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T2D Prevention Less Effective With Impaired Fasting Glucose?

Health factors and behaviors recommended by the American Heart Association (AHA) to reduce cardiovascular risk also dramatically lowered diabetes risk — but only in those with normal fasting glucose, researchers reported.

For individuals who already had impaired fasting glucose, following the recommendations did not seem to benefit their risk for developing diabetes, a research team led by Joshua Joseph, MD, of Ohio State University’s Wexner Medical Center in Columbus, said in the journal Diabetologia.

Joseph’s group examined associations between the AHA’s “Life’s Simple 7” — physical activity, diet, weight, cholesterol, blood pressure, blood glucose, and tobacco use — and incident diabetes risk in more than 7,000 individuals without diabetes at baseline. They found that individuals with normal fasting glucose who met four or more of the criteria had 80% lower diabetes risk compared to those who met only one or none (HR 0.20, 95% CI 0.10-0.37).

However, individuals with impaired fasting glucose who met four or more criteria had only a non-significant 13% decrease in risk (HR 0.87, 95% CI 0.58-1.30). In addition, the study found the magnitude of risk reduction was greater for whites than blacks who met four or more of the seven factors (73% vs 66%, P=0.0338). Finally, the investigators reported that age, sex, and history of coronary heart disease did not modify the association.

“In this large contemporary cohort study, a higher number of ideal cardiovascular health components at baseline showed a graded, inverse association with incident diabetes, consistent with previous studies. However, the magnitude of the association of ideal cardiovascular health with lower diabetes risk varied by glycemic status, with a strong inverse association observed among those with normal glucose and no association observed among those with impaired fasting glucose,” the study authors said.

“These findings suggest population-level public health promotion of the AHA 2020 ideal cardiovascular health metrics may be beneficial for primordial prevention of diabetes, but may not be as beneficial for preventing progression to diabetes from impaired fasting glucose,” they said. “The lower magnitude of risk reduction with ideal cardiovascular health among those with impaired fasting glucose warrants further investigation and suggests this group requires higher intensity interventions to lower long-term diabetes risk.”

Joseph and colleagues analyzed data on 7,758 participants without diabetes at baseline in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a prospective national cohort of more than 30,000 individuals age 45 or older. Mean age of study participants was 63 years, 73% were white vs 27% black, and 56% were women. Factors such as diet and physical activity were assessed with questionnaires, while biomarkers including blood pressure and cholesterol were directly measured. Over 9.5 years of follow-up, there were 891 incident cases of diabetes.

The investigators noted that only 10% of participants met four or more of the AHA criteria. Approximately 58% met two or three, and 32% met one or none. Fasting glucose was normal at baseline in 6,004 participants and impaired in 1,754.

Limitations of the study included its reliance on self-reports for diet and physical activity, that it did not assess the duration of physical activity, and that it did not include factors such as genetic susceptibility which could have affected the results, the study authors said.

Nevertheless, an important implication of the study is that prevention efforts must be initiated early, Joseph said in a statement. “Healthy people need to work to stay healthy,” he said. “Follow the guidelines. Don’t proceed to high blood sugar and then worry about stopping diabetes. By that point, people need high-intensity interventions that focus on physical activity and diet to promote weight loss and, possibly, medications to lower the risk of diabetes.”

Prescribing Exercise

Joseph’s advice was echoed by the European Society of Cardiology (ESC) in a new position paper providing detailed recommendations on exercise training in patients with diabetes and cardiovascular disease.

Physicians need to do more than simply recommend exercise, they must prescribe specific exercise programs tailored to the needs of each patient, Hareld Kemps, MD, of the Máxima Medical Centre in Veldhoven, The Netherlands, and colleagues said online in the European Journal of Preventive Cardiology.

“Just advising patients to exercise, which is what doctors typically do, is not enough,” Kemps said in a statement. “Patients must be assessed for comorbidities, risks related to exercise, and personal preferences. This will be cost effective in the long run so we have to wake up policy makers and healthcare insurers to pay for it. That needs clinicians to take the lead and call for programmes to be reimbursed.”

One key to the success of an exercise program is setting early goals for each patient that are achievable and measurable, the paper said. “For an elderly person this could be climbing the stairs in their home or walking to the supermarket – achievements that will really improve their quality of life,” Kemps said.

Another key is setting clinical targets for each patient, and then prescribing exercise known to improve that target, the paper recommended. For example, aerobic exercise has been shown to improve vascular function and lower blood pressure. Resistance training, on the other hand, can improve muscle strength and lower inflammation.

“However, the main common problem of all exercise interventions aiming at long-term improvements remains adherence,” the authors wrote. “We should therefore consider the importance of motivation, improving self-management skills, and integration of exercise into daily routine when designing exercise training programmes.”

The study by Joseph et al. was funded by the National Institutes of Health and the CDC. No authors reported relevant conflicts of interest.

The ESC position paper was not funded by any organization. The authors declared no conflicts of interest.


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