Selection Bias Research Articles

Association of Changes in C-Reactive Protein Level Trajectories Through Early Adulthood With Cognitive Function at Midlife: The CARDIA Study.

Late-life inflammation has been linked to dementia risk and preclinical cognitive decline, but less is known about early adult inflammation and whether this could influence cognition in midlife. We aimed to identify inflammation levels through early adulthood and determine association of these trajectories with midlife cognition. We used data from the Coronary Artery Risk Development in Young Adults study to identify inflammation trajectories (C-reactive protein [CRP] level <10 mg/L) over 18 years through early adulthood (age range 24-58) in latent class analysis and to assess associations with cognition 5 years after the last CRP measurement (age range 47-63). Six cognitive domains were evaluated from tests of verbal memory, processing speed, executive function, verbal and category fluency, and global cognition; poor cognitive performance was defined as a decline of ≥1 SD less than the mean on each domain. The primary outcome was poor cognitive performance. Logistic regression was used to adjust for demographics, smoking, alcohol use, physical activity, and APOE 4 status. Among 2,364 participants, the mean (SD) age was 50.2 (3.5) years; 55% were female, and 57% were White. Three CRP trajectories emerged over 18 years: lower stable (45%), moderate/increasing (16%), and consistently higher (39%). Compared with lower stable CRP, both consistently higher (adjusted odds ratio [aOR] 1.67, 95% CI 1.23-2.26) and moderately/increasing (aOR 2.04, 95% CI 1.40-2.96) CRP had higher odds of poor processing speed; consistently higher CRP additionally had higher odds of poor executive function (aOR 1.36, 95% CI 1.00-1.88). For memory (moderately/increasing aOR 1.36, 95% CI 1.00-1.88; consistently higher aOR 1.18, 95% CI 0.90-1.54), letter fluency (moderately/increasing aOR 1.00, 95% CI 0.69-1.43; consistently higher aOR 1.05, 95% CI 0.80-1.39), category fluency (moderately/increasing aOR 1.16, 95% CI 0.82-1.63; consistently higher aOR 1.11, 95% CI 0.85-1.45), or global cognition (moderately/increasing aOR 1.16, 95% CI 0.82-1.63; consistently higher aOR 1.11, 95% CI 0.85-1.45), no association was observed. Consistently higher or moderate/increasing inflammation starting in early adulthood may lead to worse midlife executive function and processing speed. Study limitations include selection bias due to loss to follow-up and reliance on CRP as the only inflammatory marker. Inflammation is important for cognitive aging and may begin much earlier than previously known.

Efficacy of chemoradiotherapy in elderly patients with stage IV inoperable head and neck cancer.

This study aimed to compare the efficacy of chemoradiotherapy (CRT) with radiotherapy (RT) alone for elderly patients (≥ 65 years) with stage IV inoperable head and neck cancer (IV-HNC). Elderly patients diagnosed with inoperable IV-HNC from 2010 to 2015 were identified using the SEER database. Then, we performed a 1:1 propensity-score matched (PSM) analysis to reduce treatment selection bias, and the prognostic role of CRT was investigated using Kaplan-Meier analysis, log-rank test, and Cox proportional hazard models. The main outcome was overall survival (OS), and the secondary outcome was cancer-specific survival (CSS). A total of 3318 patients were enrolled, of whom 601 received RT alone and 2717 received CRT. Through PSM, 526 patients were successfully matched, and balances between the two treatment groups were reached. In the matched dataset, multivariable Cox analysis revealed that CRT was associated with better OS (HR = 0.580, P < 0.001) and CSS (HR = 0.586, P < 0.001). Meanwhile, subgroups of patients with IV-HNC (younger age, male sex, being married, black race, grade I-II, oral cavity site, T3-T4 stage, N0-N1 stage, M1 stage) were inclined to benefit more from CRT treatment. Furthermore, the survival benefit of CRT was more pronounced in patients aged 65 to 80 years, but was absent in patients aged 80 years or older. This study indicated that CRT resulted in better survival than RT alone in elderly patients with inoperable IV-HNC, especially for those subpopulations that benefit more from CRT treatment.

The molecular basis underlying T cell specificity towards citrullinated epitopes presented by HLA-DR4

CD4+ T cells recognising citrullinated self-epitopes presented by HLA-DRB1 bearing the shared susceptibility epitope (SE) are implicated in rheumatoid arthritis (RA). However, the underlying T cell receptor (TCR) determinants of epitope specificity towards distinct citrullinated peptide antigens, including vimentin-64cit59-71 and α-enolase-15cit10-22 remain unclear. Using HLA-DR4-tetramers, we examine the T cell repertoire in HLA-DR4 transgenic mice and observe biased TRAV6 TCR gene usage across these two citrullinated epitopes which matches with TCR bias previously observed towards the fibrinogen β−74cit69-81 epitope. Moreover, shared TRAV26-1 gene usage is evident in four α-enolase-15cit10-22 reactive T cells in three human samples. Crystal structures of mouse TRAV6+ and human TRAV26-1+ TCR-HLA-DR4 complexes presenting vimentin-64cit59-71 and α-enolase-15cit10-22, respectively, show three-way interactions between the TCR, SE, citrulline, and the basis for the biased selection of TRAV genes. Position 2 of the citrullinated epitope is a key determinant underpinning TCR specificity. Accordingly, we provide a molecular basis of TCR specificity towards citrullinated epitopes.

Using instruments for selection to adjust for selection bias in Mendelian randomization.

