대한구강내과학회지 Vol. 32, No. 4, 27 한국인여성에서노화에따른초역치미각강도의변화 경북대학교치과대학구강내과학교실 노화가미각기능에미치는영향에관해서는아직도많은논란이계속되고있다. 노인에게서보이는미각기능의감퇴를정상적인노화현상으로보는시각과약물사용이나타액분비의감소에의한결과로보는시각이교차하고있으며, 또한미각기능을평가하는방법에따라서로다른주장이제기되기도하였다. 저자들은노화가초역치미각강도에미치는영향을구명하기위해서본연구를시행하였으며, 약물사용에의한영향을배제하기위해서장기적인약물사용의병력이없는 2 대의여성 3 명과 4-5 대의여성 31 명을피검자로선택하여염화나트륨, 설탕, 구연산, 염산키니네수용액에대한초역치미각강도를소리자극을이용한규모짝짓기방법으로측정한다음그결과를서로비교하였으며, 4-5 대여성에대해서는또한폐경의여부와타액분비량의다과에따른차이를비교하여다음과같은결론을얻었다. 1. 한국인 4-5 대여성은 2 대여성에비해저농도의염화나트륨수용액과저농도의설탕수용액에대한초역치미각강도가감소되었으며, 고농도의염화나트륨수용액과고농도의설탕수용액, 그리고모든농도의구연산수용액과염산키니네수용액에서는차이가없었다. 2. 한국인 4-5 대여성에서폐경으로인한초역치미각강도의변화는나타나지않았다. 3. 한국인 4-5 대여성에서타액분비량의다과에따른초역치미각강도의변화가염화나트륨수용액, 설탕수용액, 염산키니네수용액에대해서는나타나지않았다. 4. 한국인 4-5 대여성에서타액분비량이적은군이많은군에비해저농도의구연산수용액에대한초역치미각강도가높게나타났다. 주제어 : 노화, 초역치미각강도, 한국인여성, 타액분비량, 폐경 1)I. 서 인간은주변의환경으로부터오는다양한자극을수용함으로서환경에적응하고위험으로부터회피하여생존과자기보호의기능을수행할수가있다. 즉, 촉각이나청각을통해서물리적자극을느낄수있고, 시각을통해서빛자극을느낄수있으며미각과후각을통해서화학적자극을느낄수있다. 따라서만약 론 교신저자 : 최재갑 7-412 대구광역시중구삼덕 2 가 188-1 경북대학교치과대학구강내과학교실전화번호 : 53-42-595 팩스번호 : 53-426-2195 E-mail: jhchoi@knu.ac.kr 원고접수일 : 27-9-28 심사완료일 : 27-12-6 이러한여러가지감각기능의장애가초래된다면인간의환경에대한적응력의감소와위기대처능력의감소로인하여건강한삶을영위하기가어려울뿐아니라때로는생존자체가위협을받게된다. 미각과후각은음식물의섭취를도와서신체적건강을유지할수있게해주고, 먹는즐거움을느끼게함으로서정신적건강의유지에도큰기여를하기때문에인간의삶과생존에지대한영향을주는매우중요한감각기능이다. 1) 그뿐만아니라미각과후각은타액, 위액, 췌장액의분비를증가시키고췌장폴리펩타이드, 가스트린, 인슐린, 글루카곤의수치를높임으로써영양분의이용을위한대사기전에영향을주는것으로알려져있다. 2) 따라서화학감각의상실은음식물의선택과섭취에변화를가져올수있고, 영양분의이용에관여하는중요한기전을변화시킬수있기때문에영양상태와면역기능의장애가초래되고그로인 383
해질병의악화및체중감소도나타날수있다. 3-6) 대부분의사람들은연령의증가와함께시각과청각의감퇴, 자세유지능력과운동능력의감소, 언어기능의감소와같은여러가지신경학적장애를경험하게된다. 7) 미각과후각과같은화학감각도 2 대 -3 대의연령에서정점에이르고나서그후에는감퇴하는것으로알려져있지만, 8) 미각과후각은다른감각과는달리반응을일으키는자극의종류가다양하고주관적느낌을정량화하는데어려움이있기때문에노화로인해서나타나는변화를평가하는것이용이하지가않다. 특히미각의경우에는후각에비해증령에따른변화가적게나타난다는것이일반적인의견이며나이가들어도미각기능은대체적으로건전하게유지되는것으로알려져있다. 9-11) 따라서노인에게서미각감퇴가실제로나타나는것인지, 나타난다면단맛, 짠맛, 신맛, 쓴맛과같은네가지기본미각이모두영향을받는지아니면일부의미각만영향을받는지분명하지가않다. 특히미각기능의증령적변화는미각역치의측정과초역치미각강도의측정에서서로일치하지않는결과를보이기때문에혼란이가중되는요인이되고있다. 즉, 증령에따른미각역치의변화를측정한대부분의연구에서연령이증가할수록미각역치가증가하는것으로나타났기때문에노인의미각민감도가젊은이에비해감소하는것으로이해되고있다 11-15). 그러나초역치미각강도를측정하는경우에는미각역치의측정때와는매우다른결과를보이고있다. Bartoshuk 등 16) 은노인에게서대부분의기본미각에대한미각역치는증가하지만미각강도는나이가들어도감소하지않는다고한반면에, Weiffenbach 등 17) 과 Murphy 등 18) 은단맛과짠맛에대한미각강도는노화로인한변화를보이지않지만신맛과쓴맛에대한미각강도는감소한다고하였다. 그러나 Schiffman 등 19) 은노인에게서단맛 ( 인공감미료 ) 에대한미각강도도감소한다는것을보고한바가있으며, Mojet 등 2) 은모든미각에대한초역치강도가감소한다고하였기때문에이들의연구결과를더욱혼란스럽게만들고있다. 이와같이증령에따른초역치미각강도의변화에관한연구결과가보고자들마다서로일치하지않는이유는아마도미각기능의복잡성, 미각강도측정의어려움, 피검자의유전적및정신신체적다양성, 피검자들간의인종적및사회문화적차이등에기인할것으로추정되지만이에대한자료가부족하기때문에증령에따른초역치미각강도의변화를이해하기위해 서는보다많은연구가필요하다고하겠다. 특히한국인은오래전부터한반도라는특정한지역에서정착생활을하면서민족의이동이거의없었고타인종과의혈통교류도적었기때문에다른민족에비해비교적단일한인종적특성을유지하고있다고볼수있다. 또한언어와생활양식에있어서도독자적인문화권을형성하면서생활하였으며, 식생활습관도여타의민족과는뚜렷이구별되는특징을가지고있다. 따라서한국인의이러한인종적, 문화적특이성은인체의건강과질병에관한의학적인연구에서도중요한변수로고려되어야할것으로생각된다. 그럼에도불구하고한국인에게있어서노화와관련된미각기능의변화에관한연구는많지가않다. 