食事パターンと転倒による骨折の関連

今日は、日本人高齢者で食事パターンが転倒による骨折と関連するという論文を紹介します。

Monma et al: Dietary patterns associated with fall-related fracture in elderly Japanese: a population based prospective study. BMC Geriatrics 2010, 10:31

下記のHPで全文を見ることができます。

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2895588/pdf/1471-2318-10-31.pdf

食事内容から、食事パターンをThe Vegetable pattern（野菜が多い食事）、The Meat pattern（肉が多い食事）、The Traditional Japanese pattern（伝統的な和食に近い食事）の3つに分類しています。

この3群で転倒による骨折が多いか少ないかを前向きに調査した結果、肉が多い食事群で転倒による骨折が少なく、野菜が多い食事で転倒による骨折が多いという結果でした。ただ、統計学的有意差はありますが95％信頼区間は1に近いので、実際にはあまり差はない偶然の可能性もあります。

転倒による骨折はinsurance claim records（レセプトですよね）で評価して、例えば交通外傷による骨折は、転倒による骨折には含めないようにしています。ただ、厳密には区別できない場合もあるかもしれません。

なお単変量解析では、転倒による骨折は高齢者に多く、BMIやエネルギー摂取量には有意差はありませんでした。

この論文だけで転倒による骨折を防ぐために肉をたくさん食べましょう、と指導する気には私はなりません。ただ、野菜ばかりを好んで食べる高齢者には肉や魚も食べるように話したほうがよいのかもしれません。

転倒予防と栄養（特にビタミンD）の関連は無視できませんが、やはり運動療法、補装具、環境整備、薬剤調整などと組み合わせて行うべきだろうと思います。

Abstract
Background: Diet is considered an important factor for bone health, but is composed of a wide variety of foods containing complex combinations of nutrients. Therefore we investigated the relationship between dietary patterns and fall-related fractures in the elderly.

Methods: We designed a population-based prospective survey of 1178 elderly people in Japan in 2002. Dietary intake was assessed with a 75-item food frequency questionnaire (FFQ), from which dietary patterns were created by factor analysis from 27 food groups. The frequency of fall-related fracture was investigated based on insurance claim records from 2002 until 2006. The relationship between the incidence of fall-related fracture and modifiable factors, including dietary patterns, were examined. The Cox proportional hazards regression model was used to examine the relationships between dietary patterns and incidence of fall-related fracture with adjustment for age, gender, Body Mass Index (BMI) and energy intake.

Results: Among 877 participants who agreed to a 4 year follow-up, 28 suffered from a fall-related fracture. Three dietary patterns were identified: mainly vegetable, mainly meat and mainly traditional Japanese. The moderately confirmed (see statistical methods) groups with a Meat pattern showed a reduced risk of fall-related fracture (Hazard ratio = 0.36, 95% CI = 0.13 - 0.94) after adjustment for age, gender, BMI and energy intake. The Vegetable pattern showed a significant risk increase (Hazard ratio = 2.67, 95% CI = 1.03 - 6.90) after adjustment for age, gender and BMI. The Traditional Japanese pattern had no relationship to the risk of fall-related fracture.

Conclusions: The results of this study have the potential to reduce fall-related fracture risk in elderly Japanese. The results should be interpreted in light of the overall low meat intake of the Japanese population.