Wieke de Vente

Multiple imputation of missing values was not necessary before performing a longitudinal mixed-model analysis

BACKGROUND AND OBJECTIVES As a result of the development of sophisticated techniques, such as multiple imputation, the interest in handling missing data in longitudinal studies has increased enormously in past years. Within the field of longitudinal data analysis, there is a current debate on whether it is necessary to use multiple imputations before performing a mixed-model analysis to analyze the longitudinal data. In the current study this necessity is evaluated. STUDY DESIGN AND SETTING The results of mixed-model analyses with and without multiple imputation were compared with each other. Four data sets with missing values were created-one data set with missing completely at random, two data sets with missing at random, and one data set with missing not at random). In all data sets, the relationship between a continuous outcome variable and two different covariates were analyzed: a time-independent dichotomous covariate and a time-dependent continuous covariate. RESULTS Although for all types of missing data, the results of the mixed-model analysis with or without multiple imputations were slightly different, they were not in favor of one of the two approaches. In addition, repeating the multiple imputations 100 times showed that the results of the mixed-model analysis with multiple imputation were quite unstable. CONCLUSION It is not necessary to handle missing data using multiple imputations before performing a mixed-model analysis on longitudinal data.

The analysis of randomised controlled trial data with more than one follow-up measurement. A comparison between different approaches

When more than one follow-up measurement is analysed in a randomized controlled trial, there is no consensus how to analyse the overall intervention effect in a proper way. Mostly, longitudinal analysis of covariance is used, because with this method a correction is made for possible regression to the mean. However, in this paper it is shown that this method (mostly) leads to an overestimation of the intervention effect. A possible solution is the use of autoregression, although this does not seem to be the best solution, because it leads to an overcorrection. Due to these flaws, in this paper a new approach is introduced in which a correction for the baseline value is made for the first follow-up, but no correction is made for the remaining follow-up measurements.

Bidirectional Associations Between Coparenting Relations and Family Member Anxiety: A Review and Conceptual Model

Research into anxiety has largely ignored the dynamics of family systems in anxiety development. Coparenting refers to the quality of coordination between individuals responsible for the upbringing of children and links different subsystems within the family, such as the child, the marital relationship, and the parents. This review discusses the potential mechanisms and empirical findings regarding the bidirectional relations of parent and child anxiety with coparenting. The majority of studies point to bidirectional associations between greater coparenting difficulties and higher levels of anxiety. For example, the few available studies suggest that paternal and perhaps maternal anxiety is linked to lower coparental support. Also, research supports the existence of inverse links between coparenting quality and child anxiety. A child’s reactive temperament appears to have adverse effects on particularly coparenting of fathers. A conceptual model is proposed that integrates the role of parental and child anxiety, parenting, and coparenting, to guide future research and the development of clinical interventions. Future research should distinguish between fathers’ and mothers’ coparenting behaviors, include parental anxiety, and investigate the coparental relationship longitudinally. Clinicians should be aware of the reciprocal relations between child anxiety and coparenting quality, and families presenting for treatment who report child (or parent) anxiety should be assessed for difficulties in coparenting. Clinical approaches to bolster coparenting quality are called for.

Burnout is associated with reduced parasympathetic activity and reduced HPA axis responsiveness, predominantly in males

There is mounting evidence that burnout is a risk factor for cardiovascular disease (CVD). Stress-related dysregulation of the sympathetic and parasympathetic system and the hypothalamic pituitary adrenal (HPA) axis may explain the enhanced risk for CVD. To test this hypothesis, 55 patients (34 males and 21 females) with burnout on sickness absence and 40 healthy participants (16 males and 24 females) were exposed to a psychosocial stressor consisting of mental arithmetic and public speech. Physiological variables (i.e., blood pressure, heart rate, cardiac output, vascular resistance, cortisol, and alpha-amylase) were measured. Basal levels, reactivity, and recovery were compared between groups. In male patients, baseline systolic blood pressure was higher, whereas basal alpha-amylase and cortisol reactivity were lower than in healthy males. In female patients, a tendency for lower basal cortisol was found as compared to healthy females. Furthermore, reduced basal heart rate variability and a trend for elevated basal cardiac output were observed in both male and female patients. Burnout is characterised by dysregulation of the sympathetic and parasympathetic system and the HPA axis, which was more pronounced in males than in females. This study further supports burnout as being a risk factor for CVD through dysregulation of the sympathetic and parasympathetic system and the HPA axis.

Mothers’ and fathers’ mind-mindedness influences physiological emotion regulation of infants across the first year of life

Abstract The main aim of this study was to test whether mothers’ (n = 116) and fathers’ (n = 116) mind‐mindedness predicts infants’ physiological emotion regulation (heart rate variability; HRV) across the first year of life. Three hypotheses were examined: (a) parents’ mind‐mindedness at 4 and 12 months predicts infants’ HRV at 12 months over and above infants’ initial HRV levels at 4 months, (b) mothers’ and fathers’ mind‐mindedness independently predict infant HRV, and (c) the effects of mind‐mindedness on infant HRV (partially) operate via parenting behaviour. Infants’ HRV was assessed during rest and a stranger approach. Mind‐mindedness was assessed by calculating the proportions of appropriate and non‐attuned mind‐related comments during free‐play interactions, and parenting quality was observed at 4 and 12 months in the same interactions. Path analyses showed that mothers’ appropriate mind‐related comments at 4 and 12 months predicted higher baseline HRV at 12 months, whereas mothers’ non‐attuned comments predicted lower baseline HRV at 12 months. Similar, but concurrent, relations were found for fathers’ appropriate and non‐attuned mind‐related comments and infant baseline HRV at 12 months. In addition, fathers’ appropriate mind‐related comments showed an indirect association with infant baseline HRV at 12 months via fathers’ parenting quality. With regard to infant HRV reactivity during the stranger approach, mothers’ appropriate mind‐related comments at 4 months and fathers’ non‐attuned mind‐related comments at 12 months predicted a larger HRV decline during the stranger approach at 12 months. Infants’ HRV at 4 months did not predict parents’ later mind‐mindedness. The results indicate that mothers’ and fathers’ appropriate and non‐attuned mind‐related speech uniquely impacts the development of infants’ physiological emotion regulation.

