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

Urban-rural differences in the prevalence and associated factors of sarcopenia: A systematic review and meta-analysis

BACKGROUND

Loss of muscle mass, muscle strength, and/or physical performance due to aging is known as sarcopenia. Regardless of how serious this illness is, no single diagnostic criteria have been established. Much research conducted recently has demonstrated differences between built environment characteristics (i.e., urban and rural) and the occurrence of sarcopenia; however, variations in sarcopenia prevalence in urban-rural areas around the world have been reported by fewer studies. This work sought to determine how sarcopenia prevalence varied between urban and rural areas and to explore the associated influencing factors.

METHODS

Using the pertinent MESH phrases and free words, PubMed, Web of Science, Embase, and China national knowledge infrastructure databases were scanned for core sarcopenia literature up to February 26, 2023. Observational studies involving urban-rural patients with sarcopenia published in Chinese and English, and assessing muscle mass via computed tomography, bioelectrical impedance, or dual-energy X-ray absorption techniques were considered as inclusion criteria. The meta-analysis involved analysis of the urban-rural prevalence in subgroups by diagnostic criteria, tools for assessing muscle mass and study type, as well as the factors related to urban-rural differences in the occurrence of sarcopenia. STATA version 11.0 was used to perform the statistical analysis.

RESULTS

Sixty-six articles involving 433,091 participants were included for analysis: of which 27 were analyzed for both prevalence and related factors whereas 39 were for only prevalence. The meta-analysis revealed the prevalence of sarcopenia to be 0.18 (95 % CI 0.14-0.22), with significant heterogeneity (P < 0.001; I2 = 99.9 %). Moreover, the prevalence of sarcopenia in urban group [0.16 (I2 = 99.9 %, 95 % CI 0.1-0.22)] was lower than in rural group [0.2 (I2 = 99.6 %, 95 % CI 0.16-0.25)] and urban-rural group [0.21 (I2 = 97.5 %, 95 % CI 0.16-0.25)]. Besides, the factors significantly associated with sarcopenia in urban-rural areas were age, gender, BMI, malnutrition, physical activity, and polypharmacy. There was significant heterogeneity between these factors and the association of sarcopenia.

CONCLUSIONS

Sarcopenia is associated with aspects of the built environment, and studies have revealed that sarcopenia is more common in rural than in urban populations with influencing factors including age, gender, BMI, poor nutrition, insufficient physical activity, and polypharmacy. The lack of uniform diagnostic criteria makes a robust and comprehensive assessment difficult. Therefore, the formation of certain universal and standardized diagnostic criteria will help future research on sarcopenia.

The role of interaction between vitamin D and VDR FokI gene polymorphism (rs2228570) in sleep quality of adults

To evaluate association of vitamin D with sleep quality in adults and the influence of VDR-gene polymorphism FokI (rs2228570;A > G). Cross-sectional population-based study in adults, conducted in Brazil. The outcome was sleep-quality, evaluated by the Pittsburgh Sleep Quality Index. Vitamin D was determined by indirect electrochemiluminescence and classified as deficiency (VDD), 25(OH)D < 20 ng/mL in a healthy population or 25(OH)D < 30 ng/mL for groups at risk for VDD. FokI polymorphism in the VDR-gene was genotyped by qPCR and classified as homozygous wild (FF or AA), heterozygous (Ff or AG), or homozygous mutant (ff or GG). Multivariate logistic analysis was used to estimate the association between vitamin D and FokI polymorphism with sleep-quality. In a total of 1674 individuals evaluated, 53.6% had poor-sleep-quality, 31.5% had VDD, and the genotype frequency of the FokI polymorphism was 9.9% FF, 44.6% Ff, and 45.5% ff. In multivariate analysis, individuals with VDD had 1.51 times the chance of poor-sleep-quality, and individuals with the ff genotype had 1.49 times the chance of poor-sleep-quality (OR:1.49;95%CI:1.05-2.12) when compared to individuals with the FF or Ff genotype. In the combined analysis, individuals with VDD and ff genotype had more chance of poor-sleep-quality than individuals with sufficient vitamin D and genotype Ff or FF (OR:2.19;95%CI:1.27-3.76). Our data suggest that VDD and VDR FokI gene polymorphism are associated with poor-sleep-quality, and combining the two factors increases the chance of poor-sleep-quality compared to separate groups.

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.

