South Asians have a high prevalence of type 2 diabetes, even at a lower BMI. This review sets out our perspective and hypothesis on the reasons for this. Emerging data from epidemiological studies indicate that South Asians may have a lower ability to secrete insulin, and thus may have less compensatory reserves when challenged with unhealthy lifestyles. Thus, insulin resistance may not be the primary driver of type 2 diabetes in this population. Furthermore, data also suggest that South Asians, on average, have lower muscle mass, and may have a specific propensity to ectopic hepatic fat accumulation and for intramyocellular fat deposition, which cause further disruption in insulin action. We hypothesise that the high diabetes susceptibility in South Asians is evolutionarily set through dual parallel and/or interacting mechanisms: reduced beta cell function and impaired insulin action owing to low lean mass, which is further accentuated by ectopic fat deposition in the liver and muscle. These areas warrant further research.

Aims

We assessed the relative associations of β-cell dysfunction and insulin sensitivity with baseline glycemic status and incident glycemic progression among Asian Indians in the United States.

Methods

A 5-sample oral glucose tolerance test was obtained at baseline. Normoglycemia, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and type 2 diabetes (T2DM) were defined by ADA criteria. The Matsuda Index (ISIM) estimated insulin sensitivity, and the Disposition Index (DIo) estimated β-cell function. Visceral fat was measured by abdominal CT. After 2.5years, participants underwent a 2-sample oral glucose tolerance test. Standardized polytomous logistic regression was used to examine associations with prevalent and incident glycemia.

Results

Mean age was 57±8years and BMI 26.1±4.6kg/m(2). Log ISIM and log DIo were associated with prediabetes and T2DM after adjusting for age, sex, BMI, family history of diabetes, hypertension, and smoking. After adjusting for visceral fat, only DIo remained associated with prediabetes (OR per SD 0.17, 95% CI: 0.70, 0.41) and T2DM (OR 0.003, 95% CI: 0.0001, 0.03). Incidence rates (per 1,000 person-years) were: normoglycemia to IGT: 82.0, 95% CI (40, 150); to IFG: 8.4, 95% CI (0, 41); to T2DM: 8.6, 95% CI (0, 42); IGT to T2DM: 55.0, 95% CI (17, 132); IFG to T2DM: 64.0, 95% CI (3, 316). The interaction between sex and the change in waist circumference (OR 1.8, per SD 95% CI: 1.22, 2.70) and the change in log HOMA-β (OR 0.37, per SD 95% CI: 0.17, 0.81) were associated with glycemic progression.

Conclusions

The association of DIo with baseline glycemia after accounting for visceral fat as well as the association of the change in log HOMA-β with incident glycemic progression implies innate β-cell susceptibility in Asian Indians for glucose intolerance or dysglycemia.

Introduction

South Asians have a high prevalence of type 2 diabetes mellitus (T2DM). This may be associated with high rates of conversion through the natural history of disease. However, there is a paucity of data on prediabetes and T2DM incidence and related predictors in South Asians in the USA.

Research design and methods

We estimated prediabetes and T2DM incidence after 5 years of follow-up in the Mediators of Atherosclerosis in South Asians Living in America study (n=481) and examined the associated correlates. We defined T2DM and prediabetes using the American Diabetes Association criteria. Prediabetes included isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT) and combined IFG and IGT.

Results

Overall, 152 (32%, 95% CI: 27.6 to 35.9) individuals progressed either from normal glucose tolerance to prediabetes or T2DM, or from prediabetes to T2DM. In standardised logistic regression models controlling for age and sex, only hepatic fat attenuation (increased hepatic fat) (OR: 0.67 (95% CI: 0.55 to 0.87) per SD, visceral fat area (OR: 1.36 (95% CI: 1.06 to 1.74) per SD and hypertension (OR: 2.21 (95% CI: 1.44 to 3.40) were associated with any glycemic progression.

Conclusions

South Asians in the USA have a high incidence of dysglycemia. Hepatic and visceral fat may be factors in glycemic progression, and prevention efforts should target ectopic fat reduction.

Objective

To examine the association between physician-reported percent of total compensation from salary and quality of diabetes care.

