Journal of Epidemiology最新文献

Background: Long-term trends in cancer incidence were reported until 2015 in Japan, but recent data have been limited since the launch of the National Cancer Registry (NCR) in 2016. We analyzed 30-year trends in cancer incidence and mortality, emphasizing the NCR's establishment.

Methods: Cancer incidence data were obtained from high-quality population-based cancer registries in three prefectures (Yamagata, Fukui, and Nagasaki) from 1985 to 2015, and the NCR extracted data from these prefectures between 2016 and 2021. National cancer mortality data from 1979 to 2023 were obtained from published vital statistics. Trends in age-standardized rates (ASR) calculated using the 1985 Japan Standard Population were examined using joinpoint regression analysis.

Results: The ASR incidence in 2016 (the first year of the NCR) was the highest ever recorded. All-cancer incidence (for both sexes) increased between 1985 and 2021 (annual percentage change, 0.9%; 95% confidence interval [95% CI]: 0.8 to 1.0). For males, all-cancer incidence stabilized after increasing until 2017, whereas for females, it increased after 2002 (1.7%; 95% CI: 1.4 to 2.3). All-cancer mortality (for both sexes) declined between 1997 and 2023 (-1.5%; 95% CI: -1.5 to -1.4), mainly due to decreases in stomach, lung, and liver cancers.

Conclusions: The NCR's launch and the sharp rise in incidence in 2016 may have influenced trend interpretation and should be considered with caution. A longer observation period is needed before clear secular trends can be established under the NCR data system.

Age-standardization is a key statistical method used in health statistics to adjust rates such as mortality or incidence, enabling comparisons across populations or time points with different age structures. This review traces its historical development, global and country-specific practices, and future directions. The method dates back to the 19th century, with major adoption in the 20th century through the Segi and Doll's World Standard Population. While the World Health Organization (WHO) introduced an updated standard in 2000, the International Agency for Research on Cancer (IARC) continues to use the Segi and Doll's standard in the Cancer Incidence in Five Continents series, prioritizing consistency and comparability in long-term cancer surveillance. Case studies from the IARC, the United States (U.S.), Japan, and the Republic of Korea (Korea) illustrate different responses to changing demographics. The U.S. adopted the 2000 standard with expanded age detail for the elderly population. Japan introduced the 2015 Japan Standard Population to account for its rapidly aging society, though regional data limitations presented challenges. Korea, experiencing one of the fastest aging transitions globally, updated to a 2020 standard for more accurate national and sub-national reporting. The review also emphasizes that age-standardization can obscure important age-specific trends. Methods like Joinpoint clustering help detect divergent trends by age groups. Looking forward, age-standardization remains essential amid global demographic shifts. However, updates of standard populations must balance improved relevance with the need for continuity and robust data. International coordination and digital tools will support more flexible and transparent health statistics in the future.

Background: In 2023, a collaborative United Nations Children's Fund-World Health Organization group introduced the concept of small vulnerable newborns (SVNs) to improve the identification of newborns at increased risk of adverse outcomes and to guide more effective preventive strategies. However, global data on the prevalence of SVNs remains scarce. This study aimed to examine secular trends in the prevalence of SVNs and their three subgroups, namely term small for gestational age (SGA), preterm SGA, and preterm non-SGA, in the Japanese population.

Methods: We analyzed data from vital statistics including livebirths and stillbirths between 1997 and 2021. Secular trends in the prevalence of SVNs and their subgroups were assessed. In addition, we conducted regional analyses to explore associations with the distribution of medical resources.

Results: A total of 26,172,760 newborns were included. The overall prevalence of SVNs was 7.8% in 1997, peaked at 8.7% in 2005, and declined to 7.7% by 2021. This decline was primarily attributed to a reduction in term SGA births. In contrast, the prevalence of preterm SGA and preterm non-SGA remained largely unchanged. In 2021, the prevalence of term SGA, preterm SGA, and preterm non-SGA was 2.0%, 0.44%, and 5.3%, respectively. No significant association was found between the regional variation in the prevalence of SVNs and the distribution of medical resources.

Conclusion: The prevalence of SVNs in Japan has declined since 2005, mainly due to reduced term SGA births. Persistent rates of preterm subgroups highlight the ongoing burden of prematurity, underscoring the need for targeted strategies to improve neonatal outcomes.

Background: A World Health Organization guideline recommends that adults engage in moderate-to-vigorous physical activity (MVPA). We aimed to clarify associations of total MVPA in any domain with overall and site-specific cancer incidence using Japanese population-based cohort data.

Methods: This study evaluated 84,054 participants (39,053 males and 45,001 females aged 50-79 years) of the 10-year survey of the Japan Public Health Center-based Prospective Study over a median follow-up of 13.0 years. Total MVPA was calculated based on a self-reported physical questionnaire, and 7.5 metabolic equivalent-hours/week (MET-hours/week) was defined as the minimum amount recommended by the guideline. Associations of categorized total MVPA with overall and site-specific cancer incidences were examined using multivariable-adjusted Cox proportional hazard models by sex.

