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Abstract Background Calcareous outcrops, rocky areas composed of calcium carbonate (CaCO3), often host a diverse, specialized, and threatened biomineralizing fauna. Despite the repeated evolution of physiological and morphological adaptations to colonize these mineral rich substrates, there is a lack of genomic resources for calcareous rock endemic species. This has hampered our ability to understand the genomic mechanisms underlying calcareous rock specialization and manage these threatened species. Results Here, we present a new draft genome assembly of the threatened limestone endemic land snail Oreohelix idahoensis and genome skim data for two other Oreohelix species. The O. idahoensis genome assembly (scaffold N50: 404.19 kb; 86.6% BUSCO genes) is the largest (~ 5.4 Gb) and most repetitive mollusc genome assembled to date (85.74% assembly size). The repetitive landscape was unusually dominated by an expansion of long terminal repeat (LTR) transposable elements (57.73% assembly size) which have shaped the evolution genome size, gene composition through retrotransposition of host genes, and ectopic recombination. Genome skims revealed repeat content is more than 2–3 fold higher in limestone endemic O. idahoensis compared to non-calcareous Oreohelix species. Gene family size analysis revealed stress and biomineralization genes have expanded significantly in the O. idahoensis genome. Conclusions Hundreds of threatened land snail species are endemic to calcareous rock regions but there are very few genomic resources available to guide their conservation or determine the genomic architecture underlying CaCO3 resource specialization. Our study provides one of the first high quality draft genomes of a calcareous rock endemic land snail which will serve as a foundation for the conservation genomics of this threatened species and for other groups. The high proportion and activity of LTRs in the O. idahoensis genome is unprecedented in molluscan genomics and sheds new light how transposable element content can vary across molluscs. The genomic resources reported here will enable further studies of the genomic mechanisms underlying calcareous rock specialization and the evolution of transposable element content across molluscs.

Abstract Background Alzheimer’s disease is the most prevalent cause of dementia in the elderly. Neuronal death and synaptic dysfunctions are considered the main hallmarks of this disease. The latter could be directly associated to an impaired metabolism. In particular, glucose metabolism impairment has demonstrated to be a key regulatory element in the onset and progression of AD, which is why nowadays AD is considered the type 3 diabetes. Methods We provide a thread regarding the influence of glucose metabolism in AD from three different perspectives: (i) as a regulator of the energy source, (ii) through several metabolic alterations, such as insulin resistance, that modify peripheral signaling pathways that influence activation of the immune system (e.g., insulin resistance, diabetes, etc.), and (iii) as modulators of various key post-translational modifications for protein aggregation, for example, influence on tau hyperphosphorylation and other important modifications, which determine its self-aggregating behavior and hence Alzheimer’s pathogenesis. Conclusions In this revision, we observed a 3 edge-action in which glucose metabolism impairment is acting in the progression of AD: as blockade of energy source (e.g., mitochondrial dysfunction), through metabolic dysregulation and post-translational modifications in key proteins, such as tau. Therefore, the latter would sustain the current hypothesis that AD is, in fact, the novel diabetes type 3.

Abstract Background Latin America harbors some of the most biodiverse countries in the world, including Colombia. Despite the increasing use of cutting-edge technologies in genomics and bioinformatics in several biological science fields around the world, the region has fallen behind in the inclusion of these approaches in biodiversity studies. In this study, we used data mining methods to search in four main public databases of genetic sequences such as: NCBI Nucleotide and BioProject, Pathosystems Resource Integration Center, and Barcode of Life Data Systems databases. We aimed to determine how much of the Colombian biodiversity is contained in genetic data stored in these public databases and how much of this information has been generated by national institutions. Additionally, we compared this data for Colombia with other countries of high biodiversity in Latin America, such as Brazil, Argentina, Costa Rica, Mexico, and Peru. Results In Nucleotide, we found that 66.84% of total records for Colombia have been published at the national level, and this data represents less than 5% of the total number of species reported for the country. In BioProject, 70.46% of records were generated by national institutions and the great majority of them is represented by microorganisms. In BOLD Systems, 26% of records have been submitted by national institutions, representing 258 species for Colombia. This number of species reported for Colombia span approximately 0.46% of the total biodiversity reported for the country (56,343 species). Finally, in PATRIC database, 13.25% of the reported sequences were contributed by national institutions. Colombia has a better biodiversity representation in public databases in comparison to other Latin American countries, like Costa Rica and Peru. Mexico and Argentina have the highest representation of species at the national level, despite Brazil and Colombia, which actually hold the first and second places in biodiversity worldwide. Conclusions Our findings show gaps in the representation of the Colombian biodiversity at the molecular and genetic levels in widely consulted public databases. National funding for high-throughput molecular research, NGS technologies costs, and access to genetic resources are limiting factors. This fact should be taken as an opportunity to foster the development of collaborative projects between research groups in the Latin American region to study the vast biodiversity of these countries using ‘omics’ technologies.

