Dental Management of Sleep Disorders. Ronald Attanasio

1 Impact of Sleep Disorders on Society

      Conceptual Overview

      Sleep disorders can no longer be thought of as simply having a poor night's sleep. At the current time, there are a large number of different sleep disorders that may affect one's quality of life (QOL). In addition, there is a difference between the sleep state and the wake state. Sleep is not simply an altered state of consciousness. In other words, it is not simply a matter of being asleep or being awake. Sleep is a totally separate behavioral and physiologic state that is unique and well documented. Carskadon and Dement define sleep in this way: “Sleep is a reversible behavioral state of perpetual disengagement from and unresponsiveness to the environment” [1]. As such sleep is a combination of rapid eye movement (REM) and non‐rapid eye movement (NREM) sleep associated with well defined and variable brain activity [2].

      Sleep disruption and the specifically recognized sleep disorder may have a major impact on one's well‐being, health status, and even QOL. There may also be other associated public health concerns that are related to accidents, mortality, morbidity, utilization of healthcare, executive function, and routine daily tasks. Therefore, as good sleep may have a positive impact on one's life, the presence of a sleep disorder may have the opposite effect.

      The Evolution of Sleep in Modern Times

      Sleep was not always as we know it today or have known it for over 100 years. Prior to the industrial revolution, sleep and wakefulness were mostly predicated by the rising and setting of the sun. When the industrial revolution occurred, the 24‐hour day was broken down into three 8‐hour periods: one for work, one for sleep, and the other one for pleasure and other activities. Prior to this time, sleep was typically broken down into two stages or shifts and was referred to as “segmented sleep” [3]. These were referred to as first and second sleep or alternatively as “dead sleep” and “morning sleep.” Between these two was a period referred to as “the watching,” which was a period of wakefulness that would last for an hour or even longer in some situations. Furthermore, the eight‐hour uninterrupted period of sleep became more common because of the use of supplemental light that resulted in bedtimes that became later and as such the period between the two stages eventually disappeared.

      As sleep became more like we know it today, as is explained in a book by Benjamin Reiss [4], the industrial age changed many things. Where people would sleep in a communal manner, they now would have separate bedrooms. More importantly, sleep disorders that we recognize today most likely were being recognized and became more prevalent.

Another example was Henry David Thoreau's Walden. This was produced when he decided to abandon the sleep pattern of the day and return to one from the past. This led to a time of creativity that had not previously been experienced.

      As time progressed, other changes in society were taking place that ultimately would impact our circadian clock and our sleep. One such change was in 1910 when standardized time zones were established, mainly because of the need for railroads to synchronize schedules. Today many changes related to modernization and technology are all in some way impacting our sleep.

      Epidemiology and Prevalence of Sleep Disorders

      The origin and onset of a specific sleep disorder is often multifactorial. Epidemiology as it applies here is the study of a particular sleep disorder and how it impacts the overall health of the patient. By definition, epidemiology is the study of the occurrence of a particular disorder and how it impacts the health as well as the diseases of different and varying populations [5]. It is basically the foundation for public health. A text specific to the study of epidemiology has defined the four major concerns associated with this [6].

      Specifically, clinical epidemiology applies to how the occurrence of a particular condition, in this case a sleep disorder, is related to the occurrence as well as the distribution of a disease and how this impacts other risk factors. The ultimate goal is the improvement in people's health. Currently, the most common sleep disorders based on epidemiologic studies are [7]:

      The ultimate outcome of these early epidemiologic studies of sleep resulted in the first published classification of sleep disorders that over time has been modified and revised. At the current time, the International Classification of Sleep Disorders, third edition, (ICSD‐3) is the evidence‐based standard for the diagnosis of sleep disorders [8].

      The general onset of sleep disorders as well as their progression is to some degree dependent on age, the presentation of being at risk for health‐related consequences, and even trauma. In many instances, these disorders may appear as a health issue as well as some type of emotional or psychological condition. In many instances, it is the presentation of the health problem that is first recognized or diagnosed that may have its origin as a sleep disorder. As an example sleep apnea patients may seek treatment and use more healthcare resources for the diagnosis of the cardiovascular disease (CVD) and more specifically hypertension prior to the diagnosis of the underlying cause, that being the sleep apnea [9].

      The prevalence of sleep disorders based on epidemiologic studies is most often cited as occurring in each of the specific one’s as opposed to a general statistic overall. Hence, the actual distribution of a specific sleep disorder is variable dependent on the study that is presented. As an example, it is best to consider the three most common sleep disorders as previously cited.

      Prevalence of Sleep Apnea

An example of the most often cited study on the prevalence of sleep apnea is from a 1993 study that was published in the New England Journal of Medicine [10]. In this study of 602 people, it was determined that 24% of men and 9% of women are at risk for sleep‐related breathing disorders (SRBDs). When this same group also had daytime hypersomnolence, the prevalence of sleep apnea was determined to be 4% of men and 2% of women. A more current study in 2013 found that there was an increase in prevalence of SRDB that ranged from 14 to 55% based on age, sex, and severity of the apnea hypopnea index (AHI) [11]. This study looked at age groups by their sex and found that in men the prevalence was 10% (age 30–49) and was 17% (age 40–70). In women, the prevalence was 3 and 9%, respectively for the same age groups. The prevalence in this case was based on an AHI of 15 or greater. When an AHI of 5 or more was considered, in ages 30–70, along with daytime sleepiness, the prevalence was determined to be 14% in men and 5% in women.

      Since 2013, there have been other studies that have determined the prevalence of SRDB. The facts from two other studies that are significant merit consideration.