Published papers

Background: Heated tobacco product (HTP) use in Japan has rapidly increased. Despite this rapid spread, little is known about the health effects of HTP use. We conducted a longitudinal cohort study to investigate the change in smoking habits following the spread of HTP use and its effect on forced expiratory volume in one second (FEV1) decline.Methods: Participants consisted of a resident population (n=2,612, aged 67.7) with FEV1 measurement in 2012-2014 and 2018-2019, and a worksite population (n=722, aged 49.3) without FEV1 data. Participants were categorized as never, past and combustible cigarette-only smokers, and HTP-only and dual users. The association between smoking group and the change in smoking consumption for 5.6 years was examined. Differences in annual FEV1 change between smoking groups were examined in the resident population.Results: Prevalence of HTP-only and dual users in 2018-2019 was 0.8% and 0.6% in the resident population, and 5.0% and 1.9% in the worksite population, respectively. The overall number of tobacco products smoked/used increased in dual users compared to baseline, but not in others. Annual FEV1 decline in dual users tended to be greater than that in cigarette-only smokers (16 mL/yr [95% CI: -34, 2] after full adjustment). Participants switching to HTP-only use 1.7 years before had a similar FEV1 decline as cigarette-only smokers.Conclusions: HTP use, including dual use, is prevalent even in a rural region of Japan. Dual users appear to smoke/use tobacco products more and have a greater FEV1 decline. Tobacco policy should consider dual use as high-risk.

Aims: The categories in the comprehensive lipid and risk management guidelines were proposed by the Japan Atherosclerosis Society (JAS Guidelines 2017), which adopted the estimated 10 year absolute risk of coronary artery disease (CAD) incidence in the Suita score. We examined whether those categories were concordant with the degree of arterial stiffness. Methods: In 2014, the cardio-ankle vascular index (CAVI), an arterial stiffness parameter, was measured in 1,972 Japanese participants aged 35–74 years in Tsuruoka City, Yamagata Prefecture, Japan. We examined the mean CAVI and the proportion and odds ratios (ORs) of CAVI ≥ 9.0 on the basis of the following three management classifications using the analysis of variance and logistic regression: "Category I (Low risk)," "Category II (Middle risk)," and "Category III (High risk)." Results: The mean CAVI and proportion of CAVI ≥ 9.0 were 8.6 and 34.8% among males and 8.1 and 18.3% among females, respectively. The mean CAVI and proportion of CAVI ≥ 9.0 were associated with an estimated 10 year absolute risk for CAD among males and females, excluding High risk for females. These results were similar to the management classification by the guideline: the multivariable-adjusted ORs (95% confidence intervals) of CAVI ≥ 9.0 among Category II and Category III compared with those among Category I were 2.96 (1.61–5.43) and 7.33 (4.03–13.3) for males and 3.99 (2.55–6.24) and 3.34 (2.16–5.16) for females, respectively. Conclusions: The risk stratification, which was proposed in the JAS Guidelines 2017, is concordant with the arterial stiffness parameter.

BackgroundElevated resting heart rate (RHR) is associated with an increased risk for cardiovascular disease (CVD) and all-cause mortality. However, the findings of cohort studies differed. Thus, the impact of RHR on CVD mortality might be different according to the background of the population. Therefore, we examined the relationship of RHR and CVD mortality according to serum ALB levels in a Japanese general population.MethodsIn total, 8363 individuals without a history of CVD were followed-up for 24.0 years. The participants were divided into four groups according to the quartiles of RHR (Q1–Q4), and they were further classified into the high and low ALB groups based on a median value of 44 g/L. We estimated the multivariable-adjusted hazard ratios (HRs) of CVD mortality in each RHR group based on ALB levels, and the interaction between RHR and ALB groups on CVD mortality was evaluated.ResultsWe found no significant association between RHR and CVD mortality. However, the Q4 of RHR was significantly associated with an increased risk for CVD mortality (HR: 1.27 [95% confidence interval, CI: 1.02–1.57]) in participants with a low ALB level. Meanwhile, the Q4 of RHR was significantly correlated with a decreased risk for CVD morality in those with a high ALB level (HR: 0.61 [95% CI: 0.47–0.79]) after adjusting for covariates. A significant interaction between RHR and ALB for CVD mortality was shown (p<0.001).ConclusionsThe impact of RHR on CVD mortality differed according to ALB levels in a general Japanese population.

