I have been having many common symptoms of diabetes, including frequent urination and increased thirst. I have also gained an enormous amount of weight in the past 24 months. Diabetes is rampant in my family. I went to my family doctor who tested my blood sugar and thyroid (among other things) but all came back normal. Is there anything else that has similar symptoms that maybe we are missing?
There are a number of issues raised by your diabetes question. I think you are right to be concerned about diabetes in view of your family history, weight gain, and frequent urination. If both your parents have non-insulin dependent diabetes mellitus (NIDDM, also called Type II diabetes), your chances of developing the same condition are 50 percent or greater, especially if you are sedentary and overweight.
The finding of a normal blood sugar by your doctor may rule out diabetes, but like many things, it may not be quite that simple. The time of day and relationship to your food intake can be important. Someone with NIDDM can have a normal fasting blood sugar, especially early on. For the blood sugar to be most accurate, it should be done two hours after you have drunk a measured amount (75 g) of a sugar drink. This is an oral glucose tolerance test (OGTT). A blood sugar over 200mg/dl during an OGTT is diagnostic of diabetes according to the most recent criteria. A new intermediate diagnosis, impaired glucose tolerance, is diagnosed if the two hour level is between 140mg/dl and 200 mg/dl. A glycohemoglobin test can also show if diabetes is present even when the blood sugar is sometimes normal.
Did your doctor check for sugar in your urine? Although this is usually much less accurate than a blood test in detecting diabetes, the urine must contain sugar in a diabetic who is urinating frequently because of the disease . It is the presence of the sugar in the urine that causes more fluid to also be excreted. This is called an osmotic diuresis; the osmotic pressure of the sugar is essential to create the extra urine flow. Therefore, testing your urine at a time when you are having excessive urination must reveal sugar, if NIDDM is the cause.
There are other causes of frequent urination and thirst. Probably most common is simply being in the habit of drinking a lot of fluids. Some people consciously or unconsciously drink more water than the rest of us, and therefore excrete more as urine. Anxiety may underlie this habit in some. There is also a disease, diabetes insipidus (no relationship to diabetes mellitus), which causes a person to excrete very dilute urine in large amounts. This condition can stem from a kidney or pituitary problem. Distinguishing the kidney type from the pituitary type, and both from simply drinking too much fluid out of habit can be tricky, and may involve withholding fluids for a while while testing the blood and urine. This test should be done under a doctor’s supervision.
If your doctor has really ruled out diabetes, either with an appropriately-timed blood sugar or a glycohemoglobin test, then your frequent urination is from something else, probably a high fluid intake, since diabetes insipidus is rare. Decide if the excessive urination is bothering your life. If it’s only a mild annoyance, and you have no other problems that might point to a pituitary tumor, then live with it. If it’s a real bother, then you may need to proceed with more tests, possibly including the water deprivation test I mentioned.
Regardless of what your tests show now, you probably are a sitting duck to develop NIDDM sometime. Now is the time to change your lifestyle in the hope of preventing it! Weight loss, increased regular exercise, and a diet low in sugars will be essential. Our metabolism was set a million years ago by ancestors who had to run down, trap, or pick everything they ate. They weren’t fat, and they exercised a lot. I know in our modern age it isn’t easy, but it is the only way to prevent NIDDM if you are genetically susceptible.