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Korean J Clin Lab Sci. 2019;51(3):277-285 https://doi.org/10.15324/kjcls.2019.51.3.277 Korean Society for Clinical Laboratory Science ORIGINAL ARTICLE Relationship between Arterial Stiffness as Measured by the Cardio-Ankle Vascular Index with Body Mass Index in Healthy Elderly Subjects Kyung A Shin Department of Clinical Laboratory Science, Shinsung University, Dangjin, Korea 건강한노인에서심장 - 발목혈관지수로측정한동맥경직도와체질량지수간의상관관계 신경아 신성대학교임상병리과 ARTICLE INFO Received August 10, 2019 Revised August 27, 2019 Accepted September 3, 2019 Key words Arterial stiffness Body mass index Cardio-ankle vascular index ABSTRACT An inverse correlation between obesity and arterial stiffness has been reported, but there are no consistent results in elderly subjects. This study examined the relationship between the arterial stiffness measured by the CAVI (cardio-ankle vascular index) and BMI (body mass index) in healthy elderly people. This study included 629 healthy elderly people aged 65 and over who underwent health examinations at a general hospital in Gyeonggi from July 2018 to June 2019. Metabolic syndrome was diagnosed using the criteria of the Adult Treatment Panel (ATP) III of the US National Cholesterol Education Program (NCEP). Among the criteria of NCEP-ATP III, the waist circumference and obesity criteria were based on the WHO criteria. All subjects underwent a biochemical blood test and an assessment of the CAVI. In both men and women, the CAVI was lower in the obese group than in the normal weight group. Gender (P=0.047), age (P<0.001), BMI (P<0.001), and waist circumference (P=0.008) were factors affecting the CAVI. Gender, high blood pressure, and hyperglycemia were independent positive predictors of the CAVI levels, while obesity was a negative predictor. Therefore, the CAVI and BMI showed an inverse correlation. In conclusion, there was an inverse correlation between the CAVI and BMI in the elderly, and obesity was a negative predictor of the CAVI. Copyright 2019 The Korean Society for Clinical Laboratory Science. All rights reserved. 서론 동맥경화 (arteriosclerosis) 는팽창성, 순응성및탄성계수와같은혈관특성을포함하는일반적인용어이다 [1]. 동맥경화는심혈관질환의예후를결정하는지표로서, 증가된동맥경화는 * Corresponding author: Kyung A Shin Department of Clinical Laboratory Science, Shinsung University, 1 Daehak-ro, Jeongmi-myeon, Dangjin 31801, Korea E-mail: mobitz2@hanmail.net * ORCID: https://orcid.org/0000-0001-5266-5627 심혈관질환의이환율및사망률증가와관련이있다 [2, 3]. 그러므로심혈관질환을예방하기위해동맥경화정도를검사하여그위험을평가하는것은매우중요하다 [4]. 동맥경화를평가하는방법은다양한데, 맥파전도속도 (pulse wave velocity, PWV) 는혈관경직도정도를판정하는전통적인측정법이기는하나측정시환자의혈압에의존하는것으로알려져있다 [5, 6]. 따라서실제동맥경화를반영하는 PWV의타당성은논란의여지가있으며, 혈압강하제를복용하는경우동맥경직도 (arterial stiffness) 가영향을받으므로이를평가하는데부적합 pissn 1738-3544 eissn 2288-1662 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.

