ESR, or erythrocyte sedimentation rate, is influenced by various factors. It tends to increase in response to inflammation, infection, autoimmune diseases, certain cancers, and tissue damage. Additionally, factors such as pregnancy, advanced age, anemia, and certain medications (like oral contraceptives) can lead to a higher ESR. On the other hand, factors that decrease ESR include treatment of the underlying condition causing inflammation or infection, resolution of the inflammatory process, and certain medications like corticosteroids. It is important to note that ESR is a nonspecific marker, and further evaluation is necessary to identify the underlying cause of the elevation and monitor the response to treatment.