Chronic Disease: Conditions like chronic kidney disease, liver disease, or chronic infections can lead to folic acid deficiency due to increased demand, decreased absorption, or impaired utilization. The elevated ESR suggests an underlying inflammatory process, which is common in chronic diseases.

Malabsorption: Conditions such as celiac disease, Crohn's disease, or ulcerative colitis can cause malabsorption of folic acid, leading to deficiency. The elevated ESR may indicate active inflammation in these diseases.
Medication-Induced: Certain medications like methotrexate, phenytoin, or sulfasalazine can interfere with folic acid metabolism or absorption, leading to deficiency. The elevated ESR may be related to the underlying condition being treated or a side effect of the medication.
Pregnancy: Pregnancy increases the demand for folic acid, and deficiency can occur if dietary intake is inadequate. The elevated ESR can be seen in normal pregnancy due to increased fibrinogen levels.

Malignancy: Certain cancers, such as leukemia or lymphoma, can cause folic acid deficiency due to increased cell turnover and demand. The elevated ESR is a nonspecific marker of inflammation that can be seen in malignancy.
Inflammatory Bowel Disease: Conditions like Crohn's disease or ulcerative colitis can cause folic acid deficiency and have an elevated ESR due to chronic inflammation.
Sepsis: Severe infections can lead to folic acid deficiency due to increased demand and impaired utilization. The elevated ESR is a marker of the systemic inflammatory response.

Orotic Aciduria: A rare genetic disorder that affects pyrimidine synthesis, leading to folic acid deficiency. The elevated ESR may be related to the underlying metabolic disorder.
Congenital Disorders of Folate Transport: Rare genetic conditions that impair the transport of folic acid, leading to deficiency. The elevated ESR may be related to the underlying condition or secondary complications.