Diabetes, Prediabetes, and the Risk of a Composite Outcome of Long-term Sickness Absence and Pre-retirement Death Due to Physical Disorders.

BACKGROUND: Diabetes and prediabetes have been linked with morbidity or mortality from cardiovascular disease, cancer, or other physical disorders among working-age populations, but less is known about outcomes directly related to labor loss (eg, Tlong-term sickness absence [LTSA] or pre-retirement death due to physical disorders).This prospective study aimed to examine the association of diabetes and prediabetes with the risk of a composite outcome of LTSA and pre-retirement death due to physical disorders. The present study also examined the associations of severe outcomes (LTSA or death) due to specific physical disorders or injuries/external causes in relation to diabetes and prediabetes. METHODS: Data were derived from the Japan Epidemiology Collaboration on Occupational Health study. A total of 60,519 workers from 12 companies were followed for 8 years. Diabetes and prediabetes were defined based on the American Diabetes Association criteria. A Cox proportional hazards regression model was used to examine the association between diabetes/prediabetes and severe outcomes due to physical disorders or injuries/external causes. RESULTS: The adjusted hazard ratios of severe outcomes due to all physical disorders were 1.22 (95% confidence interval [CI], 1.02-1.45) and 2.32 (95% CI, 2.04-2.64) for prediabetes and diabetes, respectively. In cause-specific analyses, an increased risk was observed for severe outcomes due to cancers, cardiovascular diseases, diseases of the musculoskeletal system, and injuries/external causes in relation to either or both diabetes and prediabetes. CONCLUSION: Diabetes and prediabetes were associated with an increased risk of severe outcomes due to physical disorders or injuries/external causes among Japanese workers.

Metabolic syndrome and the risk of severe cancer events: a longitudinal study in Japanese workers.

BACKGROUND: Metabolic syndrome (MetS) is associated with cancer risk; however, little is known regarding its relationship with the risk of cancer-related premature death and long-term sick leave (LTSL), which can lead to a substantial loss in working years. The present study aimed to quantify the all-site and site-specific associations between MetS and the risk of severe cancer events (a composite outcome of LTSL and mortality due to cancer) in a large working population in Japan. METHODS: We recruited 70,875 workers (59,950 men and 10,925 women), aged 20-59 years, who attended health check-ups in 2011 (10 companies) and 2014 (2 companies). All workers underwent follow up for severe cancer events until March 31, 2020. MetS was defined in accordance with the Joint Interim Statement. Cox regression models were used to quantify the association between baseline MetS and severe cancer events. RESULTS: During 427,379 person-years of follow-up, 523 participants experienced the outcome consisting of 493 LTSLs of which 124 eventually resulted in death, and 30 deaths without taking LTSL. The adjusted hazard ratios (HR) (95% confidence intervals [CI]) for composite severe events due to all-site, obesity-related, and non-obesity-related cancer among those with vs. without MetS were 1.26 (1.03, 1.55), 1.37 (1.04, 1.82), and 1.15 (0.84, 1.56), respectively. In cancer site-specific analyses, MetS was associated with an increased risk of severe events due to pancreatic cancer (HR, 2.06; 95% CI, 0.99-4.26). When mortality was treated solely as the endpoint, the association was significant for all-site (HR, 1.58; 95% CI, 1.10-2.26), and obesity-related (HR, 1.59; 95% CI, 1.00-2.54) cancer. Additionally, a greater number of MetS components was associated with a greater risk of both severe cancer events and cancer-related mortality (P trend < 0.05). CONCLUSION: Among Japanese workers, MetS was associated with an increased risk of severe cancer events, especially those due to obesity-linked cancer.

Metabolic Syndrome and the Increased Risk of Medically Certified Long-term Sickness Absence: A Prospective Analysis Among Japanese Workers.