Background: Non-fasting triglycerides (TG) are considered a better predictor of cardiovascular disease (CVD) than fasting TG. However, the effect of non-fasting TG on fatal CVD events remains unclear. In the present study, we aimed to explore the relationship between non-fasting TG and CVD mortality in a Japanese general population.Methods: A total of 6,831 participants without a history of CVD, in which those who had a blood sampling over 8 hours or more after a meal were excluded, were followed for 18.0 years. We divided participants into seven groups according to non-fasting TG levels: ≤59 mg/dL, 60–89 mg/dL, 90–119 mg/dL, 120–149 mg/dL, 150–179 mg/dL, 180–209 mg/dL, and ≥210 mg/dL, and estimated the multivariable-adjusted hazard ratios (HRs) of each TG group for CVD mortality after adjusting for potential confounders, including high density lipoprotein cholesterol. Additionally, we performed analysis stratified by age <65 and ≥65 years.Results: During the follow-up period, 433 deaths due to CVD were detected. Compared with a non-fasting TG of 150–179 mg/dL, non-fasting TG ≥210 mg/dL was significantly associated with increased risk for CVD mortality (HR 1.56: 95% CI, 1.01–2.41). Additionally, lower levels of non-fasting TG were also significantly associated with increased risk for fatal CVD. In participants aged ≥65 years, lower levels of non-fasting TG had a stronger impact on increased risk for CVD mortality, while higher levels of non-fasting TG had a stronger impact in those aged <65 years.Conclusion: In a general Japanese population, we observed a U-shaped association between non-fasting TG and fatal CVD events.

Objective　To explore health-related and socioeconomic factors that can predict future deterioration in Psychological Distress Scale (K6) scores.Method　We conducted a baseline (2010, 2011) self-administered questionnaire survey of the Kobe Orthopedic and Biomedical Epidemiological study (KOBE study) involving 1,117 participants who had no previous history of cancer or cardiovascular diseases and were not under treatment for hypertension, diabetes, or dyslipidemia. We used the Japanese K6 as an indicator of stress and defined K6≧5 points as a high-stress group and K6<5 points as a low-stress group. A four-year follow-up survey (2014, 2015) was conducted on 1,004 people (follow-up rate of 90%). We excluded 39 participants with missing values, and 185 people whose K6 score was higher than 5 points at baseline. A final total of 780 participants' scores were examined for: gender, age, living situation, physical activity level, average sleep time, as well as the K6 score, the Japanese Hearing Handicap Inventory for Elderly (HHIE-S), and the Japanese Oswestry Disability Index (ODI). We conducted a logistic regression analysis using K6≧5 points at the four-year follow-up survey as the dependent variable and each factor at the baseline survey as the independent variable.Results　Of the 780 subjects analyzed, 132 (16.9%) were highly stressed (K6≧5 points) at the four-year follow-up point. A logistic regression analysis found age (40s/70s) (odds ratio 3.38, 95% confidence interval 1.45-7.86), living situation (single/living together) (odds ratio 1.98, 95% confidence interval 1.07-3.68), and ODI scores (every 1%) (odds ratio 1.05, 95% confidence interval 1.01-1.09), to all be significantly associated with high stress.Conclusion　This study suggests that age, living situation, and ODI scores are related to future stress.

