- 期刊
Paradoxes with Weight Disorders for Health Systems
體重失調矛盾
摘要
身體質量指數（BMI）為公共衛生與臨床醫學中肥胖判定的常用依據。然而它的使用卻也造成一些矛盾及誤解，例如體組成失調（BCD）的判定爭論，特別是用在以肌肉質量為評估指標之肌少症的早期偵測並不適當。在生命週期中，身體組成會隨著性別、年齡與種族而有所差異，而身體組成異常疾病通常是導因於個人相關營養需求失調及慢性疾病。譬如在代謝異常的糖尿病患中，肌肉、脂肪甚至骨質的分布可能是影響其代謝異常發展的重要機轉之一。因此，理想的體脂肪量及分布與孩童的發展、母親健康及健康老化的機制密切相關。整體而言，肥胖所導致的經濟及社會成本是伴隨BMI的增加而提高，但BMI和死亡率卻是呈現J或是U型的關係。在慢性病患中，例如糖尿病、腎衰竭或是心衰竭，較多體脂肪的人可能有較低的死亡風險；可能是因為較肥胖者有較多的心肌維持生命或者是因為脂肪細胞阻絕環境汙染因子對肌肉細胞的傷害。這些因素可能解釋健康照護系統中，體脂肪較高的老人，其存活率相對較高。因此，因果相關倒置的現象不應該被忽略。另一方面，熱量缺乏的幼童，可能在未獲得足夠能量前即死亡。在這樣的觀點中，人類比我們自己想像的還要脆弱。所幸，我們逐漸了解BMI及健康關係。
並列摘要
The body mass index (BMI) has served public health and clinical medicine well in the recognition of obesity. However, its use has generated some instructive paradoxes and misunderstandings which argue for the appreciation of body compositional disorders (BCD) as such and, in particular, for the parallel evaluation of muscle mass with a definition of 'orthosarcal' conditions to enable the early detection of sarcopenia. Across the life-span, and with gender and ethnic differentials, BCD is basic to the full spectrum of nutritionally-related disorders and diseases. In the case of metabolic diseases like diabetes, muscle, fatness and its distribution, and even bone seem to play pathogenetic roles. Optimal body fat and distribution are relevant to child development, maternal health and healthy ageing, with much more to learn about the mechanisms. The economic and societal costs of obesity tend to increase progressively with the BMI, but the health outcomes, at least for mortality, are J-or U-shaped. With some established chronic diseases, like diabetes, renal failure or cardiac failure, overfatness may be protective; sometimes this may be because contaminant fat-soluble endocrine disrupters are segregated in fat tissue. This means that some of the relatively favourable survival in the elderly who have more body fat is at the expense of the health care system. Younger children with chronic energy deficiency, on the other hand, may succumb before expenditure saves them. In these respects, our species is more vulnerable than we have thought. Fortunately, a better understanding of BMI and health is emerging.