The influence of age on change in intramuscular adipose tissue of the quadriceps is remarkable in older inpatients aged 85 and over

<h2>Summary</h2><h3>Purpose</h3> This study aimed to examine the influence of age on change in intramuscular adipose tissue of the quadriceps in older inpatients. <h3>Methods</h3> This prospective study included 191 older inpatients (aged ≥65 years). We divided the participants into the following three age groups: 65–74 years (n = 29), 75–84 years (n = 80), and ≥85-years (n = 82). Intramuscular adipose tissue of the quadriceps was assessed based on quadriceps echo intensity. Greater intramuscular adipose tissue was indicated by higher echo intensity. The change in quadriceps echo intensity was calculated by subtracting this baseline value from the value at discharge. For comparing the changes in quadriceps echo intensity among the three groups, analysis of covariance adjusted for confounding factors was conducted. Multiple linear regression analysis was used to determine whether age was independently and significantly related to changes in quadriceps echo intensity. <h3>Results</h3> Change in quadriceps echo intensity of the aged ≥85-year group (−0.4 ± 12.1 [a.u.]) was significantly higher than that of the 65–74-year group (−6.4 ± 15.0 [a.u.]). Age was significantly and independently related to change in quadriceps echo intensity (β = 0.148, <i>P</i> = 0.036). <h3>Conclusions</h3> The results of this study indicate that higher age in older inpatients may negatively affect the decrease of intramuscular adipose tissue of the quadriceps. Especially, this trend is observed in older inpatients aged 85 and over.