Plasma viscosity, immunoglobulins and risk of cardiovascular disease and mortality: new data and meta-analyses.

Aims: Associations of plasma viscosity and plasma Ig levels (a determinant of viscosity) with incident coronary heart disease (CHD) events; and with CHD, cardiovascular disease (CVD: CHD and stroke) and all-cause mortalities.

Methods: Meta-analysis of plasma viscosity levels from the MONitoring of trends and determinants of CArdiovascular (MONICA)/Cooperative Health Research in the Region of Augsburg, MONICA Glasgow and Speedwell Studies; and five other published studies. Meta-analysis of IgA, IgG and IgM levels from the Augsburg, Glasgow and Speedwell studies; and one other published study.

Results: Over median follow-up periods of 14-26 years, there were 2270 CHD events, and 4220 all cause deaths in 28 605 participants with baseline plasma viscosity measurements. After adjustment for major risk factors, (HRs; 95% CIs) for a 1 SD increase in viscosity were 1.14 (1.09 to 1.20) for CHD events; and 1.21 (1.17 to 1.25) for all-cause mortality. 821 CHD events and 2085 all-cause deaths occurred in 8218 participants with baseline Ig levels. For CHD events, adjusted HRs for 1 SD increases in IgA, IgG and IgM were, respectively, 0.97 (0.89 to 1.05); 0.95(0.76 to 1.17) and 0.90 (0.79 to 1.03). Corresponding adjusted HRs for all-cause mortality were 1.08 (95% CI 1.02 to 1.13), 1.03 (95% CI 0.94 to 1.14) and 1.01 (95% CI 0.96 to 1.06).

Conclusions: After risk factor adjustment, plasma viscosity was significantly associated with risks of CHD events; and with CHD, CVD and all-cause mortalities. We found no significant association of IgA, IgG or IgM levels with incident CHD events or mortality, except for a borderline association of IgA with all-cause mortality.