To take HRT or not to take HRT – that is the controversial question. Some research has shown that hormone replacement therapy (HRT) can have health-supporting benefits; and then again, some has shown that it may have some significant risks as well. At HSI, we’ve tried to cover both sides of the issue so that you can make the best decision for your situation.
Just this week, I came across a new study that throws its weight firmly into HRT’s “Con” column. Researchers at the University of Maryland School of Medicine found that HRT increases insulin-resistance – and may increase your risk of developing Type II diabetes.
Does HRT help – or hurt?
Insulin resistance, or insulin sensitivity, is a serious condition that affects millions of people around the world. It occurs when the normal amount of insulin released by the pancreas cannot effectively process the glucose in the bloodstream. When the body senses that there is still glucose in the blood, it secretes more insulin, leading to higher blood insulin levels. This inefficiency can also lead to high blood glucose levels – another way of describing Type II diabetes.
Previous studies had shown conflicting results on HRT’s effects on insulin resistance. Some suggested that HRT may actually help prevent the condition, by reducing the weight gain that often accompanies menopause. (Overweight and obesity are known risk factors for insulin resistance and Type II diabetes.) Specifically, some research has suggested that HRT can help prevent the accumulation of excess fat in the abdominal area, which is considered the most dangerous place to carry excess body weight.
But in this new study, HRT had no impact on overall body weight or fat distribution. And in one-on-one comparisons of HRT users and non-HRT users, hormone replacement therapy still demonstrated a significant negative effect on insulin resistance.
HRT had no impact on body composition
Here are the details: The researchers recruited 28 Caucasian women between the ages of 50 and 70. All had a body mass index (BMI) of 25 or above, which classified them as overweight or obese. Also, all of the women were sedentary, meaning they got less than 20 minutes of aerobic exercise twice a week, and all were at least one year post menopause.
The women were divided up by their current HRT status. A total of 14 of them had been taking HRT for at least three years; six taking oral estrogen and eight taking oral estrogen plus progesterone. The other 14 were not taking any form of HRT. Each of the women in the HRT group was matched with a non-HRT user; the pairs were matched for age, weight, and BMI.
Each participant’s fitness level and body composition was assessed at baseline. Body composition was measured by BMI and waist-to-hip ratio, as well as through imaging procedures. The imaging procedures allowed the researchers to quantify relative proportions of adipose tissue (fat) in different areas of the body. They found no significant differences in body composition between women who took HRT and those who did not.
but it had plenty of impact on insulin resistance
Then the researchers set out to assess the women’s insulin sensitivity. Their response to insulin and glucose was measured by the hyperinsulinemic-euglycemic clamp method; basically, baseline glucose and insulin levels were assessed by three blood samples taken at 10 minutes intervals, then insulin was administered intravenously for three hours. The results of blood samples taken every five minutes during the last 30 minutes of the test were averaged to arrive at mean values for glucose utilization and insulin sensitivity.
All of the women had similar plasma glucose and insulin levels after an overnight fast. But during the “clamp” test, the differences became obvious. Women taking HRT had significantly lower glucose utilization scores than non-users (26 to 31 percent less). The assessment of insulin sensitivity (expressed in the amount of glucose metabolized per unit of plasma insulin) produced similar results; women on HRT showed significantly less insulin sensitivity than non-users (28 to 36 percent less). While women taking a combination of estrogen and progesterone recorded slightly better results than women taking estrogen alone, their results were also significantly worse than non-users.
More research is needed to determine if HRT has similar effects on other women, such as those who are active and thin. But this study reveals an important point that women should consider when weighing the risks and benefits of HRT – particularly in light of skyrocketing Type II diabetes rates around the world. Please pass this on to others you know who take HRT or who are weighing their options. Women everywhere need to understand all the potential benefits and risk of any therapy before they make a decision.
Source:
Diabetes Care 25:127-133, 2002