BACKGROUND: Metabolic syndrome (MetS) has been associated with various chronic diseases that may lead to long-term sickness absence (LTSA), but there is lacking information on the direct association between MetS and LTSA. The present study aimed to investigate the all-cause and cause-specific associations between MetS and the risk of medically certified LTSA among Japanese workers. METHODS: We recruited 67,403 workers (57,276 men and 10,127 women), aged 20-59 years from 13 companies in Japan during their health check-ups in 2011 (11 companies) and 2014 (2 companies), and we followed them for LTSA events (≥30 consecutive days) until March 31, 2020. MetS was defined according to the Joint Interim Statement. A Cox proportional hazards regression model was used to estimate hazard ratios (HRs) and its 95% confidence intervals (CIs) for LTSA associated with MetS and its components. RESULTS: During 408,324 person-years of follow-up, 2,915 workers experienced LTSA. The adjusted HR for all-cause LTSA was 1.54 (95% CI, 1.41-1.68) among those with MetS compared to those without MetS. In cause-specific analysis, HRs associated with MetS significantly increased for LTSA due to overall physical disorders (1.76); cardiovascular diseases (3.16); diseases of the musculoskeletal system and connective tissue (2.01); cancers (1.24); obesity-related cancers (1.35); mental, behavioral, and neurodevelopmental disorders (1.28); reaction to severe stress and adjustment disorders (1.46); and external causes (1.46). The number of MetS components were also significantly associated with increased LTSA risk. CONCLUSION: MetS was associated with an increase in the risk of LTSA due to various diseases among Japanese workers.

Image Quality and Lesion Detectability of Pancreatic Phase Thin-Slice Computed Tomography Images With a Deep Learning-Based Reconstruction Algorithm.

OBJECTIVE: To evaluate the image quality and lesion detectability of pancreatic phase thin-slice computed tomography (CT) images reconstructed with a deep learning-based reconstruction (DLR) algorithm compared with filtered-back projection (FBP) and hybrid iterative reconstruction (IR) algorithms. METHODS: Fifty-three patients who underwent dynamic contrast-enhanced CT including pancreatic phase were enrolled in this retrospective study. Pancreatic phase thin-slice (0.625 mm) images were reconstructed with each FBP, hybrid IR, and DLR. Objective image quality and signal-to-noise ratio of the pancreatic parenchyma, and contrast-to-noise ratio of pancreatic lesions were compared between the 3 reconstruction algorithms. Two radiologists independently assessed the image quality of all images. The diagnostic performance for the detection of pancreatic lesions was compared among the reconstruction algorithms using jackknife alternative free-response receiver operating characteristic analysis. RESULTS: Deep learning-based reconstruction resulted in significantly lower image noise and higher signal-to-noise ratio and contrast-to-noise ratio than hybrid IR and FBP ( P < 0.001). Deep learning-based reconstruction also yielded significantly higher visual scores than hybrid IR and FBP ( P < 0.01). The diagnostic performance of DLR for detecting pancreatic lesions was highest for both readers, although a significant difference was found only between DLR and FBP in one reader ( P = 0.02). CONCLUSIONS: Deep learning-based reconstruction showed improved objective and subjective image quality of pancreatic phase thin-slice CT relative to other reconstruction algorithms and has potential for improving lesion detectability.

Diagnostic accuracy of MRI for evaluating myometrial invasion in endometrial cancer: a comparison of MUSE-DWI, rFOV-DWI, and DCE-MRI.

OBJECTIVES: To compare the image quality of high-resolution diffusion-weighted imaging (DWI) using multiplexed sensitivity encoding (MUSE) versus reduced field-of-view (rFOV) techniques in endometrial cancer (EC) and to compare the diagnostic performance of these techniques with that of dynamic contrast-enhanced (DCE) MRI for assessing myometrial invasion of EC. METHODS: MUSE-DWI and rFOV-DWI were obtained preoperatively in 58 women with EC. Three radiologists assessed the image quality of MUSE-DWI and rFOV-DWI. For 55 women who underwent DCE-MRI, the same radiologists assessed the superficial and deep myometrial invasion using MUSE-DWI, rFOV-DWI, and DCE-MRI. Qualitative scores were compared using the Wilcoxon signed-rank test. Receiver operating characteristic analysis was performed to compare the diagnostic performance. RESULTS: Artifacts, sharpness, lesion conspicuity, and overall quality were significantly better with MUSE-DWI than with rFOV-DWI (p < 0.05). The area under the curve (AUC) of MUSE-DWI, rFOV-DWI, and DCE-MRI for the assessment of myometrial invasion were not significantly different except for significantly higher AUC of MUSE-DWI than that of DCE-MRI for superficial myometrial invasion (0.76 for MUSE-DWI and 0.64 for DCE-MRI, p = 0.049) and for deep myometrial invasion (0.92 for MUSE-DWI and 0.80 for DCE-MRI, p = 0.022) in one observer, and that of rFOV-DWI for deep myometrial invasion in another observer (0.96 for MUSE-DWI and 0.89 for rFOV-MRI, p = 0.048). CONCLUSION: MUSE-DWI exhibits better image quality than rFOV-DWI. MUSE-DWI and rFOV-DWI shows almost equivalent diagnostic performance compared to DCE-MRI for assessing superficial and deep myometrial invasion in EC although MUSE-DWI may be helpful for some radiologists.

