Resistin levels decrease as insulin resistance increases in a Mexican-American cohort.

Abstract

Links between resistin, insulin resistance (IR), and resistin-stimulated cytokine signaling remain unknown in Mexican-Americans. A Mexican-American cohort was examined to determine (1) relationships between circulating resistin and IR, (2) resistin's associations with cytokines and demographic and anthropometric variables, and (3) similar measurements with other adipokines. For cross sectional analyses, 953 adults (367 males and 586 females) in the Cameron County Hispanic Cohort (CCHC) were stratified into three groups: normal glucose tolerance, prediabetes, and diabetes mellitus. Differences in resistin and other adipokine levels were examined using linear regression via unadjusted model (Model 1), model adjusted for cytokines (Model 2), and model further adjusted for demographic and anthropometric variables (Model 3). HOMA-IR increased with worsening glucose tolerance (p<0.0001). In all models, resistin significantly decreased as glucose tolerance deteriorated. Model 3 resistin was positively associated with IL-1β (p=0.0252) and IL-8 (p<0.0001), inversely associated with TNF-α (p=0.0352), but nonsignificantly associated with IL-6 (p=0.8671). Model 3 leptin was significantly lower in diabetes mellitus compared to other groups (p<0.005) and positively associated with female sex (p<0.0001), age (p=0.024), and BMI (p<0.0001), without significant cytokine associations. Adiponectin displayed no significant associations with glucose tolerance, but was significantly associated with sex, BMI, and lipids (Model 3). Resistin unexpectedly decreased as IR increased while supporting evidence of a resistin-stimulated cytokine pathway in this Mexican-American cohort. Leptin fell with elevated IR after adjusting for cytokines, demographic and anthropometric variables. Adiponectin nonsignificantly decreased as IR increased while showing significant associations with sex, BMI, and lipids.