Causal mediation analysis in the context of clinical research

Medical Complexity Mediates Healthcare Resource Use in the Socially Vulnerable

GOAL

The objective of this retrospective, observational study was to assess the mediating effect of medical complexity on the relationship between social vulnerability and four acute care resource use outcomes-number of hospitalizations, emergency department (ED) visits, observation stays, and total visits. Such information may help healthcare managers better anticipate the effects of interventions targeted to the socially vulnerable in their patient population.

METHODS

Electronic health records of 147,496 adults served by 27 primary care practices in one large health system from 2015 to 2017 were used. Descriptive statistics were applied to characterize patients and the primary care practices included in the study. Causal mediation analyses using a modified Baron and Kenny approach were performed.

PRINCIPAL FINDINGS

Causal mediation analyses demonstrated that increased social vulnerability was associated with increased medical complexity (incidence rate ratio [IRR] = 1.57) and increased numbers of hospitalizations (IRR = 1.63), ED visits (IRR = 2.14), observation stays (IRR = 1.94), and total visits (IRR = 2.04). Effects remained significant, though attenuated, after adjusting for medical complexity (mediator), demographics, and medications (hospitalizations IRR = 1.44, ED visits IRR = 2.02, observation stays IRR = 1.74, total visits IRR = 1.86). Social vulnerability, given medical complexity, explained between 8% (ED visits) and 26% (hospitalizations) of the variation in outcomes.

PRACTICAL APPLICATIONS

These findings reinforce the need to modify interventions for medically complex adults to address their social needs and, consequently, reduce costly health services. Health systems seeking to reduce costly care can use these results to estimate savings in the treatment of patients with high social vulnerability-before they get chronic conditions and later as they seek care.

Aberrant Lumbopelvic Movements Predict Prospective Functional Decline in Older Adults with Chronic Low Back Pain

OBJECTIVE

To investigate if clinically observable aberrant lumbopelvic movements are associated with physical function at 12-month follow-up in older adults with chronic low back pain (CLBP), both directly and indirectly through baseline physical function.

DESIGN

Secondary analysis of a yearlong prospective cohort study.

SETTING

Clinical Research Laboratory.

PARTICIPANTS

Community-dwelling older adults with CLBP (N=250).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Data from 239 participants were analyzed. Participants were screened at baseline for aberrant lumbopelvic movements during active trunk flexion; total observable aberrant movements were recorded and summed (range 0-4). Latent constructs of physical function were developed from an array of perception-based and performance-based outcome measures at baseline and 12 months, respectively. Structural Equation Modeling was used to assess the direct effect of baseline aberrant movement score on the latent construct of 12-month physical function, and its indirect effect through baseline physical function.

RESULTS

Aberrant movements were present in most participants (64.7%) and had a significant negative total effect on 12-month physical function (γ= -0.278, P<.001). Aberrant movement score's direct effect and indirect effect, through baseline functioning, were significantly negatively associated with physical function at 12-months, after adjusting for covariates (γ=-0.068, P=.038; γ= -0.210, P<.001, respectively).

CONCLUSIONS

Aberrant lumbopelvic movements are associated with decreased physical function at 12-month follow-up in older adults with CLBP, independent of baseline physical function and covariates. Future studies should evaluate if screening for aberrant movements may inform prognostic and interventional efforts in this patient population.

Mediation effect of hypoxia in the relationship between obstructive sleep apnea and cardiovascular death risk

PURPOSE

This study aimed to explore the role of hypoxia in the relationship between obstructive sleep apnea (OSA) and cardiovascular disease (CVD) death risk based on data from the Sleep Heart Health Study (SHHS).

METHODS

Multivariate logistic regression analysis was used to analyze the association between OSA, hypoxia, and CVD death risk. Causal mediation analysis was performed to assess the role of hypoxia. The severity of OSA was evaluated by the apnea-hypopnea index (AHI), and the hypoxia was quantified by the percentage of sleep time with less than 90% oxygen saturation (PCTST90).

RESULTS

Of these 5,145 participants, 989 had no OSA, 2,110 had mild OSA, and 2,046 had moderate-to-severe OSA. After adjusting all confounders, mild OSA [odds ratio (OR): 1.800; 95% confidence interval (CI), 1.192-2.802], moderate-to-severe OSA (OR: 1.745; 95%CI, 1.148-2.758), 0 < PCTST90 < 1 (OR: 1.668; 95%CI, 1.184-2.385), and PCTST90 ≥ 1 (OR: 1.649; 95%CI, 1.148-2.400) were associated with an increased death risk of CVD. Furthermore, participants with mild OSA (OR: 3.742; 95%CI, 3.183-4.398) and moderate-to-severe OSA (OR: 19.671; 95%CI, 16.303-23.734) had a higher risk of hypoxia than those without OSA. Causal mediation analysis indicated that the average direct effect (ADM) of moderate-to-severe OSA and average causal mediation effect (ACME) of hypoxia on CVD death risk were 0.024 (95%CI, 0.004-0.040) and 0.013 (95%CI, 0.005-0.020), respectively, and the average mediating effect ratio was 33.94%.

CONCLUSION

Hypoxia played a mediating role in the increased death risk of CVD caused by OSA, and the mediating effect of hypoxia did not account for a large proportion.

Body mass index, blood glucose, and mortality in patients with ischemic stroke in the intensive care unit: A retrospective cohort study

BACKGROUND

Excessive BMI was associated with lower mortality after stroke. However, some believed that excessive BMI can lead to a poor prognosis because of some physiological mechanism, such as glucose metabolism disorder. Therefore, this study aims to discuss the association between mortality, BMI, and blood glucose.

MATERIALS AND METHODS

This was a retrospective observational study and all data were extracted from the Medical Information Mart for Intensive Care III database. The exposure was BMI classified into the normal weight group and the excessive weight group. The outcome concluded 30-day, 90-day, and 1-year mortality. The association between two groups and mortality was elucidated by Cox regression models, propensity score matching (PSM) and inverse probability of treatment weighting (IPTW). The underlying effect of blood glucose on the "obesity paradox" was analyzed by causal mediation analysis.

RESULTS

According to Cox regression models, a significant beneficial effect of excessive BMI in terms of mortality was observed: 30-day mortality (HR 0.57, 95% CI 0.35-0.90, P = 0.017), 90-day mortality (HR 0.53, 95% CI 0.36-0.78, P = 0.001), and 1-year mortality (HR 0.65, 95% CI 0.46-0.91, P = 0.013). After PSM and IPTW, we got a similar conclusion. The causal mediation analysis showed that the protective effect of excessive BMI on 30-day mortality reduced with the increase of blood glucose.