Overtime Work and the Incidence of Long-term Sickness Absence Due to Mental Disorders: A Prospective Cohort Study.

BACKGROUND: Although previous research has focused on the association between long working hours and several mental health outcomes, little is known about the association in relation to mental health-related sickness absence, which is a measure of productive loss. We aimed to investigate the association between overtime work and the incidence of long-term sickness absence (LTSA) due to mental disorders. METHODS: Data came from the Japan Epidemiology Collaboration on Occupational Health Study (J-ECOH). A total of 47,422 subjects were followed-up in the period between April 2012 and March 2017. Information on LTSA was obtained via a study-specific registry. Baseline information was obtained at an annual health checkup in 2011; overtime working hours were categorized into <45; 45-79; 80-99; and ≥100 hours/month. RESULTS: During a total follow-up period of 211,443 person-years, 536 people took LTSA due to mental disorders. A Cox proportional hazards model showed that compared to those with less than 45 hours/month of overtime work, those with 45-79 hours/month were at a lower risk of LTSA due to mental health problems (hazard ratio [HR] 0.63; 95% confidence interval [CI], 0.56-0.71) while those with overtime work of ≥100 hours/month had a 2.11 (95% CI, 1.12-3.98) times higher risk of LTSA due to mental health problems. CONCLUSION: Engaging in excessive overtime work was linked with a higher risk of LTSA due to mental health problems while the lower risk observed among individuals working 45-79 hours/month of overtime work might have been due to a healthy worker effect.

Diagnosis-specific Cumulative Incidence of Return-to-work, Resignation, and Death Among Long-term Sick-listed Employees: Findings From the Japan Epidemiology Collaboration on Occupational Health Study.

BACKGROUND: While it is essential to understand how long is sufficient for return-to-work when designing paid sick-leave systems, little attempt has been done to collect cause-specific information on when and how many of sickness absentees returned to work, became unemployed, or passed away. METHODS: We studied the first sick-leave episode of ≥30 consecutive days in those ≤55 years of age during 2012-2013 among employees of 11 Japanese private companies (n = 1,209), which were followed until 2017. Overall and disease-specific cumulative incidences of return-to-work, resignations, and deaths were estimated using competing risk analysis. RESULTS: During the 3.5-year period (follow-up rate: 99.9%), 1,014 returned to work, 167 became unemployed, and 27 died. Overall, return-to-work occurred within 1 year in 74.9% of all absentees and in 89.3% of those who successfully returned to work. Resignation occurred within 1 year in 8.7% of all absentees and in 62.9% of all subjects who resigned. According to ICD-10 chapters, the cumulative incidence of return-to-work ranged from 82.1% for mental disorders (F00-F99) to 95.3% for circulatory diseases (I00-I99). The cumulative incidence of return-to-work due to mental disorders ranged from 66.7% in schizophrenia (F20) to 95.8% in bipolar affective disorders (F31). Death was rarely observed except for cases of neoplasms (C00-D48), of which the cumulative incidence of death reached 14.2% by 1.5 years. CONCLUSION: Return-to-work and resignations occurred commonly within 1 year of sick leave among long-term sickness absentees in the Japanese private companies. Our findings may assist occupational physicians and employers in developing effective social protection schemes.

Smoking Cessation, Weight Gain, and the Trajectory of Estimated Risk of Coronary Heart Disease: 8-Year Follow-up From a Prospective Cohort Study.

