Journal of EpidemiologyPub Date : 2025-06-05Epub Date: 2025-02-28DOI: 10.2188/jea.JE20240284
Midori Yamamoto, Kenichi Sakurai, Rieko Takatani, Aya Hisada, Chisato Mori
{"title":"Three-year Seroprevalence of SARS-CoV-2 Nucleocapsid Protein Antibody Among Children, Parental Awareness, and Contributors of Infection: A Single-school Cohort Study in Chiba, Japan.","authors":"Midori Yamamoto, Kenichi Sakurai, Rieko Takatani, Aya Hisada, Chisato Mori","doi":"10.2188/jea.JE20240284","DOIUrl":"10.2188/jea.JE20240284","url":null,"abstract":"<p><strong>Background: </strong>Coronavirus disease 2019 (COVID-19) in children is often asymptomatic, posing challenges in detecting infections. Additionally, factors contributing to infection remain poorly understood. This study aimed to investigate trends in anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid antibody seroprevalence, the relationship between seroprevalence and parental perception of child infection, and factors related to COVID-19 in children.</p><p><strong>Methods: </strong>In December 2020, 355 children aged 6-12 years in one elementary school were enrolled in the study. The anti-SARS-CoV-2 nucleocapsid antibody seroprevalence was assessed, and questionnaires were administered annually for 3 years. Parents' perceptions of infection and factors contributing to infection were examined.</p><p><strong>Results: </strong>The seroprevalence was 0.6%, 2.2%, and 60.9% in the first, second, and third years, respectively. The third-year seroprevalence among children reported as 'infected,' 'not tested but had symptoms,' and 'not infected' by parents was 97.3%, 83.3%, and 35.7%, respectively. Increased odds of seropositivity at the third-year measurement were observed in lower grades (adjusted odds ratio [aOR] 2.79 compared with higher grades) and in children more likely to play with others (aOR 3.97 for 'somewhat' and aOR 2.84 for 'often,' compared with 'rarely'). No significant associations with seropositivity were found for sex, siblings, body mass index, serum 25-OH vitamin D<sub>3</sub> concentration, or sleep duration.</p><p><strong>Conclusion: </strong>The Omicron variant outbreak from the end of 2021 led to a sharp increase in seroprevalence among children, with many unaware of their infection. Frequent play with others may facilitate transmission in children. These data provide useful information for developing countermeasures against COVID-19 and other future pandemics.</p>","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":"278-286"},"PeriodicalIF":3.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12066190/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142876405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Journal of EpidemiologyPub Date : 2025-06-05Epub Date: 2025-04-30DOI: 10.2188/jea.JE20240412
Akihiro Nishi, Kosuke Inoue
{"title":"What Epidemiologists Can Do in the Era of Machine Learning and Artificial Intelligence.","authors":"Akihiro Nishi, Kosuke Inoue","doi":"10.2188/jea.JE20240412","DOIUrl":"10.2188/jea.JE20240412","url":null,"abstract":"","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":"303-304"},"PeriodicalIF":3.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12066194/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142978895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuko Kadowaki, Alina V Brenner, Michiko Yamada, Hiromi Sugiyama, Mai Utada, Munechika Misumi, Ritsu Sakata
{"title":"Reproducibility of age at menarche gathered from mail questionnaires: a report from the Life Span Study.","authors":"Yuko Kadowaki, Alina V Brenner, Michiko Yamada, Hiromi Sugiyama, Mai Utada, Munechika Misumi, Ritsu Sakata","doi":"10.2188/jea.JE20250027","DOIUrl":"https://doi.org/10.2188/jea.JE20250027","url":null,"abstract":"<p><strong>Background: </strong>Menarche timing may affect female health. While previous studies evaluated self-reported age at menarche reproducibility, they did not assess types of respondents. This study compared the reproducibility of age at menarche among self-responders and proxy respondents and assessed proxy-respondent reproducibility by relationship and survey age.</p><p><strong>Methods: </strong>Data on age at menarche reported in both the 1969 and 1978 mail questionnaires among 9,043 females from the Life Span Study of atomic bomb survivors cohort were analyzed. The reproducibility of menarcheal age was assessed by the type of respondents, by proxy's relationship to participant, and by age at the 1969 survey using Bland-Altman's method and the intraclass correlation coefficient (ICC).