A Research Extravaganza
Once again, Diabetes Health has read through more than 2,500 abstracts of research presented at the American Diabetes Association's annual Scientific Sessions and selected a few of the more interesting ones to pass along to you as part of our annual "Research Extravaganza" feature.
If you want to read the entire abstract, go to the ADA's Web site at www.diabetes.org. Click on "For Health Care Professionals," then on "Review the Recent Scientific Sessions." Finally, click on "Interactive Scheduler & Online Abstract Search." You will be asked to give your e-mail address and to create a password for yourself. Once you set that up, you can look up any abstract you want, including the ones we've cited in this issue.
Sugar and Spice—and More Insulin-Resistant
At the age of 5, girls are 27 percent more insulin-resistant than boys, according to results from the EarlyBird Study.
Researchers in the United Kingdom gathered data on 307 children with an average age of 4.9 years. Body mass index (BMI), subcutaneous fat by skinfolds (SF), waist circumference, physical activity and insulin resistance were measured at six- and 12-month intervals.
While waist circumference did not differ in the two groups, SF was 23 percent higher in girls and had "the greatest effect on gender difference in [insulin resistance]," the researchers report. BMI was 3 percent higher in girls. Although boys were more physically active than girls, the difference had "minimal impact" on insulin resistance.
Girls also had significantly higher triglycerides and lower HDL (good) cholesterol than boys.
Still in Good Control After All These Years
Thirty-nine participants from the 1982 Oslo Study in Norway, all of whom had had diabetes for 30 years, were re-examined after 18 years using electrophysiological tests. All participants had used multiple daily injections or insulin pumps for 14 to 18 years.
The researchers also discovered that an average A1C higher than 9% over the past 18 years led to a higher incidence of neuropathy.
Insulin Therapy Decreases Artery Stiffness
In addition to lowering blood-glucose levels, insulin therapy also lessens stiffness in the large arteries, say researchers from Helsinki, Finland, who compared the degree of artery stiffness in subjects with type 2 diabetes to those without diabetes. Before beginning insulin therapy, glucose metabolism was 33 percent less in the subjects with diabetes and basal arterial stiffness was significantly higher. After six months of insulin therapy, the type 2 subjects' insulin sensitivity was increased by 31 percent, and their arterial stiffness was comparable to that of subjects who did not have diabetes.
Controversial Surgery Improves Insulin Action in Skeletal Muscle
Gastric bypass surgery not only induces weight loss but also improves insulin action in the skeletal muscle, say researchers from San Francisco, California, and Greenville, North Carolina.
Ten people who underwent gastric bypass surgery were observed both before their surgery and for the following one year. Participants lost an average of 106 pounds, while average body mass index decreased from 47 to 30.4.
The researchers report that insulin action in skeletal muscles improved with the weight loss, "due in part to an increased capacity for insulin receptor signaling in muscle resulting largely from increased insulin receptor expression."
Chest Pain Associated With Hypoglycemia
People with type 2 diabetes and known coronary artery disease are more likely to experience chest pain when their blood-glucose levels are too low—particularly if blood glucose changes more than 100 mg/dl over 60 minutes.
Researchers from New Orleans, Louisiana, used simultaneous continuous glucose monitoring systems and cardiac holter monitoring in addition to having subjects record chest pains and hypoglycemic events. Hypoglycemia was considered to be a blood-glucose level of less than 70 mg/dl or the presence of symptoms.
Get Moving! A Lack of Exercise May Be to Blame for Japan's Diabetes Epidemic
Which contributes more to type 2 diabetes—increased fat intake or decreased physical activity? For Japanese men, the answer appears to be decreased physical activity.
Japan has recorded a 40- to 50-fold increase in type 2 diabetes over the past 50 years. In a study that sought to determine whether a Westernized diet or a decrease in exercise contributed more to this rise, Japanese researchers determined that a lack of exercise was the main contributor to an accumulation of abdominal fat and to type 2 diabetes among men.
From the Heart—A Potential New Source of Islets
Recent advances in islet transplantation have been tempered by a severe islet shortage, which is caused in part by a lack of cadaver pancreas donors. However, according to researchers in Philadelphia, Pennsylvania, "islets taken from a non-heart-beating donor can provide a source of islets suitable for clinical transplantation."
Between February 2000 and January 2002, the researchers isolated islets from 112 human pancreases, including 10 from non-heart-beating donors. Islets taken from these donors were found to "perform equally well as those from brain-dead donors."
Resisting Control—Insulin Resistance, Not Insulin Production, Is Key to Hyperglycemia
Pre-meal high blood-glucose levels are most strongly influenced by insulin resistance in type 2 diabetes, say researchers in Israel who studied the role of insulin secretion versus insulin resistance in 473 subjects. Because insulin resistance has been present for some time before type 2 diabetes is diagnosed, beta cells are already functioning at their peak ability and cannot secrete any more insulin, the researchers conclude.
