Kuo Hsu-Ko, Bean Jonathan F, Yen Chung-Jen, Leveille Suzanne G
7 Chung-Shan S. Road, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
J Gerontol A Biol Sci Med Sci. 2006 Apr;61(4):380-7. doi: 10.1093/gerona/61.4.380.
Chronic inflammation, measured by interleukin-6, predicts incident disability among elderly people. However, little is known about the relation of C-reactive protein (CRP) to disability.
Participants (>60 years old, N = 1680) were from the National Health and Nutrition Examination Survey 1999-2002. Disability in activities of daily living (ADL), instrumental activities of daily living (IADL), leisure and social activities (LSA), lower extremity mobility (LEM), and general physical activities (GPA) was obtained by self-report. Peak muscle power was the product of isokinetic peak leg torque and peak force velocity. Functional limitations were evaluated via habitual walking speed, which was obtained from a 20-foot timed walk. CRP levels were quantified by using latex-enhanced nephelometry.
Elevated CRP levels were associated with disability in IADL, LSA, LEM, and GPA, independent of basic demographics, chronic medical diseases, health behaviors, as well as nutritional markers. The corresponding odds ratios of disability for each standard-deviation increase in natural-log-transformed CRP were 1.18 (95% confidence interval [CI], 1.02-1.35), 1.18 (95% CI, 1.00-1.39), 1.17 (95% CI, 1.03-1.33), and 1.17 (95% CI, 1.05-1.31), respectively. The relationship diminished after additional adjustment of leg power and/or walking speed, meaning that impairment in leg power and limitations in gait speed likely mediate the association between CRP and disability. CRP had an inverse relationship to leg power and walking speed. Likewise, additional adjustment for leg power substantially diminished the association between CRP and walking speed, suggesting a mediating effect of power between CRP and gait speed.
Independent of chronic diseases, elevated CRP is associated with multiple domains of disability through mediation of muscle power, habitual gait speed, or both. Future research is needed to understand CRP as a risk factor for disability in older populations.
通过白细胞介素-6衡量的慢性炎症可预测老年人发生残疾的情况。然而，关于C反应蛋白（CRP）与残疾之间的关系，人们了解甚少。
参与者（年龄>60岁，N = 1680）来自1999 - 2002年的国家健康与营养检查调查。通过自我报告获取日常生活活动（ADL）、工具性日常生活活动（IADL）、休闲和社交活动（LSA）、下肢活动能力（LEM）以及一般身体活动（GPA）方面的残疾情况。峰值肌肉力量是等速峰值腿部扭矩与峰值力速度的乘积。通过20英尺定时步行得出的习惯步行速度来评估功能受限情况。使用乳胶增强比浊法对CRP水平进行定量。
CRP水平升高与IADL、LSA、LEM和GPA方面的残疾相关，独立于基本人口统计学特征、慢性疾病、健康行为以及营养指标。自然对数转换后的CRP每增加一个标准差，残疾的相应比值比分别为1.18（95%置信区间[CI]，1.02 - 1.35）、1.18（95% CI，1.00 - 1.39）、1.17（95% CI，1.03 - 1.33）和1.17（95% CI，1.05 - 1.31）。在进一步调整腿部力量和/或步行速度后，这种关系减弱，这意味着腿部力量受损和步态速度受限可能介导了CRP与残疾之间的关联。CRP与腿部力量和步行速度呈负相关。同样，对腿部力量进行额外调整后，CRP与步行速度之间的关联大幅减弱，表明力量在CRP与步态速度之间起中介作用。
独立于慢性疾病，CRP升高通过肌肉力量、习惯步态速度或两者的中介作用与多个残疾领域相关。需要进一步研究以了解CRP作为老年人群残疾风险因素的情况。
