Association between autistic traits and home nurture environment: A community-based study

Background: Increasing attention has been directed toward understanding the ways in which social environmental factors in�uence children’s behavior, in physical and mental health domains. Autistic traits are continuously distributed in general population and children with autistic traits have great risk of additional mental diseases. However, no literature has demonstrated the relation between autistic traits and home nurture environment. Methods: Caregivers of 408 kindergarten children (68% male) were recruited to complete a series of survey measures in China. The measures used were the Clancy Autistic Behavior Scale and the Home Nurture Environment Scale. Multivariate logistic regression analysis was used to examine the associations. Results: Frequent language/cognition stimulation (aOR 0.520, 95%CI 0.302-0.896), high level of parental warmth (aOR 0.596, 95%CI 0.392-0.905) and high quality of physical living environment (aOR 0.332, 95%CI 0.196-0.561) were the protective factors of autistic traits after controlling the confounding factors. Results were generally not moderated by the child’s gender or birth order. Conclusions: These �ndings highlight the importance of high levels of home nurture environment for autistic traits and indicate that public health programs should focus on guidance of parents for developing more adequate parenting skills and favorable home nurture environment.


Background
Autistic traits are characterized by di culties in interpreting social information, de cits in understanding those feelings of others, lessened desire to interact with others, repetitive and rigid behavior patterns.[1] Extensive evidence demonstrates that autistic traits are continuously distributed in general population.[2,3]Assessing autistic traits in children is crucial because of the potential mental health implications they may have.Several studies have proved that children with a high level of autistic traits has a greater risk of additional mental diseases.[4] Social and communicative de cits characteristic of autistic traits have also been demonstrated to occur at elevated rates among children with other psychiatric conditions including mood disorders [5] , anxiety [6], depression [7], conduct/oppositional de ant disorders [8] and even an early precursor of psychotic experiences.[9] In addition to this, Children with autistic traits have social interaction needs for peer problems [10][11][12] as well as higher risk for interpersonal victimization.[13] In recent years, increasing attention has been directed toward understanding the ways in which social environmental factors in uence children's behavior, in physical and mental health domains.[14,15] Parental guidance and family support are critical to the development of children's psychological quality and health-related behaviors.[14,16] Children living in chaotic households (e.g., lack of organization, confusing and unpredictable schedules and loud noise) reveal more behavioral problems.[17] Thus, to the extent that parents with low quality parenting would lead to poor nurture environment, the child may also exhibit poorer mental and physical health.[18] However, most studies are limited by a focus on speci c domains of autistic traits (e.g., theory of mind) or by the limited areas of parenting styles.On the best of our knowledge, as yet, no literature has demonstrated the relation between autistic traits and home nurture environment.In China, there are concerns that the concurrence of the only-child policy and the tradition of respect for elders, lial piety and obedience would result in increased stress of children, which may lead to behavior problems.[19,20] Thus, it has practical signi cance to carry out relevant research.Given this, the aim of this study was to investigate the association between children aged 3 to 6 years with autistic traits and their home nurture environmental factors in China.

Participants and data collection
We identi ed the positive screening result of Clancy Autism Behavior Scale [21] as the speci c outcome.
We run the test on the 2600 children age 3-6 years from 6 kindergartens in Taicang District, Suzhou from May to June, 2019.If the result turned to positive, then we consider the child was with autistic trait.Then we used Home Nurture Environment Scale [22] to evaluate the circumstance of the home nurture environment.Meanwhile, demographic data was collected including gender, parental education level, birth order, separation period with mother and the primary caregiver.Children with pre mental disease and acute medical illness were excluded from the study.The primary caregiver of children gave informed consent prior to entry into the study rst and then ful lled the questionnaires.The study adhered to the Declaration of Helsinki and ethics approval was obtained from the Institutional Review Board of Soochow University.Ultimately, a total of 204 children who satis ed the inclusion and exclusion criteria formed the screening positive group.(Figure 1 shows) In consideration of gender as a proven risk factor [23] as well as birth year and birth order as clinical confounding factors, the 204 children was matched to controls on the three factors mentioned above.The controls were normally developing children from kindergartens aged from 3-6years in Taicang District, Suzhou.For data quality control, 5% of the questionnaires were randomly selected and were rechecked, and on average, these showed 97% (73/75) consistency with previously answers.

