Sleep disordered breathing and metabolic comorbidities across sex and menopausal status in East Asians: the Nagahama Study

Analysis of the relationship between comorbid obstructive sleep apnea and clinical outcomes in patients with asthma in Japan

BACKGROUND

Asthma and obstructive sleep apnea (OSA) are prevalent chronic respiratory disorders, which often coexist and interact with each other. Obesity is an important risk factor shared by them. The rate of obesity is lower in Japan versus Western countries. Hence, the co-existence of asthma and OSA has not been investigated in Japan.

METHODS

Ninety-seven outpatients with asthma were recruited. Patients wore a portable monitor for sleep study. Background data, pulmonary function, blood tests, and patient-reported outcomes including gastroesophageal reflux disease, sleepiness, sleep quality, asthma control, cough and respiratory symptoms, and health status, were assessed.

RESULTS

Of the patients, 19 (19.6 %), 40 (41.2 %), 24 (24.7 %), and 14 (14.4 %) were classified into non-, mild, moderate, and severe OSA groups. Non-OSA patients were younger than those in other groups (p < 0.05). The BMI of patients with moderate and severe OSA, was higher than that of non-OSA patients (p < 0.05). Pulmonary function, FeNO, serum IgE, and the number of peripheral eosinophils were not significantly different between groups. Nonetheless, compared with the other groups, treatment step was the highest, and the Asthma Control Test, Leicester Cough Questionnaire, COPD Assessment Test, and Asthma Health Questionnaire-33 yielded worst scores in the severe OSA group, and predicted the severe OSA after adjustment by BMI.

CONCLUSIONS

Moderate and severe OSA are highly prevalent among patients with asthma in Japan. Pulmonary function did not differ between groups. However, patients with asthma and severe OSA were linked to more asthma treatment, worse asthma control, more symptoms and cough, and worse health status.

Obstructive Sleep Apnea and Oxygenation in Very Old Adults: A Propensity-Score Match Study

OBJECTIVES

The prevalence of obstructive sleep apnea (OSA) escalates with advancing age. Although the apnea-hypopnea index (AHI) is the standard measure for assessing OSA severity, it does not account for additional oximetric parameters that may influence disease progression in older adults. This study aimed to evaluate disparities in respiratory polygraphy/polysomnography parameters among patients with OSA, stratified by age and sex.

DESIGN

Retrospective propensity score-matched study.

SETTING AND PARTICIPANTS

Sleep unit of a university hospital; 11,747 participants, 210 aged 80 years or older.

METHODS

Propensity score matching was used to establish 4 age cohorts, with the 210 oldest adults serving as the reference group. Primary outcome variables included the total sleep time with oxygen saturation (SaO2) below 90% (T90), average SaO2, minimum SaO2, and AHI. The association between T90 and AHI, as well as the severity of OSA, was assessed across the 4 age categories.

RESULTS

Despite comparable AHI scores, the oldest patients with OSA exhibited the highest T90 and the lowest SaO2 levels compared to younger counterparts. The proportion of patients with severe OSA and T90 in the highest quartile increased with age: 12.5% in young adults, 14.8% in adults, 21.7% in the old, and 34% in the very old participants (P < .001). old and very old patients had a greater likelihood of being in the most severe OSA category compared to the younger ones, with odds ratios (OR) 2.57 (95% CI 1.42-4.65) and 5.52 (95% CI 3.06-9.97), respectively. These patterns were more pronounced in women of advanced age, indicating a sex-specific variation in disease severity with increasing age.

CONCLUSIONS AND IMPLICATIONS

Old patients with OSA, particularly women, demonstrate elevated T90 and reduced SaO2 levels, irrespective of AHI, indicating a hypoxemia increased risk. The diagnostic criteria, management, and outcomes for OSA may require adaptations to address the unique needs of very old populations.

