Circulating GLP-1 Levels as a Potential Indicator of Metabolic Syndrome Risk in Adult Women

Abstract

Glucagon-like peptide-1 (GLP-1), an incretin hormone, plays an important role in regulating glucose homeostasis. In this study, the applicability of circulating GLP-1 levels as an early indicator of metabolic syndrome (MetS) risk was examined. Women without diagnosed diseases were grouped according to their number of MetS risk factors (MetS RFs) (no RFs as Super-healthy, n = 61; one or two RFs as MetS risk carriers, n = 60; 3 ≤ RFs as MetS, n = 19). The circulating GLP-1 levels and homeostasis model assessment insulin resistance (HOMA-IR) scores were significantly higher in the MetS group than in the other two groups. The GLP-1 levels correlated positively with adiposity, HOMA-IR, blood pressure, and high sensitivity C-reactive protein (hs-CRP), but not with fasting glucose and lipid profiles, whose significances were maintained after adjustments for age, smoking and drinking habits, menopausal status, and total calorie intake. The GLP-1 levels also increased proportionally with the number of MetS RFs. In the MetS group, the GLP-1 levels were much higher in individuals with obesity (body mass index ≥ 25 kg/m²). In conclusion, the circulating GLP-1 level may be applicable as a potential early indicator of MetS risk in women without diagnosed diseases. Further study with a large population is needed to confirm the conclusion.

Keywords: early indicator; glucagon-like peptide-1; metabolic syndrome; women.

Figure 1

Circulating glucagon-like peptide-1 (GLP-1) levels and homeostasis model assessment insulin resistance (HOMA-IR) scores in the study participants according to MetS status. Mean ± SD, tested after log transformation of the data; tested by the one-way analysis of variance with the Bonferroni method and with the general linear model after adjustment for confounding factors (age, total calorie intake, cigarette smoking, alcohol drinking, and/or menopausal status); P₀: Unadjusted p-value; P₁: P-value adjusted for confounding factors. Values sharing the same alphabet indicate no statistically significant differences among them. GLP-1: Glucagon-like peptide-1; HOMA-IR: Homeostatic model assessment of insulin resistance; MetS: Metabolic syndrome.

Figure 2

Circulating GLP-1 levels (a) and HOMA-IR scores (b) according to the number of MetS RFs. Mean ± SD, tested after log transformation of the data; tested by the one-way analysis of variance with the Bonferroni method and by the general linear model after adjustment for confounding factors (age, total calorie intake, cigarette smoking, alcohol drinking, and/or menopausal status); P₀: Unadjusted p-value, P₁: P-value adjusted for confounding factors. Values sharing the same alphabet indicate no statistically significant differences among them. GLP-1: Glucagon-like peptide-1; HOMA-IR: Homeostatic model assessment of insulin resistance; MetS RFs: Metabolic syndrome risk factors. Zero MetS RFs, n = 61; 1 MetS RF, n = 33; 2 MetS RFs, n = 27; 3 MetS RFs, n = 16; 4 MetS RFs, n = 3.

Figure 3

Circulating GLP-1 levels (a) and HOMA-IR scores (b) according to the combination of obesity and MetS status. Mean ± SD, tested after log transformation of the data; tested by the one-way analysis of variance with the Bonferroni method and with the general linear model with LSD after adjustment for confounding factors (age, total calorie intake, cigarette smoking, alcohol drinking, and menopausal status); P₀: Unadjusted p-value, P₁: P-value adjusted for confounding factors. Values sharing the same alphabet indicate no statistically significant differences among them. GLP-1: Glucagon-like peptide-1; HOMA-IR: Homeostatic model assessment of insulin resistance; MetS: Metabolic syndrome. Non-obesity group: Super-healthy, n = 57; MetS risk carriers, n = 31; and MetS, n = 2. Obesity group: Super-healthy, n = 4; MetS risk carriers, n = 29; and MetS, n = 17.