Kazuo Chin

• MD, PhD
• Head of Department at Kyoto University

Radar-based respiratory measurement is a promising tool for the noncontact detection of sleep apnea. Our team has reported that apnea events can be accurately detected using the statistical characteristics of the amplitude of respiratory displacement. However, apnea and hypopnea events are often followed by irregular breathing, reducing the detecti...

Study objectives: While nocturnal hypoxia caused by sleep-disordered breathing (SDB) can result in polycythemia, the association between erythrocyte values and SDB may vary by sex and menopausal status. This study aimed to evaluate the correlation of erythrocyte variables with SDB in a large cohort categorized by sex and menopausal status from the...

Background Diaphragm thickness is a potential marker of sarcopenia in addition to muscle mass and strength at extremities. We aimed to clarify the descriptive epidemiology and prognostic significance of diaphragm thickness in the general population. Methods The study participants were 3324 community residents (mean age: 61.4 ± 12.8 years) who part...

Nocturnal urination frequency is associated with sleep blood pressure (BP). However, it was uncertain to what extent the sleep BP increases within individuals with each increase in the number of nocturnal urination. We calculated intraindividual differences in sleep BP between nights with different urination frequencies to clarify their relationshi...

Background: Sleep apnea (SA), subjective sleep duration (SSD), and objective sleep duration (OSD) were reported as risk factors for atrial fibrillation (AF). However, the association between AF and the combination of SA and OSD has not been clarified. Nor has a mismatch between SSD and OSD been investigated. Methods and Results: We assessed SA with...

Sleep apnea syndrome requires early diagnosis because this syndrome can lead to a variety of health problems. If sleep apnea events can be detected in a noncontact manner using radar, we can then avoid the discomfort caused by the contact-type sensors that are used in conventional polysomnography. This study proposes a novel radar-based method for...

Background: The respiratory rate (RR) is a critical vital sign controlled by not only metabolic factors but behavior while awake. The prevalence of obstructive sleep apnea (OSA) is remarkably high. Therefore, a non-constraining and non-contact respiratory monitor to measure the RR both while awake and asleep is preferable. Methods: A millimeter wav...

Background Nocturnal blood pressure (BP) is associated with cardiovascular disease independently of awake BP. However, nocturnal BP measured using an ambulatory monitoring device has limited reproducibility because it is a single-day measurement. We investigated the association between sleep BP measured on multiple days using a timer-equipped home...

Objective Nocturnal blood pressure (BP) was reported to be associated with cardiovascular diseases. However, nocturnal BP measured using ambulatory monitoring device usually includes BP without sleep. We investigated an association between sleep BP measured using a timer-equipped home BP monitor and cardiovascular diseases in a general population....

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 inv...

Sleep apnea syndrome requires early diagnosis because this syndrome can lead to a variety of health problems. If sleep apnea events can be detected in a noncontact manner using radar, we can then avoid the discomfort caused by the contact-type sensors that are used in conventional polysomnography. This study proposes a novel radar-based method for...

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...

Little is known about the association of prolonged cough, a common and troublesome symptom, with metabolic pathways. We aimed to clarify this association using data from the Nagahama cohort, a prospective study of participants from the general population. Self-report questionnaires on prolonged cough were collected at baseline and 5-year follow-up...

Rationale Subjects with preserved ratio impaired spirometry (PRISm) experience increased respiratory symptoms, although they present heterogeneous characteristics. However, the longitudinal changes in these symptoms and respiratory function are not well known. Objective To investigate PRISm from the viewpoint of respiratory symptoms in a longitudin...

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 spectr...

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 s...

Background: Obesity and increased body mass index (BMI) are the known risk factors for adult-onset asthma. Serum free fatty acid (FFA) and other blood lipid levels are generally elevated in patients with obesity and may be involved in the onset of asthma. However, it remains largely unknown. This study aimed to elucidate the relationship between p...

A 54-year-old man whose awake percutaneous arterial oxygen saturation (SpO2) was 94% was diagnosed with obstructive sleep apnea by polysomnography (PSG). His apnea-hypopnea index (AHI) was 138.8 (AI: 4.7 and HI: 134.1), so he was treated with continuous positive airway pressure (CPAP), and his condition was considered well-controlled by the CPAP tr...

A 73-year-old man with putaminal hemorrhage was diagnosed with obstructive sleep apnea syndrome two yearsafter he suffered putaminal hemorrhage, which was well treated by continuous positive airway pressure (CPAP).Although his apnea hypopnea index (AHI), indicating the number of apnea or hypopnea episodes divided by thenumber of hours of sleep, had...

