JMBS J Metab Bariatr Surg 2016;5(2):53-61 REVIEW ARTICLE 고려대학교의과대학외과학교실 홍주연, 박성수 Preoperative Nutritional Management of Patients with Morbid Obesity Juyeon Hong, Sungsoo Park Department of Surgery, Korea University College of Medicine, Seoul, Korea Since patients with morbid obesity undergoing bariatric surgery are vulnerable to micronutrient deficiencies, close monitoring and supplementation are necessary. The importance of screening prior to surgery has increased in recent studies; preoperative screening is recommended for thiamine, vitamin B12, vitamin D and calcium, vitamin A, E, K, folic acid, and iron. Though preoperative weight loss (PWL) of more than 10% excess body weight may be beneficial for postoperative weight loss and shorter operative time, insurance-mandated PWL before bariatric surgery is not evidence-based, unsafe, and therefore strongly discouraged. Very-low-calorie diet (VLCD) in liquid form is recommended as a safe and effective way to lose weight preoperatively. Also, screening and correction of eating disorder and psychiatric problems prior to surgery contribute to better outcome. Key Words: Bariatric surgery, Morbid obesity, Preoperative care, Malnutrition, Caloric restriction 서론 고칼로리영양실조 (high calorie malnutrition) 란칼로리는충분하지만열량이없는영양소는부족한상태로서, 현대사회의식이생활에서흔히일어나는문제점이다 [1]. 역설적이게도과다한열량을섭취한비만환자들에서오히려영양결핍현상이정상체중의사람들에비해높은확률로나타나는데, 그기전이명확히밝혀지지는않았지만주요한원인으로고칼로리영양실조를일으키는질낮은식품의섭취가있다 [2-4]. 열량을과잉섭취하고대량영양소 (macronutrient) 가충분해도미량영양소 (micronutrient) 에있어결핍한경우가되려많다는것이다. 비만대사수술을받는환자의경우수술후시점에서영양학적부작용이더해질수있다는점에서영양관리에신경을써야만한다. 비만대사수술자체만으로소화관의구조가바뀌고식사섭취량이제한됨으로써영양소의흡수가떨어지게되는데, 수술전이미영양소의결핍이있으면비만대사수술후에도교정되지않거나악화되어영양결핍의발생을높인다 [5-7]. 비만대사수술을앞둔고도비만환자에서결핍된일부미세영양소들에대해서는연구마다이견을보이기도하지만, 비타민 D와철은대표적인결핍영양소로서수술후심한결핍이지속되면골다공증과빈혈외에도심혈관계질환이나면역력에까지악영향을줄수있다 [8,9]. 그밖에도미세영양소결핍으로인한장해는아연결핍 투고일 : 2016 년 12 월 1 일, 심사일 : 2016 년 12 월 11 일, 게재확정일 : 2016 년 12 월 13 일책임저자 : 박성수, 서울시성북구인촌로 73 고려대학교안암병원외과우 : 02841 Tel: 02-920-6772, Fax: 02-928-1631, E-mail: kugspss@korea.ac.kr CC This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright 2016, The Korean Society for Metabolic and Bariatric Surgery
