Bidirectional temporal relationships between uric acid and insulin and their joint impact on incident diabetes.

Background And Aims: This study aims to examine the temporal relationship between uric acid (UA) and insulin and their joint impact on T2DM in middle-aged adults.

Methods And Results: The cohort consisted of 1351 non-diabetic adults who had serum UA and insulin measured twice at baseline and follow-up over 7.7 years on average, and incidence of T2DM in the outcome survey12.2 years later. After adjusting for covariates, the path coefficient from baseline UA to follow-up insulin was 0.082 (p < 0.001); the path from baseline insulin to follow-up UA was 0.060 (p = 0.030). In the mediation model with baseline UA as the predictor, total effect of baseline UA on incident T2DM was 0.089 (p = 0.016). The mediation effect through follow-up insulin on the UA-T2DM association was 28.1%. The direct effect of baseline UA on T2DM (0.064) became nonsignificant (p = 0.078). In the mediation model with baseline insulin as the predictor, total effect of baseline insulin on T2DM was 0.218 (p < 0.001). The mediation effect through follow-up UA on the insulin-T2DM association was 5.5%. The direct effect of baseline insulin on T2DM (0.206) remained significant (p < 0.001). The baseline hyperinsulinemia-follow-up hyperuricemia group showed the highest incidence rate of T2DM (27.9%).

Conclusions: The bidirectional temporal relationship suggests that UA and insulin influence each other in non-diabetic individuals, and the directionality plays pathogenic roles in the development of T2DM.