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Objectives: Pain neuroscience education (PNE) has been shown to be effective in reducing pain in people with chronic musculoskeletal pain. Knowledge of pain physiology is necessary to undertake PNE, and a measure for such knowledge is necessary. The Knowledge and Attitudes of Pain (KNAP), a comprehensive assessment of knowledge, attitudes, and beliefs regarding pain for healthcare practitioners, was developed in 2020 through the assessment of construct validity, reliability, and responsiveness in Dutch and English. This study aimed to conduct cross-cultural adaptation of the KNAP into Japanese and to verify test-retest reliability among Japanese undergraduate physical therapy and occupational therapy students., Methods: Cross-cultural adaptation was performed using Beaton's five-step process. Subsequently, the KNAP was completed by participants with a 2-week interval. The study included second-, third-, and fourth-year undergraduate physical therapy and occupational therapy students., Results: A total of 50 students participated in the pilot test and a Japanese version of KNAP was created. Thirty-nine students completed the Japanese version of KNAP twice. Of the 30 items on the KNAP, the quadratic weighted kappa value was less than 0.4 for only one item (item 15), but reliability was interpreted as sufficient for the overall score, with an intraclass correlation coefficient (95% confidence interval) for the total score of 0.89 (0.80-0.94)., Conclusions: This study has developed the Japanese KNAP, which has shown preliminary evidence of adequate test-retest reliability in Japanese undergraduate physical therapy and occupational therapy students., Competing Interests: CONFLICTS OF INTEREST: The authors report no conflicts of interest., (2022 The Japanese Association of Rehabilitation Medicine.)

Objectives: For the technical management of tracheal anastomosis, developing new and simple methods is required to relieve anastomotic tension. This study aimed to investigate whether basic fibroblast growth factor (bFGF) only once injected immediately before anastomosis promotes cartilage regeneration at the tracheal anastomosis and whether the regenerated cartilage has the effect of reinforcing the anastomosis in a rabbit model., Methods: New Zealand white rabbits were anaesthetized, and the cervical trachea was exposed through a cervical midline incision, followed by resection of the 10th tracheal cartilage. The rabbits were categorized into 2 groups: the bFGF group (n = 6) and the control group (n = 6). In the former group, bFGF (25 μg) was administered into the submucosal layer of the cartilage using a 27-G needle immediately before tracheal anastomosis. The animals were sacrificed 4 weeks later. Histological, mechanical and biochemical evaluations were performed on this anastomosed trachea., Results: At 4 weeks of age, the anastomoses were spindle-shaped and displayed maximum diameter at the injection site compared with those in the control group. Histological evaluation showed that cartilage tissue had regenerated between the 9th and 11th tracheal cartilage rings. Tensile test showed that the anastomoses displayed a significantly high strain/stress ratio (P = 0.035). The collagen type II and glycosaminoglycan levels were significantly increased, and the collagen type I level was significantly decreased (P = 0.019, P = 0.013 and P = 0.045, respectively)., Conclusions: A new wound-healing concept of airway anastomosis could be provided by the results that single injection of bFGF regenerated tracheal cartilage in rabbits and strengthened the anastomosis by bridging the regenerated and well-matured cartilage. Further investigation of this method will lead to potential clinical applications for reinforcement of tracheal anastomoses., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

The purpose of this study was to develop a simulation approach for predicting maxillomandibular advancement-induced airway changes using computational fluid dynamics. Eight patients with jaw deformities who underwent maxillomandibular advancement and genioglossus advancement surgery were included in this study. Computed tomography scans and rhinomanometric readings were performed both preoperatively and postoperatively. Computational fluid dynamics models were created, and airflow simulations were performed using computational fluid dynamics software; the preferable number of computational mesh points was at least 10 million cells. The results for the right and left nares, including simulation and postoperative measurements, were qualitatively consistent, and surgery reduced airflow pressure loss. Geometry prediction simulation results were qualitatively consistent with the postoperative stereolithography data and postoperative simulation results. Simulations were performed with either the right or left naris blocked, and the predicted values were similar to those found clinically. In addition, geometry prediction simulation results were qualitatively consistent with the postoperative stereolithography data and postoperative simulation results. These findings suggest that geometry prediction simulation facilitates the preoperative prediction of the postoperative structural outcome., Competing Interests: The authors have declared that no competing interests exist.

