2015 Volume 19 Issue 3 Pages 214-221
Skeletal muscle mass decreasing and muscle weakness can cause long-term care needs for elderly people. The relationship between skeletal muscle status and muscles relevant to oral function has been little reported. Therefore, the aim of the present study was to survey skeletal muscle status, oral function, and the relationship between the two in community-dwelling elderly people.
Twenty-four community-dwelling elderly from two elderly associations in N city, T prefecture enrolled in the present survey (3 males, 21 females; mean age, 77.0±5.0 years). Skeletal muscle index (SMI) was used to assess skeletal muscle mass, grasping power to assess skeletal muscle strength. Oral function was evaluated in terms of jaw-opening force, diadochokinesis, the repetitive saliva swallowing test (RSST), and the modified water swallowing test (MWST). Correlations between parameters were analyzed using Spearman's correlation coefficient. Consequently stepwise regression analysis was performed with jaw-opening force as objective variable and SMI, grasping force, age and sex as explanatory variables.
The subjects were divided into two groups according to standards for grasping force: healthy and muscle weakness (male: ＜26 kgw; female: ＜18 kgw). Parameters were statistically compared between the two groups using the Mann-Whitney U test.
There were statistical relationships between SMI and jaw-opening force (r＝0.578, p＝0.003), grasping force and jaw-opening force (r＝0.640, p＝0.001), grasping force and the number of diadochokinetic movement of /ta/ (r＝0.447, p＝0.029). As a result of stepwise regression analysis, SMI was a factor that affects jaw-opening force.
In the muscle weakness group, jaw-opening force was less than the value in the healthy group ( p＝0.011). It is reasonable that an overall decrease in muscle mass would evoke decreases in muscle strength in both the extremities and the jaw-opening muscles.
We confirmed significant relationships between skeletal muscle mass, skeletal muscle strength, and oral function (i.e., jaw-opening force and tongue skilled movement) in Japanese community-dwelling elderly.