A woman in her late 20s who had received an implantable cardioverter defibrillator in childhood for ventricular arrhythmia was diagnosed with severe obstructive sleep apnoea (apnoea–hypopnoea index, 77.1/h), and she began continuous positive airway pressure treatment. Before initiating this treatment, she had moderate hypoxaemia of unknown cause. S...

Background Tocilizumab is considered a critical treatment for severe COVID-19. Thus far, there are no established means of predicting outcomes of administering tocilizumab. Our goal was to determine the factors that predict the prognosis of patients with COVID-19 receiving tocilizumab. Methods All patients admitted to our hospital from March 2020...

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...

Subjects with subclinical respiratory dysfunction who do not meet the chronic obstructive pulmonary disease (COPD) criteria have attracted attention with regard to early COPD intervention. Our aim was to longitudinally investigate the risks for the development of airflow limitation (AFL) and dyspnoea, the main characteristics of COPD, in a large-sc...

A woman in her 50s with Kleine–Levin syndrome (KLS) was referred to our sleep clinic for recurrent episodes of sleep hypersomnia lasting for two to three days, despite attempts to remain awake. These episodes were unaccompanied by anxiety or depression, increased appetite, increased sex drive, irritability, or hallucinations, and had first appeared...

To improve patients’ adherence to continuous positive airway pressure (CPAP) therapy, this study aimed to clarify whether machine learning-based data analysis can identify the factors related to poor CPAP adherence (i.e., CPAP usage that does not reach four hours per day for five days a week). We developed a CPAP adherence prediction model using lo...

Background Telemonitoring the usage of continuous positive airway pressure (CPAP) devices and remote feedback on device data effectively optimizes CPAP adherence in patients with obstructive sleep apnea (OSA). Research Questions Can expanding the scope of telemonitoring and remote feedback to body weight (BW), blood pressure (BP), and physical act...

This study investigated the performance of radar-based detection methods for sleep apnea, by comparing a machine learning approach and a non-machine learning approach. We applied a 79-GHz millimeter-wave multiple-input and multiple-output array radar with 12 virtual array elements and performed radar and polysomnography measurements simultaneously...

The Japanese government’s latest manual on COVID-19 management mentions non-invasive ventilation (NIV). Before this version, we experienced three cases in which COVID-19 was a concern. Each case had one of the following conditions: obesity hypoventilation syndrome, amyotrophic lateral sclerosis, acute heart failure with acute kidney injury with hyp...

Background: Home monitoring devices have been developed to measure adherence to home oxygen therapy. In this study, we evaluated the performance of TeleOx®, a commercially available remote monitoring device, in comparison with polysomnography (PSG) in patients with interstitial lung disease (ILD) and chronic obstructive pulmonary disease (COPD) an...

Cover image: The cover image is based on the Original Article Clinical, radiological and pathological features of idiopathic and secondary interstitial pneumonia with pleuroparenchymal fibroelastosis in patients undergoing lung transplantation by Naoya Ikegami et al., https://doi.org/10.1111/his.14595.

Sudden deterioration of condition in patients with various diseases, such as cardiopulmonary arrest, may result in poor outcome even after resuscitation. Early detection of deterioration is important in medical and long-term care settings, regardless of the acute or chronic phase of disease. Early detection and appropriate interventions are essenti...

The prevalence of sleep-disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern count...

The prevalence of sleep disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern count...

Purpose of Review Recently, the prevalence of obstructive sleep apnea (OSA) and diabetes has increased, and it is important to examine the association between OSA and diabetes and diabetic complications. We present a comprehensive review of classical studies and specifically describe the recent and longitudinal studies. Recent Findings OSA is a si...

Aims Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a rare type of idiopathic interstitial pneumonia, and pathological PPFE is also observed in secondary interstitial pneumonia. This study aimed to evaluate the pathological findings associated with radiological PPFE-like lesions and the clinical and morphological features of patients with pa...

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...

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. Method...

Blood eosinophil count is a useful measure in asthma or COPD management. Recent epidemiological studies revealed that body mass index (BMI) is positively associated with eosinophil counts. However, few studies focused on the role of adiposity and fatty acid-related metabolites on eosinophil counts, including the effect of genetic polymorphism. In t...

Study objectives: Whether the association between sleep-disordered breathing (SDB) and cardiovascular disease is independent of comorbid risk factors for cardiovascular disease is controversial. The objective of this study was to elucidate whether the association between SDB severity and the surrogate markers of cardiovascular disease events diffe...