Sleep-related breathing disorder in a Japanese occupational population and its association with hypertension-stratified analysis by obesity status

Sleep-related breathing disorder (SRBD) causes hypertension, and obesity has been highly associated with SRBD, which has become a serious health problem in young and middle-aged Japanese males. However, the relation between SRBD and hypertension considering the effects of obesity remains unknown. In this cross-sectional study, we examined the relationship between SRBD and hypertension, with consideration for the effects of obesity, in Japanese occupational population. Using 3% oxygen desaturation index (3%ODI) obtained by simplified polysomnography (PSG), participants were classified into low (0 ≤ 3%ODI < 5), medium (5 ≤ 3%ODI < 15), and high (15 ≤ 3%ODI) 3%ODI groups. We excluded employees who had not undergone medical examination with simplified PSG in the same year from 2012 to 2018. Logistic regression analysis was performed to calculate odds ratios for having hypertension according to 3%ODI levels. In total, 2532 employees were included. Among them, 25% and 4% were categorized into the medium and high 3%ODI groups, respectively. The odds ratio for hypertension increased significantly with higher 3%ODI levels after adjustment for age, sex, alcohol drinking status and smoking status (p for trend < 0.0001). However, further adjustment for obesity status (body mass index ≥ 25 kg/m2) attenuated the associations. When we performed the stratified analysis by obesity status, the odds ratio for hypertension increased significantly with higher 3%ODI only for non-obese individuals, with significant interaction (p for interaction = 0.014). Higher 3%ODI was significantly associated with higher prevalence of hypertension especially in non-obese participants, suggesting the importance of vigilance for the presence of SRBD even in non-obese individuals. We investigated the association between SRBD and hypertension considering the effects of obesity, which would suggest the need to keep in mind the presence of SRBD even in non-obese individuals.

Sleep status of older adults with sleep apnoea syndrome may vary by body mass index

Obesity and ageing are the most important risk factors for sleep apnoea syndrome (SAS); however, the role of body mass index (BMI) on sleep status in healthy older adults is unclear. To explore sleep parameters according to BMI among active older adults, we cross-sectionally examined the relationship between sleep-related parameters and BMI in 32 Japanese adults aged from 83 to 95 years without long-term care who were unaware of having SAS. Correlation and linear regression analyses were performed. Moderate or severe SAS prevalence was high in both those with low (68.8%) and high (68.8%) BMI. A higher increase in apnoea-hypopnoea index (AHI) was negatively correlated with sleep depth in the high-BMI group. In the low-BMI group, the number of awakenings and age were positively correlated with AHI. Older adults may have SAS regardless of their BMI, and the sleep status of patients with SAS may vary by BMI.

Associations between Nocturnal Hypoxemia and Retinal Nerve Fiber Layer Thinning: The Nagahama Study

Rationale: There have been meta-analyses that showed reduced retinal nerve fiber layer (RNFL) thickness, which is a surrogate marker of glaucoma, in patients with obstructive sleep apnea (OSA). However, the sample sizes in these reports were small (<300), and the mechanism of RNFL thinning in patients with OSA was not revealed.Objectives: To investigate the relationship of RNFL thickness with nocturnal hypoxemia or hypoxemic burden in a large-scale study.Methods: In this epidemiological study, 8,309 community residents were enrolled. The actigraphy-modified 3% oxygen desaturation index (acti-ODI3%) and cumulative percentage of sleep time with oxygen saturation <90% (acti-CT90) modified by objective sleep duration using actigraphy were measured. The hypoxemic burden is shown as acti-CT90. Circumpapillary RNFL thickness was determined using optical coherence tomography.Results: Multivariable logistic analysis models revealed that an increase in acti-CT90 was significantly associated with mean RNFL thinning after adjusting for several factors in participants without glaucoma diagnosed or treated previously (β = -0.037; P = 0.009). There were significant differences in mean RNFL thickness among participants stratified according to acti-CT90 (>1.5 vs. ⩽1.5; P = 0.04). Although acti-ODI3% was significantly associated with acti-CT90 (β = 0.72; P < 0.0001), acti-ODI3% was not significantly associated with mean RNFL thickness in the multivariable logistic analysis (β = -0.011; P = 0.48). In addition, acti-CT90 was significantly associated with mean RNFL thickness both in the elderly (⩾60 yr; β = -0.058; P = 0.002) and nonelderly (<60 yr; β = -0.054; P = 0.007).Conclusions: Acti-CT90, but not acti-ODI3%, was associated with mean RNFL thinning in participants irrespective of age in the elderly or nonelderly. Further prospective studies are required to investigate whether the prevention of hypoxic burden, which was shown as acti-CT90 in this study, is favorable for RNFL thinning.

