Which patient characteristic is NOT associated with an increased likelihood of CINV?

The characteristic that is not associated with an increased likelihood of chemotherapy-induced nausea and vomiting (CINV) is being older than 50 years. Research has shown that age can play a role in the experience of CINV, with younger patients often reporting higher incidences of nausea and vomiting in response to chemotherapy. This can be attributed to various factors, including biological differences, psychological responses, and how younger patients' bodies metabolize chemotherapy drugs.

In contrast, characteristics such as female gender, a history of low alcohol intake, and previous chemotherapy exposure have been linked to a higher risk of developing CINV. Women generally have higher rates of CINV compared to men due to hormonal influences and other factors. A history of alcohol consumption can alter the body's response to certain medications, potentially leading to an increased risk of nausea and vomiting. Additionally, patients who have undergone chemotherapy in the past are more likely to experience CINV with subsequent treatments due to sensitization of emetic pathways.

Therefore, being older than 50 years is not a risk factor for CINV as opposed to the other characteristics listed.