Effectiveness of self-sampling human papillomavirus test on precancer detection and screening uptake in Japan: The ACCESS randomized controlled trial.

Japan is lagging in cervical cancer prevention. The effectiveness of a self-sampling human papillomavirus (HPV) test, a possible measure to overcome this situation, has not yet been evaluated. A randomized controlled trial was performed to evaluate the effectiveness of a self-sampling HPV test on detection of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and screening uptake. Women between 30 and 58 years old who did not participate in the cervical cancer screening program for ≥3 years were eligible and assigned to the intervention group (cytology or self-sampling HPV test) or control group (cytology). Participants assigned to the intervention group were sent a self-sampling kit according to their ordering (opt-in strategy). A total of 7337 and 7772 women were assigned to the intervention and control groups, respectively. Screening uptake in the intervention group was significantly higher than that in the control group (20.0% vs. 6.4%; risk ratio: 3.10; 95% confidence interval [CI]: 2.82, 3.42). The compliance rate with cytology triage for HPV-positive women was 46.8% (95% CI: 35.5%, 58.4%). CIN2+ was detected in five and four participants in the intervention and control groups, respectively; there was no difference for intention-to-screen analysis (risk ratio: 1.32; 95% CI: 0.36, 4.93). Self-sampling of HPV test increased screening uptake; however, no difference was observed in the detection of CIN2+, probably due to the low compliance rate for cytology triage in HPV-positive women. Efforts to increase cytology triage are essential to maximize precancer detections.

Impact of the coronavirus disease 2019 pandemic on primary and metastatic lung cancer treatments in Japan: A nationwide study using an interrupted time series analysis.

BACKGROUND: The coronavirus disease 2019 pandemic prompted healthcare providers to use different approaches from the current standards of care. We aimed to identify the changes in the number of treatments for primary non-small cell lung cancer (NSCLC) and metastatic lung cancer during the pandemic. METHODS: We used nationwide insurance claims data from January 2015 to January 2021, and estimated changes in the number of treatments using an interrupted time series analysis. RESULTS: The number of surgical resections for primary NSCLC significantly decreased in April 2020 (-888; 95% confidence interval [CI]: -1530 to -246) and July 2020 (-1314; 95% CI: -1935 to -694), while the number of stereotactic body radiotherapies (SBRTs) increased in April 2020 (95; 95% CI: 8-182) and July 2020 (111; 95% CI: 24-198). The total number of treatments for primary NSCLC remained unchanged; however, non-significant decreases were observed in 2020. The number of surgical resections for metastatic lung cancer significantly decreased in April 2020 (-201; 95% CI: -337 to -65), but it eventually increased in July 2020 (170; 95% CI: 32-308). Additionally, the number of SBRTs significantly increased in April 2020 (37; 95% CI: 3-71) and October 2020 (57; 95% CI: 23-91). The total number of treatments for metastatic lung cancer was maintained, with an initial decrease in April 2020 followed by a subsequent increase in July and October 2020. CONCLUSION: In Japan, surgical triage for primary and metastatic lung cancer are likely to have been implemented during the pandemic. Despite these proactive measures, patients with primary NSCLC may have been untreated, likely owing to their undiagnosed disease, potentially leading to a deterioration in prognosis. By contrast, patients diagnosed with cancer prior to the pandemic are presumed to have received standard management throughout the course of the pandemic.

Impact of the COVID-19 pandemic on gastric surgery in Japan: A nationwide study using interrupted time-series analyses.