Design

Cross-sectional analysis.

Participants

Physicians (n = 1248) and their patients with diabetes mellitus (n = 4200) enrolled in 10 managed care plans.

Measurements

We examined the associations between physician-reported percent compensation from salary and processes of care including receipt of dilated eye exams and foot exams, advice to take aspirin, influenza immunizations, and assessments of glycemic control, proteinuria, and lipid profile, intermediate outcomes such as adequate control of hemoglobin A1c, lipid levels, and systolic blood pressure levels, and satisfaction with provider communication and perceived difficulty getting needed care. We used hierarchical logistic regression models to adjust for clustering at the health plan and physician levels, as well as for physician and patient covariates. We adjusted for plan as a fixed effect, meaning we estimated variation between physicians using the variance within a particular health plan only, to minimize confounding by other unmeasured health plan variables.

Results

In unadjusted analyses, patients of physicians who reported higher percent compensation from salary (>90%) were more likely to receive 5 of 7 diabetes process measures and more intensive lipid management and to have an HbA1c<8.0% than patients of physicians who reported lower percent compensation from salary (<10%). However, these associations did not persist after adjustment.

Conclusions

Our findings suggest that salary, as opposed to fee-for-service compensation, is not independently associated with diabetes processes and intermediate outcomes.

Background

The relationship between body weight and cardiometabolic disease may vary substantially by race/ethnicity.

Objective

To determine the prevalence and correlates of the phenotype of metabolic abnormality but normal weight (MAN) for 5 racial/ethnic groups.

Design

Cross-sectional analysis.

Setting

2 community-based cohorts.

Participants

2622 white, 803 Chinese American, 1893 African American, and 1496 Hispanic persons from MESA (Multi-Ethnic Study of Atherosclerosis) and 803 South Asian participants in the MASALA (Mediators of Atherosclerosis in South Asians Living in America) study.

Measurements

Prevalence of 2 or more cardiometabolic abnormalities (high fasting glucose, low high-density lipoprotein cholesterol, and high triglyceride levels and hypertension) among normal-weight participants was estimated. Correlates of MAN were assessed by using log-binomial models.

Results

Among normal-weight participants (n = 846 whites, 323 Chinese Americans, 334 African Americans, 252 Hispanics, and 195 South Asians), the prevalence of MAN was 21.0% (95% CI, 18.4% to 23.9%) in whites, 32.2% (CI, 27.3% to 37.4%) in Chinese Americans, 31.1% (CI, 26.3% to 36.3%) in African Americans, 38.5% (CI, 32.6% to 44.6%) in Hispanics, and 43.6% (CI, 36.8% to 50.6%) in South Asians. Adjustment for demographic, behavioral, and ectopic body fat measures did not explain racial/ethnic differences. After adjustment for age, sex, and race/ethnicity-body mass index (BMI) interaction, for the equivalent MAN prevalence at a BMI of 25.0 kg/m2 in whites, the corresponding BMI values were 22.9 kg/m2 (CI, 19.5 to 26.3 kg/m2) in African Americans, 21.5 kg/m2 (CI, 18.5 to 24.5 kg/m2) in Hispanics, 20.9 kg/m2 (CI, 19.7 to 22.1 kg/m2) in Chinese Americans, and 19.6 kg/m2 (CI, 17.2 to 22.0 kg/m2) in South Asians.

Limitation

Cross-sectional study design and lack of harmonized dietary data between studies.

Conclusion

Compared with whites, all racial/ethnic minority groups had a statistically significantly higher prevalence of MAN, which was not explained by demographic, behavioral, or ectopic fat measures. Using a BMI criterion for overweight to screen for cardiometabolic risk may result in a large proportion of racial/ethnic minority groups being overlooked.

Primary funding source

National Institutes of Health.

