An alternative approach for the analyses and interpretation of attachment sort items

Attachment Q‐Sort (AQS) is a tool for quantifying observations about toddler/caregiver relationships. Previous studies have applied factor analysis to the full 90 AQS item set to explore the structure underlying them. Here we explore that structure by applying multidimensional scaling (MDS) to judgements of inter‐item similarity. AQS items are arranged in the MDS solution along three easily interpretable axes: a model that is compatible with but more parsimonious than factor analysis solutions. This geometrical approach suggests ways to modify the AQS—primarily a research tool—to make it more practical for clinical applications. Sets of AQS data are represented and interpreted in the three‐dimensional model as vectors. Summaries at a finer‐grained level are obtained by finding points in the model where variability across datasets is greatest. We report re‐analyses of archival (published) data, and also data collected with streamlined procedures more suitable in the field. Although not reported here, collection and analysis can both be performed online via a website. The general methodology is not restricted to the current application of toddler attachment.     

Time-to-event analysis of fine particle air pollution and preterm birth: results from North Carolina, 2001-2005

Exposure to air pollution during pregnancy has been suggested to be a risk factor for preterm birth; however, epidemiologic evidence remains mixed and limited. The authors examined the association between ambient levels of particulate matter <2.5 μm in aerodynamic diameter (PM(2.5)) and the risk of preterm birth in North Carolina during the period 2001-2005. They estimated the risks of cumulative and lagged average exposures to PM(2.5) during pregnancy via a 2-stage discrete-time survival model. The authors also considered exposure metrics derived from 1) ambient concentrations measured by the Air Quality System (AQS) monitoring network and 2) concentrations predicted by statistically fusing AQS data with process-based numerical model output (the Statistically Fused Air and Deposition Surfaces (FSD) database). Using the AQS measurements, an interquartile-range (1.73 μg/m(3)) increase in cumulative PM(2.5) exposure was associated with a 6.8% (95% posterior interval: 0.5, 13.6) increase in the risk of preterm birth. Using the FSD-predicted levels and accounting for prediction error, the authors also found significant adverse associations between trimester 1, trimester 2, and cumulative PM(2.5) exposure and preterm birth. These findings suggest that exposure to ambient PM(2.5) during pregnancy is associated with increased risk of preterm birth, even in a region characterized by relatively good air quality.     

析因设计重复测量资料的统计分析及SAS程序实例

目的探讨析因设计重复测量资料的统计分析方法。方法通过构造统计模型,并结合实例给出SAS程序来实现析因设计重复测量资料的统计分析。结果给出了一般线性模型和混合线性模型对处理因素和时间因素进行比较的具体做法。结论在数据之间相关性较为复杂时,混合线性模型更加适合于析因设计的重复测量资料的统计分析。     

An analysis of the four food groups using multidimensional scaling

To date, researchers have not tested whether the food groupings represented by various food guides reflect consumers' food classification systems. We undertook this study to explore whether multidimensional scaling (MDS) was a useful technique for examining respondents' perceived similarity among foods representing the Four Food Groups guide. This technique allows us to address the following questions: If individuals are given foods representative of the Four Food Groups, how would they group the foods? And, given the individuals' food groupings, what are the underlying dimensions or criteria on which they grouped the foods? Fifty-one college students rated all possible pairs of 23 foods, representing the Four Food Groups, on similar/dissimilar scales. Using an ALSCAL MDS analysis, we found that respondents grouped foods on 3 dimensions. Although the respondents used dimensions (or criteria) other than the nutrient composition of foods, they grouped the foods in a manner similar to but more complex than the Four Food Groups. The respondents seemed to perceive similarities among foods based on convenience in preparation, health-related properties, and source (animal and plant). Our results indicate that the MDS technique seems to be an appropriate method by which to examine whether the food groupings represented by a food guide reflects consumers' food classification systems.     