BACKGROUND AND AIM: Changes in the number of surgeries for gastric cancer during the coronavirus disease 2019 (COVID-19) pandemic have been reported, but data are insufficient to understand the impact at the national level. This study aimed to determine the impact of the COVID-19 pandemic on gastric surgery in Japan. METHODS: Insurance claims data registered from January 2015 to January 2021 were used. Changes in the number of endoscopic resections and gastrectomies for gastric cancer were estimated using an interrupted time-series analysis. RESULTS: The number of endoscopic resections significantly decreased in July 2020 (-1565; 95% confidence interval [CI]: -2022, -1108) and January 2021 (-539; 95% CI: -970, -109), and the number of laparoscopic surgeries significantly decreased in July 2020 (-795; 95% CI: -1097, -492), October 2020 (-313; 95% CI: -606, -19), and January 2021 (-507; 95% CI: -935, -78). Meanwhile, the number of open gastrectomies remained unchanged, and the number of robot-assisted gastrectomies steadily increased since their coverage by public health insurance in April 2018. CONCLUSIONS: The decreased number of endoscopic resections and laparoscopic surgeries in Japan suggests a decline in early-stage gastric cancer diagnosis, likely due to the suspension of gastric cancer screening and diagnostic testing during the pandemic. Meanwhile, the number of open and robot-assisted gastrectomies remained unchanged and increased, respectively, indicating that these applications were not affected by the pandemic-related medical crisis. These findings highlight that procedures for cancer diagnosis, including screening, should still be provided during pandemics.

Acceptability of self-sampling human papillomavirus test for cervical cancer screening in Japan: A questionnaire survey in the ACCESS trial.

PURPOSE: In terms of medical policy for cervical cancer prevention, Japan lags far behind other industrialized countries. We initiated a randomized controlled trial to evaluate the self-sampling human papillomavirus (HPV) test as a tool to raise screening uptake and detection of pre-cancer. This study was conducted to explore the acceptability and preference of self-sampling using a subset of the data from this trial. METHODS: A pre-invitation letter was sent to eligible women, aged 30-59 years who had not undergone cervical cancer screening for three or more years. After excluding those who declined to participate in this trial, the remaining women were assigned to the self-sampling and control groups. A second invitation letter was sent to the former group, and those wanting to undergo the self-sampling test ordered the kit. A self-sampling HPV kit, consent form, and a self-administered questionnaire were sent to participants who ordered the test. RESULTS: Of the 7,340 participants in the self-sampling group, 1,196 (16.3%) administered the test, and 1,192 (99.7%) answered the questionnaire. Acceptability of the test was favorable; 75.3-81.3% of participants agreed with positive impressions (easy, convenient, and clarity of instruction), and 65.1-77.8% disagreed with negative impressions (painful, uncomfortable, and embarrassing). However, only 21.2% were confident in their sampling procedure. Willingness to undergo screening with a self-collected sample was significantly higher than that with a doctor-collected sample (89.3% vs. 49.1%; p<0.001). Willingness to undergo screening with a doctor-collected sample was inversely associated with age and duration without screening (both p<0.001), but that with a self-collected sample was not associated. CONCLUSIONS: Among women who used the self-sampling HPV test, high acceptability was confirmed, while concerns about self-sampling procedures remained. Screening with a self-collected sample was preferred over a doctor-collected sample and the former might alleviate disparities in screening rates.

Changes in colorectal cancer treatment during the COVID-19 pandemic in Japan: Interrupted time-series analysis using the National Database of Japan.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic forced us to accept changes in our usual diagnostic procedures and treatments for colorectal cancer. This study aimed to determine the impact of the pandemic on colorectal cancer treatment in Japan. METHODS: The number of colorectal surgeries, stoma constructions, stent placements or long tube insertions, and neoadjuvant chemoradiotherapies were determined each month using sampling datasets from the National Database of Health Insurance Claims and Specific Health Checkups of Japan. The observation periods before and during the pandemic were January 2015 to January 2020 and April 2020 to January 2021, respectively. An interrupted time-series analysis was used to estimate the changes in the number of procedures during the pandemic. RESULTS: The number of endoscopic surgeries for colon cancer significantly decreased in April and July 2020 and for rectal cancer in April 2020. Additionally, the number of laparoscopic and open surgeries for colon cancer significantly decreased in July 2020 and October 2020, respectively. The number of stoma constructions and stent placements or long tube insertions did not increase during the observation period. Neoadjuvant chemoradiotherapy for rectal cancer significantly increased in April 2020 but levels returned shortly thereafter. These results suggest that the recommendations to overcome the pandemic proposed by expert committees, including the replacement of laparoscopic surgery with open surgery, stoma construction to avoid anastomotic leak, and replacement of surgery on the ileus with stent placement, were not widely implemented in Japan. However, as an exception, neoadjuvant chemoradiotherapy for rectal cancer was performed as an alternative treatment to delay surgery in small quantities. CONCLUSION: A declining number of surgeries raises concerns about cancer stage progression; however, we found no evidence to suggest cancer progression from the trajectory of the number of stoma constructions and stent placements. In Japan, even during the pandemic, conventional treatments were performed.

