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Concept: Mediation


Greater fish consumption is associated with improved cognition among children, but the mediating pathways have not been well delineated. Improved sleep could be a candidate mediator of the fish-cognition relationship. This study assesses whether 1) more frequent fish consumption is associated with less sleep disturbances and higher IQ scores in schoolchildren, 2) such relationships are not accounted for by social and economic confounds, and 3) sleep quality mediates the fish-IQ relationship. In this cohort study of 541 Chinese schoolchildren, fish consumption and sleep quality were assessed at age 9-11 years, while IQ was assessed at age 12. Frequent fish consumption was related to both fewer sleep problems and higher IQ scores. A dose-response relationship indicated higher IQ scores in children who always (4.80 points) or sometimes (3.31 points) consumed fish, compared to those who rarely ate fish (all p < 0.05). Sleep quality partially mediated the relationship between fish consumption and verbal, but not performance, IQ. Findings were robust after controlling for multiple sociodemographic covariates. To our knowledge, this is the first study to indicate that frequent fish consumption may help reduce sleep problems (better sleep quality), which may in turn benefit long-term cognitive functioning in children.

Concepts: Sleep, Sleep disorder, Cognition, Mediation, Narcolepsy


To investigate the association between breast feeding and intergenerational social mobility and the possible mediating role of neurological and stress mechanisms.

Concepts: The Association, Mediation, Sunshine pop, Social mobility


Psychosocial stress is a suggested risk for coronary heart disease (CHD). The relationship of stress resilience in adolescence with subsequent CHD risk is underinvestigated, so our objective was to assess this and investigate the possible mediating role of physical fitness.

Concepts: Heart, Middle Ages, Heart disease, Mediation


Several classic studies have concluded that the accuracy of identifying uncontrollable situations depends heavily on depressive mood. Nondepressed participants tend to exhibit an optimistic illusion of control, whereas depressed participants tend to better detect a lack of control. Recently, we suggested that the different activity levels (measured as the probability of responding during a contingency learning task) exhibited by depressed and nondepressed individuals is partly responsible for this effect. The two studies presented in this paper provide further support for this mediational hypothesis, in which mood is the distal cause of the illusion of control operating through activity level, the proximal cause. In Study 1, the probability of responding, P®, was found to be a mediator variable between the depressive symptoms and the judgments of control. In Study 2, we intervened directly on the mediator variable: The P® for both depressed and nondepressed participants was manipulated through instructions. Our results confirm that P® manipulation produced differences in the participants' perceptions of uncontrollability. Importantly, the intervention on the mediator variable cancelled the effect of the distal cause; the participants' judgments of control were no longer mood dependent when the P® was manipulated. This result supports the hypothesis that the so-called depressive realism effect is actually mediated by the probability of responding.

Concepts: Intervention, Bipolar disorder, Mediation, The Mediator


This study investigated relationships between attachment insecurity, maladaptive cognitive schemas, and various types of psychopathological symptoms in a sample of clinically referred adolescents (N = 82). A mediation model was tested in which maladaptive schemas operated as mediators in the relations between indices of attachment quality and conduct, peer, and emotional problems. Results revealed partial support for the hypothesized mediation effect: the schema domain of disconnection/rejection acted as a mediator in the links between insecure attachment and peer problems and emotional problems. Further analysis of these effects revealed that different types of maladaptive schemas were involved in both types of psychopathology. Altogether, findings suggest that treatment of adolescent psychological problems may need to target the improvement of attachment relationships with peers and parents and the correction of underlying cognitive schemas.

Concepts: Psychology, Adolescence, Psychiatry, Attachment theory, Mediation, Peer group, Family therapy, John Bowlby


This systematic literature review appraises critically the mediating variables of stereotype threat. A bibliographic search was conducted across electronic databases between 1995 and 2015. The search identified 45 experiments from 38 articles and 17 unique proposed mediators that were categorized into affective/subjective (n = 6), cognitive (n = 7) and motivational mechanisms (n = 4). Empirical support was accrued for mediators such as anxiety, negative thinking, and mind-wandering, which are suggested to co-opt working memory resources under stereotype threat. Other research points to the assertion that stereotype threatened individuals may be motivated to disconfirm negative stereotypes, which can have a paradoxical effect of hampering performance. However, stereotype threat appears to affect diverse social groups in different ways, with no one mediator providing unequivocal empirical support. Underpinned by the multi-threat framework, the discussion postulates that different forms of stereotype threat may be mediated by distinct mechanisms.

