In preparation for a collaborative multidisciplinary study of the pathogenesis of esophageal cancer, the authors reviewed the published literature to identify similarities and differences between Japan and China in esophageal cancer epidemiology. Esophageal squamous cell carcinoma (ESCC) is the predominant histologic type, while the incidence of esophageal adenocarcinoma remains extremely low in both countries. Numerous epidemiologic studies in both countries show that alcohol consumption and cigarette smoking are contributing risk factors for ESCC. There are differences, however, in many aspects of esophageal cancer between Japan and China, including cancer burden, patterns of incidence and mortality, sex ratio of mortality, risk factor profiles, and genetic variants. Overall incidence and mortality rates are higher in China than in Japan, and variation in mortality and incidence patterns is greater in China than in Japan. During the study period (1987–2000), the decline in age-adjusted mortality rates was more apparent in China than in Japan. Risk factor profiles differed between high- and low-incidence areas within China, but not in Japan. The association of smoking and drinking with ESCC risk appears to be weaker in China than in Japan. Genome-wide association studies in China showed that variants in several chromosome regions conferred increased risk, but only genetic variants in alcohol-metabolizing genes were significantly associated with ESCC risk in Japan. A well-designed multidisciplinary epidemiologic study is needed to examine the role of diet and eating habits in ESCC risk.

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In Japan, the prevalences of type 2 diabetes and depression are increasing, but evidence linking these diseases to diet is limited. The present study reviewed the association of type 2 diabetes with intakes of rice, fish/seafood, and soy product and isoflavone, and the association of depressive symptoms with folate, vitamin D, and dietary pattern, in the Japanese population. The analysis of type 2 diabetes comprised around 55 000 men and women aged 45 to 75 years who completed a questionnaire for the Japan Public Health Center-based Prospective Study and were free of type 2 diabetes at baseline. The odds ratio of self-reported physician-diagnosed type 2 diabetes during the subsequent 5 years increased with rice intake among women and among physically inactive men but decreased with total fish/seafood intake among men. In addition, risk tended to decrease with soy product and isoflavone intake among overweight and postmenopausal women. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. The participants were approximately 530 workers aged 21 to 67 years who participated in a health survey at the time of a periodic health check. A cross-sectional and prospective inverse association between serum folate and depressive symptoms was observed. Serum 25-hydroxyvitamin D level was suggestively associated with decreased prevalence of depressive symptoms in late autumn. In addition, a healthy Japanese pattern—characterized by high intakes of vegetables, fruit, mushrooms, and soy products—was inversely associated with depressive symptoms. The findings suggest that diet has a role in the development of type 2 diabetes and depression in Japanese.

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Background: We used the results of a contact behavior survey in conjunction with droplet pattern measurement to investigate the indoor population transmission dynamics of respiratory infections.
Methods: A total of 404 questionnaires on all contact behaviors were distributed to junior high school students. Droplet number concentration and size distribution generated by coughing and talking were measured by droplet experimentation. A deterministic susceptible–exposed–infected–recovery (SEIR) model was used to simulate the indoor transmission dynamics of influenza infection among schoolchildren.
Results: Results indicated that the average contact rates ranged from 9.44 to 11.18 person⁻¹ day⁻¹ for grades 7 to 9. We showed that total median droplet number concentrations were 9.01 × 10⁷ and 8.23 × 10⁷ droplets per cubic meter for coughing and talking, respectively. Population dynamic simulations indicated that the size-dependent median number of droplets per person resulted in a maximum of 8 and 10 infected persons on day 4, respectively, for talking and coughing activities.
Conclusions: Human contact behavior and airborne droplet characteristics may substantially change predicted indoor population transmission dynamics of influenza infection.

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Background: Evidence is lacking on whether health guidance for metabolic syndrome reduces health care expenditures. The author used propensity-score matching to evaluate the effects of health guidance on health care expenditure.
Methods: Men who did and did not receive health guidance from a health insurance society (approximately 60 000 covered lives) were matched (n = 397 respectively) using propensity scores. Health insurance claims were compared using cumulative health care expenditures for metabolic syndrome-related outpatient medical care and drug costs for the period from the initial consultation to 3 years later.
Results: No difference was observed between intervention and control groups in cumulative outpatient charges or drug costs related to metabolic syndrome. However, regression analysis using the Tobit model showed that health guidance resulted in a small, nonsignificant reduction in health care expenditure.
Conclusions: Health guidance for metabolic syndrome did not reduce outpatient charges or drug costs related to metabolic syndrome during the 3-year period after the intervention. Findings from Tobit regression suggest that health guidance might eventually result in savings, but this hypothesis remains untested.

