Published papers

Background: Heated tobacco products (HTPs) have gained global popularity, but their health risks remain unclear. Therefore, the current study aimed to identify plasma metabolites associated with smoking and HTP use in a large Japanese population to improve health risk assessment.Methods: Metabolomics data from 9,922 baseline participants of the Tsuruoka Metabolomics Cohort Study (TMCS) were analyzed to determine the association between smoking habits and plasma metabolites. Moreover, alterations in smoking-related metabolites among HTP users were examined based on data obtained from 3,334 participants involved from April 2018 to June 2019 in a follow-up survey.Results: Our study revealed that cigarette smokers had metabolomics profiles distinct from never smokers, with 22 polar metabolites identified as candidate biomarkers for smoking. These biomarker profiles of HTP users were closer to those of cigarette smokers than those of never smokers. The concentration of glutamate was higher in cigarette smokers, and biomarkers involved in glutamate metabolism were also associated with cigarette smoking and HTP use. Network pathway analysis showed that smoking was associated with the glutamate pathway, which could lead to endothelial dysfunction and atherosclerosis of the vessels.Conclusion: Our study showed that the glutamate pathway is affected by habitual smoking. These changes in the glutamate pathway may partly explain the mechanism by which cigarette smoking causes cardiovascular disease. HTP use was also associated with glutamate metabolism, indicating that HTP use may contribute to the development of cardiovascular disease through mechanisms similar to those in cigarette use.

Background: Prevention of heart failure (HF) is a public health issue. Using the National Vital Statistics, we explored risk factors for HF and coronary artery disease (CAD) mortality.Methods and Results: Altogether, 7,556 Japanese individuals aged ≥30 years in 1990 were followed over 25 years; of these, 139 and 154 died from HF and CAD, respectively. In multivariable Cox proportional hazard analysis, common risk factors for CAD and HF mortality were hypertension (hazard ratio [HR] 1.48 [95% confidence interval {CI} 1.00–2.20] and 2.31 [95% CI 1.48–3.61], respectively), diabetes (HR 2.52 [95% CI 1.63–3.90] and 2.07 [95% CI 1.23–3.50], respectively), and current smoking (HR 2.05 [95% CI 1.27–3.31) and 1.86 [95% CI 1.10–3.15], respectively). Specific risk factors for CAD were male sex, chronic kidney disease, history of cardiovascular disease, and both abnormal T and Q waves, with HRs (95% CIs) of 1.75 (1.05–2.92), 1.78 (1.19–2.66), 2.50 (1.62–3.88), and 11.4 (3.64–36.0), respectively. Specific factors for HF were current drinking (HR 0.43; 95% CI 0.24–0.78) and non-high-density lipoprotein cholesterol (non-HDL-C; HR 0.81; 95% CI 0.67–0.98). There was an inverse association between non-HDL-C and HF in those aged ≥65 years (HR 0.71; 95% CI 0.56–0.90), but not in those aged <65 years.Conclusions: We identified common risk factors for HF and CAD deaths; a history of cardiovascular disease was a specific risk for CAD.

Although metabolic syndrome, including visceral fat accumulation, causes kidney and cardiovascular diseases, the impact of visceral fat accumulation on mild decreased renal function remains unclear. This study examines the association between visceral fat area (VFA) measured by bioimpedance methods and the estimated glomerular filtration rate based on serum cystatin C (eGFRcys) in the Japanese urban population. This community-based cross-sectional study enrolled 952 individuals (287 men, 665 women) who participated in the second follow-up survey of the Kobe Orthopedic and Biomedical Epidemiological (KOBE) study. We compared the multivariate-adjusted means of eGFRcys among VFA quartile groups by gender using the analysis of covariance. Models were adjusted for age, high blood pressure, hypercholesterolemia, glucose intolerance, smoking, and alcohol use, and further adjusted for body mass index (BMI). The highest VFA quartile group had lower eGFRcys than the lowest VFA quartile group after adjusted for cardiometabolic risk factors, except for BMI (93.1 [95% confidence interval (CI), 90.1–96.2] vs. 82.1 [95% CI, 79.1–85.0] in men and 95.8 [95% CI, 94.1–97.5] vs. 89.4 [95% CI, 87.8–90.9] in women). Moreover, further adjustment for BMI revealed a similar result in men (93.5 [95% CI, 89.8–97.2] vs. 81.6 [95% CI, 77.9–85.3]), while no significant association was found in women. This study suggests a significant association between increased VFA levels and lower eGFRcys levels independent of cardiometabolic risk factors, such as glucose intolerance and hypercholesterolemia in men and women, as well as independent of BMI in men.

