Overview of sleep and sleep medicine in Asian countries


Dr Yoan Cherasse, Department of Molecular Behavioral Biology, Osaka Bioscience Institute, Suita, Osaka 565-0874, Japan. Email: cherasse@obi.or.jp


While there are a number of sleep medicine and sleep research publications in Asia, and their quality is increasing each year, the actual situation of sleep disorders in the general population still remains an issue of major concern. Scientists and medical doctors believe that, for the first time in history, the general lack of sleep could lead to a diminution of life expectancy. It is also known that, as people are working more and more and are more tired, they are more likely to become victims of accidents. Most of the time these incidents have little gravity, but sometimes they can cost thousands of innocent lives or contribute to disasters such as the Chernobyl nuclear plant explosion or the Bhopal gas tragedy. Based on the Asian Sleep Research Society Summit and Symposium Round Table held during the fall of 2009 on Okinawa, this review aims to give an accurate view of the actual situation of sleep research and medicine in Asia. The particular example of the obstructive sleep apnea syndrome will illustrate the importance of sleep medicine in this part of the world. Finally, the actual situation will be discussed to elaborate some possible strategies to improve the sleep situation for Asian populations.

There is an increasing concern about sleep disorders everywhere in the world. Only a few studies are available that have evaluated the change in the amount of sleep during recent decades, but all of them conclude that a diminution of sleep duration is occurring in our modern societies. Surveys in some countries have demonstrated a mild reduction in the resting period, such as the loss of 18 min in Finland during the last 33 years.1 But it is even worse in many other countries, such as Japan, where there has been about 40 min lost during the last 40 years, and is more critical again in countries such as the USA (more than 1 h lost since the 1960s).2 In parallel with this reduction in sleep amount, these same countries have reported a rapid and serious increase in sleep disorders and other related diseases. Today, more than 30% of the human population suffer periodically or constantly from one of the 107 sleep diseases identified so far.

With 4 billion inhabitants, Asia is the most populated region in the world, housing about 60% of the entire population of the planet. It appeared very early to the medical communities in these countries that sleep disorders were increasing; and to counteract this progression, many doctors and researchers created national sleep societies during the 1980s and early 1990s. Over the years, they founded many ambitious projects and finally, in 1994, created the Asian Sleep Research Society (ASRS) under the leadership of Professor Shojiro Inoue from the Japanese Society of Sleep Research (JSSR). Nowadays, the ASRS embraces sleep societies from 13 Asian countries (China, Hong Kong, India, Indonesia, Israel, Japan, Korea, Malaysia, Pakistan, Singapore, Taiwan, Thailand, and Turkey) and comprises more than 3500 members, and has thus become the second largest sleep society in the world.

In this review we will analyze the situation of sleep and sleep medicine in Asian countries and the actual situation of their respective sleep societies based on the ASRS Summit and Symposium round table held in 2009 (Table 1). We will particularly focus on the example of a sleep-related disease referred to as the obstructive sleep apnea syndrome (OSAS). Some solutions to solve encountered issues and to improve the general sleep deprivation situation will then be discussed before explaining how essential is the work being done by sleep doctors and sleep societies for current populations and future generations.

