LOS ANGELES (FRONTLINE MEDICAL NEWS) – The relationship between elevated C-reactive protein concentrations and increased all-cause mortality risk varies by gender and by race/ethnicity, an analysis of national data showed.

“Opportunities exist to discuss the importance of this marker and the relationship with mortality risk,” study author M. Ryan Richardson said in an interview following the World Congress on Insulin Resistance, Diabetes & Cardiovascular Disease. “Although we do not fully understand all of the mechanisms that underlie this harmful relationship, our results add to the limited evidence available to those working within the clinical setting.”

A 2017 meta-analysis of 14 prospective studies examining C-reactive protein (CRP) and mortality suggests that elevated CRP levels can independently predict all-cause and cardiovascular mortality risk ( Atherosclerosis. 2017 Apr;259:75-82 ), but there remains a paucity of evidence that examines the relationship between CRP and all-cause mortality risk according to gender and race/ethnicity. For the current analysis, Mr. Richardson, an instructor in the department of clinical and applied movement science at the University of North Florida, Jacksonville, and his associates drew from the 1999-2006 National Health and Nutrition Examination Survey, a nationally representative sample of U.S. adults stratified by gender and race/ethnicity. Elevated CRP was defined as greater than 3 mg/L to 10 mg/L, and the dependent variable of interest was all-cause mortality. The National Center for Health Statistics linked death records from the National Death Index to the NHANES participants’ sequence numbers.

A total of 4,383 adults between the ages of 30 and 79 years were included in the analysis. After the researchers adjusted for age, race, education, smoking, alcohol consumption, cardiovascular disease, waist circumference, and aerobic physical activity, they observed a significantly higher risk for all-cause mortality in non-Hispanic black males (hazard ratio, 2.04) and Mexican-American females (HR, 2.24). “We were surprised that this relationship was also independent of measured waist circumference and any volume of reported aerobic physical activity, which are both acknowledged as strong mediator variables in this relationship,” Mr. Richardson said. The HR in non-Hispanic white males approached but did not reach statistical significance (HR, 1.32).

He acknowledged certain limitations of the study, including its cross-sectional design. “We cannot make causal inferences based on this data,” he said.

The researchers reported having no financial disclosures.

SOURCE: M. Ryan Richardson et al.