This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cystic fibrosis & Sleep apnea, Subject name: Medicine
[{'content': 'What is the most common cause of obstructive sleep apnea? \nSelect and explain. \nA. Craniofacial abnormalities, B. Hypothyroidism, C. Alcoholism, D. Acromegaly', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Craniofacial abnormalities are common in O.S.A in non-obese patients and children. Non structural risk factors for OSA include: Obesity, central fat distribution Male sex, middle age Alcohol use, sedative use, smoking Supine sleep position', 'role': 'assistant'}]