Increased blood eosinophils and airflow obstruction as new-onset asthma predictors in the elderly: The Nagahama study

BACKGROUND

Asthma in the elderly needs more attention in an aging society. However, it is likely to remain underdiagnosed and undertreated. This study aimed to clarify clinical characteristics of new-onset asthma in the elderly, describing the prevalence, predictive factors, and comorbidities after asthma diagnosis of new-onset asthma in the elderly in the general population.

METHODS

This community-based prospective cohort study enrolled 9804 generally healthy participants (30-74 years old) in Nagahama City, and conducted a follow-up assessment after 5 years. Elderly participants were those aged ≥65 years at baseline. Patients with new-onset asthma were defined as participants without asthma at baseline assessment and with asthma at the follow-up assessment.

RESULTS

Among the 7948 participants analyzed in this study, 28 (1.4%) elderly and 130 (2.2%) non-elderly had new-onset asthma. Multiple logistic regression analysis revealed low forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) and high blood eosinophil counts at baseline as predicting factors for new-onset asthma in the elderly. Additionally, subsequent incidence of new-onset asthma was higher in elderly participants with both predictors (high blood eosinophil counts and low FEV1/FVC at baseline) than those with none or one of the predictors before asthma diagnosis. Lastly, elderly patients with new-onset asthma had more frequent comorbidity of moderate to severe sleep disordered breathing than those non-elderly.

CONCLUSIONS

Eosinophilic inflammation and airflow obstruction may predict subsequent new-onset asthma after the age of 65 years. Revealing the characteristics of new-onset asthma in the elderly can aid in the prevention of underdiagnosed asthma.

Associations between Sleep-Disordered Breathing and Serum Uric Acid and Their Sex Differences: The Nagahama Study

Sleep-disordered breathing (SDB) is often accompanied by noncommunicable diseases (NCDs), including gout. However, the association between serum uric acid (sUA) levels and NCDs is complicated in patients with SDB. We aimed to clarify this issue utilizing large-scale epidemiological data. This community-based study included 9850 inhabitants. SDB and its severity were assessed by a 3% oxygen desaturation index (3% ODI) corrected for sleep duration using wrist actigraphy. The associations between sUA and moderate to severe SDB (MS-SDB) and sUA and NCDs in patients with MS-SDB were analyzed. A total of 7895 subjects were eligible. In females, the prevalence of MS-SDB increased according to an elevation in sUA levels even after adjusting for confounders, and sUA ≥ 5 mg/dL was the threshold. These were not found in males. There was a positive interaction between sUA ≥ 5 mg/dL and female sex for MS-SDB. In females with MS-SDB, the prevalence of diabetes mellitus (DM) increased according to an elevation in sUA levels, and those with sUA ≥ 5 mg/dL showed a higher prevalence of DM than their counterparts. There is a clear correlation between sUA levels and the severity of SDB, and elevated sUA poses a risk for DM in females with MS-SDB.

Hyperfructosemia in sleep disordered breathing: metabolome analysis of Nagahama study

Sleep disordered breathing (SDB), mainly obstructive sleep apnea (OSA), constitutes a major health problem due to the large number of patients. Intermittent hypoxia caused by SDB induces alterations in metabolic function. Nevertheless, metabolites characteristic for SDB are largely unknown. In this study, we performed gas chromatography-mass spectrometry-based targeted metabolome analysis using data from The Nagahama Study (n = 6373). SDB-related metabolites were defined based on their variable importance score in orthogonal partial least squares discriminant analysis and fold changes in normalized peak-intensity levels between moderate-severe SDB patients and participants without SDB. We identified 20 metabolites as SDB-related, and interestingly, these metabolites were frequently included in pathways related to fructose. Multivariate analysis revealed that moderate-severe SDB was a significant factor for increased plasma fructose levels (β = 0.210, P = 0.006, generalized linear model) even after the adjustment of confounding factors. We further investigated changes in plasma fructose levels after continuous positive airway pressure (CPAP) treatment using samples from patients with OSA (n = 60) diagnosed by polysomnography at Kyoto University Hospital, and found that patients with marked hypoxemia exhibited prominent hyperfructosemia and their plasma fructose levels lowered after CPAP treatment. These data suggest that hyperfructosemia is the abnormality characteristic to SDB, which can be reduced by CPAP treatment.

