Relationship between obstructive sleep apnea syndrome and thyroid diseases

Sex and Sleep Disruption as Contributing Factors in Alzheimer's Disease

Alzheimer's disease (AD) affects more women than men, with women throughout the menopausal transition potentially being the most under researched and at-risk group. Sleep disruptions, which are an established risk factor for AD, increase in prevalence with normal aging and are exacerbated in women during menopause. Sex differences showing more disrupted sleep patterns and increased AD pathology in women and female animal models have been established in literature, with much emphasis placed on loss of circulating gonadal hormones with age. Interestingly, increases in gonadotropins such as follicle stimulating hormone are emerging to be a major contributor to AD pathogenesis and may also play a role in sleep disruption, perhaps in combination with other lesser studied hormones. Several sleep influencing regions of the brain appear to be affected early in AD progression and some may exhibit sexual dimorphisms that may contribute to increased sleep disruptions in women with age. Additionally, some of the most common sleep disorders, as well as multiple health conditions that impair sleep quality, are more prevalent and more severe in women. These conditions are often comorbid with AD and have bi-directional relationships that contribute synergistically to cognitive decline and neuropathology. The association during aging of increased sleep disruption and sleep disorders, dramatic hormonal changes during and after menopause, and increased AD pathology may be interacting and contributing factors that lead to the increased number of women living with AD.

Evaluation of thyroid functions and obesity in obstructive sleep apnea syndrome

OBJECTIVE

Obstructive sleep apnea syndrome is associated with many chronic diseases.

METHODS

Obesity and thyroid function tests were evaluated retrospectively and cross-sectionally for 782 obstructive sleep apnea syndrome patients.

RESULTS

The mean patient age was 49.3±11.5 years, and the majority were obese (67.9%) or overweight (26.6%). The mean age of the patients in Group 2 (moderate/severe obstructive sleep apnea syndrome) was higher than that of Group 1 (simple snoring/mild obstructive sleep apnea syndrome). The rate of severe obstructive sleep apnea syndrome among obese patients (35.2%) was significantly higher than that of normal-weight (11.6%) and overweight (18.3%) patients (p=0.001). The oxygen desaturation index/apnea-hypopnea index and levels of leukocytes and C-reactive protein were significantly higher, while mean/minimum saturation values and hemoglobin, hematocrit, and free triiodothyronine levels were significantly lower among obese patients compared with overweight and normal-weight patients (p=0.001). Leukocytes, C-reactive protein, and apnea-hypopnea index/oxygen desaturation index values were higher, and mean/minimum saturation values were lower in Group 2 than in Group 1.

CONCLUSION

There were relationships between obstructive sleep apnea syndrome severity and body mass index. Obesity could be a critical predisposing factor for sleep disturbances. The prevention and control of obesity is important while being treated for obstructive sleep apnea syndrome.

Epworth sleepiness scale is associated with hypothyroidism in male patients with obstructive sleep apnea

BACKGROUND

Hypothyroidism could cause obstructive sleep apnea (OSA), however, the specific association of them remained unclear. This cross-sectional study aimed to determine the prevalence of hypothyroidism among patients with OSA, and the characteristics and predictors of hypothyroidism associated with OSA.

METHODS

A total of 573 patients with OSA were included in the study. Serum levels of thyroid stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) were measured in all participants. Univariate and binary logistic regression analysis were performed to assess the association of OSA with hypothyroidism while controlling for potential confounders. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the OSA effect in the distinction between euthyroid and hypothyroidism.

