Biological sources of variation of serum adiponectin among healthy individuals in comparison with related nutritional and inflammatory markers

Background Serum adiponectin (AN) is a nutritional and inflammatory marker of various diseases. Its biological sources of variation (SVs) have been widely evaluated, but its relationships with other related markers remain to be studied comprehensibly by use of multivariate analyses including factor analysis. Methods: Serum specimens from 752 well-defined healthy subjects (295 males; 457 females) obtained from Japan, Hong Kong, Taiwan, and Vietnam were tested for total AN (tAN) and high-molecular-weight AN (hmAN) together with 71 major analytes. We chose test results of 11 analytes known as nutritional and inflammatory markers: insulin, HDL-C, LDL-C, TG, ALT, GGT, UA, TTR, CRP, C3, and C4. Factor analysis (FA) was performed to elucidate commonality among the analytes. Multiple regression analysis (MRA) was performed analyte by analyte to evaluate its biological SVs including age, BMI, and levels of alcohol consumption, smoking, and exercise. Results: Both serum ANs showed female predominance, reduction with increased BMI, and regional difference (lower in Southeast Asia). The ratio of hmAN to tAN was higher in females. MRA showed no clear associations of tAN or hmAN with the levels of drinking alcohol or cigarette smoking. FA revealed that both tAN and hmAN have a commonality in biological variations with HDL-C, TG, CRP, and insulin but not with ALT, GGT, and TTR. Conclusions: No apparent differences were observed between tAN and hmAN with regard to commonality or association with related analytes by FA or MRA. It appears not necessary to distinguish hmAN from tAN when interpreting test results among healthy individuals.