MNAとADL（Barthel Index）の横断研究

MNAとADL（Barthel Index）の関連を調べた横断研究を紹介します。

Mirarefin M, et al: Predicting the value of the Mini Nutritional Assessment (MNA) as an indicator of functional ability in older Iranian adults (Kahrizak elderly study).
J Nutr Health Aging. 2011 Mar;15(3):175-80.

MNAは23.5以下（低栄養の恐れあり、もしくは低栄養：17以下の場合）と24以上で分けています。MNAとBIで有意な相関がありましたが、r = 0.199なので、決定係数としては約4％となります。

Barthel Indexのカットオフポイントは、男性の場合91.5点、女性の場合83.5点で、これ以下の場合、MNAの低栄養の恐れありと関連があります。

横断研究なので栄養状態がADLに影響を与えるのか、ADLが栄養状態に影響を与えるのか、両方なのかはわかりません。また決定係数が約4％ですので、ADLの残りの96％は栄養以外の要素で決まるということになります。統計学的には有意でも臨床的にはやや微妙な結果です。

MNAを17未満と17以上で分けたほうが、よりADLとの関連が出るのではと私は思っています。

Abstract
OBJECTIVE: We aimed to investigate the appropriateness of the Mini Nutritional Assessment (MNA) in predicting functional ability in older adults.

DESIGN: Cross-sectional study.

SETTING: Participants were recruited from the Kahrizak Charity Foundation (KCF).

MEASUREMENTS: Nutritional and ability status were examined using the MNA and the Barthel Index (BI). Participants were divided according to MNA (≤ 23.5 and > 23.5).

RESULTS: Two hundred and thirty-five ≥ 60-year-old subjects were studied. The MNA and BI were positively correlated (r = 0.199; P = 0.001). The optimal cut-off point for BI with the highest sensitivity and specificity derived from the ROC curve was approximately 91.5 for males and 83.5 for females. The BI was significantly associated with MNA (odds ratio (OR): 1.89; 95% CI: 1.17-3.05, P = 0.009), mobility (OR: 6.39; 95% CI: 3.43-11.89, P < 0.001), consuming ≥ 2 servings of fruit and vegetables (OR: 2.27; 95% CI: 1.09-4.72, P = 0.02) and self-view of nutritional status (OR: 4.15; 95%CI: 1.26-13.63, P = 0.01). The sensitivity (62.9% in males; 68.2% in females) and specificity (51.4% in males and 52.9% in females) of these cut-off points justifies the appropriateness of the MNA for determining functional ability.

CONCLUSION: The MNA is potentially able to verify functional status among the elderly (as BI ≥ 91.5 with those of < 91.5 in males and ≥ 83.5 with those of < 83.5 in females) of KCF. It is suggested that this relationship should be further studied in a larger prospective population-based study.