Vitamin D and estrogen receptor polymorphisms and bone mineral changes in postpartum women

BsmI restriction fragment length polymorphism (RFLP) of the vitamin D recep tor (VDR) gene and PvuII RFLPs of the estrogen receptor (ER) gene and their relation to changes in areal bone mineral density (BMD) were examined in 4 3 healthy postpartum Finnish women aged 31.3 (SD 4.7) years. BMD was measur ed by dual energy X-ray absorptiometry at lumbar spine, right femoral neck, and dominant distal radius immediately after delivery, 1 month after resum ption of menses, and 1 year thereafter. The RFLPs were represented as Bb (B smI) and Pp (PvuII), the capital letters denoting the absence of and the sm all letters the presence of the restriction sites. The frequency of VDR all eles was as follows: bb (20.9%), Bb (60.5%), and BE (18.6%), and that of ER alleles was pp (39.5%), Pp (51.2%), and PP (9.3%). Altogether, BMD decreas ed significantly during postpartum amenorrhea at all sites [the mean bone l oss ranging from -1.2 (SD 3.6)% at the distal radius to -3.7 (2.9)% at the femoral neck], and increased after resumption of menses [the 1-year follow- up BMD values ranging from -1.0 (2.4)% at the femoral neck to +3.3 (4.0)% a t the lumbar spine as compared with baseline]. No obvious genotype-related differences were found between these changes. These results suggest that th e BsmI and PvuII polymorphisms may not have substantial influence on BMD ch anges postpartum.