Decisions and Influential Factors Regarding Class-Specific School Closures Against Seasonal Influenza Outbreak.

Background One of the characteristics of school closure in Japan is class-specific school closure, which involves a reactive, short-term closure in the event of an infectious disease outbreak. These closures are implemented at each school in reaction to the annual seasonal influenza outbreaks. Very little research has addressed the formation of class-specific school closures to combat infectious diseases in elementary schools. We carried out a survey on factors involved in the decision to close classes and the determination of the timing and duration of class closures in elementary schools in Japan. Methods A mail-based questionnaire survey of elementary schools from four prefectures in western Japan was conducted between August and September 2021. The questions addressed the criteria for school closures (the timing and duration of class closure), various considerations, and confusion regarding class closures, with answers analyzed using descriptive statistical methods. Results In total, 714 elementary schools responded to the survey (37.9%). Furthermore, 398 (55.7%) schools established criteria for class closures during seasonal influenza. Class closure was most frequently initiated in schools with criteria when either 20% or 30% of class pupils were absent; the most common duration was three days. The duration of class closures was decided upon depending on the outbreak in some schools (69.8%), depending on the circumstances of the outbreak. Regarding class closure decisions, schools viewed school physicians' opinions as a priority, followed by school events, adjustments for Saturdays and Sundays, and Yogo teachers' opinions. Schools answering "no criteria for class closure" or "adjustments for Saturdays and Sundays" had difficulty determining class closure duration. Conclusion To guarantee the continuation of children's education and improve the effectiveness of preventive efforts against seasonal influenza, the following were considered important and helpful in class closure decision-making in elementary schools: scientific evidence, the school physician's opinion, and Yogo teachers' analysis of children's health information.

Breast Cancer Screening and Perceptions of Harm among Young Adults in Japan: Results of a Cross-Sectional Online Survey.

Breast cancer is the most commonly diagnosed female cancer and the leading cause of cancer death. Early detection and treatment are important to reduce the number of deaths. Japan recommends mammography every two years for women over 40 years of age. However, in recent years, an increasing number of younger women have been undergoing breast cancer screening (BCS). To reduce the harms of BCS among young adults, our study extracted data from an online survey conducted in 2018 and applied χ2 tests and logistic analysis to identify the influencing factors regarding interest in undergoing BCS. The results of our analysis support the need for a reduction in the BCS rate through awareness regarding the harms of health screening among young people. In particular, for those who receive BCS through occupational screening, we believe that improving education on breast awareness, the accuracy of occupational screening, and breast self-examination methods could reduce the harms from BCS in younger age groups.

Factors Affecting the Cervical Cancer Screening Behaviors of Japanese Women in Their 20s and 30s Using a Health Belief Model: A Cross-Sectional Study.

In recent years, the incidence and mortality rates of cervical cancer (CC) have increased among young women. Cervical cancer screening (CCS) is crucial to reducing the incidence and mortality of CC in a country such as Japan, where it is challenging to raise HPV vaccination rates. The purpose of this study was to identify psychological and personal characteristics relating to CCS participation among young people by using the Health Belief Model (HBM). For this cross-sectional study, an internet survey was conducted between February-March 2018. Based on HBM and personal characteristics, χ2 tests and logistic analyses were used to identify factors influencing CCS. Responses obtained from 816 women in their 20s and 30s were used in the analysis. For HBM-based psychological characteristics, the odds ratios were significantly higher for "cues to participation in screening" and "barriers to participation at the time of cancer screening", while "barriers to participation before cancer screening" showed significantly lower odds ratios. On the other hand, it was found that the presence of children and having regular health checkups affected the attributes of screening that were significant for decision-making. Therefore, it is important to create proactive measures to encourage younger women to undergo medical examinations.

Feasibility and acceptability of telepathology system among the rural communities of Bangladesh: A pilot study.