幼儿气质量表的应用研究

目的 对W.Fullard等设计的1－3岁幼儿气质量表进行修订,并探讨其应用的适用性。方法 根据量表修订步骤和常模制订方法,在全国六大行政区按整群抽样原则,对3486例幼儿进行了气质测量。结果 修订后的幼儿气质量表较好的信度和效度;幼儿九个气质特征中已有五个出现性别差异。结论 修订后的幼儿气质量表能够反映我国幼儿的气质特点,有较好的科研和临床应用价值。     

The Impact of Toddler Milk Claims on Beliefs and Misperceptions: A Randomized Experiment with Parents of Young Children

BackgroundToddler milk (ie, a nutrient-fortified milk-based drink marketed for children aged 12 to 36 months) has been marketed increasingly in the United States with structure/function claims on product packaging that are potentially misleading.ObjectiveThis study examined how structure/function claims impact parents’ beliefs and perceptions about a toddler milk product.DesignThis was a 3-arm between-subjects randomized experiment.ParticipantsA diverse sample of 2,190 US parents of children aged 1 to 5 years were chosen to take an online survey.InterventionParticipants were randomly assigned to view a toddler milk package with either an unrelated claim (“new and improved,” ie, control condition), a “brain development” claim (ie, “brain” claim), or an “immunity-related” claim (ie, “immunity” claim).Main outcome measuresOutcomes included perceptions, intentions, and beliefs about the toddler milk product.Statistical analyses performedLinear regression for continuous outcomes and logistic regression for dichotomous outcomes.ResultsParents who were exposed to the “brain” claim or the “immunity” claim were more likely to incorrectly believe that the toddler milk was as healthy or healthier than cow’s milk compared with those who saw the control claim (89% for brain claim, 87% for immunity claim, and 79% for control; P < .001 for both comparisons). Parents exposed to either the brain or immunity claim had higher intentions to give the toddler milk to their child, higher perceived product healthfulness, and stronger beliefs that pediatricians would recommend the product compared with parents exposed to the control (all, P < .001).ConclusionsThese findings suggest that structure/function claims on toddler milk packaging may mislead parents and increase the appeal of toddler milk. Our findings support calls for public health policies to regulate marketing on toddler milk packaging.     

Using multidimensional scaling on data from pairs of relatives to explore the dimensionality of categorical multifactorial traits.

An accurate specification of the dimensionality and ordering of categorical multifactorial phenotypes (e.g., smoking status, including heavy, moderate, light, and nonsmokers) is an important prerequisite for the genetic analysis of these traits. Typically, phenotypic dimensionality and ordering are determined by comparing the relative fits of alternative parametric threshold models. Here, a method of analysis is described which addresses the same issue of trait dimensionality but does not require parametric assumptions. Specifically, we detail how nonmetric multi-dimensional scaling (MDS), applied to contingency tables which cross-classify the phenotypes or responses of one relative with another, may be used to explore trait dimensionality. Scaling results from deterministic simulation studies indicate that the latent structure of categorical phenotypes can be recovered with nonmetric MDS. Results from stochastic simulations, however, indicate that the accuracy of recovery, as well as the rejection of models of incorrect dimensionality, are strongly dependent upon sample size and the latent liability correlation between relatives. As an application of the method, the dimensionality of a measure of smoking status in 1,656 pairs of monozygotic twins ascertained through the American Association of Retired Persons is considered. The MDS results indicate that the onset of the smoking habit and the quantity smoked in this aging population represent a unidimensional process. The implication this finding has for subsequent genetic analysis is discussed.     

