Association of plasma lipid levels with apolipoprotein E polymorphism in Type 2 diabetes

To evaluate the distribution of apolipoprotein E polymorphism in patients with Type 2 diabetes and their impact on plasma lipid levels.

Unrelated Type 2 diabetic patients (n = 298) treated by diet and sulfonylurea and not receiving lipid-lowering regimens, elderly (n = 98) and young (n = 101)unrelated healthy control subjects in Hungary.

Apolipoprotein E genotypes were identified by PCR amplification and subsequent restriction endonuclease digestion.

The distribution of the most frequent genotypes in the diabetes group was E2/3 8.7%, E3/3 78.2%, E3/4 12.8%, in the elderly group E2/3 9.2%, E3/3 78.6%, E3/4 12.2% and in the young group E2/3 11.9%, E3/3 62.4%, E3/4 24.8%. The frequencies of allele e4 in the diabetes and in the elderly control group were significantly lower than in the young control group (both P < 0.05). Associations were found between the e4 allele and increased triglyceride level in the diabetes group, the e2 allele and decreased total cholesterol and LDL-cholesterol levels both in the elderly and young control groups (both P < 0.01).

The lower frequency of allele e4 in both the elderly and diabetes groups, may be explained by an increased morbidity and mortality in middle-aged carriers of apo e4 allele. The increased risk of e4 carriers in Type 2 diabetes may be partly mediated by a higher triglyceride level.