Aims: P-wave terminal force in lead V1 (PTFV1) is an electrocardiogram marker of increased left atrial pressure and may be a noninvasive and early detectable marker for future cardiovascular events in the general population compared to serum B-type natriuretic peptide (BNP) concentration. The clinical significance of PTFV1 in the contemporary general population is an area of unmet need. We aimed to demonstrate the correlation between PTFV1 and BNP concentrations in a contemporary representative Japanese population. Methods: Among 2,898 adult men and women from 300 randomly selected districts throughout Japan (NIPPON DATA2010), we analyzed 2,556 participants without cardiovascular disease (stroke, myocardial infarction, and atrial fibrillation). Elevated BNP was defined as a value of ≥ 20 pg/mL based on the definition from the Japanese Circulation Society guidelines. Results: In total, 125 (4.9%) participants had PTFV1. Participants with PTFV1 were older with a higher prevalence of hypertension, major electrocardiographic findings, and elevated BNP concentrations (13.5 [6.9, 22.8] versus 7.8 [4.4, 14.5] pg/mL; P＜0.001). After adjustment for confounders, PTFV1 was correlated with elevated BNP (odds ratio, 1.66; 95% confidence interval, 1.05–2.62; P=0.030). This correlation was consistent among various subgroups and was particularly evident in those aged ＜65 years or those without a history of hypertension. Conclusions: In the contemporary general population cohort, PTFV1 was independently related to high BNP concentration. PTFV1 may be an alternative marker to BNP in identifying individuals at a higher risk of future cardiovascular events in the East Asian population.

Aim: This study investigated the relationship between birth physique and cardiovascular risk factors in Japanese urban residents aged 40 years and more. Methods: A self-administered questionnaire on birth physique was performed among 624 individuals (165 men and 459 women) who participated in the KOBE study. We examined whether self-reported birth physique and available recorded birth weights matched for 72 participants. Then the association between birth physique and risk factors for all participants was examined by gender. Body size at birth in the questionnaire (large, medium, small) was set as an exposure and laboratory values from the baseline survey (2010-2011) were used as outcomes. Results: Mean (standard deviation) recorded birth weight of 72 participants was 3665 (318), 3051 (300), and 2653 (199) g, in the large, medium, and small group, respectively. In the analysis for all participants, odds ratio for having both hypertension and impaired glucose tolerance were significantly higher in the small versus large birth weight group, which was 7.42 (95% CI 1.75–31.50) for men and 4.44 (95% CI 1.14–17.30) for women after adjusting for age, body mass index, smoking/alcohol/exercise habits, and menstrual status in women. Similar results were observed in participants with recorded birth weight. Conclusions: The present study indicates that individuals with small physique at birth might be at higher risk for hypertension and impaired glucose tolerance in middle age compared to those with large birth weight.

Background: Although self-reported questionnaires are widely employed in epidemiologic studies, their validity has not been sufficiently assessed. The aim of this study was to evaluate the validity of a self-reported questionnaire on medication use by comparison with health insurance claims and to identify individual determinants of discordance in the Tsuruoka Metabolomics Cohort Study.Methods: Participants were 2,472 community-dwellers aged 37 to 78 years from the Tsuruoka Metabolomics Cohort Study. Information on lifestyle and medications was collected through a questionnaire. Sensitivity and specificity were determined using health insurance claims from November 2014 to March 2016, which were used as a standard. Potential determinants of discordance were assessed using multivariable logistic regression.Results: The self-reported questionnaire on medication use showed high validity. Sensitivity and specificity were 0.95 (95% CI, 0.93–0.96) and 0.97 (95% CI, 0.96–0.98) for antihypertensive medications, 0.94 (95% CI, 0.91–0.97) and 0.98 (95% CI, 0.98–0.99) for diabetes medications, and 0.84 (95% CI, 0.82–0.87) and 0.98 (95% CI, 0.97–0.99) for dyslipidemia medications, respectively. Males without high education and those who currently smoke cigarettes were found to be associated with discordant reporting which affected sensitivity, especially those with medication use for dyslipidemia.Conclusions: In this population-based cohort study, we found that the self-reported questionnaire on medication use was a valid measure to capture regular medication users. Sensitivity for dyslipidemia medications was lower than those for the other medications. Type of medication, sex, education years, and smoking status influenced discordance, which affected sensitivity in self-reporting.