Vol. 5, No. 2, 2016 으로인한탈모부터베르니케뇌증 (Wernicke encephalopathy) 처럼건강을심각하게위협하는것까지매우다양하므로 [10,11], 이에대해비만대사수술전에미리검사하고필요한경우보충하는것이중요하다. 비만대사수술전관리의주요항목으로대두되던수술전체중감량에대해서는과잉체중의 5% 혹은 10% 의일정비율이상을감량한환자들이그렇지않은경우보다간비대와내장지방량을개선시켜수술시간과입원기간을단축시키는효과뿐아니라, 수술후 1년뒤에도체중을더많이감량했다는보고들이있다 [12-15]. 이를근거로들어일부국가에서는비만대사수술전에체중을감량하는것을보험조건으로내걸고있는데, 이에대해미국의대사비만학회 (The American Society of Metabolic and Bariatric surgery, ASMBS) 에서는그효과에대한객관적인증거가명확하지않다고지적하며, 특히수술전체중감량을보험급여의기준으로강제화하는것은위험할수있다고경고하고있다 [16,17]. 저자들은비만대사수술을앞둔체질량지수 (body mass index, BMI) 35 이상의고도비만환자를대상으로시행된선행연구들을검토하고, 결핍된미량영양소와이에대한비만대사수술전관리에대해고찰하여비만대사수술전체중감량의효과와영양학적관리에대한최신지견을설명하고자한다. 본론 1. 고도비만환자의미량영양소결핍 1) 수술전결핍비만환자는정상체중의사람에비해칼로리섭취가더높지만오히려비타민과미네랄등각종미량영양소의결핍에더욱취약하다 [2,3]. 고도비만환자에서쉽게결핍되는가장대표적인비타민은비타민 D로, 비만대사수술을앞두고있는 BMI 평균 56.4의고도비만환자들과정상체중의사람들을직접비교한연구에서비타민 D 결핍이고도비만환자에게서약세배 (Pvalue<0.0001) 높은발생률을보였으며부갑상선호르몬상승또한스무배이상 (P-value<0.0001) 의차이로동반되었다 [18]. 널리알려진골다공증관련질환외에도비타민 D가결핍되면비만의합병증인당뇨나심혈관계질환, 그리고암으로인한사망률까지도높인다는보고가있다 [8]. 비타민 D 결핍의이유로는비만한사람들이마른사람들보다햇빛을덜보는경향이있다는것과지방조직에비타민 D가격리됨으로써혈청농도가떨어진다는것이가장많이언급되어온기전이나 [19-21], 최근에는단순히부피가큰사람에서농도가희석되는효과라는주장이대두되며햇빛노출과는관련이없다는근거도제시되었다 [18,22,23]. 또한비타민 D는고도비만환자에서결핍된미량영양소중 BMI 와의상관관계에대해가장많이연구가이뤄져, 여러문헌에서 BMI와비타민 D가반비례한다고제시하였으며 [24-29] 몇몇연구에서는그렇지않다고보고하기도했다 [30,31]. 비타민 D가공복혈당과도반비례한다는연구결과도있었다 [25]. 철분은고도비만환자에서결핍되는대표적인미네랄로비만환자에게서늘어난혈장량, 고칼로리지만영양소는부족한음식섭취, 그리고지방축적과다로인한만성염증이철항상성과관련있는것으로알려졌다 [32,33]. 철분은가임기여성에서부족한것으로흔히알려졌으나철결핍성빈혈의경우남자이거나젊은고도비만환자에서흔하다는결과가있었는데, 이는간질환이나다른합병증의여부와관련있는것으로해석되었다 [34]. 최근한연구에서는고도비만환자가비만대사수술을받기전에철분수치가정상일경우수술후의철분결핍이더욱쉽게정상치로회복된다는연구결과를제시하며, 수술전에고도비만환자의철분결핍을체크하여미리보충할것을강조했다 [35]. 비타민 D와철분을포함해페리틴 (ferritin), 엽산 (folic acid), 아연 (zinc) 등의미네랄과비타민 D 외의다른비타민들에대해서도수술전고도비만환자들에게서나타나는결핍양상을살펴본연구들을검토한결과, 가장많이다뤄진총 13개의항목에대해정상범위를벗어나는환자비율을 Table 1에기술하였다 [36,37]. 2006년부터 2016년까지적게는 43명부터많게는 379 명까지의환자군을대상으로한 12개의선행연구가있었다. 각연구마다인종과남녀비율, 그리고영양소의결핍을판단하는기준등은조금씩달랐지만, 가장확연하게결핍된양상을보이는미량영양소는비타민 D(57-97%) 와철분 (9-44%) 이었다. 본분석에서는환자군의 5% 미만에서결핍을보이는경우유의미하지않은것으로정의하여서, 칼슘은포함된연구에서모두고도비만환자에게특별히결핍되지않은것으로평가하였다. 