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Background: We evaluated the recent prevalence of serologic markers of hepatitis A virus (HAV) in South Korea.
Methods: The study data were the results of 60 126 anti-HAV (total) tests and 30 786 anti-HAV IgM tests that were performed during April 2009 through March 2010 by the Eone Reference Laboratory at the request of 1935 institutions throughout Korea.
Results: The overall positivity rate was 51.06% on the anti-HAV (total) test and 11.20% on the anti-HAV IgM test. As compared with the other age groups the rate of anti-HAV (total) positivity was significantly lower (P < 0.001), and the rate of anti-HAV IgM positivity was significantly higher (P < 0.001), among Koreans aged 11 to 40 years. The seroprevalence of anti-HAV IgM significantly differed according to region but not by referral date.
Conclusions: This was the largest nationwide study in South Korea by 1 laboratory, and it provides useful recent baseline data on hepatitis A in Asia. The findings suggest that active immunization of younger Koreans should be made a priority.

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Background: Determining standard pubertal growth patterns using longitudinal anthropometric measures is important in growth assessment. We used an appropriate repeated-measurements method to identify height growth patterns in Japanese school-aged girls and boys.
Methods: The participants were children born during the period from 1991 through 1999 who had entered the first grade of elementary school in the Enzan district in Koshu City, Japan. This study was part of the Project Koshu cohort study. Height was measured annually in April from the first grade of elementary school (age, 6–7 years) to the third grade of junior middle school (age, 14–15 years). Height gain and growth rate trajectories in boys and girls were constructed using multilevel analysis.
Results: In total, 1984 children (1036 boys and 948 girls) were included in this study. Height in boys and girls was similar at age 6.5 to 9.5 years. Girls subsequently grew faster and were taller than boys at age 10.5 to 11.5 years. Starting at age 12.5 years, male height caught up and exceeded female height. Height gain trajectories showed that annual height gain among girls increased slowly and peaked during age 9.5 to 11.5 years, while male height gains declined slightly at first and peaked at age 11.5 to 12.5 years. Sex differences in height gains were significant during the period from age 7.5 to 14.5 years (P < 0.0001). Growth rate and height gain trajectories were similar between sexes.
Conclusions: Sex differences in growth trajectory were significant, and female height gain peaked approximately 2 years earlier than male height gain.

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Background: Concentrations of ambient air pollution and pollutants in China have changed considerably during the last decade. However, few studies have evaluated the effects of current ambient air pollution on the health of kindergarten children.
Methods: We studied 6730 Chinese children (age, 3–7 years) from 50 kindergartens in 7 cities of Northeast China in 2009. Parents or guardians completed questionnaires that asked about the children’s histories of respiratory symptoms and risk factors. Three-year concentrations of particles with an aerodynamic diameter ≤10 µm (PM₁₀), sulfur dioxide (SO₂), and nitrogen dioxides (NO₂) were calculated at monitoring stations in 25 study districts. A 2-stage regression approach was used in data analyses.
Results: The prevalence of respiratory symptoms was higher among children living near a busy road, those living near chimneys or a factory, those having a coal-burning device, those living with smokers, and those living in a home that had been recently renovated. Among girls, PM₁₀ was associated with persistent cough (odds ratio [OR]_PM10 = 1.44; 95% CI, 1.18–1.77), persistent phlegm (OR_PM10 = 1.36; 95% CI, 1.02–1.81), and wheezing (OR_PM10 = 1.31; 95% CI, 1.04–1.65). NO₂ concentration was associated with increased prevalence of allergic rhinitis (OR = 1.96; 95% CI, 1.27–3.02) among girls. In contrast, associations of respiratory symptoms with concentrations of PM₁₀, SO₂, and NO₂ were not statistically significant among boys.
Conclusions: Air pollution is particularly important in the development of respiratory morbidity among children. Girls may be more susceptible than boys to air pollution.

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Background: We estimated the prevalence and incidence of chronic intestinal pseudo-obstruction (CIPO) in Japan, investigated the patterns of hospital visits among those with CIPO, and examined present knowledge of CIPO among medical professionals.
Methods: A self-administered questionnaire survey was distributed to targeted hospitals throughout Japan, which were selected using stratified random sampling. The questionnaire asked about the number of patients receiving treatment for CIPO, the frequency of their hospital visits, and overall clinical knowledge of CIPO among medical professionals.
Results: CIPO prevalence was estimated to be 1.00 and 0.80 cases per 100 000 males and females, respectively. Incidence was 0.21 and 0.24 cases per 100 000 males and females, respectively. Prevalence and incidence did not significantly differ males and females. Mean age of patients was 63.1 years for males and 59.2 for females. Accurate diagnosis of CIPO sometimes required more than 3 months after initial presentation. Most medical professionals were unaware of or poorly understood CIPO.
Conclusions: We estimated the prevalence and incidence of CIPO in Japan, using data from a nationwide survey. The findings suggest that knowledge of CIPO should be further disseminated so that the disease is not overlooked and is diagnosed without delay.

