Relation of dietary and other lifestyle traits to difference in serum adiponectin concentration of Japanese in Japan and Hawaii: The INTERLIPID Study

Background: In initial analyses, we found significant differences between serum adiponectin in Japanese living in Japan and Hawaii. Objective: We investigated whether differences in dietary and other lifestyle factors explain higher serum adiponectin concentrations in Japanese in Japan compared with Japanese emigrants living a Western lifestyle in Hawaii. Design: Serum adiponectin and nutrient intakes were examined by standardized methods in men and women aged 40-59 y from 2 population samples, one Japanese American in Hawaii (99 men, 104 women), the other Japanese in central Japan (124 men, 125 women). Multiple linear regression models were used to assess the role of dietary and other lifestyle traits in accounting for serum adiponectin difference between Hawaii and Japan. Results: Mean adiponectin was significantly higher in Japan than in Hawaii (10.5 ± 5.5 μg/mL compared with 6.7 ± 3.2 μg/mL in men, P = 0.002; 12.9 ± 5.9 μg/mL compared with 9.4 ± 4.2 in women, P < 0.0001). In men, the difference in body mass index (BMI; in kg/m²) in the 2 populations explained ≈90% of the difference in serum adiponectin; in women, only 29%. In multiple linear regression analyses in women further adjustment for physical activity and 4 nutrients (nonvegetable protein, n-3 polyunsaturated fatty acid, arachidonic acid, dietary cholesterol) produced a further reduction in the coefficient for the difference (total 56%); P value for the difference became 0.074. Conclusions: The significantly higher mean serum adiponectin concentration in Japan than in Hawaii may be attributable largely to differences in BMI. Differences in nutrient intake in the 2 samples were associated with only modest relation to the adiponectin difference.