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Strongyloidiasis, an intestinal parasitic infection caused by Strongyloides stercoralis, rarely occurs in Japan. When treated with immunosuppressive drugs, two potentially lethal conditions, hyperinfection and dissemination, may develop in asymptomatic carriers of this parasite. We report the development of strongyloidiasis during treatment of polymyositis with glucocorticoids plus rituximab (RTX). A 44-year-old woman had been diagnosed with anti-signal recognition particle antibody–positive polymyositis with interstitial pneumonia 6 years previously, for which she had recently been receiving prednisolone at 5 mg/day and RTX at 375 mg/m2 twice every 3 months. Her condition appeared to be well controlled. She was admitted to our hospital with a 1-month history of chronic diarrhoea and epigastric pain. Standard microscopic examination of a sample of faeces revealed the presence of S. stercoralis; however, serologic testing for parasites was negative. Treatment with ivermectin alleviated her inflammatory diarrhoea and eradicated the faecal parasites. We believe that our patient had an exacerbation of S. stercoralis infection (hyperinfection syndrome) that was exacerbated by low-dose glucocorticoids plus RTX. Strongyloidiasis should be considered in immunocompromised individuals with unexplained diarrhoea, even in non-endemic areas.

Background Weight-loss approaches involving mindfulness have been reported to reduce overeating behavior. We conducted a preliminary evaluation of the feasibility and effectiveness of a mindfulness mobile application (MMA) combined with a comprehensive lifestyle intervention (CLI) focused on weight loss and eating behaviors for people with metabolic syndrome based on post-intervention follow-up data. Method Participants were randomly assigned (1:1) to a CLI group or a CLI + MMA group. Participants received weekly CLI for 13 weeks, followed by telephone counseling for 13 weeks. The CLI + MMA group also had access to the MMA. Feasibility was assessed by the number of people who refused to participate, rate of adherence to the MMA, follow-up rate, and participant satisfaction. The preliminary endpoint was weight change (at 26 weeks). Participants completed the Dutch Eating Behavior Questionnaire (DEBQ). A mixed linear model was used for efficacy analysis. Results Eight of the 40 participants declined to participate. The MMA was used 4.4 ± 1.7 days per week, but the rate of adherence declined over time. The follow-up rate was 100%, and there was no difference in participant satisfaction between the groups. There was no significant group-by-time interaction for weight loss (p = 0.924), but there was a significant interaction for the DEBQ restrained eating score (p = 0.033). Conclusions This study found that CLI plus MMA was highly feasible and moderately acceptable. There were no significant differences in weight loss between the groups, but the CLI + MMA group showed an increase in restrained eating. Further large-scale studies are needed. Trial Registration Japanese University Hospital Medical Information Network (UMIN-ICDR). Clinical Trial identifier number UMIN000042626.

Corynebacterium simulans was first reported in 2000. Although it is a member of the normal skin flora, some cases of C. simulans infection have been reported. Other Corynebacterium spp. rarely cause chronic pyogenic spondylitis, and pyogenic spondylitis caused by C. simulans has not been reported at all. Here we report a case of acute pyogenic spondylitis due to C. simulans. A 78-year-old man with diabetes mellitus visited our hospital with a 3-day history of lower back pain and fever. Blood culture revealed C. simulans and magnetic resonance images of lumbar vertebrae showed pyogenic spondylitis. He recovered after treatment by vancomycin for 9 weeks and was discharged home. No recurrence has been observed for half a year. This is likely the first reported case of pyogenic spondylitis by C. simulans. In general, Corynebacterium spp. cause chronic pyogenic spondylitis, but this case showed an acute course.

Supplemental material, sj-pdf-1-jtt-10.1177_1357633X211010981 for Impact of telephone support programme using telemonitoring on stage of change towards healthy eating and active exercise in people with prediabetes by Naoki Sakane, Yoshitake Oshima, Kazuhiko Kotani, Akiko Suganuma, Kaoru Takahashi, Juichi Sato, Sadao Suzuki, Kazuo Izumi, Masayuki Kato, Mitsuhiko Noda and Hideshi Kuzuya in Journal of Telemedicine and Telecare