© 2018 National Lipid Association Background: The effect of very high or extremely high levels of high-density lipoprotein cholesterol (HDL-C) on cardiovascular disease (CVD) is not well described. Although a few recent studies have reported the adverse effects of extremely high levels of HDL-C on CVD events, these did not show a statistically significant association between extremely high levels of HDL-C and cause-specific CVD mortality. In addition, Asian populations have not been studied. Objective: We examine the impact of extremely high levels of HDL-C on cause-specific CVD mortality using pooled data of Japanese cohort studies. Methods: We performed a large-scale pooled analysis of 9 Japanese cohorts including 43,407 participants aged 40–89 years, dividing the participants into 5 groups by HDL-C levels, including extremely high levels of HDL-C ≥2.33 mmol/L (≥90 mg/dL). We estimated the adjusted hazard ratio of each HDL-C category for all-cause death and cause-specific deaths compared with HDL-C 1.04–1.55 mmol/L (40–59 mg/dL) using a cohort-stratified Cox proportional hazards model. Results: During a 12.1-year follow-up, 4995 all-cause deaths and 1280 deaths due to overall CVD were identified. Extremely high levels of HDL-C were significantly associated with increased risk of atherosclerotic CVD mortality (hazard ratio = 2.37, 95% confidence interval: 1.37–4.09 for total) and increased risk for coronary heart disease and ischemic stroke. In addition, the risk for extremely high HDL-C was more evident among current drinkers. Conclusion: We showed extremely high levels of HDL-C had an adverse effect on atherosclerotic CVD mortality in a pooled analysis of Japanese cohorts.

© 2018 The Japan Society of Hepatology Aim: Fatty liver is associated with the development of diabetes. However, to our knowledge, no study has examined the relationship between the fatty liver index (FLI), calculated scores of hepatic steatosis, and the development of diabetes among individuals without impaired fasting glucose (IFG). We aimed to examine whether FLI predicts the development of diabetes in individuals with and without IFG in a Japanese general population. Methods: We selected 1498 men and 2941 women who participated in Specific Health Checkups in Japan. We divided all participants into six groups according to tertiles of FLI (low, moderate, and high) and the presence or absence of IFG, by sex. We calculated hazard ratios for incident diabetes for each group using a Cox proportional hazard model, adjusting for potential confounders. Results: During a mean follow-up period of 3.0 years, 176 cases of diabetes in men and 320 cases in women were identified. Compared with the low FLI group without IFG, the high FLI group without IFG was significantly associated with incident diabetes in both men (hazard ratio, 1.90; 95% confidence interval, 1.08–3.36) and women (hazard ratio, 1.72; 95% confidence interval, 1.18–2.51). All IFG groups were significantly associated with incident diabetes regardless of FLI levels. Conclusions: Our results showed that FLI is associated with the development of diabetes regardless of sex and the presence or absence of IFG, and that it may be a useful predictor of future risk of incident diabetes even in individuals without IFG.

