Review
Copyright ©The Author(s) 2016.
World J Gastroenterol. Sep 21, 2016; 22(35): 7908-7925
Published online Sep 21, 2016. doi: 10.3748/wjg.v22.i35.7908
Table 1 Overview of diseases considered to be associated with iron deficiency/iron deficiency anemia
ConditionsAnemia or IDA prevalencePredominant pathological contributors to anemia
Association with anemia and ID
BleedingMalabsorptionInflammation
Nonvariceal upper GI bleeding[33]80%> 80% of patients admitted to hospital with nonvariceal AUGIB were anemic at the time of discharge
Celiac disease[87-89]32%-69%Well-established relationship between celiac disease and IDA
Most widely cited cause of IDA is abnormal iron absorption, but bleeding and inflammation are also known contributory factors
Intestinal parasitic infections[151]33%-61%T. trichiura and hookworm infections are closely associated with IDA
GI cancers[107,108,111,117,121-120]50%-60%CRC: IDA associated with greater tumor diameter and with cancers of the right side of the colon
Polyps: IDA much more common with malignant polyps than benign polyps
GIST: Most frequent presentation is GI bleeding, which can result in anemia. In pediatric GIST, anemia is the most frequent clinical finding
Gastric cancers: 6.8-fold relative risk of gastric cancer in patients with Pernicious anemia
Small bowel malignancies: Anemia among most common presenting symptoms
Esophageal cancers: Patients with Fanconi anemia at increased risk
Esophagitis and hiatal hernia[23-26]8%-42%Gastric bleeding from hernia is an established cause of IDA
Even in absence of visible lesions, large hernia may be a possible cause of IDA with unexplained etiology
Bariatric surgery[77,196]10%-40%ID and anemia are well-known risks after bariatric procedures, but causes are multifactorial and vary depending on exact procedure and patient population
Intestinal failure[101-103]30%-37%Intestinal failure is associated with ID due to malabsorption, GI blood loss, and multiple surgery
Diverticular disease[144]25%One of the most common causes of lower GI bleeding leading to IDA
Increasing prevalence due to rise in elderly population
Restorative proctocolectomy[153]6%-21%IDA due to mucosal bleeding and impaired iron absorption in patients developing symptomatic or asymptomatic pouchitis
NSAID-associated fecal blood loss[1]10%-15%Even low dose aspirin and non-aspirin-NSAIDs increase mean fecal blood loss 2-4-fold compared with normal
Angiodysplasia[1]5%Most common cause of lower GI bleeding in the elderly
Gastric antral vascular ectasia (GAVE)[1,48,55]1%-2%Chronic, slow bleeding is typically associated with IDA
Gastritis[57,66]NAH. pylori infection suggested to play important role in development of IDA
Peptic ulcer[197]NAH. pylori infection and IDA as above. Additionally, bleeding from ulcer
Chronic hepatitis and liver conditions with GI bleeding[155]75%Chronic liver disease can be complicated by anemia, particularly due to bleeding
Non-alcoholic fatty liver disease (NAFLD)[171]NAOne-third of adult NAFLD subjects are reported to be iron deficient, defined by a TSAT < 20%
Table 2 Estimated total iron deficit (mg elemental iron) based on hemoglobin and body weight
Degree of iron deficiencyHemoglobin level (g/dL)Iron deficit (mg)
Body weightBody weight
< 70 kg 70 kg
Moderate10-12 (women)10001500
10-13 (men)
Severe7-1015002000
Critical< 720002500