Table 1.  List of speakers at the ASRS Summit and Symposium round table held in 2009 in Okinawa, Japan, and their respective sleep societies
SpeakerSocietySociety website
Dr. Ken-ichi HonmaAsian Sleep Research Societyhttp://www.asrsonline.org/
Dr. Fang HanChinese Sleep Research Societyhttp://www.csrs.org.cn/
Dr. Kah Lin ChooHong Kong Society of Sleep Medicinehttp://www.hkssm.org/main.php
Dr. Yun-Kwok WingHong Kong Society of Sleep Medicinehttp://www.hkssm.org/main.php
Dr. Nanda Hruda MallickIndian Society for Sleep Researchhttp://www.issr.in/president.asp
Dr. Bindu M. KuttyIndian Society for Sleep Researchhttp://www.issr.in/president.asp
Dr. Tetsui ShimizuJapanese Society of Sleep Researchhttp://www.jssr.jp/
Dr. Do-Un JeongKorean Academy of Sleep Medicinehttp://www.sleep.or.kr/
Dr. Leen KimKorean Academy of Sleep Medicinehttp://www.sleep.or.kr/
Dr. Chul Hee LeeKorean Society of Sleep Medicinehttp://www.sleep.or.kr/
Dr. Baharudin AbdullahSleep Disorders Society Malaysia 
Dr. Hang Liang-wenTaiwan Society of Sleep Medicinehttp://www.tssm.org.tw/news.php
Dr. Murat ÖzgörenTurkish Sleep Study Group 
Dr. David Russell HillmanAustralian Sleep Associationhttp://www.sleepaus.on.net/


It is a very difficult task to give a clear view of sleep diseases and the situation of sleep medicine in Asia. This is the largest and the most populous region in the world, covering a countless number of ethnic groups. Furthermore, even though there have been only a few studies analyzing sleep and sleep disorders in Asia, all recent sleep studies have led to the same conclusion: people are not only sleeping less, but also the quality of their sleep is getting worse. A global survey from ACNielsen in 2004 demonstrated that 41% of Japanese are sleeping less than 7 h a day while 12% of Indonesians are sleeping less than 6 h. With 60% of Japanese people going to bed after midnight and 64% getting up before 7:00 am, they concluded that the Japanese are the most sleep-deprived people in Asia.3

This reduction in sleep time is also aggravated by the decline of its quality. Many sleep disorders are progressively increasing such as insomnia, which affects more than 20% of the Japanese population,4 and obstructive sleep apnea syndrome (OSAS). OSAS is a disorder characterized by the obstruction of the upper airway that occurs during sleep. The reduced ventilation causes repetitive episodes of hypoxemia and increased arterial PCO2, resulting in frequent awakening during the night and subsequent daytime sleepiness. Different studies measuring OSAS coupled to an Apnea–Hypopnea Index (AHI) higher than 5 and extreme daytime sleepiness in different countries of Asia have given scattered results because of differences in methodology, but all of them have concluded that, relatively speaking, the prevalence of OSAS is high compared with that in countries in other parts of the world. While this disorder affects 4.5% of men and 3.2% of women in Korea,5 and 4.1% of Chinese men in Hong Kong,6 which are results close to the ones observed for the USA (4% of men and 2% of women),7 it appears to be rather worse in other countries. Thus, in India OSAS with AHI >5 affects up to 7.5% of middle-aged urban men,8 and prevalence even reaches 8.8% for men and 5.1% for women in Malaysia,9 twice the usual Asian results!

We know that several factors can influence the prevalence of severe OSAS: some of them are natural ones such as ageing7,10 and gender11,12 or environmental factors such as altitude.13 Some Asian people also present an atypical craniofacial structure known to induce OSAS in Caucasians,14 especially in Malay subjects,15 which atypia may explain the comparatively higher prevalence in them than in other countries.

The increase in obesity (body mass index [BMI]≥30 kg/m2) in our modern societies is also one of the main factors contributing to the development of OSAS.11 Although obesity is well developed and can be considered as a major factor for the high prevalence of OSAS with AHI >5 in the USA, the situation in Asia is different. According to the World Health Organization (WHO), current obesity in China or Japan is under 5% of the adult population; and the mean BMI of global Asian countries is 22–23 kg/m2, compared with the 25–27 kg/m2 observed in North America and Europe.16,17 But the situation is changing rapidly, as the obesity rate is increasing constantly; and thus we can expect to observe a higher OSAS prevalence in the sensitive Asian population during the next few decades.

