Maternal protein intake in early pregnancy and child development at age 3 years.

BACKGROUND: The current study aimed to assess the association between low maternal protein intake during pregnancy and child developmental delay at age 3 years. METHODS: This research used data obtained from the Japan Environment and Children's Study. In total, we analyzed 77,237 mother-child pairs. Dietary intake was assessed using the Food Frequency Questionnaire. Developmental outcomes at age 3 years were evaluated with the Japanese version of the Ages and Stages Questionnaire, Third Edition. A multivariate logistic regression analysis was performed to assess the association between maternal protein intake during pregnancy and child development delays at age 3 years. RESULTS: Based on the protein-to-total energy intake ratio during early pregnancy, the participants were categorized into three groups: <9.39% (>2 standard deviation below the mean), the severely low protein (SLP) group; 9.39-<13%, the low protein group; and ≥13%, the normal protein group. After adjusting for potential confounding factors, SLP intake was found to be significantly correlated with a higher risk of developmental delay according to the communication, fine motor and problem-solving skill domains. CONCLUSIONS: SLP intake caused by inadequate diet during early pregnancy was associated with a higher risk of child developmental delay at age 3 years. IMPACT: Animal studies have shown that maternal protein restriction during pregnancy and lactation causes abnormal brain development among offspring. Birth cohort studies to date have not assessed the effects of maternal low protein exposure during pregnancy on child development. Severely low protein intake during early pregnancy was associated with a higher risk of child developmental delay at age 3 years. Since nutritional imbalance in early pregnancy affects not only fetal growth but also postnatal neurodevelopment, nutritional management before pregnancy is considered important.

Association of influenza vaccination or influenza virus infection history with subsequent infection risk among children: The Japan Environment and Children's Study (JECS).

We measured the association between history of influenza vaccination by age 2 years and influenza virus (IFV) infection at ages 3 and 4 years by relative risk reduction. We also examined the association between history of IFV infection by age 2 years and recurrent IFV infection at age 3 years. This study included 73,666 children from a large Japanese birth cohort. Among children vaccinated never, once or twice when aged under 2 years, 16.0%, 10.8% and 11.3%, respectively, had been infected with IFV by age 3 years, and 19.2%, 14.5% and 16.0%, respectively, by age 4 years. Compared with no history of influenza vaccination, vaccination at ages 1 and/or 2 years reduced the risk of IFV infection at age 3 by 30%-32% and at age 4 by 17%-24%. The relative risk of recurrent IFV infection at ages 3 and 4 years increased in proportion to the number of prior infections by age 2. One-season-prior influenza vaccination history reduced the IFV infection risk at age 3 years by 25%-42%. Influenza vaccination most effectively protected children at age 3 who lacked older sibling(s) and did not attend nursery school. One-season-prior IFV infection increased the relative risk of recurrent infection at age 3 years (1.72-3.33). In conclusion, influenza vaccination-induced protection may partly extend to the next season. Owing to the relative risk reduction by influenza vaccination and the increased relative risk of IFV infection from prior-season infection, annual influenza vaccination is recommended.

Infantile peanut introduction and peanut allergy in regions with a low prevalence of peanut allergy: the Japan Environment and Children's Study (JECS).

BACKGROUND: In regions with a high prevalence of peanut allergy (PA), there is a consensus that the introduction of peanuts in early infancy is preventive against the development of PA. However, few studies have investigated whether the introduction of peanuts to infants is associated with PA in regions with a low prevalence of PA, including Japan. METHODS: We used data from 74,240 mother-child pairs who participated in the Japan Environment and Children's Study, a prospective birth cohort recruited between January 2011 and March 2014. A logistic regression model was used to analyze the association between infantile peanut introduction and PA at the age of 4 years with non-infantile peanut introduction as the reference group, adjusted for potential confounders. RESULTS: The percentage of infantile peanut introduction was 4.9% (n=3294) and 286 (0.4%) participants had allergic symptoms to peanuts at 4 years of age. Of all participants, 129 (0.2%) had PA at 4 years of age, which was defined as allergic symptoms and sensitization to peanuts. Those with infantile peanut introduction had a lower prevalence of PA than those without infantile peanut introduction, although this did not reach statistical significance (adjusted odds ratio: 0.53, 95% confidence interval, 0.17-1.68). Sensitivity analysis using IgE-mediated symptoms caused by peanuts as the outcome showed a similar result in relation to infantile peanut introduction. CONCLUSIONS: In countries with a low prevalence of PA, the effect of infantile peanut introduction on PA prevention was unclear.