INTRODUCTION: The effect of weight gain following smoking cessation on cardiovascular risks is unclear. We aimed to prospectively investigate the association of weight gain following smoking cessation with the trajectory of estimated risks of coronary heart disease (CHD). METHODS: In a cohort of 18 562 Japanese male employees aged 30-64 years and initially free of cardiovascular diseases, participants were exclusively grouped into sustained smokers, quitters with weight gain (body weight increase ≥5%), quitters without weight gain (body weight increase <5% or weight loss), and never smokers. Global 10-year CHD risk was annually estimated by using a well-validated prediction model for the Japanese population. Linear mixed models and piecewise linear mixed models were used to compare changes in the estimated 10-year CHD risk by smoking status and weight change following smoking cessation. RESULTS: During a maximum of 8-year follow-up, both quitters with and without weight gain had a substantially decreased level of estimated 10-year CHD risk after quitting smoking, compared with sustained smokers (all ps for mean differences < .001). The estimated 10-year CHD risk within the first year after cessation decreased more rapidly in quitters without weight gain than in quitters with weight gain (change rate [95% confidence interval, CI] -0.90 [-1.04 to -0.75] vs. -0.40 [-0.60 to -0.19] % per year, p < .0001). Thereafter, the estimated 10-year CHD risk in both groups increased at similar rates (change rate [95% CI] -0.07 [-0.21 to 0.07] vs. 0.11 [-0.09 to 0.30] % per year, p = .16, from year 1 to year 2; and 0.10 [0.05 to 0.15] vs. 0.11 [0.04 to 0.18] % per year, p = .80, from year 2 to year 8). CONCLUSIONS: In this population of middle-aged, Japanese male workers, smoking cessation greatly reduces the estimated 10-year risk of CHD. However, weight gain weakens the beneficial effect of quitting smoking in a temporary and limited fashion. IMPLICATIONS: To the best of our knowledge, this study is the first to examine the effect of weight gain following smoking cessation on the trajectory of the absolute risk of CHD. Our data imply that the benefits of cessation for reducing the absolute risk of CHD outweigh the potential risk increase due to weight gain, and suggest that in order to maximize the beneficial effects of quitting smoking, interventions to control post-cessation weight gain might be warranted.

Smoking and Long-Term Sick Leave in a Japanese Working Population: Findings of the Japan Epidemiology Collaboration on Occupational Health Study.

BACKGROUND: Few studies have investigated the association between tobacco smoking and sick leave (SL) in Japan. METHODS: We followed 70 896 workers aged 20-59 years (60 133 males, 10 763 females) between April 2012 and March 2017. A Cox proportional hazards model was used to investigate the associations between smoking (smoking status and intensity) and long-term SL (ie, SL lasting ≥30 consecutive days). Cause-specific analyses were also conducted. RESULTS: A total of 1777 people took long-term SL during a follow-up of 307 749 person years. Compared with never-smokers, current smokers were at a higher risk of long-term SL (hazard ratio [HR] = 1.32; 95% confidence interval [CI] = 1.19 to 1.48). Cause-specific analyses revealed that current smoking was associated with a higher risk of SL due to all physical disorders (HR = 1.44, 95% CI = 1.22 to 1.69), cancer (HR = 1.49, 95% CI = 1.10 to 2.01), cardiovascular disease (CVD; HR = 2.16, 95% CI = 1.31 to 3.55), and injuries/external causes (HR = 1.83, 95% CI = 1.31 to 2.58). Former smokers were at a higher risk of SL due to cancer at a borderline significance level (HR = 1.38, 95% CI = 0.99 to 1.92). Low-intensity smoking (ie, 1-10 cigarettes smoked per day) was associated with all-cause SL, SL due to CVD, and SL due to injuries/external causes compared with never-smokers. CONCLUSION: In a large cohort of working-age Japanese, smoking was associated with a greater risk of long-term SL. Greater effort is needed to mitigate disease burden associated with smoking at workplace in Japan. IMPLICATIONS: Our study contributes to the literature on the association between smoking and SL in several ways. First, the study was conducted among a Japanese working population. While the association has been extensively studied in Western setting, few attempts have been made elsewhere. Second, cause-specific analyses were undertaken in our study. Third, we paid attention to the effect of low-intensity smoking on SL given that there is growing evidence of an elevated health risk associated with low-intensity smoking.

Loss of Working Life Years Due to Mortality, Sickness Absence, or Ill-health Retirement: A Comprehensive Approach to Estimating Disease Burden in the Workplace.