Autistic traits
Autistic traits were measured with the Clancy Autism Behavior Scale (CABS) [21].It is a validated tool for assessing the risk of autistic traits in screening toddlers aged between 2 to 6 years which widely used in mainland China.[24,25] It contains 14 items with each item rating three frequency levels, including "Never" (score of 0) "Occasionally" (score of 1) and "Often" (score of 2).Scores on the CABS are usually divided into three groups according to cut-off points of 14 and 21.For the reason that the scale is consisted of 14 kinds of typical autistic behaviors, using this scale to identify autistic traits is reasonable.
If a child scores equal to or higher than 14, the child is considered as a case with autistic traits.One previous study reported a sensitivity of 88% and speci city of 82% about the performance of CABS.[26]

Home Nurture Environment
The 3~6 Years Child Home Nurture Environment Scale [22] is designed based on Chinese culture background, which consist of 53 items in order to measure diverse variables associated with parenting behaviors and living environment.Each item is divided by 5 frequency rates (hardly ever, seldom, occasionally, frequently and normally) to 5 points (1, 2, 3, 4 and 5).The total rewards will be calculated by these points and will rank to 3 levels (good, average and unsatisfactory).The good level is higher than 85%, the average level is de ned by 15%-85% and the percentage below 15 is unsatisfactory.The scale included six factors: language/cognition stimulation, parental warmth, social adaptation/self care, variety of actives and games, neglect/intervention/punishment and physical living environment.It should be completed by caregivers.The reliability coe cients of the scale indicated by split-half correlation (0.871) and Cronbach alpha (0.930) are satisfactorily high.

Statistical analysis
Initial unadjusted analyses were performed for all demographic and nurture environmental variables to identify those signi cantly associated with autistic traits.Categorical variables were presented as frequencies and percentages and conducted by chi-square test.Continuous variables were analyzed by independent t-test and presented as mean and standard deviation.Variables that were clinically relevant or that showed a univariate relationship with outcome were entered into multivariate logistic regression model.Multivariate logistic regression model with adjusted odds ratio was performed to predict nurture environmental factors associated with autistic traits.P-values were calculated to three decimal places and P<0.05 was the criterion for signi cance.All analysis was performed using SPSS, Version22.(SPSS Inc, Chicago, USA)

Results
All of children were 3-6 years old and of Han ethnicity.Among the 204 cases and 204 controls, there were 140 male and 64 female children for a sex ratio of 2.02:1, re ecting the male preponderance for the autistic trait.The mean age of autistic children was 4.65±1.111years, and mean age of normal children was 4.75±1.109years.(t=0.981,P=0.327) Table 1 displays the mean scores of home nurture environment scale for each level.Based on the result, there was no unsatisfactory level among six levels.On multivariate regression analyses(Table 3), adjusting for familial characteristics(birth year, gender, birth order, parental educational level, primary caregiver and separation period) showed frequent language/cognition stimulation(aOR 0.520, 95%CI 0.302-0.896),favorable parental warmth(aOR 0.596, 95%CI 0.392-0.905),pleasant physical living environment(aOR 0.332, 95%CI 0.196-0.561)were associated with decreased odds of autistic traits.Adjusted for: birth year, gender, birth order, parental educational level, primary caregiver and separation period