Abstract Background Universal parenting campaigns are efficient, cost-effective and can eliminate barriers to accessing conventional, face-to-face parenting interventions. The aims of the CHAMPP4KIDS study were to assess Canadian early childhood providers’ perceptions of the acceptability and feasibility of implementing a universal parenting resource, the Parenting for Lifelong Health tip sheets. Methods Using a convergent mixed method design, an online survey of providers working with families with young children in Ontario, Canada was followed by focus group discussions with a subset of providers to explore their perceptions of using the tip sheets in their professional practice. Results Providers generally perceived the tip sheets to be acceptable but had reservations with respect to the feasibility of distributing the sheets to their clients as standalone, universal parenting resources. Providers agreed the tip sheets covered topics pertinent to caregivers’ concerns, offered useful strategies and, therefore, had the potential to be valuable, engaging resources for families. However, many providers said the sheets would only be effective as complementary resources to facilitated in-person sessions, especially for high-needs families. Conclusion Providers suggested that future iterations of these resources take into consideration more accessible design and formatting, literacy levels, word choice and further cultural adaptation. Insight into the nuances and potential divergence between provider perceptions of universal materials’ acceptability and feasibility can help adapt materials to pre-emptively respond to potential implementation barriers, facilitate intervention fidelity and, ultimately, increase the likelihood of intervention acceptability and feasibility of both providers and caregivers.

Abstract Background The neonatal intensive care unit (NICU) is a complex care environment, with the NICU patient population among the most vulnerable in a hospital setting. Adolescent parents are a unique group within the broader NICU parent population and admission of their infant to the NICU contributes to an already complex situation as adolescent pregnancy and parenting is often associated with a range of psychosocial challenges. How the NICU care context influences care provision for adolescent parents is a significant gap in the NICU parenting and support discourse. Therefore, this study aimed to explore health and social care providers’ perspectives of the NICU care context and how providers perceive the context as influencing the experiences of adolescent parents in the NICU. Methods This was a qualitative, interpretive description study design. In-depth interviews were conducted with providers, including nurses and social workers, caring for adolescent parents in the NICU. Data was collected between December 2019 and November 2020. Data were analyzed concurrently with data collection. Constant comparison, analytic memos, and iterative diagramming techniques were used to challenge developing analytic patterns. Results Providers (n = 23) described how the unit context influenced care provision as well as experiences for adolescent parents. We learned that having a baby in the NICU was perceived by providers as a traumatic experience for parents – impacting attachment, parenting confidence and competence, and mental health. Environmental factors – such as privacy and time – and perceptions that adolescent parents are treated differently in the NICU were also seen as influencing this overall experience. Conclusions Providers involved in the care of adolescent parents in the neonatal intensive care unit described the distinctiveness of this group within the broader parent population and how quality of care may be impacted by contextual factors as well as experiences of age-related stigma. Further understanding of NICU experiences from the parents’ perspectives are warranted. Findings highlight opportunities for strengthened interprofessional collaboration and trauma- and violence-informed care strategies within the neonatal intensive care environment to mitigate the potential negative influence of this experience and improve care for adolescent parents.

Abstract Background Child maltreatment (CM) and peer victimization (PV) are serious issues affecting children and adolescents. Despite the interrelatedness of these exposures, few studies have investigated their co-occurrence and combined impact on health outcomes. The study objectives were to determine the overall and sex-specific prevalence of lifetime exposure to CM and past-month exposure to PV in adolescents, and the impact of CM and PV co-occurrence on non-suicidal self-injury, suicidality, mental health disorders, and physical health conditions. Methods Adolescents aged 14–17 years (n = 2,910) from the 2014 Ontario Child Health Study were included. CM included physical, sexual, and emotional abuse, physical neglect, and exposure to intimate partner violence. PV included school-based, cyber, and discriminatory victimization. Logistic regression was used to compare prevalence by sex, examine independent associations and interaction effects in sex-stratified models and in the entire sample, and cumulative effects in the entire sample. Results About 10% of the sample reported exposure to both CM and PV. Sex differences were as follows: females had increased odds of CM, self-injury, suicidality, and internalizing disorders, and males had greater odds of PV, externalizing disorders, and physical health conditions. Significant cumulative and interaction effects were found in the entire sample and interaction effects were found in sex-stratified models, indicating that the presence of both CM and PV magnifies the effect on self-injury and all suicide outcomes for females, and on suicidal ideation, suicide attempts, and mental health disorders for males. Conclusions Experiencing both CM and PV substantially increases the odds of poor health outcomes among adolescents, and moderating relationships affect females and males differently. Continued research is needed to develop effective prevention strategies and to examine protective factors that may mitigate these adverse health outcomes, including potential sex differences.