CONCLUSION

For ischemic stroke patients in the Intensive Care Unit, those with excessive BMI are associated with both lower short-term mortality and lower long-term mortality, while the protective effect on 30-day mortality weakened accompanied by the increase of blood glucose.

The Association of an Early Net Ultrafiltration Rate and 28-Day Mortality in Patients Receiving Continuous Kidney Replacement Therapy

Background: An early net ultrafiltration (NUF) rate may be associated with prognosis in patients receiving continuous kidney replacement therapy (CKRT). In this study, we tested whether high or low early NUF rates in patients treated with CKRT were associated with increased mortality. Methods: We conducted a retrospective, observational study among all patients in the Medical Information Mart for Intensive Care IV database who received CKRT for more than 24 h within 14 days after intensive care unit admission. We defined the early (initial 48 h) NUF rate as the amount of fluid removal per hour adjusted by the patients' weight and took it as a classified variable (low rate: <1.6, moderate rate: 1.6-3.1 and high rate: > 3.1 ml/kg/h). The association between 28-day mortality and the NUF rate was analyzed by logistic regression and mediation analyses. Results: A total of 911 patients were included in our study. The median NUF rate was 2.71 (interquartile range 1.90-3.86) ml/kg/h and the 28-day mortality was 40.1%. Compared with the moderate NUF rate, the low NUF rate (adjusted odds ratio 1.56, 95% CI 1.04-2.35, p = 0.032) and high NUF rate (adjusted odds ratio 1.43, 95% CI 1.02-2.01, p = 0.040) were associated with higher 28-day mortality. The putative effect of high or low NUF rates on 28 day mortality was not direct [adjusted average direct effects (ADE) for a low NUF rate = 0.92, p = 0.064; adjusted ADE for a high NUF rate = 1.03, p = 0.096], but mediated by effects of the NUF rate on fluid balance during the same period [adjusted average causal mediation effects (ACME) 0.96, p = 0.010 for a low NUF rate; adjusted ACME 0.99, p = 0.042 for a high NUF rate]. Moreover, we found an increase trend in the NUF rate corresponding to the lowest mortality when fluid input increased. Conclusion: Compared with NUF rates between 1.6-3.1 ml/kg/h in the first 48 h of CKRT, NUF rates > 3.1 and <1.6 ml/kg/h were associated with higher mortality.

Transgenerational health effects of in utero exposure to economic hardship: Evidence from preindustrial Southern Norway

We studied whether in utero exposure to economic hardship during a grandmother's pregnancy has a transgenerational effect on her grandchildren's health condition. We used an individual-level three-generation data set covering people born between 1734 and 1840 in the municipality of Rendalen in Norway. We found a culling effect in which grandchildren whose grandmothers gave birth in years of economic hardship lived approximately ten years longer than grandchildren whose mothers were born in years of economic well-being. This impact was only observed among the grandmothers who belong to the lowest social classes. Our results also showed that in higher social classes, economic hardship during a grandmother's pregnancy deteriorated her grandchildren's health by "scarring" the mother's health.

The role of body mass index in the association between dietary sodium intake and blood pressure: A mediation analysis with NHANES

BACKGROUND AND AIMS

Recent research demonstrated that obesity and high dietary sodium intake, the two established risk factors for hypertension, were associated with each other. The objective was to investigate the potential indirect effect of sodium intake on blood pressure via body mass index (BMI).

METHODS AND RESULTS

Using ten years data from US NHANES (2007-2016), the study included adult participants (>20 years old) who were not taking antihypertensive medications and without baseline diseases (n = 12,262). BMI was modelled as the mediator of sodium intake on systolic and diastolic blood pressure, adjusted for age, sex, socioeconomic status, smoking, drinking, physical activity, calorie intake, fluid intake and potassium intake. Mediation analysis was performed to evaluate total effect, direct effect and indirect effect via BMI. Subgroup analyses based on three age subgroups (20-40, 41-60 and ≥61 years old) were performed. The mean age was 39.29 (13.4) years and 53.1 (0.45) % were males. The mean BMI was 27.8 (6.20) kg/m². Overall, 1 g/d increase in sodium intake was associated with an increased systolic blood pressure by 0.36 (95% confidence interval 0.14 to 0.58) mmHg, with a direct effect (0.14 (0.09-0.19)) and an indirect effect via BMI (0.23 (0.02-0.44)). The indirect effect was mainly observed in participants ≤60 years old.

CONCLUSION

Sodium intake showed both direct effect and indirect effect (via BMI) on systolic blood pressure in US NHANES. The findings provide evidence for combining sodium restriction and weight reduction measures for prevention of hypertension. Cautions should be taken when generalizing the findings to other populations with lower average BMI.

Insights From the Ventricular Fibrillation Waveform Into the Mechanism of Survival Benefit From Bystander Cardiopulmonary Resuscitation

Background

The mechanism by which bystander cardiopulmonary resuscitation (CPR) improves survival following out‐of‐hospital cardiac arrest is unclear. We hypothesized that ventricular fibrillation (VF) waveform measures, as surrogates of myocardial physiology, mediate the relationship between bystander CPR and survival.

Methods and Results

We performed a retrospective cohort study of adult, bystander‐witnessed patients with out‐of‐hospital cardiac arrest with an initial rhythm of VF who were treated by a metropolitan emergency medical services system from 2005 to 2018. Patient, resuscitation, and outcome variables were extracted from emergency medical services and hospital records. A total of 3 VF waveform measures (amplitude spectrum area, peak frequency, and median peak amplitude) were computed from a 3‐second ECG segment before the initial shock. Multivariable logistic regression estimated the association between bystander CPR and survival to hospital discharge adjusted for Utstein elements. Causal mediation analysis quantified the proportion of survival benefit that was mediated by each VF waveform measure. Of 1069 patients, survival to hospital discharge was significantly higher among the 814 patients who received bystander CPR than those who did not (0.52 versus 0.43, respectively; P<0.01). The multivariable‐adjusted odds ratio for bystander CPR and survival was 1.6 (95% CI, 1.2, 2.1), and each VF waveform measure attenuated this association. Depending on the specific waveform measure, the proportion of mediation varied: 53% for amplitude spectrum area, 31% for peak frequency, and 29% for median peak amplitude.

Conclusions

Bystander CPR correlated with more robust initial VF waveform measures, which in turn mediated up to one‐half of the survival benefit associated with bystander CPR. These results provide insight into the biological mechanism of bystander CPR in VF out‐of‐hospital cardiac arrest.

