Objective: The purpose of this study was to determine whether higher circulating interleukin-1 receptor antagonist (IL-1Ra), an anti-inflammatory cytokine, was associated with insulin resistance in postmenopausal women.
Methods: We measured IL-1Ra concentrations in 160 naturally postmenopausal women without a history of diabetes mellitus. A Pearson coefficient was computed to assess the relationship between plasma IL-1Ra and homeostasis model assessment of insulin resistance (HOMA-IR). The association between HOMA-IR and IL-1Ra plasma level above the median was assessed by logistic regression. Linear regression was used to explore the determinants of IL-1Ra plasma levels.
Results: A significant positive correlation existed between IL-1Ra and HOMA-IR (r = 0.42, p < .0001). The upper-tertile group of HOMA-IR was associated with approximately 4.5-fold increased risk of plasma IL-1Ra level above the median compared with the low-tertile group after adjustments. When multiple correlates were entered into the regression model simultaneously, only Log HOMA-IR remained significantly related to Log IL-1Ra (p = .007).
Conclusions: Our results demonstrated a positive association between plasma IL-1Ra and insulin resistance in postmenopausal women. This analysis suggested that insulin resistance was an important determinant of circulating IL-1Ra for these women.
Keywords: Association; insulin resistance; interleukin 1 receptor antagonist protein; postmenopause; women.