Which medical condition is not directly linked to worsening severity of periodontal disease?

Asthma is the condition that is not directly linked to worsening the severity of periodontal disease. While it is important to recognize that chronic conditions can have varied effects on oral health, asthma does not have a significant direct association with periodontal disease compared to the other options.

Diabetes is known to greatly influence periodontal health; high blood sugar levels can impair healing and increase the risk of infections, including those of the gums. Stress can lead to behaviors such as teeth grinding and reduced oral hygiene, which can worsen periodontal disease. Vitamin C deficiency is also significant; it can lead to scurvy, characterized by gum disease, and increased susceptibility to infections. Each of these conditions directly impacts oral health through various physiological mechanisms, making them more closely linked to periodontal disease severity.