Image-based assessment of sarcopenic obesity predicts mortality in major trauma

BACKGROUND

Patients with obesity are also at risk for sarcopenia, which is difficult to recognize in this population. Our study examines whether sarcopenic-obesity (SO) is independently associated with mortality in trauma.

METHODS

Using a retrospective database, we performed logistic regression analysis. . Admission CT scans were used to identify SO by calculating the visceral fat to skeletal muscle ratio >3.2.

RESULTS

Of 883 patients, the prevalence of SO was 38% (333). Patients with SO were more likely to be male (79% versus 43%, p < 0.001), older (mean 66.5 years versus 46.3 years, p < 0.001), and less likely to have an injury severity score (ISS) ≥ 24 (43% versus 55%, p = 0.0003). Using multivariable logistic regression analysis, SO was independently associated with mortality (OR 2.8; 95% CI 1.6-4.8, p < 0.001). Causal mediation analysis found admission hyperglycemia as a mediator for mortality.

CONCLUSIONS

Sarcopenic obesity is an independent predictor of mortality in major trauma.

Risk factors for adverse outcomes among 35 879 veterans with and without diabetes after diagnosis with COVID-19

INTRODUCTION

Risk factors and mediators of associations of diabetes with COVID-19 outcomes are unclear.

RESEARCH DESIGN AND METHODS

We identified all veterans receiving Department of Veterans Affairs healthcare with ≥1 positive nasal swab for SARS-CoV-2 (28 February-31 July 2020; n=35 879). We assessed associations of diabetes (with and without insulin use) with hospitalization, intensive care unit (ICU) admission, or death at 30 days, and with hazard of death until the censoring date. Among participants with diabetes (n=13 863), we examined associations of hemoglobin A1c and antihyperglycemic medication use with COVID-19 outcomes. We estimated mediation between diabetes and outcomes by comorbidities (cardiovascular disease, heart failure, and chronic kidney disease), statin or ACE inhibitor/angiotensin receptor blocker (ARB) use, and cardiac biomarkers (brain natriuretic peptide and troponin).

RESULTS

Diabetes with and without insulin use was associated with greater odds of hospitalization, ICU admission, and death at 30 days, and with greater hazard of death compared with no diabetes (OR 1.73, 1.76 and 1.63, and HR 1.61; and OR 1.39, 1.49 and 1.33, and HR 1.37, respectively, all p<0.0001). Prior sulfonylurea use was associated with greater odds of hospitalization and prior insulin use with hospitalization and death among patients with diabetes; among all participants, statin use was associated with lower mortality and ARB use with lower odds of hospitalization. Cardiovascular disease-related factors mediated <20% of associations between diabetes and outcomes.

CONCLUSIONS

Diabetes is independently associated with adverse outcomes from COVID-19. Associations are only partially mediated by common comorbidities.

Mediators of the Impact of Hourly Net Ultrafiltration Rate on Mortality in Critically Ill Patients Receiving Continuous Renal Replacement Therapy

OBJECTIVES

During continuous renal replacement therapy, a high net ultrafiltration rate has been associated with increased mortality. However, it is unknown what might mediate its putative effect on mortality. In this study, we investigated whether the relationship between early (first 48 hr) net ultrafiltration and mortality is mediated by fluid balance, hemodynamic instability, or low potassium or phosphate blood levels using mediation analysis and the primary outcome was hospital mortality.

DESIGN

Retrospective, observational study.

SETTING

Mixed medical and surgical ICUs at Austin hospital, Melbourne, Australia.

PATIENTS

Critically ill patients treated with continuous renal replacement therapy within 14 days of ICU admission who survived greater than 48 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We studied 347 patients (median [interquartile range] age: 64 yr [53-71 yr] and Acute Physiology and Chronic Health Evaluation III score: 73 (54-90)]. After adjustment for confounders, compared with a net ultrafiltration less than 1.01 mL/kg/hr, a net ultrafiltration rate greater than 1.75 mL/kg/hr was associated with significantly greater mortality (adjusted odds ratio, 1.15; 95% CI, 1.03-1.29; p = 0.011). Adjusted univariable mediation analysis found no suggestion of a causal mediation pathway for this effect by blood pressure, vasopressor therapy, or potassium levels, but identified a possible mediation effect for fluid balance (average causal mediation effect, 0.95; 95% CI, 0.89-1.00; p = 0.060) and percentage of phosphate measurements with hypophosphatemia (average causal mediation effect, 0.96; 95% CI, 0.92-1.00; p = 0.055). However, on multiple mediator analyses, these two variables showed no significant effect. In contrast, a high net ultrafiltration rate had an average direct effect of 1.24 (95% CI, 1.11-1.40; p < 0.001).

CONCLUSIONS

An early net ultrafiltration greater than 1.75 mL/kg/hr was independently associated with increased hospital mortality. Its putative effect on mortality was direct and not mediated by a causal pathway that included fluid balance, low blood pressure, vasopressor use, hypokalemia, or hypophosphatemia.

The impact of chest CT body composition parameters on clinical outcomes in COVID-19 patients

We assessed the impact of chest CT body composition parameters on outcomes and disease severity at hospital presentation of COVID-19 patients, focusing also on the possible mediation of body composition in the relationship between age and death in these patients. Chest CT scans performed at hospital presentation by consecutive COVID-19 patients (02/27/2020-03/13/2020) were retrospectively reviewed to obtain pectoralis muscle density and total, visceral, and intermuscular adipose tissue areas (TAT, VAT, IMAT) at the level of T7-T8 vertebrae. Primary outcomes were: hospitalization, mechanical ventilation (MV) and/or death, death alone. Secondary outcomes were: C-reactive protein (CRP), oxygen saturation (SO2), CT disease extension at hospital presentation. The mediation of body composition in the effect of age on death was explored. Of the 318 patients included in the study (median age 65.7 years, females 37.7%), 205 (64.5%) were hospitalized, 68 (21.4%) needed MV, and 58 (18.2%) died. Increased muscle density was a protective factor while increased TAT, VAT, and IMAT were risk factors for hospitalization and MV/death. All these parameters except TAT had borderline effects on death alone. All parameters were associated with SO2 and extension of lung parenchymal involvement at CT; VAT was associated with CRP. Approximately 3% of the effect of age on death was mediated by decreased muscle density. In conclusion, low muscle quality and ectopic fat accumulation were associated with COVID-19 outcomes, VAT was associated with baseline inflammation. Low muscle quality partly mediated the effect of age on mortality.

