Review and Implications of Intergenerational Communication and Social Support in Chronic Disease Care and Participation in Health Research of Low-Income, Minority Older Adults in the United States.

Background: Health disparities disproportionally affect Black and Hispanic older US adults. Health research is needed to understand and eliminate these disparities; however, older adults, and particularly Black and Hispanic/Latino older adults are underrepresented in health research. Adult children have influenced health behavior and health outcomes of their older parents in several demographics in the US. Analysis of these studies can lead to a model for the development of interventions aimed at improving health and healthcare participation of older Black and Hispanic US adults. Objectives: To review the role of intergenerational communication and social support in health behavior, health research, and health outcomes for older adults and to apply these findings toward a model for health interventions for Black and Hispanic US older adults. Methods: An analytical narrative review and application toward an intervention model. Results: Key topic areas were reviewed and analyzed by examining studies that applied forms of intergenerational communication and/or intergenerational social support with the goal of either improving health, disease management and/or participation in health research in populations world-wide. Next, a model for providing health interventions in older Black and Hispanic US adults was developed using strategies gleaned from the findings. Conclusion: A model for health intervention for Black and Hispanic/Latino US older adults was presented based on an analytical review and intergenerational communication and/or social support. Qualitative data are necessary to understand the enablers and barriers of intergenerational communication and social support to improve health outcomes in these populations.

Assessing the predictive accuracy of oral glucose effectiveness index using a calibration model.

PURPOSE: Current reference methods for measuring glucose effectiveness (GE) are the somatostatin pancreatic glucose clamp and minimal model analysis of frequently sampled intravenous glucose tolerance test (FSIVGTT), both of which are laborious and not feasible in large epidemiological studies. Consequently, surrogate indices derived from an oral glucose tolerance test (OGTT) to measure GE (oGE) have been proposed and used in many studies. However, the predictive accuracy of these surrogates has not been formally validated. In this study, we used a calibration model analysis to evaluate the accuracy of surrogate indices to predict GE from the reference FSIVGTT (SgMM). METHODS: Subjects (n = 123, mean age 48 ± 11 years; BMI 35.9 ± 7.3 kg/m2) with varying glucose tolerance (NGT, n = 37; IFG/IGT, n = 78; and T2DM, n = 8) underwent FSIVGTT and OGTT on two separate days. Predictive accuracy was assessed by both root mean squared error (RMSE) of prediction and leave-one-out cross-validation-type RMSE of prediction (CVPE). RESULTS: As expected, insulin sensitivity, SgMM, and oGE were reduced in subjects with T2DM and IFG/IGT when compared with NGT. Simple linear regression analyses revealed a modest but significant relationship between oGE and SgMM (r = 0.25, p < 0.001). However, using calibration model, measured SgMM and predicted SgMM derived from oGE were modestly correlated (r = 0.21, p < 0.05) with the best fit line suggesting poor predictive accuracy. There were no significant differences in CVPE and RMSE among the surrogates, suggesting similar predictive ability. CONCLUSIONS: Although OGTT-derived surrogate indices of GE are convenient and feasible, they have limited ability to robustly predict GE.

The Metabolic Syndrome and Its Components in African-American Women: Emerging Trends and Implications.

The Metabolic Syndrome (MetS) is recognized as a predictor of cardiovascular outcomes and type 2 diabetes (T2DM). The MetS is a constellation of clinical and metabolic risk factors that include abdominal obesity, dyslipidemia, glucose intolerance, and hypertension. There are ethnic and racial differences in the prevalence of MetS and its components. In general, African-Americans have lower prevalence of MetS when compared to whites, but suffer disproportionately from higher cardiovascular mortality and T2DM. Specifically, African-American women (AAW) have higher rates of T2DM and cardiovascular mortality despite a more favorable lipid and lipoprotein profile. This is paradoxical. However, there is a general upward trend in the prevalence of MetS in the US. The reasons are debatable, but could be multifactorial, including genetics and environmental factors. Thus, there is a need to understand the increasing trend in the MetS, its components, and the associated outcomes for AAW. Therefore, the purpose of this mini review is to (1) understand the increasing prevalence of MetS and its components in AAW and (2) provide suggestions for future prevention of cardiovascular disease and T2DM in AAW.

