Does BIA Phase Angle Predict Handgrip Strength In Adults With Down Syndrome?

Does BIA Phase Angle Predict Handgrip Strength In Adults With Down Syndrome? BACKGROUND: Adults with Down syndrome (DS) have reduced muscle mass and muscle cell integrity that may contribute to their low muscular performance. Bioelectrical Impedance Analysis (BIA) Phase Angle (PhA) is a raw variable indicative of muscle quality that may be associated with muscular performance in adults with DS. PURPOSE: To examine if BIA PhA predicts handgrip strength in adults with and without DS. METHODS: 19 adults with DS (9 women; age 24 ± 4 years) and 21 adults without DS (non-DS; 10 women; age 24 ± 4 years) underwent measurements of single frequency BIA at 50 kHz and handgrip strength (HG). Differences were assessed with independent T-tests and effect sizes determined as Cohen’s d. Pearson correlation coefficient (r) between PhA and HG were examined, and multiple linear regression was used to examine the effects of sex and disability on the correlation. RESULTS: Large differences were found in mass (DS = 59.8 ± 11.7; non-DS = 71.4 ± 13.2 kg, p = 0.005, d = 0.9) and height (DS = 148 ± 9.6; non-DS = 165 ± 8.1 cm, p < 0.001, d = 1.9), but not in BMI (DS = 27.3 ± 4.8; non-DS = 26 ± 3.6 kg/m2, p = 0.67, d = 0.3). Individuals with DS had lower HG (DS = 15.4 ± 5.7; non-DS = 34.3 ± 10.8 kg, p < 0.001, d = 2.2) and PhA (DS = 6.1 ± 0.6; non-DS = 7.5 ± 0.7°, p < 0.001, d = 2.0) compared to adults without DS. HG and PhA were strongly correlated in the whole sample (r = 0.80, p < 0.001). The regression model indicated that PhA, group, and the PhA-by-group interaction significantly predicted HG (adj R2 = 0.79; p = 0.02). An increase of 1° in PhA was associated with an increase of 3.9 kg in HG (p = 0.02). CONCLUSIONS: BIA PhA is a strong predictor of HG in adults with and without DS. DS-related alteration in muscle quality may contribute to the lower muscle strength in adults with DS. Supported by: Funded by FAPESP (2022/10143-2), FAPESPA (034/2023), and CNPq (200863/2024-0).