엽산, 페리틴, 헤모글로빈, 인 (phosphate), 그리고비타민 B 12 는일부에서는결핍되지않은것으로나타났으나다수의연구에서결핍된양상을보였고, 아연은다수에서결핍되지않은것으로보여졌다. 이중엽산 (<5-25%) 과인 (<5-22%), 아연 (<5-74%) 의경우연구마다격차가매우커일부연구에서는결핍되지않은양상을보였으나일부에서는높은결핍발생률을보였다. 알부민 (albumin) 의경우포함된 6개의연구중반수에서약간결핍된양상 (6-13%) 이었고반수에서는결핍되지않은것으로보여졌다. BMI에따른환자군을세부적으로나눈다른한연구를참조했을때 BMI 35 초과 50 이하까지는알부민이 8.5-8.9% 의낮은결핍발생률을보였으나 BMI 50 초과환자군에서만 28.6% 의결핍을보여 [24], 저자들이설정한 BMI 35 이상의고도비만기준이알부민결핍과의연관성을보이기에부적합할수있다고사료되었다. 54
홍주연, 박성수 : Table 1. Micronutrient deficiencies in morbidly obese patients before bariatric surgery according to the literature [6,7,24-26,30,31,34,36-39] Patients (n) % of deficiency High PTH Albumin Calcium Ferritin Folic acid Hemoglobin Iron Magnesium Phosphate Zinc Vitamin A Vitamin B12 Vitamin D (%) Flancbaum et al. (2006) 379 <5 <5 8.4-22 44 - - - - <5 68 - Toh et al. (2009) 232 <5 <5 - - 6.4 16 - <5 - - <5 57 25 Ernst et al. (2009) 232 13-6.9 <5 10 - <5 8.0 25-18 90 37 Schweiger et al. 114 - - 24 24 19 35 - - - - - - 39 (2010) Dammes-Machado et al. (2012) 54 - <5-6.0-29 - - - <5 9.0 83 - de Luis et al. (2013) 115 6.1-5.7 25 <5 - - - 74 <5 9.5 97 23 Nicoletti et al. 80 6.0 - <5 <5 10 9.0 19 - <5 15 <5 - - (2013) Lefebvre et al. 267 - <5 5.7-6.1 17 35 22 <5 17 8.4 68 - (2014) van Rutte et al. 200 <5 <5 7.0 24 5.0 38 <5 14 <5 <5 12 81 29 (2014) Wolf et al. (2015) 43 - <5 - - - - <5 <5 - - - 91 23 Ewang-Emukowhate 118 - - - 18-44 - - - - 25 92 - et al. (2015) Sánchez et al. 103 - <5 8.7 <5 7.7 13 - <5 <5-11 72 66 (2016) 55
Vol. 5, No. 2, 2016 2) 수술후발생가능한결핍고도비만환자가비만대사수술을받게되면수술전과비교해영양결핍이더욱악화된다. 위와십이지장이절제됨으로써내인성인자 (intrinsic factor) 와위산의도움을받아흡수되는비타민 B 12 와철분의흡수가불량해지고, 영양소의주요흡수장소인십이지장과소장일부를우회함으로써그외비타민과아연, 칼슘, 엽산등의영양소의흡수에지장이생기게된다 [40]. 비만대사수술전후의영양상태를비교했을때수술전보다후에서페리틴, 헤모글로빈, 철분, 아연, 비타민 B 12 의결핍이늘어났으며위소매절제술 (sleeve gastrectomy, SG) 보다 Roux-en-Y 위우회술 (Roux-en-Y gastric bypass, RYGB) 시행시더심하게결핍되어비타민 B 12 나페리틴의경우 SG보다 RYGB 시행후에결핍이 10% 이상늘어났다 [6,7,38,41]. 두수술군에서공통적으로수술후에결핍이심화되지않은영양소는비타민 D로, 장기간추적했을때결핍발생률이수술후낮아졌다가시간이지나면서다시상승하는추세를보였다 [41]. 이는비타민 D의충분한보충이이루어졌거나수술후비타민 D를격리하고있던지방조직이분해되기때문인것으로해석된다 [38]. 그밖에비만대사수술로인한영양결핍이일으킬수있는문제로는아연결핍으로인한탈모가있다. 