Context: Telepathology is a promising tool for remote communities to receive pathology services where professional diagnosis services are inadequate. Aims: We aimed to clarify how effective telepathology was when compared with conventional pathology service among rural communities of Bangladesh. Methods and Materials: We conducted a cross-sectional study in suburban and rural areas of Bangladesh between June and August 2020. We enrolled 117 participants who received both telepathology services from Thakurgaon Eye Hospital and conventional pathology service experience. The participant's satisfaction with the accessibility and perceptions were statistically compared. In addition, we summarized descriptive statistics using the frequencies and percentages of participants' responses. Statistical Analysis Used: Wilcoxon's Signed-rank test using SPSS statistic software version 25.00. Results: Among the study participants, service cost, travel cost, travel time, waiting time, and travel distance were significantly higher for conventional pathology than telepathology (P < 0.001). The majority of participants (94%) were satisfied with the telepathology experience; however, one out of 117 participants was dissatisfied with this service when their travel distance was far away (≥50 km). Among the participants, 91.5% thought that telepathology service was effective for their treatment, and 98.3% wanted to continue this service in their community. On an average, participants saved 58% (95% CI, 53.4-61.5) of cost using telepathology rather than conventional pathology service. Conclusions: Remote under-resourced communities received professional pathology services with less time-consuming and significantly lower costs using the telepathology approach. Where pathology services are absent/insufficient, telepathology is efficacious for primary diagnosis, screening, and referral through professional pathologists for the satisfactory treatment of unreached communities.

Physical Functions and Comorbidity Affecting Collapse at 4 or More Weeks after Admission in Patients with Osteoporotic Vertebral Fractures: A Prospective Cohort Study.

STUDY DESIGN: A prospective cohort study. PURPOSE: This study aimed to reveal physical functions and comorbidity affecting collapse at ≥4 weeks after hospital admission of patients with osteoporotic vertebral fracture. OVERVIEW OF LITERATURE: Only a few studies have investigated the influence of physical function and activity on collapse in patients with osteoporotic vertebral fractures. METHODS: This prospective cohort study analyzed patients with osteoporotic vertebral fractures admitted to the hospital between March 2018 and October 2019. Logistic regression analysis was performed to explore the predictors of vertebral collapse at >4 weeks after admission. Model 1 used basic medical information and physical functions at admission; model 2 used basic medical information and physical function and activity at >4 weeks after admission. RESULTS: In the model 1 results of logistic regression analysis, cardiovascular disease (odds ratio [OR], 12.27; 95% confidence interval [CI], 1.28-117.91) was extracted as a factor affecting vertebral collapse at ≥4 weeks after admission. In the model 2 results of logistic regression analysis, cardiovascular disease (OR, 34.57; 95% CI, 2.53-471.74), movement control during one leg standing at 4 weeks (OR, 7.25; 95% CI, 1.36-38.71), and Pain Catastrophizing Scale score at 4 weeks (OR, 1.11; 95% CI, 1.01-1.21) were extracted as factors affecting vertebral collapse at ≥4 weeks after admission. CONCLUSIONS: Our results indicate that physical functions and comorbidity affect collapse at ≥4 weeks after admission in patients with osteoporotic vertebral fractures.

Factors of Having Difficulties Raising 3-Year-Old Children in Japan: Usefulness of Maternal and Child Health Information Accumulated by the Local Government.

