Too much or too little iron in the system can be fatal. Death is often due to heart or liver failure.

Risk Factors* for too much or too little iron
*A risk factor is any behavior, condition or environmental factor known to increase the possibility of a disease outcome.  

Risk factors for too much iron include but may not be limited to:

• Taking excessive amounts of supplemental iron; or receiving iron shots or iron infusions
• Having received (or are receiving) frequent blood transfusions
• Consuming excessive amounts of red meat or foods that enhance iron absorption (supplemental vitamin C, alcohol, sugar)
• Having risk factors for metabolic syndrome that heighten the risk of type 2 diabetes and cardiovascular diseases
• Using tobacco products on a regular basis or being exposed to tobacco smoke (lung)
• Being exposed to iron-containing asbestos (lung)
• Working or long-term computing in subways (lung)
• Working in iron smelters or coal mines (lung)
• Living in highly polluted areas—usually large metro-urban cities (lung)
• Having an inherited iron loading condition such as hemochromatosis

Risk factors for too little iron include but may not be limited to:

• Age and gender: women, children and the elderly are most at risk
• Ethnicity: non-whites are at increased risk
• Consuming foods or substances that impair iron absorption: fiber, tannin in coffee or tea, dairy products, eggs, or chocolate
• Being a super blood donor (especially people with hemochromatosis who are overbled)
• Having inherited conditions that impair absorption: celiac’s, crohn’s—colitis
• An inadequate intake of iron (not enough meat or being strictly vegetarian)
• Excessive aerobic exercise, marathon runner
• Taking aspirin, antacids or calcium supplements
• Being exposed to toxins (chemicals) such as lead,
• Abusing drugs: pain meds, alcohol
• Diseases  of the digestive tract; infection; diseases of the endocrine system or bone marrow
• Surgery, gastro banding or short bowel syndrome
• Having an eating disorder (bulimia)
• Having an inherited anemia such as thalassemia or sickle cell disease

Complicated Iron (many of these are rare): when you have too much and too little at the same time

• Anemia in these patients is due to having a particular disease of blood cell production or blood cell management such as thalassemia, sickle cell disease, sideroblastic anemia, enzyme deficiencies, bone marrow problems, iron-transport protein  problems.  Iron overload is often caused by a combination of the disease itself and the treatment, which is often blood transfusion or iron infusion.