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.

Supplementary information

The online version contains supplementary material available at 10.1007/s10995-022-03427-0.

Association Between Screen Time Exposure in Children at 1 Year of Age and Autism Spectrum Disorder at 3 Years of Age: The Japan Environment and Children's Study

IMPORTANCE

It is unclear to what extent the duration of screen time in infancy is associated with the subsequent diagnosis of autism spectrum disorder.

OBJECTIVE

To examine the association between screen time in infancy and the development of autism spectrum disorder at 3 years of age.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed data from mother-child dyads in a large birth cohort in Japan. This study included children born to women recruited between January 2011 and March 2014, and data were analyzed in December 2020. The study was conducted by the Japan Environment and Children's Study Group in collaboration with 15 regional centers across Japan.

EXPOSURES

Screen time at 1 year of age.

MAIN OUTCOMES AND MEASURES

The outcome variable, children diagnosed with autism spectrum disorder at 3 years of age, was assessed using a questionnaire administered to mothers of the participating children.

RESULTS

A total of 84 030 mother-child dyads were analyzed. The prevalence of children with autism spectrum disorder at 3 years of age was 392 per 100 000 (0.4%), and boys were 3 times more likely to have been diagnosed with autism spectrum disorder than were girls. Logistic regression analysis showed that among boys, when "no screen" was the reference, the adjusted odds ratios were as follows: less than 1 hour, odds ratio, 1.38 (95 % CI, 0.71-2.69; P = .35), 1 hour to less than 2 hours, odds ratio, 2.16 (95 % CI, 1.13-4.14; P = .02), 2 hours to less than 4 hours, odds ratio, 3.48 (95% CI, 1.83-6.65; P < .001), and more than 4 hours, odds ratio, 3.02 (95% CI, 1.44-6.34; P = .04). Among girls, however, there was no association between autism spectrum disorder and screen time.

CONCLUSIONS AND RELEVANCE

Among boys, longer screen time at 1 year of age was significantly associated with autism spectrum disorder at 3 years of age. With the rapid increase in device usage, it is necessary to review the health effects of screen time on infants and to control excessive screen time.

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.

High Incidence of Atopic Dermatitis among Children Whose Fathers Work in Primary Industry: The Japan Environment and Children's Study (JECS)

The hygiene hypothesis assumes a low incidence of allergic diseases in families engaging in farming work. However, a few studies have indicated rural life as a potential risk factor for atopic dermatitis (AD). Using a large Japanese birth cohort dataset, we calculated the accumulated incidence of AD in children aged 6 months and 1, 2, and 3 years by family business and the hazard ratio. We adjusted for confounding factors. The father's job was considered the family business. We analysed data on 41,469 father-child pairs at 6 months of age, 40,067 pairs at 1 year, 38,286 pairs at 2 years, and 36,570 pairs at 3 years. We found the highest accumulated incidence of AD among children with fathers engaged in primary industry, with 2.5% at the age of 6 months, 6.6% at 1 year, 12.0% at 2 years, and 15.4% at 3 years. Among primary industry occupations, forestry was associated with the highest incidence of AD across these ages. The hazard ratio of AD was also highest for children whose family business was primary industry. In conclusion, the highest incidence and hazard ratio of AD were observed among children whose fathers worked in primary industry.

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.

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 (β = 0.96, P = 0.01). The egg protein load was significantly associated with a higher number of cohabitants (≥5, β = 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.

Maternal Urinary Cotinine Concentrations During Pregnancy Predict Infant BMI Trajectory After Birth: Analysis of 89617 Mother-Infant Pairs in the Japan Environment and Children's Study

BACKGROUND

Clinical or epidemiological conclusions remain undecided on the direct effects of active and second-hand smoking during pregnancy on childhood obesity. Urinary cotinine (UC) concentration, an accurate and quantitative marker for smoking, may elucidate the dose-dependent relationship between smoking during pregnancy and childhood obesity. To analyze the relationship between UC concentration and smoking questionnaire (SQ) classes for active and second-hand smoking in pregnant mothers and trajectory of infant Kaup index (body mass index: BMI).

METHODS

This multicenter prospective cohort study was conducted using a list-wise complete set of 35829 among 89617 mother-infant singleton pairs, recruited between 2011 and 2014, in the Japan Environment and Children's Study (JECS). Pairs were categorized according to UC levels (1 to 4 classes) or SQ (0 to 4 classes).