수술후아연결핍, 특히아연과철분이함께결핍된경우탈모와강한상관관계를보였고, 비만대사수술 6개월후탈모가없던환자들은탈모가발생한환자들에비해아연과철분섭취가높았다는보고도있다 [10,42]. 또한비만대사수술후에구토를지속적으로하는환자에서탈수나저칼륨혈증, 저마그네슘혈증외에티아민 ( 비타민 B 1) 결핍을주의해야한다. 티아민결핍으로인해각기병 (beriberi) 과베르니케뇌증이일어날수있는것으로알려져있어검사를해보지않더라도지속적인구토만으로경험적티아민보충 (empiric thiamine treatment) 의적응증이된다 [11,40,43,44]. RYGB 시행이후에변비를보이는환자에서도티아민결핍을의심해볼수있으며티아민을보충해주었을때배변활동이원활해질수있다 [45]. 3) 수술전영양보충의필요성영양결핍문제를대처함에있어비만대사수술전에영양상태평가를통한예방적혹은치료적보충을하는것이점차중요하게여겨지고있다. 비만대사수술에대한영양과관련하여최초로제시된 ASMBS 2008년가이드라인에서는영양결핍에대한수술후검사및보충에대한내용이대부분이었으나 [46], 최근업데이트된 2016년가이드라인에서는티아민, 비타민 B 12, 비타민 D와칼슘, 엽산, 철분, 비타민 A, E, K 등의모든미량영양소에대해수술전검사를권고하는내용이새롭게추가되었다. 티아민의경우이전에는멀티비타민섭취정도로결핍이해결된다는주장도있었으나, 수술후에티아민결핍증상이수술전티아민 레벨이낮았던환자에게서더많이일어나는것으로보고되어수술전의검사및보충이필요한것으로권고되었다 [34]. 비타민 B 12 의검사에대해서는혈청 B 12 분석이비타민 B 12 결핍을 25-30% 가량놓치는것으로보고되어메틸말론산 (methylmalonic acid, MMA) 분석으로비타민 B 12 결핍의위험성을감지하는것이더욱정확한방법으로권고되었으며 [47], 보충에대해서는현재까지나온연구결과들이각기달라이상적인용량을명확히규정하기어렵다. 비타민 D의수술전정규검사는근거레벨 A등급으로강력히권고되고있다. 최근신진대사가건강하나비만한 (metabolically healthy but obese, MHO) 사람에게서인슐린저항성이낮고염증이덜일어나는것이비타민 D 때문일것이라는제안이나오면서비타민 D의방어측면의대사효과가대두된다 [48]. 수술후의보충으로는골교체 (bone turnover) 가상승하는것을예방하기어려우니수술전에비타민 D 결핍여부와함께골밀도검사를병행할것을권고하고있으며, 비타민 D 결핍이있을때비타민 D 2 보다는 D 3 로보충하는것이더효과적이라는근거가강하게제시되었다 [49]. 엽산은환자가적극적으로보충에대한순응도를보일경우결핍을충분히예방할수있으므로수술전이상적인수치에서조금이라도떨어져있는지세밀하게검사하고예방하는것이중요하다. 특히임신가능성이있는여성에서는매일 800-1,000 μg 복용하는것이권고되지만, 하루에 1 mg 이상보충하는것은비타민 B 12 의결핍을발견할수없기때문에권장되지않는다 [50]. 적혈구엽산 (erythrocyte folate) 과함께호모시스테인 (homocysteine) 이엽산의상태를반영하는데민감도가높은지표들로알려져있다 [51]. 철분또한수술전정규검사와함께빈혈, 무기력증등의동반증상이있는지확인해야하며, 혈청페리틴과트랜스페린포화도 (transferrin saturation) 를함께측정하는것이결과해석에도움이된다. 특히가임기여성의경우철분을예방적으로보충하는것이수술후나타날수있는철분결핍을효과적으로예방하는것으로보고되었으나, 철분보충이빈혈의예방과는연관성이없는것으로나타났다 [52]. 비타민 A, E, K의경우고도비만환자에서수술전에결핍되어있는경우는드물지만결핍위험을줄이기위해수술전후로모니터링하는것이권장되고, 아연과구리의수술전검사에대한근거는아직부족한상태이다. 2. 고도비만환자의수술전체중관리 1) 수술전체중감량의효과비만의동반질환으로익히알려진당뇨, 고혈압, 수면무호흡외에도고도비만환자들은전신마취와수술후합병증에취약한것으로알려져있다 [53]. 최근대두된 비만의역설 (obesity paradox) 에대한연구에의하면정상체중보다과체중이나 BMI 40 이하의비만환자에서오히려일반적인수술후에사망률이 56