Background Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic lung disease that leads to respiratory failure and death. Although there is a greater understanding of the etiology of this disease, accurately predicting the disease course in individual patients is still not possible. This study aimed to evaluate serum cytokines/che...

PurposeOur previous cross-sectional study showed that periodic limb movements during sleep (PLMS) were frequently found in patients with obstructive sleep apnea (OSA) and that both OSA and PLMS were associated with higher plasma fibrinogen levels. We explored the longitudinal relationships among these factors.Methods Plasma fibrinogen levels were m...

An online questionnaire survey was used to assess the application of noninvasive strategies in the management of COVID-19 patients. We found a marked increase in the proportion of facilities using high flow nasal cannula (HFNC) oxygen therapy successfully in the 3rd epidemic wave as compared to the 1st wave (49% vs. 12%) and rare reports of associa...

Background Waitlist mortality due to donor shortage for lung transplantation is a serious problem worldwide. Currently, the selection of recipients in Japan is mainly based on the registration order. Hence, scientific evidence for risk stratification regarding waitlist mortality is urgently needed. We hypothesized that patient-reported dyspnea and...

PurposePoor quality of sleep is a common feature in patients with various lung diseases and affects their health-related quality of life (HRQL). We evaluated sleep quality and HRQL in patients on the waitlist for lung transplantation in Japan.Methods In this prospective study, patient-reported and physiological data were collected from patients new...

Background Waitlist mortality due to donor shortage for lung transplantation is a serious problem worldwide. Currently, the selection of recipients is mainly based on registration order in Japan. However, scientific evidence for risk stratification for waitlist mortality is needed in future. We hypothesized that patient-reported dyspnea and health...

Background Chronic sputum production in the general population is historically associated with clinical indices including male sex and smoking history. However, its relationship with gastroesophageal reflux disease (GERD), which may prove an underlying factor in sputum production, is unclear. We aimed to clarify factors associated with sputum produ...

There is ambiguity in the interpretation of peripheral blood total eosinophil count, and several proposed cut-off values or thresholds of 300 cells per μL have been used to identify the patients who are most likely to benefit from inhaled corticosteroids. https://bit.ly/3ktCxof

Background:Sleep disordered breathing (SDB) is prevalent and associated with increased mortality in patients both with and without cardiovascular disease (CVD). Many portable monitoring devices, including peripheral arterial tonometry (PAT)-based devices, have been developed. Although previous studies have demonstrated that the apnea-hypopnea index...

Severe post-transplant hypoxemia, which is defined as <50 mm Hg of the partial pressure of oxygen in arterial blood/fraction of inspired oxygen (P/F) ratio, is a major post-operative complication with high mortality rates in patients with hepatopulmonary syndrome (HPS). Non-invasive positive pressure ventilation therapy and mechanical ventilation a...

Regnase-1 is an RNase critical for posttranscriptional control of pulmonary immune homeostasis in mice by degrading immune-related mRNAs. However, little is known about the cell types Regnase-1 controls in the lung, and its relevance to human pulmonary diseases. Regnase-1-dependent changes in lung immune cell types were examined by a competitive bo...

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 FHD. Methods: We assessed SDB severity in 7,477 study participants by oximetry corrected by objective sleep d...

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 investigate...

Background Therapy options for obstructive (OSA) and central (CSA) sleep apnea are limited, thus many patients remain untreated. Clinically acetazolamide is sometimes used for central sleep apnea (CSA), but given overlapping pathophysiology of OSA and CSA, we hypothesized that acetazolamide is equally effective for both types. Prior reviews focused...

Background: High sleep blood pressure (BP) has been suggested to be an independent risk factor for cardiovascular outcomes. To assess the applicability of sleep BP measured using a timer-equipped home device, we investigated the association between home device-measured sleep BP and large artery stiffness. Methods: We performed a cross-sectional...

Background: Periostin is a matricellular protein and is a useful marker in respiratory diseases. However, the roles of periostin in patients with obstructive sleep apnea (OSA) remain unclear. Several in vitro studies have suggested that mechanical stress, hypoxia, impaired metabolism, and kidney injury, which often accompany OSA, may upregulate th...

It is well known that the prevalence of sleep disordered breathing (SDB) is increased in patients with obesity or metabolic comorbidities. However, the way in which the prevalence of SDB increases in relation to comorbidities according to the severity of obesity remains unclear. This cross-sectional study evaluated 7713 community participants with...

