Creation of Plasma Free Amino Acid (PFAA) Index for Evaluating Visceral Fat Area and Cross-sectional/longitudinal Investigation of Association of PFAA Index with Lifestyle-related Diseases

Abstract

Objective: Plasma free amino acid (PFAA) profiles are reported to be associated with lifestyle-related diseases. We created a PFAA index for evaluating the visceral fat area (VFA), and investigated whether the index was associated with lifestyle-related diseases cross-sectionally and longitudinally.
Methods: Blood samples were taken from all subjects after an overnight fast. PFAA concentrations were measured by LC-MS. First, PFAA indexes for VFA were derived and validated using the PFAA concentrations and VFAs of 865 subjects who underwent abdominal CT examinations. Next, using the data of 215 subjects, we determined whether PFAA indexes were associated with number of metabolic syndrome risk factors. Finally, based on the baseline PFAA indexes in a cohort of 4,293 subjects investigated from 2008 to 2012, we calculated odds ratios for development of lifestyle-related diseases within four years using logistic regression analysis.
Results: The correlation coefficient for the relationship of PFAA index and VFA was 0.62 (p<0.0001). PFAA indexes and number of metabolic syndrome risk factors were significantly associated (p<0.001) by the Jonckheere trend test. When baseline PFAA indexes were categorized into three groups ('low', 'mid', 'high'), the odds ratio regarding development of lifestyle-related diseases for 'high' was significantly greater than that for 'low', after adjusting for age and gender.
Conclusion: Our findings suggested that the PFAA index was correlated with VFA and would be useful for evaluating the cross-sectional and longitudinal risk of lifestyle-related diseases.