Which symptom is associated with Type 1 diabetes mellitus?

Polydipsia, or excessive thirst, is a classic symptom associated with Type 1 diabetes mellitus. This condition arises due to the inability of the body to produce insulin, leading to high blood sugar levels. As glucose accumulates in the bloodstream, the kidneys work to eliminate the excess glucose through urine, resulting in increased urination (polyuria). As a consequence of fluid loss, the body becomes dehydrated, prompting an increased sensation of thirst, or polydipsia.

In contrast, obesity is more commonly associated with Type 2 diabetes rather than Type 1, which often develops in younger individuals who may be of normal weight or even underweight. Increased energy is not a symptom of diabetes; rather, individuals often experience fatigue due to the body’s inability to utilize glucose for energy effectively. Similarly, a normal appetite is not indicative of diabetes; people may experience increased appetite but do not get the nutrients they need due to the body's insulin deficiency. Thus, polydipsia is the most relevant and predictive symptom for Type 1 diabetes mellitus.