Video 1Traction-assisted colorectal endoscopic submucosal dissection using the multiloop method for a previously tattooed laterally spreading tumor in the sigmoid colon., (© 2021 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc.)

This study aimed to investigate the short-term effectiveness of adalimumab therapy in patients with ulcerative colitis (UC), especially its rapid response.This retrospective, multicenter, cohort study involved 7 institutes in Japan, compiling data from patients with UC who had received at least 1 induction dose of 160 mg of adalimumab between June 2013 and May 2017. Patients should have a Lichtiger clinical activity index score of ≥5 at the initial adalimumab administration. Remission was defined as clinical activity index score of ≤4, whereas response was defined as a reduction of ≥50% from the baseline value. Rapid responders are defined as patients who achieved response at 2 weeks.A total of 91 patients were included in this study: 37.4% and 45.1% achieved clinical response at 2 and 8 weeks, respectively, whereas clinical remission rates 12 weeks were 45.1%. Among the rapid responders, 82.4% achieved clinical remission at 12 weeks. Multivariate logistic regression analysis identified a higher platelet count as an independent prognostic factor for a higher rate of rapid response. Receiver operating characteristic curve showed that a platelet counts cutoff value of ≥312 × 10/L was associated with a rapid response.Approximately 40% of patients with UC showed a rapid response to adalimumab therapy after 2 weeks. Up to 80% of the rapid responders also achieved remission at 12 weeks. A higher platelet count was identified as an independent prognostic factor for a higher rapid response rate.

Background and study aims  We previously reported on a novel traction method called Multiloop (M-loop) for faster colorectal endoscopic submucosal dissection (ESD). In this study, we retrospectively compared the difference in submucosal dissection time (SDT), and submucosal dissection speed (SDS) between groups of patients who were treated using traction with the M-loop method, and with non-traction methods of colorectal ESD. Patients and methods  We reviewed and timed duration of colorectal ESD by the non-traction method from videos recorded between June 2016 and December 2017. From January 2018 onward, we used the M-loop method during all colorectal ESDs and timed it until August 2018. Outcomes of colorectal ESD with the M-loop method and non-traction methods were compared. The study involved two experts and eight non-experts and was carried out at a tertiary endoscopic center in Japan. Results  The study included 50 patients who treated with the M-loop method and 115 patients treated with the non-traction method. Submucosal dissection time (SDT) was not significantly different (M-loop group, 42.1  ±  4.2 min, non-traction ESD group, 51.9 ± 3.3 min) ( P  = 0.098), but submucosal dissection speed (SDS) was significantly greater (M-loop group, 28.0 ± 2.9 mm 2  /min, non-traction ESD group, 19.9 ± 2.0 mm 2 /min) ( P  = 0.0014) in the M-loop method group. Multivariate analysis showed that the M-loop method increased SDS by odds ratio of 1.46 ( P  = 0.001) when compared to the non-traction ESD method. A significant difference was also observed for SDT and SDS when the two methods were compared after propensity score matching ( P  = 0.001). No differences in unfavorable outcomes were observed. Conclusions  The M-loop method improved SDS compared to non-traction methods of ESD. The method is an effective tool to assist colorectal ESD., Competing Interests: Competing interests The authors declare that they have no conflict of interest.

Objective: The purpose of this study was to investigate the effect of breathing route on the collapsibility of the pharyngeal airway in patients with obstructive sleep apnea by using computational fluid dynamics technology., Methods: This study examined Japanese men with obstructive sleep apnea. Computed tomography scans of the nose and pharynx were taken during nasal breathing with closed mouth, nasal breathing with open mouth, and oral breathing while they were awake. Three-dimensional reconstructed stereolithography models and digital unstructured grid models were created and airflow simulations were performed using computational fluid dynamics software., Results: Airflow velocity was significantly higher during oral breathing than during nasal breathing with open or closed mouth. No significant difference in maximum velocity was noted between nasal breathing with closed and open mouth. However, airflow during nasal breathing with open mouth was slow but rapidly sped up at the lower level of the velopharynx, and then spread and became a disturbed, unsteady stream. In contrast, airflow during nasal breathing with closed mouth gradually sped up at the oropharyngeal level without spreading or disturbance. Negative static pressure during oral breathing was significantly decreased; however, there were no significant differences between nasal breathing with closed or open mouth., Conclusions: Computational fluid dynamics results during nasal and oral breathing revealed that oral breathing is the primary condition leading to pharyngeal airway collapse based on the concept of the Starling Resistor model. Airflow throughout the entirety of the breathing route was smoother during nasal breathing with closed mouth than that with open mouth., Competing Interests: The authors have declared that no competing interests exist.

