Meghana D. Gadgil

Dietary Patterns Are Associated with Metabolic Risk Factors in South Asians Living in the United States

BACKGROUND South Asians are at high risk of metabolic syndrome, and dietary patterns may influence this risk. OBJECTIVES We aimed to determine prevalent dietary patterns for South Asians in the United States and their associations with risk factors for metabolic syndrome. METHODS South Asians aged 40-84 y without known cardiovascular disease were enrolled in a community-based cohort called Mediators of Atherosclerosis in South Asians Living in America. A validated food frequency questionnaire and serum samples for fasting and 2-h glucose, insulin, glycated hemoglobin, triglycerides, and total and HDL cholesterol were collected cross-sectionally. We used principal component analysis with varimax rotation to determine dietary patterns, and sequential linear and logistic regression models for associations with metabolic factors. RESULTS A total of 892 participants were included (47% women). We identified 3 major dietary patterns: animal protein; fried snacks, sweets, and high-fat dairy; and fruits, vegetables, nuts, and legumes. These were analyzed by tertile of factor score. The highest vs. the lowest tertile of the fried snacks, sweets, and high-fat dairy pattern was associated with higher homeostasis model assessment of insulin resistance (HOMA-IR) (β: 1.88 mmol/L ⋅ uIU/L) and lower HDL cholesterol (β: -4.48 mg/dL) in a model adjusted for age, sex, study site, and caloric intake (P < 0.05). The animal protein pattern was associated with higher body mass index (β: 0.73 m/kg(2)), waist circumference (β: 0.84 cm), total cholesterol (β: 8.16 mg/dL), and LDL cholesterol (β: 5.69 mg/dL) (all P < 0.05). The fruits, vegetables, nuts, and legumes pattern was associated with lower odds of hypertension (OR: 0.63) and metabolic syndrome (OR: 0.53), and lower HOMA-IR (β: 1.95 mmol/L ⋅ uIU/L) (P < 0.05). CONCLUSIONS The animal protein and the fried snacks, sweets, and high-fat dairy patterns were associated with adverse metabolic risk factors in South Asians in the United States, whereas the fruits, vegetables, nuts, and legumes pattern was linked with a decreased prevalence of hypertension and metabolic syndrome.

The Effects of Carbohydrate, Unsaturated Fat, and Protein Intake on Measures of Insulin Sensitivity Results from the OmniHeart Trial

OBJECTIVE Impaired insulin sensitivity increases the risk of cardiovascular disease. Although calorie restriction and weight loss increase insulin sensitivity, the effects of modifying macronutrient composition on insulin sensitivity are uncertain. The purpose of this study is to determine the effects on insulin sensitivity of a carbohydrate-rich diet (CARB; similar to the Dietary Approaches to Stop Hypertension [DASH] diet), a protein-rich diet (PROT; protein predominantly from plant sources), and an unsaturated fat–rich diet (UNSAT; predominantly monounsaturated). RESEARCH DESIGN AND METHODS This study was a randomized, controlled, three-period, crossover feeding study. The study participants were 164 individuals with prehypertension or stage 1 hypertension without diabetes. Diets were administered for 6 weeks each, with a washout period between diets of 2–4 weeks. Weight was held constant throughout the study. For our primary outcome, we calculated the quantitative insulin sensitivity check index (QUICKI) using the end-of-period fasting serum glucose and insulin. QUICKI is a validated measure of insulin sensitivity. The primary analyses used generalized estimating equations. RESULTS At baseline, mean (SD) BMI was 30.2 (6.1) kg/m2, and mean (SD) QUICKI was 0.35 (0.04). The UNSAT diet increased QUICKI by 0.005, more than the CARB diet (P = 0.04). PROT had no significant effect compared with CARB. CONCLUSIONS A diet that partially replaces carbohydrate with unsaturated fat may improve insulin sensitivity in a population at risk for cardiovascular disease. Given the well-recognized challenges of sustaining weight loss, our results suggest an alternative approach for improving insulin sensitivity.

Laboratory Testing for and Diagnosis of Nutritional Deficiencies in Pregnancy Before and After Bariatric Surgery

