Cat and Dog Ownership in Early Life and Infant Development: A Prospective Birth Cohort Study of Japan Environment and Children's Study

Relationship between frequency of yogurt consumption at 1 year of age and development at 3 years of age: The Japan Environment and Children's Study

BACKGROUND

Multiple observational studies have demonstrated the health benefits of yogurt, which are considered due to yogurt's positive effects on the gut microbiota. It is also known that the intestinal microbiota is associated with cognitive and emotional functions. Although the intake of probiotics has been reported to improve neurodevelopmental symptoms in children, no large-scale studies have examined the association of yogurt consumption in early childhood with later neurodevelopmental status. In this study, we examined the association between frequency of such consumption at 1 year of age and the children's subsequent neurodevelopmental status.

METHODS

We studied children's dietary consumption of yogurt at age 1 year and their neurodevelopment at age 3 years from data gathered from70,276 mother-child pairs enrolled in the Japan Environment and Children's Study. We collected data from pregnant women whose consent was obtained after the study was explained to them at participating facilities in the target area. Frequency of yogurt consumption was categorized into 0, 1-2, 3-4, and ≥ 5 times/week based on a questionnaire about the child's diet completed by the mother. Developmental delay was assessed using the Ages and Stages Questionnaires, Third Edition (ASQ-3™) in five domains: communication, gross motor, fine motor, problem solving, and personal-social. Using the results of the group that did not consume yogurt as a reference, multivariate logistic regression analysis was performed to compare the neurodevelopment of children according to frequency of yogurt consumption. For the covariates, items related to the socio-economic background and children's neurodevelopment were selected with reference to previous studies.

RESULTS

Consumption of yogurt 1-4 times/week was associated with a reduced risk of developmental delay in all ASQ-3 categories(adjusted odds ratios, 0.71-0.87). However, the risk of developmental delay was not necessarily reduced with yogurt consumption ≥5 times/week (adjusted odds ratios, 0.84-0.96).

CONCLUSION

Yogurt consumption habits at 1 year of age were associated with a lower risk of developmental delay at 3 years of age. However, the association was less apparent when yogurt was consumed more frequently. Possible mechanisms by which yogurt intake affects neurodevelopment include neurotransmitters produced by intestinal bacteria as well as the suppression of intestinal inflammation through improvements in the intestinal environment. Regular intake of yogurt in early childhood may have a positive association with neurodevelopment, but it is hoped that clearer links will be found in the future through intervention studies.

Effects of dog ownership on children's social-emotional development: findings from the PLAYCE cohort study

INTRODUCTION

Dog ownership is common in families with children and could play a role in children's social-emotional development. This study used longitudinal data on dog ownership and changing dog ownership to investigate their effects on young children's social-emotional development.

METHODS

Parents reported family dog ownership when their child was aged 2-5 years and at 5-7 years. Children (n = 591) were assigned to a dog ownership group by combining their current and prior dog ownership status. The parent-report Strengths and Difficulties Questionnaire (SDQ) measured children's social-emotional development at 5-7 years. Analyses included linear, Poisson, and logistic regression and adjusted for socio-demographic factors.

RESULTS

Girls who acquired a dog had significantly higher peer problems scores than non-dog owner girls (exp(β) = 1.8; 95% CI 1.3, 2.6). Boys who acquired a dog had significantly lower peer problems scores than continuing non-dog owner boys (exp(β) = 0.5; 95% CI 0.3, 0.8). There were no other significant effects observed between dog ownership group and SDQ scores or the odds of having abnormal scores.

CONCLUSIONS

Overall, changing or continuing dog ownership status had minimal impact on young children's social-emotional development. Future longitudinal research should examine the effects of dog ownership on child development by family characteristics and attachment to the dog.

IMPACT

Dog acquisition was associated with higher peer problems for girls and lower peer problems for boys, but not the odds of having abnormal peer problems scores. Dog acquisition, dog loss, and continuing dog ownership status were not associated with other measure of social-emotional development. This study used longitudinal data to examine effects of dog ownership on child development. Overall, changing or continuing dog ownership status had minimal impact on young children's social-emotional development. Since dog ownership is selected into, longitudinal research is needed to confirm if changes in children's social-emotional development occur following changes in dog ownership.