Patient: Male, 84 Final Diagnosis: Intramural hematoma of esophagus Symptoms: Chest pain • hematemesis Medication: — Clinical Procedure: Esophagogastroduodenoscopy Specialty: Gastroenterology and Hepatology Objective: Diagnostic/therapeutic accidents Background: Intramural hematoma of the esophagus (IHE), a rare manifestation of acute mucosal injuries of the esophagus, can be caused by trauma such as endoscopic surgeries. Coagulation disorders increase the risk of IHE. The most common location of IHE is in the distal esophagus. The characteristic clinical triad of manifestations comprises acute retrosternal pain, odynophagia or dysphagia, and hematemesis. It is important to distinguish IHE from other acute conditions such as acute coronary syndrome, aortic dissection, and pulmonary embolism. Case Report: An 84-year-old male was scheduled for coil embolization for an endoleak after endovascular aneurysm repair. For this reason, he was taking aspirin and warfarin. A nasogastric tube had been inserted during surgery and subsequently removed without any problems reported. Postoperatively, he experienced chest pain and hematemesis of sudden onset. Urgent esophagogastroduodenoscopy demonstrated a large, dark red, non-pulsatile, submucosal, esophageal mass in the area of the mid-esophagus with a little oozing. He was diagnosed as having an IHE; other possible diagnoses were excluded by contrast-enhanced computed tomography and aortography. He was treated with fasting, a proton pump inhibitor, and cessation of anti-thrombotic drugs; he recovered completely. The bleeding spot in the esophagus was in the area of the mid-esophagus, which was around the second natural constriction site. It was possible that the nasogastric tube had contact with the esophageal wall at this second natural constriction, and caused intramural esophageal bleeding. Conclusions: Nasogastric tubes are not generally recognized as a cause of IHE. However, they can cause them, especially when a patient is taking anti-thrombotic drugs.

Introduction This study evaluated the impact of a telephone support programme with telemonitoring on changes in healthy eating and active exercise in adults with prediabetes using the stage of change framework. Methods We performed a post hoc analysis using data from the Japan Diabetes Outcome Trial-1. A total of 2607 participants aged 20–65 years with impaired fasting glucose were recruited from the workplace/community in Japan and randomized to a one year telephone support programme intervention arm ( n = 1240) or self-directed control arm ( n = 1367). Participants in both arms received monthly data feedback from a weight scale and pedometer. The main outcome measure was the stages of change toward healthy eating and active exercise. The secondary outcome was fasting plasma glucose (FPG). Results After the one year intervention, the adjusted odds ratio of progressing to the action/maintenance stage in the intervention vs. control arm for healthy eating was 1.31 (95% confidence interval (CI) 1.21–1.43; p Discussion These findings suggest that the telephone support programme by healthcare providers advanced the stage of changes toward healthy eating in people with prediabetes. In particular, it decreased FPG levels in the contemplation stage.

Background There is limited quantitative research on the effect of physician attire on patient–physician relationships. This study aimed to measure the influence of Japanese family physicians’ attire on the “human” aspects of medical care in terms of patient-perceived relational empathy. Methods This was a multicenter, prospective, controlled trial conducted in primary clinics in Japan. We explored the effects of family physician attire (white coat vs. casual attire) on patient-perceived empathy. Family physicians were allocated to alternate weeks of wearing a white coat or casual attire during consultations. Patients’ perceptions of physician empathy were evaluated using the self-rated Japanese Consultation and Relational Empathy (CARE) Measure. We used a linear mixed model to analyze the CARE Measure scores, adjusting for cluster effects of patients nested within doctor, age, and sex of patients, and doctors’ sex and years of clinical experience. We used the same method with Bonferroni adjustment to analyze patient sex differences in perceived empathy. Results A total of 632 patients of seven family physicians were allocated to white coat-wearing consultations (n = 328), and casual attire-wearing consultations (n = 304). There was no difference in CARE Measure scores between white coat and casual primary care consultations overall (p = 0.162). Subgroup analysis of patient sex showed that CARE Measure scores of male patients were significantly higher in the Casual group than in the White coat group (adjusted p-value = 0.044). There was no difference in female patient scores between White coat and Casual groups (adjusted p-value = 1.000). Conclusions This study demonstrated that physician attire (white coat or casual attire) in a primary care setting did not affect patient-perceived relational empathy overall. However, male patients of physicians wearing casual attire reported higher physician empathy. Although empathy cannot be reduced to simple variables such as attire, white coats may have a negative effect on patients, depending on the context. Family physicians should choose their attire carefully. Trial registration Japanese University Hospital Medical Information Network (UMIN-ICDR). Clinical Trial identifier number UMIN000037687 (Registered August 14, 2019, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000042749). The study was prospectively registered.

