Vitamin D status of male OSAS patients improved after long-term CPAP treatment mainly in obese subjects

Vitamin D deficiency: A forgotten aspect in sleep disorders? A critical update

Over the past few years, there has been a surge in interest regarding the connection between sleep duration and quality, sleep disorders, mainly Obstructive sleep apnoea (OSA) and Vitamin D. There is growing evidence to support a new role of Vitamin D in the maintenance and regulation of optimal sleep. Furthermore, a notable link has been identified between OSA and a decrease in serum Vitamin D levels, which appears to intensify as the severity of sleep apnea worsens. Vitamin D status could also potentially serve as a mediator or provide an explanation for the association between OSA and cardiometabolic morbidity, but the current state of research in this area is inadequate. Studies have indicated that the supplementation of Vitamin D can optimize sleep quality, presenting more proof of the connection between insufficient vitamin D levels and sleep disorders. However, it is unclear whether low serum Vitamin D levels are a contributing factor to OSA development or if OSA predisposes individuals to Vitamin D deficiency. As a result, various studies have endeavored to examine the complex relationship between OSA and Vitamin D deficiency. In children and adolescents, while data is limited, there seems also to be a link between sleep disorders and Vitamin D levels. Therefore, the objective of this review is to provide a comprehensive overview of the current evidence on the association between Vitamin D and sleep disorders in both adults and children.

Obstructive sleep apnea and vitamin D level: Has the dust settled?

Obstructive sleep apnea and vitamin D deficiency are associated with multiple complications with increased morbidity and mortality. However, the relationship between these two entities remains unclear, with clinical studies demonstrating contradictory results. This narrative review aims to present the current evidence and understanding of this relationship and discuss the possible mechanisms linking these two disease entities. Finally, we summarize and propose areas of opportunity for future research.

Exploring the link between vitamin D deficiency and obstructive sleep apnea: A comprehensive review

Despite the high prevalence and significant health burden of obstructive sleep apnea (OSA), its underlying pathophysiology remains incompletely understood. This comprehensive review explores the emerging connection between vitamin D deficiency and OSA, discusses potential mechanisms underlying this association, and explores the therapeutic implications of these findings. Recent research has consistently highlighted the high incidence of vitamin D deficiency among patients with OSA, which often occurs independently of geographical location. This suggests that factors beyond lack of sunlight exposure may be involved. This review also discusses how reduced vitamin D may be associated with more severe manifestations of OSA. In addition, it explores the potentiality of using vitamin D supplements as a therapeutic strategy for OSA, noting that some studies have found improvements in sleep quality and a reduction in OSA severity. Potential mechanisms are proposed, including the role of vitamin D deficiency in promoting inflammation, oxidative stress, hypoxia, impairing immune function, muscle function, and gene polymorphism of vitamin D receptors, all of which could contribute to the pathogenesis of obstructive sleep apnea. The paper underscores the need for future research to validate these observations, to determine optimal vitamin D supplementation dosage and duration, to explore potential side effects and risks, and to investigate potential interactions with other treatments.

Continuous positive airway pressure treatment improves bone mineral density in men affected by severe obstructive sleep apnea syndrome

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) and low bone mineral density (BMD) are 2 prevalent conditions with a significant negative impact on patients' well-being and quality of life. Recent research has shown low BMD at different bone sites in male patients with OSA. Although the efficacy of continuous positive airway pressure (CPAP) treatment for OSA has been widely demonstrated, the evidence for understanding its impact on BMD and other bone-related outcomes is insufficient. The aim of this observational study was to investigate the effect of 12 months of CPAP treatment on lumbar and femur BMD and bone-related serum biomarkers in male patients with severe OSA.

METHODS

Sixty patients (mean age: 55.1 ± 9.9 years) were consecutively included and underwent BMD measurement with dual-energy x-ray absorptiometry at baseline and after 12 months of CPAP treatment. Vitamin D, parathyroid hormone, and calcium serum levels were examined at the same time points.

RESULTS

A significant increase in BMD in the L1 (P < .001, d = 0.27) and L2 (P < .001, d = 0.26) vertebrae was observed after CPAP treatment, along with an increase in vitamin D (P < .001, d = 0.71) and calcium (P < .001, d = 0.73) levels and a decrease in parathyroid hormone levels (P < .001, d = 0.60). The increase in BMD in L1 was significantly correlated with the decrease in parathyroid hormone serum levels (r = -.50, P < .001).

CONCLUSIONS

Overall, these findings showed that beneficial OSA treatment might restore bone health and support CPAP treatment as a feasible strategy to improve BMD in male patients with severe OSA. Accordingly, diagnosing and targeting OSA may be warranted in the treatment of male patients with undetermined osteopenia and osteoporosis.

