Effectiveness of comparing calf circumference with neck circumference regarding their association with skeletal muscle indices in Japanese nursing home residents.

[Purpose] This study aimed to determine the association between calf and neck circumferences and skeletal muscle indices, including phase angle, among Japanese nursing home residents. [Participants and Methods] A cross-sectional study of a single nursing home was conducted, in which 72 nursing home residents (aged 85.9 ± 8.4 years, mean ± standard deviation [SD]) were enrolled. Calf and neck circumferences were measured using a measuring tape, and body composition assessment was measured using a bioimpedance device. [Results] The age- and sex-adjusted partial correlation coefficient showed that calf circumference exhibited a significantly high correlation with all body composition parameters; however, neck circumference exhibited a significantly low correlation with body fat percentage only. The calf circumference had a higher correlation coefficient than the neck circumference with all body composition items, except for body fat percentage. [Conclusion] This study showed that phase angle and muscle mass were associated with calf circumference, but not with neck circumference, in Japanese nursing home residents. Therefore, calf circumference is important in clinical evaluations as a potential screening tool for nursing home residents with various diseases.

Phase angle as a prognostic factor for one-year mortality in geriatric health service facility residents.

[Purpose] The present study aimed to investigate the association of phase angle with the continuing activities of residents in a geriatric health service facility for one year. We compared the phase angle among current residents in a geriatric health service facility with those who died within one year. [Participants and Methods] This one-year prospective observational study included 149 residents who entered a geriatric health service facility. We divided participants into two groups: an over one-year survival group and a death within one year group. The receiver operating characteristic curves were created to determine the sensitivity and specificity for predicting one-year mortality based on the phase angle. [Results] The phase angle was significantly higher in the one-year survival group than in the death within one year group and was independently and significantly associated with one-year mortality using binomial logistic regression analysis. The phase angle was shown to have predictive power (based on the area under the receiver operating characteristic curve). Based on the calculation for identifying one-year survival, the optimal cut-off value for the phase angle was 2.95° (area under the receiver operating characteristic curve=0.76, sensitivity 55.6%, specificity 83.3%). [Conclusion] The phase angle may contribute to the prognosis of one-year mortality for residents of geriatric health service facilities.

Association between age and phase angle in "old" and "super-old" nursing home residents.

[Purpose] We aimed to clarify the characteristics of age-related changes based on the body composition data of old and super-old nursing home residents. [Participants and Methods] This cross-sectional study included 53 female nursing home residents aged 75 years and above (mean age: 89.4 years; standard deviation: 5.6 years). They were divided into the old and super-old groups. The old group consisted of 24 participants aged between 75 and 89 years (mean age: 84.4 years; standard deviation: 3.7 years). The super-old group consisted of 29 participants aged 90 years and above (mean age: 93.5 years; standard deviation: 2.7 years). The parameters such as phase angle, skeletal muscle mass index, skeletal muscle mass, body fat percentage, body mass index, and Barthel index were examined in the two groups. The relationship between age and phase angle was determined, and the partial correlation coefficient was analyzed using the items for which a significant difference was found between the two groups as adjustment variables. [Results] The overall phase angle was 3.2 degrees, and that of the super-old group alone was 2.6 degrees. Age-related difference was observed in the phase angle and Barthel index. A significant correlation of -0.53 was observed between age and phase angle. The Barthel index-adjusted partial correlation coefficient between age and phase angle was -0.35. [Conclusion] The results of this study indicated that phase angle is an indicator of physical condition associated with aging in female nursing home residents aged 75 to 100 years.