Use of directed acyclic graphs (DAGs) to identify confounders in applied health research: review and recommendations

Low-dose heparin sodium as a protective factor against bronchiolitis obliterans formation after adenovirus infection

BACKGROUND

Adenovirus (ADV) pneumonia in children is a significant contributor to the occurrence of post-infectious bronchiolitis obliterans (BO). Heparin sodium has known anti-inflammatory, immunomodulatory, and tissue repair properties. However, its role in treating BO after ADV infection remains unclear.

METHODS

A retrospective analysis was conducted on 793 children diagnosed with ADV pneumonia and hospitalized in the southern region from January 2019 to December 2019. Among them, 307 cases were classified as single ADV pneumonia. We utilized directed acyclic graphs to analyze the causal relationships between various variables, which further helped us identify the independent and confounding variables for constructing our regression model. Propensity score matching (PSM) was also employed to control for confounding variables that could not be intervened in this study, ensuring baseline level equilibrium and correction. We utilized univariate logistic regression analysis to explore the factors influencing BO development after ADV pneumonia.

RESULTS

Among the 793 children diagnosed with ADV pneumonia, 86 cases (10.84%) progressed to BO. The proportion of heparin use was higher in the non-BO group than in the BO group after PSM. The univariate regression analysis revealed that acute respiratory failure, neurological involvement and fibrinogen (FIB) were risk factors for the development of BO in ADV pneumonia cases (OR > 1, p < 0.05), but low-dose heparin sodium treatment and hemoglobin (OR < 1, p < 0.05) exhibited protective effects against BO formation. Among the 307 children with single ADV pneumonia (excluding confounding factors), 33 cases (10.75%) developed BO. The univariate regression analysis further indicated that fever duration, acute respiratory failure and FIB were risk factors for the development of BO in single ADV pneumonia (OR > 1, p < 0.05), while low-dose heparin sodium treatment (OR < 1, p < 0.05) was protective against BO formation after a single ADV pneumonia.

CONCLUSION

Low-dose heparin sodium treatment may be a protective factor against the development of BO after ADV pneumonia infection.

An association study of depressive symptoms in adult couples over 50 years of age

BACKGROUND

Depression can lead to reduced physical activity, reduced quality of life, and self-sadness or even suicide, resulting in a huge burden of disease and financial loss.

OBJECTIVE

To study the associated factors of depressive symptoms in adult couples over the age of 50.

METHODS

The study collected data from the Survey of Health, Ageing and Retirement in Europe (SHARE) in 2013, 2015, 2017 and 2019/2020, and extracted couples over the age of 50. Logistic regression was used to analyze the associated factors of depressive symptoms in couples.

RESULTS

Binary Logistic regression showed the husbands' age (OR: 1.41, 95%CI: (1.11, 1.80)) and social activities (OR: 0.60, 95%CI: (0.45, 0.79)) were associated with depressive symptoms in wives. Wives' education level (OR: 0.62, 95%CI: (0.46, 0.85)), life satisfaction (OR: 0.57, 95%CI: (0.39, 0.84)) and number of chronic diseases (OR: 1.38, 95%CI: (1.10, 1.73)) were associated with depressive symptoms in husbands. Multinomial logistic regression found that couple's age "≥ 65 years" (OR: 1.45, 95%CI: (1.11, 1.90)), "low" education level (OR: 1.64, 95%CI: (1.07, 2.52)), self-rated health "good" (OR: 0.48, 95%CI: (0.29, 0.80)), life satisfaction "very satisfied" (OR: 0.48, 95%CI: (0.31, 0.75)) and "having" social activities (OR: 0.34, 95%CI: (0.19, 0.60)) were associated with the risk of depressive symptoms in couples. Having "≥ 2" chronic diseases (OR: 1.94, 95%CI: (1.22, 3.10)) was also associated with depressive symptoms in couples.

CONCLUSION

Age, education level, social activities, life satisfaction, self-rated health and number of chronic diseases were associated with depressive symptoms in both individuals and couples.

Sex-Specific Impact of Serum Calcium Levels on Acute Coronary Syndrome Risk: A 19-Year Cohort Study in Korea

Background: This study aims to investigate the association between serum calcium levels and acute coronary syndrome (ACS) risk, examining whether this relationship differs by sex, given the known differences in calcium metabolism and hormonal influences between males and females. Methods: Utilizing the Korean Genome Epidemiology Study (KoGES) prospective cohort data, our primary exposure variables were serum calcium level and sex. The incidence of ACS served as the main outcome of interest. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression analysis. An interaction analysis was conducted to assess the interaction effect of calcium level and sex on ACS incidence. Results: After adjusting for confounding variables, high calcium intake did not significantly increase ACS incidence, with a hazard ratio (HR) of 1.07 (95% CI: 0.90-1.26). There was also no significant difference in ACS risk between females and males (HR: 0.81, 95% CI: 0.61-1.04). However, interaction effect analysis revealed that higher calcium levels were associated with an increased risk of ACS only in females (HR: 1.24, 95% CI: 1.07-1.58), whereas the association in males was not statistically significant (HR: 0.90, 95% CI: 0.71-1.15). Conclusion: Our study results indicate that elevated serum calcium levels alone did not independently increase the risk of ACS; however, high serum calcium levels were associated with an increased risk of ACS in females but not in males, underscoring the importance of sex-specific factors in assessing and managing ACS risk and highlighting the necessity for personalized medical approaches to improve cardiovascular health outcomes for women.

Association between the existence of neonatal congenital anomalies and maternal postpartum depression up to 6 months after delivery: The Japan Environment and Children's Study

BACKGROUND

Postpartum depression (PPD) is a significant public health concern; however, its association with congenital anomalies (CAs) remains understudied. This study investigated the relationship between CAs and PPD risk and identified persistent patterns of PPD among mothers of infants with and without CAs.

METHODS

We analysed data from 86,464 mother-child pairs in the Japan Environment and Children's Study. PPD was assessed using the Edinburgh Postnatal Depression Scale at 1 and 6 months postpartum. Bayesian multiple log-binomial regression was used to examine associations between CAs and PPD.

RESULTS

The risk ratios (RRs) of PPD were higher in the CAs group than in the Non-CAs group at 1 month (RR = 1.06, 95% credible interval [CrI] = [1.00, 1.12]) and 6 months (RR = 1.11, 95% CrI = [1.04, 1.18]) postpartum. Four PPD patterns were identified: persistent, recovered, late-onset and resilient. Mothers of neonates with CAs on both late-onset (median OR = 1.13, 95% CrI = [1.02, 1.25]) and persistent patterns (median OR = 1.13, 95% CrI = [1.03, 1.24]) tended to have positive associations with CAs compared with the resilient group.

LIMITATIONS

Reliance on self-reported PPD measures may introduce bias and lack of differentiation between types and severities of CAs, while the study's focus on mothers alone without including fathers may not capture the full spectrum of parental mental health impacts.

CONCLUSION

This study suggests that mothers of neonates with CAs have a significantly increased risk of PPD, which persists up to 6 months after delivery.

Early-life environmental exposures and the risk of endometriosis/adenomyosis in the NutriNet-Santé cohort

OBJECTIVE

The etiology of endometriosis is poorly known; established risk factors are limited and few environmental risk factors have been identified. We aimed to explore the associations between several perinatal and childhood environmental exposures and the risk of endometriosis/adenomyosis in women.

METHODS

This study was based on NutriNet-Santé, an ongoing web-based prospective cohort following-up several tens of thousands of French adults since 2009. The analysis included 25,251 women with health data available who completed a self-administered questionnaire on perinatal and childhood exposures in 2019. Associations with self-reported endometriosis/adenomyosis were investigated using multivariable logistic regression models, adjusted for potential confounders identified through direct acyclic graphs.

RESULTS

Among women, 1126 (4.5 %) self-reported a diagnosis of endometriosis/adenomyosis. Endometriosis/adenomyosis was positively associated with a low birth weight (<2500 g vs. ≥2500 g: adjusted odds-ratio (aOR) = 1.43, 95 % confidence interval (95 % CI) = 1.03-2.00), exposure to maternal smoking during pregnancy (aOR = 1.86, 95 % CI = 1.33-2.61), daycare attendance (aOR = 1.61, 95 % CI = 1.11-2.33), exposure to pets in childhood (both cat and dog vs. no animals: aOR = 1.23, 95 % CI = 1.08-1.41), and mold exposure in housing during childhood (aOR = 1.42, 95 % CI = 1.15-1.74). Conversely, living on a farm during childhood (aOR = 0.77, 95 % CI = 0.62-0.97) and having farmer parents (aOR = 0.72, 95 % CI = 0.54-0.97) were inversely associated with endometriosis. Maternal age at birth, birth length, prematurity, mode of delivery, or exposure to breastfeeding was not associated with endometriosis/adenomyosis.

CONCLUSION

Findings from this large population-based study among French adult women suggest associations between several perinatal and childhood exposures and endometriosis/adenomyosis. Research on early-life and childhood environments with endometriosis/adenomyosis might have important implications for the primary prevention of endometriosis and adenomyosis.

Confounder adjustment in observational studies investigating multiple risk factors: a methodological study

BACKGROUND

Confounder adjustment is critical for accurate causal inference in observational studies. However, the appropriateness of methods for confounder adjustment in studies investigating multiple risk factors, where the factors are not simply mutually confounded, is often overlooked. This study aims to summarise the methods for confounder adjustment and the related issues in studies investigating multiple risk factors.

METHODS

A methodological study was performed. We searched PubMed from January 2018 to March 2023 to identify cohort and case-control studies investigating multiple risk factors for three chronic diseases (cardiovascular disease, diabetes and dementia). Study selection and data extraction were conducted independently by two reviewers. The study objectives were grouped into two categories: widely exploring potential risk factors and examining specific risk factors. The methods for confounder adjustment were classified based on a summarisation of the included studies, identifying six categories: (1) each risk factor was adjusted for potential confounders separately (the recommended method); (2) all risk factors were mutually adjusted (i.e. including all factors in a multivariable model); (3) all risk factors were adjusted for the same confounders separately; (4) all risk factors were adjusted for the same confounders with some factors being mutually adjusted; (5) all risk factors were adjusted for the same confounders with mutual adjustment among them being unclear; and (6) unable to judge. All data were descriptively analysed.

