There are more reasons for calcium deficiency, including insufficient calcium intake, physical inactivity or metabolic diseases. 1. Insufficient calcium intake: If you do not have a balanced diet in your daily life and are picky about your tastes. If you don’t eat a lot of food, resulting in an unbalanced intake of nutrients, it will lead to calcium deficiency or malnutrition over time. 2. Do not like sports: if you do not like to do some outdoor sports, rarely active, will lead to the body of vitamin D synthesis is insufficient, thus calcium absorption or calcium deficiency. 3. Metabolic diseases: If you suffer from hypoparathyroidism and other diseases that can lead to abnormal calcium metabolism, it will affect calcium metabolism, thus calcium deficiency will occur. If you have a calcium deficiency, you should consult a doctor in a timely manner to identify the cause of the disease and carry out targeted treatment.