A nationwide, prospective, cohort study on exogenous oxytocin and delays in early child development: the Japan environment and children's study.

Although it remains debatable, exogenous oxytocin, commonly used for labour induction and augmentation, reportedly increases risks of neurodevelopment delay, attention-deficit/hyperactivity disorder, and autism spectrum disorder among children prenatally exposed to exogenous oxytocin. However, only few studies have objectively examined exogenous oxytocin's impact on early childhood development through scoring evaluations. This study investigated the association between exogenous oxytocin exposure and neurodevelopment in 3-year-old children using the Ages and Stages Questionnaires, Third Edition. In this nationwide prospective cohort study, we extracted data from 104,062 foetal records regarding exogenous oxytocin use during labour from the Japan Environment and Children's Study. Participants completed questionnaires throughout the pregnancy and postpartum periods. Outcomes comprised the developmental status less than each cut-off value for the five domains of the Ages and Stages Questionnaire, Third Edition. We conducted multivariable logistic regression analyses on the data of 55,400 children after controlling for confounders. Among the 55,400 included women, 19.0% (n = 10,506) used exogenous oxytocin during labour and 81.0% (n = 44,894) did not. Children exposed to exogenous oxytocin showed no significantly increased risk of developmental delay in any domain (communication: odds ratio [OR] 1.04, 95% confidence interval [CI] 0.92-1.16; gross motor: OR 0.97, 95% CI 0.87-1.08; fine motor: OR 1.00, 95% CI 0.92-1.09; problem-solving: OR 1.02, 95% CI 0.94-1.11; personal-social: OR 0.91, 95% CI 0.80-1.03).   Conclusion: Exogenous oxytocin for labour induction did not adversely affect early childhood development. Further studies accounting for the degree of exogenous oxytocin exposure are required to confirm these results. What is Known: • In developed countries, labour is induced in 20-25% of all pregnancies, for which oxytocin is commonly used. • Studies have associated risks of neurodevelopment delay, attention-deficit/hyperactivity disorder, and autism spectrum disorder with exposure to exogenous oxytocin. What is New: • Evaluation with the Ages and Stages Questionnaire, Third Edition, revealed that exogenous oxytocin use did not adversely affect early childhood development. • This prospective study reinforced the lack of evidence of an association between exogenous oxytocin use and early childhood development after adjustment for confounding and rigorous bias elimination.

Gap between the concerns of healthcare professionals and parents' perceptions regarding dietary habits for 18-month- and 3-year-old children in Japan.

BACKGROUND: A gap has been reported between healthcare professionals' (hereafter "professionals") recognition of preschool children's diets and parents' perception of concern. This study investigated the gap between the concerns reported by professionals and parents' perceptions regarding health and dietary habits by age (18 months and 3 years) and gender in Japan. METHODS: The study design consisted of a cross-sectional, multilevel survey. The request letters were sent to all households with target children with the cooperation of local governments. After obtaining written informed consent from parents, questionnaires were distributed to them. The survey included 30 items on children's concerns about health and dietary habits. At the health checkup, parents indicated whether they were concerned in response to each item, and responded child's height and weight and birth height and weight. Next, the professionals provided counseling to the parents at a health checkup. After that, the professionals noted their concerns in response to the same 30 items as those given to parents. The participation rates were 82.9% (18 months) and 82.8% (3 years). Data of 239 persons for 18 months and 223 persons for 3 years old were analyzed. In the statistical analysis, the items that were judged as concerning by professionals but not by parents were identified; likewise, the items that were of concern to parents but not to professionals were identified. Sensitivity, false negative rate, specificity, false positive rate, and Youden index were calculated to analyze the discordance rate for each item. RESULTS: Many parents in this study were concerned about the issues that professionals did not consider to be concerning. Moreover, the parents worried about more issues for 3-year-olds than for 18-month-olds. The items for which ≥ 10 professionals indicated concerns and with higher discordance between the professionals and parents for both boys and girls were "picky eating" for 18-month-olds and "inconsistent amount of food" for 3-year-olds. CONCLUSIONS: The concerns that professionals have with respect to children's diets and the things that parents worry about show gaps. It might be necessary to provide professional counseling for parents to develop a correct understanding of their children's dietary habits.