</p><p><strong>Results: </strong>Reproducibility was moderate (95% limits of agreement: -2.3 to 2.4 years; ICC: 0.72, 95% CI, 0.71-0.73). Both self-respondents (N=6,664) and the total study population (N=9,043) maintained moderate reproducibility even at older ages. Groups with proxy reports showed lower reproducibility than self-respondents, with spouse proxy reports showing highest reproducibility and parent proxy reports showing lowest reproducibility among proxy reports, although the comparisons are based on different survey ages in 1969.</p><p><strong>Conclusion: </strong>This is the first study to evaluate menarcheal-age reproducibility between self- and proxy-reports using appropriate measures. Nine-year interval mail questionnaires showed moderate reproducibility across all ages, including elderly self-respondents. Reproducibility varied by the respondent-target relationship, with spouse proxies showing highest and parent proxies showing lowest reproducibility among proxy reports. Additional data are required to establish appropriate methods for handling specific proxy responses.</p>","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144093914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Extremely elevated high-density lipoprotein cholesterol and the risk of atrial fibrillation: the Suita Study.","authors":"Ahmed Arafa, Yuka Kato, Yoshihiro Kokubo","doi":"10.2188/jea.JE20240428","DOIUrl":"https://doi.org/10.2188/jea.JE20240428","url":null,"abstract":"","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144093893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yoshiaki Tai, Kenji Obayashi, Yuki Yamagami, Keigo Saeki
{"title":"Drowning and submersion deaths in bathtubs and associated factors: a descriptive and ecological study in Japan, 1995-2020.","authors":"Yoshiaki Tai, Kenji Obayashi, Yuki Yamagami, Keigo Saeki","doi":"10.2188/jea.JE20250032","DOIUrl":"https://doi.org/10.2188/jea.JE20250032","url":null,"abstract":"<p><p>BackgroundOlder Japanese adults have the highest drowning mortality rates globally, likely due to the in-home bathing customs. However, epidemiological evidence of preventive strategies based on national data is lacking. We aimed to describe the trends in bathtub drowning deaths (International Classification of Diseases, Tenth Revision code: W65) across Japan and explore factors that may reduce W65-coded deaths.MethodsWe collected the data of all W65-coded deaths that occurred at home from 1995 to 2020 using death certificates from the Ministry of Health, Labour, and Welfare. The national age-adjusted mortality rates (AMRs) and prefecture-specific age-standardized mortality ratios (SMRs) were calculated. Data on demographic, socioeconomic, environmental factors, and nursing care services were obtained from the Japan Portal Site of Official Statistics. Mixed-effects analysis was used to examine the association between SMR and potential contributing factors at the prefecture level.ResultsWe identified 99,930 W65-coded deaths at home, with the highest incidence among individuals aged 80-84 years, peaking in January. Since 2010, AMRs have consistently exceeded 3.0 per 100,000. An inverse association was found between SMR and the number of geriatric health service facilities and senior welfare centers per capita (coefficients per 1 standard deviation increase, -0.09 [95% confidence interval (CI), -0.13 to -0.05, P < 0.001] and -0.07 [95% CI, -0.11 to -0.02, P = 0.004]), after adjusting for demographic, socioeconomic, and environmental factors.ConclusionsSustained high AMRs suggest that the rising death toll was not solely due to aging. Increased access to nursing care facilities may help prevent W65-coded deaths.</p>","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144093954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Incidence rates of medically certified long-term sickness absence among Japanese employees: A focus on sex differences.","authors":"Yukari Taniyama, Shohei Yamamoto, Yosuke Inoue, Toru Honda, Shuichiro Yamamoto, Tohru Nakagawa, Hiroko Okazaki, Hiroshi Ide, Toshiaki Miyamoto, Takeshi Kochi, Takayuki Ogasawara, Makoto Yamamoto, Naoki Gommori, Kenya Yamamoto, Toshitaka Yokoya, Maki Konishi, Seitaro Dohi, Isamu Kabe, Tetsuya Mizoue","doi":"10.2188/jea.JE20240485","DOIUrl":"https://doi.org/10.2188/jea.JE20240485","url":null,"abstract":"<p><strong>Background: </strong>Long-term sickness absence (LTSA) is an important public health challenge, yet limited data exist on its incidence in Japan. We aimed to describe the incidence of all-cause and cause-specific LTSA by sex and age, using 10-year data from a large Japanese working population, focusing on sex differences.