The effect of dietary intake on body weight may vary based on individual genetic differences. However, children are rarely used in such investigations. The aim was to identify possible genetic moderation through polygenic scores (PGS) for BMI, of the association between dietary intakes and BMI in children. The study sample included children who were part of a French-Canadian birth-cohort study. BMI data was available on seven occasions between ages 4 and 13 years. FFQ (juice and fruit drinks, sweets and snack foods, meats, and fruits and vegetables) and 24-h dietary recall (proteins, lipids, carbohydrates, total energy) data were available up to 4 years. Linear mixed models were used to account for repeated BMI measurements. The consumption of juice and fruit drinks (in girls), sweets and snack foods, fruits and vegetables, proteins, lipids, carbohydrates and total energy were associated with BMI. Associations with BMI increased with age (kg/m2 per year) for fruits and vegetables (β: −0.03, 95%CI: −0.06;−0.01), lipids (β: 0.11, 95%CI: 0.01;0.22), carbohydrates (β: 0.05, 95%CI: 0.01;0.08), and total energy (β: 0.07, 95%CI: 0.02;0.12), and with higher values of a PGS (kg/m2 per SD) for proteins (β: 0.54, 95%CI: 0.03;1.06), lipids (β: 0.63, 95%CI: 0.12;1.13), and total energy (β: 0.32, 95%CI: 0.06;0.58). Using longitudinal data, we showed that the associations between specific dietary intakes and BMI may vary depending on age and genetic susceptibility in childhood.

Sensory processing sensitivity (SPS) is a trait characterized by heightened responsiveness to external and internal stimuli. Past research suggests individuals high in SPS may exhibit depressive symptoms, possibly due to their highly sensitive nervous system. While the link between SPS and sleep quality remains unexplored, studies have established a strong association between depression and sleep. This study aimed to compare sensitivity groups concerning sleep quality and depression and to evaluate depression’s moderating effects on the SPS–sleep quality relationship. An online survey was administered to 1,122 Spanish participants (female 75.8%, n = 850), with a mean age of 24.5 (standard deviation [SD] = 11.2). Analyses of covariance (ANCOVAs) indicated that the high-sensitivity group experienced more sleep disturbances and severe symptoms of depression, considering gender, age, and monthly incomes as sociodemographic variables. Depression was found to significantly moderate the SPS–sleep quality relationship (F(2, 1116) = 5.717, p = .003), exacerbating the impact of SPS on sleep disturbances. The study findings suggest that highly sensitive people appear to indicate more severe depressive symptoms, as well as sleep quality disturbances, with the influence of gender, age, and monthly income. Also, depression seems to moderate the relationship between SPS and sleep quality, leading to greater sleep disturbances among highly sensitive individuals with severe depressive symptoms.

Callous-unemotional (CU) traits, characterized by lack of empathy, guilt, and deficient affect, are linked to facial emotion recognition (FER) deficits in children. While anxiety is also associated with FER anomalies, these relationships are often examined in isolation despite co-occurrence. This study aims to concurrently investigate unique contributions of CU traits and anxiety on children’s FER patterns. We recruited 107 children aged 6 to 11 from community settings, assessing CU traits through caregiver reports and anxiety via caregiver and child reports. FER performance was evaluated using a computer-based task. Results indicate that CU traits negatively impact overall FER accuracy, particularly when controlling for parent-reported anxiety. CU traits were inversely related to total FER accuracy for children self-reporting high anxiety levels. These findings enhance our understanding of how CU traits and anxiety interact to influence FER deficits, suggesting that interventions targeting CU traits should consider anxiety symptoms as a critical factor in emotional processing challenges among children.

We examined whether obsessive passion and harmonious passion interacted in the prediction of work–family conflict, and the indirect effects of obsessive passion on counterproductive work behaviors as mediated by work–family conflict. We collected data from two samples of employees with jobs in engineering (Sample 1) and administration (Sample 2). Obsessive passion was associated with higher levels of work–family conflict, whereas harmonious passion was negatively related to work–family conflict. Furthermore, the positive effects of obsessive passion on work–family conflict were lower at high levels of harmonious passion. Work–family conflict was also positively related to counterproductive work behaviors (Sample 2). Finally, the indirect effects of obsessive passion on counterproductive work behaviors (Sample 2) were lower at high levels of harmonious passion.

Conditioning on variables affected by treatment can induce post-treatment bias when estimating causal effects. Although this suggests that researchers should measure potential moderators before administering the treatment in an experiment, doing so may also bias causal effect estimation if the covariate measurement primes respondents to react differently to the treatment. This paper formally analyzes this trade-off between post-treatment and priming biases in three experimental designs that vary when moderators are measured: pre-treatment, post-treatment, or a randomized choice between the two. We derive nonparametric bounds for interactions between the treatment and the moderator under each design and show how to use substantive assumptions to narrow these bounds. These bounds allow researchers to assess the sensitivity of their empirical findings to priming and post-treatment bias. We then apply the proposed methodology to a survey experiment on electoral messaging.

The analysis of ‘moderation’, ‘interaction’, ‘mediation’ and ‘longitudinal growth’ is widespread in the human sciences, yet subject to confusion. To clarify these concepts, it is essential to state causal estimands, which requires the specification of counterfactual contrasts for a target population on an appropriate scale. Once causal estimands are defined, we must consider their identification. I employ causal directed acyclic graphs and single world intervention graphs to elucidate identification workflows. I show that when multiple treatments exist, common methods for statistical inference, such as multi-level regressions and statistical structural equation models, cannot typically recover the causal quantities we seek. By properly framing and addressing causal questions of interaction, mediation, and time-varying treatments, we can expose the limitations of popular methods and guide researchers to a clearer understanding of the causal questions that animate our interests.

Essential minerals are cofactors for synthesis of neurotransmitters supporting cognition and mood. An 8-week fully-blind randomised controlled trial of multinutrients for attention-deficit/hyperactivity disorder (ADHD) demonstrated three times as many children (age 6–12) had significantly improved behaviour (‘treatment responders’) on multinutrients (54 %) compared with placebo (18 %). The aim of this secondary study was to evaluate changes in fasted plasma and urinary mineral concentrations following the intervention and their role as mediators and moderators of treatment response. Fourteen essential or trace minerals were measured in plasma and/or urine at baseline and week eight from eighty-six participants (forty-nine multinutrients, thirty-seven placebos). Two-sample t tests/Mann–Whitney U tests compared 8-week change between treatment and placebo groups, which were also evaluated as potential mediators. Baseline levels were evaluated as potential moderators, using logistic regression models with clinical treatment response as the outcome. After 8 weeks, plasma boron, Cr (in females only), Li, Mo, Se and vanadium and urinary iodine, Li and Se increased more with multinutrients than placebo, while plasma phosphorus decreased. These changes did not mediate treatment response. However, baseline urinary Li trended towards moderation: participants with lower baseline urinary Li were more likely to respond to multinutrients (P = 0·058). Additionally, participants with higher baseline Fe were more likely to be treatment responders regardless of the treatment group (P = 0·036.) These results show that multinutrient treatment response among children with ADHD is independent of their baseline plasma mineral levels, while baseline urinary Li levels show potential as a non-invasive biomarker of treatment response requiring further study.