CITATION

Carpi M, Cordella A, Placidi F, et al. Continuous positive airway pressure treatment improves bone mineral density in men affected by severe obstructive sleep apnea syndrome. J Clin Sleep Med. 2024;20(1):67-73.

Obstructive sleep apnea and vitamin D: an updated systematic review and meta-analysis

PURPOSE  : Obstructive sleep apnea (OSA) is a chronic, sleep-related breathing disorder which leads to increased cardiovascular risks. Vitamin D deficiency is associated with various cardiometabolic complications, including increased cardiovascular morbidity and mortality. We aimed to analyze the difference in serum 25-hydroxyvitamin D (25-OHD) level, prevalence of vitamin D insufficiency and deficiency, and the effect of CPAP treatment on serum 25-OHD levels among adult patients with OSA.

METHODS

We pooled data from 18 observational studies involving 5592 individuals. Baseline parameters that might have contributed to the significant differences observed were also analyzed.

RESULTS

Patients with OSA had significantly lower serum 25-OHD levels (pooled d +  - 0.74 [95% CI: - 1.19 to - 0.28], p < 0.01) and higher prevalence of vitamin D deficiency (pooled log (odds ratio) 0.98 [95% CI: 0.30 to 1.67], p < 0.01) compared to those without OSA. Subgroup analysis demonstrated that these differences were significant only in moderate OSA and severe OSA. Neither age nor BMI nor geographical latitude contributed significantly to the differences observed in serum 25-OHD levels. The use of CPAP did not lead to significant changes in serum 25-OHD levels.

CONCLUSION

Patients with OSA have lower serum 25-OHD levels with a higher prevalence of vitamin D deficiency, regardless of age or BMI, pointing to an independent association between vitamin D and OSA.

Severe Vitamin D Deficiency-A Possible Cause of Resistance to Treatment in Psychiatric Pathology

In the last few years, vitamin D functions have been studied progressively, and along with their main role in regulating calcium homeostasis, the potential function in the nervous system and the link between different psychiatric disorders and vitamin D deficiency have been revealed. The discovery of vitamin D receptors in multiple brain structures, like the hippocampus, led to the hypothesis that vitamin D deficiency could be responsible for treatment resistance in psychiatric diseases. The aim of this study was to analyze the current knowledge in the literature regarding vitamin D deficiency among individuals afflicted with psychiatric disorders and assess the potential therapeutic benefits of vitamin D supplementation. A systematic search was conducted on the PubMed database for articles published in the last five years (2016-2022) in English, focusing on human subjects. Results show that vitamin D deficiency has implications for numerous psychiatric disorders, affecting mood and behavior through its influence on neurotransmitter release, neurotrophic factors, and neuroprotection. It also plays a role in modulating inflammation, which is often elevated in psychiatric disorders. In conclusion, vitamin D deficiency is prevalent and has far-reaching implications for mental health. This review underscores the importance of exploring the therapeutic potential of vitamin D supplementation in individuals with psychiatric disorders and highlights the need for further research in this complex field.

Vitamin D Levels in Patients with Overlap Syndrome, Is It Associated with Disease Severity?

Background: The coexistence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) has been defined as overlap syndrome (OVS). Recently, a link between OSA, COPD and Vitamin D (Vit D) serum concentration was reported, however, evidence regarding Vit D status in patients with OVS is scarce. The aim of the present study was to evaluate Vit D serum levels and to explore the association of those levels with anthropometric, pulmonary function and sleep parameters in patients with OVS. Methods: Vit D serum levels were measured in patients diagnosed with OVS, as confirmed by overnight polysomnography and pulmonary function testing. Results: A total of 90 patients (79 males and 11 females) were included in the analysis. The patients were divided into three groups matched for age, gender, and BMI: the control group that included 30 patients (27 males and 3 females), the OSA group that included 30 patients (26 males and 4 females), and the OVS group that included 30 patients (26 males and 4 females). Patients with OVS exhibited decreased serum 25(OH)D levels compared with OSA patients and controls (14.5 vs. 18.6 vs. 21.6 ng/mL, p < 0.001). In the OVS group, multiple linear regression analysis identified AHI and FEV1, as predictors of serum 25(OH)D levels (p = 0.041 and p = 0.038, respectively). Conclusions: Lower Vit D levels have been observed in patients with OVS compared with OSA patients and non-apneic controls, indicating an increased risk of hypovitaminosis D in this population which might be associated with disease severity.

Sleep duration as an independent factor associated with vitamin D levels in the EPISONO cohort

STUDY OBJECTIVES

Obstructive sleep apnea and short sleep duration have been separately associated with inadequate serum 25-hydroxyvitamin D [25(OH)D] levels. However, whether these 2 factors may concurrently influence 25(OH)D in the general population is unknown. We hypothesized that both obstructive sleep apnea and short sleep duration would be independently associated with lower concentrations of 25(OH)D in a sex-dependent manner.