Abstract Background Longitudinal studies examining the impact of changes in COVID-19 pandemic-related stressors and experiences, and coping styles on the mental health trajectory of employed individuals during the lockdown are limited. The study examined the mental health trajectories of a sample of employed adults in Hamilton, Ontario during the initial lockdown and after the re-opening following the first wave in Canada. Further, this study also identified the pandemic-related stressors and coping strategies associated with changes in depressive symptoms in employed adults during the COVID-19 pandemic. Methods The InHamilton COVID-19 longitudinal study involved 579 employees aged 22–88 years from a large public university in an urban area of Hamilton, Ontario at baseline (April 2020). Participants were followed monthly with 6 waves of data collected between April and November 2020. A growth mixture modeling approach was used to identify distinct groups of adults who followed a similar pattern of depressive symptoms over time and to describe the longitudinal change in the outcome within and among the identified sub-groups. Results Our results showed two distinct trajectories of change with 66.2% of participants displaying low-consistent patterns of depressive symptoms, and 33.8% of participants displaying high-increasing depressive symptom patterns. COVID-19 pandemic-related experiences including health concerns, caregiving burden, and lack of access to resources were associated with worsening of the depressive symptom trajectories. Frequent use of dysfunctional coping strategies and less frequent use of emotion-focused coping strategies were associated with the high and increasing depressive symptom pattern. Conclusions The negative mental health impacts of the COVID-19 pandemic are specific to subgroups within the population and stressors may persist and worsen over time. Providing access to evidence-informed approaches that foster adaptive coping, alleviate the depressive symptoms, and promote the mental health of working adults is critical.

Abstract Background Executive functions can be adversely affected by contextual risks in the home environment including chaos and parenting challenges. Furthermore, household chaos negatively influences parenting practices. Few studies, however, have examined the role of parenting in the association between household chaos and child executive functions. Methods Using a sample of 128 school-aged children (mean = 61.9 months, SD = 2.0, range 58–68 months) and their mothers, the present study examined direct and indirect effects (via parental responsiveness) of household chaos on child executive functioning. Multi-measures were used including performance-based assessments, behavioural observations, questionnaires, and video-home tours. Results Household chaos had both a direct effect on child executive functions (β = − .31, 95% CI [− .58, − .04]) and an indirect effect (β = − .05, 95% [− .13, − .01]) via parental responsiveness. Further, the indirect effect was only significant for household instability. Conclusion These findings indicate that parental responsiveness may be compromised by household chaos, with implications for the executive functions of school-aged children. Preventative strategies are needed to improve the stability in the home and strengthen parenting practices.

Abstract Background Children’s academic readiness has important implications for subsequent achievement and psychosocial functioning. A growing number of studies are utilizing randomized controlled trials (RCT) to examine whether responsive parenting interventions lead to positive gains in children’s academic readiness. A synthesis of the extant literature is warranted to gain a precise estimate of the causal influence of responsive parenting on academic readiness, as well as to examine moderators that may serve to strengthen or weaken this effect. The main objective of this study will be to conduct a systematic review and meta-analysis of RCTs evaluating the use of responsive parenting interventions to target academic readiness: problem-solving/reasoning, language proficiency, executive functioning, and pre-academic skills (e.g., numeracy/literacy). Methods Studies that took place in the early childhood period (