Objective We aimed to test our hypothesis that traditional Japanese (Kampo) medicine, hochuekkito (Hochu-ekki-to: HET) has a preventive effect for the symptoms on COVID-19. Trial design The study is designed as a multi-center, interventional, parallel-group, randomized (1:1 ratio), investigator sponsored, two-arm study. Participants Six thousand participants will be recruited from healthy hospital workers in 7 Japanese University Hospitals. Inclusion criteria: 1. Age from 20 to 75 years old at the time of registration 2. Asymptomatic and body temperature below 37°C at the time of registration 3. Capable of eating orally Exclusion criteria: 1. Previous upper respiratory inflammation due to viral infection (including suspected COVID-19) 2. Taking immunosuppressants 3. Allergic to the Kampo medicines used in this study 4. History of hypokalaemia, severe hypertension, severe liver dysfunction, and interstitial pneumonia 5. Regularly taking other Kampo medicines 6. Pregnant or possibly pregnant 7. Participating in other research 8. Judged to be unsuitable for this study by the doctor in charge Intervention and comparator Kampo group: participants receive HET in 9 tablets 2 times per day for 8 weeks. Control group: participants receive placebo in the same dosage as the Intervention group - 9 tablets 2 times per day for 8 weeks. Placebo tablets are identical in appearance and package to HET. Taste of placebo is different from that of HET. The Ohsugi Pharmaceutical Co. Ltd, Osaka, Japan manufactured the placebo and HET. Main outcomes Primary outcome: Number of patients with a SARS-CoV-2 RNA by ploymerase chain reaction (PCR) positive result with at least one symptom (fever, cough, sputum, malaise, shortness of breath) during the 12-week study period (including the 4-week observation period after oral administration). Secondary outcomes: 1. Period from infection to onset 2. Period from the appearance of symptoms to the disappearance of PCR positive 3. Number of days until the appearance or improvement of symptoms 4. Severe stage: presence of hospitalization 5. Shock stage: ICU management required for mechanical ventilation, shock vitals or failure of organ(s) other than lungs Safety endpoints include numbness in the hands and/or feet, edema, skin rash or other allergic symptoms, and gastric discomfort. Randomisation Patients are randomized (1:1 ratio) to each group using minimization implemented with the Electric data capture system (DATATRAK Enterprise Cloud), with balancing of the arms with age range (under 50 years of age or not) and having a history of risk factors for COVID-19 (cardiovascular disease, hypertension, diabetes, respiratory diseases). Blinding (masking) Only participants will be randomized. Numbers to be randomised (sample size) The main research hypothesis of this study is that Kampo medicines significantly prevent the onset of COVID-19. It is assumed that the infection rate before the administration of the drug under consideration will be 0% and that the incidence of COVID-19 thereafter will be 2- 3%, of which 70%-80% will show symptoms of COVID-19. Assuming that the pharmaceutical effect of the drug will be effective in 50% of patients and that the incidence rates in the placebo and drug groups will be 1.4%-2.4% and 0.7%-1.2%, respectively, the placebo is calculated at 2%, and the study drug at 1%. Since the frequency of verification is low and the number of cases will be large, we set a total of 10 analyses (9 interim analyses and a final analysis). Since the number of cases at the time of the final analysis will be 4,986 under the conditions of α = 0.05 and a power of 80% by the Peto method. We set at 600 cases in each interim analysis with an estimated dropout rate of 16.9%. Finally, the total number of cases is set to 6,000 with 3,000 in the placebo group and 3,000 in the HET group. Trial status Protocol version 1.3 of October 23rd , 2020. Recruitment start (expected): December 1st, 2020. Recruitment finish (expected): December 31st, 2022. Trial registration This trial is registered in the Japan Registry of Clinical Trials (jRCT) (jRCTs031200150) on 14 October 2020. Full protocol The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest of expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Many studies have examined the impression made on patients by physicians’ attire. Regardless of practice location, many patients express most confidence in physicians who wear white coats. The number of physicians in Japan who choose not to wear white coats in practice has been increasing, particularly in primary care settings. However, very few studies have examined physician preference for attire. To clarify Japanese general practitioners’ preference for attire by practice setting, we conducted a survey of physician preferences and reasons for attire selection. Subjects were 794 general practitioners certified by the Japan Primary Care Association and recruited from a mailing list. We conducted a web-based questionnaire survey. Physicians were asked to choose one of four different dress styles (semi-formal, white coat, scrubs, and casual) for different practice settings and state the reasons for selection. The response rate was 19.3% (n = 153; men 112). Most subjects chose white coats as usual attire for hospital practice (52%), mainly because of custom and professionalism. In contrast, most subjects chose non-white coats for clinics (59%) and home care (hospital-provided, 58%; clinic-provided, 71%). More subjects chose casual dress for clinic and home care practice, mainly to appear empathic. Most subjects chose white coats as the most appropriate hospital attire (54%), mainly because of patient perceptions of this attire being professional. Most subjects considered non-white coat attire more appropriate for clinic and home care practice. The findings indicate that general practitioners choose their clothes depending on practice location.