METHODS

In this cross-sectional study, 712 individuals, part of the prospective EPISONO cohort (Brazil), underwent polysomnography, answered sleep questionnaires, and had their blood collected for serum 25(OH)D quantification.

RESULTS

Individuals with a sleep duration of < 6 hours had 2-fold increased odds of 25(OH)D < 20 ng/mL compared with those who reported 6 or more hours of sleep, even after adjusting for confounding factors. Subset sex analysis revealed that men with a sleep duration of < 6 hours had 4-fold increased odds of 25(OH)D < 20 ng/mL. In women, short sleep duration was not associated with lower 25(OH)D levels. The presence of obstructive sleep apnea (as classified according to the individual's apnea-hypopnea index) was not independently related to 25(OH)D concentrations in men or women. Sleep parameters, including sleep latency and sleep efficiency, had no association with 25(OH)D < 20 ng/mL.

CONCLUSIONS

Short sleep, but not apnea-hypopnea index, was an independent factor associated with low 25(OH)D serum levels in men, but not in women. Apnea-hypopnea index scores were not associated with 25(OH)D levels in either sex. These results raise the possibility of investigating sex-specific characteristics, such as gonadal hormone regulation, and re-evaluating obstructive events by classifying them in mild, moderate, and severe obstructive sleep apnea.

CITATION

de Oliveira DL, Dokkedal-Silva V, Fernandes GL, Kim LJ, Tufik S, Andersen ML. Sleep duration as an independent factor associated with vitamin D levels in the EPISONO cohort. J Clin Sleep Med. 2021;17(12):2439-2449.

Association between Interleukin-6 and vitamin D serum levels in patients with obstructive sleep apnea syndrome and impact of long-term continuous positive airway pressure therapy on biomarker levels

OBJECTIVE

Hypoxia induces interleukin-6 (IL-6) production in obstructive sleep apnea syndrome (OSAS). Low serum 25 hydroxyvitamin D (25(OH)D) levels have been linked to OSAS susceptibility. Serum 25(OH)D levels have been negatively correlated with serum IL-6 levels in patients with chronic inflammation. No data exist to assess whether there is a correlation between 25(OH)D and IL-6 serum levels in OSAS, while the impact of continuous positive airway pressure (CPAP) therapy on IL-6 or 25(OH)D levels needs further investigation. We aimed to compare the serum 25(OH)D and IL-6 levels between OSAS patients and controls, examine a possible correlation between 25(OH)D and IL-6 levels and the changes of their concentrations after twelve months of CPAP therapy in OSAS patients.

METHODS

15 newly-diagnosed OSAS patients and 15 non-apneic controls were recruited. Serum IL-6 and 25(OH)D levels were measured in the study population at baseline and twelve months after CPAP initiation in OSAS patients.

RESULTS

IL-6 levels were elevated in OSAS patients than controls and were positively and negatively correlated with body mass index (BMI) and minimum oxyhemoglobin saturation (minSpO₂), respectively. Diabetes mellitus, BMI and minSpO₂ independently predicted IL-6 levels. No difference was found in 25(OH)D levels between groups. No correlation between IL-6 and 25(OH)D levels was detected. Effective CPAP therapy did not impact IL-6 or 25(OH)D levels after one year in OSAS patients.

CONCLUSIONS

No correlation between IL-6 and 25(OH)D levels was found. IL-6 levels were significantly elevated in OSAS patients than the controls and positively correlated with BMI, diabetes mellitus, and nocturnal hypoxemia.

The Importance of Diagnosing and the Clinical Potential of Treating Obstructive Sleep Apnea to Delay Mild Cognitive Impairment and Alzheimer's Disease: A Special Focus on Cognitive Performance

Obstructive sleep apnea (OSA) is a highly frequent sleep disorder in the middle-aged and older population, and it has been associated with an increased risk of developing cognitive decline and dementia, including mild cognitive impairment (MCI) and Alzheimer's disease (AD). In more recent years, a growing number of studies have focused on: 1) the presence of OSA in patients with MCI or AD, 2) the link between OSA and markers of AD pathology, and 3) the role of OSA in accelerating cognitive deterioration in patients with MCI or AD. Moreover, some studies have also assessed the effects of continuous positive airway pressure (CPAP) treatment on the cognitive trajectory in MCI and AD patients with comorbid OSA. This narrative review summarizes the findings of studies that analyzed OSA as a risk factor for developing MCI and/or AD in the middle-aged and older populations with a special focus on cognition. In addition, it describes the results regarding the effects of CPAP treatment in hampering the progressive cognitive decline in AD and delaying the conversion to AD in MCI patients. Considering the importance of identifying and treating OSA in patients with MCI or AD in order to prevent or reduce the progression of cognitive decline, further larger and adequately powered studies are needed both to support these findings and to set programs for the early recognition of OSA in patients with cognitive impairment.