RESULTS

A total of 162 studies were included, with 88 (54.3%) exploring potential risk factors and 74 (45.7%) examining specific risk factors. The current status of confounder adjustment was unsatisfactory: only ten studies (6.2%) used the recommended method, all of which aimed at examining several specific risk factors; in contrast, mutual adjustment was adopted in over 70% of the studies. The remaining studies either adjusted for the same confounders across all risk factors, or unable to judge.

CONCLUSIONS

There is substantial variation in the methods for confounder adjustment among studies investigating multiple risk factors. Mutual adjustment was the most commonly adopted method, which might lead to overadjustment bias and misleading effect estimates. Future research should avoid indiscriminately including all risk factors in a multivariable model to prevent inappropriate adjustment.

Confounder selection in firearm policy research: a scoping review

Legislative firearm policies are often proposed as a way of preventing firearm-related harm. Confounding is a substantial threat to accurately estimating the causal effects of firearm policies. This scoping review characterizes the selection of potential confounders in US firearm policy evaluations in the health sciences literature. We identified empirical research articles indexed in PubMed from January 1, 2000, to January 9, 2021, that examined any of 18 prespecified firearm policies and extracted key study elements, including the exposure (firearm policy), outcomes, potential confounders adjusted for in analyses, and study approach (ie, static, uncontrolled pre-post, and controlled pre-post). There was wide variation in potential confounders within study approach/policy outcome combinations. The most common potential confounders included sociodemographic and economic variables, rurality/urbanicity, violent crime, law enforcement-related variables, alcohol use, and firearm access (mostly measured via proxies for firearm ownership). Firearm policies other than the policy being evaluated were included in the adjustment set in 23% to 44% of studies, depending on the study approach. Confounder selection was most often said to be based on prior research (n = 49, 40%) or not explicitly stated (n = 48, 39%). This scoping review provides a comprehensive resource for critically appraising the firearm policy literature and offers considerations to support more rigorous confounding control in future firearm policy research.

A critical approach to research on perioperative pain management

Optimal postoperative pain management is a prerequisite for enhancing functional recovery after surgery. However, many studies assessing analgesic interventions have limitations. Consequently, further improvements in study design are urgently needed. In this focused editorial, we critically review prevalent trial designs and outcome measures including treatment-related adverse events evaluating analgesic interventions. Novel clinical trial designs should improve efficiency and enhance the likelihood of detecting relevant treatment effects. Cohort and database studies using propensity score matching and directed acyclic graphs could provide real-world generalisable information. Procedure-specific and patient-specific trials should allow identification of subpopulations most likely to benefit from a particular intervention after a specific surgical procedure and thus ascertain optimal analgesic strategies in challenging populations.

The Association Between Periconceptual Maternal Dietary Patterns and Miscarriage Risk in Women With Recurrent Miscarriages: A Multicentre Cohort Study

OBJECTIVE

To examine the association between periconceptual maternal diet and miscarriage risk among women with recurrent miscarriages.

DESIGN

Prospective multicentre cohort study (Tommy's Net).

SETTING

Three university hospital research centres in the United Kingdom.

POPULATION

1035 women with a baseline history of two or more miscarriages.

METHODS

We analysed baseline dietary data from a 10-item Food Frequency Questionnaire (FFQ). For individual food category analyses, we used multivariable Poisson regression following adjustment for maternal confounders and paternal dietary patterns. For whole diet analyses, ordinal principal component analysis (PCA) was used to identify common dietary patterns. Results were presented as relative risks (RR) with 95% confidence intervals (CI) and accompanying p-values.

MAIN OUTCOME MEASURES

Miscarriage rate, defined as the rate of spontaneous pregnancy loss (< 24 weeks of gestation) relative to the total number of pregnancies (miscarriages and live births).

RESULTS

High consumption of fruit and nuts (almonds and walnuts) was associated with lower miscarriage risk (fruit 226/662 (34.1%) vs. 38/77 (49.4%), RR 0.66, 95% CI 0.51 to 0.85, p = 0.001; nuts 47/152 (30.9%) vs. 220/613 (35.9%), RR 0.73, 95% CI 0.54 to 0.98, p = 0.039). High red meat intake was associated with a possible increase in miscarriage risk (6/12 (50.0%) vs. 165/469 (35.2%), RR 1.86, 95% CI 1.10 to 3.16, p = 0.022). The association with miscarriage risk was unclear for other food groups, including fresh vegetables, white meat, fish, dairy, eggs, soya and chocolate, due to imprecise point estimates. Through PCA, we identified three data-derived dietary patterns. Yet, no distinct relationship emerged between these dietary patterns and miscarriage risk.

CONCLUSIONS

A maternal diet rich in fresh fruits and nuts is associated with a lower miscarriage risk among women with a history of recurrent miscarriage.

TRAIL REGISTRATION

Tommy's Net (ISRCTN17732518) https://www.isrctn.com/ISRCTN17732518. Analysis plan (OSF zp7cs) https://osf.io/zp7cs.

How to develop causal directed acyclic graphs for observational health research: a scoping review

Causal directed acyclic graphs (DAGs) serve as intuitive tools to visually represent causal relationships between variables. While they find widespread use in guiding study design, data collection and statistical analysis, their adoption remains relatively rare in the domain of psychology. In this paper we describe the relevance of DAGs for health psychology, review guidelines for developing causal DAGs, and offer recommendations for their development. A scoping review searching for papers and resources describing guidelines for DAG development was conducted. Information extracted from the eligible papers and resources (n = 11) was categorised, and results were used to formulate recommendations. Most records focused on DAG development for data analysis, with similar steps outlined. However, we found notable variations on how to implement confounding variables (i.e., sequential inclusion versus exclusion). Also, how domain knowledge should be integrated in the development process was scarcely addressed. Only one paper described how to perform a literature search for DAG development. Key recommendations for causal DAG development are provided and discussed using an illustrative example.

Elucidating the causal relationship of mechanical power and lung injury: a dynamic approach to ventilator management

BACKGROUND

Mechanical power (MP) serves as a crucial predictive indicator for ventilator-induced lung injury and plays a pivotal role in tailoring the management of mechanical ventilation. However, its application across different diseases and stages remains nuanced.

METHODS

Using AmsterdamUMCdb, we conducted a retrospective study to analyze the causal relationship between MP and outcomes of invasive mechanical ventilation, specifically SpO2/FiO2 ratio (P/F) and ventilator-free days at day 28 (VFD28). We employed causal inferential analysis with backdoor linear regression and double machine learning, guided by directed acyclic graphs, to estimate the average treatment effect (ATE) in the whole population and conditional average treatment effect (CATE) in the individual cohort. Additionally, to enhance interpretability and identify MP thresholds, we conducted a simulation analysis.

RESULTS

In the study, we included 11,110 unique admissions into analysis, of which 58.3% (6391) were surgical admissions. We revealed a negative and significant causal effect of median MP on VFD28, with estimated ATEs of -0.135 (95% confidence interval [CI]: -0.15 to -0.121). The similar effect was not observed in Maximal MP and minimal MP. The effect of MP was more pronounced in the medical subgroup, with a CATE of -0.173 (95% CI: -0.197 to -0.143) determined through backdoor linear regression. Patients with cardio, respiratory, and infection diagnoses, who required long-term intubation, sustained higher impact on CATEs across various admission diagnoses. Our simulations showed that there is no single MP threshold that can be applied to all patients, as the optimal threshold varies depending on the patient's condition.

CONCLUSION

Our study underscores the importance of tailoring MP adjustments on an individualized basis in ventilator management. This approach opens up new avenues for personalized treatment strategies and provides fresh insights into the real-time impact of MP in diverse clinical scenarios. It highlights the significance of median MP while acknowledging the absence of universally applicable thresholds.

Pre- and post-diagnosis dietary patterns and overall survival in patients with epithelial ovarian cancer: a prospective cohort study

BACKGROUND

Previous studies have examined the associations between individual foods or nutrients, but few studies have considered dietary patterns associated with ovarian cancer (OC) survival.

METHODS

In a prospective cohort study, we examined the association between pre-diagnosis and post-diagnosis overall diet, including changes from pre-diagnosis to post-diagnosis, and overall survival (OS) in 560 patients with OC. Dietary intake was collected using a valid 111-item food frequency questionnaire. Principal component analysis was performed to determine the dietary patterns. Cox proportional hazard regression models were used to assess the hazard ratio (HRs) and 95% confidence interval (CIs).

RESULTS

Two dietary patterns were identified: Balanced and nutritious pattern and Energy-dense pattern. The highest tertile of the post-diagnosis Balanced and nutritious pattern scores was related to better OS compared with the lowest tertile (HR = 0.40, 95% CI = 0.17-0.95, Ptrend < 0.05). However, no significant association between pre-diagnosis and post-diagnosis Energy-dense pattern scores and OS was observed. Compared to those who had persistently high Balanced and nutritious pattern scores, patients who changed from a high score of pre-diagnosis Balanced and nutritious pattern to low post-diagnosis, as well as those who shifted from a low to a high score, both had a decreased OS (HRhigh-low vs. high-high = 1.91, 95% CI = 1.18-3.08; HRlow-high vs. high-high = 2.19, 95% CI = 1.24-3.86). Additionally, patients who changed from a high pre-diagnosis score to a low post-diagnosis score had a decreased OS compared to those with consistently low Energy-dense pattern scores (HRhigh-low vs. low-low = 1.74, 95% CI = 1.06-2.84).

CONCLUSIONS

Greater adherence to the Balanced and nutritious pattern as well as less adherence to the Energy-dense pattern from pre-diagnosis to post-diagnosis were associated with better OC survival.

Tracing impacts of prenatal exposure to bisphenol analogues on child anogenital distance development: A birth-cohort study

Prenatal exposure to bisphenol analogues (BPs) is increasingly common and may affect children's reproductive development. However, human evidence is limited and inconsistent. Based on the Shanghai-Minhang Birth Cohort Study that enrolled participants in 2012 at Minhang Maternal and Child Health Hospital in Shanghai, China, we measured BPs in maternal urine samples collected during late pregnancy and children's anogenital distance (AGD: boys, AGDAP (anus-penis), AGDAS (anus-scrotum); girls, AGDAC (anus-clitoris), AGDAF (anus-fourchette)) from birth to 48 months as an indicator of reproductive development. A total of 545 mother-child pairs were included. Boys with detected maternal bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF) tended to have increased AGDAP at 6 months, while at 12 months, BPA, BPS, and BPAF were associated with a marginal decrease in AGDAP. In girls, higher levels of BPA, BPF and BPS were associated with longer AGD at 48 months and higher risks of rapid AGD growth. Bayesian kernel machine regression models showed significant associations between BPs mixtures and AGD in both sexes, with BPF and BPS identified as major contributors. Our study revealed the lasting, sex-specific impacts of prenatal exposure to BPA and its alternatives on children's reproductive development.

