Journal of Epidemiology

Volume 30, Issue 3 (March 2020)

1) Special Article
Japanese Legacy Cohorts: Six-Prefecture Cohort Study (Hirayama Cohort Study)
● Late Dr. Takeshi Hirayama and his collaborators conducted a large-scale cohort study in six prefectures in Japan (Miyagi, Aichi, Osaka, Hyogo, Okayama, Kagoshima), which is called the Six-Prefectures Cohort Study or Hirayama Cohort Study.
● Its baseline survey covered male and female residents aged 40 and over based on the National Census in 1965, of whom 264,118 people (equivalent to 94.8% of the total population) were followed for 17 years until the end of 1982.
● One of the most important findings obtained from Hirayama Cohort Study was the association between second-hand smoke exposure and lung cancer mortality, which triggered the worldwide spread of smoking ban in indoor public places and workplaces.
● This special article presented a succinct summary of the main findings obtained from the study, paying respect to the foresight and the leadership of late Dr. Takeshi Hirayama, and his outstanding contributions to improving national and global public health.

2) Relationship Between Severe Respiratory Depression and Codeine-Containing Antitussives in Children: A Nested Case-Control Study
● Occurrence of respiratory depression was very rare.
● The association of codeine with respiratory depression was insignificant.
● Our findings have important clinical and health policy implications.

3) Elevated Fasting Blood Glucose Levels Are Associated With Lower Cognitive Function, With a Threshold in Non-Diabetic Individuals: A Population-Based Study
● Investigated relationships between cognition and fasting blood glucose.
● Cognitive ability screening instrument (CASI) was used to assess cognition.
● 3.97-6.20mmol/L glucose associated with highest cognition in men without diabetes.
● Higher glucose was associated with lower cognition in men with diabetes.
● Distinct relationships between glucose and cognition by diabetes status were found.

4) Plain Water Intake and Association With the Risk of Overweight in the Chinese Adult Population: China Health and Nutrition Survey 2006–2011
● An inverse dose-response relationship existed between plain water intake and new-onset overweight risk.
● More than 4 cups (≈1 liter) plain water intake per day was associated with the reduction of overweight risk.
● The association of plain water intake and overweight risk was independent of socioeconomic and lifestyle factors.

5) The Association Between Education and Smoking Prevalence, Independent of Occupation: A Nationally Representative Survey in Japan
● Independent of occupation, lower education level was significantly related to current smoking among the Japanese general population.
● Educational disparities in smoking were larger among the younger generation than among older people, especially among women aged 20–39 years.
● Regarding occupation, after adjustment of education and other covariates, significantly higher smoking prevalence in manual workers than in upper non-manual workers was found only in men aged 20–64 years.
● Among women aged 65 or older, manual workers were less likely to be current smokers than upper non-manual workers, while among women aged 20–64 years, occupation was not associated with smoking.
● The current study suggests that we should pay attention to social inequality in smoking as well as national smoking prevalence.

6) Socio-Economic Disparities in Early Childhood Education Enrollment: Japanese Population-Based Study
● Although studies from other developed countries have shown that the benefits of center-based childcare may be most pronounced among socioeconomically disadvantaged families, such families are less likely to use it.
● Socio-economic disadvantage (e.g., low income and mother’s low education) were associated with the non-use of center-based childcare.
● Child’s health and developmental problems (e.g., preterm birth) were also associated with the non-use of center-based childcare.

Volume 30, Issue 2 (February 2020)

1)Utility of a Specific Health Checkup Database Containing Lifestyle Behaviors and Lifestyle Diseases for Employee Health Insurance in Japan
● Lifestyle and associated diseases were examined by the Specific Health Checkup (SHC).
● Results were compared with data from the National Health and Nutrition Survey.
● SHC subjects were younger, had better lifestyle behaviors.
● SHC subjects had lower prevalence of metabolic syndrome, diabetes and hypertension.
● Developing health policies would benefit from selection of an appropriate database.

2) Self-Reported Hearing/Visual Loss and Mortality in Middle-Aged and Older Adults: Findings From the Komo-Ise Cohort, Japan
● Hearing loss and dual sensory loss might be risk factors of mortality over ten years.
● Hearing loss was primarily associated with cancer mortality.
● Depression, walking disability, and social participation modestly mediated the association.

