Visceral Fat and Race-Dependent Health Risks in Obese Nondiabetic Premenopausal Women

Abstract

Our previous finding that a waist-to-hip ratio (WHR) >0.85 was not associated with similar health risks in black, compared with white, obese premenopausal non-diabetic women of similar fatness is attributed to either 1) a different relationship between WHR and visceral adiposity or 2) differences in the relationship between visceral adiposity and the metabolic abnormalities of obesity. We measured visceral (VAT) and subcutaneous adipose tissue (SCAT) areas at midwaist in 25 black and 25 white obese nondiabetic pre-menopausal women with similar BMI, percentage body fat, and wide range of WHR (0.7-0.95 for black women and 0.7-0.9 for white women) and then compared insulin sensitivity index (SI), glucose and insulin areas under the 2-h curve (AUCs) during an oral glucose tolerance test (OGTT), and blood lipids in the two groups before and after adjustments for total body and visceral adiposity. After adjusting for total body fat mass (FM), obese black women had significantly less VAT (by 32 cm2) and lower VAT/SCAT for any given WHR. The regression equations predicting the SI the glucose and insulin AUCs, and the triglyceride and HDL cholesterol levels from regional adipose tissue measurements (VAT, SCAT, or VAT/SCAT) and from total body fat (FM or percentage body fat) had slopes that were not significantly different for black and white women. LDL cholesterol levels were independently related to VAT in black but not in white women. The black women had a similar SI insulin AUC, and triglyceride levels but significantly lower glucose AUC and higher HDL cholesterol levels (P < 0.001), after adjusting for VAT and FM. Regression analysis of the pooled data showed that high VAT and high VAT/SCAT, but not SCAT, predicted lower SI higher glucose and insulin AUCs during OGTT, and higher triglyceride levels, independent of total adiposity. We conclude that while increases in VAT and VAT/SCAT adversely affect metabolism in both black and white obese premenopausal women, similar levels of total body and visceral adiposity are associated with different metabolic risk factors in these groups.

Low subcutaneous thigh fat is a risk factor for unfavourable glucose and lipid levels, independently of high abdominal fat. The Health ABC Study

“…Black persons have generally less visceral fat compared with white persons, whereas the subcutaneous fat (either abdominal or at the thigh) is higher, for any level of total body fat. Black people had a better lipid profile in our data, which has also been found previously [36,37]. It has been shown that in both sexes black persons have higher LPL activity and lower HL activity compared with white persons [36], which may explain these differences in lipid profile and fat distribution.…”

Metabolic Syndrome in Blacks: Are the Criteria Right?

“…However, this concept or hypothesis is more applicable and relevant in several non-black populations, but remains controversial in blacks. For identical BMI, recent studies showed that black adults and youth residing in diverse geographic locations have lower visceral adiposity despite increased insulin resistance when compared with whites [44][45][46][47].…”

“…In blacks, WC is the most common component of MetS [11, 14-16••, 18]. WC serves as a surrogate for intraabdominal visceral adipose tissue (VAT) and an important determinant of insulin resistance and its concomitants for CVD in non-black populations [44][45][46][47]. However, this concept or hypothesis is more applicable and relevant in several non-black populations, but remains controversial in blacks.…”

Adipose Tissue Dysfunction in Polycystic Ovary Syndrome

“…In addition to greater degrees of overall obesity, women with PCOS may be more likely to exhibit an abdominal and/or visceral pattern of fat distribution [10]. Because these depots are associated with a more adverse metabolic profile, including greater degrees of insulin resistance and glucose intolerance [11], the distribution of fat to abdominal/visceral sites has been offered as one explanation for the metabolic abnormalities observed in PCOS [10]. Nevertheless, there are many women with PCOS who are not overtly obese, yet are insulin resistant.…”