Relationship between tongue strength, lip strength, and nutrition-related sarcopenia in older rehabilitation inpatients: a cross-sectional study

OBJECTIVE The objective of this study was to clarify the relationship between tongue strength, lip strength, and nutrition-related sarcopenia (NRS). PATIENTS AND METHODS A total of 201 older inpatients aged ≥65 years (70 men, median age: 84 years, interquartile range: 79-89 years) consecutively admitted for rehabilitation were included in this cross-sectional study. The main factors evaluated were the presence of NRS diagnosed by malnutrition using the Mini-Nutrition Assessment - Short Form, sarcopenia based on the criteria of the Asian Working Group for Sarcopenia, tongue strength, and lip strength. Other factors such as age, sex, comorbidity, physical function, cognitive function, and oral intake level were also assessed. RESULTS In all, 78 (38.8%) patients were allocated to the NRS group, and 123 (61.2%) patients were allocated to the non-NRS group. The median tongue strength and lip strength (interquartile range) were significantly lower in the NRS group (tongue: 22.9 kPa [17.7-27.7 kPa] and lip: 7.2 N [5.6-9.8 N]) compared with the non-NRS group (tongue: 29.7 kPa [24.8-35.1 kPa] and lip: 9.9 N [8.4-12.3 N], P<0.001 for both). Multivariable logistic regression analysis showed that NRS was independently associated with tongue strength (odds ratio [OR] =0.93, 95% confidence interval [CI] 0.87-0.98, P=0.012) and lip strength (OR =0.76, 95% CI 0.66-0.88, P<0.001), even after adjusting for age, sex, comorbidity, physical function, cognitive function, and oral intake level. CONCLUSION The likelihood of occurrence of NRS decreased when tongue strength or lip strength increased. Tongue strength and lip strength may be important factors for preventing and improving NRS, regardless of the presence of low oral intake level in older rehabilitation inpatients.