News & Views interviewed Wen-Chih “Hank” Wu, MD, MPH, last fall about the diversity of Asian-American subgroups and, in broad strokes, the implications for their care as it relates to obesity and cardiovascular health. Here, in Part II of a three-part series, the focus narrows to South Asians and the burden of type 2 diabetes in this population.
By Ana Mola, PhD, RN, ANP-BC, MAACVPR, with Hank Wu, MD, MPH
South Asians (SA) constitute approximately 1.6 billion people from the Indian subcontinent and make up the largest diaspora globally. They hail from different countries – Bangladesh, Bhutan, India, Nepal, Pakistan and Sri Lanka – but one of the many commonalities they share is this: their inordinate risk, compared with people of European ancestry, for type 2 diabetes and associated complications of the heart, kidneys and eyes.
As a healthcare professional, you might be surprised to learn that, based on the unique health characteristics of SA, you may not be applying the best approach for gauging body fat composition and calibrating diabetes risk in these patients.
Current Knowledge
Several distinct features with respect to type 2 diabetes are present in SA people compared with other ethnic groups, including:
- earlier onset of disease and complications
- occurrence at a lower body mass index (BMI)
- increased levels of serum pro-inflammatory and pro-thrombotic factors
- higher degrees of endothelial dysfunction and β-cell dysfunction, with a reduced insulin secretion capacity that is disproportionate to the severity of insulin resistance and ectopic fat deposition.1,2
Importantly, this heightened risk of type 2 diabetes with the SA or Indian phenotype is strongly associated with a high body fat composition – but often within a normal body weight and BMI category according to Western standards.3,4,5 Despite no universal definition of the metabolic profile of the phenotype, it is commonly characterized by insulin resistance, hyperglycemia, low HDL cholesterol and high triglycerides within a normal body weight range.4
Considerations for Future Care
The scientific literature demonstrates a high percentage of body fat, and particularly a predominance of abdominal fat, as common in many SA. A better understanding of the contribution of compartments of body fat composition to health in this population across their lifespan is needed. Additionally, objective measurement of composition more relevant than the commonly used epidemiological measures and clinical indices – including BMI, waist circumference and skinfold thickness – needs to be consistently incorporated in clinical practice among the SA populations.
Waist-to-hip ratio. A study in newly diagnosed patients from India with type 2 diabetes and controls without diabetes showed that central obesity, as measured by waist-to-hip ratio (WHR), had a stronger association with glycemia than did BMI. Despite their lower BMI compared with the population of European ancestry, the SA phenotype is typified by a higher WHR.6 With this emerging scientific evidence over the past several years, it’s important to ask:
- Are clinicians consistently using the WHR in their daily practice when assessing the SA populations at risk for type 2 diabetes?
- Are clinicians using the standard BMI and obesity classification guidelines recommended in clinical practice for the SA population, which may identify SA at risk cardiometabolic conditions at lower BMI (overweight ≥ 23)?
The Takeaway
The rapid increase in the prevalence of type 2 diabetes in SA underscores the challenge facing policy makers, researchers, educators and clinicians with respect to prevention and management. The burden of the diabetes pandemic within the SA populations has important consequences for individuals, families and communities both locally and internationally as these populations immigrate to other countries, e.g. the United States. It’s not only about obesity phenotypes – but also lifestyles, acculturation, social drivers of health and healthcare disparities that impact diverse populations.
To learn more about obesity related to cardiometabolic risk and lifestyle among the diverse Asian populations in the United States, join Hank Wu, MD, MPH and Ana Mola, PhD, RN, ANP, MAACVPR, as they present “The Burden and Health Care Disparities of Obesity Among Asian American Populations” at AACVPR’s 38th Annual Meeting on Wednesday, September 13th.
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The Burden and Health Care Disparities of Obesity Among Asian American Populations
Presenters: Ana Mola, PhD, RN, ANP, MAACVPR; Hank Wu, MD, MPH
Background: Standard measures of obesity, (body weight and Body Mass Index), suggest that Asian American (AA) people have a lower prevalence than other racial groups in the United States. However, AA people (Chinese, Japanese, Korean and Southeast Asians) face a unique challenge in their pattern of adiposity with central obesity, which raises the risk for multiple comorbidities such as type 2 diabetes, metabolic syndrome and cardiovascular disease at lower BMI compared with other populations. Several organizations recommend lower BMI cutoffs for obesity in Asian people (BMI ≥25.0 or ≥27.5 kg/m2) instead of the standard ≥30.0 kg/m2. The risks of obesity and related comorbidities in this population are further influenced by diet, physical activity and self-perceived obesity related to body perceptions – all of which are compounded by access to race-specific obesity information and therapies. Asian-specific parameters for assessing obesity should become a standard expectation of clinical practice. Asian Americans should equally be offered subgroup-specific tailored interventions owing to the heterogeneity of this population. This presentation will describe the healthcare disparities of AA populations related to the prevalence of obesity and comorbidities and mortality, race-specific obesity criteria, physical activity and exercise, diet, acculturation, body perceptions of obesity and the role of cultural beliefs. The access to anti-obesity medications, surgery and rehabilitation will be explored with discussions focused on health equity among the AA populations.
Objectives:
- Understand how standard measures of obesity (body weight and BMI) impact the healthcare disparity faced by AA populations.
- Describe the influences of the AA populations’ lifestyle behaviors, self-perceived obesity body perceptions and access to race specific obesity treatment management as drivers of healthcare disparities within these groups.
- Analyze the health disparities learnings of the AA populations’ cardiovascular care by participating in breakout groups to further discuss and generate strategies to address these disparities.
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REFERENCES
1. Misra A, Khurana L. Obesity- related non- communicable diseases: South Asians vs White Caucasians. Int J Obes. 2011;35:167- 187.
2. Unnikrishnan R, Anjana RM, Mohan V. Diabetes mellitus and its complications in India. Nat Rev Endocrinol 2016; 12: 357–70.
3. Singh PN, Arthur KN, Orlich MJ, et al. Global epidemiology of obesity, vegetarian dietary patterns, and noncommunicable disease in Asian Indians. Am J Clin Nutr 2014; 100 (suppl 1): 359S–64S.
4. Anoop S, Misra A, Mani K, Pandey RM, Gulati S. Diabetes risk prediction model for non -obese Asian Indians residing in North India using cut -off values for pancreatic and intra -abdominal fat volume and liver span. J Diabetes 2016; 8: 729–31.
5. Unnikrishnan R, Anjana RM, Mohan V. Diabetes in south Asians: is the phenotype different? Diabetes 2014; 63: 53–55.
6. Sattar N, Gill JMR. Type 2 diabetes in migrant south Asians: mechanisms, mitigation, and management. Lancet Diabetes Endocrinol 2015; 3: 1004–16.