Purpose: Low serum amylase activity and copy number (CN) variation (CNV) of the salivary amylase gene (AMY1 ) are reportedly associated with obesity and abnormal glucose metabolism; however, this association remains controversial. We aimed to clarify the relationship between serum amylase activity and the CNV of AMY1/2A/2B  with the occurrence of metabolic syndrome (MetS) in Chinese adults.
Patients and Methods: Anthropometry, metabolic risk factors, and serum amylase activity were assessed in 560 subjects (260 MetS patients; 300 healthy controls). AMY1/2A/2B  CNs were evaluated using the highly sensitive droplet digital PCR.
Results: The serum total, pancreatic, and salivary amylase activity, but not the AMY1/2A/2B  CNs, was significantly lower in MetS patients than that in the control subjects. Patients < 45 y had a lower AMY1  CN, compared to that in healthy controls. Low serum amylase activity was significantly associated with high MetS prevalence (p < 0.001). In the receiver operating characteristic curve analysis, serum amylase activity was a significant diagnostic indicator for MetS. The diagnostic value of total amylase was second only to that of γ-glutamyl transpeptidase; it was higher than that of alanine aminotransferase and uric acid.
Conclusion: Low serum amylase activity was significantly associated with increased risk of MetS in Chinese adults. Therefore, amylase could be a potential biomarker for predicting MetS.
Keywords: amylase, copy number variation, metabolic disorders, biomarker, Chinese population