Effect of birth season on allergic rhinitis and cedar pollinosis considering allergen and vitamin D exposure: The Japan Environment and Children's study (JECS).

BACKGROUND: The relationship between the season of birth, allergen sensitization, and allergic rhinitis have been inconsistent, and there are no studies that simultaneously consider vitamin D and allergen exposure. This study aimed to determine the associations between the season of birth, house dust mite (HDM) and Japanese cedar pollen (JCP) sensitization, and allergic rhinitis and pollinosis, while taking vitamin D levels and allergen exposure into account. METHODS: This study included 4323 participants in the Sub-Cohort Study of the Japan Environment and Children's Study. A logistic regression model was used to analyze the association between the season of birth and sensitization to JCP or HDM (judged by specific immunoglobulin E) at age 2 and allergic rhinitis or pollinosis at age 3, adjusted for HDM or JCP exposure and vitamin D levels with potential confounders. RESULTS: Participants born in spring or summer were more likely to have pollinosis than were those born in winter (adjusted odds ratio [aOR]: 2.08, 95% confidence interval [CI]: 1.13-3.82 for spring; aOR: 1.89, 95% CI: 1.03-3.47 for summer). Participants born in summer were more likely to have HDM sensitization than were those born in winter (Der p 1, aOR: 1.53, 95% CI: 1.10-2.15; Der f 1, aOR: 1.44, 95% CI: 1.03-2.01). Exposure to JCP and HDM were associated with pollinosis and HDM sensitization, respectively. CONCLUSIONS: Spring and summer births were associated with the development of pollinosis, and summer birth was associated with HDM sensitization, even when vitamin D and allergen exposure were considered. Further studies on mechanisms other than vitamin D and allergen exposure are required.

Prenatal Negative Life Events and Childhood Allergies: The Japan Environment and Children's Study (JECS).

BACKGROUND: It is inconclusive whether prenatal negative life events are a risk for the development of allergic diseases in children or whether social capital modifies the association. The objective of this study was to examine whether women's experiences of such events during pregnancy were associated with the development of allergic diseases in their offspring at 3 years old and whether social capital moderated this association. METHODS: We used data from 81,337 mother-child pairs who participated in the Japan Environment and Children's Study. This is a prospective birth cohort recruited between January 2011 and March 2014. We examined the associations between prenatal maternal negative life events (e.g., bereavement, financial, and marital problems) during pregnancy and allergic diseases (asthma, eczema, and food allergies) in children after adjustment for covariates using multivariate logistic regression. We also examined interactions between these life events and social capital, measured as two items, social cohesion and social support. RESULTS: Prenatal negative life events were significantly associated with doctor-diagnosed asthma at 3 years old with a dose-response relationship (one life event vs. none: adjusted odds ratio 1.13, 95% confidence interval [CI]: 1.07-1.20; two life events vs. none: adjusted odds ratio 1.24, 95% CI: 1.13-1.36; three or more life events vs. none: adjusted odds ratio 1.26, 95% CI: 1.10-1.46; p for trend <0.01). Similar results were observed for eczema and food allergies. There were no interactions between life events and social capital. CONCLUSION: Prenatal negative life events may be a risk factor for allergies in children. There was no modification of the effect of these events by social capital.

Association between Household Income and Allergy Development in Children: The Japan Environment and Children's Study.

BACKGROUND: Socioeconomic status has been found to be associated with allergic diseases in children, but results are inconsistent. This study aimed to assess the association between household income and the development of allergic disease in children at 3 years old. METHODS: We used data from 72,180 participants from the Japan Environment and Children's Study, which is a prospective birth cohort study with participants recruited from January 2011 to March 2014. We examined the associations between household income and allergic diseases (asthma, eczema, and food allergies) in children, adjusting for covariates using multivariate logistic regression. RESULTS: The percentages of doctor-diagnosed allergies at 3 years old were 7.5% for asthma, 7.2% for eczema, and 6.2% for food allergies. Children from households with an annual income of <2 million yen (approx. 18,000 USD) had a significantly higher risk of doctor-diagnosed asthma and eczema than those from households with an income of 4-6 million yen. The adjusted odds ratios (aORs) were 1.17 (95% confidence interval [CI] 1.03-1.34) and 1.21 (95% CI 1.06-1.39). Children from households with an income of >6 million yen tended to have an increased risk of food allergies (aOR 1.07, 95% CI 0.98-1.15). CONCLUSION: Low household income was a risk for doctor-diagnosed asthma and eczema, suggesting that public health professionals should recognize low-income groups as vulnerable populations for these conditions.

