Relation of common allelic variation at vitamin D receptor locus to bone mineral density and postmenopausal bone loss: cross sectional and longitudinal population study.

OBJECTIVE: To determine whether common allelic variation at the vitamin D receptor locus is related to bone mineral density and postmenopausal bone loss. DESIGN: Cross sectional and longitudinal population study. SETTING: Outpatient clinic in research centre. SUBJECTS: 599 healthy women aged 27 to 72 and 125 women with low bone mass aged 55-77 had bone mineral density measured once in the cross sectional study. 136 women aged 45-54 were followed up for 18 years in the longitudinal study. MAIN OUTCOME MEASURES: Bone mineral density measured at the lumbar spine, hip, and forearm and rate of bone loss at different times over 18 years in relation to vitamin D receptor genotype as defined by the endonucleases ApaI, EsmI, and TaqI. RESULTS: Vitamin D receptor genotype was not related to bone mineral density at any site. The maximum difference between homozygotes was 1.3% (P = 0.33, n = 723). Women with low bone mineral density had almost the same genotype frequencies as the women with normal bone mineral densities. Vitamin D receptor genotype was not related to early postmenopausal bone loss from age 51 to 53 (mean (SD) total loss at the lower forearm -3.6% (3.6%)), late postmenopausal bone loss from age 63 to 69 (at the hip-6.2% (8.7%)), or to long term postmenopausal loss from age 51 to 69 (at the lower forearm-24.5% (11.4%)). CONCLUSION: Common allelic variation at the vitamin D receptor locus as defined by the endonucleases ApaI, EsmI, and TaqI is related neither to bone mineral density nor to the rate of bone loss in healthy postmenopausal Danish women.