Background: Difficulties raising children may be associated with depressive tendencies and abuse by parents, for which maternal and child health information may be useful. We clarified factors related to difficulties in raising children at the time of the 3-year-old child health checkup. Method: This was a retrospective cohort study. We used maternal and child health information collected from the time of pregnancy notification until the 3-year-old child health checkup. The subjects were the parents of 507 children who were born and eligible for the 3-year-old child health checkup between September 2013 and October 2017. Logistic regression and ROC analyses were performed. The dependent variable was "having difficulties raising children at the 3-year-old health checkup". Result: Eleven factors were clarified as risk factors. Three major factors among them were having difficulties raising children at the 18-month-old checkup (adOR, 6.3; 95%CI, 3.0-13.9), actions are at the child's own pace and adult instructions are difficult to follow at the 18-month-old health checkup (adOR, 5.0; 95%CI, 1.3-25.4), and EPDS score ≥ 2 (adOR, 3.4; 95%CI, 1.5-8.1). The AUC of this predictive model was 0.86. At a cutoff value of 0.387, the sensitivity was 79.7% and the specificity was 77.6%. Conclusion: Having difficulties raising children at the 3-year-old health checkup has factors from the time of pregnancy and requires continued support. It was possible and useful to use maternal and child health information when screening high-risk parents.

Health Literacy, Health Behaviors, and Body Mass Index Impacts on Quality of Life: Cross-Sectional Study of University Students in Surabaya, Indonesia.

University student life is an important transformation stage with many potential factors that can impact negatively on the Quality of Life (QOL) and the adoption of unhealthy behaviors. Health literacy (HL), Health Behaviors (HBs), and Body Mass Index (BMI) have been found to be essential components in influencing QOL, in addition to socioeconomic determinants. To identify the influential factors of QOL, we performed a cross-sectional survey in a university, and 955 undergraduate students were enrolled as respondents. We measured two different aspects of HL, i.e., Comprehensive Health Literacy (CHL) and Functional Health Literacy (FHL). Overall, QOL scores in four domains did not differ, regarded as medium with averages ranging from 57.00-63.98, and no significant difference between male and female students. In multivariate analysis, CHL had a significant positive influence on all domains, while FHL only affected the psychological and environmental domains with negative associations. Academic performance had a significant positive association with physical and psychological domains. Students from education majors had higher QOL in the psychological and social domains. Moreover, students with normal or underweight BMI status had better psychological QOL, and physical exercise had a positive association with the social relationship and environmental domains. The findings confirmed that CHL and FHL had significant associations with QOL domains in different ways that should be addressed accordingly. Public health practitioners should carefully empower students to use both CHL and FHL as decision-making skills by incorporating them into related curricula.

Quantifying the Effects of Medical Examination and Possible Risk Factors against the Incidence of Cervical Cancer in a Low Human Papillomavirus Vaccination Coverage: An Ecological Study in Japan.

Cervical cancer (CC) is one of the most common gynecological malignancies in females, mainly caused by human papillomavirus (HPV). In countries with lower HPV vaccine coverage, such as Japan, medical examination may play a key role in decreasing CC incidence. This study aimed to quantify the effect of medical examination on cervical cancer (CC) incidence in Japan, considering the effects of possible risk factors. By collecting Japan's Prefectural data on CC incidence (2013-2017), incidence of sexually transmitted diseases (STDs; Chlamydia, Herpes, Condyloma, and Gonorrhea; 1993-2012), screening and detailed examination rate against CC (2013-2016), smoking rate (2001-2013), economic status (disposable income and economic surplus; 2014-2015), and education status (2015), we analyzed associations among them using Pearson's correlation coefficients. Additionally, assuming that the incidence of STDs reflects the frequency of risky sexual behavior at the co-infection point with HPV, we constructed generalized linear models to predict CC incidence, taking a 5-20-year time-lag between incidences of STDs and the CC incidence. Against CC incidence, Chlamydia in females and Gonorrhea in males with a 15-year time-lag showed positive associations, while Condyloma in both genders with a 15-year time-lag, screening rate, economic status, and smoking rate showed negative associations. An increase in screening test rate by 10% was estimated to decrease CC incidence by 9.6%. This means that screening tests decrease CC incidence effectively, but not drastically, suggesting the need for additional countermeasures for CC prevention.

Health Literacy and Health Behavior: Associated Factors in Surabaya High School Students, Indonesia.

