Low serum amylase in association with metabolic syndrome and diabetes: A community-based study

Abstract

Background: Low serum amylase levels may reflect impaired exocrine-endocrine relationship in the pancreas. However, few clinical studies have addressed this issue. Therefore, in this epidemiological study, we investigated whether low serum amylase was associated with the pathogenesis of impaired insulin action: metabolic syndrome (MetS) and diabetes.

Research design and methods: Serum amylase, cardiometabolic risk factors, MetS (Adult Treatment Panel III criteria), and diabetes were examined in 2,425 asymptomatic subjects aged 30-80 years who underwent medical checkups recently (April 2009-March 2010) and 5 years ago.

Results: Clinical variables, except for age and estimated glomerular filtration rate (eGFR), shifted favorably with increasing serum amylase levels. Plasma glucose levels at 1- and 2-hr during OGTT increased significantly with decreasing serum amylase levels. Multiple logistic analyses showed that, compared with highest quartile of serum amylase, lowest quartile was associated with increased risk for MetS and diabetes after adjustment for confounding factors [odds ratio (95% CI), 2.07 (1.39-3.07) and 2.76 (1.49-5.11), respectively]. In subjects who underwent checkups 5 years ago (n = 571), lower amylase at the previous checkup were associated with larger numbers of metabolic abnormalities at the recent checkup. The fluctuation over time in serum amylase levels in subjects with low serum amylase at the previous checkup was slight and was unaffected by kidney dysfunction.

Conclusions: Our results indicate that low serum amylase is associated with increased risk of metabolic abnormalities, MetS and diabetes. These results suggest a pancreatic exocrine-endocrine relationship in certain clinical conditions.

Figure 1

Serum amylase levels according to the number of ATP-III-MetS components (NAMC). The numbers of nonsmokers with NAMCs of 0, 1, 2 and 3-5 are 472, 580, 438 and 306, respectively. The numbers of smokers with NAMCs of 0, 1, 2 and 3-5 are 169, 184, 144 and 132, respectively. The serum amylase level decreased significantly with increasing NAMC in both nonsmokers and smokers (both P < 0.0001, ANOVA), and was significantly different between nonsmokers and smokers (P < 0.0001, ANOVA). White triangles = nonsmokers, black triangles = smokers. Values are means ± SE.

Figure 2

Plasma glucose levels during OGTTs. The numbers of subjects in Q1, Q2, Q3 and Q4 are 290, 312, 322 and 320, respectively. The cutoff values for each quartile are presented in Table 1. Plasma glucose levels increased significantly with decreasing serum amylase levels (P = 0.002, ANOVA). Values are means ± SE.

Figure 3

Changes over 5 years for NAMC-BMI and its components. A: NAMC-BMI, B: Proportion of elevated blood pressure, C: Proportion of high FPG, D: Proportion of dyslipidemia. The numbers of subjects in Q1, Q2, Q3 and Q4 are 144, 149, 157, and 121, respectively. NAMC-BMI and proportions of elevated blood pressure decreased significantly with increasing amylase quartile recorded 5 years ago (P = 0.02 and P = 0.006, ANOVA, respectively). No significant association was observed between prior quartiles of serum amylase and dyslipidemia and high FPG. NAMC: number of ATP-III-MetS components.

Figure 4

Changes in serum amylase over 5 years. The numbers of subjects in Q1, Q2, Q3 and Q4 [further divided according to current kidney functions as eGFR (ml/min/1.73 m²)] are 144 (25, 105, 14), 149 (16, 120, 13), 157 (17, 116, 24), and 121 (9, 86, 26), respectively. Current serum amylase increased significantly with decreasing amylase quartile recorded 5 years ago and decreasing current eGFR (P = 0.004 and P = 0.02, ANOVA, respectively). Values are means ± SE.