Time to get started on our monthly headlines and abstracts which this month will concern the association of waist circumference prediction of diabetes and cardiovascular disease and active smoking and the risk of type 2 diabetes. Our first headline is about Vitamin E and heart attacks. Researchers in Israel under the leadership of Dr. Andrew Levy of the Technion Faculty of Medicine have determined that vitamin E supplements can substantially cut the risk of heart attacks and related deaths for diabetics with a specific gene which accounts for 40 % of diabetics. The test for this gene Hp2-2 is available commercially so here is one more thing to talk over with your physician. This information is available in the Nov.21 online edition of the journal Arteriosclerosis, Thrombosis, and Vascular Biology.
The Nature Medicine journal has an article about the long term usage of the diabetes drug Avandia which could be linked to an increase in bone fractures and the development of osteoporosis. Rosiglitazone, otherwise known as Avandia, is used to treat patients with Type 2 diabetes. Pharmaceutical manufactured GlaxoSmithKline has noted the side effects of Avandia include heart failure, and the drug has also led to an increase in bone fractures in female patients. Patients prone to bone fractures were formerly believed to have weaker bones due to lack of bone building cellular activity, rather than actual bone removal. This new insight into previously unrecognized aspect of bone physiology should have important medical consequences according to the authors. They added that discretion should be exercised for long-term use of Rosiglitazone in patients prone to bone fractures, specifically women, though the treatment could be useful in conjunction with anti-osteoporosis drugs.
Black American women and Chinese women who ate foods high on the glycemic index—which measures the effect of carbohydrates on blood glucose levels—were at increased risk for developing type 2 diabetes, two studies found. In the first study at Boston University School of Public Health researchers examined data on more than 40,000 black women who filled out a questionnaire in 1995. Every two years through 2003, the women provided update on weight, health and other information. During this time 1,938 of the women developed type 2 diabetes. Women who ate high-glycemic index foods or ate a diet with a high glycemic load were more likely to develop diabetes than women who ate more cereal fiber. “Incorporating fiber sources into the diet is relatively easy: A simple change from white bread to whole wheat bread will move a person from a low fiber intake to a moderate intake category, with a corresponding 10 per cent reduction in risk." In the second study, researchers at Vanderbilt University Medical Center followed Chinese female subjects for an average of five years. During the study, 1,608 women developed diabetes. High consumption of carbohydrates increased the risk of diabetes. Women who consumed the most carbohydrates had a 28 percent greater risk of developing diabetes than those who consumed the least grams. Women who had high glycemic index diets and who ate food staples such as bread, noodles and rice also had an increased risk of developing diabetes. For example, those who ate more than 300 grams of rice per day were 78 percent more likely to develop diabetes than those who ate less than 200 grams of rice per day. The researchers stated that “given that a large part of the world’s population consumes rice and carbohydrates as the mainstay of their diets the prospective data linking intake of refined carbohydrates to increased risk of type 2 diabetes mellitus may have substantial implications for public health".
Finally Journal Watch, Nov. 15, 2007 shared information about the various options for starting insulin in patients wit type 2 diabetes. In a trial—dubbed “4T—“Treating to Target in Type 2 Diabetes,— researchers in the UK compared thee options which was reported in the New England Journal of Medicine, Oct. 25, 2007. The study included 700 adults with type 2 diabetes and HA1c levels between 7% and 10% despite treatment with sulfonylurea plus metformin. Patients with persistent hypoglycemia were excluded. The patients continued their oral agents initially and were randomized to biphasic insulin aspart 30 twice/day, prandial insulin aspart three times/day, or basal insulin detemir one/day. A protocol specified dose titration, glucose monitoring, and follow-visits. During the year follow-up, four outcomes were observed. 1. The average fall in HA1c was greater for the biphasic and prandial groups than the basal group. 2. The proportion of patients with HA1c levels of 6.5% or less was also significantly greater in biphasic and prandial groups than the basal and was best in those patients in those whose baseline HA1c was greater the 8.5%. 3. Symptomatic hypoglycemia was more common with prandial than biphasic insulin, and with biphasic than basal insulin. 4. The patients in the basal group gained less weight than did those in the other two groups. After looking at the results, the researchers concluded that basal insulin once a day is probably the best initial approach for starting insulin in patients with type 2 diabetes. If good glycemic control isn’t achieved more complex regimes will be examined in the next 2 years of this trial. The editorialists state a preference for glargine (Lantus) as a basal insulin because it seems to have less of a peak and is slightly longer-acting than detemir and they believe the sulfonylureas should be stopped when insulin is begun because their mechanism of action isn’t synergistic with insulin.
