Five-year intra-individual variability in C-reactive protein levels in a Japanese population-based study - The Jichi Medical School Cohort Study at Yamato, 1993-1998

C-reactive protein (CRP) is an acute-phase reactant that is related to futu re cardiovascular events. However, little is known about the long-term intr a-individual stability of CRP in community residents. The 5-year intra-indi vidual correlation of CRP levels was examined in the Jichi Medical School C ohort Study in Japan. CRP measurements were obtained in 1993 and in 1998 fr om 388 presumptively healthy individuals aged 30-69 years at baseline. The Pearson's correlation coefficient of CRP between baseline and follow-up mea surements was 0.43 (95% confidence interval (CI): 0.34-0.51). Additional an alyses by sex and smoking status at baseline revealed similar coefficients. The correlation coefficient of CRP was lower than that of other classical risk factors, such as body-mass index (BMI), blood pressure, and total and high-density lipoprotein (HDL) cholesterol. A subgroup of individuals with higher levels of CRP at both baseline and follow-up measurements had higher BMI, hemoglobin Ale, and plasma fibrinogen, and lower levels of HDL-choles terol than others, even after adjusting for age, sex, and smoking status in a multiple logistic model. In conclusion, the stability of CRP levels was statistically significant in a long-term population-based study. A subgroup with higher levels of CRP who had an aggregation of cardiovascular risk fa ctors was identified by the 2 measurements.