Hyperlipoproteinaemia, ApoE Genotype and Bone Mineral Density

Overview

Background.
Both atherosclerosis and osteoporosis often appear together, especially in the elderly; usually theyare regarded as independent entities. Only recently epidemiological evidence occurred suggesting possible associ -ations between these diseases. Several groups of factors (genetic, hormonal and biochemical) have been studied toaccount for this association. Among the genetic factors, apolipoprotein E has been studied most extensively; someresults indicate that carriers of E4 allele are at increased risk of osteoporosis. A possible influence of plasmalipoproteins and of tissue ischaemia on bone metabolism has also been studied.Aim of the study. To test the hypothesis that there is an association between apolipoprotein E, plasma lipidconcentrations and bone mineral density.Methods. We examined 18 apolipoprotein E2/2 and E4/4 homozygotes and 130 postmenopausal women. Bonemineral density and plasma triglycerides, total and HDL cholesterol were determined in both groups; in apolipoproteinE homozygotes biochemical markers of bone turnover were also measured.Results. No significant differences in bone mineral density and bone remodelling were found between the E2/2and E4/4 homozygotes. A negative correlation between lumbar spine bone mineral density and cholesterol andtriglyceride concentrations (r=0.20-0.39) was observed both in postmenopausal women and apolipoprotein Ehomozygotes.Conclusion. We didn’t observe any association of apolipoprotein E genotype with bone mineral density andbiochemical markers of bone metabolism. A negative association between plasma lipid concentrations and bonemineral density supports the hypothesis of harmful effect of hyperlipidaemia on bone metabolism.

Key words:
bone mineral density, cholesterol, triglycerides, apolipoprotein E.