Prenatal occupational disinfectant exposure and childhood allergies: the Japan Environment and Children's study.

BACKGROUND: Disinfectants are widely used in the medical field, particularly recently because of the coronavirus pandemic, which has led to an increase in their use by both medical professionals and the general population. The objective of this study was to examine whether occupational disinfectant use during pregnancy was associated with the development of allergic disease in offspring at 3 years. METHODS: We used data from 78 915 mother/child pairs who participated in the Japan Environment and Children's Study, which is a prospective birth cohort recruited between January 2011 and March 2014. We examined the associations between maternal disinfectant use during pregnancy and allergic diseases (asthma, eczema and food allergies) in children after adjustment for covariates including maternal postnatal return to work when the child was 1 year old by multivariate logistic regression. RESULTS: Compared with those who never used disinfectants, participants who used disinfectant every day had a significantly higher risk of asthma in their offspring (adjusted OR 1.18, 95% CI 1.05 to 1.33 for 1-6 times a week; adjusted OR 1.26, 95% CI 1.05 to 1.52 for every day). The associations between disinfectant exposure and eczema were similar to those of asthma (adjusted OR 1.16, 95% CI 1.02 to 1.31 for 1-6 times a week; adjusted OR 1.29, 95% CI 1.06 to 1.57 for every day). We found a significant exposure-dependent relationship (p for trend <0.01). There were no significant associations between disinfectant use and food allergies. CONCLUSION: Disinfectant use by pregnant women may be a risk factor for asthma and eczema in offspring. As disinfectants are an effective tool in the prevention of infectious diseases, replication of this study and further research into the mechanisms are warranted.

Mother's iodine exposure and infants' hypothyroidism: the Japan Environment and Children's Study (JECS).

In this study, we aimed to determine the association of neonatal/post-neonatal hypothyroidism with mother's iodine exposure, especially povidone iodine disinfection, and hysterosalpingography. Participants were mother-child pairs in a Japanese birth cohort (n = 100,286). Risk factors of hypothyroidism were supplement intake, seaweed intake, other daily iodine intake, povidone iodine disinfection at delivery, and maternal history of hysterosalpingography, thyroid disease (Graves' disease and Hashimoto's thyroiditis), and medication (thiamazole and levothyroxine). Congenital hypothyroidism (CH) at age 1 year was assessed using a questionnaire. Transient hypothyroidism was defined as elevated thyroid stimulating hormone level at birth and absence of CH at age 1 year. The incidence of CH at age 1 year per 100 children was 1.1 for those born at 22-30 weeks' gestation, 0.17 following povidone iodine disinfection, and 0.07, 0.95, 0.81, 1.17, and 1.15 with a maternal history of hysterosalpingography, Graves' disease, Hashimoto's thyroiditis, thiamazole use, and levothyroxine use, respectively. Odds ratios (95% confidence intervals) of CH at age 1 year for povidone iodine disinfection, hysterosalpingography history, maternal Graves' disease, and maternal Hashimoto's thyroiditis were 1.13 (0.71-1.79), 0.47 (0.07-3.36), 7.06 (3.70-13.5), and 5.93 (2.90-12.1), respectively. For transient hypothyroidism for povidone iodine disinfection and hysterosalpingography history, these values were 1.99 (1.51-2.62) and 0.63 (0.20-1.96), respectively. Maternal thyroid disease greatly increased neonatal/post-neonatal hypothyroidism risk. Povidone iodine disinfection may increase transient hypothyroidism risk but not the risk at 1 year of age. Hysterosalpingography does not increase hypothyroidism risk from birth to age 1 year.

Social isolation among mothers caring for Infants in Japan: findings from the Nationwide Survey of healthy parents and children 21.