박등 21) 은전기미각역치측정법으로증령에따른미각기능의변화를조사한바가있는데, 혀끝, 혀의측방, 엽상유두근처, 연구개부위에서전기미각역치가유의하게증가하였다고보고하였다. 그러나한국인을대상으로증령에따른화학적자극에대한초역치미각강도의변화를측정한연구는거의찾아볼수가없었다. 미각기능의평가에는주로다음과같은세가지방법이사용되고있다. 즉어떤미각물질이증류수와구별될수있는최저농도를측정하는 감지역치 (detection threshold) 검사 와어떤미각물질이나타내는맛을느낄수있는최저농도를측정하는 인지역치 (recognition threshold) 검사, 그리고어떤미각물질이인지역치이상의초역치농도에서나타내는맛의강도를측정하는 초역치미각강도 (suprathreshold taste intensity) 검사 등이다. 인지역치는감지역치보다항상높게나오지만대부분의경우에있어서이들역치값과초역치미각강도사이의상관관계는불량한것으로알려져있다. 22) 즉, 역치값이비슷한두집단이초역치미각강도에서큰차이를보이거나그반대로역치값은차이가나지만초역치미각강도는비슷한수준을보이는경우가있기때문에역치값으로초역치미각강도를추정할수는없다고하였다. 23,24) 그런데식사때느끼는미각은매우희석된역치농도수준의자극에의한것이라기보다는초역치농도수준의자극에의한것이기때문에환자들이호소하는미각상실은초역치미각강도의변화와더욱밀접한임상적관련성을가진다. 22,25) 따라서환자들이호소하는임상적인미각상실을보다실제적으로평가하기위해서는미각역치의측정보다는초역치미각강도를측정하는것이더타당하다고할수있다. 25) 한편 Bergdahl 과 Bergdahl 26) 은미각장애를호소하 384
한국인여성에서노화에따른초역치미각강도의변화 는환자의인구학적분포를조사한바가있는데, 남성보다는여성에서, 특히 4 대이상의여성에서유병율이급격히높아진다고하였다. 따라서이계층의여성에서증령으로인한미각기능의변화가나타나는지의여부를판정하는것이임상의학적측면에서매우중요한일이라고볼수있다. 이번연구는약물복용을하지않고전신적으로도건강한한국인 2 대젊은여성과 4-5 대여성을대상으로 4 가지기본미각에대한초역치미각강도를측정하여증령이미각기능에미치는영향을조사하기위해서시행되었다. 그와더불어폐경과타액분비량이초역치미각강도에미치는영향을평가하였다. 1. 실험군 Ⅱ. 재료및방법 경북대학교병원에근무하는 4 세이상의여자직원들중에이번실험의목적과취지를이해하고실험방법에관한설명을들은후이번실험에자발적으로참여하기로결정하고다음과같은선정조건을만족한 31 명을실험군으로하였다 : (1) 최근 6 개월이상어떠한약물도복용한경험이없어야한다. (2) 현재앓고있는전신적인질병이없어야한다. (3) 가철성의치를사용하지않아야한다. (4) 구강궤양과같은구강질병이없어야한다. 이들의평균연령은 5.8±5.1 세 (41 6 세 ) 이었다. 2. 대조군 경북대학교치과대학에재학중이거나경북대학교병원에서임상실습을하고있는 2 대의여학생들중에서전자의선정조건을만족하는 3 명을대조군으로하였으며, 이들의평균연령은 25.1±1.7 세 (21 29 세 ) 이었다. 3. 폐경여부의확인 피검자에대한설문조사로서폐경여부를확인하였다. 4. 타액분비율의측정 Saxon 방법으로타액분비율을측정하였다. 먼저피 검자로하여금약 5 cm 5 cm 크기의마른가아제를 2 분동안씹게한후 2 분동안늘어난가아제의무게를재어타액분비율을측정하였다. 2 분동안무게의증가량이 4 g 미만인경우에는저분비자, 4 g 이상인경우에는고분비자로구분하였다. 5. 미각검사용액의준비 4 가지기본맛에대한초역치수준에서의미각강도를측정하기위해서염화나트륨 (NaCl, MW=58.44), 설탕 (sucrose, MW=342.3), 구연산 (citric acid; MW= 21.14), 염산키니네 (quinine HCl; MW=396.91) 등을 1/2 log 단위로희석한수용액을사용하였다 (Table 1). 6. 규모짝짓기법 (magnitude matching) 을 이용한 초역치미각강도의측정 초역치미각강도의측정에있어서개인간의감각인지수준과표현의차이를보정하기위해서두가지감각을동시에측정하는규모짝짓기법을사용하였다. 이번연구에서는김등 27) 의연구에서사용한것과동일한방법의규모짝짓기법을사용하였는데, 한측정시기동안에미각기능과청각기능을동시에평가하였다. 청각자극은 Audiometer(AM232 Manual Audiometer, Welch Allyn, Inc., New York, U.S.A.) 에서발생하는 1, Hz 의 삐 소리를이용하였다. 소리는헤드폰을통해서들리게하였으며, 소리의강도는 25 db 부터 1 db 까지모두 6 가지단계로하였다. 미각자극의전달을위해서 5ml 의미각검사용액을입에넣고잠시머금어입전체를고루적신다음뱉어내게하였다. 매검사사이에증류수로입을헹궈내게하였다. 피검자에게 21 가지종류의미각자극과 6 가지종류 Table 1. Taste Stimuli (Molar Concentrations) NaCl Sucrose Citric Acid Quinine HCl Tone.1.1.32.32 25 db.32.32.1.1 4 db.1.1.32.32 55 db.32.32.1.1 7 db 1. 1..32.32 85 db.1 1 db 385