홍주연, 박성수 : 감소한다고했으나 BMI가그이상인환자에서는사망률이되려높았고 [54], 또다른연구에서도높은 BMI 환자군이생존률이높았다는결과가있었으나높은 BMI의기준을 25로설정하는등고도비만환자에대한근거는찾을수없었다 [55]. 그리고비만환자에서수술후합병증이더많이발생하는것에대해서는두연구모두에서이견이없었다. 일반적으로고도비만환자가체중을감량하면혈압과고지혈증이개선되어심혈관계질환의위험도가낮아지고 [56], 만성염증상태가호전되어 C반응성단백질 (C-reactive protein, CRP) 과피브리노겐 (fibrinogen) 수치가떨어지며 [57], 안티트롬빈 (antithrombin) III 수치가정상으로돌아와혈전색전성위험을낮춘다고알려져있다 [58]. 따라서비만대사수술을앞둔고도비만환자가수술전체중감량을하는것이수술후합병증감소와수술효과에어떤영향을미칠지에대한연구들이진행되었다. 비만대사수술을받은고도비만환자의수술전체중감량 (preoperative weight loss, PWL) 을다룬선행연구중수술후체중감량에대해추적한내용이포함된연구위주로 2005년부터 2015년까지발표된 12개의참고문헌을검토하였다 (Table 2)[61,62,64,66]. 대부분의연구에서 PWL 군에서의목표를체중의 10% 혹은과잉체중의 10% 로잡았지만, 실제로체중감량이이루어진정도는연구마다상이하다. 수술전체중감량을한경우수술후의체중감량에유의미한효과를보인경우가반수에서보였는데, PWL 군이과잉체중의 10% 이상을감량한연구에서는수술후체중감량에도도움이되는것으로보고되었다. PWL의정도에따라여러군으로나눠분석한결과전체적으로는수술후체중감량에영향이없는것으로판단한연구에서도수술 6개월후체중의 10% 이상을감량한군에서만유의미하게체중감량을많이한것으로나타났다 [60]. 반면수술전체중감량이아무런효과가없다는연구들중에서는체중이증가해도상관없다는결과도있었고 [67], 오히려 36개월, 48개월의장기적인추적결과수술전체중을증가했던환자군이오히려수술후에체중감량상태를잘유지하고있다는결과도있다 [63]. 수술후합병증여부에대해서는한연구를제외하고모두수술전체중감량과연관이없다는결론이었고, 수술시간에대해서는대부분의연구에서 PWL 군이유의미하게짧았음을보고하였다. PWL 군에서오히려수술시간이길었다는연구결과가유일하게하나있었는데, 해당연구에서 PWL 군이체중감량후에도 BMI 가더높았기때문에수술당시비만정도가영향을끼친것으로사료되어결과해석에주의해야한다 [65]. 그외수술전체중감량과수술시간의관련성이없다는결과는위소매절제술환자를대상으로한연구가유일했다 [67]. 2) 수술전체중감량의의무화비만대사수술전일정비율이상의체중을감량하면수술후체 중감량에도움이되며복부지방이줄고간비대가호전됨으로써수술시간단축에기여한다는일부연구결과를근거로 [12-15,59, 61,68,69], 다수의보험회사에서수술전에의사의지도아래체중관리 (medically-supervised weight management, MWM) 할것을수술의전제조건으로걸기도했다 [16,70]. 하지만실제로수술전체중감량을강제한환자들이그렇지않은환자들보다결과가좋았는지에대한연구결과분석을해보면수술후체중감량에대한결과도차이가없었을뿐아니라, 수술전체중감량강제요건을맞추지못해수술을포기하는환자들이생겨남을알수있었다 [71-73]. 이에대해 ASMBS에서는 2011년성명서와 2016년업데이트를통해비만대사수술전체중감량을의무화할학술적이고객관적인근거는없으며수술전에일정체중을감량할것을보험급여의조건으로한시스템은있어서는안된다고강력히권고하고있다 [16,17]. 본연구에포함된결과들을분석해보아도위소매절제술전체중감량과연관된수술시간단축의한연구를제외하면수술전체중감량의명백한효과를보여준결과는없었다 (Table 2). 다시말해서수술전초과체중의 10% 이상을감량하는것은도움이될수있겠지만, 수술후체중감량의효과증진을위해반드시필요한것은아니기때문에이의달성을위해수술이미뤄지거나지장을주는상황은피해야함을숙지해야한다. 3) 초저칼로리다이어트 (Very-low-calorie diet, VLCD) 초저칼로리다이어트란필요한모든영양소를함유하면서하루 800 kcal 이하로섭취하게끔만들어진규정식을의미한다 [74]. 비만대사수술전에초저칼로리다이어트로식사를대체하는것은수술전체중감량에도움이되고간비대를줄이며수술후합병증을낮춘다고보고되었다 [15,75-77]. 간의부피와내장지방을최대한으로줄이기위해서이상적으로는수술전 6주간초저칼로리다이어트를유지하는것이권장되고, 그렇지못하더라도최소 2주는초저칼로리다이어트를섭취해야효과가있다 [78]. 초저칼로리다이어트를일반식이보다액상으로섭취하는것이내장지방과체중감량에더욱도움이된다는보고가있었으며 [79], Optifast와 Modifast 등의 VLCD 제품또한섭취하기편리하고부작용이거의없다고보고되었다 [76]. 3. 비만대사수술전식이장애관리및심리사회적지지비만대사수술을받는환자에서폭식장애 (binge eating disorder, BED) 가있거나조금씩자주먹는 (graze eating) 습관이있는경우건강과관련한삶의질이유의미하게떨어지고수술후체중감소도더욱적게일어나는것으로보고되었는데 [80], 비만대사수술대상자중 33% 가조금씩자주먹는습관을보였고이중 32% 가조절에장애를겪었으며폭식장애와도깊은관련이있었다 [81]. 이들에서더높은확률로우울감과불안증세가 57
