Apolipoprotein E polymorphism is not associated with spinal bone mineral density in peri- and postmenopausal Greek women

Abstract

Objectives: A number of studies have shown a positive relation between ApoE gene and osteoporosis or fracture risk but this finding has not been uniform in all populations studied. The aim of the present study was to determine the possible effect of ApoE gene polymorphism on spinal bone mineral density and metabolic bone markers in Greek women.

Methods: One hundred and forty-seven healthy peri- and postmenopausal women (mean age 54.3 +/- 7.8 years) participated in the study. In all participants, ApoE gene genotype was determined and spinal bone mineral density (BMD) as well as biochemical bone markers were measured. The ApoE genotypes distribution was 0.7% (n = 1) for E2/2, 5.4% (n = 8) for E2/3, 2% (n = 3) for E2/4, 73.5% (n = 108) for E3/3, 16.3% (n = 24) for E3/4 and 2% (n = 3) for E4/4. Participants were divided in two groups according to the presence of the E4 haplotype: E4 carriers (n = 30) and E4 non-carriers (n = 117).

Results: Spinal BMD was similar in the two groups, after adjusting for age, weight, height and years since menopause (mean +/- S.D., 0.835 +/- 0.16 g/cm2 in E4 non-carriers versus 0.831 +/- 0.16 g/cm2 in E4 carriers, P = 0.99). Serum osteocalcin levels did not differ significantly in the two groups (median (interquartile range, IQR), 0.55 (0.58) nmol/l in E4 non-carriers versus 0.51 (0.43) nmol/l in E4 carriers), whereas urinary hydroxyproline/creatinine ratio was significantly higher in the E4 non-carriers group (median (IQR), 5.18 (6.04) micromol/mmol in E4 non-carriers versus 1.73 (3.45) micromol/mmol in E4 carriers, P < 0.01). Urinary pyridinoline/creatinine and deoxypyridinoline/creatinine ratios, measured in a subgroup of 51 women, were similar between ApoE carriers and non-carriers, respectively (median (IQR), 25.1 (9.3) nmol/mmol in E4 non-carriers versus 21.8 (7) nmol/mmol in E4 carriers and 6.7 (3.1) nmol/mmol in E4 non-carriers versus 7 (2.2) nmol/mmol in E4 carriers).

Conclusion: In conclusion, in a Greek female postmenopausal population, ApoE gene does not seem to play an important role in determining BMD and neither does it affect the majority of metabolic bone markers.