의청각자극을컴퓨터가정한순서에따라전달한후동일한 9점척도를이용하여피검자가느끼는강도를표시하게하였다. 이때피검자는 1-9 중에어떠한숫자도선택할수있으나숫자를비율로인식하게하였다. 이러한과정을 2회반복하여얻은점수를평균하여각각의미각용액과 삐 소리에대한감지강도를나타내는점수로하였다. 소리감지강도를기준으로미각감지강도를표준화하는과정은다음과같다. 먼저상위 5단계의 삐 소리에대한감지강도점수의기하평균을구하고, 그값으로 2을나누어서변환계수를구하고, 이변환계수를각각의미각감지강도점수에곱하면표준화점수 (normalized score) 가된다. 이표준화점수를해당용액에대한미각감지강도점수 (perceived intensity score) 로간주하였으며동일한미각의서로다른농도에서얻은표준화점수를모두합하여총점 (total intensity score) 을구하였다. 7. 자료의분석및통계처리 실험군과대조군에대해서각미각용액의농도별초역치미각강도의표준화점수및총점을비교하였으며, 또한실험군에있어서는폐경여성과폐경전여성, 타액의고분비자와저분비자사이에도비교하였다. 이상의비교에대한통계학적유의성은 Wilcoxon's rank sum test 로검정하였다. 타액의고분비자와저분비자사이에폐경자의비율은 Χ 2 -test 를이용하여비교하였다. Ⅲ. 결과 1. 2 대여성과 4-5 대여성사이에초역치미각강도의비교 2 대여성에비해 4-5 대여성은저농도의염화나트륨과저농도의설탕에대한초역치미각강도의감소를보였지만고농도의염화나트륨과고농도의설탕, 그리고모든농도의구연산과염산키니네에대한초역치미각강도의차이는보이지않았다. (Table 2-5, Fig. 1-4). Perceived intensity 45 4 35 3 25 2 15 1 5-2 -1.5-1 -.5 log concentration of NaCl solution (M) Fig. 1. Perceived taste intensity for NaCl in elderly and young women Table 2. Comparison of the normalized perceived taste intensity score for NaCl between elderly and young women NaCl Concentration (M) women * women 1. x 1-2 2.29 3.5 4.4 3.78.4.32 x 1-1 1.49 5.46 13.97 5.98.13 1. x 1-1 12.82 5.75 15.99 5.43.26.32 x 1 33.48 12.3 34.74 6.72.379 1. x 1 42.72 12.2 42.2 9.78.762 Total score 11.8 26.82 11.76 22.61.155 * : 5th-6th decades : 3rd decade 386
한국인여성에서노화에따른초역치미각강도의변화 Table 3. Comparison of the normalized perceived taste intensity score for sucrose between elderly and young women Sucrose Concentration (M) women * women 1. x 1-2 3.29 2.62 4.16 3.26.441.32 x 1-1 5.51 4.13 7.96 4.26.7 1. x 1-1 16.1 6.71 2.45 7.67.13.32 x 1 29.6 8.3 29.11 7.23.994 1. x 1 37.37 9.3 39.3 8.44.419 Total score 91.86 22.75 1.71 24.92.116 * : 5th-6th decades : 3rd decade Perceived intensity 45 4 35 3 25 2 15 1 5-2 -1.5-1 -.5 Perceived intensity 45 4 35 3 25 2 15 1 5-3.5-3 -2.5-2 -1.5 log concentration of sucrose solution (M) log concentration of citric acid solution (M) Fig. 2. Perceived taste intensity for sucrose in elderly and young women Fig. 3. Perceived taste intensity for citric acid in elderly and young women Table 4. Comparison of the normalized perceived taste intensity score for citric acid between elderly and young women Citric Acid Concentration (M) women * women.32 x 1-3 8.71 5.21 9.18 4.74.914 1. x 1-3 12.56 5.61 12.5 5.14.436.32 x 1-2 22.59 8.17 24.29 6.9.29 1. x 1-2 33.2 1.68 32.4 7.25.988.32 x 1-1 39.98 12.56 4.4 1.57.74 Total score 117.3 33.1 118.32 26.68.784 * : 5th-6th decades : 3rd decade 387
Table 5. Comparison of the normalized perceived taste intensity score for quinine HCl between elderly and young women Quinine HCl Concentration (M) women * women.32 x 1-5 3.75 3.14 5.94 5..178 1. x 1-5 4.71 5.12 4.66 3.77.629.32 x 1-4 11.26 9.24 13.13 1.1.484 1. x 1-4 21.76 9.38 23.21 1.42.436.32 x 1-3 34.96 11.21 33.12 12.28.64 1. x 1-3 4.58 11.15 37.71 1.87.379 Total score 117.3 35.8 117.7 43.8.92 * : 5th-6th decades : 3rd decade Perceived intensity 45 4 35 3 25 2 15 1 5-5.5-5 -4.5-4 -3.5-3 log concentration of quinine HCl solution (M) 46.6±3.3 세 ) 이었다. 