Associations between Vitamin D Status and Polysomnographic Parameters in Adults with Obstructive Sleep Apnea

Vitamin D deficiency (VDD) may be associated with obstructive sleep apnea (OSA) presence and is more pronounced with increasing OSA severity; however, the relationship between these two entities remains unclear. This was a cross-sectional study among 262 adults with in-hospital-attended polysomnography-diagnosed OSA and no additional major comorbidities, aiming to explore possible associations between serum 25-hydroxyvitamin D [25(OH)D] levels and polysomnographic parameters. Data on demographics, medical history, anthropometric indices, and lifestyle habits were collected at enrolment. Serum 25(OH)D was evaluated using chemiluminescence, with VDD defined as 25(OH)D < 20 ng/mL. VDD was observed in 63% of the participants. Serum 25(OH)D correlated negatively with apnea-hypopnea index and other polysomnographic indices (all p < 0.05). In logistic regression analysis, adjusting for age, sex, smoking, body mass index, physical activity, dietary vitamin D intake, and season of blood sampling, serum 25(OH)D was associated with lower odds of severe OSA [odds ratio (95% confidence interval): 0.94 (0.90-0.98)]. In the same multivariate model, VDD was associated with ~threefold higher odds of severe OSA [2.75 (1.38-5.48)]. In stratified analyses, VDD predicted OSA severity in the group of participants ≥50 y [3.54 (1.29-9.68)] and among those with body mass index ≥ 30 kg/m2 [3.38 (1.52-7.52)], but not in the younger and non-obese adults. This study provides further evidence of an inverse association between vitamin D levels and OSA severity and underscores the importance of considering vitamin D status as a potential modifiable factor in the comprehensive management of OSA.

Relationship of serum 25-hydroxyvitamin D, obesity with new-onset obstructive sleep apnea

OBJECTIVE

The prospective association between vitamin D and obstructive sleep apnea (OSA) remains uncertain. We aimed to assess the association between serum 25-hydroxyvitamin D (25(OH)D), a major circulating form of vitamin D, and new-onset OSA, and examine the modifying effect of obesity.

MATERIALS AND METHODS

This prospective cohort study included 444,975 participants from UK Biobank without prior OSA. The primary outcome was new-onset OSA.

RESULTS

During a median follow-up duration of 12.0 years, 6051 (1.4%) participants occurred new-onset OSA. Overall, there was an inverse relation of serum 25(OH)D concentrations with the risk of new-onset OSA (per SD increment, HR, 0.92; 95%CI: 0.89-0.95). In the analysis of the interactions of serum 25(OH)D with the combination of BMI (<25, 25- < 30, and ≥30 kg/m2) and waist circumference (WC) (<90 and ≥90 cm) categories on new-onset OSA, the significantly inverse association of serum 25(OH)D and new-onset OSA was mainly found in participants with both BMI ≥ 25 kg/m2 and WC ≥ 90 cm (BMI 25-30 kg/m2 and WC ≥ 90 cm: per SD increment, HR, 0.90; 95%CI: 0.84-0.95; BMI ≥ 30 kg/m2 and WC ≥ 90 cm: per SD increment, HR, 0.85; 95%CI: 0.81-0.88), but not in other four groups with BMI < 25 kg/m2 or WC < 90 cm (P -interaction = 0.004).

CONCLUSIONS

There was an inverse relation of serum 25(OH)D with the risk of new-onset OSA in participants with both BMI ≥ 25 kg/m2 and WC ≥ 90 cm. Our findings suggest the importance of maintaining a higher serum 25(OH)D concentration for primary prevention of OSA in a population with obesity.

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.

Association between vitamin D and knee osteoarthritis in Indian population: A systematic review and meta-analysis

Background

Vitamin D deficiency (VDD) has been implicated in knee osteoarthritis (KOA) development and progression. Prevalence of hypovitaminosis D and osteoporosis in KOA is widely reported in Indian population. However, there is no attempt to critically evaluate the outcome of these studies. We aimed a systematic review of these studies.

Methods

Pubmed, Google Scholar and Web of Science last updated March 2023, were searched. We reviewed eligible studies on the association between KOA and vitamin D levels in Indian and Asian population for comparison. The mean difference (MD) of vitamin D levels and odds ratio (OR) of vitamin D status were calculated. Data were interpreted by RevMan 5.4 software. The risk of bias was assessed using the Cochrane Risk of Bias tool.