Impact of coronavirus disease 2019 pandemic on breast cancer surgery using the National Database of Japan.

Various countries have reported a decrease in breast cancer surgeries during the coronavirus disease 2019 (COVID-19) pandemic; however, inconsistent results have been reported in Japan. This study revealed changes in the number of surgeries during the pandemic using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) from January 2015 to January 2021, where insurance claims data from Japan as a whole are comprehensively accumulated. The number of breast-conserving surgeries (BCS) without axillary lymph node dissection (ALND) significantly decreased in July (- 846; 95% confidence interval (CI) - 1190 to - 502) and October 2020 (- 540; 95% CI - 861 to - 218). No decrease was observed for other types of surgery, BCS with ALND, and mastectomy with or without ALND. In the age-specific subgroup analysis, significant and transient reduction in BCS without ALND was observed in all age groups (0-49, 50-69, and ≥ 70 years). The number of BCS without ALND significantly decreased for a relatively short period in the early pandemic stages, suggesting reduced surgery for patients with a relatively low stage of cancer. Some patients with breast cancer might have been left untreated during the pandemic, and an unfavorable prognosis would be a concern.

Changes in the number of cancer diagnosis practices due to the COVID-19 pandemic: interrupted time-series analysis using the National Database of Japan.

PURPOSE: This study aimed to reveal the impact of coronavirus disease 2019 on the number of practices commonly used for cancer diagnosis in Japan. METHODS: The sampling dataset of the National Database of Japan from January 2015 to January 2021 was used to generate 25-point time-series data for the number of practices (21 points before and 4 points during the pandemic outbreak). The decreased number was estimated by interrupted time-series analysis using a seasonal autoregressive integrated moving average model. Using the pre-pandemic data, expected counterfactual numbers during the pandemic were predicted, and decreased rate was calculated. RESULTS: In most practices, the number dramatically decreased in the early stage of the pandemic and recovered rapidly thereafter. As of April 2020, gastric endoscopy decreased at the top of the practices (- 42.1%, with 95% confidence intervals of - 50.5% and - 33.7%), followed by gastric biopsy (- 38.6%, with 95% confidence intervals of - 46.7% and - 30.6%). The period of declined practices for lung cancer was relatively prolonged. The number of sentinel lymph node biopsies for breast cancer and colposcopies and biopsies for cervical cancer did not decrease in April 2020, but significantly decreased later in July 2020, which is assumed to be the time lapse after the primary testing before surgical treatment or intense scrutiny. CONCLUSION: In general, the number of practices for cancer diagnosis in Japan showed only a temporary decline, which was concordant with reports from several other countries.

Implementation of a self-sampling HPV test for non-responders to cervical cancer screening in Japan: secondary analysis of the ACCESS trial.

A self-sampling human papillomavirus (HPV) test could improve the morbidity and mortality of cervical cancer in Japan. However, its effectiveness and feasibility have not been demonstrated sufficiently. Hence, we launched a randomized controlled trial, which is ongoing, and report the results of a secondary analysis. To ensure autonomous participation with a minimum selection bias, opt-out consent was obtained from women who met the inclusion criteria, and written consent was obtained from those who underwent a self-sampling test. The number of women who met the inclusion criteria was 20,555; 4283 and 1138 opted out before and after the assignment, respectively. Of the 7340 women in the self-sampling arm, 1372 (18.7%) ordered and 1196 (16.3%) underwent the test. Younger women in their 30 s and 40 s tended to undertake the test more frequently than older women in their 50 s (P for trend < 0.001). Invalid HPV test results were rare (1.3%), and neither adverse events nor serious complaints were reported. Despite adopting the opt-out procedure, more women than expected declined to participate, suggesting the need for a waiver of consent or assignment before consent to reduce selection bias. A self-sampling HPV test can be implemented in Japan and would be more accessible to young women, the predominant group affected by cervical cancer.