Results: Among males, the risk reduction was non-significant even in the highest MVPA category compared with no total MVPA. Among females, in contrast, risk of total cancer was reduced even when they engaged in lower total MVPA than the recommended amount (0.1-7.4 MET-hours/week) compared with no total MVPA (hazard ratio 0.79; 95% confidence interval, 0.65-0.97), and no further risk reduction was observed with increasing MVPA. Regarding site-specific cancers, engaging in higher total MVPA was inversely associated with risks of colon cancer (males) and bladder and endometrial cancers (females).

Conclusion: Total MVPA was associated with reduced risk of overall cancer incidence in females, but not in males.

Background: Encouraging older drivers to display the older drivers' sign is one of the unique traffic safety policies for older drivers in Japan. The sign has been discussed in light of ageism, but the potential merit of displaying it has not been investigated.

Methods: Using nationwide police-reported traffic crash data, we conducted a case-control study to examine whether displaying the sign is associated with reduced rear-end collision risk among drivers aged 70 years or older who were involved in car-to-car collisions from 2014 to 2023. The cases were those involved in rear-end collisions, the controls were those involved in angle collisions, and the exposure of interest was the sign display, which should be less often observed in the cases if the sign display is effective. The association was assessed with odds ratios adjusted for the time of crash and drivers' sex and age group.

Results: Among 74,433 cases and 13,885 controls, the proportion of those displaying older drivers' signs was 38% and 39%, respectively. By the time of crash and drivers' sex and age group, the proportion tended to be slightly higher in the cases than in the controls. In both cases and controls, the proportion was higher among women, in older age groups, and during daytime. The crude and adjusted odds ratios were 0.99 (95% confidence interval [CI], 0.95-1.02) and 1.08 (95% CI, 1.04-1.12), respectively.

Conclusion: Displaying the older drivers' sign was not associated with reduced rear-end collision risk. Alternative interventions are needed to ensure their traffic safety.

Introduction: Evidence is scarce on cumulative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among healthcare workers during the pandemic. This study aimed to describe cumulative infections, including undiagnosed cases, and identify factors associated with infection in healthcare workers in Japan.

Methods: Using serosurveys conducted across six national centers in Japan, we tracked coronavirus disease 2019 (COVID-19) cumulative infections. Seropositivity was defined as a positive result for SARS-CoV-2 nucleocapsid protein using the Roche assay, and cumulative infection was defined as the proportion of participants who tested positive for anti-nucleocapsid antibodies and/or self-reported a history of laboratory-confirmed or clinically diagnosed COVID-19 since the start of the pandemic. A robust Poisson regression model was used to investigate factors associated with infection risk as of September 2023.

Results: Cumulative infection, which was less than 5% until the end of 2021, increased after the emergence of the Omicron variant. Specifically, cumulative infection reached 14.6% in July 2022 (BA.1/2), 37.4% in December 2022 (BA.5), 53.3% in September 2023 (XBB subvariants), and 71.5% in December 2023 (JN.1 subvariant). The proportion of undiagnosed cases detected by antibody testing alone, without a prior diagnosis, decreased from 60.9% in December 2020 to 24.7% in December 2023. Individuals aged 50 to 59 years (prevalence ratio [PR] 0.73; 95% confidence interval [CI], 0.67-0.79) and 60 years or older (PR 0.67; 95% CI, 0.59-0.77) had lower cumulative infections than those aged under 30 years old. Physicians and nurses had significantly higher cumulative infections than administrative staff, with fully adjusted PR of 1.09 (95% CI, 1.01-1.18) and 1.18 (95% CI, 1.08-1.30), respectively.

Conclusion: Among healthcare workers in Japan, cumulative SARS-CoV-2 infection markedly increased after the emergence of the Omicron variant, whereas the proportion of undiagnosed cases has decreased throughout the pandemic. Younger people (<50 years), as well as physicians and nurses, have faced a higher risk of infection.

Background: The coronavirus disease 2019 (COVID-19) pandemic disrupted access to healthcare for homebound older adults, particularly those with cancer. We compared changes in the initiation and outcomes of physician-led home-visit care among older Japanese patients with and without cancer during the pandemic.

Methods: We conducted a retrospective observational study using national medical claims data of patients aged ≥65 years who began physician-led home visits between April 2018 and December 2020 in Japan. The proportions of all-cause death, in-home death, and at least one hospitalization within 90 days after the initiation of home visit care were compared between the pre-pandemic (April 2018 to December 2019) and pandemic periods (January 2020 to December 2020), stratified by cancer diagnosis. Differences between the cancer and non-cancer groups were estimated using linear regression models with an interaction term for cancer status and pandemic period.

Results: Among 509,718 patients (251,311 with cancer), the initiation of home-visit care increased in both groups during the pandemic. All-cause and in-home death rates increased and hospitalization rates decreased in both groups, with greater changes among patients with cancer: 1.6% (95% confidence interval, 1.1 to 2.1) for all-cause death, 3.8% (95% CI, 3.4 to 4.3) for in-home death, and -2.9% (95% CI, -3.7 to -2.2) for hospitalization.

Conclusions: During the COVID-19 pandemic, physician-led home-visit care expanded, and patients with cancer showed a greater shift toward home-based end-of-life care. These findings highlight the need for targeted resource allocation strategies to support home-visit physicians caring for patients with cancer during public health emergencies.