在宅高齢嚥下障害は低栄養・下気道感染の危険因子

在宅高齢者で嚥下障害は低栄養と下気道感染の危険因子であるという論文を紹介します。

Serra-Prat M, Palomera M, Gomez C, Sar-Shalom D, Saiz A, Montoya JG, Navajas M, Palomera E, Clavé P. Oropharyngeal dysphagia as a risk factor for malnutrition and lower respiratory tract infection in independently living older persons: a population-based prospective study. Age Ageing. 2012 May;41(3):376-81.

リサーチクエスチョンは、

P：70歳以上の在宅高齢者で（254人、平均78歳）
E：嚥下障害のある方は（V-VSTで評価）
C：嚥下障害のない方と比較して
O：低栄養（MNAで評価）と下気道感染（臨床記録）が多い
D：コホート研究

です。

volume-viscosity swallow test (V-VST)は下記のブログを参照してください。日本でこれをそのまま行うことはないと思います。

V-VSTによる嚥下スクリーニング
http://rehabnutrition.blogspot.jp/2011/05/v-vst.html

結果ですが、抄録しか読めていないので嚥下障害のある方が何人かは不明です。嚥下障害のある方では嚥下障害のない方と比較して、1年後に低栄養もしくは低栄養のおそれありの方が有意に多く、下気道感染も有意に多い（40％対21.8％）でした。

これより在宅高齢者で嚥下障害は低栄養と下気道感染の危険因子であるという結論です。在宅高齢者では定期的に嚥下障害の有無をスクリーニング、治療すべきとしています。

在宅高齢者で嚥下障害と栄養障害の有病割合を調査の上、嚥下障害と健康障害（下気道感染）の関連を明らかにした点で、意味があると考えます。今後は日本で同様な研究を行い、在宅でどのような嚥下・栄養などの介入を行えば、健康障害を少なくできるかが課題です。

Abstract
OBJECTIVE: to assess the role of oropharyngeal dysphagia (OD) as a risk factor for malnutrition and/or lower respiratory tract infection (LRTI) in the independently-living population of 70 years and over.

DESIGN: a population-based cohort study. Subjects and setting: persons 70 years and over in the community (non-institutionalised) were randomly selected from primary care databases.

MEASUREMENTS: the volume-viscosity swallow test (V-VST) was administered by trained physicians at baseline to identify subjects with clinical signs of OD and impaired safety or efficacy of swallow. At the one year follow-up visit, hand grip, functional capacity (Barthel score), nutritional status (mini nutritional assessment, MNA) and LRTI (clinical notes) were assessed.

RESULTS: two hundred and fifty-four subjects were recruited (46.5% female; mean age, 78 years) and 90% of them (227) were re-evaluated one year later. Annual incidence of 'malnutrition or at risk of malnutrition' (MNA <23.5) was 18.6% in those with basal signs of OD and 12.3% in those without basal signs of OD (P = 0.296). However, prevalent cases of 'malnutrition or at risk of malnutrition' at follow up were associated with basal OD (OR = 2.72; P = 0.010), as well as with basal signs of impaired efficacy of swallow (OR = 2.73; P = 0.015). Otherwise, LRTI's annual incidence was higher in subjects with basal signs of impaired safety of swallow in comparison with subjects without such signs (40.0 versus 21.8%; P = 0.030; OR = 2.39).

CONCLUSIONS: OD is a risk factor for malnutrition and LRTI in independently living older subjects. These results suggest that older persons should be routinely screened and treated for OD to avoid nutritional and respiratory complications.

腎細胞がん術後の肥満は生存期間改善

腎細胞がん術後患者では、肥満は生存期間改善と術後合併症増加と関連するという論文を紹介します。

Åse J. Rogde, et al: Obesity is associated with an improved cancer-specific survival, but an increased rate of postoperative complications after surgery for renal cell carcinoma. Scandinavian Journal of Urology and Nephrology, Posted online on April 25, 2012. (doi:10.3109/00365599.2012.678382)

抄録しか読めていないので詳細不明ですが、タイトル通りの結論です。肥満はいくつかのがんで発症率を高めたり、消化器がんの死亡率を高めるリスクですが、この研究では予後良好となっています。おそらく筋肉量、悪液質の有無・程度の関連だと思います。

Abstract
Objective. This study aimed to assess the impact of preoperative body mass index (BMI) on postoperative complications, cancer-specific survival (CSS) and overall survival (OS) in patients operated for renal cell carcinoma (RCC).