Sleep-related factors associated with masked hypertension: the Nagahama study

OBJECTIVES

Masked hypertension, which is characterized by out-of-office hypertension but normal office blood pressure, is a risk factor for cardiovascular disease. However, the factors that contribute to masked hypertension are unclear. We aimed to determine the involvement of sleep-related characteristics in masked hypertension.

METHODS

The study included 3844 normotensive (systolic/diastolic blood pressure < 140/90 mmHg) community residents with no antihypertensive drug use at baseline (mean age 54.3 years). Home morning and evening blood pressure, oxygen desaturation during sleep (pulse oximetry), and sleep efficiency (actigraphy) were measured for 1 week. The number of nocturnal urinations during this period was obtained using a sleep diary.

RESULTS

Masked hypertension (mean morning and evening blood pressure ≥135/85 mmHg) was detected in 11.7% of study participants, and 79.0% of the participants with masked hypertension had sleep hypertension (≥120/70 mmHg). Multinominal logistic regression analysis identified different factors involved in masked hypertension with and without sleep hypertension; factors for masked hypertension with sleep hypertension included the frequency of at least 3% oxygen desaturation (coefficient = 0.038, P  = 0.001), nocturia (coefficient = 0.607, P  < 0.001), and carotid intima-media thickness (coefficient = 3.592, P  < 0.001). Only carotid intima-media thickness and measurement season were associated with masked hypertension without sleep hypertension. Low sleep efficiency was associated with isolated sleep hypertension but not masked hypertension.

CONCLUSION

Sleep-related factors associated with masked hypertension differed depending on the presence of sleep hypertension. Sleep-disordered breathing and nocturnal urination frequency may help identify individuals who need home blood pressure monitoring.

Sleep disordered breathing and haemoglobin A1c levels within or over normal range and ageing or sex differences: the Nagahama study

Recently an association between blood glucose dysregulation and sleep disruption was suggested. The association between sleep disordered breathing, most of which is due to obstructive sleep apnea (OSA) in the general population, and diabetic severity, as well as the impact of antidiabetic treatment, remains unclear. This study aimed to investigate these associations as well as age and sex differences. This cross-sectional study evaluated 7,680 community participants as the main cohort (population-based cohort). OSA was assessed by the 3% oxygen desaturation index from pulse oximetry, which was corrected for sleep duration obtained by wrist actigraphy. For arguing the limitations for using pulse oximetry, 597 hospitalised patients, who were assessed by the apnea-hypopnea index from attended polysomnography, were also evaluated as the validation cohort (hospital-based cohort). Moderate-to-severe OSA was more prevalent as haemoglobin A1c (HbA1c) levels increased (<5.6%/5.6%-<6.5%/6.5%-<7.5%/≥7.5%, respectively) in both cohorts (p < 0.001), but only in those without antidiabetic treatment. The HbA1c level was an independent factor for moderate-to-severe OSA (population-based cohort, odds ratio [OR] 1.26, 95% confidence interval [CI] 1.10-1.45; hospital-based cohort, OR 1.69, 95% CI 1.22-2.33, per 1% increase). These associations were more prominent in the middle-aged (aged <60 years) than in the elderly (aged ≥60 years) and in women than in men in both cohorts. The prevalence of moderate-to-severe OSA in patients with antidiabetic treatment in the hospital-based cohort was ≥75% regardless of HbA1c levels. In conclusion, an association between the prevalence of OSA and HbA1c level even within or over the normal range was found only in patients without antidiabetic treatment and was more prominent in the middle-aged and in women.

