Anemia is lack of RBC in body or disfunctional RBCs. Risk factors would be things that make you prone to have this disease. Some commonly known factors are:
Menstruation
Pregnancy
Age (more common as you keep aging)
Chronic conditions
Family history (genetics does make you less or more prone)
Many more!
For more info visit: https://www.mayoclinic.org/diseases-conditions/anemia/symptoms-causes/syc-20351360