Robust Inference of Population Structure for Ancestry Prediction and Correction of Stratification in the Presence of Relatedness

Population structure inference with genetic data has been motivated by a variety of applications in population genetics and genetic association studies. Several approaches have been proposed for the identification of genetic ancestry differences in samples where study participants are assumed to be unrelated, including principal components analysis (PCA), multidimensional scaling (MDS), and model‐based methods for proportional ancestry estimation. Many genetic studies, however, include individuals with some degree of relatedness, and existing methods for inferring genetic ancestry fail in related samples. We present a method, PC‐AiR, for robust population structure inference in the presence of known or cryptic relatedness. PC‐AiR utilizes genome‐screen data and an efficient algorithm to identify a diverse subset of unrelated individuals that is representative of all ancestries in the sample. The PC‐AiR method directly performs PCA on the identified ancestry representative subset and then predicts components of variation for all remaining individuals based on genetic similarities. In simulation studies and in applications to real data from Phase III of the HapMap Project, we demonstrate that PC‐AiR provides a substantial improvement over existing approaches for population structure inference in related samples. We also demonstrate significant efficiency gains, where a single axis of variation from PC‐AiR provides better prediction of ancestry in a variety of structure settings than using 10 (or more) components of variation from widely used PCA and MDS approaches. Finally, we illustrate that PC‐AiR can provide improved population stratification correction over existing methods in genetic association studies with population structure and relatedness.     

Teacher Re-creation of Negative Interactions with Toddlers

Fifty two-year olds and fifty three-year olds from low-income families were observed in 10 urban day care centers serving disadvantaged families. Microanalytic chains of child-teacher interactions were recorded and then recoded to represent positive and negative behaviors. Two-year old male toddlers behaved more negatively than two-year old girls or three-year old children. In turn, male toddlers elicited more negative behaviors from their caregivers. Teachers seemed to be controlled by children's behaviors—responding positively to positive behaviors and negatively to negative behaviors. Providers may unwittingly recreate in group care the negative interactions, predictive of poor socioemotional adjustment, that toddlers are already experiencing at home. These data have important implications for mental health toddler workers involved in training teachers in early childhood settings.     

Low-income,African American Adolescent Mothers and Their Toddlers Exhibit Similar Dietary Variety Patterns

ObjectiveTo examine the relationship between maternal and toddler dietary variety.DesignLongitudinal; maternal and toddler dietary data were collected at 13 months; anthropometry was collected at 13 and 24 months.SettingData were collected in homes.Participants109 primiparous, low-income, African American adolescent mothers and toddlers.Main Outcome MeasuresMaternal and toddler dietary variety and toddler obesity at 24 months.AnalysisCorrelations were computed to estimate associations between maternal and toddler dietary variety at 13 months; multiple logistic regression analyses were conducted to estimate associations between maternal and toddler diet and toddler growth.ResultsMaternal and toddler fruit, vegetable, snack, meat, dairy, and soda variety were significantly correlated. There was no association between maternal and toddler dietary variety and obesity at 24 months. Adolescent mothers who purchased groceries consumed more fruits and vegetables and provided more variety for their toddlers than those who relied on others to purchase groceries.Conclusions and ImplicationsAdolescent mothers and toddlers exhibited similar dietary patterns; consuming more sweets and less fruits and vegetables than recommended. Toddlerhood is an optimal time to address healthful dietary patterns and to help adolescent mothers influence grocery purchasing decisions. Goals are to establish healthful dietary patterns and reduce pediatric obesity.     

1~2岁幼儿依恋特征及有关影响因素的探讨

【目的】 了解128名1~2岁幼儿依恋特征及母亲敏感性、气质等基本因素对其影响作用。 【方法】 采用陌生情境试验和现场观察对儿童依恋状况和儿童母亲敏感性进行测评,并由母亲填写家庭一般人口学资料和幼儿气质问卷。 【结果】 128名幼儿中,安全型依恋99人(77.3%),回避型24人(18.8%),抗拒型5人(3.9%),未发现混乱型。不同依恋类型儿童母亲的敏感性得分差异显著;趋避性、心境、持久性、注意分散等气质维度与儿童某些依恋行为呈现明显相关关系。 【结论】 济南市城区幼儿依恋安全型比例较高;母亲敏感性是影响儿童依恋重要因素之一;儿童气质对依恋类型不产生直接影响,但某些气质维度影响儿童特定情景下的依恋行为表现。     

Validation of an instrument to assess toddler feeding practices of Latino mothers