(1) Background: The health behavior (HB) of adolescents develops in the school or family setting and plays an important role in their future health status. Health literacy (HL) has been identified as an important factor in modifying health behavior in addition to socioeconomic factors. health-promoting school (HPS) programs also have a significant role in providing students with the means of learning the importance of knowledge, behavior, and skills for a healthy lifestyle. (2) Method: This study aims to identify the association between HB, HL measured in comprehensive health literacy (CHL) and functional health literacy (FHL), HPS programs, and socioeconomic factors among high school students in Surabaya, Indonesia. A cross-sectional study was conducted, and 1066 students were evaluated as respondents. (3) Result: The results of multivariate analyses showed that following factors were associated with better health behavior: female, better academic performance, higher grade, higher father's education, lower allowance, and better CHL and FHL. The strongest association for HB was gender. CHL was especially associated with handwashing, physical activity, and drug abuse. FHL was associated with smoking and drug abuse. The implementation of HPS programs did not reach an optimum level and only influenced physical activity. (4) Conclusions: The findings confirm that CHL and FHL have a significant association with several HBs. HB intervention in the HPS program is recommended to incorporate the CHL and FHL for a better health impact.

Factors Affecting Quality of Life at Discharge among Patients with Osteoporotic Vertebral Fractures.

OBJECTIVES: This study aimed to identify factors, including physical functions and activities that affect quality of life (QOL) at discharge among patients with osteoporotic vertebral fractures. METHODS: Patients with osteoporotic vertebral fractures were included in our prospective cohort study. Multiple regression analysis was performed to determine the predictors of QOL at discharge using two models: model 1, basic medical information and physical functions at admission, and model 2, basic medical information, physical function, and activity after 4 weeks of admission. RESULTS: Multiple regression analysis (standard partial regression coefficients) using model 1 identified L2 to L4 bone mineral density (-0.2), Visual Analog Scale for pain during activity at admission (-0.31), and Revised Hasegawa Dementia Scale (HDS-R) score at admission (0.64) as factors affecting QOL at discharge. Multiple regression analysis using model 2 identified HDS-R at admission (0.64), Pain Catastrophizing Scale score at 4 weeks (-0.34), and knee extension muscle strength at 4 weeks (0.28) as factors affecting QOL at discharge. CONCLUSIONS: Our results suggest that if patients have high bone mineral density, intense pain, and low cognitive function at admission, then low QOL at discharge will be predicted; however, improvement of pain catastrophizing and knee extension muscle strength during first the 4 weeks of admission may be able to improve QOL at discharge. Because patients in this study were Japanese only, it is important to exercise caution when applying our results to other populations.

Analysis of the Training Effect of a Nursing Undergraduate Course on the Management of Radiation-Related Health Concerns-A Single Group Experiment.

After the 2011 Fukushima Daiichi accident, demands regarding nursing staff's management of nuclear disasters have increased. This study aimed to evaluate a basic training program to teach undergraduate nursing students on how to deal with public anxiety following a nuclear disaster. We analyzed the data of 111 third-year nursing students attending a Japanese university. We set attainment goals in three domains (cognitive, affective, psychomotor) regarding their acquisition of consultation techniques for radiation-related health concerns. We compared pre- and post-class response scores on a knowledge test and calculated word frequencies in health consultation scenarios. The pre-class mean score was 12.2 out of 27 points and the post-class mean score (directly after the course) was 21.0, a significant increase (p < 0.001). The mean level of attainment in each of the three domains increased significantly from pre-test to post-test (p < 0.001). The variety and number of words in the health consultations also increased. Students attained the program goals for radiation-related health concerns in all domains. During disasters, there is a great need for nursing staff to administer physical and mental care to the public. This program was evaluated to be one wherein nursing staff can acquire fundamental knowledge about radiation in a short time.

Interactive effect of cognitive function and intervention on the walking independence of stroke patients: a retrospective cohort study.

