Mouth Breathing, Snoring and Childhood Obstructive Sleep Apnea Syndrome (OSAS)

Dr. NG Kwok Keung, Daniel

Honorary Consultant in Paediatrics

Specialist in Paediatric Respiratory Medicine

My interest in paediatric respiratory medicine goes back to 1992 when I was appointed Senior Medical Officer. My boss asked me to take charge of the asthma clinic in Kwong Wah Hospital (KWH). Respiratory diseases are the commonest diseases in children. Amongst these, the commonest is undoubtedly allergic rhinitis. I noticed that a lot of these children got allergic shiner, snoring and symptoms of Attention Deficit Hyperactivity Disorder (ADHD). In 1999, I spoke with the Head of the Department of Medicine of HKU, my alma mater, Prof. SK LAM, about my desire to undertake a MD program focused on sleep disordered breathing (SDB). He was supportive and directed me to speak with Prof. Mary IP who had known me from my previous work in the field of paediatric SDB. She kindly endorsed my proposal and I became a MD student in HKU. It took me another 6 years before I obtained my MD from HKU in 2006. The 6 years were an exciting journey in my search for my knowledge in the emerging field of paediatric SDB. In the journey, I made many friends and discovered a few new things, amongst which is habitual snoring is very common, i.e. 10% of children in Hong Kong, and is associated with adverse impact on health.

Fast forward to 2019, the year I joined HKSH family. I was pleased to find that its sleep laboratory is the best-run private service in Hong Kong. This allows me to continue my pursuit in the management of OSAS. I am blessed to be able to continue research in collaboration with my colleagues in KWH and we published a paper last year showing that frequent mouth breathing during sleep is a risk factor for persistent OSAS after surgery. As a Specialist in Paediatric Respiratory Medicine, I have seen a lot of children mouth breathing, and when I ask them for symptoms of OSAS such as snoring, restless sleep, nocturia, ADHD, the answers are often positive. As the mandible will grow in the direction of the mouth position, I know that a lot of these mouth-breathing children would become OSAS teenagers and adults. That is why I always emphasise the adequate treatment of allergic rhinitis to ensure the nasal patency as well as training the orofacial muscles to keep the mouth closed except when speaking.

You may be interested to know that OSAS occurs in 4% of middle-aged men and 2% of middle-aged women. The number skyrockets to 60% for those over 60 years of age. The million- dollar-question is at what time point OSAS starts its genesis in an individual and whether intervention at the initial part of the genesis would prevent OSAS in the future. My suspicion is the genesis starts at the first thousand days, i.e. from conception through 2 years of age, as the size of the pharynx is determined during this time. Frequent mouth breathing is a red flag for possible OSAS in the future. I invite readers to do some research on this aspect and ask me or your doctor for details if interested. Meanwhile, if your bed partner snores habitually, please ask him/her to see a doctor for a sleep PSG. Early treatment of OSAS can prevent stroke, acute coronary syndrome and dementia. So beware of the 4^th high, i.e. high apnea index on top of the well-known “3 highs”, namely high cholesterol, high blood pressure and high blood sugar.  Early treatment of all the four highs would ensure a happy and healthy life.