Vol. 5, No. 2, 2016 Table 2. Effect of preoperative weight loss on postoperative weight loss, complication rate, and operative time according to literature [12-14,59-67] Patients (n) Procedure Amount of PWL Postoperative weight loss (% EWL) Complication rate Operative time (min) Follow-up (mo) PWL NPWL Effect PWL<NPWL PWL NPWL Alvarado et al. (2005) 90 LRYGB 7.25% TBW 12 74.4, all combined Yes No 36 min shorter - Yes No 220.2 257.6 Alami et al. (2007) 61 LRYGB 8.2% TBW 3 6 Ali et al. (2007) 351 LRYGB <5%, 5-10%, >10% TBW Still et al. (2007) 884 LRYGB/ RYGB Alger-Mayer et al. (2008) 150 RYGB 9.5% TBW (16.1% EBW) 12 24 44.1 53.9 74.6 69.7 33.1 50.9 76.0 79.0 >10% EBW 12 2.12 times more likely to achieve 70% EWL No* - - - Yes - - - 36 55.3 49.4 Yes - - - Carlin et al. (2008) 295 LRYGB Various 12 66.2 65 No - - - No No 104.9 119.7 Harnisch et al. (2008) 203 LRYGB >4.54 kg 12 36 Huerta et al. (2008) 40 RYGB 8.3% TBW 24 62* 57* No No 21.8 min shorter - Riess et al. (2008) 353 LRYGB >4.54 kg 12 66.0 74.0 No Yes 147 137 Solomon et al. (2009) 61 LRYGB >5% EBW 12 85.5 65.7 Yes No - - Giordano et al. (2014) 548 LRYGB >10% EBW 12 72.3 63.1 Yes No 77.0 104.4 24 Sherman et al. (2015) 141 LSG 2.8% TBW 12 74.2 73.4 No - 96.9 95.6 63.9 57.5 63.5 70.9 EWL = excess weight loss, PWL = preoperative weight loss, NPWL = no preoperative weight loss, LRYGB = laparoscopic Roux-en-Y gastric bypass, TBW = total body weight, EBW = excess body weight, LSG = laparoscopic sleeve gastrectomy. *Group of >10% TBW loss had significantly greater EWL than all other groups at 6 months postoperatively. **% TBW. 58