The purpose of this study was to investigate the interactive effect of cognitive function and intervention on walking independence of stroke patients. Stroke patients (n=405) who admitted to convalescent rehabilitation ward, were classified as being walking independent or dependent. To examine the interaction between cognitive function and intervention, high cognitive function (functional independence measure score ≥20) and physical therapy and occupational therapy intervention delivered in 1 day (lasting >2 hr) were defined as cognition-intervention interaction and included as independent variables. The incidence of walking independence was calculated using Kaplan-Meier curves. Intergroup differences were estimated using log-rank test. Cox proportional hazards analysis was used to extract the predictors of walking independence. Survival analyses using Kaplan-Meier log-rank test showed that the probability of incidence of walking independence was significantly higher in the presence of a cognition-intervention interaction. The results of Cox proportional hazards analysis showed that age, left versus right cerebral damage, and cognition-intervention interaction significantly influenced walking independence at discharge from the hospital. The hazard ratios were 0.971 per year of age, 0.544 for left versus right cerebral damage, and 1.794 for cognition-intervention interaction. Walking independence was more likely to be achieved by stroke patients with high cognitive function who received therapy. In other words, the conditions that increase the likelihood of an effect of therapy intervention on walking independence were identified in this study.

Predicting Healthy Lifestyle Behaviours Among Patients With Type 2 Diabetes in Rural Bali, Indonesia.

BACKGROUND: Type 2 diabetes is a lifelong metabolic disease closely related to unhealthy lifestyle behaviours. This study aimed to identify factors explaining the healthy lifestyle behaviours of patients with type 2 diabetes in rural Indonesia. The extended health belief model, demographic characteristics, clinical lifestyle factors and diabetes knowledge were investigated to provide a complete description of these behaviours. METHOD: A sample of 203 patients with type 2 diabetes representing a cross-section of the population were recruited from community health centres in the rural areas of Bali province. The data were collected through questionnaires. Descriptive statistics and a hierarchical regression test were employed. RESULTS: This study showed demographic characteristics, clinical and lifestyle factors, diabetes knowledge and the extended health belief model accounted for 71.8% of the variance in healthy lifestyle behaviours of patients with type 2 diabetes in rural Indonesia. The significant demographic factors were age, education level, employment status and traditional beliefs. The significant clinical and lifestyle factors were alcohol use, diabetic medicine and duration of symptoms. Finally, the significant extended health belief model factors were perceived severity, susceptibility, barriers, family support, bonding social capital and chance locus of control. CONCLUSIONS: The extended health belief model forms an adequate model for predicting healthy lifestyle behaviours among patients with diabetes in rural Indonesia. The contribution of this model should be strengthened in developing the diabetes management.

Factors affecting hospital readmission heart failure patients in Japan: a multicenter retrospective cohort study.

The purpose of this study was to examine factors influencing readmission to hospital in patients with heart failure. This multicenter, retrospective cohort study analyzed 197 heart failure patients admitted to the research cooperation facilities between January 2017 and November 2017. We defined the readmission group as being readmitted to hospital in ≤ 6 months of discharge and the non-readmission group as > 6 months after discharge. Cox proportional hazards analysis was performed to explore the predictors of readmission. The incidence of readmission was calculated using Kaplan-Meier curves for the extracted factors. Intergroup differences were estimated using the log-rank test. The results of Cox proportional hazards analysis indicated that chronic renal dysfunction (hazard ratio (HR) = 4.729), dementia (HR = 7.105), HFrEF (HR = 8.138), walking without support (HR = 4.031), and walking with a cane (HR = 11.857) significantly contributed to the model. In the survival analyses using the Kaplan-Meier log-rank test, chronic renal dysfunction, dementia, and HFrEF were significant (P < 0.05), but walking without support and walking with a cane after discharge were not significant (P > 0.05). This study suggests that early involvement after discharge is important for lowering the readmission rates in patients with heart failure, even when their walking ability is good.