Results

A total of 15 studies that involved 1503 KOA cases and 1609 controls were included. There was significantly reduced level of vitamin D in KOA (MD -8.68 ng/mL, 95%CI -12.21 to -5.15; P = <0.00001, I2 = 82 %) in Indian population. Similarly, in other Asian population significantly reduced vitamin D levels in KOA (MD 18.36 ng/mL, 95%CI -34.72 to -2.00; P = <0.00001, I2 = 100 %) was observed in KOA. VDD was found to be positively correlated with an increased risk of KOA.

Conclusion

Early diagnosis and management of VDD may provide the opportunity to delay the ongoing degenerative process of KOA and this study indicates the importance of screening VDD even in sunlight rich regions.

Associations between serum vitamin D status and the cardiometabolic profile of patients with obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) and the metabolic syndrome (MetS) frequently coexist. Low serum vitamin D has been positively associated with OSA presence and severity; however, data on its link to cardiometabolic features in patients with OSA remain scarce. We aimed to assess serum 25-hydroxyvitamin D [25(OH)D] and explore its association with cardiometabolic parameters in OSA.

METHODS

This was a cross-sectional study among 262 patients (49 ± 9 years old, 73% men) with polysomnography-diagnosed OSA. Participants were evaluated in terms of anthropometric indices, lifestyle habits, blood pressure, biochemical, plasma inflammatory and urinary oxidative stress markers, and the presence of MetS. Serum 25(OH)D was assessed by chemiluminescence, and vitamin D deficiency (VDD) was defined as 25(OH)D < 20 ng/mL.

RESULTS

Median (1st, 3rd quartile) serum 25(OH)D levels were 17.7 (13.4, 22.9) ng/mL and 63% of participants had VDD. Serum 25(OH)D correlated negatively with body mass index (BMI), homeostasis model of assessment of insulin resistance (HOMA-IR), total cholesterol, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein (hsCRP), and urinary oxidized guanine species (oxG), and positively with high-density lipoprotein cholesterol (all P < 0.050). In logistic regression analysis, serum 25(OH)D was associated with lower odds of MetS [odds ratio (95% confidence interval): 0.94 (0.90-0.98)], after adjustment for age, sex, season of blood sampling, Mediterranean diet score, physical activity, smoking, apnea-hypopnea index, HOMA-IR, hsCRP, and oxG. In the same multivariate model, VDD was associated with ~ twofold greater odds of MetS [2.39 (1.15, 4.97)].

CONCLUSION

VDD is highly prevalent and is associated with a detrimental cardiometabolic profile among patients with OSA.

Sleep Patterns Modify the Association between Vitamin D Status and Coronary Heart Disease: Results from NHANES 2005-2008

BACKGROUND

Although an increased risk of coronary heart disease (CHD) has been reported in individuals with low vitamin D status, this remains controversial. Growing evidence suggests that sleep behaviors may influence vitamin D endocrine functions.

OBJECTIVES

We explored the association between serum 25-hydroxyvitamin D [[25(OH)D] concentrations and CHD and whether sleep behaviors modify this relationship.

METHODS

A cross-sectional analysis of 7511 adults aged ≥20 y in 2005-2008 National Health and Nutrition Examination Survey (NHANES) that included serum 25(OH)D concentrations and provided information on sleep behaviors and history of CHD was performed. Logistic regression models were used to assess the association between serum 25(OH)D concentrations and CHD, whereas stratified analyses and multiplicative interaction tests were used to evaluate the modification effect of overall sleep patterns and each sleep factor on this relationship. The overall sleep patterns integrated 4 sleep behaviors (sleep duration, snoring, insomnia, and daytime sleepiness) in the form of healthy sleep score.

RESULTS

Serum 25(OH)D concentrations were inversely associated with risk of CHD (P < 0.01). Hypovitaminosis D [serum 25(OH)D <50nmol/L] was associated with a 71% increased risk of CHD (OR: 1.71; 95% CI: 1.28, 2.28; P < 0.01) compared with that in participants with sufficient vitamin D [serum 25(OH)D ≥75nmol/L], and the association was more evident and stable among participants with poor sleep patterns (P-interaction < 0.01). Among the individual sleep behaviors, sleep duration had the strongest interaction with 25(OH)D (P-interaction < 0.05). The association between serum 25(OH)D concentrations and risk of CHD was more pronounced in participants with sleep duration <7 h/d or >8 h/d compared with those with sleep duration 7-8 h/d.

