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Background: Osteoarthritis is the most common form of arthritis, with knee osteoarthritis being the leading cause of lower extremity disability among older adults in the US. There are no treatments available to prevent the structural pathology of osteoarthritis. Because of vitamin K's role in regulating skeletal mineralization, it has potential to be a preventative option for osteoarthritis. We therefore examined the relation of vitamin K to new-onset radiographic knee osteoarthritis and early osteoarthritis changes on magnetic resonance imaging (MRI)., Methods: Subjects from the Multicenter Osteoarthritis (MOST) Study had knee radiographs and MRI scans obtained at baseline and 30 months later, and plasma phylloquinone (vitamin K) measured at baseline. We examined the relationship of subclinical vitamin K deficiency to incident radiographic knee osteoarthritis and MRI-based cartilage lesions and osteophytes, respectively, using log binomial regression with generalized estimating equations, adjusting for potential confounders., Results: Among 1180 participants (62% women, mean age 62±8 years, mean body mass index 30.1±5.1 kg/m(2)), subclinical vitamin K deficiency was associated with incident radiographic knee osteoarthritis (risk ratio [RR] 1.56; 95% confidence interval [CI], 1.08-2.25) and cartilage lesions (RR 2.39; 95% CI, 1.05-5.40) compared with no deficiency, but not with osteophytes (RR 2.35; 95% CI, 0.54-10.13). Subclinically vitamin K-deficient subjects were more likely to develop osteoarthritis in one or both knees than neither knee (RR 1.33; 95% CI, 1.01-1.75 and RR 2.12; 95% CI, 1.06-4.24, respectively)., Conclusion: In the first such longitudinal study, subclinical vitamin K deficiency was associated with increased risk of developing radiographic knee osteoarthritis and MRI-based cartilage lesions. Further study of vitamin K is warranted given its therapeutic/prophylactic potential for osteoarthritis., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Purpose: Although chronic obstructive pulmonary disease (COPD) has a major impact on physical health, the specific impact of COPD on physical functional limitations has not been characterized clearly. We aimed to elucidate the physical functional limitations that are directly attributable to COPD compared to a matched referent group without the condition., Methods: We used the Function, Living, Outcomes, and Work (FLOW) cohort study of adults with COPD (n=1202) and referent subjects matched by age, sex, and race (n=302) to study the impact of COPD on the risk of a broad array of functional limitations using validated measures: lower extremity function (Short Physical Performance Battery [SPPB]), submaximal exercise performance (Six Minute Walk Test [SMWT]), standing balance (Functional Reach Test), skeletal muscle strength (manual muscle testing with dynamometry), and self-reported functional limitation (standardized item battery). Multivariate analysis was used to control for confounding by age, sex, race, height, educational attainment, and cigarette smoking., Results: COPD was associated with poorer lower extremity function (mean SPPB score decrement for COPD vs referent -1.0 points; 95% CI, -1.25 to -0.73 pts) and less distance walked during the SMWT (-334 feet; 95% CI, -384 to -282 ft). COPD also was associated with weaker muscle strength in every muscle group tested, including both the upper and lower extremities (P<.0001 in all cases) and with a greater risk of self-reported functional limitation (OR 6.4; 95% CI, 3.7 to 10.9)., Conclusions: A broad array of physical functional limitations were specifically attributable to COPD. COPD affects a multitude of body systems remote from the lung.