Mechanisms of Social Attachment Between Children and Pet Dogs

An increasing body of evidence indicates that owning a pet dog is associated with improvements in child health and well-being. Importantly, the degree of the social bond between child and dog may mediate the beneficial outcomes of dog ownership. The formation of social bonds is an intrinsically dyadic, interactive process where each interactor's behavior influences the other's behavior. For this reason, it is critical to evaluate the biological mechanisms of attachment in both children and their pet dogs as a socially bonded pair. Here, we review the physical, mental, and emotional outcomes that are associated with pet dog ownership or interaction in children. We then discuss the evidence that suggests that the strength of a social bond between a child and their pet dog matters for maximizing the beneficial outcomes associated with pet dog ownership, such as possible stress-buffering effects. We review the existing literature on the neural and endocrinological mechanisms of social attachment for inter-species social bonds that form between human children and dogs, situating this emerging knowledge within the context of the mechanisms of intra-species bonds in mammals. Finally, we highlight the remaining open questions and point toward directions for future research.

Maternal dietary intake of fish and child neurodevelopment at 3 years: a nationwide birth cohort-The Japan Environment and Children's Study

Background

Results on the association between fish intake during pregnancy and a reduction in neurodevelopmental delays in children have been inconsistent, with some reports finding an association and others finding none. Because neurodevelopmental delays are more pronounced at the age of 3 years, their association needs to be examined at this age.

Methods

After exclusion and multiple imputation from a dataset comprising 104,057 records from the Japan Environment and Children's Study, logistic regression analysis was conducted in quintiles to evaluate the association between maternal fish intake during pregnancy and child neurodevelopment at age 3 years in 91,909 mother-child pairs. The Food Frequency Questionnaire (FFQ), validated in the Japan Public Health Center-Based Prospective Study for the Next Generation, was used to assess maternal fish intake during pregnancy. The Ages and Stages Questionnaires-3 was used to assess children's neurodevelopment in five domains: communication, gross motor, fine motor, problem-solving, and personal-social.

Results

Consistently lower odds were found for the highest vs. lowest quintile for the domains of communication, fine motor, problem-solving, and personal-social but not gross motor skills, with adjusted odd ratios (95% confidence intervals) of 0.89 (0.80-0.998), 0.90 (0.83-0.97), 0.86 (0.80-0.94), 0.87 (0.77-0.98), and 1.04 (0.94-1.16), respectively. The trend for lower odds of symptoms of neurodevelopmental delays across quintiles of higher maternal fish intake were significant for fine motor, problem-solving, and personal-social but not communication or gross motor.

Conclusions

Fish consumption during pregnancy may be associated with a reduced risk of neurodevelopmental delay in 3-year-olds, particularly in the fine motor, problem-solving, and personal-social domains. Continued investigation after the age of 3 could further clarify the association.

Are children and dogs best friends? A scoping review to explore the positive and negative effects of child-dog interactions

