title: The association between vitamin D status and parameters for bone density and quality is modified by body mass index.
abstract: The association of vitamin D status with bone mineral density (BMD) and Quantitative Ultrasound measurements (QUS) has been inconsistent in previous studies, probably caused by moderating effects. This study explored (1) the association of vitamin D status with QUS and BMD, and (2) whether these associations were modified by body mass index (BMI), age, gender, or physical activity. Two-independent cohorts of the Longitudinal Aging Study Amsterdam (LASA-I, 1995/1996, aged ≥65; LASA-II, 2008/2009, aged 61-71) and baseline measurement of the B-vitamins for the prevention of osteoporotic fractures (B-PROOF) study (2008-2011, aged 65+) were used. QUS measurements [broadband ultrasound attenuation (BUA) and speed of sound (SOS)] were performed at the calcaneus in all three cohorts (N = 1,235, N = 365, N = 1319); BMD was measured by Dual X-ray absorptiometry (DXA) in B-PROOF (N = 1,162 and 1,192 for specific sites) and LASA-I (N = 492 and 503). The associations of vitamin D status with BUA and BMD were modified by BMI. Only in persons with low-to-normal BMI (<25 kg/m(2)) and serum 25(OH)D <25 nmol/L was associated with lower BUA as compared to the reference group (≥50 nmol/L) in LASA-I and B-PROOF. Furthermore, in LASA-I, these individuals had lower BMD at the hip and lumbar spine. In LASA-II, no associations with BUA were observed. Vitamin D status was not associated with SOS, and these associations were not modified by the effect modifiers tested. The association between vitamin D status and BUA and BMD was modified by BMI in the older-aged cohorts: there was only an association in individuals with BMI <25 kg/m(2).
authors.affiliation: Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, Room A517, 1081 BT, Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Sohl
authors.forename: R T
authors.initials: RT
authors.lastname: de Jongh
authors.forename: K M A
authors.initials: KM
authors.lastname: Swart
authors.forename: A W
authors.initials: AW
authors.lastname: Enneman
authors.forename: J P
authors.initials: JP
authors.lastname: van Wijngaarden
authors.forename: S C
authors.initials: SC
authors.lastname: van Dijk
authors.forename: A C
authors.initials: AC
authors.lastname: Ham
authors.forename: N L
authors.initials: NL
authors.lastname: van der Zwaluw
authors.forename: E M
authors.initials: EM
authors.lastname: Brouwer-Brolsma
authors.forename: N
authors.initials: N
authors.lastname: van der Velde
authors.forename: C P G M
authors.initials: CP
authors.lastname: de Groot
authors.forename: S J
authors.initials: SJ
authors.lastname: te Velde
authors.forename: P
authors.initials: P
authors.lastname: Lips
authors.forename: N M
authors.initials: NM
authors.lastname: van Schoor
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000375:Aging; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D002111:Calcaneus / Q000473:pathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D014807:Vitamin D / Q000378:metabolism*
chemical_list: D014807:Vitamin D