Levels of adiponectin are inversely associated with obesity levels. We examined the levels of adiponectin in American (n = 98) and Japanese (n = 92) men aged 40 to 49 years. Contrary to our expectations, the American men had higher levels of adiponectin than the Japanese men (13.3 +/- 5.8 vs 7.3 +/- 4.2 (microg/mL) despite higher levels of obesity. Smaller areas of visceral adipose tissue in American than in Japanese men may have resulted in the higher levels of adiponectin.