RESULTS

The prevalence of hypothyroidism was 6.75%、5.12%、10.38% in the total, men, and women cohort, respectively, and the prevalence rate in women OSA patients was significantly higher than that in men OSA patients (P=0.018). The men OSA patients with hypothyroidism had a higher Epworth sleepiness scale (ESS) than women OSA patients with hypothyroidism (P=0.022). Additionally, the ESS was significantly higher in men OSA patients with hypothyroidism than those with euthyroid (P=0.042), while women OSA patients had no such difference (P=0.822). In men patients with OSA, ROC curve analyses revealed that the risk of hypothyroidism increased in accordance with increasing ESS after adjustment for potential confounders, and the optimal cutoff value was 10 score. Higher ESS category was significantly associated with a higher risk of prevalent hypothyroidism in men patients with OSA [odds ratio (OR) = 4.898 for ESS≥10 relative to ESS <10, 95% confidence interval (CI) 1.628-14.731, P = 0.005].

CONCLUSIONS

The prevalence of hypothyroidism in OSA patients was relatively higher, especially in women OSA patients. ESS was significantly and positively associated with hypothyroidism in men patients with OSA, suggesting that ESS may have a potential role in identification and diagnosis of men OSA patients complicated with hypothyroidism.

Thyroid Dysfunction and Sleep Disorders

Thyroid disorders and sleep disorders are common problems in the general population that can affect people of all ages, backgrounds, and sexes, but little is known about their clinical associations. We reviewed the literature assessing the associations between thyroid disease and sleep disorders and noted that hyperthyroidism and hypothyroidism have clinical overlap with sleep conditions such as insomnia, restless legs syndrome, and obstructive sleep apnea. These findings highlight the importance of identifying and managing thyroid dysfunction for patients with these common sleep disorders. Additional research is needed to further understand how thyroid dysfunction affects sleep physiology.

Excessive daytime sleepiness in sleep apnea: any role of testosterone or vitamin D?

Recent studies reported association of sleep-disordered breathing (SDB) with testosterone and vitamin D deficiency. Low testosterone and vitamin D levels have been linked to fatigue and excessive daytime sleepiness (EDS). However, the impact of testosterone and vitamin D deficiency on EDS in subjects with SDB remains unknown. The aim of this study was to explore the predictors of EDS in habitual snorers. Role of testosterone, and vitamin D was studied in detail. We also looked for associations between testosterone, vitamin D, and sleep-related indices. We prospectively enrolled 291 consecutive male patients with habitual snoring. Baseline clinical characteristics were recorded on admission. Standard overnight polysomnography was performed to detect SDB, and Epworth Sleepiness Scale (ESS) was used to assess EDS. Blood samples were obtained in a fasting condition in the morning after polysomnography to determine levels of testosterone and vitamin D. Respiratory disturbance index (RDI) (95 % CI: 1.004-1.024, p=0.005) and the use of antihistamines (95 % CI: 1.083-11.901, p=0.037) were the only independent variables significantly associated with EDS in binary logistic regression analysis. In linear multiple regression analysis, body mass index (BMI) (Beta=-0.282, p<0.001) and oxygen desaturation index (Beta=-0.150, p=0.043) were the only independent variables significantly associated with testosterone levels, and BMI (Beta=-0.142, p=0.016) was the only independent variable significantly associated with vitamin D. We failed to find any independent association of testosterone and vitamin D with subjectively rated EDS among habitual snorers. Our results suggest an independent association between the magnitude of nocturnal desaturation and testosterone levels.

Comparison of clinical and polysomnographic parameters between obese and nonobese obstructive sleep apnea

Introduction:

Obstructive sleep apnea (OSA) is one of the most common sleep-disordered breathing characterized by repeated cessation or reduction in airflow during sleep. OSA occurs in both obese and nonobese individual. This study was designed to compare the clinical and polysomnographic data between obese and nonobese patients with OSA.

Materials and Methods:

This was a retrospective study that included all the patients diagnosed as between November 2013 and December 2014. The patients were classified into nonobese (n = 23) and obese (n = 72) groups if their body mass index (BMI) was <27.5 and ≥27.5, respectively. Data were analyzed using Statistical Package for the Social Sciences (SPSS) software program, version 20.0 (SPSS, Chicago, Illinois). A value of P < 0.05 was considered statistically significant.