BACKGROUND: Child-rearing isolation may increase the risk of child abuse and negatively affect child development owing to increased urbanization and a decline in family and community support systems. PURPOSE: This study aimed to identify the prevalence of child-rearing isolation and the related sociodemographic factors among mothers in Japan using data from the Final Survey of Healthy Parents and Children 21. PARTICIPANTS: Mothers of young children attending their health checkups. METHODS: Multivariate logistic regression models assessed the association between child-rearing isolation and socio-demographic variables. Data from 69,337 women were analyzed. RESULTS: Mothers who experienced child-rearing isolation comprised 0.2% of all participants. Mothers who were 35 to 39 years old at childbirth (OR = 1.6, CI[1.0, 2.4], p = .036), were unemployed (OR = 1.7, CI[1.3, 2.4], p = .001), had experienced financial difficulty (OR = 1.8, CI[1.3, 2.5], p < .001), had husbands with limited participation in child-rearing (OR = 5.7, CI[4.2, 7.9], p < .001), lived in special wards in the Tokyo Metropolis (OR = 4.2, CI[2.2, 8.3], p < .001), had child abuse concerns (OR = 2.1, CI [1.5, 2.9], p < .001), and had no time to relax with their child (OR = 4.5, CI [3.1-6.7], p < .001) exhibited higher odds ratios for child-rearing isolation, compared to mothers who did not exhibit these characteristics. CONCLUSIONS: Findings showed the impact of urban living on maternal health and the influence of isolation on mothers' anxiety about child-rearing and their potential for child maltreatment. The importance of fathers' involvement in child-rearing in preventing maternal child-rearing isolation was highlighted.

Association of egg protein levels in dust with allergy status and related factors.

BACKGROUND: Levels of peanut protein in dust have been reported to be associated with sensitization and allergy to it, so controlling food protein in dust may help prevent food allergy. However, studies of factors associated with egg protein levels in dust are scarce. This study aimed to determine the factors contributing to egg protein levels in dust. METHODS: This cross-sectional study included 159 participants in the Sub-Cohort Study of the Japan Environment and Children's Study in Yamanashi Prefecture at a 6 year follow up. House dust at 6 years was collected and egg protein concentrations were measured for whole egg protein. Household factors, including the maternal frequency of egg consumption, were assessed by questionnaires. A linear regression model was used to analyze the effect of household environmental factors on egg protein in dust. RESULTS: In multivariate analysis, frequent maternal egg consumption (≥5 times a week) was associated with higher egg protein concentrations in house dust (ß = 0.96, P = 0.01). The egg protein load was significantly associated with a higher number of cohabitants (≥5, ß = 0.85, P = 0.02) in addition to frequent maternal egg consumption. Among the participants, 140 (88.1%) had no egg allergy, 15 (9.4%) were egg tolerant, and 4 (2.5%) had an egg allergy at 6 years old. There was no significant association between the current egg allergy status and egg protein concentrations in dust. CONCLUSIONS: The frequency of maternal egg consumption and the number of inhabitants are contributing factors to egg protein levels in dust.

Gestational body weight gain and risk of low birth weight or macrosomia in women of Japan: a nationwide cohort study.

OBJECTIVE: Both maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG) influence maternal and pediatric outcomes. We sought to clarify the impact of prepregnancy BMI-specific GWG and its patterns on the risk of low birth weight (LBW) or macrosomia using data from a large nationwide study in Japan. METHODS: This cohort study (n = 98,052) used data from the Japan Environment and Children's Study (JECS). The outcome variables in this study were LBW and macrosomia. We stratified the subjects into groups according to prepregnancy BMI. RESULTS: GWG from pre-pregnancy to the first trimester had a small effect on the risk of LBW and macrosomia. From the first to second trimesters, insufficient GWG was associated with the risk of LBW, and from the second trimester to delivery, a GWG of less than 2 kg was associated with the risk of LBW. These associations were commonly observed in all prepregnancy BMI categories. Irrespective of the GWG from pre-pregnancy to the first trimester, GWG from the first to second trimesters affects LBW and/or macrosomia. Irrespective of the GWG from the first to second trimesters, GWG from the second trimester to delivery affects LBW and/or macrosomia. LBW or macrosomia was associated with the prevalence of a sustained low or high BMI percentile until three years of age, respectively. CONCLUSIONS: The present large national cohort study indicates that the risk of LBW or macrosomia is associated with GWG in women in Japan; the significance of this risk depends on the GWG patterns.