Super-multifactorial survey YHAB revealed high prevalence of sleep apnoea syndrome in unaware older adults and potential combinatorial factors for its initial screening

Study Objectives: Aging is a risk factor for sleep apnoea syndrome (SAS), which is associated with lower quality of life and sudden mortality. However, SAS is often overlooked in older adults without suspicions. Therefore, this study aimed to evaluate SAS incidence and 48 other general factors in older adults. Methods: This cross-sectional study included all non-caregiver-certified, healthy individuals (N = 32) who survived during the long-term cohort study and agreed to participate in apnoea-hypopnoea index (AHI) measurement (aged 83-95 years). AHI and 48 other general factors were evaluated, and simple linear regression analysis was used to identify potential AHI-related factors. Stepwise evaluation was further performed using multiple linear regression analyses. Results: Although no individuals were previously diagnosed with SAS, 30 (93.75%) participants had some degree of SAS (AHI > 5/h), and 22 (68.75%) had severe or moderate SAS (AHI > 15/h). Compared with typical single risk factors represented by body mass index, combining daily steps and other factors improved the fit to the multiple linear regression. Combining daily steps and body mass index improved the fit for males and combining daily steps and red blood cell count improved the fit for females. Conclusion: SAS was highly prevalent in unaware healthy Japanese older adults; combinations of daily steps and body mass index, and daily steps and red blood cell count may predict AHI in such individuals without the need for a specific AHI test.

A New Berlin Questionnaire Simplified by Machine Learning Techniques in a Population of Italian Healthcare Workers to Highlight the Suspicion of Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) syndrome is a condition characterized by the presence of repeated complete or partial collapse of the upper airways during sleep associated with episodes of intermittent hypoxia, leading to fragmentation of sleep, sympathetic nervous system activation, and oxidative stress. To date, one of the major aims of research is to find out a simplified non-invasive screening system for this still underdiagnosed disease. The Berlin questionnaire (BQ) is the most widely used questionnaire for OSA and is a beneficial screening tool devised to select subjects with a high likelihood of having OSA. We administered the original ten-question Berlin questionnaire, enriched with a set of questions purposely prepared by our team and completing the socio-demographic, clinical, and anamnestic picture, to a sample of Italian professional nurses in order to investigate the possible impact of OSA disease on healthcare systems. According to the Berlin questionnaire, respondents were categorized as high-risk and low-risk of having OSA. For both risk groups, baseline characteristics, work information, clinical factors, and symptoms were assessed. Anthropometric data, work information, health status, and symptoms were significantly different between OSA high-risk and low-risk groups. Through supervised feature selection and Machine Learning, we also reduced the original BQ to a very limited set of items which seem capable of reproducing the outcome of the full BQ: this reduced group of questions may be useful to determine the risk of sleep apnea in screening cases where questionnaire compilation time must be kept as short as possible.

A portrait of obstructive sleep apnea risk factors in 27,210 middle-aged and older adults in the Canadian Longitudinal Study on Aging

Determining the prevalence and characteristics of individuals susceptible to present with obstructive sleep apnea (OSA) is essential for developing targeted and efficient prevention and screening strategies. We included 27,210 participants aged ≥45 years old (50.3% women) from the Canadian Longitudinal Study on Aging. Using the STOP questionnaire combined to the percentage of body fat (%BF), we estimated the prevalence of individuals at high-risk for OSA in a sex and age-specific manner, and tested the relation with comorbidities, menopause and systemic inflammation. The prevalence was 17.5%, and was lower in women (13.1%) than in men (21.9%). A high level of high-sensitivity C-reactive protein was the strongest factor associated with OSA risk and this association was 1.3-2.3 times higher in women than in men. OSA risk increased with age, cardiovascular diseases, diabetes mellitus, anxio-depressive symptoms, asthma and arthritis. In women, post-menopausal status was associated with a high OSA risk. Nearly 1 adult out of 5 older than 45 is at risk for OSA in Canada. Comorbidities, menopause and systemic inflammation, more than age, explain increased OSA prevalence. Considering this high prevalence and associations with medical and mental comorbidities, health care practitioners should incorporate systematic OSA screening in their clinical procedures.

