Causal inference in multi-cohort studies using the target trial approach

Longitudinal cohort studies provide the opportunity to examine causal effects of complex exposures on long-term health outcomes. Utilizing data from multiple cohorts has the potential to add further benefit by improving precision of estimates through data pooling and allowing examination of effect heterogeneity across contexts. However, the interpretation of findings can be complicated by biases that may be compounded when pooling data or may contribute to discrepant findings when analyses are replicated across cohorts. Here we extend the target trial framework, already well established as a powerful tool for causal inference in single-cohort studies, to address the specific challenges that can arise in the multi-cohort setting. The approach considers the target trial as a central point of reference, as opposed to comparing one study to another. This enables clear definition of the target estimand and systematic consideration of sources of bias within each cohort and additional sources of bias arising from data pooling. Consequently, analyses can be designed to reduce these biases and the resulting findings appropriately interpreted. We use a case study to demonstrate the approach and its potential to strengthen causal inference in multi-cohort studies through improved analysis design and clarity in the interpretation of findings.Comment: 34 pages, 3 figure

Adolescence and the next generation

Adolescent growth and social development shape the early development of offspring from preconception through to the post-partum period through distinct processes in males and females. At a time of great change in the forces shaping adolescence, including the timing of parenthood, investments in today\u27s adolescents, the largest cohort in human history, will yield great dividends for future generations

Pre-conception self-harm, maternal mental health and mother-infant bonding problems:a 20-year prospective cohort study

Background: Self-harm in young people is associated with later problems in social and emotional development. However, it is unknown whether self-harm in young women continues to be a marker of vulnerability on becoming a parent. This study prospectively describes the associations between pre-conception self-harm, maternal depressive symptoms and mother&ndash;infant bonding problems.MethodsThe Victorian Intergenerational Health Cohort Study (VIHCS) is a follow-up to the Victorian Adolescent Health Cohort Study (VAHCS) in Australia. Socio-demographic and health variables were assessed at 10 time-points (waves) from ages 14 to 35, including self-reported self-harm at waves 3&ndash;9. VIHCS enrolment began in 2006 (when participants were aged 28&ndash;29 years), by contacting VAHCS women every 6 months to identify pregnancies over a 7-year period. Perinatal depressive symptoms were assessed with the Edinburgh Postnatal Depression Scale during the third trimester, and 2 and 12 months postpartum. Mother&ndash;infant bonding problems were assessed with the Postpartum Bonding Questionnaire at 2 and 12 months postpartum.ResultsFive hundred sixty-four pregnancies from 384 women were included. One in 10 women (9.7%) reported pre-conception self-harm. Women who reported self-harming in young adulthood (ages 20&ndash;29) reported higher levels of perinatal depressive symptoms and mother&ndash;infant bonding problems at all perinatal time points [perinatal depressive symptoms adjusted &beta; = 5.40, 95% confidence interval (CI) 3.42&ndash;7.39; mother&ndash;infant bonding problems adjusted &beta; = 7.51, 95% CI 3.09&ndash;11.92]. There was no evidence that self-harm in adolescence (ages 15&ndash;17) was associated with either perinatal outcome.ConclusionsSelf-harm during young adulthood may be an indicator of future vulnerability to perinatal mental health and mother&ndash;infant bonding problems.</jats:sec

Associations between maternal psychological distress and mother-infant bonding: a systematic review and meta-analysis

Purpose: Maternal psychological distress and mother-infant bonding problems each predict poorer offspring outcomes. They are also related to each other, yet the extensive literature reporting their association has not been meta-analysed. Methods: We searched MEDLINE, PsycINFO, CINAHL, Embase, ProQuest DTG, and OATD for English-language peer-reviewed and grey literature reporting an association between mother-infant bonding, and multiple indicators of maternal psychological distress. Results: We included 133 studies representing 118 samples; 99 samples (110,968 mothers) were eligible for meta-analysis. Results showed concurrent associations across a range of timepoints during the first year postpartum, between bonding problems and depression (r = .27 [95% CI 0.20, 0.35] to r = .47 [95% CI 0.41, 0.53]), anxiety (r = .27 [95% CI 0.24, 0.31] to r = .39 [95% CI 0.15, 0.59]), and stress (r = .46 [95% CI 0.40, 0.52]). Associations between antenatal distress and subsequent postpartum bonding problems were mostly weaker and with wider confidence intervals: depression (r = .20 [95% CI 0.14, 0.50] to r = .25 [95% CI 0.64, 0.85]), anxiety (r = .16 [95% CI 0.10, 0.22]), and stress (r = .15 [95% CI − 0.67, 0.80]). Pre-conception depression and anxiety were associated with postpartum bonding problems (r = − 0.17 [95% CI − 0.22, − 0.11]). Conclusion: Maternal psychological distress is associated with postpartum mother-infant bonding problems. Co-occurrence of psychological distress and bonding problems is common, but should not be assumed. There may be benefit in augmenting existing perinatal screening programs with well-validated mother-infant bonding measures