Transplants Improve Lives
People who have simultaneous kidney-pancreas transplants generally experience an improved quality of life, especially in terms of mental health, physical activities and general health perception, report researchers in Pittsburgh, Pennsylvania, and the United Kingdom.
Overall, there is little change in the financial status of these individuals, although some see an increase in medical expenses, while others experience a decrease. Their use of medications is considerably altered, with researchers reporting a vast decrease in the use of calcium channel blockers and no use of ACE inhibitors following transplants.
China Syndrome—Insulin Resistance and Heart Problems Linked
Insulin resistance contributes to cardiovascular disease—even in people who do not have diabetes. Researchers in China studied 10 obese people and 10 lean people to evaluate the effects of insulin resistance on arteries. Although none of the subjects had diabetes, those who were obese showed insulin resistance and markers for cardiovascular disease, despite having normal levels of lipids, blood pressure and blood glucose. Researchers observed that the degree of insulin resistance increased with added weight.
Just Say ‘No'—Assisting Others Can Hinder Self-Care
African-American women with type 2 diabetes who have too many people asking them for assistance, who have difficulty saying "no" to the requests, and who place the family's needs first are less likely to take proper care of their diabetes when it comes to diet and exercise.
Researchers in Chapel Hill, North Carolina, found that African-American women who had more people seeking help from them were less likely to follow a proper diet. Those who had difficulty refusing requests from others followed their diet for fewer days.
Where It's At—Fatty Liver Equals Insulin Resistance
Insulin resistance depends on where the fat is located—not on overall fat mass—say researchers from Helsinki, Finland, who compared insulin resistance in obese women with and without high levels of liver fat. The 21 women studied had previously been diagnosed with gestational diabetes.
Women with increased amounts of liver fat also had higher fasting blood-glucose levels and higher triglycerides than women with low liver fat content. Although numbers did decrease, insulin resistance and triglycerides remained significantly higher in those with a greater liver fat content, even after similar weight loss in both groups.
Girls With Type 1 Diabetes Have Later First Menstruation
The age at which menarche (the beginning of menstrual function) occurs is later in girls who have type 1 diabetes.
In a pilot study conducted by researchers in the United Kingdom, 60 girls with type 1 diabetes were compared to 76 girls without diabetes. Among the latter group, 28 percent reported having their first menstruation before the age of 12, compared to 13.3 percent of girls with type 1.
Pregnant Women With Type 1 Diabetes Can Have Children With Impaired Glucose Tolerance
In a French study, nearly half of the children born to women who had type 1 diabetes during pregnancy had impaired glucose tolerance, an effect that was not present in the children of men with type 1 diabetes. None of the children studied had markers for type 1 diabetes.
The 45 percent of the children who showed impaired glucose tolerance had insufficient insulin secretion but were not insulin-resistant. The findings led researchers to speculate that the environment inside the uterus of a woman with type 1 diabetes could predispose her children to abnormalities in insulin secretion. However, the cause is unknown, say the researchers, who compared 11 offspring of women with type 1 diabetes during pregnancy to 14 offspring of men with type 1 diabetes born after the diagnosis of diabetes in their parents.
Progestin Could Cause Insulin Resistance
Implantable and injectable progestin-only contraceptives cause insulin resistance and are associated with an increased risk of type 2 diabetes, say researchers from Atlanta, Georgia, who studied 30 years of publications relating Depo-Provera and Norplant to insulin-glucose metabolism.
Some studies done on non-obese women primarily in developing countries found significant elevations of insulin following an oral glucose tolerance test. Researchers say women in the United States who receive the contraceptives may start out with more insulin resistance because of greater weight, lifestyle factors and family or obstetrical histories.
Educating the Mind and Body
Blood-glucose control may be improved if psychological factors are integrated into diabetes education rather than presented as a separate intervention, according to researchers in Boston, Massachusetts.
Among a group of subjects who received diabetes education using an integrated approach, A1C results were only slightly better compared to a control group, but the researchers found modest improvements in blood-glucose control, adherence to treatment and quality of life.
Skipping Medications Equals Poor Control
Diabetes-related complications could be reduced if individuals took their medications on a regular basis, argue researchers in Baltimore, Maryland. The researchers examined the relationship between A1C levels and adherence to medication dosing among a group of urban African-Americans.
Barriers to medication adherence included
- forgetting to take medications
- running out of medications
- stopping medications because the participants felt better
- carelessness in taking medications
The first two barriers were the most statistically significant in showing a trend toward higher A1Cs.
People With Diabetes Have More Sleep Disturbances
Having diabetes is associated with increased periodic breathing (a breathing pattern common in people with central nervous system disorders) during sleep and with disturbances in other sleep-breathing patterns, according to data collected from the Sleep Health Heart Study and reported by Washington, D.C., researchers.
In this study, 4,882 subjects had a history of cardiovascular disease, and 426 of these individuals had diabetes. It was found that the "adjusted prevalence of periodic breathing in [people with diabetes] was nearly twice that of [people without diabetes]."