Abstract Background Both childhood maltreatment (CM) and intimate partner violence (IPV) are public health problems that have been related to a wide range of adverse health consequences. However, studies examining associations between specific types of CM and experiencing IPV in adulthood have yielded conflicting results. Methods Using data from 10,608 men and 11,458 women aged 18 or older from Canada’s 2014 General Social Survey, we examined associations between three types of CM—childhood physical abuse (CPA), childhood sexual abuse (CSA), and childhood exposure to IPV —and subsequent intimate partner violence (IPV) in adulthood (physical, sexual or emotional). Results When potential confounders were controlled, CPA, CSA and childhood exposure to IPV were associated with IPV in adulthood for both sexes (odds ratios, 1.7, 1.8 and 2.0 for men, and 2.2, 2.0 and 2.1 for women). When severity and frequency of CM were examined, a dose-response relationship between all three types of CM and IPV in adulthood was observed among women (meaning that as the severity/frequency of CM increased, the likelihood of reporting IPV also increased); among men, a dose-response relationship was observed only for CPA. Conclusions The association between CM and IPV in adulthood is particularly concerning because experiencing multiple forms of trauma has cumulative effects. Lifespan studies have shown that individuals who experience multiple incidents of abuse exhibit the highest levels of impairment. This underscores the importance of programs to eradicate both CM and IPV. This underscores the importance of programs to eradicate both CM and IPV. Future research should focus on assessing interventions designed to promote healthy relationships and the provision of emotional support and coping mechanisms to children and families in abusive situations.

Abstract Background Nurturing care, in which children are raised in engaging and safe environments, may reduce child stress and shape hypothalamic-pituitary-adrenal axis functioning. Hence, parent-training programs may impact child cortisol levels, as well as behavioral, social and health outcomes. We conducted a systematic review of the impact of parent-training interventions on children’s and caregivers’ cortisol levels, and meta-analyzed the results. Methods In January 2020, searches in PubMed, LILACS, ERIC, Web of Science, Scielo, Scopus, PsycNET and POPLINE databases were conducted, and two independent researchers screened the results for eligible studies – randomized trials that assessed the impact of parent-training interventions on child or caregiver cortisol levels. Random effects were used to pool the estimates, separately for children and caregivers, and for children’s morning and evening cortisol levels, as well as change across the day. Results A total of 27 eligible studies were found. Data from 19 studies were extracted and included in the meta-analyses, with 18 estimates of child cortisol levels and 5 estimates for caregiver cortisol levels. The pooled effect size (standardized mean difference) for the effects of parent training programs on morning child cortisol was 0.01 (95%CI: − 0.14 to 0.16; I2: 47.5%), and for caregivers it was 0.04 (95%CI: − 0.22 to 0.30; I2: 0.0%). Similar null results were observed for child evening cortisol and for the slope between morning and evening child cortisol. No evidence of publication bias was found. Conclusion Existing evidence shows no effect of parent-training interventions on child or caregiver post-intervention cortisol. Researchers are encouraged to adopt standardized protocols to improve evaluation standards, to test for intervention effects on psychosocial outcomes that are theorized to mediate the effects on biomarkers, and to use additional biomarkers for chronic stress.

Abstract Background Effective strategies for participant retention are critical in health research to ensure validity, generalizability and efficient use of resources. Yet standardized guidelines for planning and reporting on retention efforts have been lacking. As with randomized controlled trial (RCT) and systematic review (SR) protocols, retention protocols are an opportunity to improve transparency and rigor. An RCT being conducted in British Columbia (BC), Canada provides a case example for developing a priori retention frameworks for use in protocol planning and reporting. Methods The BC Healthy Connections Project RCT is examining the effectiveness of a nurse home-visiting program in improving child and maternal outcomes compared with existing services. Participants (N = 739) were girls and young women preparing to parent for the first time and experiencing socioeconomic disadvantage. Quantitative data were collected upon trial entry during pregnancy and during five follow-up interviews until participants’ children reached age 2 years. A framework was developed to guide retention of this study population throughout the RCT. We reviewed relevant literature and mapped essential retention activities across the study planning, recruitment and maintenance phases. Interview completion rates were tracked. Results Results from 3302 follow-up interviews (in-person/telephone) conducted over 4 years indicate high completion rates: 90% (n = 667) at 34 weeks gestation; and 91% (n = 676), 85% (n = 626), 80% (n = 594) and 83% (n = 613) at 2, 10, 18 and 24 months postpartum, respectively. Almost all participants (99%, n = 732) provided ongoing consent to access administrative health data. These results provide preliminary data on the success of the framework. Conclusions Our retention results are encouraging given that participants were experiencing considerable socioeconomic disadvantage. Standardized retention planning and reporting may therefore be feasible for health research in general, using the framework we have developed. Use of standardized retention protocols should be encouraged in research to promote consistency across diverse studies, as now happens with RCT and SR protocols. Beyond this, successful retention approaches may help inform health policy-makers and practitioners who also need to better reach, engage and retain underserved populations. Trial registration ClinicalTrials.gov , NCT01672060 . Registered on 24 August 2012.