OBJECTIVE Bariatric surgery can reduce the risk of obesity-related complications of pregnancy, but may cause essential nutrient deficiencies. To assess adherence to laboratory testing guidelines, we examined frequency of testing for and diagnosis of deficiency during preconception and pregnancy using claims data in women with a delivery and bariatric surgery. METHODS Retrospective analysis of claims from seven Blue Cross/Blue Shield plans between 2002 and 2008. We included women with a delivery and bariatric surgery within the study period. We used common procedural terminology (CPT) and ICD-9 codes to define laboratory testing and deficiencies for iron, folate, vitamin B12, vitamin D, and thiamine. Using Students t-test and chi-square testing, we compared frequency of laboratory tests and diagnoses during 12 months preconception and 280 days of pregnancy between women with pregnancy before versus after surgery. We used multivariate logistic regression to evaluate for predictors of laboratory testing. RESULTS We identified 456 women with pregnancy after bariatric surgery and 338 before surgery. The frequency of testing for any deficiency was low (9%-51%), but higher in those with pregnancy after surgery (p<0.003). The most common deficiency was vitamin B12 (12%-13%) with pregnancy after surgery (p<0.006). Anemia and number of health provider visits were independent predictors of laboratory testing. CONCLUSION Women with pregnancy after bariatric surgery were tested for and diagnosed with micronutrient deficiencies more frequently than those with pregnancy before surgery. However, most laboratory testing occurred in less than half the women and was triggered by anemia. Increased testing may help identify nutrient deficiencies and prevent consequences for maternal and child health.

Dietary intakes among South Asian adults differ by length of residence in the USA.

OBJECTIVE To examine whether nutrient and food intakes among South Asian adult immigrants differ by length of residence in the USA. DESIGN Cross-sectional analysis to examine differences in nutrient and food intakes by length of residence in the USA. Dietary data were collected using an interviewer-administered, culturally appropriate FFQ, while self-reported length of residence was assessed using a questionnaire and modelled as tertiles. SETTING The Mediators of Atherosclerosis in South Asians Living in America (MASALA) study. SUBJECTS Eight hundred and seventy-four South Asians (mean age=55 (sd 9) years; 47 % women; range of length of residence in the USA=2-58 years), part of the baseline examination of the MASALA study. RESULTS Intakes of fat, including saturated and trans fats, dietary cholesterol and n-6 fatty acids, were directly associated with length of residence, while intakes of energy, carbohydrate, glycaemic index and load, protein, dietary fibre, folate and K were inversely associated with length of residence (P trend <0·05). A longer length of residence in the USA was also associated with higher intakes of alcoholic beverages, mixed dishes including pizza and pasta, fats and oils, and lower intakes of beans and lentils, breads, grains and flour products, milk and dairy products, rice, starchy vegetables and sugar, candy and jam (P for differences across groups <0·05). CONCLUSIONS Length of residence in the USA influences diet and nutrient intakes among South Asian adult immigrants and should be considered when investigating and planning dietary interventions to mitigate chronic disease risk.

Psychosocial Factors Associated with Subclinical Atherosclerosis in South Asians: The MASALA Study

Abstract South Asians have the highest rates of premature atherosclerotic cardiovascular disease amongst all ethnic groups in the world; however this risk cannot be fully explained by traditional risk factors. Participants from the Mediators of Atherosclerosis in South Asians Living in America Study were included in this cross-sectional analysis. The purpose of this study was to investigate the association of psychosocial factors (including anger, anxiety, depressive symptoms, current and chronic stress, and everyday hassles) with carotid intima-media thickness (CIMT). Three multivariate models were examined to evaluate the association between the psychosocial factors and CIMT. Findings suggest that the impact of psychosocial factors on subclinical atherosclerosis is differential for South Asian men and women. For men, anxiety and depression were associated; while for women, stress was associated with common carotid intima media thickness, independent of traditional CVD risk factors, diet and physical activity.

Type 2 diabetes after gestational diabetes mellitus in South Asian women in the United States

Gestational diabetes mellitus (GDM) is a major risk factor for type 2 diabetes. The incidence of both GDM and type 2 diabetes is exceedingly high in South Asian populations. However, the risk of type 2 diabetes after GDM in South Asian women in the United States is unknown.

Do static and dynamic insulin resistance indices perform similarly in predicting pre-diabetes and type 2 diabetes?

AIMS We designed a study to compare the predictive power of static and dynamic insulin resistance indices for categorized pre-diabetes (PDM)/type 2 diabetes (DM). METHODS Participants included 1134 adults aged 18-60 years old with normal glucose at baseline who completed both baseline and 6-years later follow-up surveys. Insulin resistance indices from baseline data were used to predict risk of PDM or DM at follow-up. Two static indices and two dynamic indices were calculated from oral glucose tolerance test results (OGTT) at baseline. Area under the receiver operating characteristic curve (AROC) analysis was used to estimate the predictive ability of candidate indices to predict PDM/DM. A general estimation equation (GEE) model was applied to assess the magnitude of association of each index at baseline with the risk of PDM/DM at follow-up. RESULTS The dynamic indices displayed the largest and statistically predictive AROC for PDM/DM diagnosed either by fasting glucose or by postprandial glucose. The bottom quartiles of the dynamic indices were associated with an elevated risk of PDM/DM vs. the top three quartiles. However, the static indices only performed significantly to PDM/DM diagnosed by fasting glucose. CONCLUSIONS Dynamic insulin resistance indices are stronger predictors of future PDM/DM than static indices. This may be because dynamic indices better reflect the full range of physiologic disturbances in PDM/DM.