Results:

There were 95 patients of OSA, of which 23 (44.4%) were nonobese and 72 (75.78%) were obese with a mean BMI of 24.37 ± 3.09 and 34.27 ± 8.34 kg/m², respectively. Characteristics, such as male predominance, higher BMI, neck circumference, and loud snoring, were significantly higher in obese group (P < 0.05) as compared to nonobese. Mild OSA (AHI 5-15) was significantly higher in nonobese patients (39.13% vs. 5.55%, P < 0.00001), whereas severe OSA (AHI >30) was higher in obese patients as compared with nonobese (66.66% vs. 30.43%, P = 0.002). When comparing comorbidities, the hypertension was significantly higher in the obese (47.22% vs. 13.04%, P = 0.003) than the nonobese patients. The incidence of diabetes (37.50% vs. 17.39%) and hypothyroidism (16.66% vs. 4.34%) was also higher in obese group as compared with nonobese. No significant difference was found for mean age, racial origin (Asian/African), and ESS score between obese and nonobese patients.

Conclusion:

Obstructive sleep apnoea is not restricted to only obese individual; rather it also occurs in nonobese. The severity of OSA in nonobese has generally less as compared with obese and its early identification required high index of suspicion.

Update on Persistent Excessive Daytime Sleepiness in OSA

OSA is a highly prevalent sleep disorder, and subjective excessive daytime sleepiness (EDS) is the cardinal symptom for which many individuals seek medical advice. Positive airway pressure (PAP) devices, first-line treatment for OSA, eliminates EDS in most patients. However, a subset of patients suffers from persistent EDS despite adherence to therapy. Multiple conditions, some reversible, could account for the residual sleepiness and need to be explored, requiring detailed history, review of PAP data from the smart card, and sometimes additional testing. When all known causes of EDS are excluded, in adequately treated subjects, the purported mechanisms could relate to long-term exposure to the OSA-related sleep fragmentation, sleep deprivation, and hypoxic injury to the arousal system, shifts in melatonin secretion, or altered microbiome. Independent of the mechanism, in well-treated OSA, pharmacological therapy with approved drugs can be considered. Modafinil is commonly prescribed to combat residual EDS, but more recently two drugs, solriamfetol, a dual dopamine-norepinephrine reuptake inhibitor, and pitolisant, a histamine H3 receptor inverse agonist, were approved for EDS. Solriamfetol has undergone randomized controlled trials for treatment of EDS associated with both OSA and narcolepsy, exhibiting robust efficacy. Solriamfetol is renally excreted, with no known drug interactions. Pitolisant, which is nonscheduled, has undergone multiple RCTs in narcolepsy, showing improvement in subjective and objective EDS and one OSA trial showing improvement in subjective EDS.

Hypothyroidism and Its Association With Sleep Apnea Among Adults in the United States: NHANES 2007-2008

CONTEXT

The association between hypothyroidism and sleep apnea (SA) has been studied, but results are conflicting and based mostly on small studies.

OBJECTIVE

To determine whether there is a positive association between hypothyroidism and SA in the US population.

DESIGN

Cross-sectional study.

SETTING

US National Health and Nutrition Examination Survey, 2007-2008.

PARTICIPANTS

We included all subjects ≥18 years old who met inclusion criteria. Participants not on antithyroid medication with a TSH >5.6 mIU/L and those on thyroid hormone replacement regardless of TSH were categorized as hypothyroid. Participants not on thyroid hormone replacement or antithyroid medication who had a TSH ≥0.34 and ≤5.6 mIU/L were categorized as euthyroid. The diagnosis of SA was based on participants' response when asked whether they had been diagnosed with SA by their doctors.

MAIN OUTCOME MEASURES

Multivariate logistic regression analyses were performed to determine the association between hypothyroidism and SA.