Material and methods. The study included 397 patients with BMI values, who underwent surgery for RCC between 1 January 1997 and 31 December 2010. Obese patients (BMI > 30 kg/m2) were compared to non-obese patients (BMI < 30 kg/m2) in regard to CSS and OS. A Cox proportional hazard model was used for the multivariate survival analyses. The mean age of the patients was 62.1 years. There were 259 males (65%) and 325 patients (82%) were non-obese. Mean BMI was 26 kg/m2.

Results. In the total material, CSS was 94.7% for obese patients and 74.8% for non-obese patients (p = 0.06). The obese group had significantly better CSS in univariate analysis for presumed radically treated disease (pT1–3N0M0). Obesity was a significant protective prognostic factor in multivariate analysis. An accelerating protective effect for CSS was found with increasing levels of BMI. In regard to OS, no difference was found between the two groups. Obese patients had a significantly lower age, and a higher rate of diabetes mellitus, hypertension and incidental detection. Obese patients had a significantly higher total incidence of postoperative complications, but not surgery-related complications.

Conclusions. In this material, increasing BMI was associated with improved CSS for presumed radically treated patients. However, obese patients had a higher total rate of postoperative complications.

がんの臨床栄養と身体組成：追加図

先程紹介した、がんの臨床栄養と身体組成に関するレビュー論文ですが、追加の図を紹介します。やはりこの論文から学ぶことは多いので、ぜひ読まれることをおすすめします。

Nathalie Jacquelin-Ravela, Claude Pichard. Clinical nutrition, body composition and oncology: A critical literature review of the synergies. Critical Reviews in Oncology/Hematology http://dx.doi.org/10.1016/j.critrevonc.2012.02.001

これはがんで推奨される栄養介入を図にしたものです。

一次栄養評価として、身体組成（L3-4レベルの腹部CTをがんの診断で撮影していれば評価、およびBIA）、検査値（CRP、プレアルブミン、アルブミン、浸透圧）、BMI・健常時体重・現体重、NRS（Nutritional Risk Screening）があります。

その結果、介入が必要であれば一部の場合のみ静脈栄養、他は経腸栄養としています。また、フォローアップとして、NRSを週1回、身体組成（BIAと可能ならCT）と検査値を3週間に1回としています。

BIAを一次栄養評価でもフォローアップでも必須にしていることが特徴的です。信頼性、妥当性のある栄養スクリーニングもしくは栄養アセスメントとともに、身体組成を定期的に評価していくのが、リハ栄養でも当たり前の時代が来るかもしれません。

がんの臨床栄養と身体組成

がんの臨床栄養と身体組成に関するレビュー論文を紹介します。

Nathalie Jacquelin-Ravela, Claude Pichard. Clinical nutrition, body composition and oncology: A critical literature review of the synergies. Critical Reviews in Oncology/Hematology http://dx.doi.org/10.1016/j.critrevonc.2012.02.001

図のように悪液質とサルコペニアの違いを明確に解説していますし、悪液質の定義はEPCRC、ESPEN、Evansらの3つを紹介しています。わかりやすくて読む価値のあるレビュー論文だと考えます。まだ全部読めていませんが…。

単なる体重減少だけでなく身体組成の結果に基づいて栄養状態を評価すべきです。身体組成は体表面積よりも化学療法時の薬剤の量を決めるのに正確です。サルコペニアは抗がん剤毒性の唯一有意な予測因子です。身体組成はがん治療に影響を与えます。

Abstract

Purpose of the research
Review the oncology and clinical nutrition literature to highlight the synergies between those two subjects. This review focuses on diagnostic of lean body wasting and the recent improvements in measuring body composition to monitor the response to nutrition during optimal oncology treatment.

Principal results Nutrition support in cancer patients has made major progresses. A variety of advanced tools allow monitoring and explaining weight loss, body composition changes and metabolic alterations. Body composition is more accurate than body surface area to determine chemotherapeutic drug dosing. As with any therapeutic approach, clinical nutrition has a better risk-benefit ratio if implemented when indicated rather than used routinely. Body composition measurements are helpful for a better understanding of the host-tumor interactions during cancer treatment and nutrition support.

Major conclusions Nutrition support based on body composition analysis may significantly contribute to optimize current oncology treatment and clinical outcomes.

Highlights ► Body composition should replace weight loss to define the nutritional status. ► Obesity and cachexia may occur simultaneously. ► Sarcopenia is the only significant predictor of chemotoxicity. ► Body composition techniques have a demonstrated positive impact in cancer treatment. ► Nutrition is not a routine care, needs to be patient-specific and fine-tuned.

日本人の身長補正頸囲と睡眠時無呼吸

日本人の身長で補正した頸囲と、補正頸囲が閉塞型睡眠時無呼吸症候群の重症度に与える影響をみた論文を紹介します。

Kawaguchi Y, Fukumoto S, Inaba M, Koyama H, Shoji T, Shoji S, Nishizawa Y. Different impacts of neck circumference and visceral obesity on the severity of obstructive sleep apnea syndrome. Obesity (Silver Spring). 2011 Feb;19(2):276-82.