Differences between subjective and objective sleep duration according to actual sleep duration and sleep-disordered breathing: the Nagahama Study

STUDY OBJECTIVES

Since subjective sleep duration (SSD) is considered to be longer than objective sleep duration (OSD), results of SSD minus OSD (SSD-OSD) might always be thought to be positive. Some recent reports showed different results, but exact results have not been obtained. The difference between SSD and OSD may change according to OSD. We investigated this difference and its association with sleep-disordered breathing (SDB) or nonrestorative sleep.

METHODS

This cross-sectional study evaluated 6,908 community residents in Nagahama, Japan. SSD was determined by self-administered questionnaire. OSD was measured by wrist actigraphy and sleep diary. SDB was assessed according to the 3% oxygen desaturation index adjusted for OSD.

RESULTS

Worthy of notice was that SSD was shorter than OSD for those with SSD longer than 6.98 hours in all participants, 7.36 hours in males, and 6.80 hours in females. However, SSD was longer than OSD (mean ± SD: 6.49 ± 1.07 vs 6.01 ± 0.96; P < .001) overall, as SSD is considered to be longer than OSD. In patients with SDB, the difference between SSD-OSD was greater when OSD was shorter. The difference also depended on SDB severity. The degree of positivity between OSD and SSD was a significant factor in nonrestorative sleep (odds ratio: 2.691; P < .001).

CONCLUSIONS

When OSD was slightly less than 7 (6.98) hours, participants reported or perceived SSD > OSD. When OSD was > 6.98 hours, participants reported or perceived SSD < OSD. Patients with SDB reported longer SSD than OSD according to severity of SDB. Evaluating SSD, OSD, and their differences may be useful for managing sleep disturbances, including nonrestorative sleep.

CITATION

Takahashi N, Matsumoto T, Nakatsuka Y, et al. Differences between subjective and objective sleep duration according to actual sleep duration and sleep-disordered breathing: the Nagahama Study. J Clin Sleep Med. 2022;18(3):851-859.

Menopause and sleep disorders

Women are likely to suffer from sleep disorders more in comparison to men during menopause and with advancing age. The incidence of sleep disorders ranges from 16% to 47% at peri-menopause and 35%–60% at postmenopause. Insomnia with or without associated anxiety or low lying depression and Mood disorder is most common associated manifestations. Sleep disorders and insomnia largely remain a clinical diagnosis based on the subjective complaints of patients. Benzodiazepines remain the mainstay of the treatment in majority of the sleep disorders including chronic or acute insomnia. Treatment of associated anxiety, depression, or psychosis is most important. Tricyclic antidepressant, Selective Serotonin Reuptake Inhibitors (SSRI), Melatonin, Duloxetine, Fluoxetine, Imipramine, Nortriptyline or Amitriptyline and other drugs such as Eszopiclone, Escitalopram, Gabapentin, Quiteiapine, Citalopram, Mirtazapine followed by long-acting Melatonin and Ramelteon, also are very useful for the management of various sleep disorders. Hormone replacement therapy presently lacks concrete evidence to be used in menopausal women for sleep disorder. Sleep hygiene practices, self-hypnosis, meditation, and exercise play a very important role.

Association of Sleep Disordered Breathing and Blood Pressure with Albuminuria: The Nagahama Study

RATIONALE

Although sleep disordered breathing (SDB) may increase urinary albumin excretion (UAE) by raising nocturnal blood pressure (BP) in addition to diurnal BP, the correlation has not been investigated in a general population.

OBJECTIVES

To evaluate the relationships among UAE, SDB and BP during sleep in a large population cohort.

METHODS

Among 9,850 community residents, UAE was assessed by the urinary albumin creatinine ratio (UACR) in spot urine. Sleep duration and SDB were evaluated by a wearable actigraph and pulse oximeter, respectively. We calculated the actigraphy-modified 3% oxygen desaturation index (Acti-3%ODI) by correcting the time measured by pulse oximetry according to sleep duration obtained by actigraphy. Further, participants were instructed to measure morning and sleep BP at home by a timer-equipped oscillometric device.

