鑑別台灣青少年代謝症候群及其成分因子之肥胖人體測量學指標之評估

Evaluation of Anthropometric Indicators of Obesity in Identifying Metacolic Syndrome and its factors among Adolescent in Taiwan

金郁婷(Yu-Ting Chin)

指導教授 ： 李建宏

高雄醫學大學/健康科學院/公共衛生學系公共衛生學碩士班/碩士(2016年)

摘要

研究背景與目的：身體質量指數(Body Mass Index；BMI)為當前最常用以評定肥胖體位之方法，然而，此指標無法合適地區辨腹部肥胖(abdominal obesity或稱為central obesity)與一般型肥胖(general obesity)之體型差異。近年來，多位學者提出數個新式肥胖指數(obesity index)，試圖使用體位資料鑑別或預測心血管代謝障礙之發展。儘管多項新式體型指數相繼被提出，其於青少年群體鑑別代謝症候群與成分因子之效果仍屬未知。此外，此些新興之肥胖指數當中，2012年提出之身體體型指數(a body shape index；ABSI)被認為為一種可以有效控制BMI及身高之干擾後，能準確地鑑別代謝症候群與其成分因子的新式體型指數。然而，近年的研究顯示，ABSI在青少年的群體測量到與血壓值無法解釋之負相關。基於上述之研究背景與問題，本研究有二個目的：1) 評析身體體型指數(ABSI)是否應依研究族群之異質性適當修改指標參數；2) 綜合性比較各種肥胖指標及身體體型指數(ABSI)鑑別青少年代謝症候群及其成分因子之能力。

研究方法：本研究以具全國青少年代表性之國民營養調查資料(Nutrition and Health Survey in Taiwan; NAHSIT)為作為發展資料集(development dataset)，並以南台灣國中生之多層次代謝症候群研究(multilevel Risk Profiles for adolescent Metabolic Syndrome; mRP-aMS study)作為驗證資料集(validation dataset)，評估BMI、腰圍(waist circumference, WC)、臀圍(hip circumference, HC)、腰臀比(waist-hip ratio, WHR)、腰高比(waist-height ratio, WHtR)、身體肥胖指數(body adiposity index, BAI)、腹部體積指數(abdominal volume index, AVI)、錐度指數(conicity index, CI)、體圓度指數(body roundness index, BRI)和ABSI，以及以主成份分析(principle component analysis)獲得之二個組合性肥胖指標，亦即主成份一與主成份二(principle component 1 and 2; PC1 and PC2)等12項肥胖指數對於青少年代謝症候群及其成分因子之鑑別能力。本研究採用國際糖尿病聯合會之標準定義青少年代謝症候群，使用接收者操作特徵曲線下面積(area under the receiver operating characteristic curve)，以及排序等級總合分數，評估12項肥胖指數對於代謝症候群與其成分因子異常之鑑別能力。本研究以多元邏輯斯回歸模式(multiple logistic regression)評估鑑別力較佳之肥胖指數以及ABSI對於代謝症候群與其成分因子之危險對比值(odds ratio, OR)。

研究結果：原始ABSI於NAHSIT與mRP-aMS之研究群體皆與BMI及身高顯著相關(P <0.05)，無法控制此二變數之干擾。性別對於BMI與腰圍之關聯性具有顯著之交互作用(P for interaction <0.001)。NAHSIT研究群體之鑑別分析顯示，男性學童前25%最佳肥胖指標為BMI、AVI與WC，排序等級總合分數分別為，43, 40.5, 40。女性學童則為GIRL-PC1、WHtR、BRI及BMI，排序等級總合分數分別為，40, 37, 37, 35。於mRP-aMS研究群體之中，前25%最佳肥胖指標亦有相似的結果：男性為BMI、BOY-PC1與AVI，排序等級總合分數分別為，41, 38, 37；女性為AVI、WHtR、BRI與GIRL-PC1，排序等級總合分數分別為，39, 37, 37,34。男女第一主成份對於代謝症候群均顯現最高的關聯性(增加一單位PC分數關聯性之OR分別如下：NAHSIT研究群體，BOY-PC1, OR=1.86; GIRL-PC1=1.65；mRP-aMS研究群體，BOY-PC1, OR=1.92, GIRL-PC1=1.91, all P <0.001)。此外，代謝症候群與各研究群體發展出之ABSI具有最低之關聯性(NAHSIT研究群體：男性OR=1.02，女性OR=1.02；mRP-aMS研究群體：男性OR=1.01，女性OR=1.02；all P ≤0.016)。