278 Kyung A Shin. Relationship between Cardio-Ankle Vascular Index with Body Mass Index 하다 [6]. 최근심장-발목혈관지수 (cardio-ankle vascular index, CAVI) 가동맥혈관경직도를평가하기위한비침습적방법으로제시되며, 동맥혈관고유의경직도 에기초하여측정한다 [7, 8]. CAVI 는혈압을교정하는 Bramwell-Hill 방정식에의해계산되므로 PWV보다동맥경화지표로서더정확하고재현성이좋은것으로보고된다 [9, 10]. CAVI 를통한동맥경직도측정은평활근수축상태와동맥벽의기계적성질을모두반영한다 [11]. CAVI 는심혈관계사건및심근경색발병도와관련이있으며, 심혈관계사건의독립적인예측인자로보고된다 [12, 13]. 또한 CAVI 는당뇨병, 고혈압, 이상지질혈증및흡연과같은심혈관계질환의위험요소와관련이있으며, 대사증후군위험요인의증가와양의상관관계를보인다 [14-18]. 체중증가는동맥경화위험을증가시키는데기여할가능성이높다. Nagayama 등 [1] 은체중감소후내장지방면적이감소함에따라 CAVI 가감소하였으며, CAVI 의감소는내장지방비율이높은환자에서체중감소후혈관경직도가개선되었다는것을암시하는지표라고하였다. 높은 CAVI 는비만과관련이있지만, 일부연구에서는체질량지수 (body mass index, BMI) 와 CAVI 간에역상관관계가있다고보고하였다 [6]. 실제로소아와청소년을대상으로비만과혈관경직도간에역상관관계가보고되고있으나, 고령자나노인에서는일관된결과를보이고있지않다 [6, 19]. 또한선행연구들은동맥경직도를혈압의존성이있는 PWV로측정하였으며, CAVI 로측정한동맥경직도와 BMI간의병태생리학적관계는명확하지않다. 이에이연구에서는건강한노인을대상으로 CAVI 로측정한동맥경직도와 BMI간의연관성및비만정도가 CAVI 에미치는영향을조사하여, 동맥경화위험의예방과관리를위한기초자료를제공하고자하였다. 대상및방법 1. 연구대상자이연구는 2018년 7월부터 2019년 6월까지경기도에위치한종합병원에서건강검진을시행한 65세이상건강한노인을대상으로실시되었다. 이기간동안건강검진을실시한 65세이상의대상자중심혈관질환자, 뇌졸중, 신장질환자, 간질환자, 통풍의과거력이있는피험자를제외한최종연구대상자는 629명이었다. 또한이횡단면연구는경기도에위치한종합병원에서기관생명윤리위원회 (institutional review board, IRB) 의승인후진행되었다 (IRB No: SP-2019-07-032-001). 2. 연구방법 1) 신체계측과혈압측정체성분분석기인바디 720 (Biospace Co., Seoul, Korea) 을통하여신장과체중을측정하였고, 체중을신장의제곱으로나누어 BMI를계산하였다. 비만분류는정상은 BMI가 18.5~22.9 kg/m 2, 과체중은 BMI 23~24.9 kg/m 2, BMI 25 kg/m 2 이상은비만으로정의하였다 [20]. 허리둘레측정은갈비뼈가장하단부와골반의가장높은부위의중간지점인가장폭이좁은부위를직립자세에서측정하였다. 혈압은안정된상태에서보정된아네로이드식혈압측정기 (Medisave UK Ltd., Weymouth, UK) 로상완위치에서측정하였다. 2) 대사증후군위험요인및진단기준대사증후군진단은 2001년발표된 US National Cholesterol Education Program (NCEP) 의 Adult Treatment Panel (ATP) III의기준에따라 5가지위험요인중 3가지이상해당되면대사증후군으로판정하였다 [21]. 구체적인대사증후군위험요인은 1 허리둘레 ; 남성 102 cm, 여성 88 cm 2 혈압 ; 수축기혈압 130 mmhg 또는이완기혈압 85 mmhg 3 공복혈당 110 mg/dl 4 HDL-콜레스테롤 ; 남성 <40 mg/dl, 여성 <50 mg/dl 5 중성지방 150 mg/dl이었다. NCEP-ATP III의대사증후군위험요인중허리둘레는 WHO의아시아태평양지역의기준에근거하여남성 90 cm, 여성 80 cm을적용하였다 [20]. 3) 혈액분석방법혈액검사는 8시간이상금식후아침에주전정맥 (antecubital vein) 을통해혈액을채취하여분석하였다. 총콜레스테롤 (total cholesterol, TC), 중성지방 (triglyceride, TG), 고밀도지단백콜레스테롤 (high density lipoprotein-cholesterol, HDL-C), 저밀도지단백콜레스테롤 (low density lipoprotein-cholesterol, LDL-C), 공복혈당 (fasting blood glucose, FBG), 요산 (serum uric acid, SUA), 고감도 C-반응성단백 (high sensitivity C-reactive protein, hs-crp) 의혈중농도측정은 TBA-200FR NEO (Toshiba, Tokyo, Japan) 로표준화된방법에따라측정하였다. 면역비탁법 (turbidimetric immunoassay, TIA) 의원리로고감도 C-반응성단백을정량분석하였다. 당화혈색소 (hemoglobin A1c, HbA1c) 는고속액체크로마토그래피법 (high performance liquid chromatography) 의원리로 Variant II (Bio Rad, CA, USA) 측정장비로검사하였다. 인슐린은전기화학발광면역분석