A 55-year-old Japanese man was diagnosed with VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome, which is a newly documented adult-onset autoinflammatory disease caused by somatic UBA1 mutations [1], after four years of symptoms. He had suffered from recurrent fever after the onset of systemic arthralgia, scleritis, periorbital/orbital inflammation, optic perineuritis (A, B, T1-weighted contrast-enhanced magnetic resonance imaging in C and D, arrow in D), and myelodysplastic syndrome.

Objectives Frequent self-weighing is associated with weight loss and maintenance, but the relationship between frequent self-weighing and the incidence of type 2 diabetes (T2D) remains unclear. The study aim was to examine the association between self-weighing frequency and the incidence of T2D in people with impaired fasting glucose (IFG). Results We tested the hypothesis that self-weighing frequency and the incidence of T2D are associated in 2607 people with IFG (1240 in the intervention arm; 1367 in the self-directed control arm). Both arms received a weighing scale with storage function. Healthcare providers offered a one-year goal-focused lifestyle intervention via phone. Participants were divided into 4 categories based on self-weighing frequency (No data sent [reference group], low: Trial registration This trial has been registered with the University Hospital Medical Information Network (UMIN000000662).

Objectives Using annual health check‐up data, the aim of this study was to identify target populations for lifestyle interventions to effectively prevent diabetes in a real‐world setting. Methods The Japan Diabetes Outcome Intervention Trial‐1, a prospective, cluster‐randomized controlled trial, was launched to test if year‐long telephone‐delivered lifestyle support by health professionals can prevent the development of type 2 diabetes (T2D) in people with impaired fasting glucose (IFG) identified at health check‐ups. A total of 2607 participants aged 20‐65 years with IFG were randomized to an intervention arm (n = 1240) or a control arm (n = 1367). We performed subgroup analysis to examine the effects of the intervention on the incidence of T2D in participants with body mass index (BMI) ≥25, metabolic syndrome (MetS), and non‐alcoholic or alcoholic elevated liver enzymes at the baseline. Cox regression analysis adjusted for sex was used to calculate the hazard ratios (HRs). Results In addition to IFG, the presence of BMI ≥25, MetS, and elevated liver enzymes increased the incidence of diabetes by two‐ or three‐fold. During a median follow‐up period of 4.9 years, only the non‐alcoholic elevated liver enzyme group showed a low incidence rate owing to lifestyle interventions (adjusted HR: 0.42, 95% confidence interval: 0.18‐0.98). Conclusion The results suggest that people who have IFG and non‐alcoholic elevated liver enzymes are a good target population for lifestyle interventions to effectively reduce the incidence of diabetes in a real‐world setting.

Additional file 1: Table S1. Baseline characteristics of the participants according to categories of self-weighing frequency.

Background: Limited evidence is available about the relationship of lifestyle factors with glycated hemoglobin (HbA1c) in subjects with impaired glucose tolerance. The aim of study was to identify such determinant factors of HbA1c in subjects with impaired glucose tolerance. Methods: This cross-sectional study included 121 men and 124 women with impaired glucose tolerance, who were diagnosed based on a 75-g oral glucose tolerance test. Demographic and biochemical parameters, including the body mass index (BMI), fasting plasma glucose (FPG), 2-h post-load glucose (2-h PG), and HbA1c, were measured. The pancreatic β-cell function and insulin resistance were assessed using homeostasis model assessment (HOMA-β). Dietary intake was assessed by a food frequency questionnaire. Results: The levels of FPG, 2-h PG, and carbohydrate intake were correlated with the HbA1c level in men, while the FPG and 2-h PG levels were correlated with the HbA1c level in women. In multiple regression analyses, BMI, FPG, 2-h PG, and white rice intake were associated with HbA1c levels in men, while BMI, FPG, HOMA-β, and bread intake were associated with HbA1c levels in women. Conclusions: The present findings suggest that a substantial portion of HbA1c may be composed of not only glycemic but also several lifestyle factors in men with impaired glucose tolerance. These factors can be taken into consideration as modifiable determinants in assessing the HbA1c level for the diagnosis and therapeutic monitoring of the disease course. J Clin Med Res. 2017;9(4):360-365 doi: https://doi.org/10.14740/jocmr2928w

Background: Evidence of the long-term benefits of telephone-delivered lifestyle interventions is limited. This study investigated the ability of telephone-delivered lifestyle intervention ...

