Bidirectional Temporal Relationship Between Obesity and Hyperinsulinemia: Longitudinal Observation From a Chinese Cohort

Abstract Background: This study aims to investigate the temporal sequences between obesity and hyperinsulinemia (insulin, HOMA-IR, or HOMA-%β) and examine the impacts of different obesity measures (body mass index, BMI; waist circumference, WC; hip waist circumference, HC; waist-to-hip ratio, WHR) on the temporal patterns between obesity and hyperinsulinemia in Chinese adults. Methods: The longitudinal cohort consisted of 2493 participants (860 males and 1633 female, mean age 56.71 years at follow-up) for whom measurements of obesity and hyperinsulinemia measures were collected twice between 2010 and 2014, with an average follow-up time of 3 years. Cross-lagged panel analysis was used to examine the temporal relationship between obesity and hyperinsulinemia. Results: After the adjustment of age, sex, smoking, drinking and follow-up years, in the BMI-insulin model, the path coefficient (β2=0.229; P<0.001) of baseline BMI to follow-up insulin was significantly greater than the path coefficient (β1=0.073; P<0.001) of baseline insulin to follow-up BMI (P<0.001 for β2>β1). In the WHR-insulin model, the path coefficient (β1=0.152; P<0.001) of baseline insulin to follow-up WHR was significantly greater than the path coefficient (β2=0.077; P<0.001) of baseline WHR to follow-up insulin (P=0.007 for β1>β2). In the WC/HC-insulin model the path coefficients of baseline insulin to follow-up WC or HC (β1s) were also greater than the path coefficients of baseline WC or HC to follow-up insulin (β2s), but the difference between β1s and β2s were not significant. The similar temporal patterns were founded between obesity measures with HOMA-IR or HOMA-%β. Conclusions: These findings indicate that there is a bidirectional relationship between obesity and hyperinsulinemia, and abdominal obesity measures are more sensitive to hyperinsulinemia measures than BMI.