Apolipoprotein E polymorphism in a healthy Swedish population: Variation of allele frequency with age and relation to serum lipid concentrations

Abstract

We analyzed blood samples from 407 healthy Swedish individuals, 244 men and 163 women, ages 17 to 86 years, for apolipoprotein (apo) E isoforms and serum triglycerides, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and total cholesterol. Parallel genotyping by means of polymerase chain reaction (PCR)-amplified DNA was performed in 200 subjects. Identical results were obtained by genotyping and phenotyping in 95% of all subjects analyzed. The apo E allelic frequencies were 7.8% for ∈2, 71.9% for ∈3, and 20.3% for ∈4. Compared with other Caucasian populations, the present population had a high relative allelic frequency of e4. The ∈4 frequency decreased with increasing age and was significantly lower in individuals >60 years of age (14.7%). When controlling for age and sex, there were strong correlations between total serum and LDL cholesterol and the various ∈ alleles. The ∈4 and ∈3 alleles correlated positively with serum cholesterol and the ∈4 allele correlated positively with LDL cholesterol. In contrast, HDL cholesterol and serum triglycerides did not show any correlation to the allele types. Thus, the results demonstrate a considerable age variation of the ∈ allele frequency among healthy Swedes and an influence of apo E alleles on serum and LDL cholesterol concentrations.