Israeli researchers who followed up on more than 13,000 "healthy" career soldiers for up to 12 years have found that fasting levels of blood sugar considered on the high end of "normal" could predict the development of type II diabetes.
The researchers, from Ben-Gurion University of the Negev in Beersheba and the Israel Defense Forces Medical Corps for the Israel Diabetes Research Group, suggest in the October 6 issue of The New England Journal of Medicine that "high-normal" blood glucose levels of up to 100 mg/dl after a 12-hour fast could be a warning sign that patients will develop diabetes as they get older. Until now, blood glucose of 126 mg/dl or more has been enough to diagnose diabetes, whereas values of up to 100 are considered "normal."
Their article is accompanied by a special editorial on the subject by Dr. Ronald Arky of Harvard Medical School who said there is no reason to believe that the results are relevant only to men, and that healthy young people of both sexes should be counselled on weight, lifestyle and blood lipid profiles. Arky concluded that when healthy patients ask their physician, "Doctor, is my sugar normal," the answer should be, "Yes, your glucose level is normal, but let's do something about that weight and your sedentary lifestyle."
Diabetes is becoming a worldwide epidemic, attributed to genetic predisposition coupled with increasing rates of obesity, sedentary lifestyle and nutritional factors. Although the disease used to be diagnosed almost exclusively among people over the age of 50, it is now increasingly observed in people in their 20s, 30s and 40s.
Prof. Itamar Raz, head of the diabetes center at Hadassah University Medical Center and past chairman of the Israel Diabetes Association, commented that the study, "which is incredibly important," shows that one should aim for no more than 80 mg/dl, but the borderline is not uniform for all people; risks for diabetes and cardiovascular disease also depend on other factors as well.
Researchers Dr. Assaf Rudich (of BGU's nutrition center and department of clinical biochemistry), Dr. Amir Tirosh (an IDF physician and BGU medical school graduate) and Dr. Iris Shai (of BGU's epidemiology department) decided to find out whether blood sugar levels even within the normal range can help in identifying young men at risk for type II diabetes. Along with the other members of the team, they analyzed data of the IDF Staff Periodic Examination Center on 13,163 men aged 26 to 45 (mean age 32) with fasting blood glucose of below 100 mg/dl and followed them for six years.
During this period, 208 new cases of diabetes were diagnosed. Men with higher levels (95-99 mg/dl) of "normal" blood glucose were found to be about three times more likely to become diabetic than men with a blood glucose of 81 mg/dl or less. These cutoff points predicted diabetes independently of the effects of family history of the disease, body weight and levels of blood lipids (triglycerides), which are known risk factors for diabetes. When risk factors were combined, the chances of becoming diabetic increased dramatically: Obese men who also had a blood glucose level of 91 to 99 mg/dl were more than eight times more likely to become diabetic compared to non-obese men with blood glucose of 86 mg/dl or less.
The researchers concluded that a "normal" glucose level (a level not associated with increased diabetes risk) should be defined in a more "individualized" manner, having different values depending on a person's family history, weight and triglycerides. In addition, they said, what they learned from the study will help in identifying young, apparently healthy adults who are at risk of becoming diabetic, and make it possible to initiate preventive interventions, such as exercise and diet changes, that could prevent the onset of diabetes.