BACKGROUND: Drinking-water salinity has been associated with high blood pressure (BP) among communities in south-west coastal Bangladesh. We evaluated whether access to water from managed aquifer recharge (MAR)-a hydrogeological intervention to lower groundwater salinity by infiltrating rainwater into the aquifers-can reduce community BP. METHODS: We conducted a stepped-wedge cluster-randomized trial with five monthly visits between December 2016 and April 2017 in 16 communities. At each visit following baseline, four communities were randomized to access MAR water. Systolic BP was the primary outcome, measured during each visit using Omron® HEM-907 devices. We also measured participants 24-hour urinary sodium and households drinking- and cooking-water salinity each visit. We used multilevel regression models to estimate the effects of MAR-water access on participants BP. The primary analysis was intention-to-treat. RESULTS: In total, 2911 person-visits were conducted in communities randomized to have MAR-water access and 2834 in communities without MAR-water access. Households without MAR-water access predominantly used low-salinity pond water and 42% (range: 26-50% across visits) of households exclusively consumed MAR water when access was provided. Communities randomized to MAR-water access had 10.34 [95% confidence interval (CI): 1.11, 19.58] mmol/day higher mean urinary sodium, 1.96 (95% CI: 0.66, 3.26; p = 0.004) mmHg higher mean systolic BP and 1.44 (95% CI: 0.40, 2.48; p = 0.007) mmHg higher mean diastolic BP than communities without MAR-water access. CONCLUSIONS: Our findings do not support the scale-up of MAR systems as a routine drinking-water source, since communities that shifted to MAR water from the lower-salinity pond-water source had higher urinary sodium and BP.

Objective

To examine the association between physicians' reimbursement perceptions and outpatient test performance among patients with diabetes mellitus.

Study design

Cross-sectional analysis.

Methods

Participants were physicians (n = 766) and their managed care patients with diabetes mellitus (n = 2758) enrolled in 6 plans in 2003. Procedures measured included electrocardiography, radiography or x-ray films, urine microalbumin levels, glycosylated hemoglobin levels, and Pap smears for women. Hierarchical logistic regression models were adjusted for health plan and physician-level clustering and for physician and patient covariates. To minimize confounding by unmeasured health plan variables, we adjusted for health plan as a fixed effect. Therefore, we estimated variation between physicians using only the variance within health plans.

Results

Patients of physicians who reported reimbursement for electrocardiography were more likely to undergo electrocardiography than patients of physicians who did not perceive reimbursement (unadjusted mean difference, 4.9%; 95% confidence interval, 1.1%-8.9%; and adjusted mean difference, 3.9%; 95% confidence interval, 0.2%-7.8%). For the other tests examined, no significant differences in procedure performance were found between patients of physicians who perceived reimbursement and patients of physicians who did not perceive reimbursement.

Conclusions

Reimbursement perception was associated with electrocardiography but not with other commonly performed outpatient procedures. Future research should investigate how associations change with perceived amount of reimbursement and their interactions with other influences on test-ordering behavior such as perceived appropriateness.

Objective

To examine the association between the organizational model and diabetes processes of care.

Research design and methods

We used data from the Translating Research into Action for Diabetes (TRIAD), a multicenter study of diabetes care in managed care, including 8354 patients with diabetes. We identified five model types: for-profit group/network, for-profit independent practice association (IPA), nonprofit group/network, nonprofit IPA, and nonprofit group/staff. Process measures included retinal, renal, foot, lipid, and HbA(1c) testing; aspirin recommendations; influenza vaccination; and a sum of these seven processes of care over 1 year. Hierarchical regression models were constructed for each process measure and accounted for clustering at the health plan and provider group levels and adjusted for participant age, sex, race, ethnicity, diabetes treatment and duration, education, income, health status, and survey language.

Results

Participant membership in the model types ranged from 9% in nonprofit IPA models to 38% in nonprofit group/staff models. Over 75% of participants received most of the processes of care, regardless of model type. However, among for-profit plans, group/network models provided on average more processes of care than IPA models (5.5 vs. 4.7, P < 0.0001), and group/network models generally increased the probability of receiving a process by >or=10 percentage points. Among nonprofit plans, no effect of model type was found.

Conclusions

Among for-profit plans, group/network models provided better diabetes processes of care than IPA models. Although reasons are speculative, this may be due to the clinical infrastructure available in group models that is not available in IPA models.