Less favorable body composition and adipokines in South Asians compared with other US ethnic groups: results from the MASALA and MESA studies

Abstract

Background Small studies have shown that South Asians (SAs) have more total body, subcutaneous, visceral and hepatic fat and abnormal adipokine levels compared to Whites. However, comprehensive studies of body composition and adipokines in SAs compared to other ethnic groups are lacking. Methods Using harmonized data, we performed a cross-sectional analysis of two community-based cohorts: Mediators of Atherosclerosis of South Asians Living in America (MASALA, n=906) and Multi-Ethnic Study of Atherosclerosis (MESA which included 2,622 Whites; 803 Chinese Americans; 1,893 African Americans; and 1,496 Latinos). General linear models were developed to assess ethnic differences in ectopic fat (visceral, intermuscular, and pericardial fat; and hepatic attenuation), lean muscle mass, and adipokines (adiponectin and resistin). Models were adjusted for age, sex, site, alcohol use, smoking, exercise, education, household income and BMI. Ectopic fat models were additionally adjusted for hypertension, diabetes, HDL, and triglycerides. Adipokine models were adjusted for subcutaneous, visceral, intermuscular, and pericardial fat; and hepatic attenuation. Results Compared to all ethnic groups in MESA (Whites, Chinese Americans, African Americans, and Latinos), SAs had greater intermuscular fat (pairwise comparisons to each MESA group, p < 0.01), lower hepatic attenuation (p < 0.001), and less lean mass (p < 0.001). SAs had greater visceral fat compared to Chinese Americans, African Americans and Latinos (p < 0.05) and greater pericardial fat compared to African Americans (p < 0.001). SAs had lower adiponectin levels compared to other ethnic groups (p < 0.01; except Chinese Americans) and higher resistin levels than all groups (p < 0.001), even after adjusting for differences in body composition. Conclusion There are significant ethnic differences in ectopic fat, lean mass, and adipokines. A less favorable body composition and adipokine profile in South Asians may partially explain the increased predisposition to cardiometabolic disease. The mechanisms that underlie these differences warrant further investigation.

Cardiovascular health metrics among South Asian adults in the United States: Prevalence and associations with subclinical atherosclerosis

“…The low prevalence of ideal CVH metrics in US South Asians is similar to what has been found in the general US population Longitudinal follow-up of the MASALA cohort will allow further study of the relationship between the AHA CVH metrics and progression of subclinical atherosclerosis, incident CVD events, and mortality. Effective primordial and primary prevention interventions are needed to preserve and improve CVH in US South Asians, as well as continued research on novel and emerging risk factors (Bharmal et al, 2016; Flowers et al, 2015; Nadimpalli et al, 2016; A. D. Shah et al, 2016; B.…”

The Obesity Paradox in Cancer—Moving Beyond BMI

“… * BMI recorded from the all MASALA/MESA studies. Reprinted by permission from Macmillan Publishers Ltd: International Journal of Obesity (21), copyright 2016 …”

“…Of note, south Asians have almost ‘normal’ average BMI, but have a lower LBM and higher visceral fat than African Americans. (21) Age is another factor associated with alterations in body composition and with age there is a decrease in muscle mass and strength, known as sarcopenia. (22–24) The assumption that adults have an optimal weight range (corrected for height) is probably sound, but assuming that this is the same for all individuals regardless of ethnicity, age, and health status is challenging.…”

Associations Between Television Viewing and Adiposity Among South Asians

“…Pericardial fat volume (cm 3 ) and hepatic fat attenuation (Hounsfield Unit) were assessed by non-contrast cardiac CT. The detailed methods for anthropometry and fat area measurements are provided elsewhere [6, 11]. …”

“…South Asians have been shown to have a higher percentage of body fat than Caucasians and other Asian ethnic groups [5] and are also at higher risk of abdominal obesity which is a significant risk factor for insulin resistance [3, 6]. Sedentary behaviors, especially television (TV) viewing, have been found to be associated with weight gain, obesity, and higher risk of chronic diseases [7], and one of the reasons could be the reduction in physical activity among those with higher level of TV viewing[8,9].…”