Personal wellbeing is greatly influenced by our childhood and adolescence, and the relationships formed during those phases of our development. The human-dog bond represents a significant relationship that started thousands of years ago. There is a higher prevalence of dog ownership around the world, especially in households including children. This has resulted in a growing number of researchers studying our interactions with dogs and an expanding evidence base from the exploration of child-dog interactions. We review the potential effects of child-dog interactions on the physical, mental, and social wellbeing of both species. A search of the SCOPUS database identified documents published between January 1980 and April 2022. Filtering for key inclusion criteria, duplicate removals, and inspecting the references of these documents for additional sources, we reviewed a total of 393 documents, 88% of which were scientific articles. We were able to define the numerous ways in which children and dogs interact, be it neutral (e.g., sharing a common area), positive (e.g., petting), or negative (e.g., biting). Then, we found evidence for an association between childhood interaction with dogs and an array of benefits such as increased physical activities, a reduction of stress, and the development of empathy. Nonetheless, several detrimental outcomes have also been identified for both humans and dogs. Children are the most at-risk population regarding dog bites and dog-borne zoonoses, which may lead to injuries/illness, a subsequent fear of dogs, or even death. Moreover, pet bereavement is generally inevitable when living with a canine companion and should not be trivialized. With a canine focus, children sometimes take part in caretaking behaviors toward them, such as feeding or going for walks. These represent opportunities for dogs to relieve themselves outside, but also to exercise and socialize. By contrast, a lack of physical activity can lead to the onset of obesity in both dogs and children. Dogs may present greater levels of stress when in the presence of children. Finally, the welfare of assistance, therapy, and free-roaming dogs who may interact with children remains underexplored. Overall, it appears that the benefits of child-dog interactions outweigh the risks for children but not for dogs; determination of the effects on both species, positive as well as negative, still requires further development. We call for longitudinal studies and cross-cultural research in the future to better understand the impact of child-dog interactions. Our review is important for people in and outside of the scientific community, to pediatricians, veterinarians, and current or future dog owners seeking to extend their knowledge, and to inform future research of scientists studying dogs and human-animal interactions.

Impact of pet dog or cat exposure during childhood on mental illness during adolescence: a cohort study

BACKGROUND

In our prior study of 643 children, ages 4-11 years, children with pet dogs had lower anxiety scores than children without pet dogs. This follow-up study examines whether exposure to pet dogs or cats during childhood reduces the risk of adolescent mental health (MH) disorders.

METHODS

Using a retrospective cohort study design, we merged our prior study database with electronic medical record (EMR) data to create an analytic database. Common MH diagnoses (anxiety, depression, ADHD) occurring from the time of prior study enrollment to 10/27/21 were identified using ICD-9 and ICD-10 codes. We used proportional hazards regression to compare time to MH diagnoses, between youths with and without pets. From 4/1/20 to 10/27/21, parents and youth in the prior study were interviewed about the amount of time the youth was exposed to a pet and how attached s/he was to the pet. Exposure included having a pet dog at baseline, cumulative exposure to a pet dog or cat during follow-up, and level of pet attachment. The main outcomes were anxiety diagnosis, any MH diagnosis, and MH diagnosis associated with a psychotropic prescription.

RESULTS

EMR review identified 571 youths with mean age of 14 years (range 11-19), 53% were male, 58% had a pet dog at baseline. During follow-up (mean of 7.8 years), 191 children received a MH diagnosis: 99 were diagnosed with anxiety (52%), 61 with ADHD (32%), 21 with depression (11%), 10 with combined MH diagnoses (5%). After adjusting for significant confounders, having a pet dog at baseline was associated with lower risk of any MH diagnosis (HR = 0.74, p = .04) but not for anxiety or MH diagnosis with a psychotropic prescription. Among the 241 (42%) youths contacted for follow-up, parent-reported cumulative exposure to pet dogs was borderline negatively associated with occurrence of any MH diagnosis (HR = 0.74, p = .06). Cumulative exposure to the most attached pet (dog or cat) was negatively associated with anxiety diagnosis (HR = 0.57, p = .006) and any MH diagnosis (HR = 0.64, p = .013).

CONCLUSION

Cumulative exposure to a highly attached pet dog or cat is associated with reduced risk of adolescent MH disorders.

The relationship between evaluation of shared decision-making by pet owners and veterinarians and satisfaction with veterinary consultations

Background

Communication skills are a necessary competency in veterinary medicine, and shared decision-making (SDM) between practitioners and patients is becoming increasingly important in veterinary practice as in human medicine. There are few studies that have quantitatively measured SDM in veterinary health care, and the relationship between SDM and consultation satisfaction is unknown. The purpose of this study was to investigate the status of SDM implementation in veterinary hospitals and the relationship between SDM implementation and consultation satisfaction among pet owners. We conducted a cross-sectional study using self-administered questionnaires among pet owners and veterinarians. In total, 77 pet owners who visited a veterinary clinic and 14 veterinarians at the clinics participated in this study. After a veterinary clinic visit, owners were asked to rate their decision-making preferences using the Shared Decision Making Questionnaire for patients (SDM-Q-9) adapted for veterinary medicine, as well as their satisfaction with the consultation. The corresponding veterinarians were asked to complete the veterinary version of the survey (SDM-Q-Doc).