The Interplay Between Postsynaptic Striatal D2/3 Receptor Availability, Adversity Exposure and Odd Beliefs: A [11C]-Raclopride PET Study

BACKGROUND

Between unaffected mental health and diagnosable psychiatric disorders, there is a vast continuum of functioning. The hypothesized link between striatal dopamine signaling and psychosis has guided a prolific body of research. However, it has been understudied in the context of multiple interacting factors, subclinical phenotypes, and pre-postsynaptic dynamics.

METHOD

This work investigated psychotic-like experiences and D2/3 dopamine postsynaptic receptor availability in the dorsal striatum, quantified by in vivo [11C]-raclopride positron emission tomography, in a sample of 24 healthy male individuals. Additional mediation and moderation effects with childhood trauma and key dopamine-regulating genes were examined.

RESULTS

An inverse relationship between nondisplaceable binding potential and subclinical symptoms was identified. D2/3 receptor availability in the left putamen fully mediated the association between traumatic childhood experiences and odd beliefs, that is, inclinations to see meaning in randomness and unfounded interpretations. Moreover, the effect of early adversity was moderated by a DRD2 functional variant (rs1076560). The results link environmental and neurobiological influences in the striatum to the origination of psychosis spectrum symptomology, consistent with the social defeat and diathesis-stress models.

CONCLUSIONS

Adversity exposure may affect the dopamine system as in association with biases in probabilistic reasoning, attributional style, and salience processing. The inverse relationship between D2/3 availability and symptomology may be explained by endogenous dopamine occupying the receptor, postsynaptic compensatory mechanisms, and/or altered receptor sensitivity. This may also reflect a cognitively stabilizing mechanism in non-help-seeking individuals. Future research should comprehensively characterize molecular parameters of dopamine neurotransmission along the psychosis spectrum and according to subtype profiling.

Individualized brain development and cognitive outcome in infants with congenital heart disease

Infants with congenital heart disease are at risk of neurodevelopmental impairments, the origins of which are currently unclear. This study aimed to characterize the relationship between neonatal brain development, cerebral oxygen delivery and neurodevelopmental outcome in infants with congenital heart disease. A cohort of infants with serious or critical congenital heart disease (N = 66; N = 62 born ≥37 weeks) underwent brain MRI before surgery on a 3T scanner situated on the neonatal unit. T2-weighted images were segmented into brain regions using a neonatal-specific algorithm. We generated normative curves of typical volumetric brain development using a data-driven technique applied to 219 healthy infants from the Developing Human Connectome Project (dHCP). Atypicality indices, representing the degree of positive or negative deviation of a regional volume from the normative mean for a given gestational age, sex and postnatal age, were calculated for each infant with congenital heart disease. Phase contrast angiography was acquired in 53 infants with congenital heart disease and cerebral oxygen delivery was calculated. Cognitive and motor abilities were assessed at 22 months (N = 46) using the Bayley scales of Infant and Toddler Development-Third Edition. We assessed the relationship between atypicality indices, cerebral oxygen delivery and cognitive and motor outcome. Additionally, we examined whether cerebral oxygen delivery was associated with neurodevelopmental outcome through the mediating effect of brain volume. Negative atypicality indices in deep grey matter were associated with both reduced neonatal cerebral oxygen delivery and poorer cognitive abilities at 22 months across the whole sample. In infants with congenital heart disease born ≥37 weeks, negative cortical grey matter and total tissue volume atypicality indices, in addition to deep grey matter structures, were associated with poorer cognition. There was a significant indirect relationship between cerebral oxygen delivery and cognition through the mediating effect of negative deep grey matter atypicality indices across the whole sample. In infants born ≥37 weeks, cortical grey matter and total tissue volume atypicality indices were also mediators of this relationship. In summary, lower cognitive abilities in toddlers with congenital heart disease were associated with smaller grey matter volumes before cardiac surgery. The aetiology of poor cognition may encompass poor cerebral oxygen delivery leading to impaired grey matter growth. Interventions to improve cerebral oxygen delivery may promote early brain growth and improve cognitive outcomes in infants with congenital heart disease.

Psychosocial Moderators and Mediators of Sensorimotor Exercise in Low Back Pain: A Randomized Multicenter Controlled Trial

The effects of exercise interventions on unspecific chronic low back pain (CLBP) have been investigated in many studies, but the results are inconclusive regarding exercise types, efficiency, and sustainability. This may be because the influence of psychosocial factors on exercise induced adaptation regarding CLBP is neglected. Therefore, this study assessed psychosocial characteristics, which moderate and mediate the effects of sensorimotor exercise on LBP. A single-blind 3-arm multicenter randomized controlled trial was conducted for 12-weeks. Three exercise groups, sensorimotor exercise (SMT), sensorimotor and behavioral training (SMT-BT), and regular routines (CG) were randomly assigned to 662 volunteers. Primary outcomes (pain intensity and disability) and psychosocial characteristics were assessed at baseline (M1) and follow-up (3/6/12/24 weeks, M2-M5). Multiple regression models were used to analyze whether psychosocial characteristics are moderators of the relationship between exercise and pain, meaning that psychosocial factors and exercise interact. Causal mediation analysis were conducted to analyze, whether psychosocial characteristics mediate the exercise effect on pain. A total of 453 participants with intermittent pain (mean age = 39.5 ± 12.2 years, f = 62%) completed the training. It was shown, that depressive symptomatology (at M4, M5), vital exhaustion (at M4), and perceived social support (at M5) are significant moderators of the relationship between exercise and the reduction of pain intensity. Further depressive mood (at M4), social-satisfaction (at M4), and anxiety (at M5 SMT) significantly moderate the exercise effect on pain disability. The amount of moderation was of clinical relevance. In contrast, there were no psychosocial variables which mediated exercise effects on pain. In conclusion it was shown, that psychosocial variables can be moderators in the relationship between sensorimotor exercise induced adaptation on CLBP which may explain conflicting results in the past regarding the merit of exercise interventions in CLBP. Results suggest further an early identification of psychosocial risk factors by diagnostic tools, which may essential support the planning of personalized exercise therapy. Level of Evidence: Level I. Clinical Trial Registration: DRKS00004977, LOE: I, MiSpEx: grant-number: 080102A/11-14. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00004977.