RESULTS

A total of 5515 adults were included for data analysis. The prevalence of hypothyroidism and hyperthyroidism was calculated at 9.47% and 1.19%, respectively. Multivariate logistic regression analysis adjusted for demographics, health care access, body mass index, socioeconomic factors, alcohol use, smoking, and other comorbidities demonstrated a significant association between hypothyroidism and SA (OR = 1.88, 95% CI, 1.24 to 2.84, P < 0.01).

CONCLUSION

Hypothyroidism is associated with SA after adjustment for potential confounding variables.

[Pathophysiological aspects of neuro-endocrine regulation system in patients with obstructive sleep apnea syndrome]

AIM

To reveal the changes in the pituitary-thyroid, pituitary-gonadal, adrenal components and in the prolactinergic system of neuroendocrine regulation in patients with severe obstructive sleep apnea syndrome (OSAS).

MATERIAL AND METHODS

The study involved 51 men aged 46-55 years. The main group (BG) included 37 patients with severe OSAS. The duration of clinical manifestations of OSAS was 10.5±1.5 years. OSAS was verified on the basis of clinical and functional studies and polysomnographic monitoring in accordance with the AASM criteria (2014). The control group (CG) consisted of 14 age-matched men without sleep-disordered breathing. The body mass index in BG was 34.2±1.8 compared to 28.2±2.1 kg/m² in CG. Serum concentrations of thyroid-stimulating hormone (TTG), free thyroxine (T4), triiodothyronine (T3), cortisol, prolactin, testosterone, luteonizing (LH) and follicle-stimulating (FSH) hormones were determined by the immunoradiological method using the standard DIA test system (Russia) and the analyzer 'Immunotest-800'.

RESULTS

Patients with severe OSAS had decreased concentration of free thyroxine (T4) and decreased activity of thyroid stimulating hormone (TSH) (р<0.001), increased concentration of prolactin and cortisol (р<0.001), decreased concentration of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone compared to the controls (р<0.001).

CONCLUSION

The changes in the hypothalamic-pituitary-gonadal system are a manifestation of disturbances of the mechanisms of self-regulation and compensation that indicates the presence of maladaptive reactions of the neuroendocrine system.

Lack of associations between thyroid function and obstructive sleep apnea severity in adults with prediabetes and diabetes mellitus

PURPOSE

Hypothyroidism is associated with a high frequency of obstructive sleep apnea (OSA). However, the prevalence of OSA in hypothyroid patients is not different from the general population in many reports. The importance of thyroid function screening in sleep-disordered breathing is still controversial. This study aimed to explore the association between thyroid dysfunction and OSA in the adults with prediabetes or diabetes mellitus type 2, who have very high prevalence of OSA.

METHODS

OSA was assessed using an in-home monitoring device, WatchPAT200. OSA severity was measured using apnea-hypopnea index (AHI), oxygen desaturation index (ODI), minimum oxygen saturation (minO2), and time spent under oxygen saturation < 90% (T90). Patients with pre-existing thyroid dysfunction were excluded.

RESULTS

Participants included 70 men and 118 women with mean age 52.8 ± 10.9 years and body mass index 28.2 ± 4.9 kg/m². One hundred forty participants (75%) had OSA, with a median AHI of 10.1 (interquartile range 4.8, 18.3). The percentage of positive thyroid autoantibody (thyroperoxidase and thyroglobulin antibody) was similar among the subjects with and without OSA. There was no correlation between the levels of thyroid function (TSH, FT3, FT4, TSH/FT3, and TSH/FT4 ratio) and the severity indices of OSA (AHI, ODI, minO2, and T90).

CONCLUSIONS

These data do not support universal screening for thyroid dysfunction in OSA patients with diabetes or prediabetes.

Abnormal thyroid hormones and non-thyroidal illness syndrome in obstructive sleep apnea, and effects of CPAP treatment

OBJECTIVE

In obstructive sleep apnea (OSA), while both hypothyroidism and hyperthyroidism have been studied, the occurrence of non-thyroidal illness syndrome (NTIS) (normal thyroid stimulating hormone [TSH] with low triiodotironine) has not been investigated. We explored the occurrence of NTIS in patients with moderate to severe OSA and its relationship to the severity of nocturnal respiratory disorders. We also studied the occurrence of subclinical hypothyroidism (SH, ie, high TSH with normal thyroxine) in OSA and changes in circulating TSH, free triiodotironine (fT3) and free thyroxine (fT4) after CPAP treatment.