Distinguishing Description, Prediction, and Causal Inference: A Primer on Improving Congruence Between Research Questions and Methods

This primer introduces the domains into which the aims of quantitative health research generally fall and provides tools to improve the methodological quality of observational clinical and population-based research articles-with a special focus on the field of neurology. Generally, research questions can be categorized into one of the following 3 data science domains: description, prediction, and causal inference. A descriptive question aims to quantify and describe the frequency and distribution of a given health condition in a certain population at or during a specific time. A predictive question aims to estimate either the probability of the presence of a given disease or health condition in an individual (diagnostic prediction) or the probability of an individual developing a disease of interest over a specified period (prognostic prediction). A causal question aims to estimate the causal effect of interest (estimand) of an exposure or intervention on an outcome in a given population. Depending on the research question, estimands could be the total causal effect, a mediated indirect effect, or effect (measure) modification by third variables, among others. Each of these domains comes with its own set of research methods, study designs, reporting guidelines, scientific language, strengths, and limitations, whereby the correct attribution of a research domain will have an impact in 3 ways: i) help authors to formulate appropriate research questions and choose and implement suitable study designs and methods; ii) allow reviewers and editors to assess studies with an increased focus on their clinical relevance, methodological advances, and novelty and quality of clinical evidence; and iii) facilitate clear communication of findings and clinical implications to the broader research community in neurology and related fields.

Exposure to different types of residential greenness during pregnancy and early childhood and attention-deficit/hyperactivity disorder diagnosis: A nested case-control study

BACKGROUND

Epidemiological studies suggest that exposure to greenness may protect children attention-deficit/hyperactivity disorder (ADHD) diagnosis. However, evidence to date is limited while no previous research has independently investigated exposure to prenatal greenness.

OBJECTIVE

We conducted a nested case-control study with data from Born in Bradford (BiB) and INfancia y Medio Ambiente (INMA) birth cohorts to investigate the association between exposure to various types of residential greenness and ADHD diagnosis, considering both pregnancy and early childhood exposure periods independently. PM2.5 was tested as a potential mediator of the association.

METHODS

Children with ADHD were identified based on a confirmed medical diagnosis. Pregnancy and early childhood exposure to residential greenness were estimated through Normalized Difference Vegetation Index (NDVI) within 300-m, urban green space and natural green space percentages within 300-m, and the linear distance to the closest green space in meters. We performed a conditional logistic regression to analyze the association between the included greenness metrics and ADHD.

RESULTS

We found no statistically significant associations between any of the pregnancy and early childhood greenness metrics and ADHD diagnosis in the BiB cohort. Further analysis on the INMA cohort found that higher urban green space percentage slightly increased the risk of ADHD diagnosis during both pregnancy (total effects: OR 1.04, 95 % CI 1.01 to 1.07, p = 0.012; direct effects: OR 1.06, 95 % CI 1.03 to 1.10, p < 0.001) and early childhood (total effects: OR 1.03, 95 % CI 1.00 to 1.07, p = 0.042; direct effects: OR 1.04, 95 % CI 1.00 to 1.07, p = 0.033). However, these associations were not supported by the sensitivity analyses.

CONCLUSIONS

This study found both null and inconsistent associations between the included greenness metrics and ADHD. Further research is warranted to elucidate the potential role of exposure to different types of greenness in ADHD diagnosis.

Association of GLIM-defined malnutrition with depressive mood in older adults undergoing rehabilitation

BACKGROUND/OBJECTIVES

Depressive mood is prevalent in geriatric patients who undergo rehabilitation. Malnutrition, which frequently coexists in this demographic group, likely affects mental health status significantly. This study examined the association between malnutrition and depressive mood at discharge in geriatric patients who were undergoing rehabilitation and identified the mediating roles of specific malnutrition components in this association.

SUBJECTS/METHODS

This prospective cohort study comprised 189 geriatric rehabilitation patients. Malnutrition was determined using the Global Leadership Initiative on Malnutrition (GLIM) criteria, and depressive mood was assessed using the Geriatric Depression Scale-15 (GDS-15). The potential mediation of the GLIM components in the relationship between malnutrition and depressive mood was evaluated using causal mediation analysis.

RESULTS

Malnutrition was positively associated with increased GDS-15 scores at both admission (p = 0.007) and discharge (p < 0.001). The severity of malnutrition corresponded with increased odds of depressive mood at discharge (moderate malnutrition: odds ratio [OR] 3.84, 95% confidence interval [CI] 1.48-9.94, p = 0.005; severe malnutrition: OR 5.11, 95% CI 1.52-15.17, p = 0.003). Notably, both muscle mass reduction (OR 1.51, 95% CI 1.01-2.27, p = 0.042) and disease burden (OR 1.37, 95% CI 1.00-1.89, p = 0.047) were identified as mediators in the association between malnutrition and depressive mood at discharge.

CONCLUSIONS

Nutritional status significantly influenced the mental health of geriatric rehabilitation patients, with muscle mass reduction and disease burden mediating this relationship. These findings emphasize the importance of a multidimensional geriatric rehabilitation approach that includes nutritional interventions.

MELK study: an observational study on human milk composition and infant health determinants during the first year of life in a Dutch cohort

INTRODUCTION

Human milk plays a crucial role in infants' nutrition and immunity, with its composition being influenced by different factors. The role of maternal diet on human milk fatty acid composition, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is well studied. Higher fish intake is associated with higher DHA levels in human milk, while fewer associations have been reported for EPA. Yet, maternal diet's impact on human milk composition for other nutrients is understudied, and variations in sampling protocols and study quality hinder definitive conclusions on its overall impact. Ethnicity may also impact milk composition, with different dietary habits intertwined with different genetic backgrounds, but also here research lacks standardised protocols. Our study aims to investigate maternal diet, ethnicity, and their association with human milk composition, along with their potential short-term associations with infant health and development, through detailed dietary assessment and by recruiting participants from diverse backgrounds. Understanding these associations could inform the development of tailored nutritional guidelines for mothers and infants, ultimately promoting optimal health and well-being for both. The study design, with its strict sampling procedure, can guide and inspire future studies.

METHODS AND ANALYSIS

We will conduct an observational study involving 120 healthy mothers from three ethnic backgrounds (Chinese, Caucasian and Turkish), exclusively breastfeeding their 2-month-old infants. We will collect human milk samples at two time points and assess maternal dietary intake over 4 days. Additionally, we will collect data on various maternal and child characteristics, including maternal stress, socioeconomic status and health, and infant feeding, sleeping, crying, gastrointestinal health and developmental status.

ETHICS AND DISSEMINATION

The study has been approved by the Medical Ethical Committee Oost-Nederland (NL79447.091.21), and all participants provided written informed consent before entering the study. Findings will be widely disseminated at international conferences and meetings including the annual Nutrition & Growth conference, ESPGHAN, and through publication in scientific peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN registry (ISRCTN35735283).

Inconsistent consistency: evaluating the well-defined intervention assumption in applied epidemiological research

BACKGROUND

According to textbook guidance, satisfying the well-defined intervention assumption is key for estimating causal effects. However, no studies have systematically evaluated how the assumption is addressed in research. Thus, we reviewed how researchers using g-methods or targeted maximum likelihood estimation (TMLE) interpreted and addressed the well-defined intervention assumption in epidemiological studies.

METHODS

We reviewed observational epidemiological studies that used g-methods or TMLE, were published from 2000-21 in epidemiology journals with the six highest 2020 impact factors and met additional criteria. Among other factors, reviewers assessed if authors of included studies aimed to estimate the effects of hypothetical interventions. Then, among such studies, reviewers assessed whether authors discussed key causal-inference assumptions (e.g. consistency or treatment variation irrelevance), how they interpreted their findings and if they specified well-defined interventions.

RESULTS

Just 20% (29/146) of studies aimed to estimate the effects of hypothetical interventions. Of such intervention-effect studies, almost none (1/29) stated 'how' the exposure would be intervened upon; among those that did not state a 'how', the 'how' mattered for consistency (i.e., for treatment variation irrelevance) in 64% of studies (18/28). Moreover, whereas 79% (23/29) of intervention-effect studies mentioned consistency, just 45% (13/29) interpreted findings as corresponding to the effects of hypothetical interventions. Finally, reviewers determined that just 38% (11/29) of intervention-effect studies had well-defined interventions.

CONCLUSIONS

We found substantial deviations between guidelines regarding meeting the well-defined intervention assumption and researchers' application of the guidelines, with authors of intervention-effect studies rarely critically examining the assumption's validity, let alone specifying well-defined interventions.

Prenatal metals and offspring cognitive development: Insights from a large-scale placental bioassay study

The developing foetus is particularly sensitive to neurotoxic metals. The placenta is considered an ideal tissue for biomonitoring prenatal cumulative metal exposure. Based on the Ma'anshan Birth Cohort study (MABC) in China, this study investigated associations of non-essential metals and essential metals in placenta, including arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), cobalt (Co), selenium (Se) and zinc (Zn), with cognitive development in children among 1586 mother-child pairs. Also, we explored potential interactions between the metals and modifying role of the sex. Children's cognitive development was tested at preschool age using the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV). Analyses used multiple linear regression, Bayesian kernel machine regression (BKMR), the quantile g-computation (Qgcomp), interaction and marginal effects models, and restricted cubic spline in R and STATA. In this study, the geometric means [GMs (SD)] for placental metal concentrations were 8.10 (7.54) ng/g for As, 32.32 (29.20) ng/g for Cd, 11.89 (13.33) ng/g for Hg, 32.21 (28.24) ng/g for Pb, 15.05 (8.91) ng/g for Co, 508.82 (192.35) ng/g for Se, 18481.60 (14030.61) ng/g for Zn. In individual models, placental As levels were negatively associated with the Fluent Reasoning Index (FRI) in the overall sample. Cd levels were negatively associated with the full-scale intelligence quotient (FSIQ), the Verbal Comprehension Index (VCI) and the Visual Spatial Index (VSI). The four metal mixture (As, Cd, Hg and Pb) was negatively associated with FSIQ, VCI, VSI and FRI. Placental Cd and As were the largest contributors to the negative mixture association on the FSIQ. The negative associations of placental As, Cd and Hg with FSIQ in children were gradually attenuated with increasing Zn and Se. After stratifying by sex, the individual and mixture associations between elevated placental non-essential metal exposures and reduced cognitive scores were significant only in boys. Zn and Se were the major contributors to the positive mixture associations on the FSIQ. In summary, prenatal exposure to As, Cd and Hg has sex-specific adverse associations on children's cognitive development. A more accurate assessment of the necessity of prenatal supplementation of micronutrients including Zn and Se is needed.