Racial Disparities in the Pathogenesis of Type 2 Diabetes and its Subtypes in the African Diaspora: A New Paradigm.

The global epidemic of diabetes has extended to the developing countries including Sub-Sahara Africa. In this context, blacks with type 2 diabetes in the African Diaspora continue to manifest 1.5-2 times higher prevalent rates than in their white counterparts. Previous studies have demonstrated that blacks with and without type 2 diabetes have alterations in hepatic and peripheral insulin sensitivity, beta-cell function, and hepatic insulin clearance as well as hepatic glucose dysregulation when compared to whites. In addition, non-diabetic blacks in the African Diaspora manifest multiple metabolic mediators that predict type 2 diabetes and its subtypes. These pathogenic modifiers include differences in subclinical inflammation, oxidative stress burden, and adipocytokines in blacks in the African Diaspora prior to clinical diagnosis. Consequently, blacks in the African Diaspora manifest subtypes of type 2 diabetes, including ketosis-prone diabetes and J type diabetes. Given the diversity of type 2 diabetes in blacks in the African Diaspora, we hypothesize that blacks manifest multiple early pathogenic defects prior to the diagnosis of type 2 diabetes and its subtypes. These metabolic alterations have strong genetic component, which appears to play pivotal and primary role in the pathogenesis of type 2 diabetes and its subtypes in blacks in the African Diaspora. However, environmental factors must also be considered as major contributors to the higher prevalence of type 2 diabetes and its subtypes in blacks in the African Diaspora. These multiple alterations should be targets for early prevention of type 2 diabetes in blacks in the African Diaspora.

Regional and overall aortic function in nondiabetic individuals with insulin resistance and normal glucose tolerance.

CONTEXT: Insulin resistance is associated with altered vascular function in diabetes. OBJECTIVE: The objective of the study was to define the overall and regional aortic function as well as the changes of aortic function over time in nondiabetic individuals with insulin resistance and a normal oral glucose tolerance test (OGTT). DESIGN: This was a cross-sectional and longitudinal analysis with 12 months follow-up. SETTING: The setting of the study was in primary care. PATIENTS: Nondiabetic individuals (n = 181, mean age 42 ± 8 y) with a normal OGTT and insulin resistance as defined by the insulin sensitivity index (ISI) participated in the study. INTERVENTIONS: ISI was estimated from serial measurements of plasma insulin and glucose during an iv glucose tolerance test. Ascending and abdominal aortic distensibility (AoD) and stiffness index-ß (AoSI) were assessed using echocardiography. Carotid-to-femoral artery pulse wave velocity (PWVc-f; an index of overall aortic function) was measured from carotid and femoral arteries Doppler flow velocities recorded simultaneously with an electrocardiogram. Associations between ISI, AoD, AoSI, and PWVc-f were assessed using linear regression analyses and ANOVA. Differences between baseline and 12 months were compared using a paired t test. MAIN OUTCOME MEASURES: AoD and AoSI associations as well as changes over a 12-month period in relation to ISI were measured. RESULTS: Ascending AoD (P = .01) and ascending AoSI (P = .025) were significantly associated with ISI; in contrast, abdominal AoD and AoSI and PWVc-f did not. Changes in AoD, AoSI, and PWVc-f over time were more prominent in individuals with low ISI compared with those with high ISI. CONCLUSIONS: The significant associations between ISI and aortic function suggest that insulin resistance may affect the cardiovascular system, even when OGTT is normal.

Characterization of metabolically unhealthy overweight/obese African American women: significance of insulin-sensitive and insulin-resistant phenotypes.