Vitamin D in obesity and obesity-related diseases: an overview

Hypovitaminosis D and obesity represent two pandemic conditions sometimes associated with each other. Although it is known that there is a close relationship between these two health problems, the underlying pathophysiological mechanism has not yet been fully clarified. In fact, on the one hand, obesity per se seems to involve low circulating levels of vitamin D due to low sun exposure, physical activity, and intake of foods rich in vitamin D, volumetric dilution and sequestration in the adipose tissue. Conversely, since preadipocytes and adipocytes express the receptors and are involved in the metabolism of vitamin D it would seem that low levels of this vitamin may be involved in adipogenesis and therefore in the development of obesity. This connection is extremely important when considering obesity-related diseases. In fact, low vitamin D levels and severe obesity are significantly associated with some cardio-metabolic risk factors, including high Body Mass Index, waist circumference, blood pressure, impaired lipid and glycemic profile and insulin resistance, as they would seem associated with worse cardiovascular outcomes and higher cancer incidence and mortality. Therefore, the purpose of this review was to examine the recent evidence linking low vitamin D status, obesity and obesity-related diseases, highlighting the scientific achievements and the gaps to be filled with further investigations.

The association between serum vitamin D and obstructive sleep apnea: an updated meta-analysis

Background

The objective was to determine whether OSA patients have a low serum vitamin D level by systematic review and meta-analysis.

Methods

This study searched the following electronic bibliographic databases: Embase, Medline, Web of Science, PubMed, VIP, Wanfang, CNKI and SinoMed. All data were searched between January 2000 and August 2020. The quality of the included studies was estimated by two researchers according to the Newcastle–Ottawa Scale and Agency for Healthcare Research and Quality. All qualified studies and statistical analyses were conducted using RevMan 5.2.

Results

Twenty-nine eligible studies compromising 6717 participants met the inclusion criteria of the meta-analysis. The results revealed that the serum 25(OH)D level was significantly lower in OSA patients than the controls. According to the severity of the disease, subgroup analysis was performed; the results demonstrated that the serum 25(OH)D level was not decreased in mild OSA patients compared with the controls, while the serum 25(OH)D level in moderate and severe OSA patients was lower than that in the controls. Furthermore, based on ethnicity, BMI, PSG type, study quality and latitude, the subjects were divided into different subgroups for meta-analysis. The results revealed that the serum 25(OH)D level in all OSA subgroups was decreased compared with that in the control group.

Conclusions

The present meta-analysis shows that the serum vitamin D level was different between OSA patients and healthy people. OSA patients could have a low serum vitamin D level.

Serum vitamin D levels in patients with obstructive sleep apnea syndrome and level changes after continuous positive airway pressure therapy

PURPOSE

Patients with obstructive sleep apnea syndrome (OSAS) have been found to exhibit lower serum vitamin D levels, even when the control groups are matched for confounding conditions. However, contradictory studies are also present. This study aimed to compare serum 25-hydroxyvitamin D (25(OH)D) levels between adult patients with OSAS and non-apneic controls and to evaluate the changes in 25(OH)D levels after 3 and 12 months of continuous positive airway pressure (CPAP) therapy.

METHODS

The study was comprised of 30 patients with OSAS and 30 controls. Serum 25(OH)D levels were determined at baseline and after 3 and 12 months of CPAP therapy in all patients with OSAS. For analysis, patients with OSAS were divided into subgroups by adherence, with adherence defined as CPAP usage for > 4 h per night on at least 70% of nights.

RESULTS

The 25(OH)D levels were not significantly different between OSAS and control groups at baseline. 25(OH)D levels did not change after 3 and 12 months of CPAP therapy. Patients who were CPAP-adherent showed less reduction in 25(OH)D levels compared with non-adherent ones (21.18 ± 9.3 vs. 12.13 ± 3.8 ng/mL, p = 0.022) after 1 year. The 25(OH)D levels were significantly correlated with higher daily CPAP usage at 3 and 12 months. Mean daily CPAP usage was a significant predictor of serum 25(OH)D levels at 12 months.

CONCLUSIONS

Patients with OSAS who demonstrated good CPAP adherence showed significantly higher 25(OH)D levels after 1 year compared with those not adequately using CPAP. Long-term good CPAP adherence and highly daily CPAP usage positively affected 25(OH)D levels in patients with OSAS.