BACKGROUND: While much effort has focused on quantifying disease burden in occupational health, no study has simultaneously assessed disease burden in terms of mortality and morbidity. We aimed to propose a new comprehensive method of quantifying the disease burden in the workplace. METHODS: The data were obtained from the Japan Epidemiology Collaboration on Occupational Health (J-ECOH) Study, a large-scale prospective study of approximately 80,000 workers. We defined disease burden in the workplace as the number of working years lost among the working population during a 6-year period (April 2012 to March 2018). We calculated the disease burden according to consequences of health problems (ie, mortality, sickness absence [SA], and ill-health retirement) and disease category. We also calculated the age-group- (20-39 and 40-59 years old) and sex-specific disease burden. RESULTS: The largest contributors to disease burden in the workplace were mental and behavioural disorders (47.0 person-years lost per 10,000 person-years of working years; ie, per myriad [proportion]), followed by neoplasms (10.8 per myriad) and diseases of the circulatory system (7.1 per myriad). While mental and behavioural disorders made a greater contribution to SA and ill-health retirement compared to mortality, the latter two disorders were the largest contributors to the disease burden in the workplace due to mortality. The number of working years lost was greater among younger versus older female participants, whereas the opposite trend was observed in males. CONCLUSIONS: Our approach is in contrast to those in previous studies that focused exclusively on mortality or morbidity.

Comparison of HASTE with multiple signal averaging versus conventional turbo spin echo sequence: a new option for T2-weighted MRI of the female pelvis.

OBJECTIVES: This study was conducted in order to evaluate the feasibility of a newly developed half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence for T2-weighted MRI of the female pelvis, in which scanning and post-processing filtering techniques were optimized to minimize blurring and the resultant reduction in signal-to-noise ratio (SNR) was compensated by signal averaging of multiple excitations (multi-NEX), and to compare its image quality with that of a conventional turbo spin echo (TSE) sequence. METHODS: Fifty females with gynecological disease were prospectively enrolled. They underwent pelvic MRI including sagittal T2-weighted imaging obtained with multi-NEX HASTE (mHASTE) and TSE with acquisition times of 1 m 9 s and 3 m 26 s, respectively. At the prospective reading, mHASTE was reviewed first, and any changes in the image interpretation detected during the subsequent TSE reading were recorded. The SNR and tissue contrast were quantitatively measured. Two radiologists independently assessed tissue conspicuity and overall image quality considering noise, artifacts, and blurring, and visual grading characteristics (VGC) analysis was performed to compare the two sequences. RESULTS: Adding TSE to mHASTE did not change image interpretations in any case. mHASTE produced an equivalent SNR and significantly higher contrast between the myometrium and junctional zone (p < 0.05) compared with TSE. The area under the VGC curve (AUCVGC) showed that the conspicuity of the uterus, ovaries, and lesions and the overall image quality were significantly higher on mHASTE than on TSE for both readers (AUCVGC, 0.740-0.880; p < 0.01). CONCLUSION: mHASTE is a feasible option for T2-weighted MRI of the female pelvis, as it allows faster and higher-quality image acquisition than conventional TSE. KEY POINTS: • High-quality T2-weighted imaging is essential for magnetic resonance imaging of the female pelvis. • A new HASTE sequence was developed, in which a parallel imaging technique, a wide bandwidth, and a post-processing filter were used to minimize blurring, and the resultant reduction in the signal-to-noise ratio was compensated using signal averaging of multiple excitations (multi-NEX). • Multi-NEX HASTE allows fast and high-quality T2-weighted image acquisition.

Association of changes in commute mode with body mass index and visceral adiposity: a longitudinal study.

BACKGROUND: Prospective data are sparse for active commuting to work and body weight in Asia. We assessed the association of 5-year changes in commuting mode with body mass index (BMI) and the indicators of abdominal obesity in Japanese working adults. METHODS: In this longitudinal study, we studied 29,758 participants (25,808 men and 3950 women) in Japan aged 30 to 64 years at baseline who underwent further health examination 5 years after the baseline examination. Changes in BMI were calculated from objectively measured body height and weight at baseline and follow-up examination. Visceral and subcutaneous fat areas and waist circumference measured by computed tomography scans were used as indicators for abdominal adiposity. Linear regression was applied to estimate the association of changes in commuting mode with the obesity outcomes. RESULTS: Within the 5-year study period, adults who maintained inactive commuting gained weight, and compared with this group, adults who switched to inactive commuting had higher weight gain; conversely, adults who switched to active or public transportation commuting and especially those who maintained active or public transportation commuting experienced less weight gain. Subgroup analysis showed similar tendency across the different transitions of leisure-time exercise or occupational physical activity. For example, among adults who maintained no exercise (n = 16,087), the adjusted mean (95% confidence intervals) of the BMI change over 5 years in kg/m2 were 0.27 (0.24 to 0.30) for maintained inactive commuting group (reference), 0.34 (0.30 to 0.38) for switching to inactive commuting group (P = 0.046), 0.20 (0.18 to 0.22) for switching to active commuting or public transportation group (P = 0.001), and 0.09 (0.06 to 0.13) for maintained active commuting or public transportation group (P < 0.001). Maintained inactive commuting tended to be associated with larger gain in abdominal adiposity indicators. CONCLUSION: Switching from inactive commuting mode to more physically active commuting mode and maintaining active commuting can promote body weight control among working adults across different levels of occupational or leisure-time physical activity.