홍주연, 박성수 : 나타나는등정신과적으로도더불안정했고, 정신과적문제가있을수록수술효과가좋지않다는연구결과도있다 [82,83]. 또한과거성적학대를받은적있는환자군에서체중감량에더실패하는경향을보였는데 [84], 이는해당환자군에서정신과적문제및식이장애가더많이발생하기때문으로추정된다. 따라서비만대사수술을앞둔환자에게서비정상적인식이습관이나폭식장애, 야식증 (night eating syndrome) 등의식이장애여부와함께정신과적문제에대해파악하여야한다. 일반적인문진으로알수없는것들을심리측정 (psychometric testing) 을이용해서환자의성격적특성이나정신과적문제에대한포괄적인정보를얻음으로써수술의효과에영향을끼칠만한요인들을평가할수있다 [85]. 삶의방향성에대한문항들로이루어진설문지로평가하는 SOC (sense of coherence) 점수가높을수록비만대사수술후체중감량에성공할확률이높다는연구가있다 [84,86]. 삶에대한일관성이뚜렷한사람일수록높은 SOC 점수로반영되었고, 이는삶에서받는스트레스나주변환경변화로인해무너질확률이적다는것을의미한다. 지난다이어트에서성공한경험이있고확신에차있는사람일수록수술후체중감량에성공하는비율이높았고, 비만대사수술을받기로한동기의근원이다른사람의시선으로인한사회적고충 (social distress) 일때보다환자내면의본질적인동기일때수술후체중감량에성공하는확률이높은것으로보고된다 [84]. 한연구에서는가족이나친구로부터비만대사수술에대한긍정적인지지를받은환자군에서그렇지않은경우보다수술후성공적인결과를보이는것으로나타나 [87], 환자의심리적, 사회적인안정감이수술효과에유의미한영향을끼치는것으로보여진다. 결론 고도비만환자는높은칼로리섭취에반해미량영양소의결핍에취약하고, 비만대사수술자체가영양소결핍을일으키는원인이되므로이에대한세밀한검사와보충이필요하다. 본문에서언급한미량영양소대부분에대해수술전에미리검사하는것의중요성이최근더욱강조되고있다. 수술전과잉체중의 10% 이상을감량하는것이환자에게도움이되겠으나, 이것을강제요건으로하여비만대사수술급여가불가하거나수술시점이연기되는것은금기시되는추세이다. 수술전에체중관리를시도할경우초저칼로리다이어트를액상으로섭취하는것이안전하고효과적인방법으로권장된다. 또한비만대사수술을앞두고식이장애나정신과적질환의여부에대해검사하고교정하는것이환자의예후에도움이될것이다. REFERENCES 1. Lonsdale D. The role of thiamin in high calorie malnutrition. Austin J Nutri Food Sci 2015;3:1061. 2. Xanthakos SA. Nutritional deficiencies in obesity and after bariatric surgery. Pediatr Clin North Am 2009;56:1105-21. 3. Kant AK. Consumption of energy-dense, nutrient-poor foods by adult Americans: nutritional and health implications. The third national health and nutrition examination survey, 1988-1994. Am J Clin Nutr 2000;72:929-36. 4. Kant AK. Reported consumption of low-nutrient-density foods by American children and adolescents: nutritional and health correlates, NHANES III, 1988 to 1994. Arch Pediatr Adolesc Med 2003;157:789-96. 5. Poitou Bernert C, Ciangura C, Coupaye M, Czernichow S, Bouillot JL, Basdevant A. Nutritional deficiency after gastric bypass: diagnosis, prevention and treatment. Diabetes Metab 2007;33:13-24. 6. Damms-Machado A, Friedrich A, Kramer KM, et al. Pre- and postoperative nutritional deficiencies in obese patients undergoing laparoscopic sleeve gastrectomy. Obes Surg 2012;22:881-9. 7. Toh SY, Zarshenas N, Jorgensen J. Prevalence of nutrient deficiencies in bariatric patients. Nutrition 2009;25:1150-6. 