Body mass index, diabetes, and C-reactive protein among U.S. adults.

OBJECTIVE: The author examined the relationship between C-reactive protein and BMI and diabetes status among 16,573 participants aged > or = 20 years of the Third National Health and Nutrition Examination Survey (1988-1994). RESEARCH DESIGN AND METHODS: The study had a cross-sectional design. RESULTS: Geometric mean concentrations of C-reactive protein were lowest among individuals with a BMI or = 85th percentile of the sex-specific C-reactive protein concentration distribution) among participants with a BMI of 25 to or = 40 kg/m2 were 1.51 (95% CI 1.23-1.86), 3.19 (2.60-3.91), 6.11 (4.67-7.98), and 9.30 (6.43-13.46), respectively, compared with participants with a BMI < 25 kg/m2. C-reactive protein concentrations were lowest among those individuals without diabetes or with impaired fasting glucose and highest among those with newly or previously diagnosed diabetes. Compared with participants with a normal fasting glucose, participants with impaired fasting glucose, newly diagnosed diabetes, and previously diagnosed diabetes had 0.99 (0.72-1.37), 1.84 (1.25-2.71), and 1.59 (1.25-2.01) odds of having an elevated C-reactive protein concentration after adjustment for age, sex, race or ethnicity, education, and BMI. CONCLUSIONS: These results confirm cross-sectional findings from previous studies that show elevated C-reactive protein concentrations among individuals who are obese or have diabetes. The implications of these findings, however, remain unclear.