この論文の特記すべき点は、日本人の頸囲（頸部周囲長、首回り、NC）の身長による補正式（頸囲を身長で割ったものです）が提示されていることです。海外では先行研究として、身長で補正した％頸囲が以下の式が示されています。

percentage of predicted NC = 100 × NC (cm)/(0.055 × height (cm) + 31) (%)

この補正式の元は、以下の論文です。
Davies RJ, Stradling JR. The relationship between neck circumference,
radiographic pharyngeal anatomy, and the obstructive sleep apnoea
syndrome. Eur Respir J 1990;3:509–514.

この論文では、肥満ではない日本人86人からまず頸囲の予測式を提示しています。
predicted NC (cm) = 0.21 × height (cm) + 3.4; r = 0.626, P < 0.0001

次に、身長で補正した頸囲は以下の％頸囲と極めて強い相関を認めました。
percentage of predicted NC = 100 × NC cm/ (0.21 × H cm + 3.4) (r = 0.997, P < 0.0001)

なお頸囲の計測については輪状甲状膜cricothyroid membraneのレベルで行っています。

身長で補正した頸囲のほうが頸囲単独よりも、BMI、体脂肪、内臓脂肪との関連が強く、身長で補正した頸囲で検討するほうが適切と判断しています。その上で身長で補正した頸囲と内臓脂肪は、独立して睡眠時無呼吸と関連しているという結果を出しています。

頸囲は肥満マーカーとして有用という報告があります。一方、頸囲もしくは頸囲を身長で割った数値がいくつ以下なら、低栄養や嚥下障害と関連しているという結果も出せるかもしれません。日本人の頸囲、身長補正頸囲、％頸囲による嚥下評価、栄養評価を行う際に参考になります。

Abstract
Our aim was to investigate the significance of neck circumference (NC) on the presence and severity of obstructive sleep apnea (OSA) syndrome independent of visceral fat (VF) obesity. A total of 219 subjects with suspected OSA underwent a complete polysomnography (PSG) study, along with the measurement of NC, and total body fat (TF) and VF levels (VFLs) measured by bioelectrical impedance analysis. We proposed NC divided by height (NC/H) as the simple index for height-corrected NC in Japanese subjects. NC/H exhibited a significantly stronger correlation than NC per se with BMI (r = 0.781 vs. 0.675, P = 0.0178), TF (r = 0.531 vs. 0.156, P < 0.0001), and VF (r = 0.819 vs. 0.731, P = 0.0203), indicating that NC/H is a better indicator of visceral obesity than NC per se. Interestingly, despite the strong correlation between NC/H and VFL, VFL was significantly associated with the apnea-hypopnea index (AHI) ≥ 5, ≥ 15, and ≥ 30, but not with ≥ 40 or ≥ 50, whereas NC/H was significantly associated with higher AHI values, i.e., AHI ≥ 50 but not with lower AHI value. Furthermore, multiple regression analyses revealed that VFL and NC/H were independently associated with the square root of AHI (AHI(0.5)) levels in obese and nonobese patients, respectively. In conclusion, NC is associated with the severity of OSA independently of visceral obesity, especially in nonobese patients.

頸部力変換器による嚥下評価

頸部力変換器による努力嚥下と非努力嚥下の違い：臨床でのフィードバックシステム発展への影響に関する論文を紹介します。

Coulas VL, Smith RC, Qadri SS, Martin RE.　Differentiating effortful and noneffortful swallowing with a neck force transducer: implications for the development of a clinical feedback system.　Dysphagia. 2009 Mar;24(1):7-12.

図のような頸部力変換器を使用して、嚥下に関連したの頸囲の変化を評価することで、努力嚥下と非努力嚥下の違いを判断できるかという研究です。若年健常女性を対象に実施した結果、陽性、陰性ともピーク電圧が、努力嚥下で有意に高かったです。これをバイオフィードバックに応用できる可能性があります。

この論文も頸囲と嚥下機能に関する内容ではないかと思って読んでみました。サルコペニアによる嚥下障害の方であれば、努力嚥下であってもピーク電圧は低くなる可能性があります。これをサルコペニアの嚥下障害の診断に利用する方法もあるかもしれません。

