Association of C-reactive protein with surrogate measures of insulin resistance among nondiabetic US from National Health and Nutrition Examination Survey 1999-2002.

BACKGROUND: Increased C-reactive protein (CRP) concentration and insulin resistance (IR) are associated with increased rates of adverse cardiovascular events. We sought to examine the relationship of CRP with surrogate measures of IR among nondiabetic adults in the US.
METHODS: We conducted analyses using data from the National Health and Nutrition Examination Survey 1999-2002. We analyzed a nationally representative sample of 2514 men and nonpregnant women age > or = 20 years who were non-Hispanic white, non-Hispanic black, or Mexican American.
RESULTS: After adjustment for age, sex, race/ethnicity, smoking status, systolic blood pressure, and serum concentrations of HDL cholesterol, LDL cholesterol, and triglyceride, CRP was significantly associated with 10 IR measures (all P values <0.01). The strength of the association attenuated after further adjustment for waist circumference (change in adjusted regression coefficients ranging from 60.0% to 75.1%). The association of CRP with each IR surrogate was similar (standardized regression coefficient ranges from 0.06 to 0.09). The association of CRP (>3 vs <1 mg/L) with the homeostasis model for assessment of IR (> or = 75th vs <75th percentile) was statistically significant among people with a body mass index > or = 30 kg/m(2) (odds ratio, 2.6; 95% CI, 1.3-5.1) or with a body mass index <25 kg/m(2) (odds ratio, 2.5; 95% CI, 1.5-4.2).
CONCLUSIONS: CRP was significantly associated with the surrogate measures of IR among nondiabetic adults. Obesity may play an important role in the association of CRP with IR in this nationally representative sample.