White blood cell counts, insulin-like growth factor-1 levels, and frailty in community-dwelling older women

J Gerontol A Biol Sci Med Sci. 2009 Apr;64(4):499-502. doi: 10.1093/gerona/gln047. Epub 2009 Feb 27.


Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aging / metabolism
  • Biomarkers / analysis*
  • Body Mass Index
  • Cross-Sectional Studies
  • Female
  • Frail Elderly*
  • Geriatric Assessment
  • Humans
  • Insulin-Like Growth Factor I / analysis*
  • Leukocyte Count*
  • Odds Ratio
  • Probability
  • Residence Characteristics
  • Risk Assessment
  • Sensitivity and Specificity
  • Women's Health


  • Biomarkers
  • Insulin-Like Growth Factor I