B-vitamin status and bone mineral density and risk of lumbar osteoporosis in older females in the United States

• Published in: The American journal of clinical nutrition Vol. 102; no. 3; pp. 687 - 694
• Main Authors: Bailey, Regan L, Looker, Anne C, Lu, Zhaohui, Fan, Ruzong, Eicher-Miller, Heather A, Fakhouri, Tala H, Gahche, Jaime J, Weaver, Connie M, Mills, James L
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Nutrition, Inc 01.09.2015
• Subjects: Absorptiometry, Photon; Aged; Biomarkers; Biomarkers - blood; Bone Density; Creatinine - blood; Cross-Sectional Studies; Dietary supplements; Female; Folic Acid - blood; Homocysteine - blood; Humans; Methylmalonic Acid - blood; Middle Aged; Nutrition Surveys; Nutritional Status; Osteoporosis; Osteoporosis - blood; Osteoporosis - epidemiology; Risk Factors; United States - epidemiology; Vitamin B Complex - blood; United States; United States > US; homocysteine; NHANES; DXA; bone turnover markers; osteoporosis
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.115.108787

Previous data suggest that elevated serum total homocysteine (tHcy) may be a risk factor for bone fracture and osteoporosis. Nutritional causes of elevated tHcy are suboptimal B-vitamin status. To our knowledge, this is the first nationally representative report on the relation of B vitamins and bone health from a population with folic acid fortification. The purpose of this analysis was to examine the relation between B-vitamin status biomarkers and bone mineral density (BMD), risk of osteoporosis, and biomarkers of bone turnover. We examined the relation of tHcy, methylmalonic acid (MMA), and serum/red blood cell folate and total-body and lumbar spine BMD in women aged ≥50 y participating in the NHANES 1999-2004 (n = 2806), a nationally representative cross-sectional survey. These are the only years with concurrent measurement of tHcy and whole-body dual-energy X-ray absorptiometry. We also examined B-vitamin biomarkers relative to bone turnover markers, bone alkaline phosphatase, and urinary N-terminal cross-linked telopeptide of type I collagen in a 1999-2002 subset with available data (n = 1813). In comparison with optimal concentrations, women with elevated tHcy were older with lower serum vitamin B-12, red blood cell folate, and dietary micronutrient intakes and had significantly higher mean ± SE markers of bone turnover (bone alkaline phosphatase: 15.8 ± 0.59 compared with 14.0 ± 0.25 μg/L; urinary N-terminal cross-linked telopeptide of type I collagen: 48.2 ± 2.9 compared with 38.9 ± 0.90 nmol bone collagen equivalents per mmol creatinine/L). Elevated MMA (OR: 1.88; 95% CI: 1.10, 3.18) and tHcy (OR: 2.17; 95% CI: 1.14, 4.15) were related to increased risk of lumbar osteoporosis. When examined as a continuous variable, tHcy was negatively associated, serum folates were positively associated, and MMA and vitamin B-12 were not significantly associated with lumbar and total-body BMD. In this nationally representative population of older US women with high exposure to B vitamins through food fortification and dietary supplements, only elevated tHcy and MMA were independently associated with risk of lumbar spine osteoporosis.