3) Sociodemographic Factors Influenced Response to the 2015 National Nutrition Survey on Preschool Children: Results From Linkage With the Comprehensive Survey of Living Conditions
● Overall response rate to the 2015 National Nutrition Survey on Preschool Children (NNSPC) was 64.1%.
● Response rates varied according to sociodemographic factors such as residential area, family structure, economic status, and maternal characteristics.
● Some bias, mostly small, was seen in survey estimates of the 2015 NNSPC.

4) Dental Status is Associated With Incident Functional Disability in Community-Dwelling Older Japanese: A Prospective Cohort Study Using Propensity Score Matching
● 13-year prospective cohort study in 574 elderly Japanese to determine the relationship between dental status and functional disability.
● Reduction of confounding factors in the study population with propensity score matching.
● Participants with 0-19 teeth have a higher risk to develop functional disability than those with 20 or more teeth.

5) Incidence and Age Distribution of Hospitalized Presumptive and Possible Abusive Head Trauma of Children Under 12 Months Old in Japan
● Capturing incidence of abusive head trauma (AHT) is important for evaluating intervention effectiveness.
● No studies reported the incidence of AHT in Japan.
● This study revealed similar incidence of possible AHT to other countries.
● The month-age distribution uniquely showed two peaks for around 2 and 8 months old.
● Further research is needed to prevent AHT among children in early and late infancy.

6) Dietary Inflammatory Index Positively Associated With High-Sensitivity C-Reactive Protein Level in Japanese From NIPPON DATA2010
● The significant associations were observed between DII scores and CRP in almost all age-sex Japanese groups.
● The DII is applicable to the Japanese population.
● DII score cannot be used to compare the inflammatory potential of diets of different countries directly without using the same food parameters.

Volume 30, Issue 1 (January 2020)

1)Decline in Handgrip Strength From Midlife to Late-Life is Associated With Dementia in a Japanese Community: The Hisayama Study
● Greater decline in handgrip strength over 15 years from midlife to late-life was associated with higher risks of total dementia and Alzheimer's disease.
● Maintaining muscle strength into late-life is important for preventing dementia.

2) Trends in Serum Lipid Levels of a 10- and 13-Year-Old Population in Fukuroi City, Japan (2007–2017)
● We investigated trends in serum lipids from 2007 to 2017 in a population of 10- and 13-year-old children in Fukuroi City, Japan.
● No remarkable changes in the prevalence of adverse LDL-C and HDL-C levels were observed regardless age or sex, while the prevalence of high non-HDL-C increased in boys.
● Serum LDL-C and HDL-C levels slightly increased in boys and girls aged 10 years, and HDL-C levels slightly increased in girls aged 13 years.

3) Serum Pepsinogen Values in Japanese Junior High School Students With Reference to Helicobacter Pylori Infection
● Accurate infection diagnosis was pursued with both serum and urine tests.
● In the analyses, 171 H. pylori non-infected and 8 infected students were included.
● Infected students showed higher pepsinogen I and II and lower I to II ratio.
● The distributions of serum pepsinogen differed clearly from that in adults.
● In non-infected students, males showed higher pepsinogen values than females.

4) Association of Vegetable, Fruit, and Okinawan Vegetable Consumption With Incident Stroke and Coronary Heart Disease
● We aimed to elucidate associations of total Okinawan vegetable consumption as well as total fruit and vegetable consumption with risk of incident stroke and coronary heart disease among participants who lived in Okinawa Prefecture.
● Total and specific Okinawan vegetable consumption were not statistically significantly associated with risk of stroke and coronary heart disease.
● Consumption of total vegetable and fruit in Japanese residents of Okinawa was also not associated with risk of incident stroke and coronary heart disease.

5) Study Profile
The Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT): Study Design and Participants
● Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT) was launched in 2011 to identify risk factors for lifestyle-related disease, elucidate factors which extend healthy life expectancy, and contribute toward personalized healthcare.
● Between 2011 and 2016, a baseline survey was conducted at 16 municipalities in 7 prefectures across the country.
● We have established a population-based cohort of 115,385 persons (Response rate 44.1%), among whom 55,278 (47.9% of participants) have provided blood and urine samples.