Preconception personality disorder and antenatal maternal mental health:a population-based cohort study

BACKGROUND: Prior anxiety and depression have been identified as risk factors for maternal perinatal mental health problems, but other preconception mental disorders have not been prospectively examined. This study investigated prospectively whether women with preconception personality disorder have increased rates of antenatal anxiety and/or depressive symptoms. METHODS: 244 women in a population cohort were assessed for personality disorder at age 24 using the Standardised Assessment of Personality. Five to twelve years later, women were screened with the Clinical Interview Schedule, Revised Anxiety Subscale and the Edinburgh Postnatal Depression Scale during the third trimester of 328 pregnancies. RESULTS: Preconception personality disorder was associated with a three-fold increase in the odds of antenatal anxiety symptoms, which remained with adjustment for preconception background factors and preconception common mental disorder (adjusted OR 2.84, 95% CI 1.31-6.15). Preconception personality disorder was associated with doubled odds of antenatal depressive symptoms, however this was attenuated with adjustment for preconception background factors and preconception common mental disorder (adjusted OR 1.98, 95% CI 0.81-4.81). LIMITATIONS: Our findings are restricted to pregnant women aged 29-35 years. Anxiety and depression may have been under-identified because they were assessed at a single antenatal time point. Residual confounding of the associations by preconception common mental disorder at other time points may have occurred. CONCLUSIONS: Women with personality disorder are at heightened risk of anxiety symptoms in pregnancy, over and above risks associated with prior common mental disorder. This raises a possibility that pregnancy brings particular emotional challenges for women with personality disorders

Adolescence and the next generation.

Adolescent growth and social development shape the early development of offspring from preconception through to the post-partum period through distinct processes in males and females. At a time of great change in the forces shaping adolescence, including the timing of parenthood, investments in today's adolescents, the largest cohort in human history, will yield great dividends for future generations

Targeting DNA Damage Response and Replication Stress in Pancreatic Cancer

Background and aims: Continuing recalcitrance to therapy cements pancreatic cancer (PC) as the most lethal malignancy, which is set to become the second leading cause of cancer death in our society. The study aim was to investigate the association between DNA damage response (DDR), replication stress and novel therapeutic response in PC to develop a biomarker driven therapeutic strategy targeting DDR and replication stress in PC. Methods: We interrogated the transcriptome, genome, proteome and functional characteristics of 61 novel PC patient-derived cell lines to define novel therapeutic strategies targeting DDR and replication stress. Validation was done in patient derived xenografts and human PC organoids. Results: Patient-derived cell lines faithfully recapitulate the epithelial component of pancreatic tumors including previously described molecular subtypes. Biomarkers of DDR deficiency, including a novel signature of homologous recombination deficiency, co-segregates with response to platinum (P &lt; 0.001) and PARP inhibitor therapy (P &lt; 0.001) in vitro and in vivo. We generated a novel signature of replication stress with which predicts response to ATR (P &lt; 0.018) and WEE1 inhibitor (P &lt; 0.029) treatment in both cell lines and human PC organoids. Replication stress was enriched in the squamous subtype of PC (P &lt; 0.001) but not associated with DDR deficiency. Conclusions: Replication stress and DDR deficiency are independent of each other, creating opportunities for therapy in DDR proficient PC, and post-platinum therapy

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to &lt;90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], &gt;300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of &lt;15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P&lt;0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P&lt;0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years