Obstructive Sleep Apnea Syndrome and Hypothyroidism—Merely Concurrence or Causal Association?

Abstract

The prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) ranges from 4 to 7% in men and from 2 to 5% in women. Its deleterious consequences such as traffic accidents, cardiovascular complications increasing morbidity and mortality, make it a major health problem. Apart from obesity (a major risk factor for OSAHS), hypothyroid patients are prone to reveal this phenotype. Although hypothyroidism seems an acknowledged risk factor for OSAHS, some authors report the lack of clinically relevant association. The argument partly depends on the increased prevalence of hypothyroidism in OSAHS patients, but the epidemiological data is limited and somehow inconsistent; even less is known about sub-clinical hypothyroidism in OSAHS patients. Even if frequency of overt and sub-clinical hypothyroidism in OSAHS patients is comparable to the general population, screening for it seems beneficial, as hormone replacement therapy may improve sleep disordered breathing. Unfortunately, this favorable outcome was found only in a few studies with limited number of patients with hypothyroidism. Yet, despite the lack of international guidelines and no large multicentre studies on the topic available, we think that TSH screening might prove beneficial in vast majority of OSAHS patients. Obstructive sleep apnea-hypopnea syndromeObstructive sleep apnea -hypopnea syndrome (OSAHS) is a chronic condition, characterized by recurrent pauses in breathing during sleep. In consequence, they lead to sleep fragmentation and intermittent hypoxemia. Decreased quality of sleep leads to excessive day time sleepiness, cognitive dysfunction and impaired work performance [1]. OSAHS contributes to systemic hypertension [2], cardiovascular diseases [3] and abnormalities in glucose metabolism [4]. The reported prevalence of OSAHS in adult population ranges from 4 to 7% in men, and from 2 to 5% in women [1,5]; with some subgroups of the population bearing higher risk [1]. It is a serious health problem considering high prevalence and its deleterious consequences, e.g. traffic accidents or all causes related morbidity and mortality [6−8]. Polysomnography is an acknowledged gold standard in OSAHS diagnostics. Clinical and sub-clinical hypothyroidismPrimary hypothyroidism is a condition, in which thyroxin levels in blood are reduced and are accompanied by increased levels of TSH as an effect of disruption of negative feedback mechanism. Thus, hypothyroidism is diagnosed when concentration of serum TSH exceeds 4.5 mIU/L and free T4 (FT4) concentration is below the reference range: 0.8−2.0 ng/dL (10.3−25.7 pmol/L). The reported prevalence of overt hypothyroidism

Association between obstructive sleep apnea and comorbidities with periodontal disease in adults

“…Hypothyroidism was also statistically associated with periodontitis and mild sleep apnea. Previous studies have been reported the association between OSA and hypothyroidism [ 35 36 ] and between hypothyroidism and periodontitis;[ 37 38 ] however, the physiopathology of these interrelationships has not been established and the association between hypothyroidism, periodontitis, and sleep apnea has not been previously documented. Diabetes mellitus was frequently observed in patients with OSA, but this association was not statistically significant.…”

A Narrative Review of Cerebellar Malfunctions and Sleep Disturbances

“…Glutamate is also an important neurotransmitter, which acts as a stimulant for brain activity. Thus, the abnormal ratio of GABA to glutamate may adversely affect the regulation of the sleepwake cycle (Kuczyński et al, 2016). OSA has been associated with sympathetic activation, excessive daytime sleepiness, and cognitive function changes.…”

Influence of innate immune activation on endocrine and metabolic pathways in infancy

“…Similarly, an older study reported that severe hypothyroidism is associated with depressed ventilatory drive during hypoxic and hypercapnic respiration (161). Adults with hypothyroidism often suffer from disordered breathing (162). However, in patients with obstructive sleep apnea, low thyroid hormones is not a common comorbidity (162,163).…”