The survey was a sub-project of the demonstration study on the integration and application of key technologies in the nutritional health of rural key populations.Data were obtained from a cross-sectional survey conducted in two counties xiji, haiyuan of ningxia hui autonomous region in southern rural mountains from December 2012 to September 2013.Using multi-stage stratified random cluster sampling methods, we selected six primary schools, 5 junior high schools in XinYing Township, HongYao township, XingLong town, Xi 'An town, ShuTai township form xiji and haiyuan countries . One class from grade 1 to grade 9 was randomly selected from each school. A total of 41 classes were selected for the survey. A total of 2000 questionnaires were distributed, and 1905 valid ones were recovered, with an effective rate of 95.25%, among which 955 (50.1%) hui nationality children were the subjects of this study. The 955 hui nationality students were divided into LBC group (n=383) and non-LBC group (n=572). Inclusion criteria for LBC: who stay in rural areas for more than half a year while their both parents or single parents working outside. They are taken care of by their grandparents, relatives, neighbors, single parent, siblings or themselves. They are aged from 6 to 16 years old. Exclusion criteria: whose both parents or single parent has worked outside for less than 6 months; Having a serious physical or mental illness.
Sociodemographic characteristics: Participants reported their gender, age, nationality, grade, class, family situation, academic performance, caregiver and their education level, parents’ education level and occupation, frequency contact with parents, frequency contact with parents, etc.
Achenbach's Child behavior Checklist (CBCL): Achenbach's Child behavior Checklist was developed by Achenbach, Ph.D, American psychology. Published in 1976, revised for the first time in 1983 , and revised again by Achenbach et al in 1991. There are three versions including parent report version, teacher report version and self-assessment of older children, among which the parent version has the most experience and is the basis of the scale. This scale is applicable to children aged 4 to 16 years and has been widely used in the world. China has also introduced and standardized the scale and formulated the national and hunan norm[37, 38]. In this study, the school-age version checklists included 113 items to identify the children’s behavioral problems, it was mainly used to assess children's various types of behavior for nearly six months by instructing parents or caregivers who were familiar with the children to report the children’s behavioral problems on a 3-point Likert scale (0=not true, 1=somewhat or sometimes true, 2=very true or often true). Male and female students each had eight to nine specific syndromes, including schizoid, depressed, uncommunicative, obsessive-compulsive, somatic complaints, social withdrawal, hyperactivity, aggression and delinquent behavior. Through principal component analysis of the above factors, two dimensions, namely internalizing behavior problem and externalizing behavior problems (EBP), were obtained. We calculated raw scores of specific syndromes, which were used to compare with scores of the norm sample. The higher the score, the more obvious the behavior problem was. In this survey, boys' EBP included hyperactivity, delinquent and aggression; Girls' EBP include hyperactivity, sexual problems, delinquent, aggression and cruel. In this study, Children whose raw scores were above the upper threshold of the norm sample in at least one syndrome were considered to have behavioral disorders. The score of EBP was calculated by adding the the corresponding syndrome scores, in which repeated items were not scored accumulatively.
Egna Minnen av Barndoms Uppfostran（EMBU）：This scale was developed by C. Perris et al., department of psychiatry, Umea university, Sweden, in 1980 to evaluate parenting attitudes and behaviors. This study adopted the Chinese version revised by Dongmei Yue in1993. Cultural differences between Chinese individuals and Western individuals are considered in the revised version, which consists of 66 items and 11 syndromes. Among them, there are 58 items of paternal rearing style, with a total of 6 syndroms, including emotional warmth and understanding, punishment and strictness, over-interference, favoring subjects, refusal and denial and over-protection, There were 57 items of maternal rearing style, with a total of 5 syndroms, including emotional warmth and understanding, over-interference and over-protection, refusal and denial, punishment and strictness and favoring subjects. The test-retest reliability is between 0.58 and 0.82. The split-half reliability is between 0.50 and 0.91, and the internal consistency reliability is between 0.59 and 0.88. Each item is scored according to never =1, occasionally =2, often =3, always =4, and unsuitable =0. The score was determined according to the norm mean score ± standard deviation. Factors < mean score - standard deviation was low score, > mean score + standard deviation was high score, and the rest was medium score.
Eysenck Personality Questionnaire (EPQ) : Personality was assessed using eysenck personality questionnaire for Chinese children which revised by Yao-xian Gong,et al. This version has 88 true-false items and includes four subscales: evaluating neuroticism (N), extroversion-introversion (E), psychoticism (P), and Lie (L) dimensions. Part of the scale is the reverse scoring title. We calculated raw scores of each subscale, and converted into standard T points, standard T < 38.5 for typical low score, 38.5 to 43.3 for tended to low score, 43.3 to 56.7 for the medium type, 56.7 to 61.5 as the tendency to high score, > 61.5 for the typical high score. The Cronbach's alpha was 0.70 for the total scale, 0.76, 0.76, 0.88, and 0.77 for E, P, N, and L, respectively.
Piers Harris Child's self-concept Scale (PHCSS): Children's self-concept Scale (PHCSS) is a self-rating Scale for Children compiled by American psychologists Piers and Harris in 1969 and revised in 1974. It is mainly used to evaluate Children's self- concept. It is composed of 80 items, including 6 subscales of behavioral, intelligence and school status, physical appearance and attributes, anxiety, popularity, happiness and satisfaction. The answer is 1, no 0, part of the question is the reverse score. In 2002,Su linyan et al. introduced, revised and formulated Chinese city norm[39, 41], with good reliability and validity.The factor score was determined according to the norm mean score ± standard deviation, the factors < mean score -standard deviation was low score, the > mean score + standard deviation was high score, and the rest was medium score. The higher the total score or the score of a factor was, the stronger the self-awareness or self-awareness in a certain aspect was.For example, a high "behavior" score indicates that the child is behaving appropriately, and a high "anxiety" score indicates that the child is in good mood and not anxious.The half-reliability of PHCSS scale r = 0.8176 and the Cronhach 'a coefficient was 0.858, which was suitable for the measurement of children's self-concept in China.
We have obtained the approval and support from the local education bureau and the leaders of the investigated schools. The head teacher issue the informed consent for investigation to the WeChat group of parents, and explain the purpose and significance of the investigation in detail to the students and parents/guardians, as well as the way of filling in the questionnaire and the confidential method. Written informed consent signed by the participants and their parents/guardians is brought back to the school. The head teacher then handed over written informed consent from the participants to the researchers. After distributing the questionnaire uniformly in the class, we asked participants to complete the questionnaire within the prescribed time (60 ~ 80 min), and checked and withdrawed the questionnaire on the spot. For grade 1 to grade 3 students, the investigator read each item to the subjects in neutral, non-suggestive language, and asked them to understand and then answer. Achenbach's Child Behavior Checklist (CBCL) should be taken home by the student and submitted to the caregiver for filling out after communication between the head teacher and their parents and shall be taken back within 3 days. For missing students or incomplete answers to the students, we took household supplementary survey. All investigators received training in advance.
Epidata3.0 software was used to establish the database, double input data, and the software SPSS 19.0 for Windows was used for all statistical analyses. A Chi-square test was used for categorical variables and a t test was used for continuous variables. Binary logistic regression was employed to analysis the risk factors of EBP of hui nationality LBC.The value of p takes the probability of two sides, and α takes 0.05 as a test standard.