Maxillomandibular advancement surgery is useful for treatment of sleep apnea. However, preoperative analysis and evaluation to facilitate decision-making regarding the direction and distance of maxillomandibular movement has primarily consisted of morphological analysis; physiological function is not evaluated. To improve preoperative prediction, this study used fluid simulation to investigate the characteristics and effects of airway changes associated with maxillomandibular movement. A one-dimensional model with general applicability was thus developed. Actual measurements of flow in patients were used in this fluid simulation, thus achieving an analysis closer to clinical conditions. The simulation results were qualitatively consistent with the actual measurements, which confirmed the usefulness of the simulation. In addition, the results of the one-dimensional model were within the error ranges of the actual measurements. The present results establish a foundation for using accumulating preoperative measurement data for more-precise prediction of postoperative outcomes.

Background and study aims  We developed an e-learning program for endoscopic diagnosis of invasion depth of early gastric cancer (EGC) using a simple diagnostic criterion called non-extension sign, and the contribution of self-study quizzes to improvement of diagnostic accuracy was evaluated. Methods  We conducted a prospective randomized controlled study that recruited endoscopists throughout Japan. After completing a pretest, the participants watched video lectures and undertook post-test 1. The participants were then randomly allocated to either the self-study or non-self-study group, and participants in the first group completed the self-study program that comprised 100-case quizzes. Finally, participants in both groups undertook post-test 2. The primary endpoint was the difference in post-test 2 scores between the groups. The perfect score for the tests was set as 100 points. Results  A total of 423 endoscopists completed the pretest and were enrolled. Post-test 1 was completed by 415 endoscopists and 208 were allocated to the self-study group and 207 to the non-self-study group. Two hundred and four in the self-study group and 205 in the non-self-study group were included in the analysis. Video lectures improved the mean score of post-test 1 from 72 to 77 points. Participants who completed the self-study quizzes showed significantly better post-test 2 scores compared with the non-self-study group (80 vs. 76 points, respectively, P  < 0.0001). Conclusions  Our e-learning program showed that self-study quizzes consolidated knowledge of the non-extension sign and improved diagnostic ability of endoscopists for invasion depth of EGC.

Background and study aims  The usefulness of endoscopy for diagnosing histological type remains unclear. This study aimed to examine the diagnostic accuracy of white light endoscopy (WLE), magnified endoscopy with narrow band imaging (NBI-ME), and NBI-ME with acetic acid enhancement (NBI-AA) for histological type of gastric cancer. Patients and methods  Patients with depressed-type gastric cancers resected by endoscopic submucosal dissection were prospectively enrolled, and 221 cases were analyzed. Histological type was diagnosed by WLE, followed by NBI-ME and NBI-AA. Histological type was classified into differentiated adenocarcinoma and undifferentiated adenocarcinoma. Histological type was diagnosed based on lesion color in WLE, surface patterns (pit, villi, and unclear) and vascular irregularities in NBI-ME, and surface patterns in NBI-AA. Results  Histological types of target areas were differentiated adenocarcinoma and undifferentiated adenocarcinoma in 206 and 15 cases, respectively. Diagnostic accuracy of WLE, NBI-ME, and NBI-AA for the histological type was 96.4 % (213/221), 96.8 % (214/221), and 95.5 % (211/221), respectively. No significant differences were observed among modalities. Positive predictive value based on endoscopic findings in NBI-ME was 98.0 % (149/152) for the villi pattern, 100 % (19/19) for the irregular pit pattern, 100 % (9/9) for the unclear surface pattern with a vascular network, 90.3 % (28/31) for the unclear surface pattern with mild vascular irregularity, and 88.9 % (8/9) for the unclear surface pattern with severe vascular irregularity. Conclusions  NBI-ME and NBI-AA did not show any advantages over WLE for diagnostic accuracy. Villi pattern, irregular pit pattern, and vascular network may be useful for identifying differentiated adenocarcinoma.