Objective To consider effective measures against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in medical institutions, this study estimated the SARS-CoV-2 infection rate among healthcare workers (HCWs) in Tokyo, Japan, and determined the specific findings for mild coronavirus disease 2019 (COVID-19) cases. Methods This study analyzed the results of serologic tests to detect immunoglobulin G antibodies against SARS-CoV-2 and evaluated the demographic and clinical characteristics of the faculty and HCWs at a Tokyo medical institution in August 2020. The demographic and clinical characteristics of participants with antibody-positive results were compared to those of participants with antibody-negative results. Materials This study recruited 2,341 faculty and HCWs at a Tokyo medical institution, 21 of whom had a COVID-19 history. Results Of the 2,320 participants without a COVID-19 history, 20 (0.862%) had positive serologic test results. A fever and dysgeusia or dysosmia occurred with greater frequency among the participants with positive test results than in those with negative results [odds ratio (OR), 5.475; 95% confidence interval (CI), 1.960-15.293 and OR, 24.158; 95% CI, 2.693-216.720, respectively]. No significant difference was observed in the positivity rate between HCWs providing medical care for COVID-19 patients using adequate protection and other HCWs (OR, 2.514; 95% CI, 0.959-6.588). Conclusion To reduce the risk of COVID-19 spread in medical institutions, faculty and HCWs should follow standard and necessary transmission-based precautions, and those with a fever and dysgeusia or dysosmia should excuse themselves from work as soon as possible.

Objectives Though having a high salt taste threshold has been associated with hypertension, its exact determinants remains unclear. This study aimed to identify the determinants of salt taste threshold in a community-based population and to determine the relationship between salt taste thresholds and the simultaneous presence of multiple determinants.Methods Of the 1,117 participants of the baseline survey of the Kobe study, a cohort study of healthy urban residents, aged 40-74 years, with no history of cancer or cardiovascular diseases, nor undergoing treatment for hypertension, diabetes, or dyslipidemia, was conducted. Among them, 1,116 underwent the salt taste threshold test, and urine samples were collected to determine their estimated salt intake. The salt taste threshold test was carried out using SALSAVE®, with a salt taste threshold of 0.6% defined as normal, and that of 0.8% or more defined as high. A binomial logistic regression model was used, with high salt taste threshold as the objective variable, and life and family status, education, smoking and alcohol drinking status, intake status of salt dried fish, stress indicators, and daily salt intake (estimated from the urine sample) as the explanatory variables. A binomial logistic regression analysis was conducted, through multivariate analysis using the forced entry method, with factors influencing salt taste threshold as explanatory variables, and salt taste threshold (normal/high) as the objective variable. This analysis was performed excluding the urinary sodium-to-potassium ratio to account for multicollinearity with the estimated daily salt intake.Results The mean age was 60.9±9.0 years for men, and 58.0±8.7 years for women. The salt taste threshold was normal in 80.9% (n=903) of the participants (73.6% [n=251] men and 84.1% [n=652] women), and high in 19.1% (n=213) of the participants (26.3% [n=90] men and 15.9% [n=123] women). Multivariate analysis revealed that smoking habits were significantly associated with a higher salt taste threshold, with an odds ratio (95% confidence interval) of 2.51 (1.33-4.74) for all participants. The odds ratio for a high salt taste threshold was 1.45 (1.03-2.03) for the top 25% estimated daily salt intake group, showing a significant association with a high salt taste threshold. In the analysis by sex, smoking habits were associated with higher salt taste thresholds, while an association with estimated daily salt intake was observed only in men.Conclusion Smoking status and estimated daily salt intake were associated with higher salt taste thresholds in healthy urban residents.