Cost-effectiveness of managing HBV reactivation in patients with resolved HBV infection treated with anti-CD20 antibody for B-cell non-Hodgkin lymphoma.

There is no universal recommendation for managing the reactivation of HBV in patients with resolved HBV infection treated with anti-CD20 monoclonal antibodies for B-cell non-Hodgkin lymphoma. This study compared the cost-effectiveness of two commonly used strategies: prophylactic anti-HBV nucleos(t)ide analog therapy (Pro NAT), and HBV DNA monitoring followed by on-demand antiviral therapy (HBV DNA monitoring). Using a decision tree model, the incremental cost-effectiveness ratio (ICER) expressed as cost per quality-adjusted life-year (QALY) gained was calculated. The threshold for cost-effectiveness was set at 5,000,000 JPY, equivalent to 45,662 USD. In a base-case analysis, HBV DNA monitoring was found to be more cost-effective based on the calculation of ICER as 132,048 USD per QALY, a value that far exceeds 45,662 USD. The same results were consistently obtained by a one-way deterministic sensitivity analysis, even after changing each parameter value within the predetermined range. A probabilistic sensitivity analysis with 10,000 simulations also revealed that HBV DNA monitoring is more cost-effective than Pro NAT in 96.8% of cases. Therefore, this study suggests that HBV DNA monitoring is an appropriate managing measure in Japan from a cost-effectiveness perspective.

Study protocol of the ACCESS trial: a randomised trial to evaluate the effectiveness of human papillomavirus testing by self-sampling in cervical cancer screening uptake and precancer detection.

INTRODUCTION: Recently, the incidence of cervical cancer has increased in Japan, probably because of an interruption in human papillomavirus (HPV) vaccination and a low cervical cancer screening rate. There is a lack of evidence for self-sampling HPV testing as a cervical cancer screening tool in Japan. The Accelerating Cervical Cancer Elimination by Self-Sampling test trial aims to compare the effectiveness of screening using the self-sampling HPV test with that of routine screening concerning screening uptake and precancer detection. METHODS AND ANALYSIS: This trial has a single-municipality, open-label, parallel, superiority and randomised design. Approximately 20 000 women who have not undergone cervical cancer screening for at least 3 years will be assigned randomly to the self-sampling arm and the control arm using a 1:1 ratio. Participants assigned to the control arm will undergo routine cervical cancer screening (cytology test) provided by Ichihara City, while those assigned to the self-sampling arm will choose the routine screening or self-sampling HPV test. HPV tests will be performed using the cobas 8800 system (Roche Diagnostics, Rotkreuz, Switzerland). Participants who will undergo the self-sampling HPV testing will be recommended to undergo routine screening. The results of the cytology test and further tests, such as colposcopy and biopsy, will be collected and used for this trial. The risk ratio and risk difference in the proportion of participants with cervical intraepithelial neoplasia two or worse between the two arms will be calculated. The test for the null hypothesis (the detection rates are equal between the two arms) will be performed using Pearson's χ2 test. ETHICS AND DISSEMINATION: This trial was approved by the Research Ethics Committees of the Chiba Foundation for Health Promotion and Disease Prevention and the collaborating research institutes. The results will be disseminated through peer-reviewed journals and conference presentations. TRIAL REGISTRATION NUMBER: jRCT1030200276. Pre-results.

Additional outreach effort of providing an opportunity to obtain a kit for fecal immunochemical test during the general health check-up to improve colorectal cancer screening rate in Japan: A longitudinal study.