CONCLUSIONS

These findings suggest that the influence of lifestyle-related behavioral risk factors, such as sleep behaviors (especially sleep duration), need to be considered when evaluating the association between serum 25(OH)D concentrations and CHD as well as the clinical benefits of vitamin D supplementation.

Vitamin D Deficit as Inducer of Adenotonsillar Hypertrophy in Children with Obstructive Sleep Apnea-A Prospective Case-Control Study

(1) Objective: This prospective case-control study aimed to assess the level of serum vitamin D comparing pediatric non-allergic patients with obstructive sleep apnea (OSA) and healthy controls. (2) Methods: The period of the enrollment was from November 2021 to February 2022. Children with uncomplicated OSA caused by adenotonsillar hypertrophy (ATH) were recruited. Allergy was excluded by skin prick test (SPT), and the determination of serum IgE level using ELISA test. Plasma concentration of 25-hydroxy vitamin D (25-OHD) was quantitatively determined; then, the vitamin D concentration in patients was compared with healthy controls matched for sex, age, ethnicity, and characteristics. (3) Results: Plasma 25-OHD levels were significantly lower in patients than in healthy subjects (mean 17 ng/mL, 6.27 DS, range 6-30.7 ng/mL, vs. mean 22 ng/mL, 9.45 DS, range 7-41.2 ng/ ml; p < 0.0005). The prevalence of children with vitamin D deficiency was significantly higher in the ATH group than controls. The plasma 25-OHD level did not change following the ATH clinical presentation (III or IV grade according to the Brodsky scale), while the different categories of 25-OHD status (insufficiency, deficiency, and adequacy) in the ATH group were statistically significantly different (p < 0.001) from healthy controls. (4) Conclusions: This study identified statistically significant differences between the ATH group and control regarding the plasma concentration of vitamin D; this data, despite not being directly linkable to the lymphoid tissue hypertrophy (p-value not significant), might suggest a negative effect of vitamin D deficit on the immune system.

Sleep patterns modify the association of 25(OH)D with poor cardiovascular health in pregnant women

BACKGROUND

The relationship between vitamin D status and gestational cardiovascular health (CVH) is inconsistent in previous studies. Emerging evidence shows that sleep behaviors are related to vitamin D metabolism. However, no studies evaluate the interaction of vitamin D and sleep behaviors on gestational CVH.

OBJECTIVE

We aimed to estimate the relationship between 25-hydroxyvitamin D [25(OH)D] concentrations and gestational CVH, and whether the relationship was modified by sleep behaviors.

METHODS

The data of this study was from a multicenter birth cohort study. A total of 9,209 pregnant women at 16-23 weeks of gestation were included. 25(OH)D concentrations were measured from collected blood. Sleep patterns consisted of major sleep behaviors including duration, chronotype, insomnia, snoring, and excessive daytime sleepiness. Data on poor CVH was based on four "clinical" CVH metrics, including body mass index, blood pressure, total cholesterol, and glucose levels.

RESULTS

The proportion of women with poor CVH was 25.0%. The relative risk (RR) (95%CI) of poor CVH was 0.67 (0.58-0.76) in women with 25(OH)D ≥ 50 nmol/L after multivariate adjustments. Lower 25(OH)D concentrations were significantly associated with poor CVH. Such association was also evident in subgroups analysis. We found a significant interaction of 25(OH)D (P for interaction = 0.01) with sleep patterns on the risk of poor CVH. A negative dose-response relation was observed between 25(OH)D concentrations and poor CVH risk in healthy or intermediate sleep, not poor sleep. 25(OH)D concentrations were lower and the risk of poor CVH was higher in pregnant women with poor sleep patterns (P < 0.05).

CONCLUSION

Our study suggests that sleep patterns modify the association of 25(OH)D concentrations with the CVH among pregnant women.

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.