研究結論：ABSI公式中的參數應隨年齡、性別與族群特性而作適當地修正。關於鑑別台灣青少年代謝症候群之肥胖指數，BMI與AVI為男性學童合適之指標；WHtR與BRI為女性學童合適之指標。由於WHtR與BRI對於代謝症候群各成分因子之鑑別力相同，本研究建議採用計算較簡便的WHtR為女性學童之肥胖指數。雖然重組性的肥胖指標(PC1)不易解釋，然而其與代謝症候群具最大之風險關聯性突顯考慮綜合性肥胖指數之重要性。ABSI可能不適合作為評估青少年心血管代謝障礙之肥胖指數。此外，當前常用之BMI仍然合適作為鑑別台灣男性青少年代謝症候群與其異常成分因子之肥胖指標。

關鍵字

肥胖 ； 肥胖指數 ； 青少年 ； 代謝症候群 ； 身體質量指數 ； 身體體型指數

並列摘要

Introduction and objectives: Body Mass Index (BMI) is the most common use index of obesity currently; however, BMI provide no information on the distribution of adipose tissue, namely, we can’t distinguish general obesity and central obesity from BMI. Hence, many anthropometric related obesity indices were developed recently for better discrimination of cardiometabolic disorders. A Body Shape Index was first proposed by Krakuar & Krakuar in 2012 with the advantage of controlling potential confounders (BMI & height); nonetheless, a Portuguese study had found a counter-intuitive association between ABSI and blood pressure in adolescent which we think the body shape of adolescents is different from that of adults and, therefore, using the same set of scaling exponents introduces confounding. This study aims, first, whether the scaling exponents for standardizing WC for BMI and height in Taiwanese adolescents and compare them with the findings from the original ABSI. The second objective is to compare the ability to identify metabolic syndrome (Mets) and its factors among 12 obesity indices comprehensively.
Methods: There are two representative subjects in this study: Nutrition and Health Survey in Taiwan (NAHSIT) which was nationwide as development dataset and monitor Multilevel Risk Profiles for Adolescent Metabolic Syndrome (mRP-aMS study) from southern Taiwan as validation dataset, in order to evaluate the discrimination of Body Mass Index, Waist circumference, Hip circumference, Waist-to-Hip Ratio, Waist-to Height Ratio, Body Adiposity Index, Abdominal Volume Index, Conicity Index, Body Roundness Index, A Body Shape Index and two composite obesity indices (principle component 1 and 2; PC1 and PC2) found by principle component analysis. We used the criteria from International Diabetes Federation to diagnose adolescent Mets and area under the receiver operating characteristic curve to assess the discrimination; moreover, we picked up obesity indices of top 25% of discrimination by sorting rank sum. In this study, multiple logistic regression was used to calculate the odds ratio (OR) between 12 obesity indices and Mets.
Results: The original ABSI had high correlation coefficient in both NAHSIT and mRP-aMS research group (P <0.05), suggesting incapable of controlling those confounders. Sex had significant interaction on the relation of BMI and waist circumference (P for interaction <0.001). In NAHSIT research group showed the top 25% of discrimination obesity indices of male teenagers were BMI, AVI and BOYPC1 whose rank sum was 43, 40.5 and 40, respectively; meanwhile, GIRLPC1, WHtR, BRI and BMI were chosen in female teenagers and each of the rank sum was 40, 37, 37 and 35. Similar results were found in mRP-aMS research group, that was the top 25% of discrimination obesity indices in male teenagers were BMI, BOYPC1 and AVI, whose rank sum was 41, 38 and 37; while female teenagers had AVI, WHtR, BRI and GIRLPC1 and the rank sum was 39, 37, 37 and 34, repestively. BOYPC1 and GIRLPC1 had the highest Odds Ratio to Mets among 12 obesity indices (In NAHSIT dataset, BOYPC1, OR=1.86; GIRL-PC1=1.65; In mRP-aMS study, BOYPC1, OR=1.92, GIRLPC1=1.91, all P <0.001). Besides, ABSI developed from each research group had the lowest OR in Mets (In NAHSIT dataset, male OR=1.02, female OR=1.02；mRP-aMS study, male OR=1.01, female OR=1.02; all P ≤0.016).

Conclusion: We found ABSI should be modified the scaling exponents according to age, sex and different demographic characteristics population. As the indicators of discriminate Taiwan adolescents Mets, BMI and AVI were suitable for male teenagers; on the other hand, for female teenagers WHtR and BRI were appropriate. ABSI may not be an appropriate obesity index for adolescents. Moreover, BMI seems still to be an effective obesity index for identifying teenage cardiometabolic disorders. Because of the resemble discrimination for Mets and its factors in WHtR and BRI, we recommend WHtR due to simpler calculation. Composite obesity index was uneasy to explain, however, it had the highest OR for Mets and highlight the importance of concerning composite indices. ABSI may be inadequate for predicting Mets in adolescents. In addition, BMI which is currently used is still enough for identifying the Mets and its factors in Taiwan male adolescents.

並列關鍵字

obesity ； obesity indices ； adolescent ； Metabolic syndrome (Mets) ； Body Mass Index (BMI) ； A Body Shape Index (ABSI)

參考文獻

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