The differential effects of low income and material deprivation—in particular, deprivation related to child educational needs—have not been well examined. This study aimed to examine the effects of low income and life-related and child-related deprivation on child behavioral problems. This study used data from first-grade students who participated in the Adachi Child Health Impact of Living Difficulty (A-CHILD) study in 2015, 2017, and 2019 (N = 12,367) in Japan. Material deprivation was divided into life-related deprivation (i.e., lack of items for a living) and child-related deprivation (i.e., lack of children’s books, etc.), and low income was assessed via annual household income. We assessed child behavioral problems and prosocial behavior using the Strengths and Difficulties Questionnaire. One in ten children belonged to low-income families, 15.4% of children experienced life-related deprivation, and 5.4% of children experienced child-related deprivation. While life- and child-related deprivation had significant adverse effects on behavioral problems, they had no association with prosocial behavior. The effects of low income were mediated by parental psychological distress (45.0% of the total effect) and the number of consulting sources (20.8%) on behavioral problems. The effects of life-related and child-related deprivation were mediated by parental psychological distress (29.2–35.0%) and the number of consulting sources (6.4–6.9%) on behavioral problems. Life-related and child-related deprivation, but not low income, are important for child mental health.

Dietary intake of adequate quality and quantity in early life is essential for healthy growth and development. This study aimed to examine the association between one-year change in growth and diet quality in preschool children in Adachi City, Tokyo, Japan. A total of 110 participants (49% boys, four to five years old at baseline) were included in this analysis. Body mass index for age z-score (BAZ) and height for age z-score (HAZ) were calculated in accordance with WHO reference. Dietary intakes were assessed using the brief-type self-administered diet history questionnaire for children (BDHQ3y), and daily quality score was calculated based on the Japanese Food Guide Spinning Top (JFGST score). Regression analyses found no significant association between one-year change in growth and diet quality (compared to a low JFGST score, BAZ: β = 0.16, 95% CI: −0.29 to 0.60 for a middle JFGST score, β = −0.14, 95% CI: −0.61 to 0.33 for a high JFGST score, HAZ: β = −0.15, 95% CI: −0.50 to 0.21 for a middle JFGST score, β = −0.06, 95% CI: −0.43 to 0.30 for a high JFGST score). Further studies are needed to develop an appropriate diet quality index for healthy growth in Japanese preschool children.

The aim of this study was to examine the association between toothbrushing frequency and school refusal among elementary school children. We used data from the Adachi Child Health Impact of Living Difficulty (A-CHILD) longitudinal study conducted between 2015 and 2016 in Adachi City, Tokyo, Japan. A questionnaire was distributed to all first-grade children aged 6 to 7 years (N = 3697, follow-up rate: 86.2%). Propensity score (PS) matching was applied to collapse the known covariates on toothbrushing frequency in grade 1 on the association with school refusal in grade 2. Among the followed children, 2.4% showed school refusal in grade 2 (89 children) and 23.5% (870 children) brushed their teeth once or less than once daily in grade 1. After propensity score matching, children with toothbrushing once or less than once daily in grade 1 were 2.25 (95% CI: 1.25–4.05) times more likely to show school refusal in grade 2, compared with those with toothbrushing twice or more a day. Our findings suggest that toothbrushing once or less than once daily is an independent risk factor for school refusal among children. Oral health promotion to recommend toothbrushing more than once a day could prevent school refusal. Further intervention studies investigating the mechanism and causality are warranted.

Fathers' involvement in childcare has been increasing in recent years. However, very little is known about the health impact on fathers when they are caring for or living with a disabled child. This study aims to understand the psychological distress and subjective health outcomes among fathers living with a disabled child compared to fathers living without a disabled child. Data for this study were obtained from the Comprehensive Survey of the Living Conditions conducted by the Ministry of Health, Labour and Welfare in 2016. Multivariable logistic regression was used among 438 disabled-child and father dyads and 27,682 non-disabled-child and father dyads to analyse the association between a child's disability status with father's health outcomes. Fathers of disabled children had a higher prevalence of psychological distress (17% vs. 12%) and poor subjective health status (13% vs. 8%) than fathers of non-disabled children. A large proportion of disabled children were boys (70%) and had disability level 1 (47%). After adjusting for covariates, the odds ratio (OR) of having psychological distress (OR, 1.53; 95% CI, 1.19–1.97) and poor subjective health status (OR, 1.78; 95% CI, 1.34–2.36) among fathers of disabled children is significantly higher compared to fathers of non-disabled children. Unemployed fathers had a higher odds ratio of psychological distress (OR, 3.07; 95% CI, 2.49–3.79) and poor subjective health status (OR, 4.90; 95% CI, 3.95–6.09) compared to regular working fathers. Fathers of children with disabilities need greater physical and mental health and wellbeing support. They should be provided with additional support not just for their mental but also their subjective wellbeing.

Background: There have been numerous reports on the effects of paternal childcare on children’s behavioral development. However, little is known about these effects in Asian countries such as Japan, where fathers do not have sufficient time for childcare due to long working hours. This study explored the association between paternal childcare during toddlerhood in terms of childcare hours and the type of caregiving behavior and subsequent behavioral problems in children aged 5.5 years, stratified by sex.Methods: We analyzed data from the Longitudinal Survey of Newborns in the twenty-first Century (2001–2006), a population-based cohort survey in Japan (N = 27,870). Paternal childcare was assessed at 18 months in terms of paternal childcare hours on weekdays or weekends and the frequency of each type of childcare (feeding, changing diapers, bathing, putting the child to sleep, playing with the child at home, and taking the child outside). Based on the frequency or lack of paternal involvement, six categories of child behavioral problems were assessed when the children were 5.5 years old. Logistic regression analysis was applied to account for the known confounding variables.Results: Longer paternal childcare hours, on both weekdays and weekends in toddlerhood, had a protective effect on behavioral problems at 5.5 years of age. The dose-effect relationships were found between the frequency of fathers taking their children outside and behavioral problems in boys, and the frequency of fathers playing with their children at home and behavioral problems in both boys and girls.Conclusions: Paternal childcare during toddlerhood could prevent subsequent behavioral problems in children. Several specific paternal caregiving behaviors, such as taking their children outside and playing with them at home, may play an important role in preventing subsequent behavioral problems.

Eating behavior is an important aspect for dietary quality and long-term health. This study examined associations between eating vegetables first at a meal and food intakes among preschool children in Tokyo, Japan. We used cross-sectional data of 135 preschool children from seven nursery schools in Adachi City, Tokyo, Japan. Caregivers completed a survey on child’s eating behaviors and a diet questionnaire. Linear regression was used to examine frequency of eating vegetables first at a meal and food intakes; percent difference and the corresponding 95% confidence interval (95% CI) were presented. Overall, 25.2% of children reported eating vegetables first at a meal every time, 52.6% sometimes, and 22.2% not often or never. In the multivariate analysis, higher vegetable intake remained significant after adjusting for other covariates (compared with the group of eating vegetables first not often or never, the group reported sometimes: 27%, 95% CI: 0–63%; the group reported every time: 93%, 95% CI: 43–159%). No significant difference in intake by frequency categories of eating vegetables first was observed for other food groups, including fruits, meat, fish, cereals, and sweets. Children eating vegetables first at a meal more was associated with higher total intake of vegetables compared with children who did not eat vegetables first, among Japanese preschool children.