Relationship between circulating irisin levels and overweight/obesity: A meta-analysis

Abstract

Background: Currently, the findings about irisin as a novel myokine related to obesity are inconsistent in overweight/obese people. To our knowledge, no systematic analysis has been conducted to evaluate the relationship between irisin levels and overweight/obesity.

Aim: To evaluate the association between circulating irisin levels and overweight/obesity.

Methods: The Cochrane Library, MEDLINE, SCOPUS, and the ISI Web of Science were searched to retrieve all of the studies associated with circulating irisin levels and overweight/obesity. Standard mean difference values and 95% confidence intervals (CI) were estimated and pooled using meta-analysis methodology.

Results: A total of 18 studies were included in our meta-analysis containing 1005 cases and 1242 controls. Our analysis showed that the circulating irisin level in overweight/obese people was higher than that in overall healthy controls (random effects MD = 0.63; 95%CI: 0.22-1.05; P = 0.003). In the subgroup analysis by ethnicity, the irisin level was higher in overweight/obesity people than that in controls in Africa (random effects MD = 3.41; 95%CI: 1.23-5.59; P < 0.05) but not in European, Asian, or American populations. In addition, in a subgroup analysis by age, the results showed that obese children exhibited a higher irisin level than controls (random effects MD = 0.86; 95%CI: 0.28-1.43; P < 0.05).

Conclusion: This meta-analysis provides evidence that circulating irisin is higher in obese individuals compared to healthy controls and it is important to identify the relationship between circulating irisin levels and overweight/obesity in predicting overweight/obesity.

Keywords: Body mass index; Irisin; Myokines; Overweight/obesity.

Figure 1

Flow chart of article selection for meta-analysis.

Figure 2

Forest plot of meta-analysis of the association between irisin and obesity.

Figure 3

Forest plot of irisin in obese patients in different racial groups. A: Forest plot of irisin in obese patients in Asia; B: Forest plot of irisin in obese patients in Europe; C: Forest plot of irisin in obese patients in Africa; D: Forest plot of irisin in obese patients in America.

Figure 4

Forest plot of irisin in obese patients in children and adults. A: Forest plot of irisin in obese children vs nonobese children; B: Forest plot of irisin in obese adults vs nonobese adults.

Figure 5

Analysis of publication bias. A: Begg’s funnel plot had the expected funnel shape (Begg’s test P = 0.544); B: Egger’s publication bias plot (Egger’s test P = 0.65).