Pancreatic cancer is a highly aggressive malignancy, with <50% patients surviving beyond 6 months after the diagnosis, and thus, there is an urgent need to explore new diagnostic and therapeutic approaches for this disease. Therefore, we conducted microRNA (miRNA) array analysis to detect miRNA molecules potentially associated with pancreatic cancer malignancy. To assess the identified miRNAs, we performed quantitative reverse transcription-PCR on 248 pancreatic ductal adenocarcinomas (UICC stage II). We also examined miRNA expression [microRNA-21 (miR-21) and microRNA-31 (miR-31)] and epigenetic alterations, including CpG island methylator phenotype (CIMP), potentially associated with the identified miRNAs. For functional analysis, we conducted proliferation and invasion assays using a pancreatic cancer cell line. miRNA array analysis revealed that microRNA-196b (miR-196b) was the most up-regulated miRNA in pancreatic cancer tissues compared with normal pancreatic duct cells. High miR-196b expression was associated with miR-21 (P = 0.0025) and miR-31 (P = 0.0001) expression. It was also related to poor prognosis in the multivariate analysis using overall survival (hazard ratio: 1.66; 95% confidence interval: 1.09-2.54; P = 0.019). Functional analysis demonstrated that miR-196b inhibitor decreased cell proliferation and that miR-196b mimic promoted cancer cell invasion. In conclusion, a significant association of high miR-196b expression with poor prognosis was observed in pancreatic cancer. Our data also revealed that miR-196b played an oncogenic role and that the transfection of the miR-196b inhibitor had an anti-tumour effect in the pancreatic cancer cell line. These results suggest that miR-196b is a promising diagnostic biomarker and therapeutic target in pancreatic cancer., (© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Polycomb group protein enhancer of zeste homolog 2 (EZH2) is a methyltransferase that correlates with the regulation of invasion and metastasis and is overexpressed in human cancers such as colorectal cancer. MicroRNA-31 (miR-31) plays an oncogenic role and is associated with BRAF mutation and poor prognosis in colorectal cancer. EZH2 is functionally considered to suppress miR-31 expression in human cancers; however, no study has reported its relationship with colon cancer. We therefore evaluated EZH2 expression using immunohistochemistry and assessed miR-31 and epigenetic alterations using 301 colorectal carcinomas and 207 premalignant lesions. Functional analysis was performed to identify the association between EZH2 and miR-31 using cancer cell lines. In the current study, negative, weak, moderate, and strong EZH2 expressions were observed in 15%, 19%, 25%, and 41% of colorectal cancers, respectively. EZH2 was inversely associated with miR-31 (P < 0.0001), independent of clinicopathological and molecular features. In a multivariate stage-stratified analysis, high EZH2 expression was related to favorable prognosis (P = 0.0022). Regarding premalignant lesions, negative EZH2 expression was frequently detected in sessile serrated adenomas/polyps (SSA/Ps) (76%; P < 0.0001) compared with hyperplastic polyps, traditional serrated adenomas, and non-serrated adenomas (25-36%). Functional analysis demonstrated that the knockdown of EZH2 increased miR-31 expression. In conclusion, an inverse association was identified between EZH2 and miR-31 in colorectal cancers. Our data also showed that upregulation of EZH2 expression may be rare in SSA/Ps. These results suggest that EZH2 suppresses miR-31 in colorectal cancer and may correlate with differentiation and evolution of serrated pathway.

Objective: Nasal obstruction is a common problem in continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea and limits treatment compliance. The purpose of this study is to model the effects of nasal obstruction on airflow parameters under CPAP using computational fluid dynamics (CFD), and to clarify quantitatively the relation between airflow velocity and pressure loss coefficient in subjects with and without nasal obstruction., Methods: We conducted an observational cross-sectional study of 16 Japanese adult subjects, of whom 9 had nasal obstruction and 7 did not (control group). Three-dimensional reconstructed models of the nasal cavity and nasopharynx with a CPAP mask fitted to the nostrils were created from each subject's CT scans. The digital models were meshed with tetrahedral cells and stereolithography formats were created. CPAP airflow simulations were conducted using CFD software. Airflow streamlines and velocity contours in the nasal cavities and nasopharynx were compared between groups. Simulation models were confirmed to agree with actual measurements of nasal flow rate and with pressure and flow rate in the CPAP machine., Results: Under 10 cmH2O CPAP, average maximum airflow velocity during inspiration was 17.6 ± 5.6 m/s in the nasal obstruction group but only 11.8 ± 1.4 m/s in the control group. The average pressure drop in the nasopharynx relative to inlet static pressure was 2.44 ± 1.41 cmH2O in the nasal obstruction group but only 1.17 ± 0.29 cmH2O in the control group. The nasal obstruction and control groups were clearly separated by a velocity threshold of 13.5 m/s, and pressure loss coefficient threshold of approximately 10.0. In contrast, there was no significant difference in expiratory pressure in the nasopharynx between the groups., Conclusion: This is the first CFD analysis of the effect of nasal obstruction on CPAP treatment. A strong correlation between the inspiratory pressure loss coefficient and maximum airflow velocity was found.