Background Pulmonary arterial hypertension (PAH) is frequently complicated by sleep disordered breathing (SDB), and previous studies have largely focused on hypoxemic SDB. Even though nocturnal hypercapnia was shown to exacerbate pulmonary hypertension, the clinical significance of nocturnal hypercapnia among PAH patients has been scarcely investig...

Purpose We previously reported that sleep quality is impaired in waitlisted patients for lung transplantation in Japan, and that respiratory symptoms and psychological status were main contributive factors to sleep quality. However, it is unknown whether sleep quality would improve after lung transplantation or not. Then we aim to assess changes in...

Background: Improving health-related quality of life (HRQL) is an important goal of lung transplantation, and St. George's Respiratory Questionnaire (SGRQ) is frequently used for assessing HRQL in patients waitlisted for lung transplantation. We hypothesized that chronic respiratory failure (CRF)-specific HRQL measures would be more suitable than...

Aims As the glucose tolerance of patients with diabetes worsens, autonomic nervous system (ANS) function decreases. Only a few studies, using plasma glucose, have reported on this relationship in large general populations that include people with wide range of glycemia. This study aimed to examine correlates of ANS function with special reference t...

Rationale: The effects of telemedicine on adherence in obstructive sleep apnea patients with long-term continuous positive airway pressure (CPAP) use have never been investigated. Objectives: To examine effects of a telemedicine intervention on adherence in long-term CPAP users. Methods: In a prospective, randomized, multicenter non-inferiorit...

Objectives The association of obstructive sleep apnea (OSA) with hypothalamic pituitary adrenal (HPA) axis activation has not been fully understood from results of previous studies using hormonal assessments. We aimed to investigate the relationship between adrenal size, a potential marker reflecting HPA axis activity, and sleep parameters related...

Aim: Nocturia is a common phenomenon in older individuals, and is associated with poor quality of life. Nocturia is a multifactorial disorder, wherein the frailty of skeletal muscles, particularly muscle weakness in the lower trunk and hip regions, might be a risk factor in women. We analyzed a dataset of the general Japanese population to clarify...

Background: Nocturia is a risk factor for poor quality of life and increased mortality. This study was aimed to clarifying dietary habits, eating behaviors, and sleep characteristics associated with nocturia to identify modifiable lifestyle factors for nocturia. Methods: This cross-sectional study included 5683 community residents (64.5 ± 7.7 ye...

Nocturia in older adults has been reported to be a risk factor for cardiovascular outcomes, and the stiffening of large arteries might be an underlying mechanism. To clarify the possible association between nocturia and arterial stiffness, we analyzed a dataset from the Japanese general population. Study participants consisted of 5928 community res...

Background: Obesity affects the pathogenesis of various chronic diseases, including asthma. Research on correlations between obesity/BMI and eosinophilic inflammation in asthma has yielded contradictory results, which could be partly ascribed to the absence of epidemiological data on the correlations. We aimed to elucidate the correlations between...

Objective: We aimed to clarify the clinical significance of serum levels of MMPs in interstitial lung disease (ILD) complicated with PM/DM (PM/DM-ILD). Methods: We retrospectively analysed serum levels of seven subsets of MMPs in 52 PM/DM-ILD patients diagnosed at Kyoto University Hospital or Tenri Hospital from January 2005 to December 2014. Th...

Rationale: The Sarcoidosis Health Questionnaire (SHQ) is the first sarcoidosis-specific health status questionnaire ever developed. Worse health status, as evaluated by the SHQ, may indicate higher risk for deterioration in the following 5 years. Objectives: To evaluate the association between SHQ scores and deterioration defined clinically at 5...

Recently, interest in sleep disturbances, such as sleep disordered breathing (SDB), short sleep duration, and non-restorative sleep (NRS), has been increasing. The potentially large public health implications of sleep disturbances indicate a need to determine their prevalence in a general population. This review describes the characteristics of pop...

Objectives: We aimed to analyze associations of sleep disturbance, including sleep disordered breathing, sleep fragmentation, and sleep efficiency, with abnormal nocturnal blood pressure (BP) profiles that may be risk factors for adverse cardiovascular outcomes. Methods: The study included 5854 community residents with 20,725 multi-day measureme...

Objective The effects of partial pressure of arterial oxygen (PaO2) after introducing long-term noninvasive ventilation (NIV) on the prognosis of patients with restrictive thoracic disease and chronic respiratory failure are not exactly known. Methods Data from 141 patients with restrictive thoracic disease under long-term nocturnal NIV were retros...