal estradiol also decreased plasma insulin and improved insulin sensitivity with further improvement by the addition of dydrogesterone (142). Regarding the effect of CEE in women with diabetes, limited work has shown either neutral effects on fasting blood glucose or insulin levels, or a reduction in HbA1c which was, however, attenuated when MPA was added to the regimen (143,144). The mechanism of estrogen action on glucose metabolism is not clearly known. Brussaard and associates (139) showed that ERT enhanced insulin suppression of hepatic glucose production in postmenopausal women with diabetes. Interestingly, this suppression was enhanced only in women with normal triglyceride levels and not in those with hyperglyceridemia. On the other hand,

Table 2

Effects of Hormone Replacement Therapy on Carbohydrate Metabolism

Effects of Estrogens

-Estradiol improves insulin sensitivity -Low-dose cEE does not affect insulin sensitivity -High-dose cEE impairs glucose tolerance

Effects of progestogens

-MPA impairs glucose tolerance

-Norethisterone has neutral effects on insulin sensitivity

-Dydrogesterone improves insulin sensitivity

CEE, conjugated equine estrogen; MPA, medroxyprogesterone acetate.

Samaras and associates (144) suggested that estrogen effects on body composition and lipid metabolism may explain improvements in glycemic control; partitioning fatty acids away from the central abdominal depot to the gluteofemoral region reduces circulating fatty acid effects on insulin action (145).

It is important also to note that in women with diabetes, the changes that accompany menopause may further deteriorate glycemic control and HRT may attenuate this effect. Indeed, in the studies conducted by Brussaard and associates (139) and Samaras and associates (144), HbAlc detrimentally increased in the placebo groups in postmenopausal women with type 2 diabetes, whereas in the same reports, and in others, HbAlc was significantly reduced with ERT (146).

It appears that regarding glycemic control, low-dose HRT can be used in women with type 2 diabetes without undue concern. The recent North American Menopause Society (NAMS) consensus paper (147) advised that if oral ERT is used in women with type 2 diabetes, then only low-dose formulations should be prescribed. Beneficial effects on insulin sensitivity may be observed with HRT, although more work is needed in the area.

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Responses

  • Calleigh
    Does hrt decrease carbohydrate tolerance?
    6 years ago

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