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There have been few studies on cancer incidence and survival among children in Japan. Childhood cancer cases in Hiroshima City can be ascertained almost perfectly in terms of completeness and validity as both a population-based cancer registry and a tissue registry cover the whole area. We report here recent incidence and survival of childhood cancer in Hiroshima City. Subjects were cancer patients less than 15 years of age in Hiroshima City registered in the Hiroshima City Cancer Registry and/or the Hiroshima Prefecture Tumor Registry (tissue registry) between 1998 and 2000. Cancer incidence in Hiroshima City was calculated for 12 diagnostic groups according to the International Classification of Childhood Cancer, and compared with general incidence in Japan. Five-year survival was calculated by the Kaplan-Meier method. There were 63 children who had a cancer newly diagnosed during 1998-2000, with only one death-certificate-only case (1.6%). Age-standardized incidence rates (per million) were 144.3 for boys and 93.9 for girls. Leukemia was the most frequent (29%) among the 12 diagnostic groups. There were 13 cancer deaths during this period and five-year survival was 79% (95% Confidence Interval: 67%-87%). Childhood cancer incidence was slightly higher than that for all of Japan, but the relative distribution of patients by diagnostic group was compatible with the general pattern. Both of these observations might be due to the high quality of the tumor and tissue registries.

In Japan, a decrease in cardiovascular mortality has coincided with reduced population salt intake since the 1950s. The purpose of this study was to quantify the effect of reduced population salt intake on the long-term trends of cardiovascular mortality. Using government statistics and epidemiological study results in people of 20–69 years old from 1950 to 2017, including the National Health and Nutrition Survey, we developed a system dynamics model of age-specific cardiovascular mortality and salt intake. We estimated the period and cohort effects on mortality and calibrated the model for the historical mortality rate. We then simulated the counterfactual scenario of no decrease in salt intake to estimate the reduction in cardiovascular deaths associated with decreased mean salt intake. Compared with the base run and calibrated to the actual data, approximately 298,000 and 118,000 excess deaths were observed in men and women, respectively, assuming no change in salt intake over the entire period. The model suggests that the decline in salt intake since the 1950s has contributed to a non-negligible reduction in cardiovascular mortality. [ABSTRACT FROM AUTHOR]

Reducing population dietary salt intake is expected to help prevent cardiovascular disease and thus constrain increasing national healthcare expenditures in Japan's super-aged society. We aimed to estimate the impact of achieving global and national salt-reduction targets (8, <6, and <5 grams/day) on cardiovascular events and national healthcare spending in Japan. Using published data including mean salt intake and systolic blood pressure from the 2019 National Health and Nutrition Survey, we developed a Markov model of a closed cohort of adults aged 40–79 years in 2019 (n = 66,955,000) transitioning among six health states based on the disease course of ischemic heart disease (IHD) and stroke. If mean salt intake were to remain at 2019 levels over 10 years, cumulative incident cases in the cohort would be approximately 2.0 million for IHD and 2.6 million for stroke, costing USD 61.6 billion for IHD and USD 104.6 billion for stroke. Compared with the status quo, reducing mean salt intake towards the targets over 10 years would avert 1–3% of IHD and stroke events and save up to 2% of related national healthcare costs. Attaining dietary salt-reduction goals among adults would yield moderate health economic benefits in Japan. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to examine the relationships between education and mortality and incidence for major sites of cancer in a Japanese population. Methods: Subjects were 32,883 respondents of questionnaire survey in 1978 with ages younger than 75 years. Cancer cases were ascertained through 2001, and causes of deaths were identified through 2003. Hazard ratios of deaths from cancer or developing cancers were compared among those with 9 or less, 10–12, and 13 years or more of education using Cox proportional hazard models. Results: As for cancer mortality of all sites combined, a statistically significantly decreasing trend was observed in age-adjusted models in both men and women, but no significant differences were observed in multivariate-adjusted (age, body mass index, smoking, radiation dose, and city) models. Among major cancer sites (stomach, colon/rectum, liver, lung, and female breast) examined, a significantly decreasing trend was observed for male liver cancer in a multivariate-adjusted model. As for incidence, a significantly decreasing trend was observed for cancer of all sites combined in men, and for male liver and prostate cancer and female lung cancer in a multivariate-adjusted model. Conclusions: Educational differences in cancer incidence and mortality were generally rather small, but were significant for incidence for male all-site, male liver, prostate, and female lung cancers. [Copyright &y& Elsevier]