25-hydroxyvitamin D levels in patients with obstructive sleep apnea and continuous positive airway pressure treatment: a brief review

The aim of the present study is to summarize the information available, to time, regarding the relationship between obstructive sleep apnea (OSA) and vitamin-D (vD) levels. Moreover, the association between vD deficiency and OSA severity will also be examined. At the end of the present study the possible advantageous effect of CPAP on vD-levels will be summarized. Extensive literature search was conducted in PubMed, Scopus, The Cochrane Library and Embase database. 13 articles were found concerning OSA and vD, of which 2 articles included treatment with a CPAP. Patients with OSA exhibit low levels of vD in the blood serum, and women present an even lower mean value than men. Lack of VD in blood serum seems to be related to the severity of the OSA syndrome, and to the short duration of sleep. OSA patients with concurrent metabolic syndrome exhibit lower serum vD-levels, as compared with those without metabolic syndrome. Long-term continuous positive airway pressure treatment (CPAP) treatment can increase vD-levels in male OSA patients while no change is observed in women. OSA patients demonstrate lower levels of vD in multiple studies. The severity of the OSA may be associated with vD-levels and deficiency, however more studies are needed to assess that relationship due to contradictions in current bibliography. CPAP can increase vD-levels in male patients. The relation between vD and OSA and/or CPAP is important but recent; therefore further research is needed about the exact relationship to be clarified. Also, the effect of gender hormones on vD regulation in OSA patients should be further investigated.

Vitamin D deficiency in patients evaluated for obstructive sleep apnea: is it associated with disease severity?

PURPOSE

The aim of the present study was to assess vitamin D levels in a large cohort of OSA patients and to investigate possible correlations with clinical and polysomnographic parameters.

METHODS

In this cross-sectional study, 685 consecutive patients underwent type 1 polysomnography (PSG) for OSA diagnosis. They were grouped according to apnea-hypopnea index (AHI) as mild, moderate, and severe. Patients with AHI < 5 served as controls. Demographic, PSG data, and serum levels of vitamin D were measured and compared between groups.

RESULTS

OSA was diagnosed in 617 of the patients (90%). Of those, 94 (15%) had mild OSA, 150 (24%) moderate OSA, and 373 (61%) severe OSA. The risk of vitamin D deficiency (< 20 ng/mL) was observed in 38% of the cohort. OSA patients had lower vitamin D levels compared to controls (23 ng/mL vs 26 ng/mL, p = 0.006). The lowest levels of vitamin D [mean 21] (p < 0.001 among all groups) and the higher prevalence for vitamin D deficiency (45%) were observed in severe OSA patients. After multiparametric adjustments for age, gender, obesity, and comorbidities, severe OSA showed significant independent associations with the risk of vitamin D deficiency [OR (95% CI) 2.002 (1.049-3.819), p = 0.035].

CONCLUSIONS

A large proportion of patients referred for OSA evaluation had vitamin D deficiency, which was independently associated with severe OSA. However, further research is needed in order to determine the role of vitamin D in OSA patients.

Influence of Body Mass Index on Survival and Prognosis in Squamous Cell Carcinoma of Head and Neck

OBJECTIVE

Differences in body mass index (BMI) were used to analyze the survival and prognosis of SCCHN patients.

PATIENTS AND METHODS

A retrospective cohort study was conducted to select 323 patients who underwent surgical treatment for SCCHN from June 2013 to June 2016. The patients were divided into a healthy BMI group (BMI<24kg/m2), an overweight group (24kg/m2≤BMI<28kg/m2) and an obese group (BMI≥28 kg/m2). Various statistical methods were used to summarize and analyze clinical data, complications, disease specific survival (DSS), the overall survival (OS), and recurrence-free survival (RFS) within the last 3 y.

RESULTS

At 3 y, OS (54.40%) and DSS (51.94%) were slightly lower in the obese group compared with the overweight (64.62%, 61.92%) and healthy BMI groups (64.66%, 65.02%), but no statistical significance was found in DSS (P=0.178), OS (P=0.123) and RFS (P=0.362). The difference in operation duration (P=0.008) and bleeding volume (P=0.001) in obese patients was consistent with those in diabetes mellitus (P=0.002) and coronary heart disease (P=0.000). A high incidence of pharyngeal fistula was observed in obese (P=0.014) and overweight patients (P=0.025), but mouth floor fistula (P=0.038), lung infection (P=0.047), fat liquefaction (P=0.003) and lower extremities deep venous thrombosis (P=0.020) were only found in the obese group. Cox univariatable and multivariatable analysis showed that clinical stage, T stage, and N stage were independent prognostic factors for patients with SCCHN, which was not related to BMI.

CONCLUSION

BMI was associated with a higher probability of complications. However, BMI had no significant correlation with 3-year OS, RFS and DSS, and was not a prognostic indicator for patients with SCCHN.

