Swallowing‐Related Time Measured by a Neck‐Worn Electronic Stethoscope and Its Associations With Age, Sex, and Masticatory Function in Community‐Dwelling Older Adults

INTRODUCTION: Objective assessment of swallowing function in community-dwelling older adults remains challenging. A neck-worn electronic stethoscope (NWES) can measure swallowing-related time noninvasively. This study aimed to examine age- and sex-related differences in NWES-derived swallowing-related time metrics and their relationship with masticatory function. METHODS: Older adults from the Itabashi Longitudinal Study on Aging in 2024 were included. Swallowing-related time was measured using NWES as pharyngeal clearance time (PCT), representing the duration of pharyngeal swallowing during water swallowing, and oral processing and swallowing time (OPST), reflecting the duration from oral processing to swallowing completion during cracker ingestion. Masticatory function was assessed using a gummy jelly test. RESULTS: Four hundred and sixty-two participants (mean age 76.1 ± 3.4 years) were included. Median (interquartile range) PCT was 0.88 (0.70-1.01) s in men and 0.75 (0.61-0.92) s in women; corresponding OPST values were 34.51 (28.89-42.93) and 43.46 (34.33-54.09) s, respectively. PCT was significantly longer in men, whereas OPST was significantly longer in women. OPST correlated with age in men (r = 0.17) and women (r = 0.20). Masticatory function was not significantly associated with PCT in either sex. After adjustment for age, body mass index, number of functional teeth, stroke history, and PCT, higher masticatory function scores were significantly associated with shorter OPST only in men (B = -0.67). CONCLUSION: NWES-derived PCT and OPST showed different associations with age and masticatory function, with OPST associated with age in both sexes and with masticatory function in men. PCT and OPST may offer practical approaches for evaluating oral processing performance in older adults.