Are there certain groups of people who suffer anemia more often?

Yes. The most common group is menstruating females. If their periods are excessive and/or they don't get enpugh iron in their diet anemia may result. There are certain familial and ethnic groups that are prone to unusual types of anemia, as well.
Fe deficiency anemia. Is the most common cause of anemia by far in the us. It favors two groups, but can happen to anyone whose needs exceed their fe intake. The first group is menstruating females, who have a monthly blood loss. The second group is infants/toddlers who either are breast fed without adequate fe supplementation or who have excessive cows milk intake which, which is fe poor & can cause occult blood loss.