Evidence of sexual dimorphism in relationships between estrogen receptor polymorphisms and bone mass: the Hertfordshire study.

OBJECTIVE

To examine the relationship between estrogen receptor (ER) a and ss gene polymorphisms and bone mass.

METHODS

Bone mineral density (BMD) was measured at the lumbar spine and proximal femur twice, 4 years apart, in a cohort of 147 men and 125 women aged 61-73 years. Genomic DNA was extracted from whole blood samples, and genotyping for the ER (PvuII, XbaI, and AluI) was undertaken.

RESULTS

There were no significant associations between either the XbaI or PvuII polymorphisms and bone mass, or bone loss in the cohort as a whole. However, men homozygous for the aa beta receptor polymorphism had higher BMD at the lumbar spine (p = 0.05), femoral neck (p = 0.01), and total femur (p = 0.01). Women homozygous for aa had lower femoral neck and total femoral BMD than women of the AA or Aa genotypes (p = 0.01 and p = 0.02). Gender*ERbeta interaction terms were statistically significant (p = 0.02 for lumbar spine BMD, p = 0.0004 for femoral neck BMD, and p = 0.0003 for total femoral BMD, each test with 2 degrees of freedom unadjusted). Adjustment for sex hormone concentration and lifestyle factors made little difference to our results.

CONCLUSION

We found relationships between the ERbeta gene and the determination of bone mass among men and women in their seventh decade.