Higher undercarboxylated to total osteocalcin ratio is associated with reduced physical function and increased 15‐year falls‐related hospitalizations:​ the Perth Longitudinal Study of Aging Women

Smith, Cassandra<sup>1,2</sup>; Lewis, Joshua R.<sup>3,4,5</sup>; Sim, Marc<sup>3,5</sup>; Lim, Wai H.<sup>5,6</sup>; Lim, Ee Mun<sup>7,8</sup>; Blekkenhorst, Lauren C.<sup>3,5</sup>; Brennan‐Speranza, Tara C.<sup>9,10</sup>; Adams, Leon<sup>5,11</sup>; Byrnes, Elizabeth<sup>7</sup>; Duque, Gustavo<sup>2,12</sup>; Levinger, Itamar<sup>1,2</sup>; Prince, Richard L.<sup>5</sup>

Affiliations

¹Institute for Health and Sport (IHES), Victoria University, Melbourne, Australia

²Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St. Albans, Australia

³School of Medical and Health Sciences, Edith Cowan University, Perth, Australia

⁴Centre for Kidney Research, Children’s Hospital at Westmead, School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia

⁵Medical School, University Western Australia, Perth, Australia

⁶Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, Australia

⁷Department of Clinical Biochemistry, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Perth, Australia

⁸Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Australia

⁹Department of Physiology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, Australia

¹⁰School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia

¹¹Department of Hepatology, Sir Charles Gairdner Hospital, Nedlands, Australia

¹²Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, Australia

Abstract and keywords

Evidence from animal models suggests that undercarboxylated osteocalcin (ucOC) is involved in muscle mass maintenance and strength. In humans, the ucOC to total (t)OC ratio may be related to muscle strength and perhaps physical function and falls risk, but data are limited. We tested the hypothesis that ucOC and ucOC/tOC ratio are associated with muscle function (muscle strength and physical function) in older women and 15‐year falls‐related hospitalizations. Serum tOC and ucOC were assessed in 1261 older women (mean age 75.2 ± 2.7 years) forming the Perth Longitudinal Study of Aging Women (1998 to 2013). Timed‐up‐and‐go (TUG) and grip strength were assessed at baseline and at 5 years. Falls‐related hospitalizations (14.5‐year follow‐up) were captured by the Hospital Morbidity Data Collection, via the Western Australian Data Linkage System. At baseline, women with higher ucOC/tOC ratio (quartile 4) had slower TUG performance compared with quartile 1 (~0.68 seconds, p < .01). Grip strength and 5‐year change of TUG and grip were not different (p > .05) between quartiles. Fear of falling limiting house, outdoor, and combined activities was significantly different across quartiles (p < .05). Higher ucOC/tOC was significantly associated with poorer TUG performance at baseline and 5‐year change in performance, increased walking aid use, and fear of falling (all p < .05). Higher ucOC was related to lower grip strength at baseline (p < .05) but not 5‐year change in strength. Those with the highest ucOC/tOC had greater falls‐related hospitalizations (unadjusted log rank, p = .004) remaining significant after adjusting for key variables (hazard ratio [HR] = 1.31, 95% confidence interval [CI] 1.09–1.57, p = .004). We identified a large proportion of older women with high ucOC/tOC ratio who had reduced physical function, including its long‐term decline and increased risk of falls‐related hospitalizations. Early identification of women at higher risk can enable prevention and intervention strategies to occur, reducing risk for injurious falls.

Keywords: AGING; SKELETAL MUSCLE; BONE‐MUSCLE INTERACTIONS; SARCOPENIA

Links

DOI: 10.1002/jbmr.4208

PubMed: 33615560

WoS: 000595223300001

History

Received: 2020-08-15

Revised: 2020-10-20

Accepted: 2020-11-2

Online: 2020-12-3

Cited Works (2)

Year	Entry
2000	Delmas PD, Eastell R, Garnero P, Seibel MJ, Stepan J; Committee of Scientific Advisors of the International Osteoporosis Foundation. The use of biochemical markers of bone turnover in osteoporosis. Osteoporos Int. December 2000;11(suppl 6):S2-S17.
1991	Podsiadlo D, Richardson S. The timed "Up & Go": a test of basic functional mobility for frail elderly persons. J Am Geriatr Soc. February 1991;39(2):142-148.

Cited By (1)

Year	Entry
2022	Smith C, Hiam D, Tacey A, Lin X, Woessner MN, Zarekookandeh N, Garnham A, Chubb P, Lewis JR, Sim M, Herrmann M, Duque G, Levinger I. Higher bone remodeling biomarkers are related to a higher muscle function in older adults: effects of acute exercise. Bone. December 2022;165:116545.