This paper describes qualitative and quantitative aspects of testing a 34-item Toddler-Feeding Questionnaire (TFQ), designed for use in Latino families, and the associations between feeding practices and toddler dietary outcomes. Qualitative methods included review by an expert panel for content validity and cognitive testing of the tool to assess face validity. Quantitative analyses included use of exploratory factor analysis for construct validity; Pearson's correlations for test-retest reliability; Cronbach's alpha (α) for internal reliability; and multivariate regression for investigating relationships between feeding practices and toddler diet and anthropometry. Interviews were conducted using a convenience sample of 94 Latino mother and toddler dyads obtained largely through the Supplemental Nutrition Program for Women, Infants and Children (WIC). Data collection included household characteristics, self-reported early-infant feeding practices, the toddler's dietary intake, and anthropometric measurements. Factor analysis suggests the TFQ contains three subscales: indulgent; authoritative; and environmental influences. The TFQ demonstrated acceptable reliability for most measures. As hypothesized, indulgent practices in Latino toddlers were associated with increased energy consumption and higher intakes of total fat, saturated fat, and sweetened beverages. This tool may be useful in future research exploring the relationship of toddler feeding practices to nutritional outcomes in Latino families.     

父母教养方式量表（EMBU）在青少年中的因素结构研究

目的 探索父母教养方式量表（EMBU）在青少年样本中的因素结构。 方法 用岳冬梅版父母教养方式量表对1 077名青少年进行调查。50% 样本用SPSS进行探索性因素分析,另50%用AMOS进行验证性因素分析。 结果 岳冬梅定义的因素结构在青少年样本中较不稳定;通过探索性因素分析得出的新量表,由情感温暖、惩罚和过分保护3个因子共19个条目组成,父亲版和母亲版累计解释方差分别为50.8%和51.4%;验证性因素显示与调查数据适配性好,各因子Cronbach α系数0.65～0.86,各因子与总量表的相关系数为0.34～0.65,表明量表具有良好的信度和效度。结论 修订的新量表有较好信度和效度,可在青少年中使用。     

城市1～2岁幼儿依恋问卷及其判别函数的建立

目的 编制儿童依恋行为问卷并建立其判别函数, 为评价1~2岁幼儿依恋行为测评提供工具。方法 查阅有关文献和专家访谈, 以儿童依恋行为分类卡(Attachment Q-set, AQS)为基础构建儿童依恋条目库, 经预测试形成“依恋初始问卷”。随机抽取8市城区612名1～2岁儿童进行初始问卷测试, 经6次探索性因素分析, 删除CR值达不到显著水平、与总分相关系数<0.30的条目以及项目负荷量<0.4的条目, 最后形成《1～2岁幼儿依恋问卷》, 然后进行信度检验和效度检验。通过对济南市城区128名幼儿SSP分析结果和依恋问卷数据进行判别分析, 形成依恋类型的判别函数。结果 《1~2岁幼儿依恋问卷》含有8个因子, 36个条目。同质信度克伦巴赫系数为0.77, 分半信度为0.74, 重测信度为0.56;内容效度和结构效度均达到良好水平。与SSP相比, 判别函数对A型、C型判定符合度为100%, 对B型判定符合度98%。SSP分型和依恋问卷判别分型之间差异无统计学意义(χ²=0.13, P=0.94)。结论 依恋问卷信度、效度以及判别函数区分度良好, 达到心理测量学的标准, 可以用作1～2岁幼儿依恋行为的测评工具。     

Study on the relationship between toddler temperament and development (first report)--the correlation among toddler temperament, maternal perception and rearing environment]

The purpose of this study is to clarify how a child's temperament and maternal perception influences the rearing environment. As the conceptual framework, we used A.J. Sameroff's transactional model and Miyake's conceptual model of mother and child. The following process was hypothesized: toddler temperament influences maternal perception, which in turn influences rearing environment under which children are developing. Questionnaires concerning toddler temperament, maternal perception and rearing environment were sent to mothers whose children were scheduled to receive 1 year and 6 months child health examinations, and results from 306 mothers and children who answered the questionnaires were analyzed. The results were as follows: (1) Child temperament showed a tendency to accord with maternal perception of how easy it is to handle him/her. (2) Maternal perception was related to rearing environment. (3) Temperamental characteristics were related to rearing environment. (4) While the influence of child temperament and maternal perception on the rearing environment was not shown to be strong, the hypothesized process of this study was supported to a certain degree. From these results, it appears that it is important to pay attention to a child's temperament as a contributing factor in the health practice of mother and child.     

