Apolipoprotein E phenotype associations with plasma lipoproteins and bone mass in postmenopausal women.

Objective: The aim of the study was to investigate the effects of apolipoprotein E (apo E) phenotype on plasma lipids and bone mass in postmenopausal Japanese women.

Methods: In 320 subjects aged 40-65 years (mean +/- SE, 54.0 +/- 0.6), apo E phenotype was determined by isometric electrophoresis. Phenotypic frequencies were 0.3% for E2/2 (n = 1), 8.1% for E3/2 (n = 26), 70.3% for E3/3 (n = 225), 0.6% for E4/2 (n = 2), 19.4% for E4/3 (n = 62) and 1.3% for E4/4 (n = 4). Apo E2/2 and apo E3/2 were classified as E2+ (n = 27); apo E3 homozygotes were placed in another group (E3/3; n = 225), as were apo E4/3 together with apo E4/4 subjects (group E4+; n = 66). Bone density and bone quality were assessed with a newly developed ultrasonic bone densitometer, and plasma lipids were also measured.

Results: Age, body mass index and years since menopause did not differ significantly between the three groups. The E4+ group had the highest levels of total cholesterol, low-density lipoprotein cholesterol and apolipoprotein B, significantly higher than in the E2+ group. Plasma lipoprotein(a) concentrations were significantly higher in the E4+ group than in the other two groups. Ultrasonic parameters of bone density and quality tended to be lower in the E4+ group than in the E2+ group.

Conclusions: The apo E4 allele was associated with high plasma cholesterol levels and an unfavorable change of bone structure in postmenopausal women.