Korean J Clin Lab Sci. Vol. 51, No. 3, September 2019 279 법 (electrochemiluminescence immunoassay) 의원리로 Roche Modular Analytics E170 (Roche, Mannheim, Germany) 로측정하였다. 4) CAVI 측정 CAVI 는누운자세에서안정을취한후 VaSera VS-1000 (Fukuda Denshi, Tokyo, Japan) 을사용하여측정하였다. CAVI 는다음의방정식을통하여얻었다. CAVI, stiffness parameter =a [2 /(P s P d ) In(P s /P d ) PWV 2 ]+b (a, b; 상수, ; 혈액밀도, P s/p d; 수축기혈압 / 이완기혈압, PWV; 맥파전도속도 ) 의방정식이다 [9]. PWV는맥파가대동맥판에서발목까지전파되는시간으로혈관길이를나눈값으로, 상완과발목에서커프를사용하여측정하였다. 모든측정및계산은 VaSera VS-1000에의해자동으로수행되었다. 이와같은방법으로측정한 CAVI 의평균변동계수는 5% 미만이었다. 또한높은 CAVI 는 9 m/s 이상이면위험범위에해당되는것으로정의하였다 [22]. 이연구에서측정한좌측과우측의 CAVI 는통계적으로유의한차이를보이고있지않아 (8.47±1.24 vs 8.46±1.29) 우측의 CAVI 를연구에이용하였다. 3. 통계분석통계분석은 SPSS 통계프로그램 24.0 (SPSS Inc, Chicago, IL, USA) 패키지로통계분석하였으며, 모든데이터는평균 ± 표 준편차로나타냈다. 임상적특성의성별에따른차이, 대사증후군위험요인의존재유무에따른집단간차이를알아보기위해 Independent sample t-test를수행하였다. 대사증후군및대사증후군위험요인의성별에따른빈도차이를알아보기위해 Chi-squared test를실시하였다. 또한성별에따라정상체중군, 과체중군, 비만군의대사증후군위험요인및 CAVI 의차이를알아보기위해 One-way ANOVA 로분석하였으며, 집단간유의한차이가있는경우 Scheffe 방법으로사후검정을실시하였다. 성별에따른 CAVI 와대사증후군위험요인및 BMI간의상호연관성을알아보고자상관관계분석을실시하였다. CAVI 를종속변수로대사증후군위험요인및 BMI를독립변수로설정하여두변수사이의관계를규명하기위해다중회귀분석을시행하였다. 또한성별및각각의대사증후군위험요인의존재유무, 비만정도에따른 CAVI 의위험치발병을예측하기위해로지스틱회귀분석을실시하였으며, 교차비 (Odds ratio) 및신뢰구간 (confidence interval, CI) 을구하였다. 이연구에서 P값은 0.05 미만일경우통계적으로유의한것으로판단하였다. 결과 1. 임상적특성의성별에따른차이성별에따라신장, 체중, BMI, 허리둘레는집단간차이를보였다. 신장 (P<0.001), 체중 (P<0.001) 및허리둘레 (P=0.012) Table 1. Characteristics of male and female participants Variables All (N=629) Male (N=482) Female (N=147) P value Age (years) 71.32±5.16 71.46±5.27 70.88±4.76 0.238 Height (cm) 161.24±7.93 164.02±6.34 152.12±5.37 <0.001 Body weight (kg) 63.59±9.77 65.01±9.90 58.96±7.70 <0.001 BMI (kg/m 2 ) 24.45±3.18 24.13±3.19 25.50±2.92 <0.001 WC (cm) 84.47±8.20 84.92±8.38 82.98±7.41 0.012 sbp (mmhg) 119.90±15.21 119.32±14.57 121.80±17.07 0.112 dbp (mmhg) 74.80±9.21 74.53±8.85 75.68±10.29 0.224 TC (mg/dl) 187.20±33.96 