International Comparison of Abdominal Fat Distribution Among Four Populations: The ERA-JUMP Study

Abstract

Background: Abdominal fat distribution varies across groups with different races or environments. Whether environmental factors, apart from racial differences, affect abdominal fat distribution is unknown.

Methods: We compared the abdominal fat distribution of four groups; different races with similar environments (Caucasians vs. Japanese Americans), different environments with an identical race (Japanese Americans vs. Japanese), and similar races with similar environments (Japanese vs. Koreans). A population-based sample of 1212 men aged 40-49 were analyzed: 307 Caucasians and 300 Japanese Americans in the United States, 310 Japanese in Japan, and 295 Koreans in Korea. We compared the proportion of visceral adipose tissue area to total abdominal adipose tissue area (VAT%) and other factors that can affect abdominal fat distribution (smoking, alcohol use, physical activity levels, and metabolic factors).

Results: VAT% was significantly higher in Japanese and Koreans than in Japanese Americans and Caucasians (50.0, 48.5, 43.2, 41.0%, respectively, P < 0.001). Even after adjustment for possible confounders, the significant VAT% difference remained in comparing groups with identical race but different environments (i.e., Japanese vs. Japanese Americans). In contrast, comparing groups with different races but similar environments (i.e., Caucasians vs. Japanese Americans), VAT% was not significantly different. Comparing groups with similar races and similar environments (i.e., Japanese vs. Koreans), VAT% did not significantly differ.

Conclusions: Environmental differences, apart from racial differences, affect the difference in abdominal fat distribution across different groups in middle-aged men.

Keywords: cross-sectional study; epidemiology; international study; subcutaneous adipose tissue; visceral adipose tissue.

FIG. 1.

Multivariable-adjusted mean values of VAT% among men with 24≤ body mass index <27 kg/m². Model I was adjusted for age, height, and waist circumference. Model II was adjusted for variables in model I plus smoking status (nonsmokers, exsmokers, smokers less than 20 cigarettes/day, or smokers 20 cigarettes or more/day), amount of alcohol intake (grams/day), and physical activity levels of the participants' current jobs (sedentary, light physical activity, medium physical activity, or very heavy). Model III was adjusted for variables in model II plus levels of systolic blood pressure, fasting blood glucose, triglycerides, and high-density lipoprotein cholesterol. P < 0.001 for overall comparison in all characteristics. For pairwise comparisons, *P < 0.05, and **P < 0.001. VAT%, proportion of VAT area to the sum of VAT and SAT areas.