Functional relevance of resistance training-induced neuroplasticity in health and disease

Repetitive, monotonic, and effortful voluntary muscle contractions performed for just a few weeks, i.e., resistance training, can substantially increase maximal voluntary force in the practiced task and can also increase gross motor performance. The increase in motor performance is often accompanied by neuroplastic adaptations in the central nervous system. While historical data assigned functional relevance to such adaptations induced by resistance training, this claim has not yet been systematically and critically examined in the context of motor performance across the lifespan in health and disease. A review of muscle activation, brain and peripheral nerve stimulation, and imaging data revealed that increases in motor performance and neuroplasticity tend to be uncoupled, making a mechanistic link between neuroplasticity and motor performance inconclusive. We recommend new approaches, including causal mediation analytical and hypothesis-driven models to substantiate the functional relevance of resistance training-induced neuroplasticity in the improvements of gross motor function across the lifespan in health and disease.

Systemic evaluation of the relationship between psoriasis, psoriatic arthritis and osteoporosis: observational and Mendelian randomisation study

OBJECTIVES AND METHODS

With 432 513 samples from UK Biobank dataset, multivariable linear/logistic regression were used to estimate the relationship between psoriasis/psoriatic arthritis (PsA) and estimated bone mineral density (eBMD)/osteoporosis, controlling for potential confounders. Here, confounders were set in three ways: model0 (including age, height, weight, smoking and drinking), model1 (model0 +regular physical activity) and model2 (model1 +medication treatments). The eBMD was derived from heel ultrasound measurement. And 4904 patients with psoriasis and 847 patients with PsA were included in final analysis. Mendelian randomisation (MR) approach was used to evaluate the causal effect between them.

RESULTS

Lower eBMD were observed in patients with PsA than in controls in both model0 (β-coefficient=-0.014, p=0.0006) and model1 (β-coefficient=-0.013, p=0.002); however, the association disappeared when conditioning on treatment with methotrexate or ciclosporin (model2) (β-coefficient=-0.005, p=0.28), mediation analysis showed that 63% of the intermediary effect on eBMD was mediated by medication treatment (p<2E-16). Patients with psoriasis without arthritis showed no difference of eBMD compared with controls. Similarly, the significance of higher risk of osteopenia in patients with PsA (OR=1.27, p=0.002 in model0) could be eliminated by conditioning on medication treatment (p=0.244 in model2). Psoriasis without arthritis was not related to osteopenia and osteoporosis. The weighted Genetic Risk Score analysis found that genetically determined psoriasis/PsA were not associated with eBMD (p=0.24 and p=0.88). Finally, MR analysis showed that psoriasis/PsA had no causal effect on eBMD, osteoporosis and fracture.

CONCLUSIONS

The effect of PsA on osteoporosis was secondary (eg, medication) but not causal. Under this hypothesis, psoriasis without arthritis was not a risk factor for osteoporosis.

Early Parenting Intervention Effects on Brain Responses to Maternal Cues Among High-Risk Children

OBJECTIVE

Early adversity is correlated with increased risk for negative outcomes, including psychopathology and atypical neurodevelopment. The authors aimed to test the causal impact of an early parenting intervention (Attachment and Biobehavioral Catch-Up; ABC) on children's neural processing of parent cues and on psychosocial functioning in a longitudinal randomized clinical trial.

METHODS

Participants (N=68, mean age, 10.0 years [SD=0.8 years]) were 46 high-risk children whose parents were randomly assigned to receive either the ABC intervention (N=22) or a control intervention (N=24) while the children were infants, in addition to a comparison sample of low-risk children (N=22). During functional MRI scanning, children viewed pictures of their own mothers and of a stranger.

RESULTS

Children in the ABC condition showed greater maternal cue-related activation than children in the control condition in clusters of brain regions, including the precuneus, the cingulate gyrus, and the hippocampus, regions commonly associated with social cognition. Additionally, greater activity in these regions was associated with fewer total behavior problems. There was an indirect effect of early intervention on middle childhood psychosocial functioning mediated through increased activity in brain regions in response to maternal cues.

CONCLUSIONS

These results suggest that early parenting intervention (in this case the ABC intervention) can enhance brain regions supporting children's social cognitive development. In addition, the findings highlight these brain effects as a possible neural pathway through which ABC may prevent future behavior problems among high-risk children, yielding psychosocial benefits that endure through at least middle childhood without the need to intervene with the child directly.

Central venous pressure measurement is associated with improved outcomes in septic patients: an analysis of the MIMIC-III database

Purpose

Measurement of central venous pressure (CVP) can be a useful clinical tool. However, the formal utility of CVP measurement in preventing mortality in septic patients has never been proven.

Methods

The Medical Information Mart for Intensive Care III (MIMIC-III) database was searched to identify septic patients with and without CVP measurements. The primary outcome was 28-day mortality. Multivariate regression was used to elucidate the relationship between CVP measurement and 28-day mortality, and propensity score matching (PSM) and an inverse probability of treatment weighing (IPTW) were employed to validate our findings.

Results

A total of 10,275 patients were included in our study, of which 4516 patients (44%) underwent CVP measurement within 24 h of intensive care unit (ICU) admission. The risk of 28-day mortality was reduced in the CVP group (OR 0.60 (95% CI 0.51–0.70; p < 0.001)). Patients in the CVP group received more fluid on day 1 and had a shorter duration of mechanical ventilation and vasopressor use, and the reduction in serum lactate was greater than that in the no CVP group. The mediating effect of serum lactate reduction was significant for the whole cohort (p = 0.04 for the average causal mediation effect (ACME)) and patients in the CVP group with an initial CVP level below 8 mmHg (p = 0.04 for the ACME).

Conclusion

CVP measurement was associated with decreased risk-adjusted 28-day mortality among patients with sepsis and was proportionally mediated through serum lactate reduction.

The association between cystatin C and COPD: a meta-analysis and systematic review

BACKGROUND

In recent years, many studies have discovered that cystatin C (Cys C) may play an important role in respiratory diseases, especially in chronic obstructive pulmonary disease (COPD). However, the findings of these studies were inconsistent. This systematic review and meta-analysis aimed to assess the relationship between serum Cys C and COPD.

METHODS

We conducted a systematic literature search in PubMed, Embase, Web of Science, Wanfang databases, and the China National Knowledge Infrastructure. The standardized mean difference (SMD), Fisher's Z-value and 95% confidence interval (CI) were calculated to investigate the effect sizes. Subgroup analyses were performed on disease status, ethnicity, assay method, and study design. Sensitivity was performed, and publication bias was assessed.