OBJECTIVES: A sufficient screening rate is indispensable to optimize the positive impact of colorectal cancer (CRC) screening. This study aimed to evaluate the effect of an additional outreach of providing an opportunity to obtain a kit for fecal immunochemical test (FIT) during the general health check-up to increase CRC screening rate. METHODS: This was a longitudinal study using pre-existing data in Kujukuri Town, Japan. The town provided CRC screening in the fiscal year (FY) 2017 using an existing procedure for all beneficiaries of the National Health Insurance, whereas in FY 2018, an additional outreach effort was made to only those with an even number of age (exposed group), who were offered an opportunity to obtain a kit for FIT at the time of general health check-ups but not to those with an odd number of age (control group). To estimate the effectiveness, generalized estimating equation (GEE) with individuals as clusters was performed. RESULTS: In total, 3,530 individuals were included (1,708 in the control group and 1,822 in the exposed group). GEE showed significant interaction between the groups (control and exposed) and FYs (2017 and 2018) (p<0.001), indicating that the change in CRC screening rate from 2017 to 2018 was significantly different between the two groups. Although an achieved actual rate of 17.1% in the exposed group in FY 2018 was low, the additional outreach increased the rate by 5.8 percentage point (95% confidence interval, 3.5-8.1) compared with an existing rate. CONCLUSIONS: Additional outreach of providing an opportunity to obtain a kit for FIT at the time of the general health check-up improved the CRC screening rate. However, screening rate achieved by this strategy remained low, indicating further efforts is required.

Early induction and increased risk of precursor B-cell neoplasms after exposure of infant or young-adult mice to ionizing radiation.

Epidemiological studies of atomic-bomb survivors have revealed an increased risk of lymphoid neoplasm (i.e. acute lymphoblastic leukemia) associated with radiation exposure. In particular, children are more susceptible to radiation-induced precursor lymphoid neoplasm than adults. Although ~75% of human lymphoid tumors are B-cell neoplasms, the carcinogenic risk associated with each stage of differentiation of B-cells after radiation exposure is poorly understood. Therefore, we irradiated mice at infancy or in young adulthood to investigate the effect of age at exposure on the risk of developing B-cell neoplasms. Histopathology was used to confirm the presence of lymphoid neoplasms, and the population of B-cell neoplasms was classified into the precursor B-cell (pro-B and pre-B cell) type and mature B-cell type, according to immunophenotype. The data revealed that precursor B-cell neoplasms were induced soon after radiation exposure in infancy or young adulthood, resulting in a greater risk of developing the neoplasms. This was particularly the case for the pro-B cell type after young adult exposure. Our findings suggest that exposure to radiation at young age increases the risk of developing precursor B-cell neoplasms in humans.

Handheld flow meter improves COPD detectability regardless of using a conventional questionnaire: A split-sample validation study.

BACKGROUND AND OBJECTIVE: Improved detectability of chronic obstructive pulmonary disease (COPD) using a handheld flow meter (HFM) with symptom-based questionnaires has not been sufficiently evaluated. This study aimed to identify the benefit of using an HFM in COPD screening. METHODS: A total of 2008 participants, who were ≥ 40 years of age, from Isumi City, Japan, were recruited. We developed two novel point systems for detecting COPD, one incorporated score of HFM alone (sHFM) and the other incorporated the score of International Primary Care Airway Group questionnaire (IPAG) and HFM (sIPAG + HFM). Validation using random sample allocation (split-sample validation) was carried out to assess the predictive performance of these models. RESULTS: Participants were assigned to a data set for model creation (n = 1007) or a data set for model assessment (n = 1001) to perform split-sample validation. Decision curve analysis showed that the net benefits of sHFM and sIPAG + HFM were higher than that of the IPAG score (sIPAG) and specificity of the former two were also significantly higher than that of sIPAG. However, the curves of sHFM and sIPAG + HFM were crossing and practically the same with no significant difference in sensitivity and specificity. CONCLUSION: This study confirms that HFM is significantly advantageous in detecting COPD despite the use of a conventional questionnaire.

Inequality within a community at the neighborhood level and the incidence of mood disorders in Japan: a multilevel analysis.