METHODS

After a nocturnal respiratory polysomnography, 125 consecutive patients with moderate to severe OSA and 60 control subjects with normal nocturnal respiration were recruited. Morning circulating TSH, fT3, and fT4 were measured in all subjects. In a subsample of patients, nocturnal polysomnography and hormonal determinations were repeated after CPAP treatment for five months.

RESULTS

NTIS was found in 13 (10.4%), and SH in ten (8%) OSA subjects, but not in any control subjects. Patients with NTIS showed worse mean nocturnal oxygen saturation and time with saturation <90% (both p < 0.001). After treatment, NTIS subjects (n = 13) showed an increase in fT3 (p < 0.001) to the normal range, and SH subjects (n = 6) a slight decrease in TSH (p = 0.01). In the patients with normal hormones before treatment (n = 45), no change was observed.

CONCLUSIONS

NTIS may occur in OSA patients with severe nocturnal hypoxemia. OSA treatment is followed by an improvement in TSH in patients with abnormal baseline levels of this hormone, and by recovery of NTIS.

The effect of obstructive sleep apnea syndrome and hypothyroidism to intima-media thickness of carotid artery

AIM

Obstructive sleep apnea syndrome (OSAS) is a common disorder and in subjects with OSAS the prevalence of hypothyroidism is approximately 1.2-11 %. The episodes of hypoxia/reoxygenation associated with the respiratory disturbances observed in subjects with OSAS increases the risk of cardiovascular diseases. Hypothyroidism; primary or subclinical, has several effects on cardiovascular system. In our study, we investigated carotid artery intima-media thickness (IMT) which is an early sign of atherosclerosis, in OSAS subjects with hypothyroidism.

MATERIALS AND METHOD

Subjects who admitted to Kahramanmaras Necip Fazıl City State Hospital Chest Diseases out-patient clinic between May 2014 and January 2016 for snoring and had polysomnographic evaluation at the sleep laboratory were included in this study. Each subject was evaluated for serum thyroid function tests and carotid artery IMT was measured by a Doppler ultrasound.

RESULTS

Mean carotid artery IMT values in the isolated OSAS, OSAS plus hypothyroidism, and control groups were 0.67 ± 0.12, 0.8 ± 0.12, and 0.54 ± 0.08 mm, respectively; difference between groups was statistically significant (p < .05). A poXsitive correlation was found between thyroid stimulating hormone levels and IMT (r = 0.426, p = .002), while free T3 levels and IMT were negatively correlated (r = -0.463, p = .001). IMT and apnea-hypopnea index were also positively correlated (r = 0.403, p = .003).

CONCLUSION

We suggest, physicians should be alert for hypothyroidism comorbidity in OSAS, and suspected subjects with OSAS should be screened for hypothyroidism considering the potential cardiovascular complications.

Role of hypothyroidism in obstructive sleep apnea: a meta-analysis

OBJECTIVE

This study evaluates the role of hypothyroidism in obstructive sleep apnea (OSA) by comparing the OSA indices in hypothyroid OSA (OSA-HYPOT) with euthyroid OSA (OSA-EUTHY) patients.

METHODS

After literature search in several electronic databases and selection of studies by following eligibility criteria, meta-analyses of mean differences/standardized mean differences were performed to compare OSA indices at the time of diagnosis between OSA-HYPOT and OSA-EUTHY patients. Metaregression analyses were carried out to examine the relationship between age, BMI, sample size, and gender vs OSA indices in OSA-HYPOT patients.

