Vitamin K Status and Lower Extremity Function in Older Adults: The Health Aging and Body Composition Study.

BACKGROUND: While low vitamin K status has been associated with several chronic diseases that can lead to lower extremity disability, it is not known if low vitamin K status is associated with worse lower extremity function. METHODS: Vitamin K status was measured according to plasma phylloquinone (vitamin K1) and dephosphorylated-uncarboxylated MGP (dp-ucMGP) in 1,089 community-dwelling older adults (mean ± SD age =74±3 years; 67% female). Lower extremity function was assessed using the short physical performance battery (SPPB), gait speed, and isokinetic leg strength. Linear regression and mixed models were used to determine the cross-sectional and longitudinal associations between vitamin K status and functional outcome measures. RESULTS: Cross-sectionally, higher plasma phylloquinone was associated with better SPPB scores and 20-m gait speed (p ≤ .05). After 4-5 years, those with ≥1.0nM plasma phylloquinone (the concentration achieved when recommended intakes are met) had better SPPB scores (p = .03) and 20-m gait speed (p < .05). Lower plasma dp-ucMGP (reflective of better vitamin K status) was associated with better SPPB scores and leg strength cross-sectionally (p ≤ .04), but not longitudinally. Neither measure of vitamin K status was associated with walking endurance or with the rate of decline in function. CONCLUSION: Older adults with higher vitamin K status had better physical performance scores at baseline, but data are less consistent longitudinally. Since lower extremity disability is a common consequence of multiple chronic diseases for which a role of vitamin K has been suggested, future studies are needed to determine if vitamin K supplementation could improve function in those with vitamin K insufficiency and clarify underlying mechanism(s).

Correlates of use of antifracture therapy in older women with low bone mineral density.

BACKGROUND: Guidelines exist for treatment of low bone mineral density (BMD). Little is known about patient characteristics associated with use of treatment. OBJECTIVES: To determine patient-related correlates of medication use following screening dual x-ray absorptiometry (DXA) of older adults. DESIGN: Secondary analysis of a prospective cohort study. SETTING: Pittsburgh, PA and Memphis, TN. PARTICIPANTS: Community-dwelling women between the ages 70 and 79 years enrolled in the Health, Aging, and Body Composition (Health ABC) Study. MEASUREMENTS: Risk factors for fracture and BMD of the hip were assessed at baseline. Patients and their community physicians were supplied the results of the DXA scan. Prescription and over-the-counter medication use was collected at annual exams for 2 years. RESULTS: Of 1,584 women enrolled in Health ABC, 378 had an indication for antifracture therapy and were not receiving such treatment at baseline. By the second annual follow-up examination, prescription antiresorptive medication was reported in 49 (13.0%), whereas 65 (17.2%) received calcium and/or vitamin D supplementation. In adjusted models, the strongest predictor for use of any antifracture medicine was presence of osteoporosis [vs osteopenia, odds ratio (OR), 2.9 (1.7 to 4.7)], white race [OR, 2.6 (1.5 to 4.8)], and receipt of the flu shot [OR, 2.2 (1.3 to 3.8)]. Neither a history of falls nor prior fracture was associated with use of antifracture medications. CONCLUSION: Even when physicians of study participants were provided with DXA scan results, 70% of older high-functioning women with an indication for therapy did not start or remain on an antifracture therapy. Substantial room for improvement exists in fracture prevention following a diagnosis of low BMD-especially among women with a history of falls, prior fractures, and among black women.