RESULTS

Measurements of sleep parameters, UAE and office BP were completed in 6,568 participants. The multivariate analysis that included confounders showed a significant association of Acti-3%ODI with UACR. (β=0.06, p<0.001) Further, a positive interaction between office systolic BP (SBP) and Acti-3%ODI for UACR was found. (β=0.06, p<0.001) Among the 6,568 persons enrolled in the analysis, 5,313 completed measurements of BP at home. In this cohort, the association of Acti-3%ODI with UACR remained significant (β=0.06, p<0.001) even after morning and sleep SBP were included in the analysis. Further, mediation analysis revealed that 28.3% (95% confidence interval: 14.9-41.7%, p<0.001) of the association of Acti-3%ODI with UACR was explained by the mediation of morning and sleep SBP metrics.

CONCLUSIONS

SDB and office SBP were independently and synergistically associated with UAE, which is considered as a risk factor for chronic kidney disease and cardiovascular events. SDB may raise UAE not only by increasing BP but involving other pathologic pathways.

Markers of cardiovascular disease risk in sleep-disordered breathing with or without comorbidities: the Nagahama Study

STUDY OBJECTIVES

Whether the association between sleep-disordered breathing (SDB) and cardiovascular disease (CVD) is independent of comorbid risk factors for CVD is controversial. The objective of this study is to elucidate whether the association between SDB severity and the surrogate markers of CVD evets differs in relation to the number of comorbidities.

METHODS

This cross-sectional study included 7731 participants. Severity of SDB was determined by the oxygen desaturation index adjusted by actigraph-measured objective sleep time. Participants were stratified according to SDB severity and the number of comorbidities (hypertension, diabetes, dyslipidemia and obesity), and the associations between the maximum value of intima-media thickness of the common carotid artery (CCA-IMT-max), brachial-ankle pulse wave velocity (baPWV) and cardio-ankle vascular index (CAVI) were evaluated.

RESULTS

Among participants with no risk factor, CCA-IMT-max increased according to SDB severity (n = 1022, P <0.0001). Even after the matching of background, the median CCA-IMT-max value was 14% higher in moderate-severe SDB cases than those without SDB (n=45 in each group, P=0.020). The difference was not significant for baPWV and CAVI. On the other hand, a significant difference in CCA-IMT-max was not found in those with multiple comorbidities. Consistently, multiple regression analysis revealed an independent association between CCA-IMT-max and moderate-severe SDB for all study participants (β: 0.0222 (95% confidence interval: 0.0039-0.0405), P=0.017), but the association was not significant for stratified participants with multiple comorbidities.

CONCLUSIONS

SDB severity is associated with the CCA-IMT-max level, but the independent association becomes weaker for those with multiple comorbidities.

Obstructive Sleep Apnea and Cognitive Decline: A Review of Potential Vulnerability and Protective Factors

Around 40% of dementia risk is attributable to modifiable risk factors such as physical inactivity, hypertension, diabetes and obesity. Recently, sleep disorders, including obstructive sleep apnea (OSA), have also been considered among these factors. However, despite several epidemiological studies investigating the link between OSA and cognitive decline, there is still no consensus on whether OSA increases the risk of dementia or not. Part of the heterogeneity observed in previous studies might be related to some individual characteristics that modulate the association between OSA and cognitive decline. In this narrative review, we present these individual characteristics, namely, age, sex, menopause, obesity, diabetes mellitus, hypertension, cardiovascular diseases, smoking, excessive alcohol consumption, depression, air pollution, Apolipoprotein E ε4 allele, physical activity, and cognitive reserve. To date, large cohort studies of OSA and cognitive decline tended to statistically control for the effects of these variables, but whether they interact with OSA to predict cognitive decline remains to be elucidated. Being able to better predict who is at risk of cognitive decline when they have OSA would improve clinical management and treatment decisions, particularly when patients present relatively mild OSA.

Impact of sleep-disordered breathing on glucose metabolism among individuals with a family history of diabetes: the Nagahama study

STUDY OBJECTIVES

It is well known that a family history of diabetes (FHD) is a definitive risk factor for type 2 diabetes. It has not been known whether sleep-disordered breathing (SDB) increases the prevalence of diabetes in those with an FHD.