Sleep duration is associated with vitamin D deficiency in older women living in Macao, China: A pilot cross-sectional study

Chinese women are known to have both a high prevalence of metabolic syndrome (MetS) and vitamin D deficiency (serum 25-hydroxyvitamin D (25OHD) <50 nmol/l). Associations between sleep duration and circulating 25OHD have recently been reported but, to our knowledge, these associations have not been studied in older Chinese populations. We thus investigated whether sleep duration was associated with vitamin D status in a population from Macao, China, and whether sleep duration modified the association between MetS and vitamin D deficiency. In 207 older (>55 years) Macanese, anthropometry, blood samples and validated questionnaires, including sleep duration and cardiovascular risk factors, were simultaneously collected. On multivariable categorical analyses, those women, not men, who had short sleep duration (≤6 hours (h)) were at a 2-fold risk for vitamin D deficiency (both <50 nmol/L and <37 nmol/L; OR = 1.94, 95%CI 1.29–2.92; OR = 2.05, 95%CI 1.06–3.98, respectively) and those who had longer sleep duration (>8 h) were 3-fold more likely to have vitamin D deficiency (OR = 3.07, 95%CI 1.47–6.39; OR = 2.75, 95%CI 1.08–7.00, respectively) compared to those with normal sleep duration (6–8 h). Both women and men with MetS were 2-fold more likely to have vitamin D deficiency (women: OR = 2.04, 95%CI 1.31–3.17; OR = 2.15, 95%CI 1.11–4.17, respectively; men: OR = 2.01, 95%CI 1.23–3.28; OR = 2.04, 95%CI 1.00–4.29, respectively). Moreover, women with both short sleep duration and MetS had an increased risk of vitamin D deficiency (OR = 3.26, 95%CI 1.10–9.64). These associations were not found in those with longer sleep. Men with longer sleep and MetS had a 5-fold risk of vitamin D deficiency (OR = 5.22; 95%CI 2.70–10.12). This association was non-significant for men with shorter sleep. We conclude that both short and long sleep duration were associated with vitamin D deficiency in older Chinese women. Further research is needed in larger cohorts or with intervention studies to further examine the associations between reduced sleep, metabolic syndrome and vitamin D deficiency.

Postural and vestibular changes related to CPAP treatment in moderate-to-severe OSA patients: a 12-month longitudinal study

PURPOSE

To assess whether vestibulo-ocular reflex (VOR) gain, posturography parameters and related clinical outcomes can improve in OSA patients after 12 months of CPAP treatment, taking into consideration that a certain degree of vestibular dysfunction has been identified in these subjects.

METHODS

Vestibular, postural, clinical, and polygraphic parameters were assessed in 32 OSA patients before and after beneficial CPAP treatment by means of video head impulse test (vHIT), static posturography (SP), Dizziness Handicap Inventory (DHI), Epworth Sleepiness Scale (ESS), and Apnea-Hypopnea Index (AHI), respectively, and were compared by means of a "within-subject" ANOVA model and Spearman's rank correlation.

RESULTS

After the 12-month period of treatment, OSA patients demonstrated a significant reduction in AHI values, in both opened and closed eyes conditions of surface and length as well as in power spectra recorded in low, middle, and high frequency interval. Although a significant improvement was also recorded among DHI and ESS scores, VOR gain increase did not survive to post-hoc corrections. Finally, positive correlations between the differences between pre- and post-treatment AHI, ESS, and PS values were found.

CONCLUSIONS

The present work highlighted that postural instability and dizziness-related conditions due to OSA may improve after 12 months of CPAP treatment. Although VOR gain did not demonstrate significant improvement, this study might open future perspectives directed to assessing VOR gain changes after longer periods of CPAP treatment.

The role of vitamin D in obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is a common disorder of multifactorial pathogenesis and is associated with obesity, diabetes and cardiovascular disease. Vitamin D is a fat-soluble vitamin with an important function in calcium absorption and homeostasis, which is also implicated in several nonskeletal conditions. The prevalence of vitamin D deficiency is increasing worldwide and is associated with similar metabolic disturbances to OSAS. Moreover, recent data suggest that in OSAS patients serum levels of vitamin D are lower compared with non-apnoeic subjects. However, the mechanisms linking vitamin D deficiency and OSAS are not completely understood and several hypotheses have been advanced. To date, a limited number of studies have assessed the association between lower serum concentrations of vitamin D and OSAS, and have reported inconsistent results. Similarly, contradictory results have been produced by studies which evaluated the effect of continuous positive airway pressure treatment on serum vitamin D levels. The aim of this review is to summarise current knowledge on the association between OSAS and vitamin D levels.

Due to multiple confounding factors, vitamin D deficiency is common among sleep apnoea patients; thus, screening should be performed when clinically indicatedhttp://ow.ly/L3ow30krmol

Is there an association between vitamin D deficiency and adenotonsillar hypertrophy in children with sleep-disordered breathing?

BACKGROUND

Low vitamin D levels have been linked to the risk of sleep-disordered breathing (SDB) in children. Although adenotonsillar hypertrophy (ATH) is the major contributor to childhood SDB, the relationship between ATH and serum vitamin D is uncertain. We therefore investigated the relationship between vitamin D levels and associated factors in children with ATH.