평균타액분비량은폐경여성과폐경전여성에서각각 3.77±1.37 g, 4.45±1.33 g 이었다 (Table 6). 이들사이에초역치미각강도를비교해본결과염화나트륨, 설탕, 구연산, 염산키니네의모든농도에대해서유의한차이를보이지않았다. (Table 7-1) 3. 4-5 대여성군에서타액저분비자와고분비자사이에초역치미각강도의비교 Fig. 4. Perceived taste intensity for quinine HCl in elderly and young women 2. 4-5 대여성군에서폐경여성과폐경전여성사이에초역치미각강도의비교 4-5 대여성군에서폐경여성은 15 명 ( 평균연령 ; 54.9±2.8 세 ) 이었으며, 폐경전여성은 16 명 ( 평균연령 ; 4-5 대여성군에서 2 분간타액분비량이 4 g 이하인타액저분비자는 17 명이었으며평균분비량은 3.2±.8 g 이었다. 4 g 이상의타액고분비자는 14 명이었으며평균분비량은 5.3±.9 g 이었다 (Table 11). 저분비자와고분비자사이에초역치미각강도를비교해본결과저농도의구연산에대한미각강도가타액저분비자에서높게나타났으나그밖의모든용액과모든농도에서초역치미각강도의차이를보이지않았다 (Table 12-15). Table 6. Comparison of age and salivary flow rate between menopause and pre-menopause women in the 5th-6th decades Menopause Pre-menopause P-value Age 54.9±2.8years 46.6±3.3years <.1 Salivary flow rate 3.77±1.37g/2min 4.45±1.33g/2min.173 388
한국인여성에서노화에따른초역치미각강도의변화 Table 7. Comparison of the normalized perceived taste intensity score for NaCl between menopause women and pre-menopause women in the 5th-6th decades NaCl Concentration (M) Menopause Pre-menopause 1. x 1-2 2.6 2.62 1.98 3.36.287.32 x 1-1 9.51 4.62 11.15 6.11.635 1. x 1-1 12.35 6.1 12.99 5.49.782.32 x 1 36.25 13.36 3.69 9.89.252 1. x 1 44.49 13.33 4.69 1.41.527 Total score 15.21 29.91 97.5 23.35.52 Table 8. Comparison of the normalized perceived taste intensity score for sucrose between menopause women and pre-menopause women in the 5th-6th decades Sucrose Concentration (M) Menopause Pre-menopause 1. x 1-2 3.16 2.8 3.62 2.55.631.32 x 1-1 5.66 4.69 5.42 3.52.921 1. x 1-1 16.59 7.12 15.31 6.39.52.32 x 1 31.6 1.4 28.14 5.31.52 1. x 1 39.41 9.89 35.54 8.26.236 Total score 95.87 27.44 88.3 16.32.477 Table 9. Comparison of the normalized perceived taste intensity score for citric acid between menopause women and pre-menopause women in the 5th-6th decades Citric Acid Concentration (M) Menopause Pre-menopause.32 x 1-3 9.9 4.89 8.49 5.5.418 1. x 1-3 13.64 5.59 11.97 5.76.384.32 x 1-2 24.26 9.26 21.64 7.18.277 1. x 1-2 36.6 12.5 3.86 7.91.343.32 x 1-1 43.86 13.48 36.26 1.29.123 Total score 126.91 35.17 19.22 28.72.133 389
Table 1. Comparison of the normalized perceived taste intensity score for quinine HCl between menopause women and pre-menopause women in the 5th-6th decades Quinine HCl Concentration (M) Menopause Pre-menopause.32 x 1-5 3.68 3.8 4.38 3.93.72 1. x 1-5 3.71 4.62 5.5 5.43.366.32 x 1-4 12.71 1.43 9.61 7.73.452 1. x 1-4 21.49 9.8 21.33 1.4.843.32 x 1-3 37.24 11.61 32.13 1.58.166 1. x 1-3 43.12 11.5 38.8 1.2.179 Total score 121.96 38.44 111.2 32.68.34 Table 11. Comparison of age and percentage of pre-menopause between low and high salivation women in the 5th-6th decades Low salivation group High salivation group Age 51.59±5.95 