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Shutting Off the TV and Getting Outside Could Reduce Diabetes Risk
Scientists from Harvard University conducted a meta-analysis of many prospective cohort studies that measured the relationship between type 2 diabetes, cardiovascular disease, and all-cause mortality and television viewing. The analysis, published in JAMA on June 15, 2011, included 4 studies that directly measured the relationship between the risk of developing type 2 diabetes and the hours of television watched per day.
An analysis of the results of the 4 studies showed a linear increase in risk with the number of hours per day of TV viewing for both type 2 diabetes and cardiovascular disease, with a greater association with all-cause mortality when TV viewing time was greater than 3 hours per day.
The researchers do not believe TV viewing itself is responsible for the perceived increase in risk, of course, and instead attribute this increased risk to a decreased propensity for physical activity. Although the researchers warn that many of the studies analyzed could have an inherent bias (many of them were underpowered), they do note that there have been studies that have shown that a sedentary lifestyle leads to increased insulin resistance and detrimental postprandial lipid metabolism. PT
Diabetics at High Risk for Recurrent Stroke
In a post hoc analysis of the Stroke Prevention by Aggressive Reduction of Cholesterol Levels (SPARCL) trial, published in the Archives of Neurology on June 13, 2011, researchers have found that patients with type 2 diabetes are at an increased risk of recurrent ischemic or hemorrhagic stroke or transient ischemic attack (TIA) compared with patients without diabetes.
The SPARCL trial was a large, randomized, placebo-controlled trial that enrolled women and men older than 18 years who had an ischemic or hemorrhagic stroke or TIA 1 to 6 months before randomization. The study randomized patients to receive either statin or placebo therapy and measured the time from randomization after an ischemic stroke or TIA to the occurrence of a nonfatal or fatal stroke. The researchers also classified patients as having type 2 diabetes, no type 2 diabetes but metabolic syndrome, or no type 2 diabetes and no metabolic syndrome (the reference group), and then calculated their risk for having a recurrent stroke.
Although there was no difference in incidence of primary ischemic strokes between patients with and without diabetes, diabetic patients were at increased risk of secondary stroke compared with nondiabetic patients (18.1% vs 10.7% in the metabolic syndrome group and 11% in the reference group, P <.001).
The analysis also showed that there is no significant difference in risk reduction with statin therapy between diabetic and nondiabetic patients, emphasizing the importance of lipid-lowering therapy in all patients who present with dyslipidemia.
In Curbing Diabetes Risk, Counting Sheep May Be an Answer
Researchers at the 25th Anniversary Meeting of the Associated Sleep Professional Societies in Minneapolis, Minnesota, presented a study that showed that chronic sleep deprivation can increase insulin resistance in people at higher risk of developing type 2 diabetes.
The study enrolled 47 healthy participants with an average age of 26 years who had a normal body mass index (BMI) and a family history of type 2 diabetes in at least 1 first-degree relative. Participants were divided into 2 groups based on reported sleep schedule: short sleepers (<6 hours per night, and, hence, chronically sleep deprived) and usual sleepers (6 or more hours per night). The researchers also conducted oral glucose-tolerance testing on the participants, measured a fasting plasma glucose, and evaluated insulin sensitivity as well as beta-cell function.
The study showed that, when adjusted for differences in daily physical activity, age, BMI, sex, and ethnicity, short sleepers had a significantly higher insulin sensitivity index score than usual sleepers (7.7 vs 11.4, P = .013) but no significant difference in beta-cell function.
The presenters of the study believe this preservation of betacell function is due to the participants’ young age and that, if the insulin resistance persists for enough time, beta-cell function will decrease as the participants get older. In addition to an increase in physical exercise and dietary modifications, the results of this study show sleep hygiene may also be important in decreasing the risk for developing diabetes.