RESULTS

A total of 15 studies, including 4079 COPD patients and 5949 controls, were included in this meta-analysis. The results showed that serum Cys C levels in patients with COPD were significantly higher than those in controls (SMD = 0.99, 95% CI =0.62-1.37, P < 0.001), especially in AECOPD (SMD = 1.59, 95% CI =1.05-2.13, P < 0.001), and there were statistically different among AECOPD and SCOPD (SMD = 0.35, 95% CI =0.10-0.59, P = 0.005). The serum Cys C levels were negatively correlated with FEV1%pre (Z = - 0.45, 95%CI = -0.58--0.32, P = 0.011) and FEV1/FVC (Z = - 0.32, 95%CI = -0.50--0.14, P = 0.006). The serum Cys C levels were independent of ethnicity, assay method, and study design.

CONCLUSION

Serum Cys C levels were associated with COPD and COPD exacerbation, and they were inversely correlated with FEV1%pre and FEV1/FVC.

Effects of the Incidence Density of Fever (IDF) on Patients Resuscitated From In-Hospital Cardiac Arrest: A Mediation Analysis

Objective: The aim of this research was to study the factors contributing to the survival rate of in-hospital cardiac arrest (IHCA) and to determine whether the incidence density of fever (IDF) acts as a mediator.

Methods: Data from patients with IHCA who survived more than 48 h were collected from 2011 to 2017. IDF was defined as the fever duration divided by the hospitalization duration, prolonged fever was defined as fever lasting for more than 5 days, and early fever was defined as an initial onset within the first 2 days of IHCA. Possible clinical variables associated with IDF were examined by linear regression, and possible clinical variables associated with survival rate were examined by univariate and multivariate analyses. IDF was investigated as a mediator of the indirect effects of the risk factors on survival.

Results: In our retrospective study, the median IDF was 0, with an interquartile range from 0 to 0.42. Prolonged fever was noted in 16% (97/605) of the total, and early fever was noted in 17.2% (104/605) of the total. Linear regression results showed that positive chest X-ray, central venous catheter and Glasgow Coma Score (GCS) ≤ 8 were related to IDF. The IDF (OR: 0.36, 95% CI, 0.13–0.97, P = 0.04), prolonged fever (adjusted OR = 0.13, 95% CI, 0.06–0.29, P < 0.001), positive chest X-ray (OR: 0.67, 95% CI, 0.46–0.98, P = 0.04), central venous catheter placement (OR: 0.54, 95% CI, 0.34–0.89, P = 0.01), and endotracheal intubation (OR: 0.47, 95% CI, 0.33–0.69, P < 0.001) were also related to the negative outcome of hospital discharge after adjustment. Additionally, positive chest X-ray had a 19% effect on survival outcome through IDF as a mediator, and the indirect effect of central venous catheter mediated by IDF accounted for 10% of the total.

Conclusions: A higher IDF, prolonged fever, a positive chest X-ray, the use of a central venous catheter and endotracheal intubation reduced the survival rate of these patients, and the detrimental impacts of a positive chest X-ray and the use of a central venous catheter on survival outcomes were partially mediated by IDF.

Early lactate measurement is associated with better outcomes in septic patients with an elevated serum lactate level

Background

The optimal timing of lactate measurement for septic patients in the intensive care unit (ICU) remains controversial, and whether initiating and repeating the lactate measurement earlier could make a difference for septic patients with an elevated lactate level remains unexplored.

Methods

This was a retrospective observational study that included septic patients with an initial lactate level > 2.0 mmol/L after ICU admission, and all data were extracted from the Medical Information Mart for Intensive Care III (MIMIC-III) database. The main exposure of interest was the early lactate measurement, which was defined as an initial lactate level measurement within 1 h after ICU admission. The primary outcome was 28-day mortality.

Results

A total of 2642 eligible subjects were enrolled, including 738 patients who had initial lactate measurements completed within 1 h (EL group) and 1904 patients who had initial lactate measurements completed more than 1 h after ICU admission (LL group). A significant beneficial effect of early lactate measurement in terms of 28-day mortality was observed: the adjusted odds ratio (OR) was 0.69 (95% CI 0.55–0.87; p = 0.001), and the mediation effect of the time to initial vasopressor administration was significant (average causal mediation effect (ACME) − 0.018; 95% CI − 0.005 approximately to − 0.036; p < 0.001). A strong relationship between delayed initial lactate measurement and risk-adjusted 28-day mortality was noted (OR 1.04; 95% CI 1.02–1.05; p < 0.001). Each hour of delay in remeasuring the lactate level was associated with an increase in 28-day mortality in the EL group (OR 1.09; 95% CI 1.04–1.15; p < 0.001). Further analysis demonstrated that repeating the measurement 3 h after the initial lactate measurement led to a significant difference.

Conclusions

Early lactate measurement is associated with a lower risk-adjusted 28-day mortality rate in septic patients with lactate levels > 2.0 mmol/L. A shorter time to the initial vasopressor administration may contribute to this relationship. Repeating the lactate measurement within 3 h after the initial measurement is appropriate for patients whose lactate levels were measured within 1 h of admission.

Graphic health warning posters increase some adolescents' future cigarette use susceptibility by changing normative perceptions of smoking: A case of mediated moderation

Prior work suggests that exposure to graphic health warning posters (GWPs) at retail point-of-sale may increase future cigarette smoking susceptibility in adolescents who are already at risk for future smoking, but not among committed never-smokers. However, little is known about what psychological mechanisms may account for this effect of GWPs on at-risk youths. Participants (N = 441) aged 11-17 years were randomized to experimental shopping conditions in a life-sized model convenience store, in which GWPs were absent ("status quo"; n = 107) or visibly displayed near the check-out area (n = 334). Participants completed pre- and post- "shopping" measures of future smoking susceptibility, descriptive and injunctive smoking norms, and perceived harms of smoking. A series of linear regression analyses assessed whether norms and harms differentially mediated the effect of experimental condition on future smoking susceptibility in committed never smokers compared with at-risk youths. Tests showed evidence for mediated moderation of the effect of GWP exposure on future smoking susceptibility, such that changes in injunctive norms (i.e., greater perceived social disapproval)-but not descriptive norms or perceived smoking harms-partially accounted for the effect of GWPs on smoking susceptibility in at-risk youths (average causal mediation effect: B = 0.51 [0.14-1.22], p = .02), but not among committed never smokers. For adolescents already at risk of future smoking, GWPs increase perceptions of cigarettes as less socially acceptable, which may increase susceptibility to future smoking in this group. Future work should examine reactance to antismoking messaging among youth at risk for future smoking. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Associations between prenatal exposure to bisphenol a and neonatal outcomes in a Taiwanese cohort study: Mediated through oxidative stress?

