Background:
Ghrelin, a
peptide mainly produced by stomach X-A cells. It plays a pivotal role in the regulation of food intake and energy metabolism, including
glucose metabolism and
insulin sensitivity. However, the correlation between circulating
ghrelin levels and
insulin resistance in
obesity remained uncertain. This meta-analysis aimed to clarify the association between
ghrelin and IR in
obesity. Methods: A systematic literature search was performed using PubMed, EMBASE, Cochrane Library and Web of Science until April 18, 2018 with the keywords "
ghrelin" and "
insulin resistance." Two independent reviewers selected studies and assessed data. Subgroup analyses were performed to search for sources of heterogeneity. Funnel plots and Egger's test were used to detect publication bias. A random-effects model was used to calculate the pooled effect size. Results: Ten studies with 546 participants were included in this meta-analysis. We found that
ghrelin levels were negatively correlated with IR in obese individuals. (r = -0.31; 95% CI: -0.45 to -0.18). Subgroup analysis revealed that circulating
ghrelin levels were significantly negatively correlated with IR in people with normal fasting
blood glucose (FBG) (<6.9 mmol/dl) (r = -0.28; 95% CI: -0.47 to -0.09, I 2 = 39.5%), while there was no relationship between circulating
ghrelin levels and IR in the high FBG group (>6.9 mmol/dl) (r = -0.15; 95% CI: -0.33 to 0.03, I 2 = 0.0%). Publication bias was insignificant (Egger's test: P = 0.425). Conclusion: In
obesity, circulating
ghrelin levels were significantly negative correlated with
insulin resistance in individuals with normal fasting
blood glucose.