Comorbidity is a better predictor of impaired immunity than chronological age in older adults.

Objectives: To determine whether high level of comorbidity, measured using a standardized instrument, can predict impaired immunity in older adults.

Setting: Geriatric outpatient Clinic and Nursing Home Care Unit of Veterans Affairs Greater Los Angeles Healthcare System.

Participants: Fifteen men aged 51 to 95 with varying levels of chronic illness.