183.64±32.63 198.88±35.67 <0.001 TG (mg/dl) 123.41±69.91 121.11±67.43 130.95±77.24 0.136 HDL-C (mg/dl) 53.71±13.74 53.42±13.77 54.69±13.63 0.327 LDL-C (mg/dl) 113.75±30.96 110.51±29.66 124.36±32.83 <0.001 FBG (mg/dl) 98.29±22.64 99.06±23.31 95.77±20.19 0.123 HbA1c (%) 6.04±0.89 6.06±0.94 6.03±0.78 0.714 Insulin (µu/ml) 6.16±5.14 6.11±5.95 6.20±4.46 0.944 SUA (mg/dl) 5.32±1.44 5.57±1.40 4.51±1.27 <0.001 hs-crp (mg/dl) 0.24±0.50 0.27±0.56 0.16±0.25 0.002 CAVI 8.47±1.24 8.58±1.28 8.11±1.00 <0.001 Values are presented as means±standard deviations. Calculated by independent t-test. Abbreviations: BMI, body mass index; WC, waist circumference; sbp, systolic blood pressure; dbp, diastolic blood pressure; TC, total cholesterol; TG, triglyceride; HDL-C, high density lipoprotein cholesterol; LDL-C, low density lipoprotein cholesterol; FBG, fasting blood glucose; HbA1c, hemoglobin A1c; SUA, serum uric acid; hs-crp, high sensitivity C-reactive protein; CAVI, cardio-ankle vascular index.

280 Kyung A Shin. Relationship between Cardio-Ankle Vascular Index with Body Mass Index 는남성에서크게나타났으나, BMI (P<0.001) 는여성이높게나타났다. 혈액변인중총콜레스테롤 (P<0.001), LDL-콜레스테롤 (P<0.001) 은여성이유의하게높았으나, 요산 (P<0.001), hs-crp (P=0.002), CAVI (P<0.001) 는남성이유의하게높은것으로나타났다. 그러나성별에따라연령, 수축기와이완기혈압, 중성지방, HDL-C, 공복혈당, HbA1c, 인슐린은통계적으로유의한차이가없었다 (Table 1). 또한성별에따라복부비만, HDL-C의감소, 대사증후군유병률은유의하게여성에서높은빈도를보였으나 ( 모두 P<0.05), 높은혈압, 고혈당및고중성지방혈증은성별에따른유의한빈도차이는보이지않았다 (Figure 1). 군이높게나타났으며, 비만군은과체중군보다높았다 ( 각각 P< 0.001). 중성지방은정상체중군보다과체중 / 비만군이높았으며 (P=0.001), HDL-C은정상체중군보다과체중 / 비만군이낮 2. 비만정도에따른대사증후군위험요인및 CAVI 의차이 남성은정상체중군보다비만군의연령이유의하게높았으며, BMI와허리둘레는정상체중군보다과체중 / 비만군이높았다 ( 각각 P<0.001). 총콜레스테롤 (P=0.029) 과 LDL-C (P=0.004) 은정상체중군보다과체중군이높았으며, 중성지방은정상체중군보다과체중 / 비만군이높았다 (P<0.001). 그러나 HDL-C은정상체중군보다과체중 / 비만군이낮게나타났다 (P<0.001). 여성의경우 BMI와허리둘레는정상체중군보다과체중 / 비만 Figure 1. Prevalence of MetS and MetS components in males and females. Prevalence of central obesity (25.5 vs 69.4), reduced HDL-C (14.7 vs 42.2) and metabolic syndrome (13.1 vs 30.6) was higher women than men. Abbreviations: See Table 1; MetS, metabolic syndrome. *P<0.05. Table 2. Comparison of risk factors of metabolic syndrome according to obesity degree Variables Normal weight Overweight Obesity P value Male (N) 133 129 220 