PURPOSE: This study analyzes whether income inequality within a community at the neighborhood level is associated with incidence of mood disorder in Japan. METHODS: A retrospective cohort study was performed using the data of 116,658 National Health Insurance beneficiaries aged between 20 and 69 in Chiba City, Japan. To evaluate income inequality within a community, the Gini coefficient within a 30-min walking distance from an individual's residence was calculated using income distribution estimated by the National Census and the Housing and Land Survey 2013. Incidence of mood disorder was determined through insurance claims submitted from April 1, 2013, to March 31, 2016. A multilevel logistic analysis with three levels-the individual, household, and residential district-was performed to evaluate the association. RESULTS: Income inequality within a community at the neighborhood level was not associated with incidence of mood disorder in the models with and without equivalent household income (p for trend = 0.856 and 0.947, respectively). No difference was observed in the impact of the Gini coefficient among income levels, lower versus higher income groups (p for interaction between Gini coefficient and household income = 0.967). In contrast, lower equivalent income at the household level was significantly associated with higher incidence of mood disorder (p for trend < 0.001). CONCLUSIONS: While we confirmed that lower income at the household level itself had an adverse effect on mental health, income inequality within a community at the neighborhood level was not a significant factor for incidence of mood disorder in Japan.

Chronological changes in epidemiological characteristics of lower urinary tract urolithiasis in Japan.

OBJECTIVES: To determine changes and trends in the annual incidence and epidemiological aspects of lower urinary tract stones in Japan. METHODS: Data about patients who had been diagnosed by urologists in 2015 with first and recurrent lower urinary tract stones were collected from 301 hospitals approved by the Japanese Board of Urology. The estimated annual incidence according to sex, age and stone composition was compared with previous nationwide surveys between 1965 and 2005. RESULTS: The incidence of lower urinary tract stones in Japan has steadily increased from 4.7 per 100 000 in 1965 to 12.0 per 100 000 in 2015. However, the age standardized annual incidence of lower urinary tract stones has remained relatively stable over the same period at 5.5 per 100 000 and 6.0 per 100 000 in 1965 and 2015, respectively. The increase in incidence was most evident among individuals aged ≥80 years. The incidence of calcium oxalate stones has steadily increased among males and females, whereas that of infection-related stones has significantly decreased from 26.2% to 14.3% among men over the past 50 years. CONCLUSIONS: Nationwide surveys suggest a steady increase in the incidence of lower urinary tract stones over a 50-year period in Japan. This trend might reflect changes in the aging population and improved Japanese medical standards.

Medical costs attributable to overweight and obesity in Japanese individuals.

OBJECTIVE: We aimed to reveal the association between body mass index (BMI) and medical costs in the current Japanese population, and to estimate the population attributable fraction (PAF) of medical costs due to overweight and obesity. METHODS: A generalized linear mixed model with log link function and gamma distribution was used to evaluate the association between BMI and medical costs in 34,537 beneficiaries of the National Health Insurance aged 40-69 years in Chiba City. Medical cost data were obtained from insurance claims submitted between April 2012 and March 2016. PAFs due to overweight (BMI ≥25.0 and <30.0kg/m2) and obesity (BMI ≥30.0kg/m2) were calculated. RESULTS: Overweight and obesity were significant predictors of excessive medical costs in all age and sex groups. PAF due to overweight and obesity was estimated to be 9.62% (95% confidence interval, 8.52-10.73%). Additionally, PAFs in 40-59-year-old individuals (12.76% in men and 11.63% in women) were greater than those in 60-69-year-old subjects (6.55% in men and 7.80% in women) for both sexes. CONCLUSIONS: In the Japanese population, overweight and obesity are an excessive financial burden with an estimated PAF of 9.62% of total medical costs.

Chronological changes in the epidemiological characteristics of upper urinary tract urolithiasis in Japan.

OBJECTIVES: To assess epidemiological and chronological trends of upper urinary tract stones in Japan in 2015. METHODS: Patients with a first episode of upper urinary tract stones in 2015 were enrolled in this nationwide survey. The study included all hospitals approved by the Japanese Board of Urology, therefore covering most of the hospitals where urologists practice in Japan. The annual incidence and composition of urolithiasis were evaluated by age and sex. These results were compared with the previous results of the nationwide surveys from 1965 to 2005 to analyze temporal trends. RESULTS: The estimated annual incidence of a first-episode upper urinary tract stone in 2015 was 137.9 (191.9 in men and 86.9 in women) per 100 000. The estimated age-standardized first-episode upper urinary tract stone incidence in 2015 was 107.8 (150.6 in men and 63.3 in women) per 100 000, which did not represent a significant increase since 2005. An equivalent incidence was observed in patients aged >50 years, whereas a reduced incidence was observed in patients aged <50 years in both sexes. The proportion of patients who received percutaneous nephrolithotomy and/or ureteroscopy increased by approximately fivefold in the past 10 years. CONCLUSIONS: The steady increase in the annual incidence of upper urinary tract stones since 1955 leveled off in 2015. The current results show novel trends in the incidence and treatment modalities in the nationwide surveys of urolithiasis in Japan.