Association between gestational hair dye use and allergies at 3 years old: the Japan environment and Children's study.

BACKGROUND: Hair dye use frequently induces allergic contact dermatitis, and on rare occasions induces immunoglobulin E-mediated immediate urticaria, anaphylaxis, and asthma. The effects of hair dye use during pregnancy on offspring have been studied for carcinogenicity, but not for development of allergies. This study aimed to assess the association between hair dye use during pregnancy and allergic disease in children at 3 years old. METHODS: Data of 77,303 participants from the Japan Environment and Children's Study, which is a prospective birth cohort recruited from January 2011 to March 2014, were used. We examined the associations between using hair dye during pregnancy and allergic diseases (food allergy, asthma, atopic dermatitis and allergic rhinitis) in children after adjustment for covariates by multivariable logistic regression. RESULTS: Among mothers who were exposed to hair dye during pregnancy, 50.0% were exposed in hair salons, 21.3% had home use, and 9.5% had occupational exposure. The percentages of doctor-diagnosed allergies at 3 years old were 6.3% for food allergies, 7.7% for asthma, 7.3% for atopic dermatitis, and 4.6% for allergic rhinitis. In univariable analyses, hair dye use at home and occupational exposure was significantly associated with asthma respectively (odds ratio [OR] 1.15, 95% CI 1.07-1.24 for at home; OR 1.18, 95% CI 1.08-1.28 for occupational exposure). Hair dye use at home were significantly associated with doctor-diagnosed allergic rhinitis at 3 years old (OR 1.12, 95% CI 1.02-1.22). After adjustment for covariates, these associations for asthma decreased and were no longer significant (aOR 1.06, 95% CI 0.98-1.14 for at home; aOR 1.09, 95% CI 1.00-1.20 for occupational exposure, p = 0.057), also for allergic rhinitis (aOR 1.07, 95% CI 0.97-1.19). Doctor-diagnosed allergic rhinitis at 3 years old was significantly associated with hair dye use at home in the most frequent use group (aOR for quite often versus never 1.78, 95% CI 1.22-2.60). CONCLUSION: Both home and occupation use of hair dye during pregnancy showed a trend of increased odds of allergic rhinitis and asthma in offspring at 3 years. However, the only association that reached significance was in frequency of use analyses between the highest frequency of home hair dye users and allergic rhinitis.

Association between preterm birth and maternal allergy considering IgE level.

BACKGROUND: The aim of this study was to explore the association between maternal allergies and preterm birth by different total immunoglobulin E (IgE) levels. METHODS: Data of 81 791 pregnant women from the Japan Environment and Children's Study, a prospective birth cohort, were used. Maternal allergic diseases, including a history of bronchial asthma (BA), atopic dermatitis (AD), and allergic rhinitis (AR), were obtained by self-administered questionnaires. Total serum IgE levels were measured at the first trimester and obstetrical outcomes from medical records transcripts were analyzed. The association between maternal allergic disease and obstetric outcome, including threatened abortion, preterm labor, early preterm birth (22-33 weeks), and late preterm birth (34-36 weeks), were examined by logistic regression. Subgroup analyses were performed by IgE level. RESULTS: Maternal BA and AR were associated with an increased risk of threatened abortion and preterm labor, but high total IgE level was associated with a decreased risk of preterm labor. There was little difference in associations between allergic disease and threatened abortion and preterm labor by total IgE levels. Although there was no significant association between allergic disease and preterm birth, if total IgE was high, AR was significantly associated with a decreased risk of early preterm birth (adjusted odds ratio, 0.60; 95% confidence interval 0.43-0.86). There was significant evidence for differences associated with total IgE levels (P-values for the interaction of the effects of AD and AR on early preterm birth were 0.039 and 0.015, respectively). CONCLUSIONS: The effect of allergy on preterm birth might differ depending on the total IgE level.

[Relationship between economic disparity and eating habits of 3-year-old children].

