A 2-year longitudinal study of the relationship between masticatory function and progression to frailty or pre-frailty among community-dwelling Japanese aged 65 and older

BackgroundAn association has recently been reported between frailty and reduced masticatory function; however, the causal relationship remains unclear. ObjectiveThe aim of this study was to clarify the relationship between masticatory function and frailty progression. MethodsAmong 6699 individuals aged 65 and older (mean age 72.85.2years) who were invited to participate in comprehensive medical check-ups, 418 who underwent examinations at the Tokyo Metropolitan Institute of Gerontology in both 2013 and 2015 and who met inclusion criteria were included in this study. Frailty was determined with the Kihon Checklist developed by the Japanese Ministry of Health, Labour and Welfare. The following three masticatory functions were evaluated: occlusal force, mixing ability and subjective chewing ability. The following confounding factors were investigated: age, sex, grip strength, comfortable walking speed, Mini-Mental State Examination (MMSE) score, Self-Rating Depression Scale (SDS) score, skeletal mass index (SMI), number of medications taken and number of remaining teeth. Statistical analysis was performed with binomial logistic regression analysis. ResultsLogistic regression analysis revealed that comfortable walking speed, SDS score, MMSE score and masticatory function were significantly related to progression to frailty or pre-frailty. Of the three masticatory function items evaluated, mixing ability and subjective chewing ability were related to frailty progression. ConclusionOur results confirm that masticatory function was associated with the progression to pre-frailty or frailty among community-dwelling individuals 65years and older over the 2-year period of this longitudinal study. Of the masticatory function items evaluated, mixing ability and subjective chewing ability were associated with frailty progression.