</p><p><strong>Methods: </strong>The study participants were employees from 16 worksites in the Japan Epidemiology Collaboration on Occupational Health Study between April 2012 and March 2022. LTSA, defined as sickness absence from work lasting 30 days or more, was recorded at each worksite. The causes of LTSA were classified using the International Classification of Diseases, 10th Revision. Incidence rates for all-cause and cause-specific LTSA were calculated based on sex and age.</p><p><strong>Results: </strong>During 730,391 and 161,513 person-years of follow-up, 6,518 and 1,866 spells of LTSA were recorded in males and females, respectively. Females had higher incidence rates of all-cause LTSA than males (115.5 vs. 89.2 per 10,000 person-years), especially among females in their 20s and 30s. This was partly attributed to younger females experiencing higher LTSA incidence rates due to mental disorders, neoplasms, and pregnancy-related illnesses. In older age, females had higher LTSA incidence rates than males for musculoskeletal diseases and injuries/external causes, whereas LTSA incidence rates due to circulatory diseases were lower than those in males.</p><p><strong>Conclusion: </strong>The incidence of total and cause-specific LTSA varied greatly by sex and age, highlighting the need to consider employees' characteristics in the prevention and management of LTSA.</p>","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144093897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tshewang Gyeltshen, Hirokazu Tanaka, Kota Katanoda
{"title":"Trends in socioeconomic inequalities in cancer screening participation before and after the COVID-19 pandemic in Japan.","authors":"Tshewang Gyeltshen, Hirokazu Tanaka, Kota Katanoda","doi":"10.2188/jea.JE20250021","DOIUrl":"https://doi.org/10.2188/jea.JE20250021","url":null,"abstract":"<p><strong>Background: </strong>Socioeconomic inequalities in cancer screening participation remain a public health issue worldwide. We assessed trends in cancer screening participation according to socioeconomic status in Japan between 2013 and 2022, considering the potential impact of the coronavirus disease 2019 (COVID-19) pandemic.</p><p><strong>Methods: </strong>Data from the nationally representative Comprehensive Survey of Living Conditions (2013-2022: approximately 500,000 persons per survey) were analyzed for age-standardized self-reported cancer screening rates for stomach, lung, colon, breast (aged 40-69 years), and cervical (aged 20-69 years) cancers, stratified by education levels. An age-adjusted Poisson model was used to assess the statistical significance of changes between the survey years.</p><p><strong>Results: </strong>A clear socioeconomic gradient was observed, particularly in stomach cancer screening, where the 2022 rates ranged from 28.3% (low education) to 58.2% (high education) for men and 20.2% to 43.2% for women, depending on education level. Between 2019 and 2022, screening rates for stomach, lung, and colorectal cancers changed by -1.2%, -0.9%, and +0.6% for men and -1.0%, +0.1%, and +1.4% for women, respectively. Breast and cervical cancer screening rates declined by 0.5% and 0.4%, respectively. The COVID-19 pandemic worsened inequalities, with a 3.1% decline in breast cancer screening among individuals with low education level, compared to a 1.0% decline among those with higher education level.</p><p><strong>Conclusions: </strong>The COVID-19 pandemic had a minor impact on screening rates (counteracting increasing trends of screening rates), except for colorectal cancer screening rates; however, the impact was relatively severe for individuals with lower socioeconomic status, especially for women.</p>","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144093917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sangjun Lee, Choonghyun Ahn, Sarah Krull Abe, Md Shafiur Rahman, Md Rashedul Islam, Eiko Saito, Seokyung An, Norie Sawada, Xiao-Ou Shu, Woon-Puay Koh, Hui Cai, Atsushi Hozawa, Seiki Kanemura, Chisato Nagata, San-Lin You, Daehee Kang, Rieko Kanehara, Yu-Tang Gao, Jian-Min Yuan, Wanqing Wen, Yumi Sugawara, Keiko Wada, Chien-Jen Chen, Keun-Young Yoo, Habibul Ahsan, Kee Seng Chia, Aesun Shin, Jeongseon Kim, Jung Eun Lee, Keitaro Matsuo, Nathaniel Rothman, You-Lin Qiao, Wei Zheng, Paolo Boffetta, Manami Inoue, Sue K Park
