Estimation of glucose utilization in a type 2 diabetes mellitus patient on insulin analogs with tumor hypoglycemia induced by IGF-II.

We present a 38-year-old male patient with insulin requiring type 2 diabetes mellitus (DM) who had fasting hypoglycemia caused by a non-pancreatic-islet-cell mesenchymal tumor producing IGF-II. The evaluation was confounded in that there was pre-existing DM being treated with insulin analogs. Insulin levels were assessed with an immunoassay with cross reactivity with the insulin analogs. An 18-Fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) scan localized the 19.7×18.0×17.8cm retroperitoneal mass. A 3.25kg tumor was resected. Post-operatively insulin treatment was resumed and circulating IGF-II levels returned to normal. The maximum standardized uptake values of FDG (SUVmax) along with a steady state glucose infusion of 17.5g/h were used to determine the components of glucose utilization due to IGF-II induced muscle glucose uptake (utilization, 62%) whereas the tumor itself was responsible for approximately 22% of measurable glucose uptake. Whereas tumor induced hypoglycemia has been ascribed to preferential glucose utilization by the tumor, the predominant hypoglycemic effect was due to hormonal IGF-II induced total body glucose uptake.

Weight loss in obese older adults increases serum sclerostin and impairs hip geometry but both are prevented by exercise training.

We reported that weight loss induces bone loss which is prevented by exercise training; however, the mechanism for this observation remains unclear. Sclerostin, an inhibitor of bone formation, has been found to increase in states of unloading and may mediate the changes in bone metabolism associated with weight loss and exercise. The objective of the study was to determine the effect of lifestyle intervention in obese older adults on sclerostin levels, and on hip geometry parameters. A total of 107 obese (body mass index [BMI] ≥ 30 kg/m(2)) older (≥65 years) adults were randomly assigned to control, diet, exercise, and combined diet-exercise for 1 year. Sclerostin levels were measured by ELISA at baseline, 6 months, and 12 months, while hip geometry parameters were obtained from bone mineral density (BMD) images done by dual-energy X-ray absorptiometry using hip structure analysis at baseline and 12 months. Both the diet and diet-exercise groups had significant decreases in body weight (-9.6% and -9.4%, respectively), whereas weight was stable in the exercise and control groups. Sclerostin levels increased significantly and progressively in the diet group (6.6% ± 1.7% and 10.5% ± 1.9% at 6 and 12 months, respectively, all p < 0.05), whereas they were unchanged in the other groups; in particular, they were stable in the diet-exercise group (0.7% ± 1.6% and 0.4% ± 1.7% at 6 and 12 months, respectively, all p = 0.05). Hip geometry parameters showed significant decreases in cross-sectional area, cortical thickness, and BMD; and increases in buckling ratio at the narrow neck, intertrochanter, and femoral shaft. These negative changes on bone geometry were not observed in the diet-exercise group. Significant correlations between changes in sclerostin and changes in certain hip geometry parameters were also observed (p < 0.05). In conclusion, the increase in sclerostin levels with weight loss that was prevented by exercise may partly mediate the negative effects of weight loss on bone metabolism and the osteoprotective effect of exercise training.

Exercise training in obese older adults prevents increase in bone turnover and attenuates decrease in hip bone mineral density induced by weight loss despite decline in bone-active hormones.

Weight loss therapy to improve health in obese older adults is controversial because it causes further bone loss. Therefore, it is recommended that weight loss therapy should include an intervention such as exercise training (ET) to minimize bone loss. The purpose of this study was to determine the independent and combined effects of weight loss and ET on bone metabolism in relation to bone mineral density (BMD) in obese older adults. One-hundred-seven older (age >65 years) obese (body mass index [BMI] ≥ 30 kg/m(2) ) adults were randomly assigned to a control group, diet group, exercise group, and diet-exercise group for 1 year. Body weight decreased in the diet (-9.6%) and diet-exercise (-9.4%) groups, not in the exercise (-1%) and control (-0.2%) groups (between-group p < 0.001). However, despite comparable weight loss, bone loss at the total hip was relatively less in the diet-exercise group (-1.1%) than in the diet group (-2.6%), whereas BMD increased in the exercise group (1.5%) (between-group p < 0.001). Serum C-terminal telopeptide (CTX) and osteocalcin concentrations increased in the diet group (31% and 24%, respectively), whereas they decreased in the exercise group (-13% and -15%, respectively) (between-group p < 0.001). In contrast, similar to the control group, serum CTX and osteocalcin concentrations did not change in the diet-exercise group. Serum procollagen propeptide concentrations decreased in the exercise group (-15%) compared with the diet group (9%) (p = 0.04). Serum leptin and estradiol concentrations decreased in the diet (-25% and -15%, respectively) and diet-exercise (-38% and -13%, respectively) groups, not in the exercise and control groups (between-group p = 0.001). Multivariate analyses revealed that changes in lean body mass (ß = 0.33), serum osteocalcin (ß = -0.24), and one-repetition maximum (1-RM) strength (ß = 0.23) were independent predictors of changes in hip BMD (all p < 0.05). In conclusion, the addition of ET to weight loss therapy among obese older adults prevents weight loss-induced increase in bone turnover and attenuates weight loss-induced reduction in hip BMD despite weight loss-induced decrease in bone-active hormones.

Weight loss, exercise, or both and physical function in obese older adults.

BACKGROUND: Obesity exacerbates the age-related decline in physical function and causes frailty in older adults; however, the appropriate treatment for obese older adults is controversial. METHODS: In this 1-year, randomized, controlled trial, we evaluated the independent and combined effects of weight loss and exercise in 107 adults who were 65 years of age or older and obese. Participants were randomly assigned to a control group, a weight-management (diet) group, an exercise group, or a weight-management-plus-exercise (diet-exercise) group. The primary outcome was the change in score on the modified Physical Performance Test. Secondary outcomes included other measures of frailty, body composition, bone mineral density, specific physical functions, and quality of life. RESULTS: A total of 93 participants (87%) completed the study. In the intention-to-treat analysis, the score on the Physical Performance Test, in which higher scores indicate better physical status, increased more in the diet-exercise group than in the diet group or the exercise group (increases from baseline of 21% vs. 12% and 15%, respectively); the scores in all three of those groups increased more than the scores in the control group (in which the score increased by 1%) (P<0.001 for the between-group differences). Moreover, the peak oxygen consumption improved more in the diet-exercise group than in the diet group or the exercise group (increases of 17% vs. 10% and 8%, respectively; P<0.001); the score on the Functional Status Questionnaire, in which higher scores indicate better physical function, increased more in the diet-exercise group than in the diet group (increase of 10% vs. 4%, P<0.001). Body weight decreased by 10% in the diet group and by 9% in the diet-exercise group, but did not decrease in the exercise group or the control group (P<0.001). Lean body mass and bone mineral density at the hip decreased less in the diet-exercise group than in the diet group (reductions of 3% and 1%, respectively, in the diet-exercise group vs. reductions of 5% and 3%, respectively, in the diet group; P<0.05 for both comparisons). Strength, balance, and gait improved consistently in the diet-exercise group (P<0.05 for all comparisons). Adverse events included a small number of exercise-associated musculoskeletal injuries. CONCLUSIONS: These findings suggest that a combination of weight loss and exercise provides greater improvement in physical function than either intervention alone. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00146107.).