Age (years) 72.72±5.65 71.58±5.47 70.62±4.76 a 0.001 BMI (kg/m 2 ) 20.28±1.65 23.47±0.50 a 26.86±1.95 ab <0.001 WC (cm) 76.18±6.17 84.40±4.12 a 90.51±6.60 ab <0.001 sbp (mmhg) 118.05±15.11 119.73±14.36 119.84±14.37 0.497 dbp (mmhg) 73.53±9.06 74.65±9.46 75.07±8.32 0.284 TC (mg/dl) 178.34±31.78 189.06±32.20 a 183.66±33.01 0.029 TG (mg/dl) 89.99±52.95 124.40±64.41 a 138.00±70.65 a <0.001 HDL-C (mg/dl) 58.51±14.65 52.16±13.19 a 51.07±0.86 a <0.001 LDL-C (mg/dl) 104.14±28.27 116.17±30.30 a 111.02±29.49 0.004 FBG (mg/dl) 96.27±27.28 97.91±19.98 101.41±22.39 0.108 Female (N) 21 34 92 Age (years) 71.25±5.83 71.21±4.15 70.73±4.77 0.835 BMI (kg/m 2 ) 21.35±0.87 23.59±0.50 a 27.20±2.19 ab <0.001 WC (cm) 74.05±6.06 79.68±3.72 a 86.34±6.24 ab <0.001 sbp (mmhg) 127.25±16.81 120.15±15.78 121.03±17.50 0.283 dbp (mmhg) 76.50±6.90 73.68±8.64 75.98±11.17 0.475 TC (mg/dl) 194.00±33.73 188.53±35.73 203.70±35.66 0.087 TG (mg/dl) 85.25±38.70 112.35±55.30 147.70±85.31 a 0.001 HDL-C (mg/dl) 61.05±14.51 56.00±13.30 52.70±13.24 a 0.036 LDL-C (mg/dl) 119.40±26.64 115.00±30.60 128.97±34.40 0.082 FBG (mg/dl) 97.70±16.71 91.94±21.98 96.82±20.31 0.443 Values are presented as means±standard deviations. Calculated by one way ANOVA and Scheffe test. Abbreviations: See Table 1. a Significantly different from normal weight at P<0.05, b Significantly different from overweight at P<0.05.

Korean J Clin Lab Sci. Vol. 51, No. 3, September 2019 281 았다 (P=0.036) (Table 2). CAVI 는남녀모두에서정상체중군보다비만군에서유의하게낮았다 ( 각각 P<0.05) (Figure 2). 또한복부비만, HDL-C의감소에대해서는위험요인이존재하는군보다위험요인이없는군에서높은 CAVI 치를보였다. 그러나높은혈압, 고혈당에대해서는위험요인이없는군보다위험요인이존재하는군에서높은 CAVI 치를나타냈다 ( 각각 P<0.05) (Figure 3). 또한대사증후군진단군은대사증후군비진단군보다 CAVI 치가높은경향을보였으나, 통계적으로유의하지는않았다. Figure 2. Comparison of cardio-ankle vascular index (CAVI) values according to degree of obesity. Abbreviations: See Table 1. a Significantly different from normal weight at P<0.05. 3. CAVI 에영향을미치는요인성별 (P=0.047), 연령 (P<0.001), BMI (P<0.001), 허리둘레 (P=0.009) 는 CAVI 로측정된동맥경직도에영향을미치는요인으로나타났다. 또한 CAVI 가커지면 BMI는작아지는역상관관계에있으며, BMI는 CAVI 로측정된동맥경직도에미치는영향력이다른지표들보다큰것으로나타났다 (Table 3). 4. CAVI 와대사증후군위험요인및 BMI과의연관성남성에서연령 (r=0.232, P<0.001), BMI (r= 0.101, P=0.026), 수축기혈압 (r=0.145, P=0.001), 공복혈당 (r=0.246, P<0.001) 은 CAVI 와상호유의한연관성을나타냈으며, 여성에서도연령 (r=0.288, P<0.001), BMI (r= 0.229, P=0.005), 수축기혈압 (r=0.194, P=0.018), 공복혈당 (r=0.185, P=0.025) 이 CAVI 와유의한연관성을보였다. 