RESULTS

Maternal BMI at delivery was the highest in UC class 4 (highest). Maternal and paternal education of ≥16 years and annual household income were lowest in UC class 4. Infant BMI was lower at birth, but trends in BMI and ΔBMI were higher from six to 36 months step-wise in the UC classes. The above tendency was observed in the list-wise complete dataset but was emphasized after multiple imputations and corrections of cofounders. UC concentration in five SQ classes largely fluctuated, and the relationship between SQ classes and trends in BMI and ΔBMI was not statistically significant.

CONCLUSION

Infants from high UC mothers had a low BMI at birth, increasing from six to 36 months of age. UC concentrations, but not smoking questionnaire classes, predict infant BMI trajectory, suggesting that active and second-hand smoking affect child obesity in a dose-dependent manner.

Factors of parental COVID-19 vaccine hesitancy: A cross sectional study in Japan

The eligibility of COVID-19 vaccines has been expanded to children aged 12 and above in several countries including Japan, and there is a plan to further lower the age. This study aimed to assess factors related to parental COVID-19 vaccine hesitancy. A nationwide internet-based cross-sectional study was conducted between May 25 and June 3, 2021 in Japan. The target population was parents of children aged 3–14 years who resided in Japan, and agreed to answer the online questionnaire. Parental COVID-19 vaccine hesitancy (their intention to vaccinate their child) and related factors were analyzed using logistic regression models. Interaction effects of gender of parents and their level of social relationship satisfaction related to parental vaccine hesitancy was tested using log likelihood ratio test (LRT). Social media as the most trusted information source increased parental vaccine hesitancy compared to those who trusted official information (Adjusted Odds Ratio: aOR 2.80, 95% CI 1.53–5.12). Being a mother and low perceived risk of infection also increased parental vaccine hesitancy compared to father (aOR 2.43, 95% CI 1.57–3.74) and those with higher perceived risk of infection (aOR 1.55, 95% CI 1.04–2.32) respectively. People with lower satisfaction to social relationships tended to be more hesitant to vaccinate their child among mothers in contrast to fathers who showed constant intention to vaccinate their child regardless of the level of satisfaction to social relationship (LRT p = 0.021). Our findings suggest that dissemination of targeted information about COVID-19 vaccine by considering means of communication, gender and people who are isolated during measures of social distancing may help to increase parental vaccine acceptance.

Elective cesarean delivery at term and its effects on respiratory distress at birth in Japan: The Japan Environment and Children's Study

BACKGROUND AND AIMS

Early-term birth between 37 and 38 weeks of gestation increases the risk of mortality and morbidity. This study investigated the status and impact of early-term birth among neonates born by cesarean section in Japan.

METHODS

All singleton live births that had data of gestational age at birth available in the Japan Environment and Children's Study (JECS), a nationwide birth cohort study launched in 2011, were eligible for this study. Neonates born by cesarean delivery at term without indications for early delivery were included to examine the association between early-term birth and respiratory distress at birth. The gestational age at birth was categorized as 37 weeks 0 day to 38 weeks 6 days (early-term), 39 weeks 0 day to 40 weeks 6 day (full-term), and 41 weeks 0 day to 41 weeks 6 days (late-term). Respiratory distress at birth included respiratory distress syndrome, transient tachypnea, and difficulty in breathing after birth. Univariable and multivariable analyses were performed using logistic regression models with a two-tailed significance level of 5%. All statistical analyses were performed using SAS, version 9.4, for Windows (SAS Institute, Cary, NC).

RESULTS

In total, 32 078 of 100 011 (32.1%) neonates had early-term birth. At 37 gestational weeks, 49.7% of the deliveries were via cesarean section, and half of the cesarean deliveries were due to a previous cesarean section. Among the 10 051 neonates born by elective cesarean delivery at term, neonates with early-term births were more likely to have respiratory distress at birth (adjusted odds ratio: 4.19; 95% confidence interval, 1.70, 10.34) than those born at full term.

CONCLUSIONS

Early-term birth is associated with a high risk of respiratory distress in births involving cesarean delivery without indication for early delivery. There is a need for guidelines for early delivery considering adverse effects of early-term births.