Bayesian network modeling of statistical dependency within cognitive domains and clinical dementia severity ratings for Western and Indian cohorts

BACKGROUND

Dementia is studied rigorously in the current times, to assess the potential factors that contribute towards its progression, such as demographic factors, geographical background as well as to understand its impact on essential life skills. Alzheimer's disease, the most common form of dementia, is a major focus due to its prevalence and lack of curative treatments.

OBJECTIVE

We aim to study dementia progression across two geographically distinct populations, by analyzing Clinical Dementia Rating (CDR) scores and its domain-specific components, which reflect the decline in essential life skills. This analysis may support clinicians in designing targeted interventions.

METHODS

This study investigates the statistical dependencies between the CDR and its six defining domain scores across two distinct aging datasets: the Alzheimer's Disease Neuroimaging Initiative (ADNI) and the Longitudinal Aging Study of India (LASI). We analyzed the dependencies among domain scores and their influence on the global CDR in both datasets using data-driven directed acyclic graphs, within Bayesian network models.

RESULTS

Distinct notable similarities and differences in the associations and the edge strengths between the Western and Indian populations were identified. Memory showed similar prominence in contributing towards global CDR, while the incoming edges on memory domain reduced in LASI over ADNI, specifically from the domains, Home and hobbies, and Community affairs.

CONCLUSIONS

The analysis highlights a stronger dependency of CDR scores on memory functions in both datasets. The results overall elucidate population-specific differences and similarities in dementia progression across diverse demographic contexts.

Association of Antioxidant Diet with Risk of Hyperemesis Gravidarum Among Chinese Pregnant Women: A Population-Based Cross-Sectional Study

(1) Background: Oxidative stress plays a pivotal role in the pathophysiologic of hyperemesis gravidarum (HG). Epidemiological studies have explored the associations of specific antioxidant foods and nutrients with HG. However, evidence regarding the relationship between an antioxidant-rich diet and the risk of HG remains limited. The objective of this research was to explore the relationship between antioxidant-rich diet and HG. (2) Methods: This was a population-based cross-sectional study. A total of 2980 pregnant women were included in our population. A composite dietary antioxidant index (CDAI) was calculated by summing the standardized intakes of vitamins A, C, and E, selenium, zinc, and total carotene. A dietary antioxidant potential score (DAPS) was derived using reduced rank regression. Binary logistic regression models were employed to analyze the associations of CDAI and DAPS with risk of HG. (3) Results: In total, 241 (8.09%) cases of HG were identified in this study. After adjusting for potential confounders, including age, socioeconomic status, ethnicity, physical activity, current smoking status, current alcohol consumption, pre-pregnancy body mass index, nutritional supplement usage, total energy intake, gestational week, menstruation regularity, family history of HG, primigravida status, and quality of life during pregnancy, ORs (95% CIs) of HG in the highest tertiles were 0.31 (0.21-0.47) for CDAI and 0.41 (0.28-0.57) for DAPS when comparing lowest tertiles (all p-trend < 0.001). Such associations remained robust across multiple sensitivity analyses and subgroup analyses. (4) Conclusions: Higher CDAI and DAPS, indicative of greater adherence to an antioxidant-rich diet, were associated with a lower risk of HG. This finding underscores the crucial role of consuming antioxidant-rich foods in the prevention of HG.

Modeling Upper Limb Rehabilitation-Induced Recovery After Stroke: The Role of Attention as a Clinical Confounder

OBJECTIVE

People who have survived stroke may have motor and cognitive impairments. High dose of motor rehabilitation was found to provide clinically relevant improvement to upper limb (UL) motor function. Besides, mounting evidence suggests that clinical, neural, and neurophysiological features are associated with spontaneous recovery. However, the association between these features and rehabilitation-induced, rather than spontaneous, recovery has never been fully investigated. The objective was to explore the association between rehabilitation dose and UL motor outcome after stroke, as well as to identify which variables can be considered potential candidate predictors of motor recovery.

METHODS

People who survived stroke were assessed before and after a period of rehabilitation using motor, cognitive, neuroanatomical, and neurophysiological measures. We investigated the association between dose of rehabilitation and UL response (ie, Fugl-Meyer Assessment for upper extremity [FMA-UE]), using ordinary least squares regression as the primary analysis. To obtain unbiased estimates, adjusting covariates were selected using a directed acyclic graph.

RESULTS

Baseline FMA-UE was the only factor associated with motor recovery (b = 0.99; 95% CI = 0.83 to 1.15 points). Attention emerged as a confounder of the association between rehabilitation and final FMA-UE (b = 5.5; 95% CI = -0.8 to 11.9 points), influencing both rehabilitation and UL response.

CONCLUSION

Preserved attention in people who have survived stroke might lead to greater UL motor recovery, albeit estimates have high levels of variability. Moreover, the increase in the dose of rehabilitation can lead to 5.5 points improvement on the FMA-UE, a nonsignificant but potentially meaningful finding. The approach described here discloses a new framework for investigating the effect of rehabilitation treatment as a potential driver of recovery.

IMPACT

Attentional resources could play a key role in UL motor recovery. There is a potential association between amount of UL recovery and dose of rehabilitation delivered, needing further exploration. Preserved attention and rehabilitation dose are candidate predictors of UL motor recovery.

Dietary Acid Load and Human Health: A Systematic Review and Meta-analysis of Observational Studies

CONTEXT

Dietary acid load (DAL) plays an important role in different aspects of human health.

OBJECTIVE

The aim of this meta-analysis was to systematically synthesize the observational evidence reporting on the associations between the DAL (represented by a potential renal acid load [PRAL] and net endogenous acid production [NEAP]) and a range of health outcomes.

DATA SOURCES

A systematic search of Medline (via PubMed), EMBASE, Scopus, and Web of Science was performed to identify eligible studies.

DATA EXTRACTION

Study screening and risk-of-bias assessment were conducted by 2 independent reviewers.

DATA ANALYSIS

The credibility of each outcome was graded based on predefined criteria: pooled effect size with corresponding 95% CI, 95% prediction interval, heterogeneity, small-study effect, and excess significance bias. In total, 118 observational studies (case-control [n = 22], cross-sectional [n = 65], and cohort [n = 31]) on 38 outcomes were included, incorporating a total population of 1 014 081 participants. Overall, 21/37 and 20/38 of the outcomes reported statistically significant effect sizes for PRAL and NEAP, respectively. The credibility of the evidence for PRAL was rated convincing (class I) for type 2 diabetes (T2D), and as highly suggestive evidence (class II) for overall cancer and systolic blood pressure. By assessing the credibility of the evidence for NEAP, T2D and overall cancer presented convincing evidence (class I) and breast cancer presented highly suggestive evidence (class II). The remaining outcomes presented class III (suggestive) or lower evidence (weak or no association).

CONCLUSION

The higher acid-forming potential of diet was associated with a higher risk of T2D and overall cancer. Since this meta-analysis included observational studies and some of the associations were graded as weak, caution should be exercised in interpreting these associations. Further cohort studies are required with consideration of other factors that can cause biases.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022336050.

Association between plasma perfluoroalkyl substances and high-grade serous ovarian cancer overall survival: A nested case-control study

BACKGROUND

Although evidence suggests that perfluoroalkyl and polyfluoroalkyl substances (PFASs) are positively correlated to several disease risks, no studies have proven if plasma PFASs are related to ovarian cancer survival.

OBJECTIVE

To explore the association between plasma PFASs and high-grade serous ovarian cancer (HGSOC) overall survival (OS) in the population who did not smoke.

METHODS

We conducted a nested case-control study within the Ovarian Cancer Follow-Up Study, matching 159 dead patients and 159 survival ones based on body mass index, sample date, and age at diagnosis. Nine plasma PFASs were extracted by solid phase extraction and measured using a liquid chromatography system coupled with tandem mass spectrometry. Baseline plasma concentrations of perfluorinated carboxylic acids (PFCAs) [perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroheptanoic acid (PFHpA)] and perfluorinated sulfonic acids (PFSAs) [perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS)] were calculated. Odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) were calculated via conditional logistic regression models. To elucidate the combined effects, Bayesian kernel machine (BKMR), and regression quantile g-computation (QGC) models were utilized.

RESULT

In full-adjusted model, significant differences were observed between HGSOC survival and perfluorobutane sulfonic acid, PFHpA, PFHxS, PFOS, PFCA, and PFSA. ORs and 95 %CIs were 2.74 (1.41-5.31), 1.97 (1.03-3.76), 2.13 (1.15-3.95), 2.28 (1.16-4.47), 3.74 (1.78-7.85), and 2.56 (1.31-5.01), respectively for the highest tertile compared with the lowest tertile. The QGC and BKMR models indicated that elevated concentrations of PFAS mixtures were associated with poor OS in HGSOC.

CONCLUSIONS

Both individual and mixed plasma PFASs may relate to poor OS of HGSOC. Further research is necessary to establish causality, and it is recommended to reinforce environmental risk mitigation strategies to minimize PFAS exposure.

Rethinking animal attrition in preclinical research: Expressing causal mechanisms of selection bias using directed acyclic graphs

Animal attrition in preclinical experiments can introduce bias in the estimation of causal treatment effects, as the treatment-outcome association in surviving animals may not represent the causal effect of interest. This can compromise the internal validity of the study despite randomization at the outset. Directed Acyclic Graphs (DAGs) are useful tools to transparently visualize assumptions about the causal structure underlying observed data. By illustrating relationships between relevant variables, DAGs enable the detection of even less intuitive biases, and can thereby inform strategies for their mitigation. In this study, we present an illustrative causal model for preclinical stroke research, in which animal attrition induces a specific type of selection bias (i.e., collider stratification bias) due to the interplay of animal welfare, initial disease severity and negative side effects of treatment. Even when the treatment had no causal effect, our simulations revealed substantial bias across different scenarios. We show how researchers can detect and potentially mitigate this bias in the analysis phase, even when only data from surviving animals are available, if knowledge of the underlying causal process that gave rise to the data is available. Collider stratification bias should be a concern in preclinical animal studies with severe side effects and high post-randomization attrition.

