高齢者の咀嚼・嚥下機能と食品嗜好との関連性

【目的】　わが国の高齢化率は上昇を続けており，高齢者の健康寿命への関心も高い．特に食事は楽しみの一つであり，QOL の向上につながる重要因子とされている．咀嚼や嚥下機能が低下すると摂取する食品が制限され，食品嗜好へ影響を与えることが懸念される．しかし，咀嚼機能や嚥下機能など口腔機能と，食品嗜好との関係に着目した研究はみられない．そこで，本研究は，高齢者の咀嚼および嚥下機能と食品嗜好との関連性を明らかにすることを目的とした．
【対象】　徳島大学病院歯科衛生室の65 歳以上の外来受診患者40 名（高齢者群）と，徳島大学歯学部口腔保健学科学生25 名（若年者群）を対象とした．
【方法】　対象者の口腔内状況を確認し，平井らの摂取可能食品質問票の食品35 品目を用いて，食品嗜好スコア（好き/ 嫌い），咀嚼スコア（噛める/ 噛めない），嚥下スコア（飲み込める/ 飲み込めない）に関するアンケートを行い，口腔機能として咀嚼機能はガム咀嚼，前述の咀嚼スコア，嚥下機能は30 秒間の唾液嚥下回数，最大舌圧，水飲みテスト，前述の嚥下スコアを測定し評価した．高齢者群と若年者群の各パラメータにおける2 群間比較を行い，各群における口腔機能と食品嗜好との相関関係を求めて比較した．さらに，食品嗜好スコアと年齢および口腔機能との間における交絡要因の影響を排除するために，ステップワイズ重回帰分散分析を行った．
【結果・考察】　高齢者群のみに30 秒間の唾液嚥下回数と食品嗜好スコアとの間に正の相関が認められた．さらに，多変量解析により，高齢者群のみに嚥下スコアと食品嗜好に，30 秒間の唾液嚥下回数と食品嗜好スコアに正の相関が認められた．高齢者の食品嗜好には，年齢ではなく嚥下機能が影響する可能性が考えられた．
【結論】　高齢者の口腔機能，特に嚥下機能と食品嗜好には関連性があることが示唆された．

Objective: Aging affects the sense of taste, and consequently food preferences change in the elderly. However, preferences might be influenced not only by oral sensory function but also by chewing and swallowing function. This study aimed to clarify the relationship between oral function and food preferences among elderly Japanese.
Materials and Methods: Forty patients (mean age, 74.2 years) of the dental hygiene clinic in Tokushima University Hospital were enrolled in the elderly group. Twenty-five university students (mean age, 21.4 years) were enrolled in the young group.
Food preferences were assessed using a questionnaire on favorite foods among 35 items, based on mastication score (MS). Chewing function was assessed using a xylitol gum-chewing test (Lotte Co., Ltd.) and MS. Swallowing function was assessed using number of saliva swallows in 30 seconds, water swallow test, maximum voluntary tongue pressure (MVTP) and subjective swallowing evaluation (SSE).
The Mann-Whitney U test, X2 test, Spearman’s rank correlation coefficient, and stepwise regression analysis were performed for statistical analyses using SPSS ver.21.
This study was conducted with the approval of the Ethics Committee of Tokushima University Hospital (Approval number: 1378).
Results and Discussion: The scores of the gum-chewing test, MS, number of saliva swallows in 30 seconds, MVTP and SSE of the elderly group were significantly lower than those of the young group. There was a significant correlation between RSST and food preference scores in the elderly group, but not in the young group. Moreover, there were significant correlations between SSE and food preference score, and also between the number of saliva swallows in 30 s and food preference scores in the elderly group with stepwise regression analysis in order to exclude confounding factors between age and oral function.
It is considered that the changes of swallowing function with aging affect food preferences among elderly Japanese.
Conclusion: Our results indicate that swallowing function influences food preferences among elderly Japanese.