Obstructive Sleep Apnoea (OSA) and Diabetes: A Summary

Author: Professor Ram Dhillon

An Apnoea is essentially a nocturnal strangulation, due to blockage of the upper breathing passages, for a minimum of 10 seconds, but could be more: 15, 20, 30, or 40+ seconds. If an individual has 5 or more of these episodes per hour during sleep, the disorder OSA is present. Mild OSA is 5-15 apnoeas per hour; Moderate OSA is 15-30 apnoeas per hour and severe is 30+ apnoeas per hour. This is called the AHI score/index and is a grading system of severity.

OSA is associated with obesity, diabetes (type 2), heart disease, and dementia, amongst many other disorders. These associations are due to the metabolic and physiological consequences of the strangulation/apnoea, and, in many individuals, the low blood oxygen levels that can accompany each episode.

OSA affects ~ 4-8% of the population. In the UK between 2.4-4.8 million, India: is mainly confined to the upper and middle classes with an estimated 35 million affected, and in the USA about 30 million. In the Middle East, Emirates, the local population risk is about 22% of the population. In China, the prevalence is about 12%, so 140 million affected, and generally the Chinese exhibit a lower BMI score.

Individuals with established OSA should be managed with proper medical assessment (a sleep study) and management, which would be lifestyle changes (which are hard to implement and maintain) but also consider interventions such as Mandibular Advancement Devices (MADs) and CPAP (Continuous Positive Airway Pressure).

Obstructive sleep apnoea (OSA) and diabetes are two prevalent health conditions that often coexist and have significant implications for public health. The correlation between these conditions has been a subject of extensive research, revealing complex interconnections that suggest a bidirectional relationship i.e. OSA leading to Diabetes and Diabetes leading to OSA.

Diabetes mellitus, particularly type 2 diabetes (T2D), is a metabolic disorder characterized by chronic hyperglycemia due to insulin resistance and relative insulin deficiency. It is a leading cause of morbidity and mortality worldwide, with an estimated global prevalence of 9.3% among adults aged 20-79 years. The primary risk factors for T2D include obesity, physical inactivity, poor diet, and genetic predisposition.

Numerous studies have highlighted the high prevalence of OSA among individuals with T2D. For instance, an observational study by Foster et al. (2009) found that 86% of obese individuals with T2D had OSA, with 30% having severe OSA. Similarly, a meta-analysis by Reichmuth et al. (2005) indicated that the presence of OSA increased the risk of developing T2D by 1.4 times compared to those without OSA.

Several mechanisms underpin the association between OSA and T2D. Intermittent hypoxia (low oxygen) and sleep fragmentation, hallmarks of OSA, contribute to metabolic dysregulation. Intermittent hypoxia induces oxidative stress and inflammation, which culminates in insulin resistance, so the individual is unable to reduce blood circulating sugar. Inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) are elevated in OSA patients, this further exacerbates insulin resistance and promotes the development of T2D.

Additionally, sleep disruption affects glucose metabolism by altering the autonomic nervous system balance, increasing sympathetic activity (the fight/flight response of the body), and reducing parasympathetic activity. This imbalance contributes further to insulin resistance and impaired glucose tolerance. OSA is associated with obesity, a critical risk factor for T2D, creating a vicious cycle where each condition exacerbates the other.

Understanding the interplay between OSA and diabetes is crucial for effective management. Treating OSA with continuous positive airway pressure (CPAP) therapy has been shown to improve insulin sensitivity and glycaemic (sugar) control in diabetic patients. For instance, a randomized controlled trial by Harsch et al. (2004) demonstrated significant improvements in insulin sensitivity in patients with T2D following CPAP treatment.

Conversely, managing diabetes can also positively impact OSA. Weight loss achieved through lifestyle modifications or bariatric surgery, has been shown to reduce the severity of OSA and improve metabolic parameters in diabetic patients.

The correlation between obstructive sleep apnoea and diabetes is well-documented in scientific literature, highlighting a bidirectional relationship driven by shared risk factors and pathophysiological mechanisms. Intermittent hypoxia, sleep disruption, and inflammation in OSA contribute to insulin resistance and the development of T2D. Conversely, managing diabetes through weight loss and lifestyle interventions can mitigate the severity of OSA. Addressing these interconnected conditions through comprehensive, multidisciplinary care is vital for improving patient outcomes and reducing the burden on healthcare systems. Future research should continue to explore the mechanisms linking OSA and diabetes and develop targeted interventions to break this detrimental cycle.

Some stark statistics

Individuals, over 65 years of age, are diagnosed with dementia. With an ageing population, this is expected to grow rapidly:
UK: 1 million
USA: 6.7 million
India: 8.8 million
Saudi Arabia: 1.8 million

WHO: worldwide ~55 million (2020) projected to rise to 78 million by 2030.

In the one-third of individuals with dementia who have OSA, the latter diagnosis and management will significantly enhance personal/family quality of life AND reduce the financial burden.

FINALLY: Do you have Sleep Apnoea? Use the attached “Modified STOP BANG” triage questionnaire.

LISTEN TO THIS PODCAST: The Hidden Dangers of Untreated Sleep Apnoea with Professor Ram Dhillon

For more information on Obstructive Sleep Apnoea and Snoring, visit ENT London.