Extended mixture factor analysis model with covariates for mixed binary and continuous responses

Finite mixture factor analysis provides a parsimonious model to explore latent group structures of high-dimensional data. In this modeling framework, we can explore latent structures for continuous responses. However, dichotomous items are often used to define latent domains in practice. This paper proposes an extended finite mixture factor analysis model with covariates to model mixed continuous and binary responses. We use a Monte Carlo expectation-maximization (MCEM) algorithm to estimate the model. In the E step, closed-form solutions are not available for the conditional expectation of complete data log likelihood, so it is approximated by sample means, which are in turn generated by the Gibbs sampler from the joint conditional distribution of latent variables. To monitor the convergence of the MCEM algorithm, we use bridge sampling to calculate the log likelihood ratio of two successive iterations. We adopt a diagnostic plot of the log likelihood ratio against iterations for monitoring the convergence of the MCEM algorithm. We compare different models based on BIC, in which we approximate the observed data log likelihood by using a Monte Carlo method. We investigate the computational properties of the MCEM algorithm by simulation studies. We use a real data example to illustrate the practical usefulness of the model. Finally, we discuss limitations and possible extensions.     

Sweetened Food Purchases and Indulgent Feeding Are Associated With Increased Toddler Anthropometry

ObjectiveTo explore the role of feeding practices and food purchases in toddler dietary intake and anthropometry.MethodsA convenience sample of Latino mother and toddler pairs were interviewed at baseline and at 6-month follow-up. Data on feeding practices, toddler dietary intake, anthropometry, and food purchases were collected using the Toddler-Feeding Questionnaire; 24-hour recalls; measurements of weight, height, and/or length; and food purchase receipts.ResultsIndulgent feeding scores and high intake of sweetened beverage were associated with a 0.52 increase (P = .03) and 0.46 increase in toddler weight-for-height z-score (P = .05), respectively. Households with 10 percentage points of more sweetened food and beverage expenditures were associated with increases in weight indicator z-scores.Conclusions and ImplicationsIndulgent feeding, high intake, and purchase of sweetened beverage are associated with weight gain in Latino toddlers. Programs should target food purchasing decisions and provide concrete guidance for the division of responsibility around feeding.     

早期教育对婴幼儿发育影响的效果评价

目的：探讨早期教育对婴幼儿智能发育的影响。方法：选择109名正常健康儿童作为训练组，随机抽取117名正常儿童作为对照组。受训练组每周集中训练一次，两组儿童在研究期间每三个月使用Gesell进行一次发育评价。结果：受训练组儿童各能区的发育商均高于对照组，差异有显著性（P＜0．05）；进行自身对照，受训练儿童发育商有显著性提高（P＜0．05）。结论：早期教育对婴幼儿智能发育有明显的促进作用。     

混合模型在临床试验重复测量资料中的应用

目的探讨临床试验重复测量资料的统计分析方法。方法通过实例说明并比较各种固定效应模型和混合模型的优缺点。结果临床试验研究资料常为重复测量资料,比较各处理组的测量值差别是否有显著性,可以采用传统的统计方法如t检验、方差分析和协方差分析等;也可以采用混合模型对整个研究过程中所有时点的测量值进行分析。结论由于在重复测量资料中,同一受试者的不同观测值之间具有相关性特点,故对其指定协方差结构尤其重要。Mixed过程提供了丰富的协方差结构,可以充分利用重复测量资料的信息,又能处理缺失值,是重复测量资料最优的统计分析方法。