Recently, bacterial infection causing periodontal disease has attracted considerable attention as a risk factor for pancreatic cancer. Fusobacterium species is an oral bacterial group of the human microbiome. Some evidence suggests that Fusobacterium species promote colorectal cancer development; however, no previous studies have reported the association between Fusobacterium species and pancreatic cancer. Therefore, we examined whether Fusobacterium species exist in pancreatic cancer tissue. Using a database of 283 patients with pancreatic ductal adenocarcinoma (PDAC), we tested cancer tissue specimens for Fusobacterium species. We also tested the specimens for KRAS, NRAS, BRAF and PIK3CA mutations and measured microRNA-21 and microRNA-31. In addition, we assessed epigenetic alterations, including CpG island methylator phenotype (CIMP). Our data showed an 8.8% detection rate of Fusobacterium species in pancreatic cancers; however, tumor Fusobacterium status was not associated with any clinical and molecular features. In contrast, in multivariate Cox regression analysis, compared with the Fusobacterium species-negative group, we observed significantly higher cancer-specific mortality rates in the positive group (p = 0.023). In conclusion, Fusobacterium species were detected in pancreatic cancer tissue. Tumor Fusobacterium species status is independently associated with a worse prognosis of pancreatic cancer, suggesting that Fusobacterium species may be a prognostic biomarker of pancreatic cancer.

MicroRNAs have been increasingly recognized as useful biomarkers for colorectal cancers (CRC). We have recently observed that microRNA-31 (miR-31) expression is associated with BRAF mutation and prognosis in CRC. Moreover, high miR-31 expression is frequently detected in sessile serrated adenomas compared with hyperplastic polyps (HPs). These results suggest that miR-31 may contribute to the progression of serrated lesions. At a follow-up colonoscopy, we observed the case of a 75-year-old man with a 7-mm flat-elevated lesion in the cecum and diagnosed the lesion as an early invasive carcinoma with serrated features. Tissue specimens were obtained from the representative areas to compare the molecular alterations in the carcinoma component with those in the HP component. Higher miR-31 expression was observed in the carcinoma component (57-fold increase) and the HP component (8-fold increase) compared with the paired normal mucosa, suggesting that miR-31 may be one of the key molecules in serrated pathway progression.

Background: Magnifying endoscopy with narrow-band imaging (ME-NBI) and a simple and systematic classification system based on microvascular and microsurface patterns, the "VS" classification system (VSCS), have been shown to be useful for the diagnosis of early gastric cancer. The aim of this study was to clarify whether an educational lecture about the VSCS improves performance with ME-NBI., Methods: Sixty-four gastrointestinal endoscopists took the 1st exam before receiving the lecture about the VSCS, the 2nd exam immediately after the lecture, and the 3rd exam 2 months after the lecture. We compared the VSCS-based diagnostic accuracy among the participants before and after the lecture., Results: The proportion of correct diagnoses was significantly higher, at 70.8% in the 2nd exam than in the 1st exam, at 53.1% (P<0.001). The correct diagnosis rate in the 3rd exam was significantly lower than that in the 2nd exam (60.9% vs. 70.8%; P<0.001) but was still higher than that in the 1st exam (60.9% vs. 53.1%; P<0.001). The difference in proportion of correct diagnosis between the 2nd and the 3rd exams was smaller among routine ME-NBI practitioners (n=6; 79.2% and 76.1%, respectively), compared to that among non-routine practitioners (n=34; 71.6% and 59.8%, respectively) or non-practitioners (n=24; 67.5% and 58.8%, respectively)., Conclusion: This study revealed that an educational intervention increased correct diagnosis rate of small gastric lesions using the VSCS, diagnosis criteria based on ME-NBI and also showed that the routine use of the modality and the diagnosis criteria was necessary to maintain diagnostic skills.

