Purpose: To evaluate the independent and combined associations of cardiorespiratory fitness (CRF) and muscular strength (MS) with arterial stiffness (AS), a strong predictor of cardiovascular disease, in older adults.
Methods: This cross-sectional study included 405 older adults (mean age, 72 yr). Cardiorespiratory fitness was assessed by time (s) to complete a 400-m walking test and MS by maximal handgrip strength (kg). Carotid-femoral pulse wave velocity was used to assess AS. High AS was defined as a pulse wave velocity of ≥10 m·s, a previously established threshold for increased cardiovascular risk. Poisson regression was used to calculate prevalence ratios (PR) and 95% confidence intervals (CI) of having high AS across sex-specific tertiles of CRF and MS. Muscular strength and CRF were further dichotomized into either "weak" or "unfit" (lower one third for each), or "strong" or "fit" (upper two thirds for each) to investigate the combined associations of CRF and MS with high AS. All analyses were adjusted for potential confounders, including MS for CRF and CRF for MS.
Results: Sixty-nine (17%) participants had high AS. Compared with lower CRF, PR (95% CI) of having high AS were 0.53 (0.30-0.95) and 0.69 (0.38-1.23) for middle and upper CRF, respectively. Compared with lower MS, PR (95% CI) of having high AS were 0.81 (0.49-1.34) and 0.52 (0.29-0.92) for middle and upper MS, respectively. In the joint analysis, compared with the "unfit and weak" group, PR (95% CI) of having high AS were 0.72 (0.38-1.35), 0.58 (0.29-1.16), and 0.46 (0.25-0.85) for "unfit and strong," "fit and weak," and "fit and strong" groups, respectively.
Conclusions: Higher levels of CRF and MS were independently associated with lower (healthier) levels of AS in older adults.