Results

Most pet owners (64.9%) preferred SDM in veterinary consultations. Cronbach's alpha coefficient of 0.84 for the veterinary SDM-Q-9 and 0.89 for the veterinary SDM-Q-Doc both confirmed high reliability. The Spearman's correlation coefficient between the SDM-Q-9 and consultation satisfaction was 0.526 (p < 0.001), which was significant. The SDM-Q-Doc was not significantly correlated with either the SDM-Q-9 or pet owner consultation satisfaction. We conducted a sensitivity analysis of correlations among veterinarians; responses on the SDM-Q-Doc to examine the association between the SDM-Q-Doc and SDM-Q-9 and owner satisfaction; the results remained the same and no association was found.

Conclusions

Our findings suggest that evaluation of SDM among pet owners was associated with their satisfaction with veterinary consultation. Veterinarians may be able to improve the satisfaction level of pet owners by adopting a consultation method that increases SDM. We did not consider the content of veterinary care or the number of visits to the veterinary clinic; future studies should be conducted to confirm the validity of our results.

Repeated maternal non-responsiveness to baby's crying during postpartum and infant neuropsychological development: The Japan Environment and Children's Study

BACKGROUND

Longitudinal adverse effects of neglect-related behaviors during postpartum, especially repeated maternal non-responsiveness to the crying baby on their neuropsychological developmental trajectory, have not been fully clarified.

OBJECTIVE

This study aimed to examine the association between postpartum maternal neglect-related behaviors and infant neuropsychological outcomes using the Japan Environment and Children's Study (JECS).

PARTICIPANTS AND SETTING

JECS data on 100,286 mother-child pairs were analyzed. Explanatory variables were "frequency of leaving the baby alone at home" (i.e., leaving the baby alone at home) and "frequency of ignoring the baby when he or she cries" (i.e., ignoring the crying baby) at one month postpartum. The outcomes were measured using the Japanese version of the Ages & Stages Questionnaires-Third Edition (J-ASQ-3).

METHODS

After multiple imputations, logistic regression analysis was performed to evaluate the association between neglect-related behaviors and the J-ASQ-3 domains at each age.

RESULTS

The "sometimes or more" group of "ignoring the crying baby" from six months to three years reported relatively consistent significant associations with developmental delay in communication (maximum adjusted odds ratio [aOR]: 1.456, 95% confidence interval [CI]: 1.261-1.682), gross motor (maximum aOR: 1.279, 95% CI: 1.159-1.411), fine motor (maximum aOR: 1.274, 95% CI: 1.113-1.457), problem-solving (maximum aOR: 1.178, 95% CI: 1.104-1.256), and personal-social domains (maximum aOR: 1.326, 95% CI: 1.255-1.402). The adverse effects of "leaving the baby alone at home" disappeared in many domains by the age of one.

CONCLUSIONS

Repeated maternal non-responsiveness to baby's crying during postpartum may suppress multiple neuropsychological development during early childhood.

Prospective association of air purifier use during pregnancy with the neurodevelopment of toddlers in the Japan Environment and Children's Study

We examined the association between maternal air purifier use during pregnancy and neurodevelopmental delay in toddlers by analysing data from 82,457 mother-toddler pairs. Air purifier use was measured using a simple yes/no question. Developmental delays at 1.5, 2.0, 2.5, and 3.0 years were assessed using the Ages and Stages Questionnaire, Third Edition. Generalized additive mixed model analysis with 21 covariates revealed that air purifier use was associated with lower prevalence of developmental delay in all five areas—communication, gross motor, fine motor, problem solving, and personal-social—at all four time points (adjusted risk ratios ranged from 0.827 to 0.927, and only one 95% confidence interval crossed the reference). These findings suggest a negative association between air purifier use during pregnancy and neurodevelopmental delay in toddlers.