Objectives　This study aimed to clarify the relationship between economic disparity and eating habits of young children to explore the support that should be provided to families with young children.Methods　We conducted an anonymous self-administered questionnaire survey of parents who brought their children to the 3-year-old health checkup in four wards in City A. Questionnaire items examined the children's eating habits and the childrearing environment, such as the parents' socioeconomic status. Of 1,150 parents asked to participate in the survey, 616 responded (response rate: 53.6%). Invalid questionnaires (e.g., with missing answers) were eliminated. The remaining 498 parents (effective response rate: 80.8%) were classified into two groups to examine the association of household financial status with their 3-year-old eating habits: the relative poverty group and the non-relative poverty group. The groups were divided according to the poverty line of the Comprehensive Survey of Living Conditions. Statistical analysis was performed using Fisher's exact test and the Mann-Whitney U test. Eating habits that were identified to be associated with relative poverty were further tested using logistic regression analysis.Results　Analysis of the children's eating habits in the two groups revealed that, compared with the non-relative poverty group, there was a higher proportion of 3-year-olds who ate vegetables less than 6 days a week (P=0.003) and who consumed snacks 6 days or more per week (P=0.034) in the relative poverty group. The associations of relative poverty with vegetable intake less than 6 days a week and snack consumption 6 days or more a week remained significant after adjusting for parents' age, highest educational attainment, and subjective views on the everyday economic situation. Regarding the childrearing environment, the relative poverty group had a higher proportion of parents who were younger than 30 years of age (P<0.001) and in single-parent households (P=0.007). The relative poverty group had a higher proportion of parents whose highest education level was high school (P<0.001). Furthermore, the subjective view of the everyday economic situation was more negative in the relative poverty group (P<0.001).Conclusion　Economic disparity was related to the eating habits of 3-year-old children. The study results indicate that identifying families with financial difficulties during pregnancy and childbirth is necessary to support them early on so that young children can acquire healthy eating habits.

Municipality-Level Checklist to Promote Parental Behaviors Related to Prevention of Unintentional Injury in Young Children: A Multilevel Analysis of National Data.

BACKGROUND: Unintentional injury is a major cause of morbidity and mortality among young children in developed countries. In this national study, we examined the role of municipality-level safety checklist implementation for reducing risky child-safety-related parental behaviors. METHODS: Nationwide data were collected to evaluate the impact of the Healthy Parents and Children 21 initiative of the Japanese government. Questionnaires related to safety checklist implementation were administered to a random sample of municipal offices and to parents at the child's routine 1.5-year health exam on parental behaviors related to child safety. Adjusting for municipality and individual-level variables, multilevel analysis was used to examine the relationship between municipality checklist implementation (4-month health exam) and six child-safety-related parental behaviors at the 1.5-year health exam. RESULTS: Families (n = 23,394) across 371 municipalities in Japan were included in this study; 5.6% of municipalities implemented a child safety intervention. Living in a municipality with a checklist intervention was associated with reduction in certain risk behaviors (not keeping tobacco/ashtray and candy out of the reach of infants, not using a car seat, not having a lock on bathing room door). However, after additionally taking into account municipality-level residual effects, only the "tobacco" behavior showed association with municipality of residence (Interval odds ratio, 0.25-0.94) and others were weak in the context of other potential municipality-level influences. CONCLUSIONS: A municipality-level intervention taking a checklist-based approach at the 4-month health exam in Japan appears to promote certain child safety behaviors in parents with children around 1.5 years of age.

Prevalence of and factors associated with unplanned pregnancy among women in Koshu, Japan: cross-sectional evidence from Project Koshu, 2011-2016.