Discussion
We have conducted a rigorous community-based cross-sectional study, frequency-matched on gender, birth year and birth order to investigate the home nurture environmental factors for autistic traits in China.
Overall, the results from the study suggested that poor home nurture environment, including insu cient language/cognition stimulation, undesirable parental warmth and poor physical living environment may place preschool children at a great risk for autistic traits.We will discuss each of these ndings in turn and address the implications of these ndings.
We found that frequent language/cognition stimulation, which means the quality of verbal and cognitive information a caregiver provides to a child was signi cantly associated with autistic traits.In other words, children with higher levels of autistic traits reported by caregivers had more di culty on language interaction.The variability in child language in the early years is well-established.[27] Positive characteristics such as high maternal vocabulary level [27] and high socio-economic status[28] have advantageous impact on children's language and cognitive development.One previous research also demonstrated that poorer child language development predicted more autistic traits.[29] It is hypothesized that the identi ed association between autistic traits and language and cognitive stimulation may be explained by two key pathways.Firstly, there is a relationship between early language and later autistic traits, which is comparatively to the interaction with caregivers.[30] Therefore, caregivers did not give children enough response and less opportunities on verbal and cognitive information, children with autistic traits themselves has de ciency on capability for self-explanation and communication, and as a result, the symptom would also be more obvious.Alternatively, it has been reported that the shared genetic in uences of children and caregivers may be responsible for the overlap in linkage signals reported in molecular genetic studies of language skills and autistic traits.[31,32] Caregivers themselves had defect on communication skills, and therefore decrease the stimulation of language at home environment.Although this nding need to be replicated before any rm conclusions can be mad, it raises the possibility that early interventions in terms of language and cognitive skills by caregivers may reduce the occurrence of autistic traits.
Previous research has demonstrated parental warmth an indicator of parents' love and acceptance of the child [33] which was associated with children's better mental health and psychological adjustment, as well as lower levels of child behavior problems.[34] Studies examining warm affect, positive cooperation and communication showed negative associations with conduct problems and high levels of emotional symptoms.[35,36] In our study, we found parental warmth a protective factor for autistic traits.Generally speaking, if a child did not experience consistent warmth from a parent, his own positive emotional responsiveness to the parent might decrease.Likewise, if a parent found that their attempts at warmth were not reciprocated, the frequency of their displays of warmth would also decrease over time.[35] Preschool children with high levels of autistic trait were preceded by early manifested ASD-like problems in infancy and toddlerhood.[37] Thus, favorable parental warmth and considerate care in early childhood are needed in an attempt to diminish further derailment of the child's behavior and development, and to prevent the autistic traits or related externalizing problems.However, it is yet to be established whether interventions targeting particular aspects of parental warmth or other parenting behaviors can be effective in driving more change in children with high levels autistic traits or if such interventions can directly reduce autistic traits, which are both questions we hope to examine in future studies.
The home physical environment not only affects individual child well-being, but also is an important pathway through which socio-economic inequalities create child health and developmental disparities.
Unstable home physical environment has negative effects on children's health and development.
[38] One possible reason proposed for the negative effects of poor physical environments on child behavior problem is through increased exposure to stress.[39,40] Biological changes are likely to occur if the body is exposed to chronic stress (repeated stress response over time), resulting in dysfunction of the neuroendocrine and immune systems.These systems might be particularly sensitive during the formative years of childhood.[41] Dysfunction of children's neuroendocrine, in turn, is associated with cognitive [42] and socio-emotional [38]outcomes.Children with autistic traits have lower neuropsychological performance [43] and impairment in social function.[11,44] And as a result, terrible home physical environment may make their symptoms more apparent.
All of these ndings should be interpreted in the context of several study limitations.First, there are clear limitations with using a tool of this type to measure home nurture environment.It relies on the observation and perceptions of parents, who may not be entirely objective.Second, because we did not assess other emotional or behavioral problems, we could not rule out the possibilities that other comorbid conditions may have contributed to the signi cant associations between autistic trait and home nurture environment reported in this study.In addition, the study was limited to only six schools in one city, with obvious issues of representativeness for the wider population.

Conclusions
In conclusion, ndings revealed that high levels of autistic traits were related to poor home nurture environment.Furthermore, frequent language and cognition stimulation, favorable parental warmth and pleasant home physical environment were the protective factors for autistic traits.Taken together, the current study extends the previous research on potential in uences in terms of parenting which is relevant to autistic traits, and highlights the importance of home nurture environment.Meanwhile, it would indicate that public health programs should also focus on guidance of parents for developing more adequate parenting skills and favorable home nurture environment.

Figure 1 Flow
Figures

Table 1 .
Scores of Home Nurture Environment Scale for each level

Table 2
presents crude odds ratios from univariate analyses.Father completed primary school or below was associated with increased risk for autistic traits.Decreased risks of autistic traits were found in parents as primary caregiver, high level of language/ cognition stimulation, parental warmth and physical living environment and general quality of home nurture environment(P<0.05).However, maternal educational level, separation period longer than 6 months, frequent neglect/intervention/punishment and insu cient opportunities of social adaptation/self care and variety of actives and games were not signi cantly different between case and control groups.

Table 2 .
Distributions, unadjusted OR and 95% CI for demographic and home nurture environmental