years 49.43±3.86 years.195 Salivary flow rate 3.2±.8g/2 min 5.3±.9 g/2 min <.1 % of pre-menopause 41.2% 64.3%.285 * *: P-value by chi-square test Table 12. Comparison of the normalized perceived taste intensity score for NaCl between low and high salivation women in the 5th-6th decades NaCl Concentration (M) Low salivation group High salivation group 1. x 1-2 3.8 3.12 1.31 2.62.87.32 x 1-1 1.87 4.93 9.73 6.8.439 1. x 1-1 13.48 6.38 11.72 4.81.382.32 x 1 33.48 9.74 33.26 14.37.634 1. x 1 42.79 9.34 42.21 14.75.781 Total score 13.7 21.44 98.23 32.32.552 39
한국인여성에서노화에따른초역치미각강도의변화 Table 13. Comparison of the normalized perceived taste intensity score for sucrose between low and high salivation women in the 5th-6th decades Sucrose Concentration (M) Low salivation group High salivation group 1. x 1-2 4.6 2.67 2.58 2.44.228.32 x 1-1 6.72 4.73 4.11 2.56.99 1. x 1-1 17.46 7.3 14.6 5.49.153.32 x 1 29.9 8.54 29.12 7.99.937 1. x 1 37.58 8.8 37.21 9.89.812 Total score 95.72 25.64 87.9 17.36.32 Table 14. Comparison of the normalized perceived taste intensity score for citric acid between low and high salivation women in the 5th-6th decades Citric Acid Concentration (M) Low salivation group High salivation group.32 x 1-3 11.21 5.6 5.83 3.49.3 1. x 1-3 14.69 4.69 1.46 6..41.32 x 1-2 24.52 7.19 2.94 9.2.92 1. x 1-2 34.7 8.46 32.54 12.93.32.32 x 1-1 41.19 9.49 38.43 15.39.266 Total score 125.68 28.9 18.18 36.31.74 Table 15. Comparison of the normalized perceived taste intensity score for quinine HCl between low and high salivation women in the 5th-6th decades Quinine HCl Concentration (M) Low salivation group High salivation group.32 x 1-5 3.67 3.97 4.49 2.92.419 1. x 1-5 3.87 4.83 5.56 5.34.398.32 x 1-4 1.5 9.96 11.85 8.3.735 1. x 1-4 2.28 7.38 22.77 11.6.736.32 x 1-3 35.18 11.83 33.9 1.79.721 1. x 1-3 41.6 9.81 39.87 12.58.578 Total score 114.56 32.19 118.44 4.13.781 391
Ⅳ. 고찰 미각은여러가지전신질환과약물에의해서영향을받는것으로알려져있다. 미각에영향을주는대표적인전신질환으로는당뇨병, 신질환, 상기도감염, 만성부비동염, 중이염등이있으며, 미각에영향을주는약물로는항콜린제와항우울제와같은타액의분비를방해하는약물, 타액으로분비되는약물, 미각세포의생성을방해하는약물등이있다. 8,27,28) 이번연구에서는실험대상자의선정시에전신질환을가지고있거나약물을복용하는경우를비롯해서궤양성구강질병을가지고있거나가철성의치를사용하는경우도제외함으로써실험결과에영향을줄수있는인자를최대한배제하였다. 초역치미각강도의측정에있어서가장큰문제는미각강도를계량적으로나타낼수있는단위 (module) 가없다는것이다. 즉어떤미각물질이초역치수준에서나타내는맛의강도는단지개인의주관적느낌을물어보는것이외에는다른측정법이없기때문에미각강도의크기를객관적, 정량적으로나타내기가어려울뿐만아니라, 또한사람마다감각의인식과표현방법이다르기때문에개인과개인혹은집단과집단사이에초역치미각강도를비교하는것은대단히어려운일이다. 따라서미각강도는개인이느끼는느낌의크기를비계량적인규모 (nonmodulus magnitude) 로표시할수밖에없으며개인간의비교를위해서는개인이가지는인식과표현방법의차이를보정하기위한과정이필요하게된다. Bartoshuk 등 16) 은미각강도의측정에있어서개인이가지는인식과표현방법의차이를보정하기위하여 규모짝짓기법 을사용하였다. 이방법은원래 Stevens 와 Marks 29) 에의해서인간의감각기능을평가하기위해서처음고안된것인데, 한번의검사시기동안에두가지감각자극을섞어서주고이들자극에대한감지강도를동일한척도를사용하여나타내게하면이들두자극이동일한크기의규모추정을보인다는원리를응용한것이다. 즉, 소리자극과빛자극을섞어서주면서그크기를같은척도를이용하여나타내라고했을때약한소리는약한빛과그규모가짝지어지고, 강한소리는강한빛과그규모가짝지어진다고하였다. 