This study determined whether maternal bisphenol A (BPA) exposure influences birth outcomes through oxidative stress and estimated the daily intake of BPA through breast milk for infants. One hundred and eighty-six pregnant women without pregnancy complications were enrolled and maternal urine was collected in the third trimester. Postnatal breast milk was collected in the first and third months after delivery. Concentrations of BPA were determined through ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Generalized additive model-penalized regression splines and a multivariable regression model were employed to determine the effects of BPA exposure and oxidative stress levels on birth outcomes. A causal mediation analysis was conducted to clarify the mediation effects of oxidative stress due to maternal BPA exposure on birth outcomes. The daily intake of BPA in breast milk was calculated using probabilistic risk assessment methods. The geometric means (geometric standard deviation) of BPA levels for maternal urine and first- and third-month breast milk were 2.19 (2.88) μg/g creatinine., 1.35 (3.53) ng/g, and 3.17 (2.97) ng/g, respectively. No significant mediation existed among maternal BPA exposure, oxidative stress level, and neonatal head circumference. Three percent of 1-monthold babies and 1% of 3-month-old babies exceeded the BPA tolerable daily intake of 4 μg/kg-bw/day proposed by the European Food Safety Authority. This study revealed the BPA exposure profile for pregnant women and infants in northern Taiwan. The marginally significant correlation between maternal BPA exposure and neonatal head circumference should be considered.

Exploring genetic counselors' perceptions of usefulness and intentions to use refined risk models in clinical care based on the Technology Acceptance Model (TAM)

Pathogenic germline mutations in the BRCA1 or BRCA2 genes are associated with an elevated lifetime risk for breast (50%-85% risk) and ovarian cancer (20%-40% risk). Genome-wide association studies have identified over 100 genetic variants associated with modified breast and/or ovarian cancer risk in BRCA1 and BRCA2 carriers. Risk models generated based on these variants have shown that these genetic modifiers strongly influence absolute risk of developing breast or ovarian cancer in BRCA mutation carriers. There is a lack of understanding, however, about the clinical applicability and utility of these risk models. To investigate this gap, we collected survey data from 274 cancer genetic counselors (GCs) through the National Society of Genetic Counselors Cancer Special Interest Group. Questions assessed perceptions of usefulness and intentions of genetic counselors to use these refined risk models in clinical care based on the Technology Acceptance Model (TAM). We found that GCs' reactions to the estimates were largely positive, though they thought the possibility of changing management based on results was unlikely. Additionally, we found that more experienced GCs were more likely to consider refined risk estimates in clinic. Support also was provided for core predictions within the TAM, whereby the perceived usefulness (indirect effect est. = 0.08, 95% CI: [0.04, 0.13]) and perceived ease of use (indirect effect est. = 0.078, 95% CI: [0.04, 0.13]) of refined risk estimates were indirectly associated with intentions to use via attitudes.

Association between ambient air pollution and pregnancy rate in women who underwent IVF

STUDY QUESTION

Are the concentrations of five criteria air pollutants associated with probabilities of biochemical pregnancy loss and intrauterine pregnancy in women?

SUMMARY ANSWER

Increased concentrations of ambient particulate matter (PM10), nitrogen dioxide (NO2), carbon monoxide (CO) during controlled ovarian stimulation (COS) and after embryo transfer were associated with a decreased probability of intrauterine pregnancy.

WHAT IS KNOWN ALREADY

Exposure to high ambient air pollution was suggested to be associated with low fertility and high early pregnancy loss in women.

STUDY DESIGN, SIZE, DURATION

Using a retrospective cohort study design, we analysed 6621 cycles of 4581 patients who underwent one or more fresh IVF cycles at a fertility centre from January 2006 to December 2014, and lived in Seoul at the time of IVF treatment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

To estimate patients' individual exposure to air pollution, we computed averages of hourly concentrations of five air pollutants including PM10, NO2, CO, sulphur dioxide (SO2) and ozone (O3) measured at 40 regulatory monitoring sites in Seoul for each of the four exposure periods: period 1 (start of COS to oocyte retrieval), period 2 (oocyte retrieval to embryo transfer), period 3 (embryo transfer to hCG test), and period 4 (start of COS to hCG test). Hazard ratios (HRs) from the time-varying Cox-proportional hazards model were used to estimate probabilities of biochemical pregnancy loss and intrauterine pregnancy for an interquartile range (IQR) increase in each air pollutant concentration during each period, after adjusting for individual characteristics. We tested the robustness of the result using generalised linear mixed model, accounting for within-woman correlation.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean age of the women was 35 years. Average BMI was 20.9 kg/m2 and the study population underwent 1.4 IVF cycles on average. Cumulative pregnancy rate in multiple IVF cycles was 51.3% per person. Survival analysis showed that air pollution during periods 1 and 3 was generally associated with IVF outcomes. Increased NO2 (adjusted HR = 0.93, 95% CI: 0.87, 0.99) and CO (0.94, 95% CI: 0.89, 1.00) during period 1 were associated with decreased probability of intrauterine pregnancy. PM10 (0.92, 95% CI: 0.85, 0.99), NO2 (0.93, 95% CI = 0.86, 1.00) and CO (0.93, 95% CI: 0.87, 1.00) levels during period 3 were also inversely associated with intrauterine pregnancy. Both PM10 (1.17, 95% CI: 1.04 1.33) and NO2 (1.18, 95% CI: 1.03, 1.34) during period 3 showed positive associations with biochemical pregnancy loss.

LIMITATIONS, REASONS FOR CAUTION

The district-specific ambient air pollution treated as an individual exposure may not represent the actual level of each woman's exposure to air pollution. Smoking, working status, parity or gravidity of women, and semen analysis data were not included in the analysis.

WIDER IMPLICATIONS OF THE FINDINGS

This study provided evidence of an association between increased ambient concentrations of PM10, NO2 and CO and reduced probabilities for achieving intrauterine pregnancy using multiple IVF cycle data. Specifically, our results indicated that lower intrauterine pregnancy rates in IVF cycles may be linked to ambient air pollution during COS and the post-transfer period.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013 R1A6A3A04059017, 2016 R1D1A1B03933410 and 2018 R1A2B6004608) and the National Cancer Center of Korea (NCC-1810220-01). The authors report no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Low back pain

Low back pain affects individuals of all ages and is a leading contributor to disease burden worldwide. Despite advancements in assessment and treatment methods, the management of low back pain remains a challenge for researchers and clinicians alike. One reason for the limited success in identifying effective treatments is the large variation in the manifestations, possible causes, precipitating and maintaining factors, course, prognosis and consequences in terms of activity interference and quality of life. However, despite these challenges, steady progress has been achieved in the understanding of back pain, and important steps in the understanding of the psychological and social risk factors, genetics and brain mechanisms of low back pain have been made. These new findings have given impetus to the development of new diagnostic procedures, evidence-based screening methods and more targeted interventions, which underscore the need for a multidisciplinary approach to the management of low back pain that integrates biological, psychological and social aspects.

