A 35-year-old woman from rural India presents with fatigue and dyspnea on exertion. Blood investigations show hemoglobin 8.5 g/dL with microcytic hypochromic indices. Serum ferritin is low and TIBC is elevated. What is the most common cause of anemia worldwide?

Explanation

## Most Common Cause of Anemia Globally **Key Point:** Iron deficiency anemia (IDA) is the most common cause of anemia worldwide, affecting approximately 1.6 billion people globally, with particularly high prevalence in developing countries like India. ### Epidemiology - **Prevalence:** ~30% of world population has anemia; IDA accounts for ~50% of all anemia cases - **High-risk groups:** Women of reproductive age, children, pregnant women, and populations with poor dietary iron intake - **Geographic distribution:** Highest in South Asia, Sub-Saharan Africa, and Southeast Asia ### Why IDA is Most Common | Factor | Impact | |--------|--------| | **Dietary inadequacy** | Low bioavailable iron in vegetarian diets common in India | | **Blood loss** | Menstrual losses in women; GI bleeding (hookworm, peptic ulcer) | | **Malabsorption** | Celiac disease, H. pylori infection | | **Pregnancy/lactation** | Increased iron demands | **Clinical Pearl:** The microcytic hypochromic pattern with low ferritin and elevated TIBC in this patient is pathognomonic for iron deficiency. **High-Yield:** In India, the most common causes of IDA are: 1. Nutritional deficiency (vegetarian diet, poverty) 2. Menstrual blood loss (women) 3. Parasitic infestation (hookworm, roundworm) 4. GI bleeding ### Laboratory Findings in IDA - Hemoglobin: <12 g/dL (women), <13.5 g/dL (men) - MCV: <80 fL (microcytic) - Serum ferritin: <15 ng/mL - TIBC: >360 μg/dL (elevated) - Serum iron: <60 μg/dL - Transferrin saturation: <16%