Abstract

This study sought to determine whether effortful saliva swallows could be differentiated from habitual, noneffortful saliva swallows on the basis of swallow-related changes in neck circumference in humans. Gender differences in swallow-related neck circumference were examined as a secondary question. Twenty-seven healthy adults (14 females; mean age = 26.6 years, SD = 3.9 years) participated in two experimental runs (run duration = 10 min) during which they produced single trials of three visually cued tasks in random order: effortful saliva swallowing, saliva swallowing, and a control task involving repetitive apposition of the dominant thumb and index finger. Neck and ribcage circumference were simultaneously collected from the output of force transducers positioned around the neck and ribcage, respectively. The primary outcome variables were the positive and negative voltage peak amplitudes associated with changes in neck circumference during single-swallow trials. Effects of the swallowing task on positive and negative voltage peaks were examined with separate two-way analysis of variance procedures. Results indicated that both positive (F = 6.49, p < 0.05) and negative (F = 12.05, p neck. This type of physiologic recording may have potential as a biofeedback technique in training dysphagic patients on the effortful swallow maneuver.

年齢と二軸嚥下加速度計信号の相関

身体計測や年齢性別と二軸嚥下加速度計信号は相関する：正準相関分析という論文を紹介します。

Hanna F, Molfenter SM, Cliffe RE, Chau T, Steele CM. Anthropometric and demographic correlates of dual-axis swallowing accelerometry signal characteristics: a canonical correlation analysis. Dysphagia. 2010 Jun;25(2):94-103.

二軸嚥下加速度計信号が、年齢・性別や身体計測（身長・体重・体脂肪率・頸囲・下顎長）によって系統的変動を生じるかどうかを調査しています。対象は年齢・性別にばらつきを持たせた健常者50人です。二軸嚥下加速度計信号は唾液嚥下と水分嚥下5回ずつで計測しました。

二軸嚥下加速度計信号は唾液嚥下と水分嚥下5回ずつで計測しました。変動、振幅分布の歪度と尖度、信号記憶、信号エネルギー、最大エネルギー尺度、最大振幅といった信号を調べました（この辺詳しくないので、日本語訳がいい加減です）。

正準相関分析が何かは、私もよく理解できていませんが、興味のある方は下記のスライドシェアを参照してください。
http://www.slideshare.net/akisatokimura/090608-cca
結果ですが、唾液嚥下と水分嚥下の上下軸では有意な直線関係を認めませんでした。前後軸では、振幅分布の尖度と信号記憶が年齢と有意に相関していました。これより身体計測ではなく年齢が二軸嚥下加速度計信号と関連を認めるかもしれないという結論です。

嚥下機能と頸囲（首回り）に関心があったので、この論文を読んでみました。ただ、頸囲は下顎長や体重と強い相関があったため、正準相関分析には含まれていませんでした。そのため、頸囲と二軸嚥下加速度計信号による嚥下機能に関連があるかどうかは不明でした。

頸囲（neck circumference）と嚥下機能をみた論文は、私が調べた範囲ではあまりありませんでした。むしろ睡眠時無呼吸症候群との関連、肥満・BMIのマーカーに関する論文が多かったです。心血管疾患のリスクや脳卒中の死亡率と関連という報告もありました。

ただ、いずれにしても頸囲が太いことに問題があるという論文がほとんどです。頸囲が細いことに問題があることについて触れた論文はあまり見つかりませんでした。頸囲が細い＝サルコペニア＝嚥下障害については、やはり自分たちで研究しなければいけないようです。

Abstract
Swallowing accelerometry has been proposed as a potential minimally invasive tool for collecting assessment information about swallowing. The first step toward using sounds and signals for dysphagia detection involves characterizing the healthy swallow. The purpose of this article is to explore systematic variations in swallowing accelerometry signals that can be attributed to demographic factors (such as participant gender and age) and anthropometric factors (such as weight and height). Data from 50 healthy participants (25 women and 25 men), ranging in age from 18 to 80 years and with approximately equal distribution across four age groups (18-35, 36-50, 51-65, 66 and older) were analyzed. Anthropometric and demographic variables of interest included participant age, gender, weight, height, body fat percent, neck circumference, and mandibular length. Dual-axis (superior-inferior and anterior-posterior) swallowing accelerometry signals were obtained for five saliva and five water swallows per participant. Several swallowing signal characteristics were derived for each swallowing task, including variance, amplitude distribution skewness, amplitude distribution kurtosis, signal memory, total signal energy, peak energy scale, and peak amplitude. Canonical correlation analysis was performed between the anthropometric/demographic variables and swallowing signal characteristics. No significant linear relationships were identified for saliva swallows or for superior-inferior axis accelerometry signals on water swallows. In the anterior-posterior axis, signal amplitude distribution kurtosis and signal memory were significantly correlated with age (r = 0.52, P = 0.047). These findings suggest that swallowing accelerometry signals may have task-specific associations with demographic (but not anthropometric) factors. Given the limited sample size, our results should be interpreted with caution and replication studies with larger sample sizes are warranted.