title: Vitamin D status and sex hormone binding globulin: determinants of bone turnover and bone mineral density in elderly women.
abstract: To examine the relation of the vitamin D status and the remaining estrogen activity with bone turnover and bone mineral density (BMD) in elderly women, BMD was measured at both hips using dual-energy X-ray absorptiometry and at the distal radius using single photon absorptiometry, in 330 healthy women aged 70 and over. Vitamin D metabolites, sex hormone binding globulin (SHBG), PTH(1-84), osteocalcin, alkaline phosphatase, and hydroxyproline and calcium excretion in 2 h fasting urine were measured. Multiple linear regression was used to adjust for potential confounders. In 65% of the women, serum 25(OH)D was below 30 nmol/l. Only values below a threshold for 25(OH)D were negatively related to serum PTH(1-84) (p = 0.02, threshold at 25 nmol/l) and to osteocalcin levels (p = 0.04, threshold at 30 nmol/l). BMD of the femoral neck and trochanter was positively related to serum 25(OH)D (left neck p = 0.001) with thresholds at 30 nmol/l whereas the distal radius was not (p = 0.32). Serum PTH was negatively related to BMD at all measurement sites (all p < 0.001). Serum SHBG, an inverse measure of estrogen activity, was positively related to osteocalcin levels (p = 0.004) and the urinary hydroxyproline/creatinine ratio (p = 0.002) and negatively related to the BMD of the trochanter (left trochanter p = 0.02) and the distal radius (p = 0.001). We conclude that in elderly women, serum 25(OH)D levels below 30 nmol/l are associated with secondary hyperparathyroidism and increased bone turnover. SHBG is positively related to bone turnover.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institute for Research in Extramural Medicine (EMGO-Institute) Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: M E
authors.initials: ME
authors.lastname: Ooms
authors.forename: P
authors.initials: P
authors.lastname: Lips
authors.forename: J C
authors.initials: JC
authors.lastname: Roos
authors.forename: W J
authors.initials: WJ
authors.lastname: van der Vijgh
authors.forename: C
authors.initials: C
authors.lastname: Popp-Snijders
authors.forename: P D
authors.initials: PD
authors.lastname: Bezemer
authors.forename: L M
authors.initials: LM
authors.lastname: Bouter
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000097:blood; D015519:Bone Density / Q000502:physiology*; D001846:Bone Development / Q000502:physiology; D002118:Calcium / Q000652:urine; D005260:Female; D005269:Femur / Q000502:physiology; D005272:Femur Neck / Q000502:physiology; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D006909:Hydroxyproline / Q000652:urine; D006961:Hyperparathyroidism / Q000097:blood / Q000209:etiology; D016014:Linear Models; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D011884:Radius / Q000502:physiology; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism*; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood
chemical_list: D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D012738:Sex Hormone-Binding Globulin; D015675:Osteocalcin; D014807:Vitamin D; D000469:Alkaline Phosphatase; D006909:Hydroxyproline; D002118:Calcium