Association between smoking and serum GlycA and high-sensitivity C-reactive protein levels: The Multi-Ethnic Study of Atherosclerosis (MESA) and Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Background--Inflammation is suggested to be a central feature of atherosclerosis, particularly among smokers. We studied whether inflammatory biomarkers GlycA and high-sensitivity C-reactive protein are associated with cigarette smoking. Methods and Results--A total of 11 509 participants, 6774 from the MESA (Multi-Ethnic Study of Atherosclerosis) and 4735 from ELSA-Brasil (The Brazilian Longitudinal Study of Adult Health) were included. We evaluated the cross-sectional association between multiple measures of smoking behavior and the inflammatory biomarkers, GlycA and high-sensitivity C-reactive protein, using regression models adjusted for demographic, anthropometric, and clinical characteristics. Participants were 57.7±11.1 years old and 46.4% were men. Never, former, and current smokers comprised 51.7%, 34.0%, and 14.3% of the population, respectively. Multivariable-adjusted mean absolute difference in GlycA levels (μmol/L) with 95% confidence interval (CI) were higher for former (4.1, 95% CI, 1.7-6.6 μmol/L) and current smokers (19.9, 95% CI, 16.6-23.2 μmol/L), compared with never smokers. Each 5-unit increase in pack-years of smoking was associated with higher GlycA levels among former (0.7, 95% CI, 0.3-1.1 μmol/L) and current smokers (1.6, 95% CI, 0.8-2.4 μmol/L). Among former smokers, each 5-year increase in time since quitting smoking was associated with lower GlycA levels (-1.6, 95% CI, -2.4 to -0.8 μmol/L) and each 10-unit increase in number of cigarettes/day was associated with higher GlycA among current smokers (2.8, 95% CI, 0.5-5.2 μmol/L). There were similar significant associations between all measures of smoking behavior, and both log-transformed GlycA and high-sensitivity C-reactive protein. Conclusions--Acute and chronic exposure to tobacco smoking is associated with inflammation, as quantified by both GlycA and high-sensitivity C-reactive protein. These biomarkers may have utility for the study and regulation of novel and traditional tobacco products.