METHODS

We reviewed data from all children with SDB symptoms who were treated from December 2013 to February 2014. Of these, 88 children whose serum vitamin D levels were measured were enrolled in the study. We divided the children into four groups based on adenoidal and/or tonsillar hypertrophy. We conducted a retrospective chart review to analyze demographic data, the sizes of tonsils and adenoids, serum 25-hydroxy-vitamin D [25(OH)D] level, body mass index (BMI), and allergen sensitization patterns.

RESULTS

Children in the ATH group had a lower mean 25(OH)D level than did those in the control group (p < 0.05). Children with vitamin D deficiencies exhibited markedly higher frequencies of adenoidal and/or tonsillar hypertrophy than did those with sufficient vitamin D (p < 0.05). Spearman's correlation analysis identified an inverse correlation between serum 25(OH)D levels and age, tonsil and adenoid size, and height (all p < 0.05). In a multiple regression analysis, tonsil and adenoid size as well as BMI-z score, were associated with 25(OH)D levels after controlling for age, sex, height, and mite sensitization (p < 0.05).

CONCLUSIONS

Our results suggest that low vitamin D levels are linked to ATH. Both the sizes of the adenoids and tonsils and the BMI-z score were associated with the 25(OH)D level. Therefore, measurement of the serum 25(OH)D level should be considered in children with ATH and SDB symptoms.

Continuous Positive Airway Pressure Treatment May Improve Optic Nerve Function in Obstructive Sleep Apnea: An Electrophysiological Study

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a sleep disorder frequently associated with optic nerve diseases. Moreover, untreated patients with severe OSA may show optic nerve dysfunction as documented by electrophysiological studies using visual evoked potentials (VEP). Because continuous positive airway pressure (CPAP) treatment has proved to restore the physiologic nocturnal breathing, thus preventing nocturnal hypoxemia and reducing inflammation, in this study we tested whether 1-year CPAP treatment may modify VEP responses in patients with severe OSA.

METHODS

VEP were recorded at baseline and after 1 year of CPAP treatment in 20 patients with severe OSA, divided in two groups on the basis of CPAP adherence, and compared to a healthy control group.

RESULTS

Patients with good adherence to CPAP therapy (CPAP+; n = 10) showed VEP P100 amplitude significantly higher than patients with poor adherence to CPAP therapy (CPAP-; n = 10). Moreover, the CPAP+ group showed VEP responses similar to those in the control group (n = 26). Considering the mean difference of VEP responses between baseline and follow-up, the CPAP+ group showed a significant increase in VEP P100 amplitude and a significant decrease in VEP P100 latency compared to the CPAP- group.

CONCLUSIONS

This study documented that CPAP therapy significantly improves VEP in patients with OSA who are adherent to the treatment. We hypothesize that CPAP treatment, minimizing the metabolic, inflammatory and ischemic consequences of OSA, may normalize the altered VEP responses in patients with OSA by restoring and preserving optic nerve function.

Metabolic Syndrome and Vitamin D Levels in Patients with Obstructive Sleep Apnea Syndrome

BACKGROUND

Numerous studies have indicated that obstructive sleep apnea syndrome (OSAS), may contribute to the development of metabolic syndrome (MetS) and diabetes. Moreover, OSAS has been associated with lowered vitamin D (Vit D) levels, but reports are inconclusive. Aim of the study was to compare Vit D levels according to the presence of MetS and its components in OSAS patients.

METHODS

The presence of MetS was evaluated and serum 25-hydroxy vitamin D [25(OH)D] levels were measured in consecutive newly diagnosed, by polysomnography, subjects with OSAS.

RESULTS

A total of 107 subjects (88 men) with OSAS were included in the study. Patients were divided into group A (OSAS with MetS group: 55 subjects) and group B (OSAS without MetS: 52 subjects). There were no differences between the two groups in terms of age, body mass index, and sleep parameters. Patients in group A exhibited higher levels of daytime sleepiness, as expressed by Epworth Sleepiness Scale score (12 ± 5.5 vs. 9.3 ± 4.8 for groups A vs. B, p = 0.008). Serum 25(OH)D levels were significantly decreased in group A, as compared with group B (18 ± 8.6 ng/mL vs. 23.9 ± 14.1 ng/mL, respectively, p = 0.012). Group A was then subdivided in two smaller groups, according to patients' metabolic index: OSAS patients with metabolic score = 3 and OSAS patients with metabolic score >3. Serum 25(OH)D levels were higher in OSAS patients with metabolic score = 3 compared with OSAS patients with metabolic score >3 (19.8 ± 8.9 ng/mL vs. 15.1 ± 7.3 ng/mL respectively, p = 0.038).