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Background: Diabetes is an important risk factor for cardiovascular disease, certain types of cancer, and death, and self-reports are one of the most convenient methods for ascertaining diabetes status. We evaluated the validity of diabetes self-reports among Japanese who participated in a health checkup.
Methods: Self-reported diabetes was cross-sectionally compared with confirmed diabetes among 2535 participants aged 28 to 85 years in the Saku cohort study. Confirmed diabetes was defined as the presence of at least 1 of the following: fasting plasma glucose (FPG) level of 126 mg/dL or higher, 2-hour post-load glucose (2-hPG) level of 200 mg/dL or higher after a 75-gram oral glucose tolerance test, glycated hemoglobin (HbA1c) level of 6.5% or higher, or treatment with hypoglycemic medication(s).
Results: Of the 251 participants with self-reported diabetes, 121 were taking hypoglycemic medication(s) and an additional 69 were classified as having diabetes. Of the 2284 participants who did not self-report diabetes, 80 were classified as having diabetes. These data yielded a sensitivity of 70.4%, a specificity of 97.3%, a positive predictive value of 75.7%, and a negative predictive value of 96.5%. The frequency of participants with undiagnosed diabetes was 3.0%. Of these, 64.2% had FPG within the normal range and were diagnosed by 2-hPG and/or HbA1c.
Conclusions: Our findings provide additional support for the use of self-reported diabetes as a measure of diabetes in epidemiologic studies performed in similar settings in Japan if biomarker-based diagnosis is difficult.

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Background: Using data from a large-scale community-based Japanese population, we attempted to identify factors associated with tooth loss in middle-aged and elderly men.
Methods: A total of 8352 men aged 40 to 79 years who lived in the north of the main island of Japan and underwent health checkups were enrolled between 2002 and 2005. Number of teeth was assessed by the question, “How many teeth do you have (0, 1–9, 10–19, or ≥20)?”. On the basis of the answer to this question, participants were classified into 2 groups (≤19 teeth or ≥20 teeth). Using multivariate logistic regression, factors related to having 19 or fewer teeth were estimated.
Results: The numbers (percentages) of participants who had 0, 1 to 9, 10 to 19, and 20 or more teeth were 1764 (21.1%), 1779 (21.3%), 1836 (22.0%), and 2973 (35.6%), respectively. Among the participants overall and those aged 65 to 79 years, having 19 or fewer teeth was significantly associated with older age, smoking status (current smoking and ex-smoking), and low education level. In addition, men with 19 or fewer teeth were more likely to have a low body mass index and low serum albumin level and less likely to be current alcohol drinkers. Among men aged 40 to 64 years, but not men aged 65 to 79 years, those with 19 or fewer teeth were more likely to have a low serum high-density lipoprotein cholesterol level and high glycosylated hemoglobin (HbA1c) level.
Conclusions: Smoking, low education level, and poor nutritional status were associated with tooth loss among middle-aged and elderly Japanese men.

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Background: In February 2009, a high school student was diagnosed with sputum-smear positive pulmonary tuberculosis (TB). One year later, 2 other students in the same grade developed sputum-smear positive TB.
Methods: We used tuberculin skin testing (TST), chest radiography, sputum smear, and symptomatology for case identification. We defined latent TB infection (LTBI) as a TST induration of 15 mm or larger, probable TB as a chest radiograph indicative of TB plus productive cough/hemoptysis for at least 2 weeks or TST induration of 15 mm or larger, and confirmed TB as 2 or more positive sputum smears or 1 positive sputum smear plus a chest radiograph indicative of TB.
Results: Of students in the same grade as the primary case-student, 26% (122/476) had LTBI and 4.8% (23/476) had probable/confirmed TB. Of teachers, 43% (18/42) had LTBI and none had probable/confirmed TB. Sharing a classroom with the primary case-student increased risk for LTBI (rate ratio = 2.5; 95% CI: 1.9–3.4) and probable/confirmed TB (rate ratio = 17, 95% CI: 7.8–39). Of students with LTBI in February 2009 who refused prophylaxis, 50% (11/22) had probable/confirmed TB in April 2010.
Conclusions: This TB outbreak was likely started by delayed diagnosis of TB in the case-student and was facilitated by lack of post-exposure chemoprophylaxis. Post-exposure prophylaxis is strongly recommended for all TST-positive students.

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