8. Schöttker B, Haug U, Schomburg L, et al. Strong associations of 25-hydroxyvitamin D concentrations with all-cause, cardiovascular, cancer, and respiratory disease mortality in a large cohort study. Am J Clin Nutr 2013;97:782-93. 9. Oppenheimer SJ. Iron and its relation to immunity and infectious disease. J Nutr 2001;131(2S-2):616S-33S; discussion 633S-5S. 10. Rojas P, Gosch M, Basfi-fer K, et al. Alopecia in women with severe and morbid obesity who undergo bariatric surgery. Nutr Hosp 2011;26:856-62. 11. Raziel A. Thiamine deficiency after bariatric surgery may lead to Wernicke encephalopathy. Isr Med Assoc J 2012;14:692-4. 12. Still CD, Benotti P, Wood GC, et al. Outcomes of preoperative weight loss in high-risk patients undergoing gastric bypass surgery. Arch Surg 2007;142:994-8. 13. Solomon H, Liu GY, Alami R, Morton J, Curet MJ. Benefits to patients choosing preoperative weight loss in gastric bypass surgery: new results of a randomized trial. J Am Coll Surg 2009;208:241-5. 14. Alvarado R, Alami RS, Hsu G, et al. The impact of preoperative weight loss in patients undergoing laparoscopic Roux-en-Y gastric bypass. Obes Surg 2005;15:1282-6. 15. Fris RJ. Preoperative low energy diet diminishes liver size. Obes Surg 2004;14:1165-70. 16. Brethauer S. ASMBS Position Statement on Preoperative Supervised Weight Loss Requirements. Surg Obes Relat Dis 2011;7:257-60. 17. Kim JJ, Rogers AM, Ballem N, Schirmer B. ASMBS updated position statement on insurance mandated preoperative weight loss requirements. Surg Obes Relat Dis 2016;12:955-9. 18. Goldner WS, Stoner JA, Thompson J, et al. Prevalence of vitamin D insufficiency and deficiency in morbidly obese patients: a comparison with non-obese controls. Obes Surg 2008;18:145-50. 19. Looker AC. Do body fat and exercise modulate vitamin D status? Nutr Rev 2007;65:S124-6. 20. Wortsman J, Matsuoka LY, Chen TC, Lu Z, Holick MF. Decreased bioavailability of vitamin D in obesity. Am J Clin Nutr 2000; 59
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