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.