Patterns of changes in overtime working hours over 3 years and the risk for progression to type 2 diabetes in adults with pre-diabetes.

No information exists regarding the effects of working hours on glucose metabolism in adults with pre-diabetes, a high-risk group for developing diabetes. Further, longitudinal patterns in working hours and their effects on glucose metabolism have not been described previously. We investigated the association between changes in overtime working hours over 3 years and the risk for progression to type 2 diabetes among adults with pre-diabetes. We analyzed patterns of overtime working hours from 2008 to 2011 among 18,172 workers in Japan (16,474 men, aged 30 to 64 years) with pre-diabetes in 2011 (baseline) using the sub-cohort data from the Japan Epidemiology Collaboration on Occupational Health Study. Participants were followed up to March 2016. Overtime working hours per month were self-reported annually in 2008-2011 and trajectory patterns were identified using group-based trajectory modeling. Type 2 diabetes was diagnosed by fasting or random plasma glucose test, hemoglobin A1c, and history of diabetes. Multivariable-adjusted hazard ratios of incident diabetes were calculated using Cox regression. We identified 3 distinct trajectories of overtime work: persistently short, long-to-short, and persistently long. During a mean follow-up of 3.5 years, 1613 participants (8.9%) developed diabetes. Compared with persistently short overtime working hours, no material increase in diabetes risk was observed for either long-to-short working hours or persistently long working hours. After adjustment for potential confounders, this association was materially unchanged. The results suggest that among individuals with pre-diabetes, persistently long working hours over 3 years were not associated with an increased risk of developing type 2 diabetes.

Smoking, Smoking Cessation, and the Risk of Hearing Loss: Japan Epidemiology Collaboration on Occupational Health Study.

INTRODUCTION: We aimed to determine the prospective association of smoking status, smoking intensity, and smoking cessation with the risk of hearing loss in a large Japanese cohort. METHODS: The cohort study included 50195 employees, who were aged 20-64 years and free of hearing loss at baseline. Participants were followed up for a maximum of 8 years. Pure-tone audiometric testing was performed annually to identify hearing loss at 1 and 4 kHz. Cox proportional hazards regression models were used to investigate the association between smoking and hearing loss. RESULTS: During follow-up, 3532 individuals developed high-frequency hearing loss, and 1575 developed low-frequency hearing loss. The hazard ratio (HR) associated with current smokers was 1.6 (95% confidence interval [CI] = 1.5 to 1.7) and 1.2 (95% CI = 1.1 to 1.4) for high- and low-frequency hearing loss, respectively, as compared with never smokers. The risk of high- and low-frequency hearing loss increased with the number of cigarettes smoked per day (both p for trend <.001). The HR associated with former smokers was 1.2 (95% CI = 1.1 to 1.3) and 0.9 (95% CI = 0.8 to 1.1) for high- and low-frequency hearing loss, respectively. The analysis by quitting years showed a decline in risk of hearing loss after quitting smoking, even among those who quitted less than 5 years before baseline. CONCLUSIONS: Smoking is associated with increased risk of hearing loss, especially at the high frequency, in a dose-response manner. The excess risk of hearing loss associated with smoking disappears in a relatively short period after quitting. IMPLICATIONS: The prospective association between smoking and hearing loss has not been well studied. To the best of our knowledge, our study is the largest to date investigating the association between smoking and incident hearing loss. Our results indicate that smoking is associated with increased risk of hearing loss in a dose-response manner. Quitting smoking virtually eliminates the excess risk of hearing loss, even among quitters with short duration of cessation. These results suggest that smoking may be a causal factor for hearing loss, although further research would be required to confirm this. If so, this would emphasize the need for tobacco control to prevent or delay the development of hearing loss.

