Ferrucci L, Harris T B, Guralnik J M, Tracy R P, Corti M C, Cohen H J, Penninx B, Pahor M, Wallace R, Havlik R J
Geriatric Department, I Fraticini, National Research Institute (INRCA), Florence, Italy.
J Am Geriatr Soc. 1999 Jun;47(6):639-46. doi: 10.1111/j.1532-5415.1999.tb01583.x.
The serum concentration of interleukin 6 (IL-6), a cytokine that plays a central role in inflammation, increases with age. Because inflammation is a component of many age-associated chronic diseases, which often cause disability, high circulating levels of IL-6 may contribute to functional decline in old age. We tested the hypothesis that high levels of IL-6 predict future disability in older persons who are not disabled.
Participants at the sixth annual follow-up of the Iowa site of the Established Populations for Epidemiologic Studies of the Elderly aged 71 years or older were considered eligible for this study if they had no disability in regard to mobility or in selected activities of daily living (ADL), and they were re-interviewed 4 years later. Incident cases of mobility-disability and of ADL-disability were identified based on responses at the follow-up interview. Measures of IL-6 were obtained from specimens collected at baseline from the 283 participants who developed any disability and from 350 participants selected randomly (46.9%) from those who continued to be non-disabled.
Participants in the highest IL-6 tertile were 1.76 (95% CI, 1.17-2.64) times more likely to develop at least mobility-disability and 1.62 (95% CI, 1.02-2.60) times more likely to develop mobility plus ADL-disability compared with to the lowest IL-6 tertile. The strength of this association was almost unchanged after adjusting for multiple confounders. The increased risk of mobility-disability over the full spectrum of IL-6 concentration was nonlinear, with the risk rising rapidly beyond plasma levels of 2.5 pg/mL.
Higher circulating levels of IL-6 predict disability onset in older persons. This may be attributable to a direct effect of IL-6 on muscle atrophy and/or to the pathophysiologic role played by IL-6 in specific diseases.
白细胞介素6（IL-6）是一种在炎症中起核心作用的细胞因子，其血清浓度会随着年龄增长而升高。由于炎症是许多与年龄相关的慢性疾病的一个组成部分，而这些慢性疾病常常导致残疾，因此循环中高水平的IL-6可能会导致老年人功能衰退。我们检验了这样一个假设，即高水平的IL-6可预测未残疾的老年人未来出现残疾的情况。
在爱荷华州老年流行病学研究既定人群研究站点进行的第六次年度随访中，年龄在71岁及以上且在行动能力或选定的日常生活活动（ADL）方面无残疾的参与者被认为符合本研究条件，并在4年后再次接受访谈。根据随访访谈中的回答确定行动能力残疾和ADL残疾的发病情况。从283名出现任何残疾的参与者以及从继续未残疾的参与者中随机选择的350名参与者（46.9%）在基线时采集的标本中获取IL-6的测量值。
与IL-6水平最低的三分位数组相比，IL-6水平最高的三分位数组的参与者发生至少行动能力残疾的可能性高1.76倍（95%CI，1.17 - 2.64），发生行动能力加ADL残疾的可能性高1.62倍（95%CI，1.02 - 2.60）。在对多个混杂因素进行调整后，这种关联的强度几乎没有变化。在整个IL-6浓度范围内，行动能力残疾风险的增加是非线性的，当血浆水平超过2.5 pg/mL时风险迅速上升。
循环中较高水平的IL-6可预测老年人残疾的发生。这可能归因于IL-6对肌肉萎缩的直接作用和/或IL-6在特定疾病中所起的病理生理作用。
