Impact of Sex on the Association between Flexibility and Arterial Stiffness in Older Adults.

Background and Objectives : Flexibility is one of the most important physical fitness parameters in the geriatric population. Brachial-ankle pulse wave velocity (baPWV) is a measure of systemic arterial stiffness. However, data on the association between flexibility and arterial stiffness in the older adult population are limited. Therefore, we aim to investigate this association by using the sit-and-reach test (SRT) and measuring baPWV. Materials and Methods : We reviewed data from the 2014-2015 Korean Institute of Sports Science Fitness Standards Project. Individuals older than 65 years with SRT and baPWV data were included. A generalized linear regression analysis was conducted to assess the association between flexibility and arterial stiffness. Multiple relevant confounding factors were adjusted. Results : A total of 615 individuals were included in the analysis. The mean age of the male and female participants was 71.44 ± 4.42 and 70.64 ± 4.13 years, respectively. The mean SRT result was 6.58 ± 9.97 and 18.04 ± 7.48 cm, respectively. After multivariable adjustment among the male participants, the higher SRT result tertiles were inversely associated with baPWV (β (95% confidence interval): 3.11-11.00 cm, -74.45 (-140.93, -8.55); ≥11.01 cm, -108.17 (-177.65, -38.70)) in comparison with the lowest tertile. The female participants did not show any significant correlation between the SRT result and baPWV. Conclusions : Our results suggest an inverse association between trunk flexibility and systemic arterial stiffness, expressed as the SRT result and baPWV, respectively, in older Korean men but no association in older Korean women. Sex differences might influence the association between flexibility and arterial stiffness in the older adult population.