New research was presented at ENDO 2019, the annual meeting of the Endocrine Society, from March 23-26 in New Orleans. The features below highlight some of the studies that emerged from the conference.
Uphill Vs Downhill Treadmill Exercise in Postmenopausal Diabetics
Although data suggest that bone structure integrity is supported by mechanical loading, energy intake, and sex hormones, when postmenopausal diabetics experience more bone breaks despite higher body weight and positive energy balance compared with non-diabetics remains unclear. With the hypothesis that greater bone fragility in postmenopausal diabetics may result from peripheral insulin resistance and reduced nutrient access to the bone, researchers assigned postmenopausal diabetic women to participate in two of five experimental conditions: no exercise, walking uphill before a standardized meal, walking uphill after the meal, walking downhill before the meal, and walking downhill after the meal, on a treadmill that could be tilted upward or downward as desired. Participants assigned to walk uphill exerted a greater mean effort than those in the downhill group (75.2% vs 47.9%), whereas the downhill condition created a 38% greater strike force, with the increased mechanical loading helping to mitigate bone mass loss. When compared with pre-meal exercise among those who walked downhill, post-meal exercise increased c-terminal propeptide of type I collagen by 44% and was associated with a 40% greater osteogenic ratio. Meals lowered bone resorption among all women.
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Hormone Therapy for Overweight & Obese Men
Prior research indicates that the hypothalamic neurohormone oxytocin holds promised as a novel treatment for obesity. However, the mechanisms underlying oxytocin effects on caloric intake are not well defined. To better understand the mechanisms by which oxytocin exerts its anorexigenic effects, study investigators employed a dynamic method of functional MRI (fMRI) analysis, functional connectivity, which refers explicitly to the influence that one neural system exerts over another in a context-dependent manner. Overweight or obese men who were otherwise healthy presented after a 10-hour fast, and 60 minute after being administered oxytocin or placebo, started an established fMRI food-motivation paradigm that included images of high- and low-calorie foods, household objects, and fixation stimuli. Those who were administered oxytocin showed significant attenuation of the functional connectivity between the ventral tegmental area and insula, parietal operculum, amygdala, anterior and posterior cingulate, and hippocampus in response to viewing high-calorie food stimuli vs. objects when compared with those who were administered placebo. “This is particularly relevant to obese individuals, since previous studies have shown greater activation to palatable food images in these areas… and it has been proposed that this hyperactivity of the dopaminergic reward circuit renders obese individuals prone to overeating,” conclude the study authors.
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A1C Misses Many Diabetes Cases
Although the American Diabetes Association guidelines include statements regarding the use of oral glucose-tolerance tests and not relying solely on the A1C for diagnosing diabetes, A1C has become the primary method of screening and diagnosing the condition. To determine the reliability of A1C in diagnosing diabetes, researchers analyzed data on 9,000 adults without a diabetes diagnosis. When compared with oral glucose-tolerance testing, A1C over-diagnosed glucose tolerance by 42% and under-diagnosed diabetes in 73% of adults. For diagnosing diabetes, A1C had a sensitivity of about 27% and a specificity of about 99%. For determining normal glucose tolerance, A1C had a sensitivity of about 85% and a specificity of about 44%. A1C accuracy varied across races and ethnicity, ranging from a sensitivity of approximately 41% in African Americans to about 21% in Caucasians. The study investigators suggest that clinicians not rely solely on A1C for diagnosing diabetes.
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Guidance on Managing Older Adults With Diabetes
The document Treatment of Diabetes in Older Adults: An Endocrine Society Clinical Practice Guideline was presented at ENDO 2019 to help address the numerous complex issues involved in managing the growing population of older adults with diabetes. The document covers screening, prevention, and management of glycemia, blood pressure, and lipids, as well as comorbidities, complications, and special situations such as diabetes care in the hospital and long-term care facilities, and management of type 1 diabetes in older adults. Regular screening in this population is recommended for prediabetes and diabetes to allow for earlier intervention. The guideline also emphasizes shared decision-making and provides a framework to assist healthcare providers to individualize treatment goals. Other specific aging-related comorbidities and issues addressed in the guidelines include sarcopenia, frailty, cognitive dysfunction, diminished medication adherence, renal disease, cardiac disease, and loss of independence in daily living activities. Avoidance of hypoglycemia, aggressive blood pressure lowering, and medication adjustments are addressed as well.
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Evaluating Glycemic Markers & Hypoglycemia Risk in T2DM & CKD
Evidence indicates that managing type 2 diabetes mellitus (T2DM) is challenging in the presence of advancing non-dialysis chronic kidney disease (n-CKD). However, prior research has not confirmed the accuracy of markers such as serum fructosamine (SF) and A1C in this population. Data are also lacking on the incidence of hypoglycemia in these patients. To evaluate the accuracy of A1C and explore the frequency and severity of hypoglycemia in T2DM patients with n-CKD by continuous glucose monitoring (CGM), researchers assessed data on patients with T2DM and n-CKD who wore CGMs for a mean of 12.6 days. A1C was found to correlate significantly with average glucose concentration (AGC), characterized by the formula AGC=31.8 x A1C – 73.3. No significant correlations were observed, however, between SF and AGC. Hypoglycemic episodes were experienced by 76% of patients, ranging from zero to 53 and with a mean number of minutes of hypoglycemia of 1,501.