OSAS not only negatively impacts a person by increasing sleep apnea and daytime sleepiness, but some recent studies have revealed that it can also lead to serious health issues by increasing the risk of pulmonary hypertension,18 diabetes,19 and heart failure20 and can even induce sudden infant death syndrome.21 In China, the first patient with sleep apnea was diagnosed in 1981 in Peking Union Hospital, but unfortunately did not receive any treatment and died a few years later. From this experience it became apparent that it was necessary to develop a way to help patients suffering from OSAS. The current treatment consists of upper-airway surgery or the use of a non-invasive method with a continuous positive air pressure (CPAP) machine. These CPAP machines stop OSAS by blowing air at a prescribed pressure into the nasal cavity or into a full face mask, either one reducing drastically the upper airway obstruction. The new CPAP models designed and made in China since 1995 are much cheaper than those previously available on the Asian market, and this reduction in price can permit an exponential increase in the use of this non-invasive method. Today, more than 10 000 CPAP machines are sold every year in China. But the situation is still far from acceptable, essentially because the purchasing price of the equipment remains high in the Asian region, which includes some of the poorest countries in the world.

The actual situation regarding OSAS in Asia is quite representative of sleep diseases and sleep medicine in the world; that is, it is still in the development stage. Sleep disorders have been known for ages and treated by traditional herbs, exercises, acupuncture (China), yoga (India) or even music (Turkey) in the ancient traditional medicines. The 20th century has been marked by a deep modification of earlier lifestyles, with the advent of television and the internet, the development of a 24/7 society, and increases in shift-work and overtime work to increase productivity and to earn more money. Finally, on top of that an important reduction in sleep amount has been observed everywhere in the world. The situation is even worse for children,22 especially Asian children.23 The sleep of children is a primordial activity and has been demonstrated to be associated with memory and learning processing24 and with growth25 and to influence the expression pattern of many essential hormones.26 It is commonly admitted that elementary school-aged children must sleep for 10–12 h per day and that this amount decreases to 8–9 h per night for the older ones. However, Hong Kong Chinese adolescents have been reported to sleep 7.3 h per night;27 and Japanese high school students, 6.3 h per night.28 Korean kids are comparatively the ones with the shortest night's sleep in the world.29 This situation can lead not only to reduced academic performance, but also to poor impulse control, risk-taking behavior, impaired social functioning, and increased risk of injury.30

Aware of this worsening situation, some doctors decided to create national sleep societies in order to warn populations and healthcare professionals about this increasing societal problem. Thus, the first sleep society formed in Asia was the Japanese Society for Sleep Research (JSRS), established in 1977. The rapid success of this society has been the starting point of sleep science and sleep medicine in Asia. In China, the publication of five cases of sleep apnea in 1985 in the Chinese Journal of Internal Medicine31 led to the official recognition of OSAS as a syndrome by the Chinese medical community and to the creation of the Chinese Sleep Research Society (CSRS) in 1989. In the ensuing years, several other Asian countries created their own sleep societies (Korea, India, Hong Kong, Taiwan, Malaysia, etc.) and became federated as the Asian Sleep Research Society (ASRS) in 1994. The ASRS now represents 14 member societies from 13 countries and a total of more than 6500 affiliates, making it the second-biggest sleep society in the world. But there are still many countries in Asia that are not members of the ASRS; and, more problematic, most of them do not even have a domestic sleep society. It is therefore very difficult to inform the population and medical staff living in these countries about sleep disorders and how to recognize them. The communication also appears to be difficult even within some countries who are members of the ASRS. Great efforts have been made to improve the knowledge and the skills of sleep doctors and technicians. For example, the Hong Kong Society of Sleep Medicine (HKSSM) is organizing service training for sleep technicians, scientific meetings for sleep doctors and researchers, and educational courses, workshops, and symposia, resulting in the accreditation of more than 40 polysomnographic technologists during the last few years. The Taiwan Society of Sleep Medicine (TSSM) is also very active and has already developed qualification processes for technicians (in 2006) and sleep laboratories (in 2007), and is currently working on qualifying sleep specialists.

