What is the fine-grained topic of the following text: In a study of 901 professional musicians, the woodwind players also had a lower risk of apnea than did singers or conductors, according to Christopher P. Ward, Ph.D., an assistant professor of psychiatry at the University of Houston-Clear Lake, who reported the findings at the meeting of the Associated Professional Sleep Societies here. Only return the topic.
The risk of apnea in professional musicians based on their roles.