Introduction Head hair is a symbol of vitality, and hair loss by alopecia areata (AA) presents a burden on patients. Although traditional Japanese Kampo medicine (JKM) formulas, acupuncture, and moxibustion have historically been used for treating AA, no studies have utilized a combination of these modalities. Patient concerns A 34-year-old male with a history of childhood asthma presented with a sudden hair loss at the top of his head without any preceding symptoms. Except for a hairless patch of 5 cm × 6 cm, his general appearance was otherwise good. The patient underwent topical immunotherapy on visiting a dermatologist. However, the patient noticed an exacerbation of his hairless lesion. Diagnosis The AA diagnosis was established based on clinical appearance and dermatological findings. The Severity of Alopecia Tool (SALT) score for alopecia was 19% at diagnosis. Interventions The patient received 2 JKM formulas (saikokaryukotsuboreito and shichimotsukokato) in combination with acupuncture. When relapse occurred, a novel self-administration of pine-needle acupuncture was initiated in combination with the JKM formulas. Outcomes A 50% recovery from the baseline SALT score was achieved using JKM formulas in combination with acupuncture for 4 months. The patient achieved complete remission for 5 months. However, another stressful event induced an AA relapse with multiple lesions harboring a SALT score of 13%. Pine-needle acupuncture was initiated, resulting in faster resolution than the first treatment. Recoveries of 50% and 75% were achieved 3 and 4 months after relapse, respectively, and a long-lasting response without relapse was obtained for at least 3 years. Conclusion A combination of multimodal traditional therapies, including JKM formulas, acupuncture, and self-administered pine-needle stimulation, represents an effective integrative treatment for patients with AA.

Background Few studies have compared the effectiveness of brief training courses on point-of-care ultrasound (POCUS) skill acquisition of novice attending physicians vs. trainees. The purpose of this study was to evaluate the change in POCUS image interpretation skills and confidence of novice attending physicians vs. trainees after a 1-day POCUS training course. Methods A 1-day POCUS training course was held in March 2017 in Japan. A standardized training curriculum was developed that included online education, live lectures, and hands-on training. The pre-course assessment tools included a written examination to evaluate baseline knowledge and image interpretation skills, and a physician survey to assess confidence in performing specific ultrasound applications. The same assessment tools were administered post-course, along with a course evaluation. All learners were novices and were categorized as trainees or attending physicians. Data were analyzed using two-way analysis of variance. Results In total, 60 learners attended the course, and 51 learners (85%) completed all tests and surveys. The 51 novice learners included 29 trainees (4 medical students, 9 PGY 1–2 residents, 16 PGY 3–5 residents) and 22 attending physicians (6 PGY 6–10 physicians, and 16 physicians PGY 11 and higher). The mean pre- and post-course test scores of novice trainees improved from 65.5 to 83.9% while novice attending physicians improved from 66.7 to 81.5% (p

Descriptive statistics and an ANOVA table of the test scores for pre- and post-course written examinations. (DOCX 19 kb)

Post-course satisfaction surveys. (DOCX 15 kb)

Analysis of variance table for pre- and post-course self-evaluation survey. (DOCX 22 kb)

Descriptive statistics for the pre- and post-course self-evaluation survey. (DOCX 19 kb)

Pre- and post-course physicians survey. (DOCX 17 kb)

Pre- and post-course written examinations. (DOCX 14 kb)

The beta-3 adrenergic receptor (ADRB3), primarily expressed in adipose tissue, is involved in the regulation of energy metabolism. The present study hypothesized that ADRB3 (Trp64Arg, rs4994) polymorphisms modulate the effects of lifestyle intervention on weight and metabolic parameters in patients with impaired glucose tolerance. Data were analyzed from 112 patients with impaired glucose tolerance in the Japan Diabetes Prevention Program, a lifestyle intervention trial, randomized to either an intensive lifestyle intervention group or usual care group. Changes in weight and metabolic parameters were measured after the 6-month intervention. The ADRB3 polymorphisms were determined using the polymerase chain reaction restriction fragment length polymorphism method. Non-carriers showed a greater weight reduction compared with the carriers in both the lifestyle intervention group and usual care group, and a greater increase of high-density lipoprotein cholesterol levels than the carriers only in the lifestyle intervention group. ADRB3 polymorphisms could influence the effects of lifestyle interventions on weight and lipid parameters in impaired glucose tolerance patients.