© 2019 The Author(s). Background: Although several epidemiological studies have suggested that high serum uric acid (SUA) levels are related to a decline in kidney function, only a few studies have investigated using cystatin C to calculate estimated glomerular filtration rate (eGFR). We aimed to clarify the relationship between SUA levels and kidney function assessed by cystatin C in a Japanese general community population without chronic kidney disease (CKD). Methods: We conducted a community-based cross-sectional study that included 1086 healthy participants, aged 40-74 years, without CKD and not undergoing treatment of hyperuricemia, who had participated in the baseline survey of the Kobe Orthopedic and Biomedical Epidemiological (KOBE) study. The preconditions for participation in this study were no past histories of cardiovascular disease or cancer, and not undergoing treatment for diabetes, hypertension, or dyslipidemia. We classified the participants into quartiles stratified by sex according to their SUA level and then examined the relationship with eGFR. The odds ratios for having a low eGFR, defined as the lowest quartile of eGFR (i.e., ≤78.4 mL/min/1. 73m 2 ) was estimated according to SUA quartiles (men, Q1 ≤ 5.0, Q2 5.1-5.9, Q3 6.0-6.6, and Q4 ≥ 6.7; women, Q1 ≤ 3.8, Q2 3.9-4.3, Q3 4.4-4.9, and Q4 ≥ 5.0 mg/dL) after adjustment for age, body mass index, systolic blood pressure, HbA1c, high and low density lipoprotein cholesterol, and smoking and drinking habits. The adjusted mean of each quartile was also calculated. Results: Multivariable-adjusted means of eGFR showed a graded decrease in higher SUA quartiles (men, Q1 90.5, Q2 88.0, Q3 83.5, and Q4 82.0; women, Q1 95.7, Q2 91.3, Q3 89.2, and Q4 86.7). In addition, the multivariable-adjusted odds ratios for having a lower eGFR (95% confidence interval) for each SUA quartile compared with Q1 was Q2 2.29 (0.98, 5.35), Q3 4.94 (2.04, 11.97), and Q4 8.01 (3.20, 20.04) for men, and was Q2 2.20 (1.12, 4.32), Q3 2.68 (1.39, 5.20), and Q4 4.96 (2.62, 9.41) for women. Conclusions: There was a graded inverse relationship between mild elevations in SUA levels and eGFR assessed by cystatin C in an apparently healthy Japanese population without CKD. This association was similar in both men and women.

© 2016 European Society of Cardiology. Background Studies have shown significant associations of chronic kidney disease (CKD) and diabetes mellitus (DM) with cardiovascular disease (CVD) mortality. The impact on the general population is an important public health issue. However, the population attributable fraction (PAF) of CVD because of CKD and/or DM in a general population is uncertain. Methods We followed 7229 participants (age: ≥30 years) with no history of CVD in a Japanese community. We divided participants into four categories according to CKD and/or DM and calculated hazard ratios (HRs) of CVD mortality for each category using a Cox proportional hazards model adjusted for age, dyslipidemia, smoking and alcohol consumption. In addition, PAFs of CVD were estimated among populations with CKD and/or DM. Results During 20-year follow-up, 488 participants died. HRs for CVD were 1.63 [95% confidence interval (CI): 1.16-2.30] with DM only, 1.42 (95% CI: 1.08-1.86) with CKD only and 2.37 (95% CI: 1.40-4.01) with CKD + DM. In men, the corresponding HRs for CVD were 1.88 (95% CI: 1.19-2.97), 1.71 (95% CI: 1.15-2.56) and 3.26 (95% CI: 1.69-6.30), respectively; the corresponding PAFs of CVD were 4.1%, 5.1% and 2.9%, respectively. PAFs for CVD among women were lower than those in men, 1.6% for DM only, 2.0% for CKD only and 0.7% for CKD + DM. Conclusions PAFs of CVD mortality due to CKD and/or DM were not so high in past 20 years; however, they might increase in the future because of recent increase in prevalence of these in Japanese population.

© 2016 The Japan Society of Hepatology Aim: Surveillance is recommended for patients with risk of hepatocellular carcinoma (HCC) such as viral hepatitis and liver cirrhosis (LC). Although populations are at higher risk in Asia, surveillance rates have not been evaluated in those countries. Therefore, we aimed to examine surveillance rates for HCC and to compare predictors for surveillance among each type of liver disease in Japan. Methods: We carried out an observational study using the medical claims data of Japan. A total of 4713 patients who were diagnosed with LC, hepatitis B virus (HBV), or hepatitis C virus (HCV) infection were followed for 12 months. We described surveillance rates in patients with HBV or HCV infection or non-viral LC and evaluated potential predictors for follow-up surveillance among them by using multivariable logistic regression analysis, in which we set explanatory variables as sex, age, medical facility, HBV or HCV infection, and LC. Results: The HCC surveillance rate during follow-up was 42.3% among patients with chronic viral hepatitis, 56.5% with viral cirrhosis and 26.0%, with non-viral LC. Significant predictors for follow-up surveillance were presence of LC and hospital visits. Hepatitis B virus-infected patients aged <50 years and HCV-infected patients aged ≥50 years were more likely to undergo exams, that is, different tendencies between HBV and HCV patients were shown. Conclusions: Follow-up surveillance for HCC was not adequately carried out among patients at risk for HCC in Japan, despite of recommendation in guidelines. In future, methodological research might be needed to increase surveillance rates for HCC in patients with chronic hepatitis or those who received treatment at a clinic.

