The incidence of diabetes mellitus (DM) continues to rise and has quickly become one of the most prevalent and costly chronic diseases worldwide. A close link exists between DM and cardiovascular disease (CVD), which is the most prevalent cause of morbidity and mortality in diabetic patients. Cardiovascular (CV) risk factors such as obesity, hypertension and dyslipidemia are common in patients with DM, placing them at increased risk for cardiac events. In addition, many studies have found biological mechanisms associated with DM that independently increase the risk of CVD in diabetic patients. Therefore, targeting CV risk factors in patients with DM is critical to minimize the long-term CV complications of the disease. This paper summarizes the relationship between diabetes and CVD, examines possible mechanisms of disease progression, discusses current treatment recommendations, and outlines future research directions.

Objective:Obesity in the United States is highly prevalent, approaching 60% for black women. We investigated whether nutrition education sessions at the work place added to internet-based wellness information and exercise resources would facilitate weight and fat mass loss in a racially diverse population of overweight female employees.Methods:A total of 199 (average body mass index 33.9±6.3 kg m−2) nondiabetic women (57% black) at our institution were randomized to a 6-month program of either internet-based wellness information (WI) combined with dietitian-led nutrition education group sessions (GS) weekly for 3 months and then monthly with shift in emphasis to weight loss maintenance (n=99) or to WI alone (n=100). All were given access to exercise rooms convenient to their work site. Fat mass was measured by dual-energy X-ray absorptiometry.Results:WI+GS subjects lost more weight than WI subjects at 3 months (−2.2±2.8 vs −1.0±3.0 kg, P>0.001). Weight (−2.7±3.9 vs −2.0±3.9 kg) and fat mass (−2.2±3.1 vs −1.7±3.7 kg) loss at 6 months was significant for WI+GS and WI groups (both P<0.001), but without significant difference between groups (both P>0.10); 27% of the WI+GS group achieved ⩾5% loss of initial weight as did 18% of the WI group (P=0.180). Blacks and whites similarly completed the study (67 vs 74%, P=0.303), lost weight (−1.8±3.4 vs −3.3±5.2 kg, P=0.255) and fat mass (−1.6±2.7 vs −2.5±4.3 kg, P=0.532), and achieved ⩾5% loss of initial weight (21 vs 32%, P=0.189), irrespective of group assignment.Conclusion:Overweight women provided with internet-based wellness information and exercise resources at the work site lost weight and fat mass, with similar achievement by black and white women. Additional weight loss benefit of nutrition education sessions, apparent at 3 months, was lost by 6 months and may require special emphasis on subjects who fail to achieve weight loss goals to show continued value.

Obesity disproportionately affects women, especially those of African descent, and is associated with increases in both fat and muscle masses. Although increased extremity muscle mass may be compensatory to fat mass load, we propose that elevated insulin levels resulting from diminished insulin sensitivity may additionally contribute to extremity muscle mass in overweight or obese women. The following measurements were performed in 197 non-diabetic women (57% black, 35% white; age 46±11 years [mean±SD], BMI range 25.0 to 57.7 kg/m2): dual-energy X-ray absorptiometry for fat and extremity muscle masses; exercise performance by duration and peak oxygen consumption (VO2 peak) during graded treadmill exercise; fasting insulin and in 183 subjects insulin sensitivity index (SI) calculated from the minimal model. SI (range 0.5 to 14.1 liter/mU−1•min−1) was negatively, and fasting insulin (range 1.9 to 35.6 μU/mL) positively, associated with extremity muscle mass (both P<0.001), independent of age and height. Sixty-seven percent of women completed 6 months of participation in a weight loss and exercise program: We found a significant association between reduction in fasting insulin and a decrease in extremity muscle mass (P=0.038), independent of reduction in fat mass or improvement in exercise performance by VO2 peak and exercise duration, and without association with change in SI or interaction by race. Thus, hyperinsulinemia in overweight or obese women is associated with increased extremity muscle mass, which is partially reversible with reduction in fasting insulin concentration, consistent with stimulatory effects of insulin on skeletal muscle.