Background The multiple mini-interview (MMI) is increasingly used for postgraduate medical admissions and in undergraduate settings. MMIs use mostly Situational Questions (SQs) rather than Past-Behavioural Questions (PBQs). A previous study of MMIs in this setting, where PBQs and SQs were asked in the same order, reported that the reliability of PBQs was non-inferior to SQs and that SQs were more acceptable to candidates. The order in which the questions are asked may affect reliability and acceptability of an MMI. This study investigated the reliability of an MMI using both PBQs and SQs, minimising question order bias. Acceptability of PBQs and SQs was also assessed. Methods Forty candidates applying for a postgraduate medical admission for 2016–2017 were included; 24 examiners were used. The MMI consisted of six stations with one examiner per station; a PBQ and a SQ were asked at every station, and the order of questions was alternated between stations. Reliability was analysed for scores obtained for PBQs or SQs separately, and for both questions. A post-MMI survey was used to assess the acceptability of PBQs and SQs. Results The generalisability (G) coefficients for PBQs only, SQs only, and both questions were 0.87, 0.96, and 0.80, respectively. Decision studies suggested that a four-station MMI would also be sufficiently reliable (G-coefficients 0.82 and 0.94 for PBQs and SQs, respectively). In total, 83% of participants were satisfied with the MMI. In terms of face validity, PBQs were more acceptable than SQs for candidates (p = 0.01), but equally acceptable for examiners (88% vs. 83% positive responses for PBQs vs. SQs; p = 0.377). Candidates preferred PBQs to SQs when asked to choose one, though this difference was not significant (p = 0.081); examiners showed a clear preference for PBQs (p = 0.007). Conclusions Reliability and acceptability of six-station MMI were good among 40 postgraduate candidates; modelling suggested that four stations would also be reliable. SQs were more reliable than PBQs. Candidates found PBQs more acceptable than SQs and examiners preferred PBQs when they had to choose between the two. Our findings suggest that it is better to ask both PBQs and SQs during an MMI to maximise acceptability. Electronic supplementary material The online version of this article (doi:10.1186/s12909-017-0898-z) contains supplementary material, which is available to authorized users.

Objectives To examine the effects of telephone-delivered lifestyle coaching on preventing the development of type 2 diabetes mellitus (T2DM) in participants with impaired fasting glucose (IFG). Design Cluster randomised trial. Setting 40 groups from 17 healthcare divisions in Japan: companies (31), communities (6) and mixed settings (3). Participants Participants aged 20–65 years with fasting plasma glucose (FPG) of 5.6–6.9 mmol/L were invited from the 17 healthcare divisions. Randomisation The groups were then randomly assigned to an intervention or a control arm by independent statisticians according to a computer-generated list. Intervention The intervention arm received a 1-year telephone-delivered intervention provided by three private lifestyle support centres (at different frequencies: low-frequency (3 times), middle-frequency (6 times) and high-frequency (10 times) support calls). The intervention and control arms both received self-help devices such as a weight scale and pedometer. Outcomes Participants were followed up using data from annual health check-ups and a questionnaire regarding lifestyle. The primary outcome was the development of T2DM defined as FPG ≥7.0 mmol/L, the diagnosis of diabetes, or use of an antidiabetic drug, confirmed by referring to medical cards. Results Of 14 473 screened individuals, participants were enrolled in either the intervention (n=1240) arm or control (n=1367) arm. Overall, the HR for the development of T2DM in the intervention arm during 5.5 years was 1.00 (95% CI 0.74 to 1.34). In the subanalysis, the HR was 0.59 (95% CI 0.42 to 0.83) in the subgroup that received phone calls the most frequently, compared with the control arm. A limitation of the study includes a lack of blinding. Conclusions High-frequency telephone-delivered lifestyle support could effectively prevent T2DM in participants with IFG in a primary healthcare setting, although low-frequency and middle-frequency phone calls did not. Trial registration number This trial has been registered with the University Hospital Medical Information Network (UMIN000000662).