Is inverse probability of censoring weighting a safer choice than per-protocol analysis in clinical trials?

Deviation from the treatment strategy under investigation occurs in many clinical trials. We term this intervention deviation. Per-protocol analyses are widely adopted to estimate a hypothetical estimand without the occurrence of intervention deviation. Per-protocol by censoring is prone to selection bias when intervention deviation is associated with time-varying confounders that also influence counterfactual outcomes. This can be corrected by inverse probability of censoring weighting, which gives extra weight to uncensored individuals who had similar prognostic characteristics to censored individuals. Such weights are computed by modelling selected covariates. Inverse probability of censoring weighting relies on the no unmeasured confounding assumption whose plausibility is not statistically testable. Suboptimal implementation of inverse probability of censoring weighting which violates the assumption will lead to bias. In a simulation study, we evaluated the performance of per-protocol and inverse probability of censoring weighting with different implementations to explore whether inverse probability of censoring weighting is a safe alternative to per-protocol. Scenarios were designed to vary intervention deviation in one or both arms with different prevalences, correlation between two confounders, effect of each confounder, and sample size. Results show that inverse probability of censoring weighting with different combinations of covariates outperforms per-protocol in most scenarios, except for an unusual case where selection bias caused by two confounders is in two directions, and 'cancels' out.

Deforestation and predator species richness as potential environmental drivers for roadkill of wild water deer in South Korea

Introduction

The roadkill incidence of Korean water deer (Hydropotes inermis argyropus) has become a nationwide concern in recent years because of its contribution to biodiversity loss. Various environmental risk factors for the occurrence of roadkill events were found. However, there is a gap in observational studies focusing on the effects of deforestation and predator species richness on the roadkill, despite their plausible mechanisms. This study aimed to investigate the associations between water deer roadkill events and environmental risk factors in South Korea.

Methods

We analyzed 1,986 roadkill events of water deer recorded on highway routes managed by the Korean National Transport Center from 2019 to 2021 as an outcome variable, and the values of environmental factors collated as explanatory variables. Multivariate logistic regression models were used to investigate these associations.

Results

This study highlighted two main explanatory variables: predator species richness and deforestation, and the results indicate that higher deforestation level was associated with higher odds of the roadkill incidence, with an odds ratio of 1.15 [95% confidence interval (CI) = 1.07-1.25] from the ordinary model and 1.11 (95% credible interval = 1.03-1.21) from the spatial regression model. Conversely, predator species richness is negatively associated with the roadkill events, with an odds ratio of 0.75 (95% confidence interval = 0.69 to 0.80) from the ordinary regression model and 0.76 (95% credible interval = 0.66-0.86) from the spatial regression model.

Conclusion

These findings suggest that conservational effort, such as preventing wildlife diversity and mitigating deforestation could reduce the incidence of water deer roadkill events.

Association of pre- and post-diagnosis dietary total antioxidant capacity (TAC) and composite dietary antioxidant index (CDAI) with overall survival in patients with ovarian cancer: a prospective cohort study

BACKGROUND

The evidence on the relationship of dietary antioxidant nutrients with the survival of ovarian cancer (OC) remains scarce.

OBJECTIVE

This study aimed to investigate these associations in a prospective cohort of Chinese patients with OC.

METHODS

In this prospective cohort study, patients with epithelial OC completed a food frequency questionnaire at diagnosis and 12 months post-diagnosis, and were followed from 2015 to 2023. Dietary total antioxidant capacity (TAC) and composite dietary antioxidant index (CDAI) were calculated based on specific antioxidant nutrients. We examined the associations of pre-diagnosis, post-diagnosis, and changes from pre-diagnosis to post-diagnosis in TAC, CDAI, and representative antioxidant nutrients with overall survival (OS) among patients with OC. Multivariable Cox proportional-hazards models were applied to calculate the hazard ratios (HR) and 95% confidence intervals (CI). Dose-response relationships were evaluated by restricted cubic splines.

RESULTS

Among the total 560 patients with OC, there were 211 (37.68%) deaths during a median follow-up of 44.40 (interquartile range: 26.97-61.37) months. High pre-diagnosis TAC (HR = 0.58; 95% CI 0.38-0.8) and vitamin C intake (HRT3 vs. T1 = 0.36; 95% CI 0.21-0.61), and post-diagnosis TAC (HR = 0.57; 95% CI 0.37-0.8), CDAI (HR = 0.57; 95% CI 0.33-0.9), and β-carotene intake (HRT3 vs. T1 = 0.55; 95% CI 0.32-0.97) were significantly associated with improved OS. Compared to patients with constantly low pre- and post-diagnosis TAC and CDAI, those with consistently higher TAC (HRMedium-Medium vs. Low-Low = 0.53; 95% CI 0.29-0.97; HRHigh-High vs. Low-Low = 0.40; 95% CI 0.16-0.94) and CDAI (HRHigh-High vs. Low-Low = 0.33; 95% CI 0.12-0.88) experienced better OS.

CONCLUSION

High pre- and post-diagnosis TAC, and post-diagnosis CDAI were associated with improved OC survival, suggesting that consistent high-intake of antioxidant-rich food may be beneficial for the prognosis of OC.

Physical Activity and Falls From Midlife: Patterns and Bidirectional Associations

INTRODUCTION

The relationship between physical activity behavior and subsequent falls in adults from midlife to older age is unclear. Falls and fall-related injuries could lessen physical activity participation. This study examined patterns and bidirectional associations between physical activity and falls from midlife to older age.

METHODS

In the Australian Longitudinal Study on Women's Health, women born 1946-1951 (n=11,759, mean age: 56 years at baseline in 2004) self-reported weekly physical activity amounts (0, 1-<150, 150-<300, ≥300 minutes/week) and noninjurious and injurious falls every 3 years between 2004 survey and 2019 survey. Bidirectional prospective 3-year associations between physical activity and falls were examined using generalized estimating equations to estimate ORs and 95% CIs, adjusting for directed acyclic graph-informed covariates. Analyses were conducted in 2023.

RESULTS

Participation in any amount of physical activity was associated with a reduced risk of injurious falls (OR1-<150 min=0.87; 95% CI=0.80, 0.96; OR150-<300 min=0.87; 95% CI= 0.79, 0.96; OR≥300 min=0.85; 95% CI=0.78, 0.93) in the next 3 years, compared with women with no physical activity. Women who reported noninjurious falls had lower odds of undertaking ≥300 minutes/week of physical activity 3 years later (OR=0.84; 95% CI=0.77, 0.92), compared with women without falls. Women who reported injurious falls had lower odds of subsequently undertaking various amounts of physical activity (OR=0.83, 95% CI=0.75, 0.91 for 1-<150; OR=0.82, 95% CI=0.74, 0.90 for 150-<300; OR=0.83, 95% CI=0.76, 0.90 for ≥300 minutes/week).

CONCLUSIONS

The prospective bidirectional association between physical activity and falls supports addressing falls by promoting activity and highlighting the impact of injurious falls on reduced physical activity participation.

An updated systematic review with meta-analysis and meta-regression of the factors associated with human visceral leishmaniasis in the Americas

BACKGROUND

Human visceral leishmaniasis (VL) is a systemic disease with high case-fatality rates and a widespread distribution. Continuous evaluation of the risk factors for VL is essential to ensure the effective implementation of prevention and control measures. The present study reviews the factors associated with VL in the Americas.

METHODS

This systematic review updates a previous 2013 report by including cross-sectional, cohort and case-control studies published between July 2011 and April 2024. Associations between VL and risk factors were analyzed using random-effects meta-analysis, subgroup analysis, and meta-regression models. Studies were classified according to level of evidence using the GRADE approach and the evolution in the quality of investigations was assessed.

RESULTS

Forty-six studies were included in the review and 21 variables were evaluated in the meta-analyses. Combination of all study types revealed that men had greater chances of VL than women, but the association was strong and significant only in case-control studies. Although higher chances of VL in children and in households with dogs or chickens/other fowl were identified in case-control studies, an inverse association was observed in cross-sectional and cohort studies. Higher chances of VL were associated with poor economic/living conditions, individuals living in domiciles with backyards or with seropositive dogs, and individuals with prior contact with infected household members/relatives/neighbors. The level of evidence for associations of VL with sex and age was classified as moderate whilst that for all other associations was either low or very low. The methodological quality of recent studies showed a positive progression but shortcomings were still evident regarding selection criteria and methods of data analysis.

CONCLUSION

While there is a higher incidence of symptomatic VL among men and children, the likelihood of infection is similar between the groups. There is insufficient evidence to support the claim that the presence of dogs or fowl at the domicile increases the chances of VL. However, socioeconomic and living conditions, as well as previous occurrence of human and canine VL, are influential factors. Future research should be conducted with greater statistical power and using molecular diagnostic techniques, preferably involving cohort studies in diverse Latin American countries.

Evaluation of the association between thyroid-stimulating hormone with handgrip strength and dynapenia in euthyroid postmenopausal women

OBJECTIVE

To examine the association between serum thyroid-stimulating hormone (TSH) levels with handgrip strength (HGS) and dynapenia in euthyroid postmenopausal women.

METHODS

This was an exploratory cross-sectional study among 385 participants from the Department of Obstetrics, Gynecology, and Reproduction of the Dexeus Women's University Hospital, Barcelona, Spain. Age, age at menopause, adiposity, alcohol consumption, body mass index (BMI), and smoking status were recorded. TSH was determined by electrochemiluminescence immunoassay. HGS was measured using a digital dynamometer, and physical activity was assessed by the International Physical Activity Questionnaire. Dynapenia was considered when HGS was <20 kg. A directed acyclic graph was designed to identify confounding variables. Multivariable linear and logistic regression models were adjusted by age, age at menopause, adiposity, BMI, glomerular filtration rate, glycated hemoglobin, physical activity, and smoking status.

RESULTS

Multivariable linear regression model showed that age ( β = -0.22; 95% CI, -0.28 to -0.16), adiposity ( β = -0.15; 95% CI, -0.22 to -0.07), BMI ( β = 0.15; 95% CI, 0.04-0.25), glomerular filtration rate ( β = -0.04; 95% CI, -0.07 to -0.01), and physical activity ( β = 0.79; 95% CI, 0.07-1.5) were significantly associated with HGS. Instead, serum TSH levels were not significantly associated ( β = 0.21; 95% CI, -0.10 to 0.51). Multivariable logistic regression model showed that dynapenia was associated with age (OR, 1.20; 95% CI, 1.12-1.31) and glomerular filtration rate (OR, 1.03; 95% CI, 1.00-1.05). No significant association between TSH and dynapenia was observed (OR, 0.98; 95% CI, 0.78-1.23).