Abstract: In Japan, cohort studies on stroke have been mainly conducted in rural areas, with few studies comparing stroke mortality between urban and rural areas. We aimed to explore urban–rural difference in stroke mortality throughout Japan using a representative sample of the general Japanese population, the NIPPON DATA80. This study included 9309 subjects (4080 men and 5229 women) aged 30 years or older who were residents of 294 areas in 211 municipalities of Japan in 1980 and followed-up until 1999. Population size of the municipality in which the aforementioned areas were located was used to distinguish between urban and rural areas, because municipalities in Japan are classified as village, town or city principally by population size. We applied a multilevel logistic regression model to take into account the hierarchical data structure of individuals (subjects) (level 1) nested within areas (level 2), and then calculated odds ratios and 95% confidence intervals (CIs) of deaths from total stroke. Statistically significant variance between areas was not observed in men but was in women. Age-adjusted odds ratios of the areas in the medium (population⩾30,000 and <300,000) and small municipalities (<30,000) compared with the areas in the large municipalities (⩾300,000) were 1.31 and 1.40 in men, and 1.32 and 1.62 in women, respectively. Multivariate-adjusted odds ratios (adjusted for age, body mass index, total cholesterol, diabetes, hypertension, current smoking, and daily alcohol consumption) of the areas in the medium and small municipalities compared with the areas in the large municipalities were 1.29 and 1.36 in men, and 1.34 and 1.68 in women, respectively. In conclusion, stroke mortality tended to be higher in rural areas than in urban areas in Japan, especially among women. [Copyright &y& Elsevier]

We aimed to quantify contributions of changes in risks and uptake of evidence-based treatment to coronary heart disease (CHD) mortality trends in Japan between 1980 and 2012. We conducted a modelling study for the general population of Japan aged 35 to 84 years using the validated IMPACT model incorporating data sources like Vital Statistics. The main outcome was difference in the number of observed and expected CHD deaths in 2012. From 1980 to 2012, age-adjusted CHD mortality rates in Japan fell by 61%, resulting in 75,700 fewer CHD deaths in 2012 than if the age and sex-specific mortality rates had remained unchanged. Approximately 56% (95% uncertainty interval [UI]: 54–59%) of the CHD mortality decrease, corresponding to 42,300 (40,900–44,700) fewer CHD deaths, was attributable to medical and surgical treatments. Approximately 35% (28–41%) of the mortality fall corresponding to 26,300 (21,200–31,000) fewer CHD deaths, was attributable to risk factor changes in the population, 24% (20–29%) corresponding to 18,400 (15,100–21,900) fewer and 11% (8–14%) corresponding to 8400 (60,500–10,600) fewer from decreased systolic blood pressure (8.87 mm Hg) and smoking prevalence (14.0%). However, increased levels of cholesterol (0.28 mmol/L), body mass index (BMI) (0.68 kg/m2), and diabetes prevalence (1.6%) attenuated the decrease in mortality by 2% (1–3%), 3% (2–3%), and 4% (1–6%), respectively. Japan should continue their control policies for blood pressure and tobacco, and build a strategy to control BMI, diabetes, and cholesterol levels to prevent further CHD deaths. What is already known this topic • Age-adjusted mortality of coronary heart disease (CHD) has declined since 1980 in many developed countries. • This mortality fall in Japan occurred in spite of recent increases in obesity, cholesterol, and Westernized dietary changes. What this study adds • In Japan, the declining in CHD deaths was explained by smoking, systolic blood pressure (BP), and treatment for CHD. • These successes have been slightly offset by adverse increases in diabetes (DM), body mass index (BMI), and cholesterol. • Japan should keep control policies for BP and tobacco, make plans for DM, BMI, and dyslipidemia to prevent future CHD deaths. [ABSTRACT FROM AUTHOR]

Abstract.: To determine the possible late health effects of atomic-bomb radiation, Radiation Effects Research Foundation (RERF) has been conducting mortality follow-up on a fixed cohort of 120,000 members (Life Span Study cohort or LSS cohort) since 1950. Through record linkage with local cancer registries in Hiroshima and Nagasaki, RERF has also been conducting cancer incidence studies of atomic bomb survivors since 1958. The central finding of the study is an increase in cancer risk. Besides the increase in leukemia risk, increase in risks of solid cancers such as cancers of the breast, lung and colon have also been demonstrated. Radiation-induced leukemia occurred 2 to 3 years after exposure, reached its peak within 6 to 8 years after the bombing, and has since declined steadily. However, radiation-related solid cancer began to appear at later years and the risk still remains to be present, even today. An increase of solid cancer risk appears to be larger for those exposed as children than those exposed as adults. However, since a majority of those exposed as children are still alive and risk estimates for them are uncertain at this stage, it is essential to continue their follow-up. Recently, the LSS also demonstrates an excess risk of death from non-cancer diseases, largely from cardiovascular, digestive and respiratory diseases. Further investigation is of absolute necessity in order to determine whether or not the excess was caused by atomic bomb radiation. [Copyright &y& Elsevier]