Serum cholesterol levels preceding to suicide death in Japanese workers: a nested case-control study.

OBJECTIVE: To investigate the association between suicide death and serum cholesterol levels as measured at times close to suicide death. METHODS: We conducted a nested case-control study of 41 cases of suicide deaths and 205 matched controls with serum total cholesterol (TC) levels till 3 years before suicide death in a large cohort of Japanese workers. RESULTS: Individuals in the lowest versus highest tertile/predefined category of TC in a Japanese working population had a three- to four-fold greater risk of suicide death. Each 10 mg/dl decrement of average TC was associated with an 18% increased chance of suicide death (95% confidence interval, 2-35%). Similar results were found for TC levels at each year. CONCLUSION: These results suggest that a low serum TC level in recent past is associated with an increased risk of suicide death.

Biosynthesis of Thermoresponsive Magnetic Nanoparticles by Magnetosome Display System.

Thermoresponsive magnetic nanoparticles (MNPs) were synthesized using a magnetosome display system. An elastin-like polypeptide decamer of VPGVG (ELP10), which is hydrophobic above the transition temperature ( Tt) and can form an insoluble aggregation, was immobilized on biogenic MNPs in the magnetotactic bacterium, Magnetospirillum magneticum AMB-1. It was suggested that hydrophobicity of the MNP surface increased at 60 °C compared with 20 °C by the immobilization of ELP10. Size distribution analysis indicated that the immobilization of ELP10 onto MNPs induced the increased hydrophobicity with increasing temperatures up to 60 °C, promoting aggregation of the particles by hydrophobic and magnetic interactions. These results suggest that the acceleration of magnetic collection at 60 °C was caused by particle aggregation promoted by hydrophobic interaction between ELP-MNPs. Furthermore, the immobilization of ELP on MNPs gave a quick magnetic collection at 60 °C by external magnetic field. The thermoresponsive properties will further expand the utility of biotechnological applications of biogenic MNPs.

Smoking, Smoking Cessation, and Risk of Mortality in a Japanese Working Population　- Japan Epidemiology Collaboration on Occupational Health Study.

BACKGROUND: The effect of smoking on mortality in working-age adults remains unclear. Accordingly, we compared the effects of cigarette smoking and smoking cessation on total and cause-specific mortality in a Japanese working population. Methods and Results: This study included 79,114 Japanese workers aged 20-85 years who participated in the Japan Epidemiology Collaboration on Occupational Health Study. Deaths and causes of death were identified from death certificates, sick leave documents, family confirmation, and other sources. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated via Cox proportional hazards regression. During a maximum 6-year follow-up, there were 252 deaths in total. Multivariable-adjusted HRs (95% CIs) for total mortality, cardiovascular disease (CVD) mortality, and tobacco-related cancer mortality were 1.49 (1.10-2.01), 1.79 (0.99-3.24), and 1.80 (1.02-3.19), respectively, in current vs. never smokers. Among current smokers, the risks of total, tobacco-related cancer, and CVD mortality increased with increasing cigarette consumption (Ptrend<0.05 for all). Compared with never smokers, former smokers who quit <5 and ≥5 years before baseline had HRs (95% CIs) for total mortality of 1.80 (1.00-3.25) and 1.02 (0.57-1.82), respectively. CONCLUSIONS: In this cohort of workers, cigarette smoking was associated with increased risk of death from all and specific causes (including CVD and tobacco-related cancer), although these risks diminished 5 years after smoking cessation.

Metabolic Syndrome Over 4 Years Before the Onset of Cardiovascular Disease　- Nested Case-Control Study.