CONCLUSIONS

In this study of postmenopausal women, normal TSH levels were not associated with low HGS or dynapenia.

Fluid intake and recurrence and progression risk of patients with non-muscle-invasive bladder cancer

OBJECTIVES

To evaluate the association of pre- and post-diagnosis fluid intake with non-muscle-invasive bladder cancer (NMIBC) recurrence and progression risk.

PATIENTS AND METHODS

Data were used from the multicentre prospective cohort study UroLife. Participants reported pre-diagnosis fluid intake at 6 weeks (food frequency questionnaire [FFQ]) (n = 1322) and post-diagnosis fluid intake at 3 and 15 months (FFQ and 4-day 24-h fluid diaries) (n = 1275) after diagnosis. Multivariable proportional hazard regression models were used to obtain hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of fluid intake with risk of first and multiple recurrence(s) and progression.

RESULTS

During a median overall follow-up of 4.6 years, 474 patients had one or more recurrence and 142 had progression. A higher first recurrence risk was observed for patients with the highest pre-diagnosis fluid intakes (≥2300 vs 1500-1900 mL/day: HR 1.38, 95% CI 1.07-1.79), but not for those with the highest post-diagnosis fluid intakes. HRs were similar for multiple recurrence risk. For progression, each 150 mL/day increase in both pre- and post-diagnosis fluid intake was consistently associated with an increased risk (post-diagnosis [3 months] FFQ-based: HR 1.05, 95% CI 1.01-1.09 and diary-based: HR 1.04, 95% CI 0.99-1.09).

CONCLUSION

High fluid intakes may be associated with higher NMIBC recurrence and especially progression risk. These findings lack a clear explanation but may be related to extensive expansion of the bladder wall or urinary symptoms. Further research is warranted. Meanwhile, these findings do not support recommending high(er) fluid intakes to patients with NMIBC to decrease their recurrence or progression risk.

Unbound bilirubin and risk of severe neurodevelopmental impairment in extremely low birthweight newborns

BACKGROUND

Unbound bilirubin (UB) was measured on day 5 ± 1 in 1101 ELBW newborns in the Aggressive vs Conservative Phototherapy randomized controlled trial. We accessed this dataset to quantify the UB-mediated risk of severe neurodevelopmental impairment (sNDI) in extremely low birthweight (ELBW) newborns.

METHODS

UB levels were standardized within laboratories as z-score percentiles. A dichotomous UB exposure variable was based on sharply increased risk of sNDI at the 85th percentile (UBz>85th). Targeted maximum likelihood estimation with ensemble machine learning (TMLE + ML) and logistic regression (LR) were used to estimate sNDI risk attributable to UBz>85th.

RESULTS

UB - total bilirubin correlation was poor: R2 0.24, 95% CI: 0.19, 0.30. The UB level corresponding to the UBz>85th cut-point in this cohort was estimated to be between 0.56 and 0.79 µg/dL. In 825 survivors with known sNDI status the crude risk difference (RD) associated with UBz>85th was 19.5%. With TMLE + ML, the RD was 14.4% (95% CI: 5.7%, 23.1%) corresponding to a number need to harm (NNH) of 7 (95% CI: 4, 18). LR results were similar: RD 12.4% (95% CI: 4.7%, 20.1%), NNH 8 (95% CI: 5, 21).

CONCLUSIONS

Exposure to UBz>85th was associated with a large increase in risk of sNDI in ELBW newborns.

IMPACT

Accessing the only large dataset with measures of unbound bilirubin (UB) and neurodevelopmental outcomes in extremely low birthweight (ELBW) newborns we found poor correlation between UB and total bilirubin (TB). The risk of severe neurodevelopmental impairment (sNDI) associated with UB rose non-linearly with an inflection point at UB z-score 85th percentile (UBz>85th), increasing the risk of sNDI by an estimated 14% (number need to harm: 7). The current incidence of exposure to harmful UB levels in very premature newborns is unlikely to be rare. TB levels provide a false sense of security to clinicians caring for very premature newborns.

Estimating the Effect of Adhering to the Recommendations of the 2019 Canada's Food Guide on Health Outcomes in Older Adults: Protocol for a Target Trial Emulation

BACKGROUND

The 2019 Canada's Food Guide provides universal recommendations to individuals aged ≥2 years. However, the extent to which these recommendations are appropriate for older adults is unknown. Although ideal, conducting a large randomized controlled trial is unrealistic in the short term. An alternative is the target trial emulation framework for causal inference, a novel approach to improve the analysis of observational data.

OBJECTIVE

This study aims to describe the protocol for a target trial emulation in older adults, with an emphasis on key aspects of a hypothetical sustained diet and physical activity intervention.

METHODS

To emulate the target trial, nonexperimental data from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge; N=1753 adults aged ≥67 years) will be used. NuAge includes 4 yearly measurements of dietary intakes, covariates, and outcomes. The per-protocol causal contrast will be the primary causal contrast of interest to account for nonadherence. The sustained intervention strategy will be modeled using the parametric g-formula. In the hypothetical trial, participants will be instructed to meet sex-specific minimal intakes for vegetables and fruits, whole grains, animal- and plant-based protein foods, milk and plant-based beverages, and unsaturated fats. The eligibility criteria, follow-up, intervention, outcomes, and causal contrast in the emulation will closely align with those of the target trial, with only minor modifications. We will attempt to emulate the randomization of treatment by adjusting for baseline covariates and prebaseline dietary habits.

RESULTS

Data collection for NuAge was completed in June 2008. For this study, the main analysis was started in May 2024. Submission of the manuscript is expected by February 2025.

CONCLUSIONS

Emulating a target trial will provide the first evidence of the adequacy of the 2019 Canada's Food Guide recommendations for older adults in relation to health outcomes.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/65182.

Directed Acyclic Graphs in Decision-Analytic Modeling: Bridging Causal Inference and Effective Model Design in Medical Decision Making

HIGHLIGHTS

Our commentary proposes the application of directed acyclic graphs (DAGs) in the design of decision-analytic models, offering researchers a valuable and structured tool to enhance transparency and accuracy by bridging the gap between causal inference and model design in medical decision making.The practical examples in this article showcase the transformative effect DAGs can have on model structure, parameter selection, and the resulting conclusions on effectiveness and cost-effectiveness.This methodological article invites a broader conversation on decision-modeling choices grounded in causal assumptions.

Incidence of chronic pelvic pain after childbirth and its causal association with C-section

ABSTRACT

This study aimed to report the incidence of chronic pelvic pain in women 12 to 24 months postpartum, to identify the independently associated factors, and to conduct a causal inference with C-section as the exposure. This was a cross-sectional study nested within 2 distinct prospective cohorts from 2 Brazilian cities. Chronic pelvic pain was the dependent variable. Independent variables were collected. Fisher exact test or Pearson χ2 test and t test or Wilcoxon rank-sum test were performed as appropriate, with P-values adjusted. Data were assumed to be missing at random, and multivariate imputation by chained equations was performed. Sensitivity analysis was conducted using complete cases. Multicollinearity was assessed by computing the variance inflation factor. Binomial logistic regression was used to obtain an interpretable model. Odds ratios and 95% confidence intervals were used as measurements. A directed acyclic graph was used for causal inference. A total of 2160 women were included. The incidence of chronic pelvic pain was 12.7%. C-sections doubled the odds of developing chronic pelvic pain (CPP). Additional factors associated with increased odds included city of birth, feelings of discrimination, severe symptoms of anxiety, dissatisfaction with the care received during childbirth, and mental suffering. Women who underwent C-sections had a 6.1% higher incidence of CPP compared to those who did not undergo the procedure. The incidence of CPP postpartum is high, and there is a potential causal effect of C-sections. City of birth, discrimination, anxiety, dissatisfaction with the care, and mental suffering were also associated with an increased odds.

Beyond LDL cholesterol: remnant cholesterol is associated with cardiometabolic risk factors in children

BACKGROUND

Recent evidence from both randomized controlled trials and cohort studies in adults suggests that plasma remnant cholesterol (RC) levels predict cardiovascular disease. In children, studies are scarce, although high levels of RC might represent a marker of early atherosclerotic damage. Thus, the aim of this study was to explore the cardiometabolic risk associated with RC, which extends beyond low-density lipoprotein cholesterol (LDL-c) in children.

METHODS

Cardiometabolic risk factors (plasma insulin levels, homeostatic model assessment for insulin resistance, mean arterial blood pressure (MAP), waist circumference (WC), and cardiorespiratory fitness (CRF)) were examined in 3417 Spanish schoolchildren aged 8-11 years. The children were categorized into four subgroups (low vs. high) based on the cutoff of ≥ 110 mg/dL for LDL-c and of ≥ 15 mg/dL for RC to define higher levels, and ANCOVA models were applied to assess the role of both lipid parameters in cardiometabolic risk. Additionally, multilevel mixed-effects generalized linear regression models were used to assess the associations of RC or LDL-c with cardiometabolic risk factors and to examine whether the associations between RC and these factors varied in children with low or high LDL-c levels.

RESULTS

Children in the high-RC subgroups, specifically those with low LDL-c/high RC and high LDL-c/high RC, presented significantly greater insulin levels and WC than did their peers in the low-RC subgroups. RC was more strongly associated with cardiometabolic risk factors than LDL-c (insulin β = 2.073/ - 0.026; HOMA-IR β = 0.451/ - 0.002; MAP β = 1.214/0.300; WC β = 2.842/1.058; and CRF β = - 0.316/ - 0.194 for RC and LDL-c, respectively). Furthermore, RC exhibited associations even in children with low LDL-c levels: insulin (β = 2.305; p < 0.001), HOMA-IR (β = 0.499; p < 0.001), MAP (β = 1.397, p < 0.001), WC (β = 2.842; p < 0.001), and CRF (β = - 0.367; p < 0.001).

CONCLUSIONS

The associations between RC and cardiometabolic risk factors were stronger than those between LDL-c and cardiometabolic risk, extending its significance even in children with low LDL-c levels. These findings may be clinically useful for cardiovascular risk stratification and for guiding future interventions in children, although they should be confirmed by longitudinal studies.

