Is the "South Asian Phenotype" Unique to South Asians?: Comparing Cardiometabolic Risk Factors in the CARRS and NHANES Studies.
BACKGROUND
In the context of rising obesity in South Asia, it is unclear whether the "South Asian phenotype"(described as high glucose, low high-density lipoprotein cholesterol, and high triglycerides at normal ranges of body weight) continues to be disproportionately exhibited by contemporary South Asians relative to other race/ethnic groups.


OBJECTIVE
We assessed the distinctiveness of the South Asian cardiometabolic profile by comparing the prevalence of combined high glucose, high triglycerides, and low high-density lipoprotein cholesterol (combined dysglycemia and dyslipidemia) in resident South Asians with 4 race/ethnic groups in the United States (Asians, black persons, Hispanics, and white persons) overall and by body mass index (BMI) category.


METHODS
South Asian data were from the 2010 to 2011 Center for Cardiometabolic Risk Reduction in South Asia Study, representative of Chennai and New Delhi, India and Karachi, Pakistan. U.S. data were from the 2011 to 2012 National Health and Nutrition Examination Survey, representative of the U.S.


METHODS
Combined dysglycemia and dyslipidemia was defined as fasting blood glucose ≥126 mg/dl and triglyceride/high-density lipoprotein cholesterol ratio >4. Logistic regression was used to estimate the relative odds and 95% confidence intervals of combined dysglycemia and dyslipidemia associated with each race/ethnic group (referent, U.S. white persons). Models were estimated among adults aged 20 to 79 years by sex and BMI category and accounted for age, education, and tobacco use. Data from 8,448 resident South Asians, 274 U.S. Asians, 404 U.S. black persons, 308 U.S. Hispanics, and 703 U.S. white persons without previously known diabetes were analyzed.


RESULTS
In the normal body weight range of BMI 18.5 to 24.9 kg/m(2), the prevalence of combined dysglycemia and dyslipidemia among men and women, respectively, was 33% and 11% in resident South Asians, 15% and 1% in U.S. Asians, 5% and 2% in U.S. black persons, 11% and 2% in U.S. Hispanics, and 8% and 2% in U.S. white persons. Compared with U.S. whites persons, South Asians were more likely to present with combined dysglycemia and dyslipidemia at all categories of BMI for men and at BMI 18.5 to 29.9 for women in adjusted models. The most pronounced difference between South Asians and U.S. white persons was observed at normal weight (adjusted odds ratio: 4.98; 95% confidence interval: 2.46 to 10.07 for men) (adjusted odds ratio: 9.09; 95% confidence interval: 2.48 to 33.29 for women).


CONCLUSIONS
Between 8% and 15% of U.S. men and 1% and 2% of U.S. women of diverse race/ethnic backgrounds exhibited dysglycemia and dyslipidemia at levels of body weight considered "healthy," consistent with the cardiometabolic profile described as the "South Asian Phenotype." Urban South Asians, however, were 5 to 9 times more likely to exhibit dysglycemia and dyslipidemia in the "healthy" BMI range compared with any other U.S. race/ethnic group.
Centre for Control of Chronic Conditions, New Delhi, India; Global Diabetes Research Center, Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA. Electronic address: s.a.patel@emory.edu.
Shivani A
SA
Patel
Centre for Control of Chronic Conditions, New Delhi, India; Public Health Foundation of India, New Delhi, India; Centre for Chronic Disease Control, New Delhi, India.
Roopa
R
Shivashankar
Centre for Control of Chronic Conditions, New Delhi, India; Global Diabetes Research Center, Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
Mohammed K
MK
Ali
Department of Diabetology, Madras Diabetes Research Foundation, Chennai, India.
R M
RM
Anjana
Department of Diabetology, Madras Diabetes Research Foundation, Chennai, India; Department of Epidemiology, Madras Diabetes Research Foundation, Chennai, India.
M
M
Deepa
Centre for Control of Chronic Conditions, New Delhi, India; Centre for Chronic Disease Control, New Delhi, India.
Deksha
D
Kapoor
Centre for Control of Chronic Conditions, New Delhi, India; Public Health Foundation of India, New Delhi, India; Centre for Chronic Disease Control, New Delhi, India.
Dimple
D
Kondal
Centre for Control of Chronic Conditions, New Delhi, India; Public Health Foundation of India, New Delhi, India.
Garima
G
Rautela
Department of Diabetology, Madras Diabetes Research Foundation, Chennai, India.
V
V
Mohan
Centre for Control of Chronic Conditions, New Delhi, India; Global Diabetes Research Center, Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
K M Venkat
KM
Narayan
Aga Khan University, Karachi, Pakistan.
M Masood
MM
Kadir
Aga Khan University, Karachi, Pakistan.
Zafar
Z
Fatmi
Centre for Control of Chronic Conditions, New Delhi, India; Public Health Foundation of India, New Delhi, India; Centre for Chronic Disease Control, New Delhi, India.
Dorairaj
D
Prabhakaran
Centre for Control of Chronic Conditions, New Delhi, India; Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, New Delhi, India.
Nikhil
N
Tandon
D000328:Adult; D001741:Black or African American; D000368:Aged; D001213:Asian; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D008076:Cholesterol, HDL / Q000097:blood; D050171:Dyslipidemias / Q000097:blood / Q000208:ethnology*; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D006943:Hyperglycemia / Q000208:ethnology* / Q000378:metabolism; D015228:Hypertriglyceridemia / Q000097:blood / Q000208:ethnology*; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D010154:Pakistan / Q000453:epidemiology; D010641:Phenotype; D015995:Prevalence; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood; D014481:United States / Q000453:epidemiology; D044465:White People; D055815:Young Adult
D001786:Blood Glucose; D008076:Cholesterol, HDL; D014280:Triglycerides