BACKGROUND: We investigated the risk of cardiovascular disease (CVD) with duration of metabolic syndrome (MetS) for the past 4 years before the CVD event.Methods and Results:We performed a nested case-control study within the Japan Epidemiology Collaboration on Occupational Health Study. A total of 139 registered cases of CVD and 561 self-reported cases of CVD were identified and matched individually on age, sex, and worksite with 695 and 2,803 controls, respectively. MetS was defined by the Joint Interim Statement definition. The odds ratio (95% confidence interval) for registered CVD was 4.7 (2.9, 7.5) for people with persistent MetS (positive for MetS for ≥3 assessments) and 1.9 (1.1, 3.3) for those with intermittent MetS (positive for MetS for 1-2 assessments), compared with people without MetS during the past 4 years before the event/index date (P for trend <0.001). The corresponding odds ratio for self-reported CVD was 2.7 (2.2, 3.5) and 1.8 (1.4, 2.3) (P for trend <0.001). The association with MetS duration was stronger for myocardial infarction than for other CVD subtypes. Similar results were obtained when using the Japanese MetS criteria. CONCLUSIONS: The risk of CVD increases with increasing MetS duration. These findings contribute to risk stratification and encourage lifestyle modification for people with MetS to minimize their health risk.

Increased Incidence of Visual Field Abnormalities as Determined by Frequency Doubling Technology Perimetry in High Computer Users Among Japanese Workers: A Retrospective Cohort Study.

BACKGROUND: This retrospective cohort study primarily aimed to investigate the possible association of computer use with visual field abnormalities (VFA) among Japanese workers. METHODS: The study included 2,377 workers (mean age 45.7 [standard deviation, 8.3] years; 2,229 men and 148 women) who initially exhibited no VFA during frequency doubling technology perimetry (FDT) testing. Subjects then underwent annual follow-up FDT testing for 7 years, and VFA were determined using a FDT-test protocol (FDT-VFA). Subjects with FDT-VFA were examined by ophthalmologists. Baseline data about the mean duration of computer use during a 5-year period and refractive errors were obtained via self-administered questionnaire and evaluations for refractive errors (use of eyeglasses or contact lenses), respectively. RESULTS: A Cox proportional hazard analysis demonstrated that heavy computer users (>8 hr/day) had a significantly increased risk of FDT-VFA (hazard ratio [HR] 2.85; 95% confidence interval [CI], 1.26-6.48) relative to light users (<4 hr/day), and this association was strengthened among subjects with refractive errors (HR 4.48; 95% CI, 1.87-10.74). The computer usage history also significantly correlated with FDT-VFA among subject with refractive errors (P < 0.05), and 73.1% of subjects with FDT-VFA and refractive errors were diagnosed with glaucoma or ocular hypertension. CONCLUSIONS: The incidence of FDT-VFA appears to be increased among Japanese workers who are heavy computer users, particularly if they have refractive errors. Further investigations of epidemiology and causality are warranted.

Intensity of Leisure-Time Exercise and Risk of Depressive Symptoms Among Japanese Workers: A Cohort Study.

BACKGROUND: Data on the effect of physical activity intensity on depression is scarce. We investigated the prospective association between intensity of leisure-time exercise and risk of depressive symptoms among Japanese workers. METHODS: The participants were 29,052 employees (24,653 men and 4,399 women) aged 20 to 64 years without psychiatric disease including depressive symptoms at health checkup in 2006-2007 and were followed up until 2014-2015. Details of leisure-time exercise were ascertained via a questionnaire. Depressive states were assessed using a 13-item questionnaire. Multivariable-adjusted hazard ratio of depressive symptoms was estimated using Cox regression analysis. RESULTS: During a mean follow-up of 5.8 years with 168,203 person-years, 6,847 workers developed depressive symptoms. Compared with workers who engaged in no exercise during leisure-time (0 MET-hours per week), hazard ratios (95% confidence intervals) associated with >0 to <7.5, 7.5 to <15.0, and ≥15.0 MET-hours of leisure-time exercise were 0.88 (0.82-0.94), 0.85 (0.76-0.94), and 0.78 (0.68-0.88) among workers who engaged in moderate-intensity exercise alone; 0.93 (0.82-1.06), 0.82 (0.68-0.98), and 0.83 (0.71-0.98) among workers who engaged in vigorous-intensity exercise alone; and 0.96 (0.80-1.15), 0.80 (0.67-0.95), and 0.76 (0.66-0.87) among workers who engaged in both moderate- and vigorous-intensity exercise with adjustment for age, sex, lifestyles, work-related and socioeconomic factors, and body mass index. Additional adjustment for baseline depression score attenuated the inverse association, especially among those who engaged in moderate-intensity exercise alone. CONCLUSIONS: The results suggest that vigorous-intensity exercise alone or vigorous-intensity combined with moderate-intensity exercise would prevent depressive symptoms among Japanese workers.