RESULTS

Twelve studies and five case reports recruiting 192 OSA-HYPOT and 1423 OSA-EUTHY patients were included in the meta-analysis. Prevalence (mean ± SD) of clinical hypothyroidism in OSA patients was 8.12 ± 7.13% and that of subclinical hypothyroidism 11.07 ± 8.49%. Apnea-Hypopnea Index, time of sleep with oxygen desaturation <90%, and Epworth Sleepiness Scale were significantly higher in the OSA-HYPOT patients at diagnosis, whereas there was no significant difference in arousal index, respiratory disturbance index and sleeping efficiency between OSA-HYPOT and OSA-EUTHY patients. Body mass index was positively associated with Apnea-Hypopnea Index in OSA-HYPOT patients.

CONCLUSIONS

Hypothyroidism is found to be associated with severity of OSA. However, obesity can be a confounder in the outcomes observed herein.

Thyroid Stimulating Hormone Is Increased in Hypertensive Patients with Obstructive Sleep Apnea

Purpose. To evaluate alteration in serum TSH in hypertensives with OSA and its relation with cardiometabolic risk factors. Methods. 517 hypertensives were cross-sectionally studied. OSA was determined by polysomnography and thyroid function by standard methods. Results. OSA was diagnosed in 373 hypertensives (72.15%). Prevalence of subclinical hypothyroidism was significantly higher in OSA hypertensives than in non-OSA ones (15.0% versus 6.9%, P = 0.014). Serum LnTSH in hypertensives with severe OSA was significantly higher (0.99 ± 0.81 versus 0.74 ± 0.77 μIU/mL, P < 0.05) than in those without OSA. AHI, LSaO₂, ODI₃, and ODI₄ were independently associated with serum TSH for those aged 30-65 years. Dividing subjects into four groups as TSH < 1.0 μIU/mL, 1.0 ≤ THS ≤ 1.9 μIU/mL, 1.91 ≤ TSH < 4.5 μIU/mL, and TSH ≥ 4.5 μIU/mL, only 26.3% of OSA subjects exhibited TSH between 1.0 and 1.9 μIU/mL, significantly less than non-OSA subjects (26.3% versus 38.2%, P = 0.01). DBP and serum LDL-c elevated with TSH increasing and were only significantly higher in TSH ≥ 4.5 μIU/mL group than in 1.0 ≤ TSH ≤ 1.9 μIU/mL group (96.32 ± 14.19 versus 92.31 ± 12.86 mmHg; P = 0.040; 0.99 ± 0.60 versus 0.87 ± 0.34 mmol/L, P = 0.023). Conclusion. OSA might be a risk factor for increased TSH even within reference range in hypertensive population.

Sleep apnea syndrome in endocrine clinics

Obstructive sleep apnea syndrome (OSAS) is a chronic condition with a high prevalence (up to 7 % of the general population) characterized by frequent episodes of upper airway collapse while sleeping. Left untreated, OSAS can cause severe complications, including systemic hypertension, cardiovascular disease, stroke, and abnormal glucose metabolism. This review aims to summarize the close links between OSAS, endocrinology, and metabolism. In patients with metabolic syndrome, OSAS is an independent risk factor for the onset of type 2 diabetes and a worsening glycemic control. The accumulation of adipose tissue in the neck and limited chest wall dynamics, hypoxia, and local micro-inflammation link visceral obesity closely with OSAS. There is now an abundance of convincing data indicating that promoting lifestyle changes, improving sleep hygiene, and adjusting diet can ameliorate both metabolic syndrome and OSAS, especially in obese patients. The incidence of OSAS in acromegaly is high, though GH treatments seem to be unrelated to the onset of apnea in GH-deficient individuals. Prospective studies have suggested an association between hypertension and OSAS because intermittent nocturnal hypoxia prompts an increase in sympathetic tone, endothelial dysfunction, and vascular inflammation: aldosterone excess may have a pathophysiological role, and some authors have reported that treating OSAS leads to a modest, but significant, reduction in blood pressure.