August 28, 2001
Diagnosis and Symptoms
Question from Omaha, Nebraska, USA:
I am a 6 foot 1 inch male who began having most of the symptoms of diabetes nine months ago when I weighed around 208 pounds. After two months, I finely woke up, realized something was wrong, and contacted a doctor for a physical. It took awhile to get the physical, and by that time saw the doctor, I had changed my diet and started exercising. Most importantly, all of the symptoms had disappeared.
The doctor did a fasting glucose which was 137 mg/dl [7.6 mmol/L] (which I am sure was way down from two weeks prior to the appointment). I continued to diet and got my fasting levels down to the 90s mg/dl [5mmol/L] and mostly normal ranges two hours after meals, but I began to worry because I was still losing weight even though I was attempting to eat more (but healthier) food.
The doctor did an oral glucose tolerance test, and what t stuck me as odd was that he used a 100 gram load. The results were: pre-load — 101 mg/dl [5.6 mmol/L]; one-hour — 287 mg/dl [15.9 mmol/L]; two-hours — 178 mg/dl [9.9 mmol/L]; and three-hours — 52 mg/dl [2.9 mmol/L]. I have three questions:
Is the 100 gram load right? I have looked and it appears 75 grams is standard.
How do you analyze these results?
My glucose levels were great for a month after the test (fasting tests in the low to mid 70s mg/dl [3.9 mmol/L]), but have recently gone slightly back up. Could the test have produced a temporary improvement in my ability to produce or use insulin?
I have finally leveled off and my weight has been steady at around 164 pounds for the past month, but I find it a battle to put any weight I lose back on. I assure you I am eating plenty of calories (2500) a day and am still a little high on my fat intake, although the saturated fats are way down and the useless carbs are almost nonexistent.
Answer:
You are correct. The routine oral glucose tolerance test (OGTT) uses a 75 gram oral glucose load. The 100 gram load is usually used for screening for gestational diabetes.
The results are abnormal if two values are above 200 mg/dl [11.1 mmol/L]. The most important one is at two hours. The diagnostic criteria say that a two-hour glucose greater 200 mg/dl [11.1 mmol/L] during an OGTT is consistent with diabetes. That being said, the 100 gram load does not invalidate your results which are not consistent with type�2 diabetes. Rather, you have what appears to be impaired glucose tolerance. A third of people with this go on to develop diabetes. Recently, the Diabetes Prevention Program demonstrated that intensive lifestyle modification with diet and exercise can reduce your risk of developing diabetes.
I would recommend you see your physician regarding your results and a plan for risk modification. It already sounds like you are changing your diet dramatically. Please follow-up with your physician because your situation requires monitoring.
JTL