또한이러한짝짓기가비교적안정적이기때문에어느한가지자극을기준으로다른자극에대한감지강도를추정할수있다고하였으며이러한원리를이용하여서로다른개체나집단간에도초역치수준의감각 강도를서로비교할수있다고하였다. 3) Bartoshuk 등 31) 은규모짝짓기법을이용한초역치미각강도검사법을사용해서두부외상과상기도감염환자에게서나타나는미각상실의정도를평가하기도하였는데, 이러한방법이미각상실을평가할수있는예민한방법이라고하였다. 국내에서는김등 32) 에의해서이러한방법이처음소개된바가있다. 저자는이번연구에서김등 32) 과 Bartoshuk 등 16,31) 이사용한것과같은방법의규모짝짓기법을이용하여초역치미각강도를측정함으로써측정의타당성을높이고연구결과의상호비교가가능하도록하였다. 저자의실험결과여성에있어서증령에따른초역치미각강도의변화는미각자극을일으키는미각물질의종류뿐만아니라미각물질의농도에따라다르게나타났다. 즉, 저농도의설탕수용액과저농도의염화나트륨수용액에대해서만증령에따른초역치미각강도의감소가나타났으며고농도의설탕수용액과고농도의염화나트륨수용액을비롯하여모든농도의구연산수용액과염산키니네수용액에대해서는증령에따른초역치미각강도의변화를보이지않았다. 이와같이증령과관련하여저농도의염화나트륨수용액과저농도의설탕수용액에대해서만초역치미각강도가감소한다는실험결과는외국에서보고된기존의연구에서는유사한사례를찾아볼수없는매우독특한것이라고생각되지만, 미각의변화가어느특정범위의농도에서현저히나타날수있다는점은이미 Bartoshuk 와 Marks 33) 에의해서언급된바가있다. Bartoshuk 와 Marks 33) 는미각감퇴환자에게서볼수있는미각변화의유형을 (1) 역치가증가하고초역치미각강도가감소한경우, (2) 역치근처에서의미각강도는증가되었으나초역치미각강도는정상인경우, (3) 역치는증가되었으나초역치미각강도는정상인경우, (4) 역치는정상이지만초역치미각강도가감소한경우등과같이 4 가지로분류한바가있다. 실제로 Bartoshuk 34) 에의하면방사선치료를받은직후에는미각역치가매우증가하고초역치미각강도가감소하였는데, 약 2 개월이경과한다음에미각역치는정상으로회복되었지만초역치미각강도는여전히감소된상태에있었다고하였다. 그러나저자의실험결과를비롯하여앞서보고된여러선학들의연구에서도증령에따른초역치미각강도의변화에관해서저자들마다실험결과가다르게나왔기때문에초역치미각강도의측정을통하여미각기능의변화를평가하기에는측정법과평가기준에 392
한국인여성에서노화에따른초역치미각강도의변화 있어서아직객관적자료가충분치못하다고볼수있다. 그럼에도불구하고 Figure 5와 6에서보는바와같이각농도별미각강도점수 (perceived intensity score) 를모두합한총미각강도점수의분포도를그려보면염화나트륨과설탕에대한초역치미각강도가노인에게서일관되게낮게나타나고있음을알수있다. 그러나이러한경향을구연산과염산키니네에서는볼수없기때문에신맛과쓴맛에대한초역치미각강도는증령에의한영향을받지않는것으로볼수있다 (Fig. 7, 8). 따라서저자의연구에의하면증령에의한초역치미각강도의감소가짠맛과단맛에대해서만어느정도일어나고있다고볼수있으며, 이러한변화는특히저농도의미각수용액에서두드러진다고하겠다. 노화로인해서초역치미각강도가감소하는기전은아직잘이해되지않고있다. 다만일부의학자들은노인에게서미각유두와미뢰의수가감소하는것이미각기능의감퇴와관련된다고하였지만또다른학자들은 그러한변화를관찰할수없었다고하였다. 35-38) 어떤학자는미뢰의상실보다는미각세포막에있는이온통로와수용체의변화가미각기능의상실과더밀접한관계가있다는제안을하기도하였다. 8) 일반적으로폐경기여성은폐경전여성에비해타액분비량이감소되는것으로알려져있으며이로인해치아우식증이증가되고구강감각이상이나미각변화의유병율이증가할수있다고하였다. Wardrop 등 39) 의보고에의하면폐경전여성이구강불편감을호소하는경우가 6% 에불과한반면에폐경여성에서는 46% 에이른다고하였다. 또한 Friedlander 4) 는폐경여성에서타액의결핍, 치아우식증, 감각이상, 미각변화, 위축성치은염, 치주염등과같은임상적문제가발생할수있음을언급하기도하였다. 저자는폐경이초역치미각강도에미치는영향을측정하기위해서 4-5 대여성을폐경군과폐경전군으로나누어서타액분비량과네가지기본미각에대한농도별초역치미각강도를두군사이에비교하여 Total Intensity 18 16 14 12 1 8 6 4 2 1 2 3 4 Arbitrary case number Total Intensity 25 2 15 1 5 1 2 3 4 Arbitrary case number Fig. 5. Distribution of subjects according to the total taste intensities for NaCl Fig. 7. Distribution of subjects according to the total taste intensities for citric acid Total Intensity 18 16 14 12 1 8 6 4 2 1 2 3 4 Arbitrary case number Total Intensity 25 2 15 1 5 1 2 3 4 Arbitrary case number Fig. 6. Distribution of subjects according to the total taste intensities for sucrose Fig. 8. Distribution of subjects according to the total taste intensities for quinine HCl 393
