Relationship between klotho and physical function in healthy aging

Abstract

Epidemiological studies have reported a strong association between circulating Klotho and physical function; however, the cohorts were comprised of older adults with multiple comorbidities. Herein, we examined the relationship between Klotho and physical function in a community-based cohort of healthy adults. In this cross-sectional study, serum Klotho was measured in 80 adults who visited the Musculoskeletal Function, Imaging, and Tissue Resource Core of the Indiana Center for Musculoskeletal Health. Participants (n = 20, 10 [50%] men per group) were chosen into four age groups: 20-34, 35-49, 50-64, and ≥ 65 years, and were further grouped based on performance (low vs. high) on grip strength and chair stand tests. Klotho levels were lower in the ≥ 65 years group (703.0 [189.3] pg/mL; p = 0.022) and the 50-64 years group (722.6 [190.5] pg/mL; p = 0.045) compared to 20-34 years (916.1 [284.8] pg/mL). No differences were observed in Klotho between the low and high performers. The ≥ 65 years group walked a shorter distance during the 6-min walk test (6MWT) compared to 20-34 years (p = 0.005). Klotho was correlated with age (p < 0.001), body fat (p = 0.037), and 6MWT distance (p = 0.022). Klotho levels decline as early as the fifth decade of life, potentially before the onset of age-related impairment in exercise capacity.

Figure 1

Differences in serum Klotho between low and high performers. P values are displayed for comparison between performance category in each age group. No differences were observed in serum Klotho levels between the high performers and low performers in any age group.

Figure 2

Associations between serum Klotho and age, body composition, and physical function indices. (A) Age. (B) Body fat %. (C) Appendicular lean mass. (D) Score on the physical function domain of the National Institutes of Health Patient-Reported Outcomes Measurement Information System computerized adaptive test (PROMIS PF CAT). (E) Distance walked during 6-min walk test. (F) Usual gait speed. (G) Time to complete 5 chair stands. (H) Grip strength. Serum Klotho was significantly associated with age, body fat %, and distance walked in the 6-min walk test.