Warm Front Passage on the Previous Day Increased Ischemic Stroke Events.

BACKGROUND AND PURPOSE: The influence of a weather front passage is rarely evaluated on stroke events. We hypothesized that a weather front passage on the stroke onset day or during the previous days may play an important role in the incidence of stroke. METHODS: A multicenter retrospective study was conducted to evaluate the frequency of stroke events and their interaction with weather front passages. Consecutive acute stroke patients (n = 3935, 73.5 ± 12.4 years, 1610 females) who were admitted to 7 stroke hospitals in 3 cities from January 2012 to December 2013 were enrolled in this study. Multivariate Poisson regression models involving time lag variables were used to compare the daily rates of stroke events with the day of a weather front passage and the previous 6 days, adjusting for considerable influences of ambient temperature and atmospheric pressure. RESULTS: There were a total of 33 cold fronts and 13 warm fronts that passed over the 3 cities during the study period. The frequency of ischemic stroke significantly increased when a warm front passed on the previous day (risk ratio 1.34, 95% confidence interval 1.07-1.69, P= .016). CONCLUSIONS: This study indicated that a weather front passage on the previous days may be associated with the occurrence of stroke.

Can the Amount of Interventions during the Convalescent Phase Predict the Achievement of Independence in Activities of Daily Living in Patients with Stroke? A Retrospective Cohort Study.

BACKGROUND: This study aimed to evaluate the diagnostic performance of the amount of physical, occupational, and speech therapy intervention and optimal timing necessary for activities of daily living (ADL) independence in patients with stroke. METHOD: Patients (N = 441) with stroke admitted to the convalescent rehabilitation ward were classified into an early intervention or a nonearly intervention group on the basis of the duration from the date of onset to date of hospital admission. Logistic regression model was used to identify factors influencing independence in ADL in both groups. Cutoff point, likelihood ratio, and posterior probabilities for ADL independence were calculated, and diagnostic accuracy was evaluated for extracted factors. RESULTS: Results of logistic regression analysis revealed that age and physical and occupational therapy intervention amount provided during convalescent phase and Functional Independent Measure (FIM) motor score at admission significantly influenced independence in ADL at discharge from the hospital in the early intervention group (hospitalization date was 30 days or less). The cutoff point was 168 hours; positive likelihood ratio was 1.74; negative likelihood ratio was .78; and the posterior probability for the time spent by the therapist was 81.0%. FIM motor score at admission was the only factor extracted for the nonearly intervention group (hospitalization date was 31 days or more). CONCLUSION: The ADL independence in patients with stroke admitted to convalescent rehabilitation ward during their convalescent phase cannot be determined simply on the basis of the amount of physical and occupational therapy they receive.

Various meteorological conditions exhibit both immediate and delayed influences on the risk of stroke events: The HEWS-stroke study.

We hypothesized that meteorological conditions on the onset day and conditions on the former days may play important roles in the modulation of physical conditions. Associations of meteorological factors and their changes in former days with stroke onset are of interest. We conducted a multicenter retrospective study to evaluate the frequency of stroke events and their interaction with meteorological conditions and their daily changes. Acute stroke patients (n = 3935, 73.5±12.4 years, 1610 females) who were admitted to 7 stroke hospitals in three restricted areas were enrolled in this study. Poisson regression models involving time-lag variables was used to compare daily rates of stroke events with mean thermo-hydrological index (THI), atmospheric pressure, and their daily changes. We divided onset days into quintiles based on the THI, atmospheric pressure, and their daily changes for the last 7 days. The frequencies of ischemic stroke significantly increased when THI varied either cooler or warmer from a previous day (extremely cooler, risk ratio (RR) 1.19, 95% confidence interval (CI) 1.05 to 1.34; extremely warmer, RR 1.16, 95% CI 1.03 to 1.31; r2 = 0.001 for the best regression, p = 0.001). Intracerebral hemorrhage frequencies significantly decreased on high-THI days (extremely high, RR 0.72, 95% CI 0.54 to 0.95; r2 = 0.013 for the best regression, p<0.001) and increased in high atmospheric pressure days (high, RR 1.31, 95% CI 1.04 to 1.65; r2 = 0.009 for the best regression, p<0.001). Additionally, even after adjusting for the THI on the onset day and its changes for the other days, intracerebral hemorrhage increased when THI got extremely cooler in 4 days prior (RR 1.33, 95% CI 1.03 to 1.71, r2 = 0.006 for the best regression, p<0.001). Various meteorological conditions may exhibit influences on stroke onset. And, when temperature cooled, there may be a possibility to show delayed influence on the frequency of intracerebral hemorrhage 4 days later.