Despite all these efforts, the situation is still critical; and the demand for sleep-medical services is still very high. The number of sleep centers is dramatically low in some countries. About 60 sleep centers have been founded in India for a population of 1.18 billion people. In Hong Kong, it is not rare to have to wait for 1 year to be supported by a public hospital for sleep disorders; and patients must wait another 3 to 12 months to have their first polysomnography (PSG). The training for sleep doctors is another major problem. It is still problematic that the analysis of the same polysomnogram can lead to different conclusions depending on the sleep center and the training of the doctors. In Japan, as in many other countries in the world, sleep apnea is mainly treated by pulmonologists; whereas insomnia is treated by psychiatrists. But the basics of sleep disorders are sometimes not well understood by these doctors, since only a few of them are sleep specialists.


In the vast majority of cases, the populations of Asian countries are not aware of sleep problems, even when they are occurring to themselves. Because of the lack of large-scale national surveys, the global situation remains unclear. One idea to improve it would be the creation of national sleep research institutes in every Asian country. These institutes could federate not only scientists, clinicians, and technologists, but also people from other fields related directly or indirectly to sleep disorders, with the consequence hopefully being improved national coordination and international cooperation. These national sleep institutes could become the official authority delivering sleep training for sleep technologists and accreditations for sleep laboratories. That would insure standardization in sleep specialist training and lead to their higher qualification and finally contribute to better treatments for the patients. Another important function of such institutes would be to introduce and to promote sleep science to undergraduate students of medical school to make them better aware of this field and to help sleep to become a real medicine specialty as soon as possible in Asian countries.

The situation in some Pacific countries could be a good example. In Australia, a country also suffering from ageing, sleep medicine is taken seriously and is highly developed. Australian mass media are very interested in reporting the effects of sleep disorders on safety and their economic cost. Sleep is even an official medical specialty that requires several years of training to ensure the highest qualification. All of this forced the government to recognize sleep disorders as a real concern and to make some important decisions regarding them. Nowadays in Australia CPAP machines are partially funded at about 85% of the total price (depending on the state where people live) by the governmental basic healthcare. This was possible since the Australian government understood the societal price of bad sleep and sleep diseases. A study estimated the financial cost of sleep disorders in Australia for 2004 to be an overall 4.5 billion US dollars, which represents 0.8% of the Australian gross domestic product (GDP)!32 Such results can also be extended to other Asian countries. A previous study concluded that the cost related to poor sleep quality is extremely high in Japan;33 and as we are unaware of any study that has tried to estimate the economic cost of sleep disorders in Asian countries, we can hypothesize that it would be much higher than in Australia considering the difference in sleep quality between these countries. Such analyses could be the starting point to attract mass media interest and to facilitate the flow of information about sleep disorders to the general population and to their government.

Taken together, these data show that sleep research and sleep medicine in Asia are still in their infancy. While everybody agrees with the common saying that increasing sleep is a good way to improve the quality of life for people, statistics show clearly that the actual situation is getting worse every year. Fortunately, sleep doctors and scientists realized 30 years ago that something must and can be done to improve this situation. The first step was the creation of the national sleep societies. The next one must be the creation of national sleep centers. But to achieve this goal, sleep technicians will need the help and support of their governments. Reducing SD could be a way to reduce governmental deficits by diminishing economic loss related to SD (almost 1% of GDP), but it could also be a way to reduce pollution and global warming, that is by diminishing human activities and energy overconsumption. Last, but not least, such centers could provide an easier way to improve the quality of life and life expectancy of the citizenry.


This work was supported by grants from the Japan Society for the Promotion of Science (JSPS), the Program for the Promotion of Basic and Applied Researches for Innovations in Bio-oriented Industry and the Takeda Science Foundation.


The author indicated no potential conflict of interests.