Beta-Cell Mass Decreases in Type 2 Diabetes; Fails to Regenerate
In postmortem examination, obese people who did not have type 2 diabetes showed a 52 percent increase in fractional beta-cell mass. In contrast, those who had had type 2 diabetes showed a decline of 60 percent, report researchers from Stockholm, Sweden; Los Angeles, California; and Boston, Massachusetts; who studied the pancreases of people with well-documented medical histories.
The beta-cell deficit also was found in people who had had impaired fasting glucose. The findings led the researchers to speculate that beta-cell mass declines before type 2 diabetes appears. In addition, say the researchers in another report, people with type 2 diabetes fail to generate new beta-cell formation, whereas regeneration is present in those without type 2 diabetes.
TZD Converts Experience Changes in Lipid Profile
Despite improving blood-glucose control after switching from Rezulin to Avandia or Actos, some individuals with type 2 diabetes also experience changes in lipid profiles.
Over the course of 12.6 months, North Carolina researchers observed 100 people who switched from Rezulin to Avandia or Actos. These three medications are all insulin sensitizers known as thiazolidinediones (TZDs).
Rezulin was banned by the U.S. Food and Drug Administration more than two years ago because of adverse events, including death, related to liver disease in some users.
Of the 51 people in the study who switched to Actos, average cholesterol levels decreased from 188.6 to 185.5 mg/dl. In addition, triglycerides decreased from 215.1 to 142.9 mg/dl, while LDL (bad) cholesterol levels decreased from 102.2 to 98.7 mg/dl. Only two of the 51 people had to increase their doses of lipid-lowering agents.
Of the 49 people who switched to Avandia, average cholesterol levels increased from 178.5 to 185.3 mg/dl. Triglycerides increased from 169.5 to 190.6 mg/dl, and LDL cholesterol levels increased from 99.8 to 103 mg/dl. Five Avandia users required more potent lipid-lowering agents after the conversion.
Four Studies Give Kudos to Lantus
Lantus Plus Humalog: Lower A1Cs and Fewer Nighttime Lows
Insulin glargine (Lantus)—whether given before breakfast (6 to 9 a.m.), dinner (6 to 8 p.m.) or bedtime (9 p.m. to midnight)—"is safe and effective" and is "associated with a lower rate of nighttime hypoglycemia" when used in combination with insulin lispro (Humalog).
German researchers evaluated 378 people with type 1 diabetes, ages 18 to 68, in a 24-week study. The participants took a once-daily injection of Lantus at one of the three specified times and took mealtime Humalog separately.
All participants achieved a similar reduction in A1C levels from the beginning to end of the study (breakfast injection group: 7.6% to 7.4%; dinner group: 7.6% to 7.5%; bedtime group: 7.6% to 7.5%). Fewer people taking Lantus at breakfast experienced symptoms of nighttime hypoglycemia (59.5 percent) than those who took it at dinner (71.9 percent) or bedtime (77.5 percent). The researchers note, however, that people in the breakfast group "showed a trend toward more episodes of daytime hypoglycemia."
Lantus Combined With Metformin Improves BG Control in Type 2s
In addition to improving blood-glucose control with less risk of hypoglycemia, Lantus in combination with metformin also has beneficial effects on lipids and prevents weight gain, according to German researchers.
In a 12-week study, 42 obese people with type 2 diabetes took Lantus once daily at bedtime and also took 850 mg of metformin twice daily. At the study's end, fasting blood glucose decreased from an average of 238 to 105 mg/dl. Triglycerides dropped from an average of 238 to 207 mg/dl.
No changes in body weight were reported over the course of the study, and none of the subjects experienced episodes of low blood glucose. Six people reported the common side effects associated with metformin use (diarrhea and abdominal discomfort).
Lantus Reduces Lows in Youngsters With Type 1
Researchers in Denver, Colorado, say Lantus therapy in children with type 1 diabetes is "useful in reducing severe hypoglycemic episodes."
Of the 140 people, ages 2 to 21, who participated in the study, 73 were treated with Lantus once daily and also with NPH and Humalog in the morning and Humalog before dinner. The remaining 67 received Lantus once daily and Humalog at mealtimes.
"Severe hypoglycemic episodes, requiring help, were reduced from a total of 11 in the three months prior to starting Lantus to three in the three months after Lantus [use began]," write the researchers.
The children's major complaint was having to take more injections after starting Lantus therapy. Before the study, 54 percent of participants received two injections per day, 42 percent received three or more and 4 percent were on the pump. After starting Lantus, 42 percent received three injections per day, and 58 percent received four or more.
A Little Lantus Can Decrease Chances of DKA in Pumpers
Using injections of Lantus to replace a percentage of basal insulin needs can help alleviate diabetic ketoacidosis in insulin pumpers who are prone to, or at high risk for, the condition.
Subjects in a randomized cross-over study replaced between 39 and 53 percent of their basal insulin needs with Lantus, with a corresponding reduction in basal insulin infusion rates. Re-searchers used a continuous glucose monitoring system to monitor subjects.
This method could also allow pumpers to safely disconnect during contact sports or for prolonged periods.
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