Long-term exposure to fine particulate matter constituents and the prognosis of oral cancer patients: A prospective study in Southeastern China

Evidence on the association of long-term exposure to fine particular matter (PM2.5) and its chemical constituents with the prognosis of oral cancer patients is limited. We identified 1673 oral cancer patients from 2011 to 2021 in Fujian, China. We evaluated annual average concentrations of PM2.5 and constituents, including nitrate, sulfate, ammonium, black carbon (BC), and organic matter (OM), using bilinear interpolation based on the patients' residential address. Cox proportional hazard models were used to calculate the hazard ratio (HR) and 95 % confidence interval. We used counterfactual analyses to evaluate the population attributable fractions (PAF). During a median follow-up duration of 3.58 years, 484 (28.93 %) died. For per-SD increase in PM2.5, nitrate, sulfate, ammonium, OM, and BC, the adjusted HRs were 1.18, 1.16, 1.18, 1.19, 1.17, and 1.20 for all-cause mortality, and 1.26, 1.22, 1.27, 1.28, 1.24, and 1.29 for oral cancer-specific mortality, respectively. The corresponding PAFs of PM2.5, nitrate, sulfate, ammonium, OM, and BC were 25.43 %, 24.19 %, 25.73 %, 25.78 %, 25.28 %, and 26.59 % for all-cause mortality, and 26.61 %, 24.19 %, 27.15 %, 27.01 %, 26.19 %, and 28.41 % for oral cancer-specific mortality, respectively. Our study showed that long-term exposure to PM2.5 and constituents might be an important risk factor for mortality among oral cancer patients.

Chronic low back pain causal risk factors identified by Mendelian randomization: a cross-sectional cohort analysis

BACKGROUND CONTEXT

There are a number of risk factors- from biological, psychological, and social domains- for nonspecific chronic low back pain (cLBP). Many cLBP treatments target risk factors on the assumption that the targeted factor is not just associated with cLBP but is also a cause (i.e., a causal risk factor). In most cases this is a strong assumption, primarily due to the possibility of confounding variables. False assumptions about the causal relationships between risk factors and cLBP likely contribute to the generally marginal results from cLBP treatments.

PURPOSE

The objectives of this study were to a) using rigorous confounding control compare associations between modifiable causal risk factors identified by Mendelian randomization (MR) studies with associations in a cLBP population and b) estimate the association of these risk factors with cLBP outcomes.

STUDY DESIGN/SETTING

Cross sectional analysis of a longitudinal, online, observational study.

PATIENT SAMPLE

1,376 participants in BACKHOME, a longitudinal observational e-Cohort of U.S. adults with cLBP that is part of the NIH Back Pain Consortium (BACPAC) Research Program.

OUTCOME MEASURES

Pain, Enjoyment of Life, and General Activity (PEG) Scale.

METHODS

Five risk factors were selected based on evidence from MR randomization studies: sleep disturbance, depression, BMI, alcohol use, and smoking status. Confounders were identified using the ESC-DAG approach, a rigorous method for building directed acyclic graphs based on causal criteria. Strong evidence for confounding was found for age, female sex, education, relationship status, financial strain, anxiety, fear avoidance and catastrophizing. These variables were used to determine the adjustment sets for the primary analysis. Potential confounders with weaker evidence were used for a sensitivity analysis.

RESULTS

Participants had the following characteristics: age 54.9±14.4 years, 67.4% female, 60% never smokers, 29.9% overweight, 39.5% obese, PROMIS sleep disturbance T-score 54.8±8.0, PROMIS depression T-score 52.6±10.1, Fear-avoidance Beliefs Questionnaire 11.6±5.9, Patient Catastrophizing Scale 4.5±2.6, PEG 4.4±2.2. In the adjusted models, alcohol use, sleep disturbance, depression, and obesity were associated with PEG, after adjusting for confounding variables identified via a DAG constructed using a rigorous protocol. The adjusted effect estimates- the expected change in the PEG outcome for every standard deviation increase or decrease in the exposure (or category shift for categorical exposures) were the largest for sleep disturbance and obesity. Each SD increase in the PROMIS sleep disturbance T-score resulted in a mean 0.77 (95% CI: 0.66, 0.88) point increase in baseline PEG score. Compared to participants with normal BMI, adjusted mean PEG score was slightly higher by 0.37 points (95% CI: 0.09, 0.65) for overweight participants, about 0.8 to 0.9 points higher for those in obesity classes I and II, and 1.39 (95% CI: 0.98, 1.80) points higher for the most obese participants. Each SD increase in the PROMIS depression T-score was associated with a mean 0.28 (95% CI: 0.17, 0.40) point increase in baseline PEG score, while each SD decrease in number of alcoholic drinks per week resulted in a mean 0.12 (95% CI: 0.01, 0.23) increase in baseline PEG score in the adjusted model.

CONCLUSIONS

Several modifiable causal risk factors for cLBP - alcohol use, sleep disturbance, depression, and obesity- are associated with PEG, after adjusting for confounding variables identified via a DAG constructed using a rigorous protocol. Convergence of our findings for sleep disturbance, depression, and obesity with the results from MR studies, which have different designs and biases, strengthens the evidence for causal relationships between these risk factors and cLBP. The estimated effect of change in a risk factor on change in PEG were the largest for sleep disturbance and obesity. Future analyses will evaluate these relationships with longitudinal data.

Mental health during and after pregnancy in medically assisted reproduction: a danish cohort study

PURPOSE

Infertility is common and an increasing number of women go through medically assisted reproduction (fertility treatment) to achieve pregnancy. This may affect mental health. We examined if fertility treatment and the specific fertility treatment method used (in vivo or in vitro) were associated with impaired mental health during or after pregnancy.

METHODS

Using self-reported data from the Odense Child Cohort, we assessed prenatal stress by the 10-item Cohen Perceived Stress Scale (PSS-10) during pregnancy at median gestational week 27 and postnatal depressive symptoms by the Edinburgh Postnatal Depression Scale (EPDS) at median postpartum week 15. We compared fertility-treated women overall and by fertility treatment method to women who conceived spontaneously. We conducted linear regression analyses to evaluate the PSS-10 score dimensionally and logistic regression to evaluate EPDS scores above cut-off (≥ 11).

RESULTS

A total of 108 of 820 women (13%) gave birth after fertility treatment. Their prenatal mean stress (PSS-10) score was 11.38 compared to 11.78 for women who conceived spontaneously, leading to an adjusted mean difference of -0.09 points (95% confidence interval (CI): -1.88 to 1.69). In the fertility-treated group, 9.7% had EPDS scores ≥ 11 compared to 10.7% in the spontaneous conception group (adjusted odds ratio of 0.71 (95% CI: 0.26 to 1.91)). The MAR method (in vivo/vitro) did not influence these results.

CONCLUSION

Women who gave birth after fertility treatment did not report higher levels of prenatal stress or postpartum depressive symptoms than women who conceived spontaneously.

Management of acute myocardial infarction in chronic kidney disease in Germany: an observational study

BACKGROUND

Managing acute myocardial infarction (AMI) in patients with chronic kidney disease (CKD) or end-stage renal disease on dialysis (renal replacement therapy, RRT) presents challenges due to elevated complication risks. Concerns about contrast-related kidney damage may lead to the omission of guideline-directed therapies like percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) in this population.

METHODS

We analysed German-DRG data of 2016 provided by the German Federal Bureau of Statistics (DESTATIS). We included cases with a primary diagnosis of AMI (ST-Elevation Myocardial Infarction (STEMI) or Non-ST-Elevation Myocardial Infarction (NSTEMI) ICD-10: I21 or I22) with and without CKD or RRT. We calculated crude- and age-standardized hospitalization rates (ASR, per 100,000 person years). Furthermore, we calculated log-binominal regression models adjusting for sex, CKD, RRT, comorbidities, and place of residence to estimate adjusted relative-risks (aRR) for receiving treatments of interest in AMI, such as PCI or CABG.

RESULTS

We identified 217,514 AMI-cases (69,728 STEMI-cases and 147,786 NSTEMI-cases). AMI-cases without CKD had percutaneous coronary intervention (PCI) in 60.8%. In contrast, AMI-cases with CKD or RRT had PCI in 46.6% and 54.5%, respectively. The ASR for AMI-cases amounted to 184.7 (95%CI 183.5-185.8) per 100,000 person years. In regression analysis AMI-cases with CKD were less likely treated with PCI (aRR: 0.89 (95%CI 0.88-0.90)), compared to cases without CKD. AMI-Cases with RRT showed no difference in PCI rates (aRR: 1.0 (95%CI 0.97-1.03)) but were more frequently treated with CABG (aRR: 2.20 (95%CI 2.03-2.39)). Conversely, CKD was negatively associated with CABG (aRR: 0.71, 95%CI 0.67-0.75) when non-CKD cases were used as the reference group.

CONCLUSION

We show that AMI-cases with CKD underwent PCI less frequently, while RRT has no discernible impact on PCI utilization in AMI. Furthermore, AMI-cases with RRT exhibited a higher CABG rate.

Role of Advanced Glycation End Products in Mediating Glycated Haemoglobin and Pulse Wave Velocity in Healthy Adults

Background/Objectives: Poor metabolic control is associated with increased levels of advanced glycation end products (AGEs), which in turn may lead to increased arterial stiffness. The aim of this study was to estimate the association between glycated haemoglobin A1c (HbA1c) and aortic pulse wave velocity (a-PWV) in healthy subjects and to analyse the mediating effect of AGEs measured by skin autofluorescence (SAF) on this association. Methods: HbA1c, a-PWV and SAF were analysed in 390 healthy Spanish subjects from the EVasCu study (42.02 ± 13.14 years, 63.08% females). A directed acyclic graph (DAG) was generated to define the covariates to be included, and the model was confirmed via multiple linear regression analysis. Descriptive and exploratory analyses were performed to investigate the associations between variables. Finally, adjusted and unadjusted mediation analyses were performed to verify the influence of SAF on the main association between HbA1c and a-PWV. Results: Multiple linear regression analyses for a-PWV supported the validity of the structure in the DAG. Descriptive and exploratory analyses revealed that when the models were adjusted to include all covariates, the statistical significance of the main association disappeared. Mediation analysis revealed that SAF mediated 35.77% of the effect of HbA1c on a-PWV in the unadjusted model and 42.18% after adjusting for covariates. Conclusions: Our study suggests that increases in HbA1c levels are associated with increases in a-PWV and that this relationship is mediated by the SAF score in healthy adults.