Pull up your cup of coffee because we are going to share some journal abstracts. Our first titled Does Waist Circumference Predict Diabetes and Cardiovascular Disease Beyond Commonly Evaluated Cardiometabolic Risk Factors? by Peter M. Janiszewski, MSC, et al. in Diabetes Care 30:31505-3109, 2007. While the measurement of waist circumference (WC) is recommended in current clinical guidelines, its clinical utility was questioned in a recent consensus statement. In response the researchers from Canada sought to determine whether WC predicts diabetes and cardiovascular disease (CVD) beyond that explained by BMI and commonly obtained cardiometabolic risk factors including blood pressure, lipoproteins, and glucose. Subjects consisted of 5,882 adults from the 199902004 National Health and Nutrition Examination Survey, which is nationally representative and cross-sectional. Subjects were grouped into sex-specific WC and BMI tertiles. Blood pressure, triglycerides, LDL and HDL cholesterol, and glucose were categorized using standard clinical thresholds. Logistic regression analyses were used to calculate the odds for diabetes and CVD according to WC tertiles.
After controlling for basic confounders, the medium and high WC tertiles were more likely to have diabetes and CVD compared with low WC tertile. After inclusion of BMI and cardiometabolic risk factors in the regression models, the magnitude of the odds ratios were attenuated (i.e., for diabetes the magnitude decreased from 6.54 to 5.03 for the high WC group) but remained significant in the medium and high WC tertiles for the prediction of diabetes not for CVD.
The researchers concluded that WC predicted diabetes, but not CVD, beyond that explained by traditional risk factors and BMI. The findings lend critical support for the recommendation that WC be a routine measure for identification of the high-risk, abdominally obese patient.
Our next abstract is titled Active Smoking and the Risk of Type 2 Diabetes, A Systematic Review and Meta-Analysis, by Carole Willi, MD et al in JAMA 2007;298 (22):2654-2664. Observational studies have suggested an association between active smoking and the incidence of type 2 diabetes. The objective of this study was to conduct a systematic review with meta-analysis of studies assessing the association between active smoking and the incidence of type 2 diabetes. A search of MRDLINE (1966 to May 2007) and EMBASE (1980 to May 2007) databases was supplemented by manual searches of bibliographies of key retrieved articles, reviews of abstracts from scientific meetings, and contact with experts. Studies were included if they reported risk of impaired fasting glucose, impaired glucose tolerance, or type 2 diabetes in relationship to smoking status at baseline; had a cohort design; and excluded persons with diabetes at baseline. Two authors independently extracted the data, including the presence or absence of active smoking at baseline, the risk of diabetes, methods used to detect diabetes, and key criteria of study quality. Relative risks (RRs) were pooled using a random-effects model. Associations were tested in subgroups representing different patient’s characteristics and study quality criteria. The search yielded 25 prospective cohort studies (N=1.2 million participants) that reported 45,844 incident cases of diabetes during the follow-up period ranging from 5 to 30 years. Of the 25 studies, 24 reported adjusted RRs greater than 1 (range for all studies, 0.82-3.74). The pooled adjusted RR was 1.44. Results were consistent and statistically significant in all subgroups. The risk of diabetes was greater for heavy smokers than for lighter smokers and lower for former smokers; compared with active smoker, consistent with a dose-response phenomenon.
The authors concluded that active smoking is associated with an increased risk of type 2 diabetes. Future research should attempt to establish whether this association is casual and to clarify its mechanisms.
BSP