보았다. 폐경군의타액분비량이 3.77±1.37 g 으로서폐경전군의 4.45±1.33 g 에비해감소되어있었다. 그러나네가지기본미각에대한농도별초역치미각강도는두군사이에유의한차이를발견할수없었다. 이러한결과가 Delilbasi 등 41) 의연구와일치하는것이기는하였지만폐경군에서폐경후의경과시간이너무다양하기때문에폐경으로인한단기적영향과장기적영향을구분하지못한것이실험결과의해석에제한을초래하고있다. 타액은미각물질의용매가되고미각물질을미각세포에전달하는기능이있을뿐만아니라, Temmel 등 42) 과 Hershkovich 등 43) 의연구에의하면타액의어떤성분이미각작용에관여하는것으로도추정되기때문에타액과미각은매우밀접한관련성이있다고볼수있다. 저자는타액의분비량이초역치미각강도에미치는영향을평가하기위하여 4-5 대여성에서타액분비량이상대적으로많은군과적은군사이에미각강도를비교하였다. 2 분동안분비된전타액의량은 1.4 g~7. g ( 평균 4.13±1.39 g) 의분포를나타내어개인별로타액분비량의상당한차이를보였지만타액분비량이상대적으로많은군 (>4g/2 min) 과적은군 ( 4g/2 min) 사이에서미각강도의변화는거의나타나지않았다. 다만구연산수용액의낮은농도에서만타액분비량이적은군에서미각강도가높게나타났을뿐이다. 타액분비량이적은군에서저농도의구연산수용액에대한미각강도가높은이유를정확히설명하기는어려우나, 아마도저자의견해로는신맛을느끼게하는수소이온의농도가타액의완충력에의해서영향을받기때문에나타난결과로추정된다. 즉, 타액분비가많은경우에는타액의완충력이풍부하기때문에수소이온의농도가떨어져서신맛의강도가감소할수있을것으로생각된다. 이와같이타액저분비자와고분비자사이에미각강도의차이가신맛을제외하고는거의나타나지않은이유가이번연구에참여한실험대상이모두구강건조증의증상이없는건강한여성이었다는점과무관하지않을것으로생각된다. 이에반해구강건조증환자를대상으로한다른선학들의연구에서는구강건조증환자에게서미각민감도의감소나미각만족도의감소가나타났다고한바가있으며, 또한구강건조증환자들이미각기능의변화를호소하는경우도있다 42,44) 고하였기때문에향후에는구강건조증의증상을나타내는환자를대상으로초역치미각강도의변화를측정해볼필요가있을것으로생각된다. V. 결론 저자는 2 대 (3 명, 평균연령 25.1±1.71 세 ) 와 4-5 대 (31 명, 평균연령 5.8±5.1 세 ) 의건강한한국인여성을대상으로염화나트륨, 설탕, 구연산, 염산키니네수용액에대한초역치미각강도를측정한다음두군사이의차이를비교하였으며, 4-5 대여성에대해서는또한폐경의여부와타액분비량의다과에따른차이를비교하여다음과같은결론을얻었다. 1. 한국인 4-5 대여성은 2 대여성에비해저농도의염화나트륨수용액과저농도의설탕수용액에대한초역치미각강도가감소되었으며, 고농도의염화나트륨수용액과고농도의설탕수용액, 그리고모든농도의구연산수용액과염산키니네수용액에서는차이가없었다. 2. 한국인 4-5 대여성에서폐경으로인한초역치미각강도의변화는나타나지않았다. 3. 한국인 4-5 대여성에서타액분비량의다과에따른초역치미각강도의변화가염화나트륨수용액, 설탕수용액, 염산키니네수용액에대해서는나타나지않았다. 4. 한국인 4-5 대여성에서타액분비량이적은군이많은군에비해저농도의구연산수용액에대한초역치미각강도가높게나타났다. 참고문헌 1. 이종흔, 김중수. 구강생리학. 4 판, 군자출판사, 서울, 1994, pp.211-233. 2. Schiffman SS. Taste and smell losses with age. Bol Assoc Med P Rico 1991;83(9):411-414. 3. Schiffman SS. Taste and smell in disease. N Eng J Med 1983;38:1275-1279,1337-1343. 4. Mattes RD, Cowart BJ. Dietary assessment of patients with chemosensory disorders. J Am Diet Assoc 1994;94:5-56. 5. Duffy VB, Backstrand JR, Ferris AM. Olfactory dysfunction and related nutritional risk in free-living, elderly women. J Am Diet Assoc 1995;95:879-886. 6. Schiffman SS, Wedral E. Contribution of taste and smell losses to the wasting syndrome. Age Nutr 1996;7:16-12. 7. Chávez EM, Ship JA. Sensory and motor deficits in the elderly: Imapct on oral health. J Public Health Dent 2;6(4):297-33. 394
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common marmoset. Chem Senses 21;26:1-6. 38. Segovia C, Hutchinson I, Laing DG, Jinks AL. A quantitative study of fungiform papillae and taste pore density in adults and children. Dev Brain Res 22;138:135-146. 39. Wardrop RW, Hailes J, Burger H, Reade PC. Oral discomfort at menopause. Oral Surg 1989;67:535-54. 4. Friedlander AH. The physiology, medical management and oral implications of menopause. J Am Dent Assoc 22;133:73-81. 41. Delilbasi C, Cehiz T, Akal UK, Yilmaz T. Evaluation of gustatory function in postmenopausal women. Br Dent J 23;194(8):447-449. 