Impact of geographic accessibility on utilization of the annual health check-ups by income level in Japan: A multilevel analysis.

Although both geographic accessibility and socioeconomic status have been indicated as being important factors for the utilization of health care services, their combined effect has not been evaluated. The aim of this study was to reveal whether an income-dependent difference in the impact of geographic accessibility on the utilization of government-led annual health check-ups exists. Existing data collected and provided by Chiba City Hall were employed and analyzed as a retrospective cohort study. The subjects were 166,966 beneficiaries of National Health Insurance in Chiba City, Japan, aged 40 to 74 years. Of all subjects, 54,748 (32.8%) had an annual health check-up in fiscal year 2012. As an optimal index of geographic accessibility has not been established, five measures were calculated: travel time to the nearest health care facility, density of health care facilities (number facilities within a 30-min walking distance from the district of residence), and three indices based on the two-step floating catchment area method. Three-level logistic regression modeling with random intercepts for household and district of residence was performed. Of the five measures, density of health care facilities was the most compatible according to Akaike's information criterion. Both low density and low income were associated with decreased utilization of the health check-ups. Furthermore, a linear relationship was observed between the density of facilities and utilization of the health check-ups in all income groups and its slope was significantly steeper among subjects with an equivalent income of 0.00 yen than among those with equivalent income of 1.01-2.00 million yen (p = 0.028) or 2.01 million yen or more (p = 0.040). This result indicated that subjects with lower incomes were more susceptible to the effects of geographic accessibility than were those with higher incomes. Thus, better geographic accessibility could increase the health check-up utilization and also decrease the income-related disparity of utilization.

Income-Related Inequalities in Access to Dental Care Services in Japan.

Background: This study aimed to evaluate whether income-related inequalities in access to dental care services exist in Japan. Methods: The subjects included beneficiaries of the National Health Insurance (NHI) in Chiba City, Japan, who had been enrolled from 1 April 2014 to 31 March 2015. The presence or absence of dental visits and number of days spent on dental care services during the year were calculated using insurance claims submitted. Equivalent household income was calculated using individual income data from 1 January to 31 December 2013, declared for taxation. Results: Of the 216,211 enrolled subjects, 50.3% had dental care during the year. Among those with dental visits, the average number of days (standard deviation) spent on dental care services per year was 7.7 (7.1). Low income was associated with a decreased rate of dental care utilization regardless of age and sex. However, there was a significant inverse linear association between the number of days spent on dental care services and income levels for both sexes. Conclusions: There were income-related inequalities in access to dental care services, regardless of the age group or sex, within the Japanese universal health insurance system.

Survey of motivation to participate in a birth cohort.

For a longitudinal prospective cohort study to be successful, participants' motivation to provide information must be maintained. Therefore, this study aimed to identify items that effectively promote participants' motivation. Questionnaires were mailed to 4541 mothers and expectant mothers in Chiba Prefecture, Japan who participated in a nationwide birth cohort. A total of 2387 (52.6%) responses were received. The following items were identified as primary motivating factors among our cohort: "benefits to the participants' children", "monetary compensation" and "contribution to a better future environment". More than 30% of the respondents expressed a lack of understanding regarding the study purpose and requirements for participation. About 14% were concerned about the leakage of personal information, and 13% felt burdened by having to make a long-term commitment to the study. Cluster analysis identified four groups, two of which, one with extremely low levels of motivation and the other motivated by only money or goods, lacked an understanding of the study and tended to be concerned about the associated risks and burdens. Participants in these groups were considered to be at a high risk of dropout. Therefore, implementing measures to provide participants with a better understanding of cohort studies could lead to more successful results.