Comparison of the stability of glycoprotein acetyls and high sensitivity C-reactive protein as markers of chronic inflammation.

It has been suggested that glycoprotein acetyls (GlycA) better reflects chronic inflammation than high sensitivity C-reactive protein (hsCRP), but paediatric/life-course data are sparse. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) and UK Biobank, we compared short- (over weeks) and long-term (over years) correlations of GlycA and hsCRP, cross-sectional correlations between GlycA and hsCRP, and associations of pro-inflammatory risk factors with GlycA and hsCRP across the life-course. GlycA showed high short-term (weeks) stability at 15 years (r = 0.75; 95% CI = 0.56, 0.94), 18 years (r = 0.74; 0.64, 0.85), 24 years (r = 0.74; 0.51, 0.98) and 48 years (r = 0.82 0.76, 0.86) and this was comparable to the short-term stability of hsCRP at 24 years. GlycA stability was moderate over the long-term, for example between 15 and 18 years r = 0.52; 0.47, 0.56 and between 15 and 24 years r = 0.37; 0.31, 0.44. These were larger than equivalent correlations of hsCRP. GlycA and concurrently measured hsCRP were moderately correlated at all ages, for example at 15 years (r = 0.44; 0.40, 0.48) and at 18 years (r = 0.55; 0.51, 0.59). We found similar associations of known proinflammatory factors and inflammatory diseases with GlycA and hsCRP. For example, BMI was positively associated with GlycA (mean difference in GlycA per standard deviation change in BMI = 0.08; 95% CI = 0.07, 0.10) and hsCRP (0.10; 0.08, 0.11). This study showed that GlycA has greater long-term stability than hsCRP, however associations of proinflammatory factors with GlycA and hsCRP were broadly similar.