{"title":"Association Between Cardiometabolic Multimorbidity and 15-year Mortality in the Asia Cohort Consortium.","authors":"Sangjun Lee, Choonghyun Ahn, Sarah Krull Abe, Md Shafiur Rahman, Md Rashedul Islam, Eiko Saito, Seokyung An, Norie Sawada, Xiao-Ou Shu, Woon-Puay Koh, Hui Cai, Atsushi Hozawa, Seiki Kanemura, Chisato Nagata, San-Lin You, Daehee Kang, Rieko Kanehara, Yu-Tang Gao, Jian-Min Yuan, Wanqing Wen, Yumi Sugawara, Keiko Wada, Chien-Jen Chen, Keun-Young Yoo, Habibul Ahsan, Kee Seng Chia, Aesun Shin, Jeongseon Kim, Jung Eun Lee, Keitaro Matsuo, Nathaniel Rothman, You-Lin Qiao, Wei Zheng, Paolo Boffetta, Manami Inoue, Sue K Park","doi":"10.2188/jea.JE20240362","DOIUrl":"10.2188/jea.JE20240362","url":null,"abstract":"<p><strong>Background: </strong>Studies on the association between multimorbidity and mortality in large populations have mainly been conducted in European and North American populations. This study aimed to identify the association between cardiometabolic multimorbidity and all-cause and cardiovascular disease (CVD) mortality in the Asia Cohort Consortium.</p><p><strong>Methods: </strong>In this prospective cohort study, pooled analysis was performed to evaluate the association between cardiometabolic diseases (hypertension, diabetes, ischemic heart disease, and stroke), multimorbidity, and all-cause and CVD mortality, including premature mortality, among participants from 11 Asian cohort studies. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox hazard regression.</p><p><strong>Results: </strong>A total of 483,532 participants were followed for a median of 14.3 years. Compared with participants without any disease, those with stroke and diabetes had higher age- and sex-adjusted HRs for all-cause mortality (HR 3.9; 95% CI, 3.28-4.56). Moreover, the age- and sex-adjusted HRs for CVD mortality were highest in participants with stroke, ischemic heart disease, and diabetes (HR 10.6; 95% CI, 6.16-18.25). These patterns remained consistent after additional adjustments for smoking status and body mass index. The risk of premature mortality followed similar trends but was more pronounced.</p><p><strong>Conclusion: </strong>These findings highlight the differential impacts of individual cardiometabolic diseases and their combinations on mortality risks. Stroke and diabetes were associated with the highest risks for all-cause and cardiovascular mortality, underscoring the need for targeted prevention and personalized management strategies tailored to these high-risk conditions in Asian populations.</p>","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12162181/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144076974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Association Between Introduction of the 23-valent Pneumococcal Polysaccharide Vaccine (PPSV23) and Pneumonia Incidence and Mortality Among General Older Population in Japan: A Community-based Study.","authors":"Aya Sugiyama, Masaaki Kataoka, Kentaro Tokumo, Kanon Abe, Hirohito Imada, Bunlorn Sun, Golda Ataa Akuffo, Tomoyuki Akita, Shingo Fukuma, Noboru Hattori, Junko Tanaka","doi":"10.2188/jea.JE20240285","DOIUrl":"10.2188/jea.JE20240285","url":null,"abstract":"<p><strong>Background: </strong>With global aging, especially in Asia, preventing pneumonia among seniors is vital. The necessity of introducing pneumococcal vaccines among the elderly has been highlighted, but there is a paucity of community-based real-world evidence on their effect. Sera Town in Hiroshima Prefecture, a super-aged community, launched a distinctive pneumococcal vaccination support project for elderly residents and conducted a 5-year follow-up survey. This study evaluates the effectiveness of this vaccination initiative.</p><p><strong>Methods: </strong>From October 2010 to March 2015, Sera Town recruited elderly residents for PPSV23 vaccination with partial cost subsidies. Participants were surveyed annually for 5 years post-vaccination to assess pneumonia incidence, calculated on a person-years basis. Using vital statistics from 2000 to 2016, we quantified changes in mortality rates associated with the vaccination support project through an interrupted-time-series analysis.