Leng Sean X, Hung Will, Cappola Anne R, Yu Qilu, Xue Qian-Li, Fried Linda P
Division of Geriatric Medicine and Gerontology, 5505 Hopkins Bayview Circle, Johns Hopkins School of Medicine, Baltimore, MD 21224, USA.
J Gerontol A Biol Sci Med Sci. 2009 Apr;64(4):499-502. doi: 10.1093/gerona/gln047. Epub 2009 Feb 27.
Elevated white blood cell (WBC) counts and decreased insulin-like growth factor-1 (IGF-1) levels are individually associated with frailty in older adults. WBC subpopulations are known to produce IGF-1 and express IGF-1 receptors in vitro. However, in vivo relationships between WBC and IGF-1 and their joint contribution to frailty have not been investigated.
Baseline data from 696 community-dwelling older women in the Women's Health and Aging Study I were included in this cross-sectional analysis. Multivariate linear regression analysis was performed to assess the relationship between WBC counts and IGF-1 levels. Odds ratios (ORs) for frailty were evaluated across tertiles of WBC counts and IGF-1 levels, adjusting for age, race, education, body mass index, and smoking.
WBC counts correlated with IGF-1 levels (Spearman coefficient: .10, p < .01). Compared with participants in the low WBC and high IGF-1 tertiles (reference group), those in the low WBC and low IGF-1 tertiles had OR of 2.33 for frailty (95% confidence interval [CI]: 1.04-3.65, p < .05), those in the high WBC and high IGF-1 tertiles had OR of 3.86 (95% CI: 1.13-4.07, p < .01), and those in the high WBC and low IGF-1 tertiles had OR of 3.61 (95% CI: 1.64-4.97, p < .01), adjusting for covariates.
These findings demonstrate in vivo correlation between WBC and IGF-1. They suggest U-shaped joint associations of WBC and IGF-1 with frailty, with the strongest association at adverse levels of both. They also provide a basis for further investigation into the complex immune-endocrine dysregulations in frailty.
白细胞（WBC）计数升高和胰岛素样生长因子-1（IGF-1）水平降低分别与老年人的衰弱相关。已知白细胞亚群在体外可产生IGF-1并表达IGF-1受体。然而，白细胞与IGF-1之间的体内关系及其对衰弱的共同作用尚未得到研究。
纳入妇女健康与衰老研究I中696名社区居住老年女性的基线数据进行横断面分析。采用多变量线性回归分析评估白细胞计数与IGF-1水平之间的关系。在白细胞计数和IGF-1水平的三分位数范围内评估衰弱的比值比（OR），并对年龄、种族、教育程度、体重指数和吸烟情况进行校正。
白细胞计数与IGF-1水平相关（斯皮尔曼系数：0.10，p < 0.01）。与白细胞计数低且IGF-1水平高的三分位数组参与者（参照组）相比，白细胞计数低且IGF-1水平低的三分位数组参与者衰弱的OR为2.33（95%置信区间[CI]：1.04 - 3.65，p < 0.05），白细胞计数高且IGF-1水平高的三分位数组参与者衰弱的OR为3.86（95% CI：1.13 - 4.07，p < 0.01），白细胞计数高且IGF-1水平低的三分位数组参与者衰弱的OR为3.61（95% CI：1.64 - 4.97，p < 0.01），对协变量进行了校正。
这些发现证明了白细胞与IGF-1之间的体内相关性。它们提示白细胞和IGF-1与衰弱呈U型联合关联，在两者均处于不利水平时关联最强。它们还为进一步研究衰弱中复杂的免疫 - 内分泌失调提供了基础。