Concepts: Psychology, Cognition, Motivation, Social psychology, Mediation, Stereotype, Stereotypes, Stereotype threat


Coastal and shelf environments support high levels of biodiversity that are vital in mediating ecosystem processes, but they are also subject to noise associated with mounting levels of offshore human activity. This has the potential to alter the way in which species interact with their environment, compromising the mediation of important ecosystem properties. Here, we show that exposure to underwater broadband sound fields that resemble offshore shipping and construction activity can alter sediment-dwelling invertebrate contributions to fluid and particle transport - key processes in mediating benthic nutrient cycling. Despite high levels of intra-specific variability in physiological response, we find that changes in the behaviour of some functionally important species can be dependent on the class of broadband sound (continuous or impulsive). Our study provides evidence that exposing coastal environments to anthropogenic sound fields is likely to have much wider ecosystem consequences than are presently acknowledged.

Concepts: Biodiversity, Species, Ecology, Natural environment, Sustainability, Invertebrate, Environmental science, Mediation


Although it is assumed that epigenetic mechanisms, such as changes in DNA methylation (DNAm), underlie the relationship between adverse intrauterine conditions and adult metabolic health, evidence from human studies remains scarce. Therefore, we evaluated whether DNAm in whole blood mediated the association between prenatal famine exposure and metabolic health in 422 individuals exposed to famine in utero and 463 (sibling) controls. We implemented a two-step analysis, namely, a genome-wide exploration across 342,596 cytosine-phosphate-guanine dinucleotides (CpGs) for potential mediators of the association between prenatal famine exposure and adult body mass index (BMI), serum triglycerides (TG), or glucose concentrations, which was followed by formal mediation analysis. DNAm mediated the association of prenatal famine exposure with adult BMI and TG but not with glucose. DNAm at PIM3 (cg09349128), a gene involved in energy metabolism, mediated 13.4% [95% confidence interval (CI), 5 to 28%] of the association between famine exposure and BMI. DNAm at six CpGs, including TXNIP (cg19693031), influencing β cell function, and ABCG1 (cg07397296), affecting lipid metabolism, together mediated 80% (95% CI, 38.5 to 100%) of the association between famine exposure and TG. Analyses restricted to those exposed to famine during early gestation identified additional CpGs mediating the relationship with TG near PFKFB3 (glycolysis) and METTL8 (adipogenesis). DNAm at the CpGs involved was associated with gene expression in an external data set and correlated with DNAm levels in fat depots in additional postmortem data. Our data are consistent with the hypothesis that epigenetic mechanisms mediate the influence of transient adverse environmental factors in early life on long-term metabolic health. The specific mechanism awaits elucidation.

Concepts: DNA, Gene expression, Metabolism, Adenosine triphosphate, Epigenetics, DNA methylation, Glycolysis, Mediation


BackgroundStudies have shown that a mother’s history of child maltreatment is associated with her child’s experience of internalising and externalising difficulties.AimsTo characterise the mediating pathways that underpin this association.MethodData on a mother’s history of child maltreatment, depression during pregnancy, postnatal depression, maladaptive parenting practices and her child’s experience of maltreatment and internalising and externalising difficulties were analysed in an Avon Longitudinal Study of Parents and Children (ALSPAC) sample of 9397 mother-child dyads followed prospectively from pregnancy to age 13.ResultsMaternal history of child maltreatment was significantly associated with offspring internalising and externalising difficulties. Maternal antenatal depression, postnatal depression and offspring child maltreatment were observed to significantly mediate this association independently.ConclusionsPsychological and psychosocial interventions focused around treating maternal depression, particularly during pregnancy, and safeguarding against adverse childhood experiences could be offered to mothers with traumatic childhood histories to help protect against psychopathology in the next generation.

Concepts: Pregnancy, Childbirth, Longitudinal study, Parent, Sociology, Psychological trauma, Mother, Mediation


In the present study, shame and guilt proneness were investigated in relation to primary and secondary psychopathy, looking at parental care as a possible mediator. A sample of 388 volunteers participated in an on-line study, completing several self-report measurements. Primary psychopathy, robust to parental care and sex of the participant, was associated with lower guilt proneness after a private transgression and lower negative self-evaluations after a public transgression. Secondary psychopathy was not associated with guilt or shame proneness. Paternal care played a mediating role between primary psychopathy and guilt, but only in male participants. High paternal care was associated with lower guilt repair in high psychopathy males, suggesting that a positive father-son relationship might be essential for development of exploitive strategies in primary psychopathy. The results highlight the fundamental differences between primary and secondary psychopathy, and provide support for the idea that primary psychopathy is an evolutionary cheater-strategy.

Concepts: Male, Female, Participation, Sex, Parenting, Psychopathy, Mediation, Shame