The social implementation of knowledge and technologies that are effective in epidemiological and observational studies is essential for solving social issues. In particular, there have been few attempts to implement clinical practices and information communication technologies that utilize data in the field. We describe the four stages of social implementation: 1) redefining social issues as solvable problems, 2) finding technological solutions to solvable problems, 3) social implementation contributing to the solutions, and 4) horizontal deployment of effective methods for solving social issues. Introducing a use case of artificial intelligence (AI) social implementation in child-abuse response conducted by our team, we discuss pitfalls and tips as a frame of reference to demonstrate data utilization as social infrastructure for solving social issues and to consider practical solutions in a logical manner.

Background: Food allergies are common among children, and food-induced anaphylaxis (FIA) is a serious disease with a risk of death; however, there is yet to be a large-scale epidemiological study on causative foods in Japan. The purpose of this study was to identify foods that cause FIA in Japan.

Methods: We identified 9,079 patients from the Japanese Diagnosis Procedure Combination Database who were admitted for treatment for FIA from April 1, 2014 through March 31, 2017. We extracted data on patient sex, age, use of epinephrine injections on the first day, prescription for epinephrine self-injection on the day of discharge, length of stay, readmission, and causative foods.

Results: The most common causative food was eggs, followed by wheat, milk, peanuts, and buckwheat. The most common causative food in each age group was eggs among 0–3-year-olds, milk among 4–6-year-olds, peanuts among 7–19-year-olds, and wheat among those aged 20 years and older. Epinephrine was used at admission among about 40%, 50%, and over 60% of cases in which the causative food was eggs; wheat, milk and peanuts; and buckwheat, respectively. The proportion of cases with a prescription for epinephrine self-injection at discharge was highest among those in which the causative food was wheat, followed by peanuts, buckwheat, milk, and eggs.

Conclusions: FIA due to peanuts has become as common in Japan as it is in the West. These results suggest the importance of taking measures to prevent peanut allergies because children cannot make adequate decisions regarding food.

Background: Although prevalence of low birth weight has increased in the last 3 decades in Japan, no studies in Japanese women have investigated whether birth weight is associated with the risk of pregnancy complications, such as pregnancy-induced hypertension (PIH) and gestational diabetes mellitus (GDM).

Methods: We used data from the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT), a population-based cohort study in Japan that launched in 2011. In the main analysis, we included 46,365 women who had been pregnant at least once, for whom information on birth weight and events during their pregnancy was obtained using a self-administered questionnaire. Women were divided into five categories according to their birth weight, and the relationship between birth weight and risk of PIH and GDM was examined using multilevel logistic regression analyses with place of residence as a random effect.

Results: Compared to women born with birth weight of 3,000–3,999 grams, the risk of PIH was significantly higher among women born <1,500 grams (adjusted odd ratio [aOR] 1.60; 95% confidence interval [CI], 1.17–2.21), 1,500–2,499 grams (aOR 1.16; 95% CI, 1.03–1.30), and 2,500–2,999 grams (aOR 1.13; 95% CI, 1.04–1.22). The risk of GDM was significantly higher among women born 1,500–2,499 grams (aOR 1.20; 95% CI, 1.02–1.42), albeit non-significant association among women in other birthweight categories.

Conclusions: We observed an increased risk of PIH among women born with lower birth weight albeit non-significant increased risk of GDM among Japanese women.

Background: The number of people providing informal caregiving, including dual care, which is the combination of child and nursing care, is increasing. Due to the burden of multiple responsibility, dual care could negatively affect the health of informal caregivers. Previous research has not studied the effects of combining different types of informal caregiving. Therefore, we examined, among Japanese women, 1) the association between types of informal caregiving and self-rated health (SRH), and 2) difference in this association according to caregivers’ socio-economic conditions.

Methods: We analyzed the nationally representative 2013 Comprehensive Survey of Living Conditions data of 104,171 women aged 20–59 years. The odds ratios (ORs) for poor SRH by type of informal caregiving (no care, childcare, nursing care, and dual care) were estimated using logistic regression. We also conducted sub-group analyses by socio-economic conditions (equivalent monthly household expenditure and educational attainment).

Results: Compared to the no care group, the adjusted ORs for poor SRH of the childcare, nursing-care, and dual care groups were 0.92 (95% confidence interval [CI], 0.88–0.97), 1.33 (95% CI, 1.21–1.47), and 1.42 (95% CI, 1.23–1.64), respectively. There was no extra risk arisen from combining childcare and nursing care. The sub-group analyses indicated that neither household expenditure nor educational attainment affected the association between caregiving type and poor SRH.

Conclusion: Our study found that informal nursing care and dual care impose a health burden on female caregivers, regardless of their socio-economic conditions. This highlights the importance of addressing the effects of informal caregiving on the health of women.

