Michelle Shardell1,2, Anne R Cappola3, Jack M Guralnik2, Gregory E Hicks4, Stephen B Kritchevsky5, Eleanor M Simonsick6, Luigi Ferrucci6, Richard D Semba7, Nancy Chiles Shaffer6, Tamara Harris6, Gudny Eiriksdottir8, Vilmundur Gudnason8, Mary Frances Cotch9, Eric Orwoll10, Kristine E Ensrud11, Peggy M Cawthon12. 1. Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA. 2. Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA. 3. University of Pennsylvania School of Medicine, Philadelphia, PA, USA. 4. Department of Physical Therapy, University of Delaware, Newark, DE, USA. 5. Sticht Center for Healthy Aging and Alzheimer's Prevention, Wake Forest School of Medicine, Winston-Salem, NC, USA. 6. National Institute on Aging, Bethesda, MD, USA. 7. Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA. 8. Icelandic Heart Association, Reykjavik, Iceland. 9. National Eye Institute, Intramural Research Program, Division of Epidemiology and Clinical Applications, Bethesda, MD, USA. 10. Oregon Health & Science University, Portland, OR, USA. 11. University of Minnesota Department of Medicine and Division of Epidemiology, Minneapolis, MN, USA. 12. California Pacific Medical Center Research Institute, San Francisco, CA, USA.
Abstract
BACKGROUND: Threshold serum 25-hydroxyvitamin D [25(OH)D] concentrations for extraskeletal outcomes are uncertain and could differ from recommendations (20-30 ng/mL) for skeletal health. OBJECTIVES: We aimed to identify and validate sex-specific threshold 25(OH)D concentrations for older adults' physical function. METHODS: Using 5 large prospective, population-based studies-Age, Gene/Environment Susceptibility-Reykjavik (n = 4858, Iceland); Health, Aging, and Body Composition (n = 2494, United States); Invecchiare in Chianti (n = 873, Italy); Osteoporotic Fractures in Men (n = 2301, United States); and Study of Osteoporotic Fractures (n = 5862, United States)-we assessed 16,388 community-dwelling adults (10,376 women, 6012 men) aged ≥65 y. We analyzed 25(OH)D concentrations with the primary outcome (incident slow gait: women <0.8 m/s; men <0.825 m/s) and secondary outcomes (gait speed, incident self-reported mobility, and stair climb impairment) at median 3.0-y follow-up. We identified sex-specific 25(OH)D thresholds that best discriminated incident slow gait using machine learning in training data (2/3 cohort-stratified random sample) and validated using the remaining (validation) data and secondary outcomes. RESULTS: Mean age in the cohorts ranged from 74.4 to 76.5 y in women and from 73.3 to 76.6 y in men. Overall, 1112/6123 women (18.2%) and 494/3937 men (12.5%) experienced incident slow gait, 1098/7011 women (15.7%) and 474/3962 men (12.0%) experienced incident mobility impairment, and 1044/6941 women (15.0%) and 432/3993 men (10.8%) experienced incident stair climb impairment. Slow gait was best discriminated by 25(OH)D <24.0 ng/mL compared with 25(OH)D ≥24.0 ng/mL in women (RR: 1.29; 95% CI: 1.10, 1.50) and 25(OH)D <21.0 ng/mL compared with 25(OH)D ≥21.0 ng/mL in men (RR: 1.43; 95% CI: 1.01, 2.02). Most associations between 25(OH)D and secondary outcomes were modest; estimates were similar between validation and training datasets. CONCLUSIONS: Empirically identified and validated sex-specific threshold 25(OH)D concentrations for physical function for older adults, 24.0 ng/mL for women and 21.0 ng/mL for men, may inform candidate reference concentrations or the design of vitamin D intervention trials.
BACKGROUND: Threshold serum 25-hydroxyvitamin D [25(OH)D] concentrations for extraskeletal outcomes are uncertain and could differ from recommendations (20-30 ng/mL) for skeletal health. OBJECTIVES: We aimed to identify and validate sex-specific threshold 25(OH)D concentrations for older adults' physical function. METHODS: Using 5 large prospective, population-based studies-Age, Gene/Environment Susceptibility-Reykjavik (n = 4858, Iceland); Health, Aging, and Body Composition (n = 2494, United States); Invecchiare in Chianti (n = 873, Italy); Osteoporotic Fractures in Men (n = 2301, United States); and Study of Osteoporotic Fractures (n = 5862, United States)-we assessed 16,388 community-dwelling adults (10,376 women, 6012 men) aged ≥65 y. We analyzed 25(OH)D concentrations with the primary outcome (incident slow gait: women <0.8 m/s; men <0.825 m/s) and secondary outcomes (gait speed, incident self-reported mobility, and stair climb impairment) at median 3.0-y follow-up. We identified sex-specific 25(OH)D thresholds that best discriminated incident slow gait using machine learning in training data (2/3 cohort-stratified random sample) and validated using the remaining (validation) data and secondary outcomes. RESULTS: Mean age in the cohorts ranged from 74.4 to 76.5 y in women and from 73.3 to 76.6 y in men. Overall, 1112/6123 women (18.2%) and 494/3937 men (12.5%) experienced incident slow gait, 1098/7011 women (15.7%) and 474/3962 men (12.0%) experienced incident mobility impairment, and 1044/6941 women (15.0%) and 432/3993 men (10.8%) experienced incident stair climb impairment. Slow gait was best discriminated by 25(OH)D <24.0 ng/mL compared with 25(OH)D ≥24.0 ng/mL in women (RR: 1.29; 95% CI: 1.10, 1.50) and 25(OH)D <21.0 ng/mL compared with 25(OH)D ≥21.0 ng/mL in men (RR: 1.43; 95% CI: 1.01, 2.02). Most associations between 25(OH)D and secondary outcomes were modest; estimates were similar between validation and training datasets. CONCLUSIONS: Empirically identified and validated sex-specific threshold 25(OH)D concentrations for physical function for older adults, 24.0 ng/mL for women and 21.0 ng/mL for men, may inform candidate reference concentrations or the design of vitamin D intervention trials.
Authors: Rosemary L Schleicher; Maya R Sternberg; David A Lacher; Christoher T Sempos; Anne C Looker; Ramon A Durazo-Arvizu; Elizabeth A Yetley; Madhulika Chaudhary-Webb; Khin L Maw; Christine M Pfeiffer; Clifford Johnson Journal: Natl Health Stat Report Date: 2016-04-25
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Authors: Heike A Bischoff-Ferrari; Bruno Vellas; René Rizzoli; Reto W Kressig; José A P da Silva; Michael Blauth; David T Felson; Eugene V McCloskey; Bernhard Watzl; Lorenz C Hofbauer; Dieter Felsenberg; Walter C Willett; Bess Dawson-Hughes; JoAnn E Manson; Uwe Siebert; Robert Theiler; Hannes B Staehelin; Caroline de Godoi Rezende Costa Molino; Patricia O Chocano-Bedoya; Lauren A Abderhalden; Andreas Egli; John A Kanis; Endel J Orav Journal: JAMA Date: 2020-11-10 Impact factor: 56.272