Inflammation biomarkers and incident coronary heart disease: the Reasons for Geographic And Racial Differences in Stroke Study

Abstract

Background: Individual inflammation biomarkers are associated with incident coronary heart disease (CHD) events. However, there is limited research on whether the risk for incident CHD is progressively higher with a higher number of inflammation biomarkers in abnormal levels.

Methods: We used data from 15,758 Reasons for Geographic and Racial Differences in Stroke (REGARDS) study participants aged ≥45 years without a history of CHD at baseline in 2003-2007. Abnormal levels of baseline high-sensitivity C-reactive protein, leukocyte count and serum albumin were defined as ≥3.8 mg/L (3rd tertile), ≥6.3 x 10⁹ cells/L (3rd tertile), and <4.0 g/dL (1st tertile), respectively. The outcome was a composite of incident myocardial infarction or CHD death.

Results: Overall, 38.9% (n = 6,123) had 0, 36.6% (n = 5,774) had 1, 19.8% (n = 3,113) had 2 and 4.7% (n = 748) had 3 biomarkers of inflammation in abnormal levels. Over a median follow-up of 11.4 years, 954 (6.1%) participants had incident CHD. The rate of incident CHD per 1000 person-years for individuals with 0, 1, 2, and 3 biomarkers of inflammation in abnormal levels was 4.4 (95% confidence interval [CI]: 3.9-5.0), 6.3 (95% CI: 5.6-6.9), 8.8 (95% CI: 7.8-9.9), and 10.6 (95% CI: 8.1-13.1), respectively. Multi-variable adjusted hazard ratios for incident CHD associated with 1, 2 and 3 versus no inflammation biomarker in abnormal levels were 1.26 (95% CI: 1.07-1.49), 1.72 (95% CI: 1.43-2.07), and 1.84 (95% CI: 1.37-2.47), respectively (P-trend < .001).

Conclusions: The number of inflammation markers in abnormal levels was associated with increased risk of incident CHD after multi-variable adjustment.

Keywords: Coronary heart disease; Inflammation biomarkers; Leukocyte count; Myocardial infarction; Serum albumin; hsCRP.