또한남녀모두에서 CAVI 는 BMI와유의한역상관관계를보였다 (Table 4). 또한 CAVI 9 m/s 이상과미만으로나누어대사증후군위험요인유무및비만정도에따른 CAVI 위험치발병률을확인한결과, 여성보다남성에서 CAVI 의위험치발병률을 2.14배높았으며, 높은혈압군은정상혈압군보다 CAVI 의위험치발병률이 1.48배높았다. 고혈당군은정상혈당군보다높은 CAVI 치를보일확률이 3.04배높았으며, 비만군은정상체중군보다높은 CAVI 치를보일확률이 0.37배낮은것으로나타났다. 따라서성별, 높은혈압, 고혈당, 비만은높은 CAVI 치의독립적인예측인자로나타났다 (Table 5). 고찰 이연구는건강한노인에서 CAVI 로측정한동맥경직도와 Table 3. Correlation of cardio-ankle vascular index (CAVI) with metabolic syndrome risk factors by multiple regression Variables SE P value Figure 3. Differences in cardio-ankle vascular index (CAVI) levels with and without metabolic syndrome risk factors. Abbreviations: See Table 1. *P<0.05. Gender 0.082 0.121 0.047 Age (years) 0.206 0.009 <0.001 BMI (kg/m 2 ) 0.263 0.024 <0.001 WC (cm) 0.164 0.009 0.009 sbp (mmhg) 0.112 0.005 0.047 dbp (mmhg) 0.004 0.007 0.944 TC (mg/dl) 0.197 0.009 0.444 TG (mg/dl) 0.100 0.001 0.158 HDL-C (mg/dl) 0.120 0.010 0.254 LDL-C (mg/dl) 0.182 0.010 0.450 GLU (mg/dl) 0.215 0.002 <0.001 R 2 =0.172, adjusted R 2 =0.157, P<0.001 Abbreviations: See Table 1; SE, standard error.

282 Kyung A Shin. Relationship between Cardio-Ankle Vascular Index with Body Mass Index BMI간의연관성을조사하였다. 그결과, 남녀모두에서 CAVI 치는정상체중군보다비만군에서낮았으며, CAVI 와 BMI는역상관관계를보였다. 또한성별, 높은혈압, 고혈당은 CAVI 치의독립적인정적예측인자이지만, 비만은부적예측인자였다. 과체중과비만은비정상적으로과도한지방축적을의미하며, 인슐린저항성, 이상지질혈증및고혈압과관련되어있어혈관재형성및심혈관계위험을증가시킨다 [6, 23, 24]. 비만에의한인슐린저항성은혈관경직 (vascular stiffening) 및당뇨병성혈관병증 (diabetic vasculopathy) 에대한독립적인예측인자로인식되며 [25], 동맥경화는수축기혈압및심실질량을증가시킬뿐만아니라이완기관상동맥관류 (coronary perfusion) 를감소시킨다 [26]. 최근심장-발목혈관지수 (cardio-ankle vascular index, CAVI) 라는새로운동맥경화진단지표가개발되어혈압에관계없이동맥경직도를정량화할수있게되었다 [7-10]. Ohashi 등 [27] 은 CAVI 의증가가 CT에의해측정된내장지방면적과더불어연령, 혈압, HbA1c과관련이있음을확인하였다. 또한 CAVI 는대사증후군및복부비만대상자에서높고, 체중감소에 의해감소하는것으로나타났다 [1]. 이와같이체중증가는동맥경직도의위험인자인반면, BMI와 CAVI 사이에역상관관계가보고된다 [6]. Park 등 [28] 은내장지방과심외막지방은 CAVI 와유의한상관관계를보이는반면, BMI는 CAVI 와음의상관관계가있다고보고했다. 본연구결과, 남녀노인에서 CAVI 치는정상체중군보다비만군에서낮았으며, 비만군은정상체중군보다높은 CAVI 치를보일확률이낮게나타났다. 따라서 BMI와 CAVI 로측정된동맥경직도는역상관관계를보였다. Nagayama 등 [6] 은건강한일본인을대상으로 CAVI 와 BMI 사이에역상관관계가있음을보여주었고, 이는대사장애가없는비만인에서동맥경직도의감소가나타날수있음을시사하는결과라고하였다. 더욱이성별로는남성, 고혈압및내당능장애는동맥경직도의독립적인정적예측인자로밝혀졌지만, 비만은부적예측인자로확인되었다. 