CONCLUSIONS

OSAS patients with concurrent MetS exhibit lower serum Vit D levels, as compared with those without MetS.

Changes of vitamin D levels and bone turnover markers after CPAP therapy: a randomized sham-controlled trial

The aim was to investigate whether continuous positive airway pressure treatment could modulate serum vitamin D (25-hydroxyvitamin D) and bone turnover markers (collagen-type 1 cross-linked C-telopeptide, osteocalcin and N-terminal propeptide of type 1 collagen) in secondary analysis from a randomized controlled trial. Sixty-five continuous positive airway pressure-naïve male patients with obstructive sleep apnea (age = 49 ± 12 years, apnea-hypopnea index = 39.9 ± 17.7 events h^-1 , body mass index = 31.3 ± 5.2 kg m^-2 ) were randomized to receive either real (n = 34) or sham (n = 31) continuous positive airway pressure for 12 weeks. At 12 weeks, all participants received real continuous positive airway pressure for an additional 12 weeks. After 12 weeks of continuous positive airway pressure (real versus sham), there were no between-group differences for any of the main outcomes [Δ25-hydroxyvitamin D: -0.80 ± 5.28 ng mL^-1 (mean ± SE) versus 3.08 ± 3.66 ng mL^-1 , P = 0.42; Δcollagen-type 1 cross-linked C-telopeptide: 0.011 ± 0.014 ng mL^-1 versus -0.004 ± 0.009 ng mL^-1 , P = 0.48; Δosteocalcin: 1.13 ± 1.12 ng mL^-1 versus 0.46 ± 0.75 ng mL^-1 , P = 0.80; ΔN-terminal propeptide of type 1 collagen: 2.07 ± 3.05 μg L^-1 versus -1.05 ± 2.13 μg L^-1 , P = 0.48]. There were no further differences in subgroup analyses (continuous positive airway pressure-compliant patients, patients with severe obstructive sleep apnea or sleepy patients). However, after 24 weeks irrespective of initial randomization, vitamin D increased in patients with severe obstructive sleep apnea (9.56 ± 5.51 ng mL^-1 , P = 0.045) and in sleepy patients (14.0 ± 4.69 ng mL^-1 , P = 0.007). Also, there was a significant increase in osteocalcin at 24 weeks (3.27 ± 1.06 ng mL^-1 , P = 0.01) in compliant patients. We conclude that 12 weeks of continuous positive airway pressure did not modulate vitamin D or modulate any of the bone turnover markers compared with sham. However, it is plausible that continuous positive airway pressure may have late beneficial effects on vitamin D levels and bone turnover markers in selected groups of patients with obstructive sleep apnea.

Obstructive sleep apnea and objective short sleep duration are independently associated with the risk of serum vitamin D deficiency

BACKGROUND

Studies demonstrate an association between vitamin D (25(OH)D) deficiency and sleep disturbances, such as obstructive sleep apnea (OSA) and short sleep duration. However, to date, no studies have concurrently and objectively evaluated the effect of these factors on 25(OH)D.

OBJECTIVES

To evaluate whether OSA and objective short sleep duration are independently associated with reduced 25(OH)D in an adult population sample.

METHODS

A cross-sectional study included 657 individuals from the city of Sao Paulo, Brazil, as part of the ERA project. Participants fulfilled questionnaires and underwent clinical evaluation, polysomnography and blood sample collection for 25(OH)D quantification. OSA was classified into three categories (mild, moderate and severe). The risk of 25(OH)D deficiency was considered as levels<30 ng/mL. Short sleep duration was defined as total sleep time<6 hours.

RESULTS

The risk of 25(OH)D deficiency was observed in 59.5% of the sample, affecting more individuals of the female gender, obese, with African American ethnicity, and those that were smokers, sedentary and presented hypertension and diabetes. In the final logistic model adjusted for age, gender, ethnicity, obesity, smoking, hypertension, diabetes, sedentary lifestyle, seasonality and creatinine serum levels, both OSA and short sleep duration showed significant independent associations with the risk of 25(OH)D deficiency (moderate OSA: OR for 25(OH)D<30 = 2.21, 95% CI: 1.35-3.64, p<0.01; severe OSA: OR for 25(OH)D<30 = 1.78, 95% CI: 1.06-3.00, p = 0.03; short sleep duration: OR for 25(OH)D<30 = 1.61, 95% CI: 1.15-2.26, p = 0.01). After a subgroup analysis, similar results were observed only in participants ≥50 years.

CONCLUSION

OSA and short sleep duration are independently associated with the risk of 25(OH)D deficiency in an adult population. Age-related changes in vitamin D metabolism and the frequency of sleep disorders may be involved in these associations. Future studies exploring whether 25(OH)D levels may modulate OSA and sleep curtailment-related outcomes are needed.