Sex-specific, independent associations of insulin resistance with erythrocyte sedimentation rate in apparently healthy subjects.

Insulin resistance and erythrocyte sedimentation rate (ESR, a non-specific marker of inflammation) are known risk factors for cardiovascular disease. Although obesity is associated with increased ESR, it is unclear whether insulin resistance is associated with ESR in humans. The relationship between insulin resistance and ESR was studied in a cross-sectional, health-area based study of 140 (89 men and 51 women) apparently healthy Caucasians subjects. ESR, additional inflammatory markers [soluble tumor necrosis alpha receptors 1 and 2 (sTNFR1 and sTNFR2); C-reactive protein (CRP)], and insulin sensitivity (SI, frequently sampled intravenous glucose tolerance test with minimal model analysis) were assessed in all subjects. An interaction with sex was documented in the relationship between ESR and both insulin resistance and obesity (p < 0.05), as log ESR correlated with log SI in men (r=-0.29, p=0.009), but not in women (r=-0.14, p=0.33), and correlated with body mass index (BMI) in women (r=0.49, p=<0.0001), but not in men (r=0.15, p=0.16). On multivariate analyses, these associations proved to be independent of known covariates, such as age, hematocrit, smoking and additional inflammatory markers in both men and women. In a replication study, variables independently associated with ESR were also insulin resistance (homeostasis model assessment) in men and obesity markers (either BMI or fat mass) in women. In conclusion, ESR is independently associated with either insulin resistance or obesity in a sex-specific manner. These findings contribute to explain the known relationship of this inflammatory marker with cardiovascular disease.