일본인을대상으로한또다른연구에서도성별, 연령, BMI 및수축기혈압은 CAVI 와관련된주요독립변수로보고된다 [29]. Prenner 등 [30] 은고령의남성당뇨환자를대상으로 CAVI 는 BMI와유의한역상관관계 Table 4. Correlation coefficient of cardio-ankle vascular index with metabolic syndrome risk factors Variables Male Female r P value r P value Age (years) 0.232 <0.001 0.288 <0.001 BMI (kg/m 2 ) 0.101 0.026 0.229 0.005 WC (cm) 0.004 0.935 0.081 0.328 sbp (mmhg) 0.145 0.001 0.194 0.018 dbp (mmhg) 0.076 0.096 0.055 0.505 TC (mg/dl) 0.062 0.174 0.112 0.177 TG (mg/dl) 0.026 0.564 0.091 0.273 HDL-C (mg/dl) 0.055 0.230 0.127 0.124 LDL-C (mg/dl) 0.031 0.492 0.086 0.301 GLU (mg/dl) 0.246 <0.001 0.185 0.025 Abbreviations: See Table 1. Table 5. Odds ratio (95% CI) for high cardio-ankle vascular index (CAVI) Odds ratio 95% CI P value Gender (male; 1, female; 0) 2.135 1.367 3.334 0.001 Central obesity 1.155 0.745 1.789 0.520 Elevated BP 1.482 1.035 2.120 0.032 Reduced HDL-C 0.789 0.508 1.224 0.290 Elevated GLU 3.036 1.913 4.817 <0.001 Elevated TG 1.310 0.889 1.930 0.173 Normal weight (reference) Overweight 0.688 0.427 1.109 0.125 Obesity 0.371 0.228 0.604 <0.001 Abbreviations: See Table 1; CI, confidence interval; BP, blood pressure.

Korean J Clin Lab Sci. Vol. 51, No. 3, September 2019 283 를보였으며, 당뇨병단계가진행됨에따라 BMI가감소하고이는동맥경화와관련된다고보고하였다. 노인을대상으로한본연구에서도남성, 높은혈압, 고혈당은 CAVI 치의독립적인정적예측인자이지만, 비만은부적예측인자로나타나선행연구결과와유사하였다 [6, 29]. 또한성별, 연령, BMI, 허리둘레는 CAVI 에영향을미치는요인으로나타났다. BMI가동맥경화에미치는영향에대한기전은아직완전히이해되지않고있다. 그러나체중증가가심혈관질환발병위험을증가시킴에도불구하고심부전, 고혈압및만성신장질환이있는비만환자가정상체중환자보다사망률이낮고예후도좋다고보고되기도한다 [31-34]. 또한비만인의 10 25% 는인슐린감수성으로인해대사적으로건강한비만에속한다고보고된다 [35]. 그러나본연구에서는대사장애가없는비만인에대한분류가이루어지지않아지방조직의축적과동맥의병리생리학적관계를확인하기위해전향적인연구를통한설명이필요하다. 심혈관위험요인이없는건강한피험자에서 CAVI 는 20세 79세까지선형적으로증가한다고알려져있다 [7]. 또한공복혈당장애는당뇨병환자에서 CAVI 증가의독립적인위험인자이며, 인슐린요법으로혈당치를낮추면상대적으로짧은시간에 CAVI 가감소하는것으로나타났다 [7, 9, 36]. 본연구에서도고혈당군은정상혈당군보다높은 CAVI 치를보일확률이 3.04배높았으며, 이는고혈당이동맥경화와유의한관련이있는중요한요인중하나임을나타내는결과이다. 남성에서흡연은 CAVI 와 BMI의관계를분석하는데있어서중요한역할을할것을추론된다. 그러나이연구에서는정확한정보를수집하는데어려움이있어분석에포함하지못하였으며, 흡연을포함한다양한개인정보를반영한추가연구가필요하다. 또한 BMI와 CAVI 사이의연관성을확인하였지만, BMI와 CAVI 간의병리생리학적관계는조사할수없었다. 결론적으로, 이연구는노인을대상으로 CAVI 와 BMI간에역상관관계를나타내며, BMI로측정한비만은 CAVI 의부적예측인자임을확인하였다. 요약비만과혈관경직도간에역상관관계가보고되고있으나, 고령자나노인에서는일관된결과를보이고있지않다. 이연구에서는건강한노인을대상으로 CAVI 로측정한동맥경직도와 BMI간의연관성을조사하였다. 