© 2016, Japan Atherosclerosis Society. All rights reserved. Aims: There is no community-based cohort study to examine the effect of very high level of highdensity lipoprotein cholesterol (HDL-C) on coronary heart disease (CHD) and other cause-specific mortality. Therefore, we investigated the relationship between HDL-C including very high level and cause-specific mortality in a 20-year cohort study of the representative sample of Japanese. Methods: We followed 7,019 individuals from the Japanese general population (2,946 men and 4,073 women). We defined HDL-C levels as follow: low (HDL-C <1.04 mmol/L), reference (1.04-1.55 mmol/L), high (1.56- 2.06 mmol/L), very high (≥2.07 mmol/L). The multivariate adjusted hazard ratio (HR) for all-cause or cause-specific mortality was calculated using a Cox proportional hazards model adjusted for other traditional risk factors. Results: During follow-up, we observed 1,598 deaths. No significant association was observed between HDL-C and all-cause mortality. Serum HDL-C also showed no association with stroke. In contrast, the risk for CHD among high HDL-C was lower than reference, HRs were 0.51 [95% confidence interval (CI): 0.21-1.23] in men, 0.33 (95% CI: 0.11-0.95) in women, and 0.41 (95% CI: 0.21 -0.81) when men and women were combined. However, very high HDL-C did not show significant association with CHD and other cause-specific mortality. Conclusions: HDL-C was not associated with all-cause and stroke mortality. In contrast, high serum HDL-C levels, at least up to 2.06 mmol/L, were protective against CHD, although further high levels were not. However, sample size of cause-specific death in very high HDL-C group was not enough even in this 20-year follow-up of 7,019 Japanese; larger cohort studies should be warranted.

© 2019 by Asian Journal of Atmospheric Environment. The island of Miyakejima in Japan is subject to ongoing emissions of volcanic gases, including high concentrations of sulfur dioxide (SO2). Annual health checkups on the island, therefore, include the examination of respiratory system parameters. Here, we aimed to investigate the relationship between SO2 exposure and fractional exhaled nitric oxide (FeNO) concentration among children who received health checkups from 2008 to 2014. The subjects were 83 and 31 second-year junior high school students aged 13-14 years who resided on Miyakejima island and an SO2-free reference island, respectively. SO2 concentration in the air was measured at 6 fixed-point monitoring stations. FeNO was examined according to the American Thoracic Society guideline and European Respiratory Society recommendations for standardized procedures. Average concentrations of SO2 on Miyakejima over a period of 3 months prior to each health checkup from 2008 to 2014 were 22.2, 20.6, 8.9, 10.5, 10.7, 4.4 and 8.0 ppb, respectively. Among the Miyakejima students, geometric mean (GM) FeNO concentrations measured at each health checkup from 2008 to 2014 were 28.2, 18.2, 23.6, 35.5, 36.9, 28.1, and 32.1 ppb. The GM FeNO concentration measured from all Miyakejima students across the study period was 28.3 ppb. No clear dose-response relationship was observed. The GM FeNO concentration among the students from the reference island was 27.7 ppb in 2017. No significant difference was observed between the two populations, even when the data was stratified by sex and sensitivity. There was no clear significant difference in GM of FeNO concentration between Miyakejima and control students, when the average concentration of SO2 over a period of 3 months was 22 ppb or less.