Which factor increases Donald's risk for influenza-related complications?

Obesity is a significant factor that increases the risk for influenza-related complications. Individuals with obesity have a higher likelihood of experiencing severe illness when infected with influenza due to various physiological reasons. The presence of excess body fat can impact the immune system's ability to respond adequately to infections, leading to a dysregulated inflammatory response. This inflammatory response can exacerbate symptoms and contribute to complications like pneumonia or respiratory failure.

In addition to compromised immune function, obesity is often associated with other health conditions, such as diabetes and cardiovascular diseases, which can further increase the risk of serious outcomes from influenza. This heightened vulnerability emphasizes the importance of preventive measures, such as vaccination, for individuals who are obese.

Other factors like age are also important, as young children and the elderly are typically more susceptible to complications from influenza, but in this context, obesity stands out as a direct and recognized risk factor. Recent travel history generally poses a risk in terms of exposure to new strains or outbreaks, and smoking history can exacerbate respiratory conditions; however, obesity's direct impact on immunity makes it a key area of concern for influenza-related complications.