DEAR DR. DONOHUE: What’s the difference between diabetes 1 and 2? Doesn’t diabetes mean high blood sugar? Do 1 and 2 both have high blood sugar? I want to know about diabetes because my sister, age 49, has just come down with diabetes 2. What are my chances of getting it? – K.K.

ANSWER: All diabetes varieties feature high blood sugar. Differentiating them into types (there are more than two types) is important because the various types have different causes, different treatments and different implications.

Type 1 diabetes used to be called juvenile diabetes or insulin-dependent diabetes. It most often comes on in young life – but not always, so the “juvenile” designation is not appropriate. It almost always demands treatment with insulin, so the insulin-dependent tag is not entirely incorrect, but it can be misleading. Type 1 diabetes is the result of an autoimmune attack on the pancreas cells that make insulin. Without insulin, blood sugar rises. In North America there are around half a million type 1 diabetics, with close to 30,000 new cases added yearly.

Type 2 diabetes, the old “adult-onset” diabetes, can come on during childhood, so “adult” is erroneous. It’s the kind of diabetes that results from body cells being unable to respond to insulin. People with this kind of diabetes usually make enough insulin, but their insulin doesn’t work. Blood sugar rises. Oral medicines, along with diet, can often normalize blood sugar for these people. However, many type 2 diabetics reach a point where they must resort to insulin injections. More than 15 million North Americans have type 2 diabetes, and more than 625,000 come down with it each year.

Genes play a role in both types, but the genetic influence is greater in type 2 than in type 1. If one parent has type 2 diabetes, the chances that his or her child will have it range from 1 in 7 to 1 in 13. That’s roughly your extra risk of coming down with diabetes, because your sister has type 2. Exercising and staying slim lower those risks.

The diabetes booklet describes the treatment and prognosis for both kinds of diabetes. To obtain a copy, write: Dr. Donohue – No. 402, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.50 U.S./$6.50 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: Eating had been giving me great pain in my left cheek for about five weeks. I saw an ENT doctor, who discovered I had a stone in my salivary gland on that side. He’s going to try to remove it in his office. If he can’t, what lies in store for me? – G.J.

ANSWER: Everyone has heard of kidney and gallbladder stones. Few have heard of salivary gland stones, but they happen. Sometimes saliva becomes thick and plugs the duct draining the salivary gland. As the saliva dries in the duct, calcium deposits there, and soon a stone forms. It can be a tiny speck or as large as a small olive pit.

Eating stimulates saliva production. If saliva cannot exit the gland through the blocked duct, the gland swells and hurts.

A doctor can sometimes remove the stone with a probe, and sometimes that can be done in the office. If the doctor fails to retrieve the stone or if the stone is in a location inaccessible to a probe, then the doctor might have to surgically open the duct. Sound waves have been used to fragment salivary stones and allow them to pass out of the duct and the gland.

DEAR DR. DONOHUE: Please describe a “no-scalpel” vasectomy. I am interested in having the procedure done. My wife and I do not want any more children. – H.F.

ANSWER: The vas is the duct through which sperm travel on their way out of the testicle. In a no-scalpel vasectomy, the doctor, with a forceps, grasps the vas from the scrotal skin surface. Then he or she makes a tiny hole in the skin and through the hole punctures the vas. The hole is so small it heals on its own. The procedure takes about 10 minutes.

The skin, of course, is deadened prior to this mini-operation.

DEAR DR. DONOHUE: What’s an acceptable sed rate? – N.J.

ANSWER: The sed rate – short for sedimentation rate – is a simple test that detects body inflammation, but it doesn’t tell where the inflammation is. Blood is put in a calibrated tube, and the distance that the red blood cells drop from the top of the tube in one hour’s time is the sed rate.

The normal sed rate for women is 0 to 25 mm (higher for those over 50), and for men, 0 to 17 (again, higher for those over 50.)

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475.