What is the fine-grained topic of the following text: It's a good thing to see our celebrity youths assuming positions like these especially as sickle cell is one of the biggest killers in the black community.Nigeria in particular have the highest number of sickle cell sufferers in the world by the virtue of being the most populous black nation on earth. Only return the topic.
Celebrity involvement in sickle cell awareness in the black community and Nigeria's high rate of the disease.