Background: Heated tobacco product (HTP) use in Japan has rapidly increased. Despite this rapid spread, little is known about the health effects of HTP use. We conducted a longitudinal cohort study to investigate the change in smoking habits following the spread of HTP use and its effect on forced expiratory volume in 1 second (FEV₁) decline.

Methods: Participants consisted of a resident population (n = 2,612; mean age, 67.7 years) with FEV₁ measurement in 2012–2014 and 2018–2019, and a worksite population (n = 722; mean age 49.3 years) without FEV₁ data. Participants were categorized as combustible cigarette-only smokers, HTP-only users, dual users, past smokers, and never smokers. The association between smoking group and the change in smoking consumption over a mean 5.6 years was examined. Differences in annual FEV₁ change between smoking groups were examined in the resident population.

Results: Prevalence of HTP-only and dual users in 2018–2019 was 0.8% and 0.6% in the resident population, and 5.0% and 1.9% in the worksite population, respectively. The overall number of tobacco products smoked/used increased in dual users compared to baseline, but not in others. Annual FEV₁ decline in dual users tended to be greater than that in cigarette-only smokers (16; 95% confidence interval, −34 to 2 mL/year after full adjustment). Participants switching to HTP-only use 1.7 years before had a similar FEV₁ decline as cigarette-only smokers.

Conclusions: HTP use, including dual use, is prevalent even in a rural region of Japan. Dual users appear to smoke/use tobacco products more and have a greater FEV₁ decline. Tobacco policy should consider dual use as high-risk.

Background: Reluctance of people to receive recommended vaccines is a growing concern, as distribution of vaccines is considered critical to ending the COVID-19 pandemic. There is little information regarding pregnant women’s views toward coronavirus vaccination in Japan. Therefore, we investigated the vaccination rate and reasons for vaccination and vaccine hesitancy among pregnant women in Japan.

Methods: We conducted a cross-sectional study involving 1,791 pregnant women using data from the Japan “COVID-19 and Society” Internet Survey, conducted from July to August 2021, and valid response from 1,621 respondents were analyzed. We defined participants with vaccine hesitancy as those who identified with the statement “I do not want to be vaccinated” or “I want to ‘wait and see’ before getting vaccinated.” Multivariate Poisson regression analysis was used to investigate the factors contributing to vaccine hesitancy.

Results: The prevalence of vaccination and vaccine hesitancy among pregnant women was 13.4% (n = 217) and 50.9% (n = 825), respectively. The main reasons for hesitancy were concerns about adverse reactions and negative effects on the fetus and breastfeeding. Vaccine hesitancy was significantly associated with the lack of trust in the government (adjusted prevalence ratio, 1.26; 95% confidence interval, 1.03–1.54). Other factors, such as age, educational attainment, and state of emergency declaration, were not associated with vaccine hesitancy.

Conclusions: COVID-19 vaccination is not widespread among pregnant women in Japan, although many vaccines have been shown to be safe in pregnancy. Accurate information dissemination and boosting trust in the government may be important to address vaccine hesitancy among pregnant women.

Background: Coronavirus disease 2019 (COVID-19) has disproportionately affected the most vulnerable populations. We assessed the prevalence and disparities of economic hardships and their impact on health deterioration in Japan.

Methods: Data were obtained from a nation-wide, cross-sectional, internet-based, self-reported survey conducted during August–September, 2020 with individuals aged 15–79 years in Japan (n = 25,482). Economic hardships and changes in various physical and mental health status were measured using sample-weighted data. Adjusted prevalence ratios (APRs) were estimated to investigate the associations between economic hardships and health outcomes.

Results: During April–September, 2020 in Japan, 25.0%, 9.6%, 7.9%, and 3.1% of the respondents experienced income loss, money shortage, financial anxiety and financial exploitation, respectively, with higher prevalence among workers (vs non-workers). Stratifying by sex and working status, income loss was associated with physical health deterioration (APRs ranged from 1.45–1.95), mental health deterioration (APRs ranged from 1.47–1.68), and having serious psychological distress (APRs ranged from 1.41–2.01) across all strata. Shortage of money and financial anxiety were also associated with increased likelihood of all adverse health outcomes assessed, regardless of whether the hardships were pre-existing or experienced first time. Among non-working individuals, financial exploitation was associated with physical health deterioration among males (APR 1.88) and mental health deterioration among both males (APR 1.80) and females (APR 2.23), while such associations were not observed among working individuals.

Conclusions: During the early phase of the COVID-19 epidemic, COVID-19-related economic hardships were associated with physical and mental health deterioration in Japan, particularly among the vulnerable populations. Timely and prompt responses are warranted to mitigate both economic and health burdens.