Study protocol for a Prospective Observational study of Safety Threats and Adverse events in Trauma (PrO-STAT): a pilot study at a level-1 trauma centre in Canada

INTRODUCTION

Traumatic injuries are a significant public health concern globally, resulting in substantial mortality, hospitalisation and healthcare burden. Despite the establishment of specialised trauma centres, there remains considerable variability in trauma-care practices and outcomes, particularly in the initial phase of trauma resuscitation in the trauma bay. This stage is prone to preventable errors leading to adverse events (AEs) that can impact patient outcomes. Prior studies have identified common causes of these errors, including delayed diagnostics, disorganisation of staff, equipment issues and communication breakdowns, which collectively contribute to AEs. This study addresses gaps in understanding the root causes of these errors by evaluating the most frequent AEs in trauma care through real-time video reviews of resuscitations in the trauma bay. Insights from this evaluation will inform targeted interventions to improve procedural adherence, communication and overall team performance, ultimately reducing preventable errors and improving patient safety.

METHODS AND ANALYSIS

A prospective observational study will be conducted at St. Michael's Hospital, a level-1 trauma centre, to evaluate resuscitations in the trauma bay. All consecutive trauma team activations over 12 months will be included, with data collected using audio-visual recordings and physiological monitoring. A synchronised data capture and analysis platform will comprehensively assess AEs, errors and human and environmental factors during trauma resuscitations. The study aims to detect recurring error patterns, evaluate practice variations and correlate trauma team performance with in-hospital outcomes. Statistical analyses will include descriptive statistics, logistic regression models and multivariable analyses to identify associations and predictors of AEs and patient outcomes.

ETHICS AND DISSEMINATION

Institutional research ethics approval was obtained (SMH REB # 21-009). A modified consent model will be employed for participants. Staff, physicians and learners will be provided with information regarding the study and will have the option to opt-out or withdraw consent. Similarly, trauma patients and their next of kin will be informed about the study, with provisions for opting out or withdrawing consent within 48 hours of recording. Measures will be implemented to ensure data confidentiality, anonymity and respect for participants' autonomy and privacy. The study results will be shared through peer-reviewed journal publications and conference presentations, and key institutional stakeholders will be informed about developing strategies to improve patient safety in trauma care.

Physical activity and incident cardiovascular disease in breast cancer survivors: the Pathways Study

BACKGROUND

Breast cancer survivors experience higher rates of cardiovascular disease (CVD) than women without breast cancer, due in part to cardiotoxic cancer treatments and shared lifestyle risk factors. Physical activity is associated with lower mortality risk in breast cancer survivors, but associations with CVD have not been examined in detail.

METHODS

The Pathways Study is a prospective cohort study of 4504 women diagnosed with invasive breast cancer between 2005 and 2013. At enrollment, women self-reported their physical activities during the previous 6 months, which were dichotomized as meeting the Centers for Disease Control and Prevention's Physical Activity Guidelines for Americans (≥150 minutes of moderate-intensity or ≥75 minutes of vigorous-intensity activity per week) vs not. Incident CVD events (heart failure, cardiomyopathy, cardiac arrest, ischemic heart disease, stroke) occurring between enrollment and December 2021 were identified from electronic health records. Covariate-adjusted, competing-risks Cox regression models estimated associations between meeting physical activity guidelines and CVD risk.

RESULTS

Compared with women who did not meet physical activity guidelines at their diagnosis, those who did had a 25% lower risk of CVD (HR = 0.75, 95% CI = 0.60 to 0.94). Among the individual CVD outcomes, meeting physical activity guidelines was protective against incident cardiomyopathy (hazard ratio [HR] = 0.54, 95% CI = 0.31 to 0.95), heart failure (HR = 0.66, 95% CI = 0.50 to 0.87), and cardiac arrest (HR = 0.68, 95% CI = 0.49 to 0.99).

CONCLUSIONS

Meeting physical activity guidelines at breast cancer diagnosis was associated with lower risk of CVD after diagnosis. Studies investigating changes in physical activity after a breast cancer diagnosis and CVD risk are warranted.

Visceral adipose tissue mediates the relationship between left ventricular global longitudinal strain and insulin resistance among adults living with type 2 diabetes

BACKGROUND

Adipose tissue distribution plays a crucial role in the development of cardiovascular complications. In particular, visceral adipose tissue (VAT) has been linked to insulin resistance (IR) and cardiovascular disease (CVD). However, the relationship between VAT, cardiac dysfunction and the meditation capacity of VAT related to IR has not been fully characterized.

METHODS

This cross-sectional study included adults living with type 2 diabetes (T2D). VAT was measured using electrical bioimpedance and also estimated with the Metabolic Score for Visceral Fat (METS-VF). LV function was assessed using left ventricular global longitudinal strain (LV-GLS) by speckle tracking echocardiography analysis. Spearman correlation coefficients, adjusted linear regression models guided by direct acyclic diagrams and causal mediation analysis were performed.

RESULTS

Among 195 adults living with T2D (median age: 57, IQR: 49-64, women: 63%), VAT showed a positive association with LV-GLS (β = 0.482, 95% CI: 0.060-0.904, p = 0.039) after adjusting for relevant confounders. The effect was strongly replicated using METS-VF as a surrogate for VAT. The mediation analysis revealed that VAT accounted for 60.9% (95% CI: 15.82-171) of the total effect between IR and LV-GLS.

CONCLUSION

This study demonstrated a positive association between VAT and LV-GLS. This relationship was consistently observed using the clinical surrogate METS-VF. Visceral adiposity was identified as a strong mediator in the relationship between IR and LV-GLS, underscoring its role in the pathophysiology of cardiovascular disease in patients with T2D.

Real-world efficacy of transfusion with liberal or restrictive strategy in traumatic brain injury

OBJECTIVE

The short-term efficacy of red blood cell (RBC) transfusion among general traumatic brain injury (TBI) patients is unclear.

METHODS

We used the MIMIC database to compare the efficacy of liberal (10 g/dL) versus conservative (7 g/dL) transfusion strategy in TBI patients. The outcomes were neurological progression (decrease of Glasgow coma scale (GCS) of at least 2 points) and death within 28 days of ICU admission. Each eligible individual was cloned and assigned each of the replicates to one of the treatment arm. The imbalance induced by informative censoring was adjusted by inverse probability weighting. The standardized, weighted pooled logistic regression with 500 bootstrap resampling was used to estimate the cumulative risk difference and 95% confidence interval (CI).

RESULTS

Of the 1141 eligible individuals, 29.0% received RBC transfusion. Compared with the restrictive group, the liberal strategy reduced early death (3 days: 5%, 95% CI: 2%-7%; 7 days: 6%, 95% CI: 3%-11%); however, no significant difference of mortality risk at 28-day or neurological progression risk at any time points was observed. The risk of coagulopathy at 3 days was increased by 7% (95% CI: 1%-19%) in the liberal group. The subgroup analysis indicated a beneficial effect of liberal transfusion on mortality in hemodynamically unstable patients.

INTERPRETATION

Compared with the restrictive strategy, the liberal strategy does not improve the short-term neurological prognosis and death among patients with TBI in a real-world situation. The liberal strategy may be beneficial to survival at very early stage or in hemodynamically unstable subgroup.

Directed acyclic graph helps to understand the causality of malnutrition in under-5 children born small for gestational age

OBJECTIVES

Small-for-gestational age (SGA) is a causal factor for malnutrition (undernutrition). The available evidence on this causal relationship is based on observational studies and suffers from confounding and collider biases. This study aimed to construct a theoretical causal model to estimate the effect of SGA on malnutrition in children aged less than 5 years.

METHODS

For the causal model, we designated term-SGA status as the exposure variable and malnutrition at 6 months to 5 years of age (diagnosed by World Health Organization criteria) as the outcome variable. Causal estimands were formulated for three stakeholders. A "rapid narrative review" methodology was adopted for literature synthesis. Studies (observational and randomized) listing the causal factors of malnutrition in children aged less than 5 years from the Indian subcontinent were eligible. Four databases (PubMed, Scopus, Web of Science, and ProQuest) were searched and restricted to the last 10 years (search date: December 15, 2023). Information about the causal factors (covariates) of malnutrition and study characteristics was extracted from the article abstracts. Next, a causal model in the form of a directed acyclic graph (DAG) (DAGitty software) was constructed by connecting exposure, outcome, and covariate nodes using the sequential causal criteria of temporality, face validity, recourse to theory, and counterfactual thought experiments.

RESULTS

The search yielded 4818 records, of which 342 abstracts were included. Most of the studies were conducted in India (39%) and Bangladesh (27%). The literature synthesis identified 81 factors that were grouped into 17 nodes, referring to 5 domains: socioeconomic, parental, child-related, environmental, and political. The DAG identified 12 different minimal sufficient adjustment sets (conditioning sets for regression analysis) to estimate the total effect of SGA on malnutrition.

CONCLUSION

We offer an evidence-based causal diagram that will minimize bias due to improper selection of factors in studies focusing on malnutrition in term-SGA infants. The DAG and adjustment sets will facilitate the design and data analysis of future studies.

Is the relationship between chronic pain and mortality causal? A propensity score analysis

ABSTRACT

Chronic pain is a serious and prevalent condition that can affect many facets of life. However, uncertainty remains regarding the strength of the association between chronic pain and death and whether the association is causal. We investigate the pain-mortality relationship using data from 19,971 participants aged 51+ years in the 1998 wave of the U.S. Health and Retirement Study. Propensity score matching and inverse probability weighting are combined with Cox proportional hazards models to investigate whether exposure to chronic pain (moderate or severe) has a causal effect on mortality over a 20-year follow-up period. Hazard ratios (HRs) with 95% confidence intervals (CIs) are reported. Before adjusting for confounding, we find a strong association between chronic pain and mortality (HR: 1.32, 95% CI: 1.26-1.38). After adjusting for confounding by sociodemographic and health variables using a range of propensity score methods, the estimated increase in mortality hazard caused by pain is more modest (5%-9%) and the results are often also compatible with no causal effect (95% CIs for HRs narrowly contain 1.0). This attenuation highlights the role of confounders of the pain-mortality relationship as potentially modifiable upstream risk factors for mortality. Posing the depressive symptoms variable as a mediator rather than a confounder of the pain-mortality relationship resulted in stronger evidence of a modest causal effect of pain on mortality (eg, HR: 1.08, 95% CI: 1.01-1.15). Future work is required to model exposure-confounder feedback loops and investigate the potentially cumulative causal effect of chronic pain at multiple time points on mortality.