Temporal Trends in the Use of Therapeutic Hypothermia for Out-of-Hospital Cardiac Arrest

IMPORTANCE

Despite evidence that therapeutic hypothermia improves patient outcomes for out-of-hospital cardiac arrest, use of this therapy remains low.

OBJECTIVE

To determine whether the use of therapeutic hypothermia and patient outcomes have changed after publication of the Targeted Temperature Management trial on December 5, 2013, which supported more lenient temperature management for out-of-hospital cardiac arrest.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort was conducted between January 1, 2013, and December 31, 2016, of 45 935 US patients in the Cardiac Arrest Registry to Enhance Survival who experienced out-of-hospital cardiac arrest and survived to hospital admission.

EXPOSURES

Calendar time by quarter year.

MAIN OUTCOMES AND MEASURES

Use of therapeutic hypothermia and patient survival to hospital discharge.

RESULTS

Among 45 935 patients (17 515 women and 28 420 men; mean [SD] age, 59.3 [18.3] years) who experienced out-of-hospital cardiac arrest and survived to admission at 649 US hospitals, overall use of therapeutic hypothermia during the study period was 46.4%. In unadjusted analyses, the use of therapeutic hypothermia dropped from 52.5% in the last quarter of 2013 to 46.0% in the first quarter of 2014 after the December 2013 publication of the Targeted Temperature Management trial. Use of therapeutic hypothermia remained at or below 46.5% through 2016. In segmented hierarchical logistic regression analysis, the risk-adjusted odds of use of therapeutic hypothermia was 18% lower in the first quarter of 2014 compared with the last quarter of 2013 (odds ratio, 0.82; 95% CI, 0.71-0.94; P = .006). Similar point-estimate changes over time were observed in analyses stratified by presenting rhythm of ventricular tachycardia or ventricular fibrillation (odds ratio, 0.89; 95% CI, 0.71-1.13, P = .35) and pulseless electrical activity or asystole (odds ratio, 0.75; 95% CI, 0.63-0.89; P = .001). Overall risk-adjusted patient survival was 36.9% in 2013, 37.5% in 2014, 34.8% in 2015, and 34.3% in 2016 (P < .001 for trend). In mediation analysis, temporal trends in use of hypothermia did not consistently explain trends in patient survival.

CONCLUSIONS AND RELEVANCE

In a US registry of patients who experienced out-of-hospital cardiac arrest, the use of guideline-recommended therapeutic hypothermia decreased after publication of the Targeted Temperature Management trial, which supported more lenient temperature thresholds. Concurrent with this change, survival among patients admitted to the hospital decreased, but was not mediated by use of hypothermia.

Ulinastatin is effective in reducing mortality for critically ill patients with sepsis: a causal mediation analysis

Ulinastatin has been found to have anti-inflammatory effect for patients with sepsis. However, its clinical effects were conflicting. The study aimed to investigate the cost-effectiveness of ulinastatin and to perform mediation analysis to explore the proportion of the total effects that can be explained by inflammatory responses. This is a retrospective study involving critically ill patients with sepsis from January 2014 to July 2017. A total of 263 patients were included in the study, involving 179 patients in the ulinastatin group and 84 in the control group. Ulinastatin group showed significantly lower 28-day mortality rate than that in the control group (31% vs. 55%; p < 0.001). Both total (46330 [26000,83500] vs. 19870 [8747,41140] RMB; p < 0.01) and drug cost (18210 [9492,31920] vs. 7230 [2675,19270] RMB; p < 0.01) were significantly higher in the ulinastatin group than the control group. In multivariable model, the adjusted odds ratio for ulinastatin was 0.304 (95% CI: 0.152 to 0.592; p = 0.001). The mediation analysis showed that the use of ulinastatin was able to reduce the probability of death by 23.5%. The average causal mediation effect of delta C-reactive protein (CRP) was 8%, accounting for 35% of the total effect.

Investigating potential mediator between statin and coronary artery calcification

Statins are mainstay anti-lipidaemic treatments for preventing cardiovascular diseases but also known to increase coronary artery calcification (CAC). However, underlying relationship between statin and CAC is still unclear. This study explored the mediating role of five statin-related biochemical factors [i.e., low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglyceride, glucose, and high sensitivity C-reactive protein levels]. Seoul Metabolic Syndrome cohort study includes 1370 participants suspected of metabolic syndrome. For causal mediation analysis, the dataset for 2016 including 847 participants with coronary computed tomography without any missing value were analysed using the Mediation package in R software. This study identified a causal mediation mechanism of HDL-cholesterol among the five biochemical factors. It implied that statin treatment increases the HDL-cholesterol level, leading to decreasing the probability of CAC score > 0. Estimated values of interest in HDL-cholesterol mediation were (1) average causal mediation effect, -0.011 with 95% CI [-0.025, -0.003], (2) average direct effect, 0.143 with 95% CI [0.074, 0.219], and total effect, 0.132 with 95% CI [0.063, 0.209]. Its mediation effect was maintained regardless of statin intensity. Sensitivity analysis also provided a robustness of the results under potential existence of a confounder between HDL-cholesterol and CAC. This study suggests a potential causal pathway between statin and CAC (the positive association of statin on CAC) through HDL-cholesterol as an inhibitor.

Threat in the Company of Men: Ensemble Perception and Threat Evaluations of Groups Varying in Sex Ratio

Everyday, we visually perceive people not only in isolation but also in groups. Yet, visual person perception research typically focuses on inferences made about isolated individuals. By integrating social vision and visual ensemble coding, we present novel evidence that (a) perceivers rapidly (500 ms) extract a group’s ratio of men to women and (b) both explicit judgments of threat and indirect evaluative priming of threat increase as the ratio of men to women in a group increases. Furthermore, participants’ estimates of the number of men, and not perceived men’s coalition, mediate the relationship between the ratio of men to women and threat judgments. These findings demonstrate the remarkable efficiency of perceiving a group’s sex ratio and downstream evaluative inferences made from these percepts. Overall, this work advances person perception research into the novel domain of people perception, revealing how the visually perceived sex ratio of groups impacts social judgments.