Association between upper limb muscle quality and knee osteoarthritis in dynapenia: an observational cross-sectional study.

Neurological and skeletal muscle properties are suggested causes of dynapenia. This study aimed to evaluate the relationship between upper limb muscle quality (grip strength/upper extremity muscle mass) and knee osteoarthritis in dynapenia, and to identify dynapenia-associated factors. Elderly individuals who responded to a public call for screening in Wakasa Town, Fukui Prefecture between June 2019 and November 2021 were included. The analysis included 433 participants (304 women aged 76.0 ±â€…7.1 years). Examination comprised (consecutively) a basic interview, physical function measurement, body composition measurement, and explanation of results. Dynapenia was observed in 67 patients. Binomial logistic regression analysis revealed that age, upper limb muscle quality score, and knee osteoarthritis were independent factors for dynapenia. Receiver operating characteristic analysis of the relationship between dynapenia and upper limb muscle quality showed an area under the curve of 0.806 (95% confidence interval: 0.658-0.953) for men (cut-off value, 14.3 kg/kg) and 0.849 for women (95% confidence interval: 0.858-0.968; cut-off value, 14.0 kg/kg). In conclusion, age, upper limb muscle quality, and knee osteoarthritis were independent factors of dynapenia. We demonstrated that upper limb muscle quality has good accuracy in detecting dynapenia in both men and women.

Can bone mass measured via bioelectrical impedance analysis be used to diagnose sarcopenia?

The simplification of diagnostic criteria is critical to promoting interventions for sarcopenia. This study aimed to evaluate the relationship between sarcopenia and bone mass [measured by bioelectrical impedance analysis (BIA)], as well as to identify new indicators associated with this disease. Basic interviews and measurement of physical function were performed on 474 community-dwelling older adults (aged 77.1 ±â€…7.6 years), including older adult patients with sarcopenia, in Wakasa Town, Fukui Prefecture. The findings led to 363, 71, and 40 participants being classified as 'normal', 'pre-sarcopenia', and 'having sarcopenia', respectively. An Ordinal Logistic Regression Analysis showed that age, bone mass phase angle (lower limb), Fat-free Mass Index, and leg muscle score were aggravating factors for sarcopenia in both men and women. A receiver operating characteristic analysis of bone mass and sarcopenia status showed that the area under the curve and cut-off value, as well as its sensitivity and specificity, in men were 0.915 [95% confidence interval (CI): 0.853-0.977], 2.2 kg, 81%, and 87%, respectively, and 0.913 (95% CI: 0.858-0.968), 1.6 kg, 91%, and 88%, respectively, in women. This study revealed that the BIA method of measuring bone mass has excellent accuracy in detecting sarcopenia in both males and females.

The role of fat indices as factors leading to sarcopenia in older adults residing in underpopulated areas.

Simplifying the diagnostic criteria for sarcopenia is key to establishing effective interventions. Herein, we aimed to clarify novel diagnostic factors. We calculated novel fat indices [total fat index (TFI) and limb fat index (LFI)] and clarified factors leading to pre-sarcopenia and sarcopenia in 594 enrolled older adults. Physical measurements [height, weight, body mass index (BMI), gait speed, grip strength, and skeletal muscle mass] were performed. Sarcopenia was determined using established diagnostic criteria (pre-sarcopenia, n = 102; sarcopenia, n = 42). Age was associated with sarcopenia status. BMI, TFI, and LFI were lower in patients with pre-sarcopenia and sarcopenia. Logistic regression analysis showed the following odds ratios (ORs) for pre-sarcopenia: BMI [OR: 0.787, 95% confidence interval (CI): 0.7-0.885], LFI (OR: 0.589, 95% CI: 0.402-0.863), and age (OR: 1.06, 95% CI: 1.02-1.1). ORs for sarcopenia (vs pre-sarcopenia) were as follows: LFI (OR: 50.6, 95% CI: 10.2-250.0), age (OR: 1.1, 95% CI: 1.0-1.2), and BMI (OR: 0.418, 95% CI: 0.28-0.608). Our findings contribute to informing medical guidelines.

Dose-responsive alteration in hepatic lipid peroxidation and retinol metabolism with increasing dietary beta-carotene in iron deficient rats.

Phosphatidylcholine hydroperoxide (PCOOH) levels are increased in the iron-deficient rat liver. We investigated the antioxidative effect of dietary beta-carotene and altered retinol metabolism in iron-deficient rats. Experiment 1: Male Wistar-strain rats were divided into six groups and fed a control diet, an iron-deficient diet, and iron-deficient diets with four different levels of dietary beta-carotene. The PCOOH concentration in the iron-deficient rat liver was decreased by supplementation with dietary beta-carotene. However, the beta-carotene dose response was not related to antioxidative potency. Hepatic and plasma beta-carotene concentrations were increased by iron deficiency. The hepatic retinol concentration was increased while the plasma retinol concentration was decreased in iron-deficient rats. Experiment 2: Male Wistar-strain rats were divided into two groups, with one group receiving a control diet with beta-carotene and the other an iron-deficient diet with beta-carotene. Intestinal iron was decreased and intestinal beta-carotene was unchanged in iron-deficient rats. The intestinal beta-carotene conversion ratio and beta-carotene cleavage enzyme activity were decreased in iron-deficient rats. Dietary beta-carotene played the role of an antioxidant in hepatic lipid peroxidation in the iron-deficient state, but there was no dose dependency. Moreover, intestinal beta-carotene cleavage and hepatic retinol release appear to be altered in iron-deficient rats.