Association between plasma irisin and glucose metabolism in pregnant women is modified by dietary n-3 polyunsaturated fatty acid intake.

Aims/introduction: The role of irisin in maternal glucose metabolism and how it would respond to dietary n-3 polyunsaturated fatty acid (n-3 PUFA) intake remains unclear. This study aimed to explore whether maternal plasma irisin is associated with glucose metabolism and whether this association is modified by dietary n-3 PUFA.

Materials And Methods: A total of 932 pregnant women (20-28 weeks' gestation) aged 20-45 years were recruited. Dietary n-3 PUFA was estimated using a validated quantitative food frequency questionnaire. Plasma irisin and insulin were tested by enzyme-linked immunosorbent assay, and insulin resistance (IR) was estimated using the homeostatic model assessment (HOMA). Gestational diabetes mellitus was diagnosed with a 75-g oral glucose tolerance test. Adjusted multivariable linear regression and logistic regression were carried out to examine the associations between plasma irisin and glucose metabolism. The moderating effect of dietary n-3 PUFA intake was determined by fully multiplicative models by including the interaction term.

Results: Maternal plasma irisin was negatively associated with HOMA-IR and oral glucose tolerance test 0 h glucose level (β -0.250, -0.067; corrected P-value for false discovery rate = 0.012, 0.018, respectively), positively associated with HOMA of insulin sensitivity (β 0.028; corrected P-value for false discovery rate = 0.012), but not associated with postprandial glucose or the risk of gestational diabetes mellitus. Furthermore, we found a moderating effect of dietary n-3 PUFA on the relationships of plasma irisin with HOMA-IR and HOMA of insulin sensitivity; these associations were strengthened with increased n-3 PUFA intake (β -0.037, 0.004; P = 0.014, 0.041, respectively).

Conclusions: Plasma irisin was negatively associated with HOMA-IR and fasting glucose, whereas it was positively associated with HOMA of insulin sensitivity in pregnant women. We first showed that these associations were modified by dietary n-3 PUFA intake.