BACKGROUND: Obesity is often associated with high cardiovascular disease risk factors. Obesity is common in African American women. We investigated the characteristics of metabolically healthy and metabolically unhealthy overweight/obese African American women based on the presence of insulin resistance. MATERIALS/METHODS: We studied 196 apparently healthy overweight/obese African American women with family history of type 2 diabetes. Waist circumference, fasting glucose, insulin, c-peptide, lipids and lipoproteins, and systolic and diastolic blood pressure were obtained in each subject. In addition, insulin sensitivity was calculated using Bergman's Minimal Model Method. We defined insulin-sensitive metabolically healthy African American women as individuals with insulin sensitivity greater than 2.7 x 10(-4) x min(-1) (uU/ mL)(-1) and insulin resistant, metabolically unhealthy as insulin sensitivity less than 2.7 x 10(-4) x min(-1) (uU/mL)(-1). RESULTS: Thirty-three percent of our subjects were metabolically healthy African American women, while 67% were metabolically unhealthy African American women. The metabolically healthy subjects were significantly younger and less obese than the metabolically unhealthy subgroup. Mean fasting serum glucose, insulin, and c-peptide were significantly lower (P = .001) in the metabolically healthy than in metabolically unhealthy subjects. However, the mean blood pressures were within normal in both subgroups. Mean serum cholesterol (p < .05) and triglyceride (p < .001) levels were significantly lower, whereas high-density lipoprotein cholesterol (p < .03) was significantly higher in the metabolically healthy than in the metabolically unhealthy subjects. We found 25.5% of our subjects had metabolic syndrome (30.3% metabolically unhealthy and 15.6% metabolically healthy). CONCLUSION: We concluded that: (1) despite obesity, metabolically healthy African American women appear to be less prone to type 2 diabetes and cardiovascular disease and (2) in view of the higher prevalence of metabolic syndrome, metabolically unhealthy African American women should be targeted for primary prevention of type 2 diabetes and cardiovascular disease.

Importance of aerobic fitness in cardiovascular risks in sedentary overweight and obese African-American women.

BACKGROUND: Whether the level of aerobic fitness significantly impacts cardiovascular disease (CVD) risks in healthy, nondiabetic, overweight or obese African-American women remains uncertain. OBJECTIVE: To examine the clinical and metabolic risk factors of CVD in nondiabetic, sedentary overweight or obese African-American women with varying degrees of aerobic fitness. METHODS: Forty-eight African-American women, with mean age of 43 +/- 4.2 years and body mass index of 32.3 +/- 3.6 kg/m2, participated in the study. Fasting and 2-hr postprandial serum glucose, insulin, and C-peptide levels were obtained during oral glucose tolerance test. Insulin sensitivity was calculated by Homeostasis Model Assessment (HOMA-IR). Aerobic fitness was categorized empirically as very low aerobic fitness (VLAF; n = 17, VO2max < 21 ml/kg/min), low aerobic fitness (LAF; n = 12, between 21 and 24.4 ml/kg/min), and moderate aerobic fitness (MAF; n = 19, >24.4 ml/kg/min). RESULTS: Significant differences were found in serum glucose, insulin, and C-peptide levels, and HOMA-IR in the VLAF vs. LAF and MAF groups. Mean HOMA-IR was statistically greater in the VLAF and LAF when compared to MAF. Mean fasting serum cholesterol, triglycerides, and low-density lipoprotein cholesterol levels were higher in the VLAF group compared to the MAF group, whereas high-density lipoprotein cholesterol was lower in the VLAF group. Despite differences in the obesity indices and insulin resistance in the three groups, the atherogenic lipids and lipoproteins were within normal limits, irrespective of degree of VO2max. DISCUSSION: Modest aerobic fitness has significant impact on insulin sensitivity and atherogenic lipids and lipoprotein parameters and the overall risks for CVD in sedentary overweight or obese African-American women. Whether modest physical fitness translates into prevention of type 2 diabetes and CVD in African-American women remains to be determined.