Association of glycated hemoglobin at an early stage of pregnancy with the risk of gestational diabetes mellitus among non-diabetic women in Japan: The Japan Environment and Children's Study

AIMS/INTRODUCTION

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy and is associated with adverse pregnancy outcomes. This study aimed to explore the associations between glycated hemoglobin (HbA1c) levels at the early stage of pregnancy and the GDM risk among non-diabetic women in a nationwide study in Japan. In addition, the relationship between GDM and adverse pregnancy outcomes was also analyzed.

MATERIALS AND METHODS

This cohort study (n = 89,799) used data from the Japan Environment and Children's Study. We stratified the participants into four groups according to HbA1c levels at an early stage of pregnancy. We investigated the association of HbA1c at an early stage of pregnancy with the risk of GDM, and of GDM with the risk of some representative adverse pregnancy outcomes, using the multiple logistic regression model with adjustment for potential confounders.

RESULTS

The adjusted odds ratio for GDM per 0.1 percentage point increase in HbA1c (%) was 1.20. The adjusted odds ratio for developing GDM was significantly increased in women from the HbA1c 5.0-5.4% category. GDM significantly increased the adjusted odds ratio for adverse pregnancy outcomes, such as hypertensive disorders of pregnancy, polyhydramnios and premature birth.

CONCLUSIONS

High-normal HbA1c levels at the early stage of pregnancy are significantly associated with GDM risk in women in Japan. GDM was significantly associated with adverse pregnancy outcomes.

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 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.

Central vein sign: A diagnostic biomarker in multiple sclerosis (CAVS-MS) study protocol for a prospective multicenter trial

The specificity and implementation of current MRI-based diagnostic criteria for multiple sclerosis (MS) are imperfect. Approximately 1 in 5 of individuals diagnosed with MS are eventually determined not to have the disease, with overreliance on MRI findings a major cause of MS misdiagnosis. The central vein sign (CVS), a proposed MRI biomarker for MS lesions, has been extensively studied in numerous cross sectional studies and may increase diagnostic specificity for MS. CVS has desirable analytical, measurement, and scalability properties. "Central Vein Sign: A Diagnostic Biomarker in Multiple Sclerosis (CAVS-MS)" is an NIH-supported, 2-year, prospective, international, multicenter study conducted by the North American Imaging in MS Cooperative (NAIMS) to evaluate CVS as a diagnostic biomarker for immediate translation into clinical care. Study objectives include determining the concordance of CVS and McDonald Criteria to diagnose MS, the sensitivity of CVS to detect MS in those with typical presentations, and the specificity of CVS among those with atypical presentations. The study will recruit a total of 400 participants (200 with typical and 200 with atypical presentations) across 11 sites. T2*-weighted, high-isotropic-resolution, segmented echo-planar MRI will be acquired at baseline and 24 months on 3-tesla scanners, and FLAIR* images (combination of FLAIR and T2*) will be generated for evaluating CVS. Data will be processed on a cloud-based platform that contains clinical and CVS rating modules. Imaging quality control will be conducted by automated methods and neuroradiologist review. CVS will be determined by Select6* and Select3* lesion methods following published criteria at each site and by central readers, including neurologists and neuroradiologists. Automated CVS detection and algorithms for incorporation of CVS into McDonald Criteria will be tested. Diagnosis will be adjudicated by three neurologists who served on the 2017 International Panel on the Diagnosis of MS. The CAVS-MS study aims to definitively establish CVS as a diagnostic biomarker that can be applied broadly to individuals presenting for evaluation of the diagnosis of MS.

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.

Temporal directional relationship between problematic internet use and depressive symptoms among Japanese adolescents: A random intercept, cross-lagged panel model

AIM

The results from research on the temporal directional relationship between problematic Internet use (PIU) and depressive symptoms are inconsistent. This study aimed to explore this relationship among junior high school students in Japan.

METHODS

Junior high/middle school students in the seventh grade (Time 1, [T1]) were recruited annually for 4 years starting in 2014; each cohort was followed up at 1 year (Time 2, [T2]) and 2 years (Time 3, [T3]). Three-year longitudinal panel data were collected from self-reported questionnaires that were completed by 1192 students (586 males and 606 females). Young's Internet Addiction Test and the Birleson Depression Self-rating Scale were used to assess participants' PIU and depressive symptoms, respectively. The temporal directional relationship between PIU and depressive symptoms was analyzed using the random intercept, cross-lagged panel model.