The effect of vitamin D on sleep quality: A systematic review and meta-analysis

Background: Poor sleep quality is a common problem in the general population that affects the quality of life of individuals. Aim: This systematic review aimed to determine the effect of vitamin D on sleep quality (primary outcome) and side effects (secondary outcome). Methods: A systematic search was performed using Cochrane Library, PubMed, Embase, Web of Sciences, Scopus, Google Scholar, SID, and Magiran databases with no limit at the time of publication. Cochrane collaboration instrument was used to evaluate the quality of the included studies. RevMan software was used for meta-analysis. Mean Difference was calculated due to the same sleep quality measurement tools in all studies. Heterogeneity of studies was assessed using I-squared (I2). Due to high heterogeneity (I2 > 75%), Random Effect was used instead of Fixed Effect. Results: Out of a total of 1637 titles and abstracts found, after removing duplicate items (23 items), 1596 items were removed due to irrelevance and lack of inclusion criteria. 18 articles were fully studied due to insufficient abstract information and finally, 5 articles were entered into systematic review and meta-analysis. The results of the meta-analysis showed that the use of vitamin D supplementation significantly improves sleep quality (MD: -1.32; 95%CI: -2.55 to -0.09; P = 0.04). Conclusions: Also, according to the findings of this study, receiving vitamin D supplementation did not cause any side effects. According to the results of this review study, sleep quality in people receiving vitamin D significantly improved compared to the control group.

An umbrella review of systematic reviews and meta-analyses of observational investigations of obstructive sleep apnea and health outcomes

Purpose

The previous analysis of systematic reviews and meta-analyses have illustrated that obstructive sleep apnea (OSA) is correlated with multiple health outcomes. In the present research, our main aim was to execute an umbrella review to assess the available evidence for the associations between OSA and health outcomes.

Methods

Herein, a meta-analysis of previous observational investigations that have reported associations between OSA and health outcomes in all human populations and settings was performed. We used these studies to execute an umbrella review of available meta-analyses and systematic reviews.

Results

Sixty-six articles comprising 136 unique outcomes were enrolled in this analysis. Of the 136 unique outcomes, 111 unique outcomes had significant associations (p < 0.05). Only 7 outcomes (coronary revascularization after PCI, postoperative respiratory failure, steatosis, alaninetrans aminase (ALT) elevation, metabolic syndrome (MS), psoriasis, and Parkinson’s disease) had a high quality of evidence. Twenty-four outcomes had a moderate quality of evidence, and the remaining 80 outcomes had a weak quality of evidence. Sixty-nine outcomes exhibited significant heterogeneity. Twenty-five outcomes exhibited publication bias. Sixty-three (95%) studies showed critically low methodological quality.

Conclusion

Among the 66 meta-analyses exploring 136 unique outcomes, only 7 statistically significant outcomes were rated as high quality of evidence. OSA may correlate with an increased risk of coronary revascularization after PCI, postoperative respiratory failure, steatosis, ALT elevation, MS, psoriasis, and Parkinson’s disease.

Polymorphisms in vitamin D receptor and parathyroid hormone genes in the development and progression of obstructive sleep apnea in Asian Indians

OBJECTIVES

Vitamin D plays a role in multiple aspects of human physiology, and vitamin D receptor (VDR) and parathyroid hormone (PTH) genes are associated with obesity. No data are available, to our knowledge, on the possible relationship between obstructive sleep apnea (OSA) and genetic variations of VDR and PTH genes. This study aimed to assess the significance of vitamin D and PTH, as well as VDR, and PTH gene polymorphisms with body composition and biochemical investigations in Asian Indians with and without OSA.

METHODS

In this study, 120 obese subjects with OSA, 110 obese subjects without OSA, and 70 nonobese subjects without OSA were recruited. Clinical, body composition, anthropometry, and biochemical investigations, as well as a full overnight polysomnography were measured. Genotyping related to VDR (BsmI, ApaI FokI, and TaqI) and PTH (BstBI and DraII) genes were investigated with a quantitative real-time polymerase chain reaction.

RESULTS

The mean values of the lower serum 25(OH) D (12.9 ± 3.8; P = 0.0001) and higher serum PTH levels (61.9 ± 12.5; P = 0.0001) were observed in obese subjects with OSA. There was an indirect correlation between serum 25(OH) D levels and OSA severity (P < 0.001). VDR (BsmI and FokI) and PTH (BstBI and DraII) genes were significantly associated with OSA (P < 0.05). Analyses of VDR haplotype combination variants (BBFFAATt [odds ratio: 3.45; 95% confidence interval, 0.986-4.567] and BbFFAaTt [odds ratio: 2.86; 95% confidence interval, 1.345-4.981) were more frequent in obese subjects with OSA (P = 0.001). The BBDD and bbDd haplotypes of the PTH gene seems to be a predisposing factor for OSA (P < 0.05).

CONCLUSIONS

Lower serum 25(OH) D levels were significantly observed in patients with OSA and correlate with disease severity. Also, VDR and PTH mutations were found to be highly related with OSA in Asian Indians.