title: Association between salivary amylase (AMY1) gene copy numbers and insulin resistance in asymptomatic Korean men.
abstract: OBJECTIVE
  Salivary amylase gene (AMY1) copy number variations (CNVs) correlate directly with salivary amylase activity and serum amylase levels. Previously, individuals with high AMY1 CNVs exhibited low postprandial glucose levels and postprandial early insulin surge, suggesting that high AMY1 gene copy numbers may play a role in lowering the risk of insulin resistance.
  
  
  METHODS
  We verified the relationship between AMY1 CNVs and homeostatic model assessment-insulin resistance (HOMA-IR) in a cohort of 1257 Korean men aged 20-65 years who visited two medical centres for regular health check-ups, and in subgroups of current smokers and regular alcohol drinkers. Individuals with fasting plasma glucose levels > 10.0 mmol/l, HbA1c ≥ 64 mmol/mol (8.0%) or who used oral hypoglycaemic agents or insulin were excluded.
  
  
  RESULTS
  AMY1 CNVs correlated negatively with HOMA-IR even after adjusting for covariates (e.g. BMI, systolic blood pressure, triacylglycerol, alcohol consumption, smoking and physical activity). When the participants were divided according to current smoking and alcohol consumption habits, negative correlations between AMY1 CNVs and HOMA-IR were more evident among non-smokers and regular drinkers and were non-significant among smokers and non-regular drinkers.
  
  
  CONCLUSIONS
  Low AMY1 CNVs correlated with high insulin resistance in asymptomatic Korean men, and such a relationship presented differently according to the status of smoking and alcohol consumption.
authors.affiliation: Department of Family Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Family Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Y-S
authors.initials: YS
authors.lastname: Nam
authors.affiliation: Department of Family Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: J M
authors.initials: JM
authors.lastname: Yun
authors.affiliation: Department of Family Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Family Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: B L
authors.initials: BL
authors.lastname: Cho
authors.affiliation: Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: H-Y
authors.initials: HY
authors.lastname: Son
authors.affiliation: Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: J I
authors.initials: JI
authors.lastname: Kim
authors.affiliation: Samsung Genome Institute, Samsung Medical Center, Seoul, Korea.
authors.forename: J W
authors.initials: JW
authors.lastname: Yun
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D015331:Cohort Studies; D056915:DNA Copy Number Variations; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D018628:Gene Dosage; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000201:enzymology / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D008875:Middle Aged; D008957:Models, Genetic; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D055291:Salivary alpha-Amylases / Q000235:genetics* / Q000378:metabolism; D012907:Smoking / Q000009:adverse effects; D055815:Young Adult
chemical_list: C524788:AMY1A protein, human; D055291:Salivary alpha-Amylases