RESULTS

The mean of the Internet Addiction Test increased as grade level increased: 28.0 at T1, 30.7 at T2 and 32.6 at T3. There was a unidirectional positive effect from PIU at T2 to depressive symptoms at T3, but not vice versa. There was no directional effect from PIU at T1 to depressive symptoms at T2, nor any in the reverse.

CONCLUSION

Our findings suggest that PIU precedes depressive symptoms. Therefore, addressing PIU is a promising preventive measure for adolescent depression.

Association of the incidence of atopic dermatitis until 3 years old with birth month and with sunshine duration and humidity in the first 6 months of life: Japan Environment and Children's Study

OBJECTIVE

To compare the incidence of atopic dermatitis in children aged from 6 months to 3 years across birth seasons and climate conditions.

DESIGN

Cohort study.

SETTING

Fifteen regional centres across Japan.

PARTICIPANTS

A total of 100 304 children born from 2011 to 2014.

EXPOSURE

Birth month, and mean sunshine duration (short/long) and humidity (high/low) in the first 6 months of life.

PRIMARY OUTCOME MEASURE

Incidence of atopic dermatitis.

RESULTS

The highest incidence of atopic dermatitis was in children born in the months of October to December. The lowest incidence of atopic dermatitis was in the months of April to June and in periods with a long duration of sunshine and high humidity. Low humidity was significantly associated with a higher incidence of atopic dermatitis. However, this significant difference disappeared when the birth season and parental history of allergic disease were considered in multivariate analysis.

CONCLUSIONS

In Japan, being born in the late autumn to early winter months is associated with a risk of developing atopic dermatitis until the age of 3 years. Sunshine duration and humidity from birth to 6 months of age are not associated with the incidence of atopic dermatitis.

Comparison of Japan nurse practitioner-led care and physician trainee-led care on patients' length of stay in a secondary emergency department: A retrospective study

Aim

We compared Japan nurse practitioner‐led care and physician trainee‐led care in terms of patients' length of stay in a secondary emergency department in Japan.

Methods

This was a retrospective observational study, utilizing medical records. Participants (n = 1419; mean age = 63.9 ± 23.4 years; 52.3% men) were patients transferred to the emergency department by ambulance between April 2016 and March 2018 in western Tokyo. Multiple linear regression analyses were performed, with length of stay as the dependent variable and factors related to the length of stay, including medical care leaders, as the independent variable.

Results

Approximately half of the patients (n = 763; 53.8%) received Japan nurse practitioner‐led care. Patients' length of stay was significantly shorter, by 6 min, in the Japan nurse practitioner‐led care group, compared with the physician trainee‐led care group (unstandardized coefficient: −6.81; 95% confidence interval: −13.35 to −0.26; p < 0.05).

Conclusion

Patients' shorter length of stay in the Japan nurse practitioner group, compared with the physician trainee group, suggests that Japan nurse practitioners are not inferior to physician trainees in terms of the time spent to manage patients.

Prevalence of floating toe and its relationship with static postural stability in children: The Yamanashi adjunct study of the Japan Environment and Children's Study (JECS-Y)

Floating toe (FT) is a frequently seen condition in which a toe is inadequately in contact with the ground. Although toes play an important role in stabilizing standing posture and walking, many aspects of the effects of FT on the body remain unclear. To our knowledge, there have been no reports about the relationship between FT and postural stability, especially in children. This study aimed to clarify the prevalence of FT and its relationship with static postural stability in children. Of the 400 children aged 8 years who participated in our cohort study, 396, who were examined for static postural stability, were included in this study. Postural stability and FT were assessed using a foot pressure plate. The sway path length of the center of pressure and the area of the ellipse defined as the size of the area marked by the center of pressure, were measured as an evaluation of static postural stability. We calculated the "floating toe score (FT score: small FT score indicates insufficient ground contact of the toes)" using the image of the plantar footprint obtained at the postural stability measurement. The rate of FT was elevated at more than 90%, and the FT score in the eyes-closed condition was significantly higher than that in the eyes-open condition in both sexes. The FT score significantly correlated with the center of pressure path and area. Our results suggest that ground contact of the toes is not directly related to static postural stability in children, but it may function to stabilize the body when the condition becomes unstable, such as when the eyes are closed.

