Objectives. Elevated C-reactive protein (CRP) is a suggested risk marker for cardiovascular disease. We aimed at investigating the distribution and determinants of CRP levels in young adults.
Design. Population-based study.
Subjects. A total of 2120 participants aged 24–39 years.
Main outcome measures. Distribution of CRP, and the relationship between CRP and risk factors.
Results. CRP concentration (mean ± SD) was 1.43 ± 3.26 mg L−1 in men, 1.36 ± 2.36 mg L−1 in women who did not use oral contraceptives (OC) and 3.69 ± 6.01 mg L−1 in women who used OCs. In total, 8.8% of men, 10.3% of non-OC user women and 35.3% of OC user women had CRP concentration >3 mg L−1 (recommended cut-off point of high risk for cardiovascular disease). In univariate analysis, CRP was associated with obesity indices and physical activity amongst both sexes. In men, the multivariate correlates of CRP included waist circumference (P < 0.0001), smoking (<0.0001) and HDL cholesterol (P = 0.024) (inverse association). These three variables explained 21.9% (model R2) of the total variation in CRP, waist circumference having the greatest influence (partial R2 = 19.6%). In women, the multivariate correlates of CRP included OC use (P < 0.0001), body mass index (BMI) (P < 0.0001), triglycerides (<0.0001) and physical activity (P = 0.025) (inverse association). These four variables explained 38.2% (model R2) of the total variation in CRP, with OC use (partial R2 = 18.4%) and BMI (partial R2 = 18.0%) having the greatest influence.
Conclusions. The determinants of CRP level include obesity and smoking in men, and obesity, OC use and physical activity in women. About one in three of healthy women who use OCs have CRP concentration exceeding 3 mg L−1.