Ca2+ is a chemopreventive agent for colon cancer. Ion transport systems are often altered in human cancer. The aim of this study was to clarify the alterations of calcium-sensing receptor (CASR), a member of the G protein-coupled receptor family, in colorectal carcinogenesis. We analyzed the expression of CASR in colorectal cancer cell lines and in cancer and adenoma tissues by RT-PCR and immunostaining. In addition, we analyzed methylation of the CASR promoter by using bisulfite sequence analysis and methylation-specific PCR. CASR mRNA and protein expression was significantly downregulated in most of the cancer cell lines. CpG islands were densely methylated in cancer cell lines with reduced CASR mRNA expression. Treatment with a demethylating agent, 5-aza-2'-deoxycytidine, and/or a histone deacetylase inhibitor, trichostatin A, restored CASR expression in the cancer cell lines. Disruption of CASR expression in CASR-unmethylated HCT-8 cells blocked the enhancing effect of Ca2+ on the cytotoxic response to 5-fluorouracil. CASR expression was observed in normal colonic epithelial cells and was retained in most adenoma tissues. CASR mRNA and protein expression was significantly downregulated in cancer tissues. There was an inverse relationship between CASR expression and degree of differentiation. Immunohistochemical CASR staining was reduced more predominantly in less-differentiated cancer tissues and/or in cancer cells at the invasive front, where nuclear/cytoplasmic β-catenin was often localized. CASR methylation was detected in 69% of colorectal cancer tissues and 90% of lymph node metastatic tissues and was significantly correlated with reduced CASR expression. CASR methylation was also detected in 32% of advanced adenoma tissues but was detected in only 9% of adenoma tissues and was not detected in hyperplastic polyp tissues. CASR methylation seems to occur at an early stage and progress in colorectal carcinogenesis. The results suggest that epigenetic inactivation of CASR has an important role in colorectal carcinogenesis.

Introduction: More effective regimens are urgently needed for squamous cell carcinoma of esophagus (SCCE), therefore, we conducted a phase I/II trial of a combination of docetaxel, platinum, and fluorouracil (TPF) for treating metastatic SCCE., Methods: This phase I/II trial (n = 12/39) was conducted in our institute from April 2005 to June 2008. Progression-free survival (PFS) and overall survival were analyzed by the Kaplan-Meier method., Results: The recommended dose of docetaxel was determined to be 50 mg/m in phase I. In phase II with a mean follow-up period of 13.3 months, the objective response rate was 66.6%, a median survival period of 13 months and PFS of 7 months was achieved, and the 1-year survival and PFS rates were 52.9% and 19.6%, respectively. Grade 3/4 toxicities of leukopenia, neutropenia, and anorexia were observed in 53.8%, 43.6%, and 25.6%, respectively., Conclusions: A TPF regimen against metastatic SCCE was well tolerated and achieved a favorable objective response rate and survival benefit compared with other recently reported regimens. Randomized phase III trials of the TPF regimen are warranted and urgently required.

Background: Keeping hamsters as pets has been increasing markedly. Clinical reports have suggested that hamster or other pet ownership is associated with respiratory symptoms. However, this association has not been fully investigated by population-based studies in Japan. The aim of the present study was to investigate the relationship between hamster ownership and respiratory symptoms by using a questionnaire., Methods: During the period of August 1 to 20, 2002, we conducted a cross-sectional survey in Saitama Prefecture, which has a total population of approximately 7 million. First, we selected, proportionally to the population size, 100 areas from 5 administration districts of Saitama Prefecture. From each area, 30 households were chosen: 15 living in detached houses and 15 living in other types of dwelling, such as apartment houses. In this way, 2 groups based on type of dwelling (detached house versus other types) could be studied. A lay away plan was carried out. For the survey, 2 questionnaires were developed. One was a questionnaire dealing with household conditions, including pet keeping. The other sought details regarding individual health and lifestyle conditions. The questionnaire dealing with respiratory symptoms asked "whether the respondents had experienced respiratory symptoms (wheezing and/or breathlessness and/or bad cough) in the last 12 months.", Results: The response rate was 78.9%. There were 7,395 respondents in 2,368 households. There was no association between either dog or cat ownership and respiratory symptoms. In contrast, hamsters kept in the home were positively associated with respiratory symptoms. In a multivariate logistic regression analysis, hamster ownership increased the odds ratio for respiratory symptoms (odds ratio: 1.57; 95% confidence interval: 1.18-2.10)., Conclusion: This large size population-survey indicated that hamster ownership is associated with respiratory symptoms.