이연구는 2018년 7월부터 2019년 6월까지경기지역종합병원에서건강검진을시행한 65세이상건강한노인을 629명을대상으로하였다. 대사증후군진단은 US National Cholesterol Education Program (NCEP) 의 Adult Treatment Panel (ATP) III의기준에따랐으며, NCEP-ATP III의기준중허리둘레및비만기준은 WHO의기준에따랐다. 모든연구대상자는생화학적혈액검사및 CAVI 를측정하였다. 남녀모두에서 CAVI 치는정상체중군보다비만군에서낮았으며, 성별 (P=0.047), 연령 (P<0.001), BMI (P< 0.001), 허리둘레 (P=0.009) 는 CAVI 에영향을미치는요인이었다. 또한성별, 높은혈압, 고혈당은 CAVI 치의독립적인정적예측인자이지만, 비만은부적예측인자로나타나 CAVI 와 BMI는역상관관계를보였다. 결론적으로, 이연구는노인을대상으로 CAVI 와 BMI간에역상관관계를나타내며, BMI로측정한비만은 CAVI 의부적예측인자였다. Acknowledgements: None Conflict of interest: None Author s information (Position): Shin KA, Professor. REFERENCES 1. Nagayama D, Endo K, Ohira M, Yamaguchi T, Ban N, Kawana H, et al. Effects of body weight reduction on cardio-ankle vascular index (CAVI). Obes Res Clin Pract. 2013;7:E139-145. https://doi.org/10.1016/j.orcp.2011.08.154. 2. Vlachopoulos C, Aznaouridis K, O'Rourke MF, Safar ME, Baou K, Stefanadis C. Prediction of cardiovascular events and all-cause mortality with central haemodynamics: a systematic review and meta-analysis. Eur Heart J. 2010;31:1865-1871. https://doi.org/10.1093/eurheartj/ehq024. 3. Mitchell GF, Hwang SJ, Vasan RS, Larson MG, Pencina MJ, Hamburg NM, et al. Arterial stiffness and cardiovascular events: the Framingham Heart Study. Circulation. 2010;121:505-511. https://doi.org/10.1161/circulationaha.109.886655. 4. Tanaka H, Munakata M, Kawano Y, Ohishi M, Shoji T, Sugawara J, et al. Comparison between carotid-femoral and brachial-ankle pulse wave velocity as measures of arterial stiffness. J Hypertens. 2009;27:2022-2027. https://doi.org/10. 1097/hjh.0b013e32832e94e7. 5. Sugawara J, Hayashi K, Yokoi T, Cortez-Cooper MY, DeVan AE, Anton MA, et al. Brachial-ankle pulse wave velocity: an index of central arterial stiffness? J Hum Hypertens. 2005;19:401-406. https://doi.org/10.1038/sj.jhh.1001838. 6. Nagayama D, Imamura H, Sato Y, Yamaguchi T, Ban N, Kawana H, et al. Inverse relationship of cardioankle vascular index with BMI in healthy Japanese subjects: a cross-sectional study. Vasc Health Risk Manag. 2016;13:1-9. https://doi.org/10.2147/vhrm. s119646. 7. Shirai K, Hiruta N, Song M, Kurosu T, Suzuki J, Tomaru T, et al.

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