Longitudinal associations between sleep and anxiety during pregnancy, and the moderating effect of resilience, using parallel process latent growth curve models

BACKGROUND For many women, pregnancy-related sleep disturbances and pregnancy-related anxiety change as pregnancy progresses and both are associated with lower maternal quality of life and less favorable birth outcomes. Thus, the interplay between these two problems across pregnancy is of interest. In addition, psychological resilience may explain individual differences in this association, as it may promote coping with both sleep disturbances and anxiety, and thereby reduce their mutual effects. Therefore, the aim of the current study was to examine whether sleep quality and sleep duration, and changes in sleep are associated with the level of and changes in anxiety during pregnancy. Furthermore, the study tested the moderating effect of resilience on these associations. METHODS At gestational weeks 14, 24, and 34, 532 pregnant women from the FinnBrain Birth Cohort Study in Finland filled out questionnaires on general sleep quality, sleep duration and pregnancy-related anxiety; resilience was assessed in week 14. RESULTS Parallel process latent growth curve models showed that shorter initial sleep duration predicted a higher initial level of anxiety, and a higher initial anxiety level predicted a faster shortening of sleep duration. Changes in sleep duration and changes in anxiety over the course of pregnancy were not related. The predicted moderating effect of resilience was not found. CONCLUSIONS The results suggested that pregnant women reporting anxiety problems should also be screened for sleeping problems, and vice versa, because women who experienced one of these pregnancy-related problems were also at risk of experiencing or developing the other problem.

Validation of the Dutch version of the Pregnancy Experience Scale

The Pregnancy Experience Scale - Brief version (PES-Brief) assesses the frequency and intensity of the hassles and uplifts of pregnancy. This study aimed to assess the psychometric properties of the Dutch PES-Brief-Beleving van Zwangerschap Schaal - verkorte versie (BZS-K)-in a sample of healthy Dutch pregnant women. Participants (n=115) completed questionnaires twice during pregnancy, within a three-week interval. Factor analyses resulted in the expected two factors, one positive and one negative. The BZS-K showed sufficient internal consistency (α=.76 for Hassles, .83 for Uplifts) and reproducibility of subscales (Intraclass correlation coefficients (ICC)=.72-.84). Concurrent validity with measures of pregnancy anxiety, general depression, anxiety and stress, and emotional well-being was established. We conclude that the BZS-K is a reliable, valid measure for assessment of womens perceptions of hassles and uplifts of pregnancy.

Parental Expressions of Anxiety and Child Temperament in Toddlerhood Jointly Predict Preschoolers’ Avoidance of Novelty

This study investigated the link between (a) parents’ social trait and state anxiety and (b) children’s fear and avoidance in social referencing situations in a longitudinal design and considered the modulating role of child temperament in these links. Children were confronted with a stranger and a robot, separately with their father and mother at 1 (N = 122), at 2.5 (N = 117), and at 4.5 (N = 111) years of age. Behavioral inhibition (BI) was separately observed at 1 and 2.5 years. Parents’ social anxiety disorder (SAD) severity was assessed via interviews prenatally and at 4.5 years. More expressed anxiety by parents at 4.5 years was not significantly linked to more fear or avoidance at 4.5 years. High BI children were more avoidant at 4.5 years if their parents expressed more anxiety at 2.5 years, and they were more fearful if the parents had more severe forms of lifetime SAD. More severe lifetime forms of SAD were also related to more pronounced increases in child fear and avoidance over time, whereas parents’ expressions of anxiety predicted more pronounced increases in avoidance only from 2.5 to 4.5 years. High BI toddlers of parents with higher state and trait anxiety become more avoidant of novelty as preschoolers, illustrating the importance of considering child temperamental dispositions in the links between child and parent anxiety. Moreover, children of parents with more trait and state anxiety showed more pronounced increases in fear and avoidance over time, highlighting the importance of early interventions targeting parents’ SAD.

Should we use logistic mixed model analysis for the effect estimation in a longitudinal RCT with a dichotomous outcome variable

Background : Within epidemiology both mixed model analysis and Generalised Estimating Equations (GEE analysis) are frequently used to analyse longitudinal RCT data. With a continuous outcome, both methods lead to more or less the same results, but with a dichotomous outcome the results are totally different. The purpose of the present study is to evaluate the performance of a logistic mixed model analysis and a logistic GEE analysis and to give an advice which of the two methods should be used. Methods : Two real life RCT datasets with and without missing data were used to perform this evaluation. Regarding the logistic mixed model analysis also two different estimation procedures were compared to each other. Results : The regression coefficients obtained from the two logistic mixed model analyses were different from each other, but were always higher then the regression coefficients derived from a logistic GEE analysis. Because this also holds for the standard errors, the corresponding p-values were more or less the same. It was further shown that the effect estimates derived from a logistic mixed model analysis were an overestimation of the ‘real’ effect estimates. Conclusions : Although logistic mixed model analysis is widely used for the analysis of longitudinal RCT data, this article shows that logistic mixed model analysis should not be used when one is interested in the magnitude of the regression coefficients (i.e. effect estimates).