Trial registration: UMIN000030786 (15/01/2018).

Serum 25-Hydroxyvitamin D Concentrations and Atopic Dermatitis in Early Childhood: Findings from the Japan Environment and Children's Study

Vitamin D (VitD) may affect immune system modulation and result in the development of atopic dermatitis (AD). However, published findings have remained controversial. We investigated the association between early-life 25-hydroxyvitamin D (25(OH)D) levels and AD risk at childhood with a birth cohort. The data were obtained from “the Japan Environment and Children’s Study (JECS)” and “the Sub-Cohort study of JECS” performed with children aged 2 years. “Liquid chromatography-tandem mass spectrometry” was used to measure VitD. The information on AD was obtained from parents’ answers to a questionnaire when their children were aged 3 years. In order to explain the seasonal effects on VitD levels, a deseasonalized continuous variable was further calculated. The logistic regression models were fitted to evaluate the effect of VitD on childhood AD. The study included 4378 children with complete data on VitD and AD. The results from models indicated that low VitD at 2 years was not a risk factor for the development of AD at 3 years, after adjusting for potential confounders. Moreover, there was no U-shape relationship between deseasonalized VitD and childhood AD. Overall, early-life 25(OH)D levels were not link to the increased risk of developing childhood AD.

Association between Early Life Child Development and Family Dog Ownership: A Prospective Birth Cohort Study of the Japan Environment and Children's Study

Pets may play a role in the social-emotional development of children. In particular, some studies have suggested that family dog ownership is associated with better health outcomes. To date, no study has assessed child development in association with dog ownership of different time points. The purpose of the current study was primary to investigate whether “ever” family dog ownership was associated with early child development, and secondary to further examine whether associations between family dog ownership and early child development differ among family dog ownership of status, including “past only”, “current only”, and “always” groups, using the data of family dog ownership obtained at multiple time points. Associations between family dog ownership and infant development at 3 years of age were examined using data from a nationwide prospective birth cohort study, the Japan Environment and Children’s Study (n = 78,941). “Ever” family dog ownership was categorized to “past only”, “current only”, and “always”. We observed that children with “ever” family dog ownership showed a significantly decreased risk of developmental delay in the communication (odds ratio [OR] = 0.87; 95% confidence interval [CI]: 0.78, 0.96), gross motor (OR = 0.83; 95% CI: 0.76, 0.92), problem-solving (OR = 0.89; 95% CI: 0.83, 0.96) and personal-social (OR = 0.86; 95% CI: 0.72, 0.92) domains compared to children with “never” family dog ownership. Furthermore, a significantly decreased risk of developmental delay in gross motor function was observed in association with living with dogs in the “past only” (OR = 0.83; 95% CI: 0.73, 0.95) and “always” (OR = 0.86; 95% CI: 0.75, 0.98). In addition, a decreased risk of developmental delay in the problem-solving domain was associated with “past” family dog ownership (OR = 0.87; 95% CI: 0.79, 0.97) and in the personal-social domain was associated with “always” family dog ownership (OR = 0.81; 95% CI = 0.68, 0.95). Given the possible positive association between early life child development and family dog ownership, living with dogs may be an important factor to be considered when assessing child development.

House Dust Avoidance during Pregnancy and Subsequent Infant Development: The Japan Environment and Children's Study

House dust, well known for causing allergy, contains chemicals that are harmful to fetal neurodevelopment. However, whether countermeasures for house dust allergy, such as frequent use of vacuum cleaners, frequent airing of futons, and the usage of anti-mite covers during pregnancy, are related to subsequent reduced risk of infant developmental delay remains unknown. Therefore, we examined this association by analyzing 81,106 mother-infant pairs who participated in a nationwide birth cohort in Japan. Infant developmental delays at 6 and 12 months postpartum were assessed using the Ages and Stages Questionnaire, Third Edition. A generalized linear model analysis was used to derive adjusted odds ratios (AORs) with the lowest care frequency as reference, while controlling 22 covariates. Our analysis showed that the above-mentioned cleaning measures were overall associated with a reduced risk of developmental delays, both at 6 and 12 months postpartum (AOR varied from 0.73 to 0.95, median: 0.84). Additionally, risks tended to decrease with an increase in the cleaning frequency. In conclusion, a negative dose-response association existed between these measures during pregnancy and infant developmental delay. Our results identify a potential role of frequent vacuum cleaning, airing bedding, and usage of anti-mite bedding covers in promoting intact infant development.