</p><p><strong>Results: </strong>Of approximately 7,900 residents aged 65 and older, 3,422 (43%) participated in the project (median age: 84 years; range: 70-114 years; 56.7% female). Over 14,559 person-years of observation, 295 participants developed pneumonia. The post-vaccination incidence rate was 20.3 per 1,000 person-years (95% confidence interval [CI], 18.0-22.7). Interrupted time series analysis indicated a 25% reduction in Sera Town's pneumonia mortality rate post-project, reversing an annual increase of 0.23 per 1,000 population pre-project to an annual decrease of 0.04 per 1,000 population post-project.</p><p><strong>Conclusion: </strong>This study provided real-world evidence on the association with PPSV23 vaccination on the general elderly through a community-based study. The results may be particularly useful for regions where PPSV23 serotypes are prevalent, offering insights for areas facing aging challenges.</p>","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":"237-244"},"PeriodicalIF":3.7,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11979344/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142794780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Estimating the Prevalence of and Clarifying Factors Associated With Multiple Tobacco Product Use in Japan: A Cross-sectional Study in 2022.","authors":"Takafumi Yamamoto, Hazem Abbas, Upul Cooray, Tetsuji Yokoyama, Takahiro Tabuchi","doi":"10.2188/jea.JE20240153","DOIUrl":"10.2188/jea.JE20240153","url":null,"abstract":"<p><strong>Background: </strong>Multiple tobacco product (MTP) use is a public health concern due to their combined adverse health effects. MTP use may have increased since heated tobacco products (HTPs) became more prevalent in Japan. This study aimed to (1) estimate the recent prevalence of MTP use and clarify the associated factors compared to (2) non-smokers and (3) single-product users.</p><p><strong>Methods: </strong>We used data from an internet survey conducted in February 2022. The prevalence of MTP use in Japan was estimated using inverse probability-weighted scores from this survey and a nationwide survey by the Japanese government. Tobacco products include six types: cigarettes, HTPs, e-cigarettes, cigars, pipe/water pipes, and smokeless tobacco products. MTP use was defined using the outcome variable (no use, single-product use, and MTP use) based on these six types of use. Using multivariate logistic regression, we calculated the adjusted odds ratios and 95% confidence intervals (CI) to clarify factors associated with MTP use compared to non-smokers, adjusting demographic variables, psychological distress, self-rated health, and alcohol use. Using multivariate Poisson regression, we calculated the adjusted prevalence ratios (aPRs) and 95% CIs to clarify factors associated with MTP use among smokers, adjusting for these covariates and smoking-related factors like workplace and home smoking rules.</p><p><strong>Results: </strong>We analyzed 30,141 participants whose mean age was 47.8 years (standard deviation, 17.9), and 14,722 participants were male (48.8%). The estimated prevalence of MTP use was 6.8%. The most common combination of MTP use was cigarettes and HTPs. Compared to non-smokers, being younger, male, alcohol drinkers, and having low education, poor psychological distress, and poor self-rated health were factors associated with MTP use. Among smokers, workplace smoking rules, such as a partial smoking ban and no smoking ban, were not associated with MTP use compared to the indoor smoking ban. However, having no home smoking ban was positively associated with MTP use compared with a ban on both cigarettes and HTPs at home (both cigarettes and HTPs allowed aPR 1.36; 95% CI, 1.15-1.61, HTPs only allowed aPR 1.73; 95% CI, 1.43-2.10).</p><p><strong>Conclusion: </strong>MTP users may account for a high percentage of Japanese smokers.</p>","PeriodicalId":15799,"journal":{"name":"Journal of Epidemiology","volume":" ","pages":"222-229"},"PeriodicalIF":3.7,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11979349/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142501723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}