High levels of blood viscosity, hematocrit linked to risk for type 2 diabetes

Elevated blood viscosity and hematocrit should be carefully monitored as emerging risk factors for insulin resistance and type 2 diabetes, according to recently published data.

To determine the role of elevated blood viscosity in insulin resistance and type 2 diabetes, researchers reviewed data from the Atherosclerosis Risk in Communities (ARIC) study. The prospective epidemiologic study was conducted in four U.S. communities from 1987 to 1998.

The researchers examined longitudinal data from 12,881 adults without diabetes aged 45 to 64 years. Using a validated formula based on hematocrit and total plasma proteins, the researchers estimated whole blood viscosity at baseline. At baseline, the researchers reported an independent association between estimated blood viscosity and features of metabolic syndrome.

Whole blood viscosity and hematocrit predicted incident type 2 diabetes in a graded fashion when analyzed in models adjusted for known predictors of diabetes. According to the researchers, adults in the highest quartiles of blood viscosity (HR=1.68; 95% CI, 1.53-1.84) and hematocrit (HR=1.63; 95% CI, 1.49-1.79) were more than 60% more likely to develop diabetes than adults in the lowest quartiles.

Based on their findings, the researchers concluded that, “elevated blood viscosity and hematocrit deserve attention as emerging risk factors for insulin resistance and type 2 diabetes mellitus.” – by Stacey L. Adams

Am J Epidemiol. 2008;168:1153-1160.

This may be an example of confounding variables and in no way suggests that viscosity may be a causal factor in diabetes. Blood viscosity is highly associated with increased hematocrit which, in turn, may relate to sleep apnea, a characteristic of abdominal obesity — a known diabetic provocateur.

– Harry S. Jacob, MD

HemOnc Today Chief Medical Editor