Factors influencing exclusive breastfeeding rates until 6 months postpartum: the Japan Environment and Children's Study

This research aimed to examine the efficacy of the early initiation of breastfeeding within 1 h of birth, early skin-to-skin contact, and rooming-in for the continuation of exclusive breastfeeding until 6 months postpartum. The research used data from the Japan Environment and Children's Study (JECS), a nationwide government-funded birth cohort study. A total of 80,491 mothers in Japan between January 2011 and March 2014 who succeeded or failed to exclusively breastfeed to 6 months were surveyed in JECS. Multiple logistic regression model was used to analyse the data. The percentage of mothers who succeeded in exclusively breastfeeding to 6 months is 37.4%. Adjusted odds ratios were analysed for all 35 variables. Early initiation of breastfeeding (adjusted odds ratio [AOR]: 1.455 [1.401-1.512]), early skin-to-skin contact (AOR: 1.233 [1.165-1.304]), and rooming-in (AOR: 1.567 [1.454-1.690]) affected continuation of exclusive breastfeeding. Regional social capital (AOR: 1.133 [1.061-1.210]) was also discovered to support the continuation of breastfeeding. In contrast, the most influential inhibiting factors were starting childcare (AOR: 0.126 [0.113-0.141]), smoking during pregnancy (AOR: 0.557 [0.496-0.627]), and obese body type during early pregnancy (AOR: 0.667 [0.627-0.710]).

Population-Based Birth Cohort Studies in Epidemiology

Birth cohort studies are the most appropriate type of design to determine the causal relationship between potential risk factors during the prenatal or postnatal period and the health status of the newborn up to childhood and potentially adulthood. To date, there has been a growth in interest regarding observational population-based studies which are performed to provide answers to specific research questions for defined populations, for instance, assessing the exposure to environmental pollutants or drugs on the risk of developing a disease. Birth cohorts based on the recruitment and active follow-up of mothers and children allow the collection of biological material, and specific clinical and genetic information. However, they require a considerable amount of time and resources and, besides being usually of limited size, they are exposed to the risk of the loss of subjects to follow-up, with decreased statistical power and possible selection bias. For these reasons, linking the medical birth register with administrative health records for mothers and babies is increasingly being used in countries with a universal healthcare system, allowing researchers to identify large and unselected populations from birth, and to reconstruct relevant traits and care pathways of mothers and newborns. This Special Issue of the International Journal of Environmental Research and Public Health focuses on the current state of knowledge on perinatal and postnatal exposures and adverse pregnancy, maternal, fetal and neonatal outcomes through population-based birth cohort studies, with a specific focus on real-word data. The 12 accepted articles covered a wide range of themes that can be addressed specifically through birth cohort study design; however, only three were based on real word data with record-linkage to health administrative databases. In particular, two papers have addressed the topic of socioeconomic status considering several indicators both at the individual and contextual level. Two papers focused on inflammatory bowel diseases, both as an outcome of perinatal and antibiotic exposure in early life and as a condition associated with asthma, among children identified in a birth cohort based on a Regional Medical Birth Register. Three articles focused on medication use during pregnancy and its impact on maternal and fetal health. The effect of exposure to prenatal environmental risk factors on perinatal and childhood outcomes has been considered in two papers. Two papers analyzed ad hoc nationwide prospective birth cohorts set in Japan and UK. Finally, we included a systematic review with meta-analysis to evaluate the relation between growth restriction at birth and congenital heart defects. We think that this Special Issue may contribute to enriching the discussion of future challenges, opportunities, strengths and limitations for all research topics that can be investigated using a population-based birth cohort study design.