title: Dietary calcium and serum 25-hydroxyvitamin D status in relation to BMD among U.S. adults.
abstract: A higher calcium intake is still the primary recommendation for the prevention of osteoporosis, whereas vitamin D deficiency is often not addressed. To study the relative importance of dietary calcium intake and serum 25-hydroxyvitamin D [25(OH)D] status in regard to hip BMD, 4958 community-dwelling women and 5003 men >/=20 yr of age from the U.S. NHANES III population-based survey were studied. Calcium supplement users and individuals with a prior radius or hip fracture were excluded. We calculated standardized means for BMD by quartiles of sex-specific calcium intake for three 25(OH)D categories (<50, 50-74, and 75+ nM) among men and women, separately controlling for other important predictors of BMD. A higher calcium intake was significantly associated with higher BMD (p value for trend: p = 0.005) only for women with 25(OH)D status <50 nM, whereas calcium intake beyond the upper end of the lowest quartile (>566 mg/d) was not significantly associated with BMD at 25(OH)D concentrations >50 nM. Among men, there was no significant association between a higher calcium intake beyond the upper end of the lowest quartile (626 mg/d) and BMD within all 25(OH)D categories. Among both sexes, BMD increased stepwise and significantly with higher 25(OH)D concentrations (<50, 50-74, 75+ nM; p value for trend: women < 0.0001; men = 0.0001). Among men and women, 25(OH)D status seems to be the dominant predictor of BMD relative to calcium intake. Only women with 25(OH)D concentrations <50 nM seem to benefit from a higher calcium intake.
authors.affiliation: Centre on Aging and Mobility, University of Zurich, Zurich, Switzerland. heikeabischoff@aol.com
authors.forename: Heike A
authors.initials: HA
authors.lastname: Bischoff-Ferrari
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Kiel
authors.forename: Bess
authors.initials: B
authors.lastname: Dawson-Hughes
authors.forename: John E
authors.initials: JE
authors.lastname: Orav
authors.forename: Ruifeng
authors.initials: R
authors.lastname: Li
authors.forename: Donna
authors.initials: D
authors.lastname: Spiegelman
authors.forename: Thomas
authors.initials: T
authors.lastname: Dietrich
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology*; D002136:Calcium, Dietary / Q000008:administration & dosage*; D004032:Diet / Q000706:statistics & numerical data; D005260:Female; D006615:Hip / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D014481:United States; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D002136:Calcium, Dietary; D014807:Vitamin D; C104450:25-hydroxyvitamin D