Oral Function as a Predictor of Skeletal Muscle Mass Decline in Community-Dwelling Older Adults

Normal oral function is pivotal for maintaining systemic health in older adults as it directly affects skeletal muscle mass and overall physical well-being. Nonetheless, specific oral function-related factors influencing the skeletal muscle mass index (SMI) in healthy older adults remain underexplored.

To identify oral function-related factors associated with a low SMI in healthy, community-dwelling older adults.

This cross-sectional study included 165 healthy older adults aged ≥ 75 years from senior culture centres in Korea. Participants were categorised into normal and low SMI groups, with low SMI defined as < 7.0 kg/m² for men and < 5.7 kg/m² for women. The following oral function-related factors were assessed and classified as normal or abnormal based on standardised evaluation criteria and then compared between the groups: Number of remaining teeth, tongue pressure (TP), masticatory performance (MP), oral diadochokinesis, oral dryness, swallowing function and oral hygiene. Multiple logistic regression was performed to identify factors associated with a low SMI.

The prevalence of a low SMI was 19.4% (n = 32). After adjusting for sociodemographic variables, reduced MP (odds ratio, 3.899; 95% confidence interval, 1.103-13.779) and reduced TP (odds ratio, 3.416; 95% confidence interval, 1.035-11.270) were identified as factors associated with a low SMI.

This study demonstrated that a reduction in MP and TP contributes to a low SMI in healthy older adults, highlighting the importance of oral function in maintaining systemic health and promoting healthy ageing.