42. Temmel AFP, Quint C, Schickinger-Fischer B, Hummel T. Taste function in xerostomia before and after treatment with a saliva substitute containing carboxymethylcellulose. J Otolaryngol 25;34(2): 116-12. 43. Hershkovich O, Nagler RM. Biochemical analysis of saliva and taste acuity evaluation in patients with burning mouth syndrome, xerostomia and/or gustatory dusturbances. Arch Oral Biol 24;49: 515-522. 44. Ikebe K, Sajima H, Kobayashi S, Hata K, Morii K, Nokubi T, et al. Association of salivary flow rate with oral function in a sample of community-dwelling older adults in Japan. Oral Surg Oral Med Oral Pathol 1992;94(2):184-19. - ABSTRACT - Suprathreshold Taste Intensities for Salt, Sucrose, Citric Acid, and Quinine HCl in Korean Women Sang-Chul Yoon, D.D.S.,M.S.D.,Ph.D., Yun-Kyung Hur, D.D.S.,M.S.D.,Ph.D., Jae-Kap Choi, D.D.S.,M.S.D.,Ph.D. Department of Oral Medicine, School of Dentistry Kyungpook National University Daegu, Korea The aim of this study was to measure the suprathreshold taste intensity for NaCl, sucrose, citric acid, and quinine HCl in elderly Korean women using a whole-mouth, sip-and-spit procedure, employing the method of magnitude matching. The results were analysed in terms of aging, menopause, and salivary flow rate. 31 elderly women (mean age; 5.8±5.1 years) and 3 young women (mean age; 25.1±1.71 years) were included for the study. Subjects were instructed to give nonmodulus magnitude estimates to the intensities of five concentrations each of sucrose, NaCl, citric acid, and quinine HCl; distilled water; 6 loudness level of a 1,-Hz tone, using the same 9-point intensity scale. Each of the 21 taste stimuli and 6 auditory stimuli are presented in random order twice. The auditory function is used to assess the absolute intensity function of the subject's taste system. The results were as follows; 1. Comparing to young women, elderly women showed decreased taste intensities for lower concentration solutions of NaCl and sucrose. However, other solutions didn't show any difference in taste intensities between young and elderly women. 2. There were not significant difference in perceived taste intensities for NaCl, sucrose, citric acid, and quinine HCl between menopause and pre-menopause women in elderly women group. 3. There were not significant difference in perceived taste intensities for NaCl, sucrose, and quinine HCl between low salivation women and high salivation women in elderly women group. 4. The low salivation women in elderly group showed higher taste intensity for low concentration citric acid than high salivation women. Key words: Aging, Suprathreshold taste intensity, Korean women, Salivary flow rate, Menopause 396