Association of Triglyceride‐Glucose Index and Its Related Parameters With Handgrip Strength Asymmetry

BACKGROUND: The purpose of this study was to explore the associations of the triglyceride-glucose (TyG) index and its clinically relevant derivatives with handgrip strength asymmetry (HGS-A) in a nationally representative cohort of older adults in China. METHODS: Here, we used the data of participants aged between 45 and 80 years who were from wave 2015 of the China Health and Retirement Longitudinal Study (CHARLS). HGS asymmetry was defined as the ratio of nondominant to dominant HGS, categorized into the following four groups: 0.9-1.1 (nonasymmetry), 0.80 ≤ ratio < 0.90 or 1.10 < ratio ≤ 1.20 (mild asymmetry), 0.70 ≤ ratio < 0.80 or 1.20 < ratio ≤ 1.30 (moderate asymmetry) and ratio < 0.70 or ratio > 1.30 (severe asymmetry). Multivariable logistic regression was adopted to assess the association of TyG, TyG-body mass index (TyG-BMI) and TyG-waist-to-height ratio (TyG-WHtR) with HGS asymmetry. RESULTS: A total of 3521 middle-aged and elderly individuals (mean age: 59.74 years; 47.9% male) were included, with the mean TyG of 8.733 ± 0.660, mean TyG-BMI of 243.559 ± 31.120, mean TyG-WHtR of 4.702 ± 0.733. The mean HGS ratio was 0.97 ± 0.16, and participants were classified into the following four groups: nonasymmetry (n = 2174), mild asymmetry (n = 972), moderate asymmetry (n = 237) and severe asymmetry (n = 138). Overall, the prevalence of HGS asymmetry was 38.26%. The prevalence of severe asymmetry increased across TyG quartiles from 3.7% to 4.5% (Q1-Q4, p = 0.018). TyG-WHtR showed increasing prevalence of severe asymmetry from 4.9% to 5.1% across quartiles (p = 0.042). For TyG-BMI, it exhibited an inverse relationship with severe asymmetry prevalence decreasing from 5.3% to 2.4%. Multivariable-adjusted models confirmed that TyG-WHtR demonstrated the strongest effect size with Q2 and Q3 associated with significantly increased odds of asymmetry (OR = 1.507 and 1.437, respectively). TyG-BMI showed a protective effect with higher quartiles associated with reduced odds (Q2-Q4 OR range: 0.973-0.984). CONCLUSIONS: Higher levels of TyG-WHtR and lower levels of TyG-BMI are both associated with a higher prevalence and severity of HGS asymmetry in middle-aged and older Chinese adults.