BACKGROUND: Unplanned pregnancy is a public health issue with adverse consequences for maternal and neonatal health. In Japan, the prevalence of unplanned pregnancy was 46.2% in 2002. However, few studies have investigated this topic, and there is little recent data from Japan. We described and examined the prevalence and determinants of unplanned pregnancy among rural women in Japan from 2011 to 2016. METHODS: We used cross-sectional data from a community-based cohort study (Project Koshu). Data were collected from 2011 to 2016 via a self-report questionnaire included in the Maternal and Child Health Handbook of Japan. Pregnancy intention was measured as a binary variable (planned or unplanned). Univariate and multivariate logistic regression analyses were performed to examine factors associated with unplanned pregnancy, with results reported as odds ratios (ORs) and 95% confidence intervals (CIs). We conducted sensitivity analyses with different definitions of pregnancy intention to assess the robustness of the results. The significance level was set at 5%. RESULTS: Of the 932 participants (mean ± standard deviation age at baseline: 31.3 ± 5.2 years), 382 (41%) pregnancies were reported as unplanned. The multivariate analyses showed that maternal age (+ 1 year: OR = 0.94, 95% CI: 0.92-0.97, p <  0.001), 'other' family structure (OR = 2.76, 95% CI: 1.12-6.76, p = 0.03), three or more pregnancies (OR = 2.26, 95% CI: 1.66-3.08, p <  0.001), current smoking (OR = 2.60, 95% CI: 1.26-5.35, p = 0.01), balanced diet (OR = 0.62, 95% CI: 0.47-0.83, p <  0.001) and current depression (OR = 1.63, 95% CI: 1.24-2.16, p <  0.001) were strongly associated with unplanned pregnancy. These associations were consistent across definitions of pregnancy intention, supporting the robustness of our results. CONCLUSIONS: The prevalence of unplanned pregnancy in the study population was high (41%). Risk factors for unplanned pregnancy were age, number of pregnancies, smoking, having a balanced diet and current depression. These results suggest greater efforts are needed to enhance sex education for young people, improve access to family planning services and provide comprehensive health care for high-risk women to help reduce unplanned pregnancies.

Association of objectively measured physical activity and sedentary behavior with bone stiffness in peripubertal children.

INTRODUCTION: Physical activity (PA) is a key factor of bone mass acquisition in peripubertal children. Sedentary behavior (SB) has been shown to influence bone outcomes. This study aimed to examine the association between objectively measured PA and SB and bone stiffness in Japanese children. MATERIALS AND METHODS: Participants were fifth-grade children aged 10-11 years from Project Koshu. The stiffness index (SI) of the calcaneus was measured by quantitative ultrasound; PA and SB were evaluated by an accelerometer. Each PA parameter was divided into sex-specific tertile or stratified by recommended PA guideline [≥ 60 min/day of moderate-to-vigorous PA (MVPA)]. The SI was compared among PA and SB through analysis of covariance with Bonferroni correction. RESULTS: Of 174 children, complete data were obtained from 134 (60 boys and 74 girls). The SI in boys was higher in the highest tertile of MVPA than that in the other groups. A similar association was found in girls but was not significant. Children who met the PA guideline had higher SI than those who did not, but there was no significant difference. A negative relation was observed in girls, with the SI gradually decreasing along with increasing SB (p for trend = 0.038). This association was not observed among boys. CONCLUSION: This study suggests that MVPA is positively associated with bone stiffness in Japanese schoolchildren in boys and SB is negatively associated with that in girls. Reducing SB might be a brief modifiable factor for preventing lower peak bone mass in girls, in addition to increasing MVPA.

Problematic Internet use and its associations with health-related symptoms and lifestyle habits among rural Japanese adolescents.

AIM: There have been concerns about the increase in problematic Internet use (PIU) and its impact on lifestyle habits and health-related symptoms, given the rapid spread of smartphones. This study aimed to clarify PIU prevalence over 3 years in the same area and investigate lifestyle and health-related factors related to PIU among junior high-school students in Japan. METHODS: Each year during 2014-2016, a survey was conducted with junior high-school students from a rural area of Japan (2014, n = 979; 2015, n = 968; 2016, n = 940). Young's Internet Addiction Test was used to assess participants' PIU. Students scoring 40 or higher on the Internet Addiction Test were classified as showing PIU in this study. The associations between PIU and lifestyle factors (e.g., exercise habits, weekday study time, and sleep time) and health-related symptoms (depressive symptoms and orthostatic dysregulation [OD] symptoms) were studied by logistic regression analyses. RESULTS: Over the 3 years, the prevalence of PIU was 19.9% in 2014, 15.9% in 2015, and 17.7% in 2016 without significant change. PIU was significantly associated with skipping breakfast, having a late bedtime (after midnight), and having OD symptoms among students from all grades. Sleepiness after awakening in the morning, less studying time, and depressive symptoms had significant positive associations with PIU, except among 1st grade junior high-school students. CONCLUSION: Our results suggest that PIU is related to decreased time spent sleeping, studying, and exercising and increased symptoms of depression and OD. Further investigations are needed to develop preventive measures for PIU.