Abstract Background Child maltreatment affects a significant number of children globally. Strategies have been developed to identify children suspected of having been exposed to maltreatment with the aim of reducing further maltreatment and impairment. This systematic review evaluates the accuracy of strategies for identifying children exposed to maltreatment. Methods We conducted a systematic search of seven databases: Medline, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, Cochrane Libraries, Sociological Abstracts and the Education Resources Information Center. We included studies published from 1961 to July 2, 2019 estimating the accuracy of instruments for identifying potential maltreatment of children, including neglect, physical abuse, emotional abuse, and sexual abuse. We extracted data about accuracy and narratively synthesised the evidence. For five studies—where the population and setting matched known prevalence estimates in an emergency department setting—we calculated false positives and negatives. We assessed risk of bias using QUADAS-2. Results We included 32 articles (representing 31 studies) that evaluated various identification strategies, including three screening tools (SPUTOVAMO checklist, Escape instrument, and a 6-item screening questionnaire for child sex trafficking). No studies evaluated the effects of identification strategies on important outcomes for children. All studies were rated as having serious risk of bias (often because of verification bias). The findings suggest that use of the SPUTOVAMO and Escape screening tools at the population level (per 100,000) would result in hundreds of children being missed and thousands of children being over identified. Conclusions There is low to very low certainty evidence that the use of screening tools may result in high numbers of children being falsely suspected or missed. These harms may outweigh the potential benefits of using such tools in practice (PROSPERO 2016:CRD42016039659).

Abstract Background Slapping/spanking is related to a number of poor health outcomes. Understanding what factors are related to the increased or decreased use of spanking/slapping is necessary to inform prevention. This study used a population-based sample to determine the prevalence of slapping/spanking reported by youth; the relationship between sociodemographic factors and slapping/spanking; and the extent to which parental exposures to victimization and maltreatment in childhood and current parental mental health, substance use and family circumstances, are associated with youth reports of slapping/spanking. Methods Data were from the 2014 Ontario Child Health Study, a provincially representative sample of households with children and youth aged 4–17 years. Self-reported lifetime slapping/spanking prevalence was determined using a sub-sample of youth aged 14–17 years (n = 1883). Parents/primary caregivers (i.e., person most knowledgeable (PMK) of the youth) self-reported their own childhood experiences including bullying victimization, slapping/spanking and child maltreatment, and current mental health, substance use and family circumstances including mental health functioning and emotional well-being, alcohol use, smoking, marital conflict and family functioning. Analyses were conducted in 2018. Results Living in urban compared to rural residence and family poverty were associated with decreased odds of slapping/spanking. PMK childhood experiences of physical and verbal bullying victimization, spanking, sexual abuse, emotional abuse, and exposure to physical intimate partner violence were associated with increased odds of youth reported slapping/spanking (adjusted odds ratio [AOR] ranged from 1.33–1.77). PMK experiences of physical abuse and exposure to emotional/verbal intimate partner violence in childhood was associated with decreased odds of youth reported slapping/spanking (AOR = 0.72 and 0.88, respectively). PMK’s higher levels of marital conflict, languishing to moderate mental health functioning and emotional well-being, and moderate or greater alcohol use were associated with increased odds of youth reported slapping/spanking (AOR ranged from 1.36–1.61). Conclusions It may be important to consider parent/primary caregiver’s childhood experiences with victimization and maltreatment along with their current parental mental health, substance use and family circumstances when developing and testing strategies to prevent slapping/spanking.

Abstract Background Maternal exposure to socioeconomic disadvantage increases the risk of child injuries and subsequent child developmental and mental health problems — particularly for young mothers. To inform early intervention planning, this research therefore aimed to describe the health and social adversities experienced by a cohort of girls and young women in early pregnancy in British Columbia (BC), Canada. Methods Participants were recruited for the BC Healthy Connections Project (BCHCP), a randomized controlled trial examining the effectiveness of Nurse-Family Partnership, a home visitation program, in improving child and maternal outcomes. Baseline data were collected from 739 participants on trial entry. Participants were selected on the basis of preparing to parent for the first time and experiencing socioeconomic disadvantage. Analyses involved descriptive statistics and age-group comparisons. Results Most participants reported having low income (84%), having limited education (52%) and being single (91%) at trial entry. Beyond these eligibility criteria, other health and social adversities included: housing instability (52%); severe anxiety or depression (47%); other diagnosed mental disorders (22%); prenatal nicotine and cannabis use (27 and 21%); physical health problems (20%); child maltreatment when younger (56%); and intimate partner violence recently (50%). As well, few (29%) had received income assistance entitlements. More than two thirds (70%) were experiencing four or more forms of adversity. Age-group differences were observed for cognitive functioning, being single, low income, limited education, psychological distress and service use (p-value ≤0.05). Conclusions This cohort was selected on the basis of socioeconomic disadvantage. Yet all participants were experiencing substantial added adversities — at higher rates than other Canadians. Furthermore, despite Canada’s public programs, these pregnant girls and young women were not being adequately reached by social services. Our study adds new data to inform early intervention planning, suggesting that unacceptably high levels of socioeconomic disadvantage exist for some young British Columbians. Therefore greater health and social supports and services are warranted for these young mothers and their children. Trial registration Registered August 24, 2012 with ClinicalTrials.gov Identifier: NCT01672060. Active not recruiting.