ObjectiveWeight loss interventions have produced little change in insulin sensitivity in black women, but mean data may obscure metabolic benefit to some and adverse effects for others. Accordingly, we analyzed insulin sensitivity relative to fat mass change following a weight loss program.Design and MethodsFifty-four black women (BMI range 25.9 to 54.7 kg/m2) completed the 6-month program that included nutrition information and worksite exercise facilities. Fat mass was measured by dual-energy X-ray absorptiometry, and insulin sensitivity index (SI) was calculated from an insulin-modified intravenous glucose tolerance test using the minimal model.ResultsBaseline SI (range 0.74 to 7.58 l/mU−1•min−1) was inversely associated with fat mass (r = −0.516, p < 0.001), independent of age. On average, subjects lost fat mass (baseline 40.8 ± 12.4 to 39.4 ± 12.6 kg [mean ± SD], P < 0.01), but 17 women (32 %) actually gained fat mass. SI for the group was unchanged (baseline 3.3 ± 1.7 to 3.2 ± 1.6, P = 0.67). However, the tertile with greatest fat mass loss (−3.6 kg, range −10.7 to −1.7 kg) improved insulin sensitivity (SI +0.3 ± 1.2), whereas the tertile with net fat mass gain (+0.9 kg, range −0.1 to +3.8 kg) had reduced insulin sensitivity (SI −0.7 ± 1.3) from baseline values (P < 0.05 by ANOVA).ConclusionsBlack women in a weight loss program who lose fat mass may have improved insulin sensitivity, but fat mass gain with diminished sensitivity is common. Additional support for participants who fail to achieve fat mass loss early in an intervention may be required for success.

Introduction Obesity is associated with many negative health impacts, including hyperinsulinemia and reduced exercise performance, despite being associated with greater lean skeletal mass which works as the insulin-targeting and exercising organ. Purpose of Study We delineated the associations amongst cardiorespiratory capacity, fat mass, skeletal mass distributions, and fasting plasma insulin in overweight, non-diabetic women. Methods One hundred and seventy-two sedentary women, age 22 to 68 years (range), body mass index (BMI) (34.2 ± 6.3 [mean ± SD]; range 25.3 to 57.6 kg/m 2 ), underwent dual energy x-ray absorptiometry for body composition, fasting insulin, and graded treadmill exercise test using the Bruce protocol with measurement of oxygen consumption (peak VO 2 ). Results After adjustment for age, fasting insulin (9.8 ± 8.1; range 1.9 to 47.6 mcU/ml) was positively associated with BMI (r = 0.43, p<0.001), fat mass (r = 0.41, p< 0.001), load-bearing skeletal muscle mass (lower extremity lean mass; r = 0.29, p< 0.001), and non-load-bearing skeletal muscle mass (upper extremity lean mass; Figure, Panel A). By multiple regression analysis with age, fat mass and lower and upper extremity lean masses as covariates, fat mass, age and upper extremity lean mass (Figure, Panel B) were independent negative predictors of peak VO 2 (all p< 0.01). Lower extremity, however, trended to be positively predictive of peak VO 2 (p = 0.067). Conclusions In non-load-bearing muscle, increased lean mass associated with elevated plasma insulin is predictive of reduced oxygen consumption during exercise, suggesting additional load that may diminish cardiorespiratory exercise performance or intrinsic impairment in skeletal muscle function. In load-bearing muscle, compensatory hypertrophy due to increased fat and lean mass loads may preserve exercise performance.

Background: As the epidemic of obesity in the United States steadily worsens, black women are disproportionately affected. Diminished insulin sensitivity has been linked with obesity and heightened risk of subsequent type 2 diabetes (T2D) and cardiovascular disease (CVD). Hypothesis: We propose that a decrease in fat mass achievable by weight loss intervention at the worksite improves insulin sensitivity in overweight black women. Methods: Fifty-four overweight black women [age 45±10 years (mean±SD), BMI range 25.9 to 54.7 kg/m 2 ] completed a 6-month program that included web-based nutrition information and/or dietitian counseling and access to exercise rooms near their work areas. All participants were advised to reduce daily caloric intake by 500 kcal and instructed to increase daily activity by 5,000 steps, measured by pedometer, above baseline readings. The following measurements were performed: weight, total fat mass by dual-energy X-ray absorptiometry, and insulin sensitivity index (S I ) calculated from the minimal model. Repeat of all measurements was performed at 6 months. Results: Baseline S I (median 3.0 liter/mU -1 •min -1 , range 0.74 to 7.58 liter/mU -1 •min -1 , with lower values signifying insulin resistance) was negatively associated with fat mass (r= -0.584, P<0.001) independent of age. Significant reductions in weight (92.6±18.1 to 91.1±18.9 kg, P<0.01) and fat mass (40.8±12.4 to 39.4±12.6 kg, P<0.01) were determined for subjects completing the program. Reduction in fat mass following completion of the program was associated with an increase in S I (r= -0.293, P=0.032). When analyzed by tertiles of fat mass change (Figure), compared to the tertile with net fat mass gain (far left bar), the two tertiles with net fat mass loss had significantly improved insulin sensitivity (higher S I ). Conclusions: Even modest fat mass reduction in overweight non-diabetic black women with a combination of diet and exercise can improve insulin sensitivity, which has the potential to reduce or delay the onset of T2D and CVD.