A Massive Long Term Study Sheds More Light on Truly Normal Fasting Glucose Values

A study brought to my attention by this week's edition of Diabetes in Control newsletter makes it very clear that for people with symptoms of the metabolic syndrome a fasting glucose blood sugar test result of 95 mg/dl or higher should impel their physicians to order a glucose tolerance test.

What the study found in brief is this: Over a 9 year period, within a group of 46,578 members of Kaiser Permanente Northwest, 10% of those who started out with fasting plasma glucose values of 95 to 100 mg/dl ended up diagnosed as diabetic based on a fasting plasma glucose test result greater than 125 mg/dl.

In contrast, only about 3% of those with fasting blood sugars below either 85 mg/dl or 89 mg/dl were diagnosed with diabetes.

Within the group which became diabetic, other factors which increased the likelihood of becoming diabetic, in order of impact, were diagnosed cardiovascular disease, high blood pressure, smoking, high triglycerides, and elevated BMI.

Significantly, there was NO significant correlation between the levels of LDL or HDL cholesterol and the likelihood of becoming diabetic. ONLY the trigyclerides--which are a good reflection of the blood sugar level after meals, predicted oncoming diabetes.

The complete text of the study is free, which is a nice change. You can read it here:

Normal Fasting Plasma Glucose and Risk of Type 2 Diabetes Diagnosis.
Gregory A. Nichols, Ph.D. et. a.. The American Journal of Medicine. Vol 121,issue 6, 519-524 (June 2008)

Note in particular this graph: Kaplan-Meier plot of cumulative diabetes incidence by category of normal fasting plasma glucose.

In their conclusions the authors point out that the lack of glucose tolerance test data for this population limited the value of the study and suggest that those with fasting glucose values of 95 mg/dl and higher most probably would have tested at the prediabetic level on a glucose tolerance test. They also point out that "Among those who developed diabetes by our criteria, however, the mean hemoglobin A1c at diagnosis was more than 7%, a level that strongly suggests that abnormal glucose metabolism has been maintained for several months."

My guess is that the over 7% A1cs suggest that the glucose metabolism had been abnormal for several years--probably beginning when that fasting glucose went over 94 mg/dl.

The group in this study whose fasting blood glucose was between 90 and 94 mg/dl had an incidence of diabetes that was about 5%.

What does this mean for you if your fasting glucose is in the 90s?

It means you need to get yourself a meter and to start testing your post-meal blood sugars, one and two hours after eating, to see how high your blood sugar is rising. You don't have to do this very often. Once or twice a year is all you need to do assuming you do not see post-meal blood sugars over 125 mg/dl which seems to be the peak most truly normal people attain, very briefly, before their blood sugar drops back to their fasting level.

If you see your blood sugar rising over 140 mg/dl after meals, take it as a sign that you are very likely to have prediabetes and start taking steps to improve your blood sugar health now, when it is still relatively easy to reverse any early diabetic changes in your body and preserve your beta cells from harm.

If your fasting blood sugar is in the 90s here are some steps you can take to improve your blood sugar health.

1. Cut the carbs. Carbs are what raise blood sugar and you are probably eating a lot of junk carbs that are stressing your body and pushing you towards developing diabetes. Try cutting out the following: All non-diet sodas, fries, white bread, breakfast cereals containing more than 10 grams of carbs per serving (most people eat two or three "servings" every time they fill a bowl with cereal, large muffins (6-8 oz), large servings of pasta, etc. Cutting carbs will lower your triglycerides, the only part of your cholesterol linked with developing diabetes.

2. Exercise. If you aren't the gym rat kind, start taking a 40 minute walk four or five times a week. That has been shown to be enough to make significant improvements in your fitness without causing injury.

3. Check your meds. Many commonly prescribed medications have a side effect of causing "hyperglycemia" i.e. high blood sugar. Read the official Prescribing Information for all medications you are taking and see which ones might be contributing to your rising blood sugars. Some drugs known to raise blood sugar are HCTZ, SSRI antidepressants, Zyprexa, prednisone and other corticosteroids. There are others. If you are taking a medication that raises blood sugar, talk to your doctor about whether there are alternatives which won't put you at risk of kidney failure, blindness, increasing heart disease, and amputation--which are what can happen to you over time if you allow your blood sugar to rise unchecked.