The nurse working with oncology clients understands that which age-related change increases the older client's susceptibility to infection during chemotherapy?

Rationale: A. Diminished nutritional stores can contribute to slower healing and overall weakness, but they are not the primary reason older adults are more susceptible to infection during chemotherapy. Nutritional depletion affects recovery but not directly the immune cell function. B. Poor physical reserves affect the older adult’s ability to tolerate treatment side effects and recover from fatigue, but they do not directly cause immunosuppression or increased infection risk. C. Existing cognitive deficits can interfere with the client’s ability to follow infection-control precautions or report early signs of illness, but they are not the physiological cause of increased susceptibility. D. Decreased immune function is the primary age-related factor that increases susceptibility to infection during chemotherapy. Aging leads to a natural decline in bone marrow activity, T-cell production, and immune response efficiency—a process known as immunosenescence. When combined with chemotherapy-induced myelosuppression (neutropenia), this significantly compromises the body’s ability to fight infection, placing older adults at greater risk for sepsis and delayed recovery.