Association between Frailty and the Self-reported Inability to Immediately Open a Polyethylene Terephthalate Bottle Cap in Older Japanese Adults

Abstract

Objective: This study aimed to clarify the association between frailty and the self-reported inability to immediately open a polyethylene terephthalate (PET) bottle cap. Methods: This cross-sectional study included 427 participants aged 73 and 78 years in City A, Japan. Frailty was assessed using the Kihon Checklist (KCL), and PET bottle cap opening ability was surveyed using a mailed questionnaire. The participants were divided into Immediately Open and Cannot-Immediately Open groups. The frailty status and KCL scores were compared between the groups. Multivariate analysis was used to investigate the association between frailty and the PET bottle cap-opening pattern. The possibility of screening frailty based on the Immediately/Cannot-Immediately Open classification was analyzed using a receiver operating characteristic (ROC) curve. Results: The number of frailty in the Cannot-Immediately Open group was significantly greater than the expected count compared to the robust and pre-frailty groups (P <0.001). Total KCL scores differed significantly between the Immediately Open group (3.2 ± 3.1) and the Cannot-Immediately Open group (5.7 ± 4.1) (P <0.001). The Cannot-Immediately Open group showed significantly higher scores in 5 of the 7 domains and a higher proportion of 1-point scores in 15 of the 25 KCL items. Individuals in the Cannot-Immediately Open group were associated with frailty (β = 2.03; odds ratio = 7.62; P <0.001). The ROC analysis revealed a sensitivity and specificity of 50.0% and 81.0%, respectively (area under the curve = 0.65; P <0.001). Conclusions: The self-reported inability to open a PET bottle cap immediately may be a moderate screening tool for frailty and is associated with many frailty factors.