Japanese men have larger areas of visceral adipose tissue than Caucasian men in the same levels of waist circumference in a population-based study

Abstract

Visceral adipose tissue (VAT) is an independent risk factor for metabolic and cardiovascular disorders. There has been no study that demonstrated different abdominal fat distribution between Asian and Caucasian men. As the Japanese are less obese but more susceptible to metabolic disorders than Caucasians, they may have larger VAT than Caucasians at similar levels of obesity. We compared the abdominal fat distribution of the Japanese (n ¼ 239) and Caucasian-American (n ¼ 177) men aged 40-49 years in groups stratified by waist circumference in a population-based sample. We obtained computed tomography images and determined areas of VAT and subcutaneous adipose tissue (SAT). We calculated VAT to SAT ratio (VSR). The Japanese men had a larger VAT and VSR in each stratum, despite substantially less obesity overall. In multiethnic studies, difference in abdominal fat distribution should be considered in exploring factors related to obesity. International Journal of Obesity (2006) In these studies, VAT was compared after adjusting for other factors such as age and obesity. There has been no report directly comparing VAT between the Japanese and Caucasian men in a population-based sample. Therefore, we compared the abdominal fat distribution of the Japanese and Caucasian-American men aged 40-49 years in groups stratified by waist circumference in a population-based sample. We recruited 240 American men aged 40-49 years (Caucasians: 82%), randomly selected from Allegheny County, Pennsylvania, US, and 240 Japanese men aged 40-49 years, randomly selected from Kusatsu, Shiga, Japan. We confined our analyses to Caucasian and Japanese men, because African men have been compared with Caucasians elsewhere, 6 and we had only one man who categorized himself as neither Caucasian nor African-American. In order to compare the abdominal adipose tissue (AAT) distribution at similar levels of waist circumference, participants with extremely large or small waist circumference (beyond the levels of mean 72 (s.d.)) were excluded from the present analysis. After excluding 44 non-Caucasian-Americans and 20 outliers in waist circumference, 416 (239 Japanese and 177 Caucasian) men were examined. Waist circumference

Visceral fat amount is associated with carotid atherosclerosis even in type 2 diabetic men with a normal waist circumference

“…Several studies suggest that Asians are more prone to visceral fat accumulation for a given waist circumference than Caucasian. 27,28 Accordingly, our results may differ from those in other ethnic groups. To definitely validate the need for the additional measure of quantifying visceral fat accumulation, well-controlled, prospective studies are warranted.…”

Visceral adiposity, not abdominal subcutaneous fat area, is associated with high blood pressure in Japanese men: the Ohtori study

“…Asians and Asian Americans have been reported to have a lower prevalence of obesity by body mass index compared with Caucasians or African Americans but have greater visceral adiposity at the same body mass index or waist circumference level as Caucasians or African Americans. [19][20][21]32,33 In this study, ASFA was not associated with an increased odds of the prevalence of hypertension in the models that included both IAFA and insulin resistance. This finding was consistent with previous reports in Japanese Americans.…”

Cardiac production of B-type natriuretic peptide is inversely related to the plasma level of free fatty acids in obese individuals - possible involvement of the insulin resistance -

“…Thus, the results of this study may not be applicable to those with the excluded disorders, particularly those with heart failure overt. Fourth, the study subjects were limited to Japanese and it is known that Asians have more severe metabolic syndrome at lower BMI compared to Caucasians [44,45]. Thus, the results of this study may not be generalizable to other populations.…”