Abstract Background Family medicine (FM) residents choose among a range of options as they enter practice, including practice model, clinical domains, settings, and populations. The choices they make have implications for primary care workforce planning and may differ between FM residents who are parents and those who are not, as well as between male and female FM residents. We investigate whether parenthood shapes intentions among FM residents entering practice and whether the effect of parenthood differs between male and female FM residents. Methods We conducted cross-sectional analysis of national survey data collected from FM residents in Canadian residency programs by the College of Family Physicians of Canada between 2014 and 2017. The survey captures information on intentions for comprehensive or focused practice, practice model, clinical domains, practice setting, and populations. We used chi-square tests and multivariable logistic regression to investigate the relationships between parenthood, gender, and practice intentions, adjusting for other physician personal characteristics. Results Almost a quarter of FM residents were parents or became parents during residency. Intentions for the provision comprehensive care were higher among parents, and intentions for clinically focused practice were lower. Differences in intentions for practice models, domains, and settings/population were primarily by gender, though in several cases the effects of parenthood differed between female and male FM residents. Even during residency, the effects of parenthood differ between male and female residents: while three quarters of male parents finish residency in two years, fewer than half of female parents do. Conclusions Both parenthood and gender independently shape practice intentions, but the effect of parenthood differs for male and female FM residents. Supporting FM residents who are parents may positively impact the quality and availability of primary care services, especially since parents are more likely to report intentions to provide comprehensive care soon after entering practice.

Abstract Background Children in many low- and middle-income countries (LMICs) are at high risk for exposure to violence and later violent behaviour. The World Health Organization has declared an urgent need for the evaluation and implementation of low-cost parenting interventions in LMICs to prevent violence. Two areas of significant early risk are harsh parenting and poor child cognitive and socio-emotional development. Parenting interventions suitable for LMIC contexts have been developed targeting these risk factors and have been shown to have promising effects. However, their impact on child aggression, a key precursor of violence, has yet to be determined. The Pelotas Trial of Parenting Interventions for Aggression (PIÁ) has been designed to address this issue. Methods We are conducting a randomised controlled trial to evaluate two early parenting interventions for mothers of children aged between 30 and 42 months in a Brazilian city. The first of these, dialogic book-sharing (DBS), aims to promote child cognitive and socio-emotional development; and the second, the ACT Raising Safe Kids Program (ACT), is designed to reduce harsh parenting. These interventions are being compared with a control group receiving neither intervention. Three hundred and sixty-nine families in a birth cohort are being randomly allocated to one of the three groups (DBS, ACT, Control). Facilitators deliver the interventions to groups of five to 10 mothers at weekly sessions for 8 weeks in DBS and 9 weeks in ACT. Independent assessments of parenting and child development are being made before the interventions, shortly afterwards, and at follow-up 6 months later. The primary outcome is child aggression, and the two main secondary outcomes are: (1) child cognitive and socio-emotional development and (2) harsh parenting. Longer-term outcomes will be investigated as the birth cohort is followed into late childhood, adolescence, and adulthood. Discussion The Pelotas Trial of Parenting Interventions for Aggression (PIÁ) aims to evaluate the impact of two early parenting interventions on child aggression and several other key risk factors for the development of violence, including aspects of parenting and child cognition and socio-emotional functioning. The study is being carried out in a LMIC context where violence constitutes a major social and health burden. Since the two interventions are brief and, with modest levels of training, readily deliverable in LMIC settings, a demonstration that they benefit parenting and reduce risk factors for violence would be of major significance. Trial registration Brazilian Ministry of Health Register of Clinical Trials, ID: RBR-2kwfsk. Registered on 6 June 2018.