All-cause and cardiovascular disease mortality in underweight patients with diabetic nephropathy: BioBank Japan cohort

We aimed to determine mortality risk in underweight patients with diabetic nephropathy for microalbuminuria or macroalbuminuria. We analyzed mortality and death-cause data from BioBank Japan, with baseline years 2003-2007. We analyzed mortality rates from all causes and ischemic heart disease, according to body mass index (<18.5, 18.5-21.9, 22-24.9 and ≥25 kg/m² ). The mean (standard deviation) of patient age, body mass index, and glycated hemoglobin at enrollment was 61.6 years (11.7 years), 25.0 kg/m² (4.4 kg/m² ) and 7.7% (1.5%), respectively. Hazard ratios of all-cause and ischemic heart disease mortality were highest (1.79 [P = 0.0001] and 2.95 [P = 0.027], respectively) in patients with body mass index <18.5 kg/m² , as compared with body mass index 22-24.9 kg/m² . All-cause mortality risk for body mass index <18.5 kg/m² was similar to that for current smokers (hazard ratio 1.70, P < 0.0001). Underweight could be a predictor of mortality risk in patients with diabetic nephropathy for microalbuminuria or macroalbuminuria.

Caregivers' mental distress and child health during the COVID-19 outbreak in Japan

To clarify the physical and mental conditions of children during the coronavirus disease 2019 pandemic and consequent social distancing in relation to the mental condition of their caregivers. This internet-based nationwide cross-sectional study was conducted between April 30 and May 13, 2020. The participants were 1,200 caregivers of children aged 3-14 years. Child health issues were categorized into "at least one" or "none" according to caregivers' perception. Caregivers' mental status was assessed using the Japanese version of the Kessler Psychological Distress Scale-6. The association between caregivers' mental status and child health issues was analyzed using logistic regression models. Among the participants, 289 (24.1%) had moderate and 352 (29.3%) had severe mental distress and 69.8% of children in their care had health issues. The number of caregivers with mental distress was more than double that reported during the 2016 national survey. After adjusting for covariates, child health issues increased among caregivers with moderate mental distress (odds ratio 2.24, 95% confidence interval 1.59-3.16) and severe mental distress (odds ratio 3.05, 95% confidence interval 2.17-4.29) compared with caregivers with no mental distress. The results highlight parents' psychological stress during the pandemic, suggesting the need for adequate parenting support. However, our study did not consider risk factors of caregivers' mental distress such as socioeconomic background. There is an urgent need for further research to identify vulnerable populations and children's needs to develop sustainable social support programs for those affected by the outbreak.

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 between time-appropriate vaccinations in early childhood and individual and community-level factors in Japan]

Objective　Recently, in Japan, the compulsory vaccinations administered during early childhood have been becoming increasingly varied. As a result, the vaccination schedule has become complicated. In this study, we aimed to identify the association of time-appropriate vaccination during early childhood (dependent variable) with individual-level factors including socioeconomic status and having a family doctor. We also studied the association of time-appropriate vaccination with community-level factors including the number of pediatricians in a community.Methods　Multilevel logistic regression models were used for analysis. Time-appropriate BCG, DPT, and measles vaccinations were the dependent variables. Individual-level data were obtained through a survey of parents of 18-month-old children as part of the final evaluation of "Healthy Parents and Children 21"; community-level data were obtained through a survey of municipalities as part of the aforementioned final evaluation as well as through a national survey. There were 23,583 parents in 430 municipalities who were eligible for analysis.Results　Time-appropriate vaccination of infants was carried out by 88.3% of parents. The results of the multilevel logistic regression showed that time-appropriate vaccination was significantly lower for those who did not have a family doctor (adjusted odds ratio [AOR], 0.45; 95% confidence interval [CI], 0.36-0.55), the fourth or later birth order (0.23; 0.19-0.28), mothers aged less than 19 years at childbirth (0.17; 0.13-0.24), full-time working mothers (0.52; 0.47-0.58), and those under very difficult economic conditions (0.66; 0.57-0.77). Among community-level factors, only use of vaccination data by a municipality had a significantly negative association with the dependent variable.Conclusion　Not having a family doctor, the mother's young age, late birth order, poor economic status, and full-time working mothers were risk factors associated with delayed vaccinations. It is necessary to improve environments that promote infants having a family doctor as well as to promote special approaches toward families at risk for delayed vaccinations.