METHODS

We assessed SDB severity in 7,477 study participants by oximetry corrected by objective sleep duration determined by wrist actigraphy. Glycated hemoglobin ≥6.5% and/or current medication for diabetes indicated the presence of diabetes. In addition to the overall prevalence, the prevalence of recent-onset diabetes during the nearly 5 years before the SDB measurements were made was investigated.

RESULTS

Of the 7,477 participants (mean age: 57.9; range: 34.2-80.7; SD: 12.1 years; 67.7% females), 1,569 had an FHD. The prevalence of diabetes in FHD participants with moderate-to-severe SDB (MS-SDB) was higher than in those without SDB (MS-SDB vs without SDB: all, 29.3% vs 3.3% [P < .001]; females, 32.6% vs 1.9% [P < .001]; males, 26.2% vs 11.7% [P = .037]). However, multivariate analysis showed that MS-SDB was significantly associated with a higher prevalence of diabetes only in FHD-positive females (odds ratio [95% confidence interval]: females, 7.43 [3.16-17.45]; males, 0.92 [0.37-2.31]). Among the FHD-positive participants, the prevalence of recent-onset diabetes was higher in those with MS-SDB than those without SDB, but only in females (MS-SDB vs without SDB: 21.4% vs 1.1%; P < 0.001).

CONCLUSIONS

MS-SDB was associated with diabetes risk in females with an FHD, and future studies are needed on whether treatment of SDB in females with an FHD would prevent the onset of diabetes.

Night-time frequency of urination as a manifestation of sleep-disordered breathing: the Nagahama study

AIMS

Sleep-disordered breathing (SDB) is a well-known risk factor for cardiovascular outcomes. Studies of patients with SDB have identified frequent night-time urination as a manifestation related to SDB. We aimed to clarify whether night-time frequency of urination is independently associated with SDB in a general population. We also investigated whether night-time frequency of urination can help presumptive diagnose SDB.

METHODS

Study participants consisted of 7151 community residents. Oxygen saturation during sleep was measured for four nights using a pulse oximeter. SDB was defined as ≥15 events per hour in which oxygen desaturation exceeded or equal to 3% during an actigraphy-determined sleep period. Night-time frequency of urination was recorded for one week using a sleep diary.

RESULTS

Significant positive correlations were evident between night-time frequency of urination and SDB (none, 5.8%; once/night, 14.1%; twice/night, 20.1%; thrice/night, 28.7%; >thrice/night, 44.1%, P < 0.001). This association was independent of possible covariates, including sleep duration (adjusted odds ratio: once/night = 1.50, twice/night = 2.15, thrice/night = 3.07, >thrice/night = 3.73, P < 0.001). Other factors significantly associated with SDB were age, sex, obesity, observation of sleep apnea, and short sleep duration. The area under the curve of the risk score for SDB consisting of these conventional six items (0.834) significantly improved (0.842, P = 0.001) when night-time frequency of urination was considered as a risk score item.

CONCLUSION

Night-time frequency of urination was associated with SDB. Our findings suggest that the urination frequency should be considered a manifestation of SDB even in a general population.

Validation of Oximetry for Diagnosing Obstructive Sleep Apnea in a Clinical Setting

A large epidemiological study using oximetry to analyze obstructive sleep apnea (OSA) and metabolic comorbidities was performed in Japan; however, reliability and validity of oximetry in the Japanese population remains poorly understood. In this study, oximetry data from the epidemiological study were compared with data from clinically performed polysomnography (PSG) and out-of-center sleep testing (OCST) in epidemiological study participants who later attended our outpatient units. The oxygen desaturation index (ODI) from oximetry showed a moderate positive relationship (correlation coefficient r = 0.561, p < 0.001) with apnea/hypopnea data from PSG/OCST. The area under the receiver operating characteristic curve showed moderate accuracy of this method in the detection of moderate-to-severe or severe OSA. However, the optimal ODI thresholds to detect moderate-to-severe OSA and severe OSA were the same (ODI > 20.1). Oximetry may be a useful tool for screening moderate-to-severe or severe sleep apnea. However, it may be difficult to set an appropriate threshold to distinguish between moderate and severe sleep apnea by oximetry alone.