Effects of Meteorological Conditions on the Risk of Ischemic Stroke Events in Patients Treated with Alteplase--HEWS-tPA.

BACKGROUND: Predicting a day that presents a high risk for the occurrence of ischemic stroke events may enable health professionals to prepare for emergency stroke therapy more properly. We evaluated the association between meteorological conditions and the frequency of ischemic stroke events in Japanese patients. METHODS: Ischemic stroke patients (n = 299) who were treated with alteplase at 9 stroke hospitals in 3 restricted areas were examined. The daily rates of ischemic stroke events were compared with the daily mean thermo-hydrological index (THI), the atmospheric pressure, and the daily changes of these variables for the 6 days preceding an ischemic stroke event using Poisson regression analysis. RESULTS: We trisected onset days based on the THI (low-temperature, intermediate-temperature, and high-temperature), atmospheric pressure (low-pressure, intermediate-pressure, and high-pressure), changes in THI for preceding 6 days from the previous day (cooler, unchanged-temperature, and warmer), and changes in atmospheric pressure (decreased-pressure, unchanged-pressure, and increased-pressure). The frequency of ischemic stroke was significantly higher on low-temperature or high-pressure days (risk ratio, 1.398, P = .022; risk ratio, 1.374, P = .039), on warmer-temperature days, and when atmospheric pressure varied from the day before (P < .05). There were significantly lower risks for ischemic stroke events on cooler-temperature days, and higher risks were associated with a variation in atmospheric pressure 3 days before the onset from 4 days before (P < .05). CONCLUSIONS: There were higher risks for ischemic stroke events associated with low ambient temperature, high atmospheric pressure, increased temperature, and varied atmospheric pressure. Also, atmospheric pressure variation 3 days before may be associated.

An analysis of mass screening strategies using a mathematical model: comparison of breast cancer screening in Japan and the United States.

BACKGROUND: Although the United States Preventive Services Task Force (USPSTF) downgraded their recommendation for breast cancer screening for women aged 40-49 years in 2009, Japanese women in their 40s have been encouraged to attend breast cancer screenings since 2004. The aim of this study is to examine whether these different mass-screening strategies are justifiable by the different situations of these countries and to provide evidence for suitable judgment. METHODS: Performance of screening strategies (annual/biennial intervals; initiating/terminating ages) was evaluated using a mathematical model based on the natural history of breast cancer and the transition between its stages. Benefits (reduced number of deaths and extended average life expectancy) and harm (false-positives) associated with these strategies were calculated. RESULTS: Additional average life expectancy by including women in their 40s as participants were 13 days (26%) and 25 days (22%) in Japan and the United States, respectively, under the biennial screening condition; however, the respective increases in numbers of false-positive cases were 65% and 53% in Japan and the United States. Moreover, the number of screenings needed to detect one diagnosis or to avert one death was smaller when participants were limited to women of age 50 or over than when women in their 40s were included. The validity of including women in their 40s in Japan could not be determined without specifying the weight of harms compared to benefits. CONCLUSIONS: Whether screening of women in their 40s in Japan is justifiable must be carefully determined based the quantitative balance of benefits and harms.