Low serum levels of high-molecular weight adiponectin in Indo-Asian women during pregnancy: evidence of ethnic variation in adiponectin isoform distribution.

Indo-Asian ethnicity is associated with an increased risk of type 2 diabetes and cardiovascular disease (CVD) that is not reconciled by conventional risk factors (1,2). In a recent study (3), we found that pregnant Indo-Asian women exhibited strikingly low serum levels of adiponectin, a protein with putative insulinsensitizing and antiatherogenic activity. Hypoadiponectinemia has since been demonstrated in both Indo-Asian male and nonpregnant female subjects (4–6). Thus, hypoadiponectinemia may be a generalized phenomenon in people of Indo-Asian descent that could contribute to their increased risk of type 2 diabetes and CVD. It has recently emerged that adiponectin circulates in oligomeric complexes, with its high–molecular weight (HMW) isoform mediating insulinsensitizing and vasculature-protective effects (7,8). Accordingly, Scherer and colleagues (7) have proposed the ratio of the HMW isoform to total adiponectin (SA) (expressed as a percentage) as a measure of the biological activity of adiponectin. Given the risk of type 2 diabetes and CVD in Indo-Asians, we hypothesized that hypoadiponectinemia in this ethnic group may reflect selective deficiency of the HMW isoform (i.e., low SA). Therefore, to test this hypothesis, we sought to assess the relationship between SA and ethnicity within our earlier study of pregnant women.