Selection bias is a common concern in epidemiologic studies. In the literature, selection bias is often viewed as a missing data problem. Popular approaches to adjust for bias due to missing data, such as inverse probability weighting, rely on the assumption that data are missing at random and can yield biased results if this assumption is violated. In observational studies with outcome data missing not at random, Heckman's sample selection model can be used to adjust for bias due to missing data. In this paper, we review Heckman's method and a similar approach proposed by Tchetgen Tchetgen and Wirth (2017). We then discuss how to apply these methods to Mendelian randomization analyses using individual-level data, with missing data for either the exposure or outcome or both. We explore whether genetic variants associated with participation can be used as instruments for selection. We then describe how to obtain missingness-adjusted Wald ratio, two-stage least squares and inverse variance weighted estimates. The two methods are evaluated and compared in simulations, with results suggesting that they can both mitigate selection bias but may yield parameter estimates with large standard errors in some settings. In an illustrative real-data application, we investigate the effects of body mass index on smoking using data from the Avon Longitudinal Study of Parents and Children.

Quantifying Lumbar Foraminal Volumetric Dimensions: Normative Data and Implications for Stenosis-Part 2 of a Comprehensive Series.

Lumbar foraminal stenosis (LFS) occurs primarily due to degenerative changes in older adults, affecting the spinal foramina and leading to nerve compression. Characterized by pain, numbness, and muscle weakness, LFS arises from structural changes in discs, joints, and ligaments, further complicated by factors like inflammation and spondylolisthesis. Diagnosis combines patient history, physical examination, and imaging, while management ranges from conservative treatment to surgical intervention, underscoring the need for a tailored approach. This multicenter study, conducted over six years at a tertiary hospital, analyzed the volumetric dimensions of lumbar foramina and their correlation with nerve structures in 500 patients without lumbar pathology. Utilizing high-resolution MRI with a standardized imaging protocol, eight experienced researchers independently reviewed the images for accurate measurements. The study emphasized quality control through the calibration of measurement tools, double data entry, validation checks, and comprehensive training for researchers. To ensure reliability, interobserver and intraobserver agreements were analyzed, with statistical significance determined by kappa statistics and the Student's t-test. Efforts to minimize bias included blinding observers to patient information and employing broad inclusion criteria to mitigate referral and selection biases. The methodology and findings aim to enhance the understanding of normal lumbar foramina anatomy and its implications for diagnosing and treating lumbar conditions. The study's volumetric analysis of lumbar foramina in 500 patients showed a progressive increase in foraminal volume from the L1/L2 to the L5/S1 levels, with significant enlargement at L5/S1 indicating anatomical and biomechanical complexity in the lumbar spine. Lateral asymmetry suggested further exploration. High interobserver and intraobserver agreement levels (ICC values of 0.91 and 0.95, respectively) demonstrated the reliability and reproducibility of measurements. The patient cohort comprised 58% males and 42% females, highlighting a balanced gender distribution. These findings underscore the importance of understanding foraminal volume variations for lumbar spinal health and pathology. Our study significantly advances spinal research by quantifying lumbar foraminal volumes, revealing a clear increase from the L1/L2 to the L5/S1 levels, indicative of the spine's adaptation to biomechanical stresses. This provides clinicians with a precise tool to differentiate between pathological narrowing and normal variations, enhancing the detection and treatment of lumbar foraminal stenosis. Despite limitations like its cross-sectional design, the strong agreement in measurements underscores the method's reliability, encouraging future research to further explore these findings' clinical implications.

Natural course of ulcerative colitis in China: Differences from the West?

Whether the natural course of ulcerative colitis (UC) in mainland China is similar or different from that in Western countries is unknown, and data on it is limited. We aimed to provide a comprehensive description of the natural course of UC in China and compare it with Western UC patients. Based on a prospective Chinese nationwide registry of consecutive patients with inflammatory bowel diseases, the medical treatments and natural history of UC were described in detail, including disease extension, surgery, and neoplasia. The Cox regression model was used to identify factors associated with poor outcomes. A total of 1081 UC patients were included with a median follow-up duration of 5.3years. The overall cumulative exposure was 99.1% to 5-aminosalicylic acids, 52.1% to corticosteroids, 25.6% to immunomodulators, and 15.4% to biologics. Disease extent at diagnosis was proctitis in 26.9%, left-sided colitis in 34.8%, and extensive colitis in 38.3%. Of 667 patients with proctitis and left-sided colitis, 380 (57.0%) experienced disease extent progression. A total of 58 (5.4%) UC patients underwent colectomy, demonstrating cumulative proportions of surgery at 1, 5, and 10years after diagnosis of 0.6%, 3.4%, and 8.2%, respectively. In addition, 23 (2.1%) UC patients were diagnosed with neoplasia, demonstrating cumulative proportions of neoplasia at 1, 5, and 10years after diagnosis of 0.5%, 1.0%, and 3.5%, respectively. Chinese UC patients had similar cumulative proportions of exposure to IBD-specific treatments but a lower surgical rate than patients in Western countries, indicating a different natural course, and close monitoring needs for UC in China. However, these results must be confirmed in population-based studies because the hospital-based cohort in our study might lead to selection bias.

Socioeconomic disparities in the postnatal growth of preterm infants: a systematic review.

To determine the effect of parental socioeconomic status (SES) on the postnatal growth of preterm infants. A systematic review (PROSPERO registration CRD42020225714) of original articles from Medline, Embase, CINAHL Plus and Web of Science published 1946-2023 was undertaken. Studies were included if they reported anthropometric growth outcomes for preterm infants according to parental SES. Data extraction and assessments of bias and health equity impact were conducted using custom-designed forms. A narrative synthesis of twelve included studies was performed. Most infants were moderate to late preterm. The settings, growth outcomes, timings of growth measurement, and SES measures were heterogenous. Six studies demonstrated an adverse effect of low parental SES on the extrauterine growth of preterm infants, five studies showed no effect, and one study showed a potentially beneficial effect. All studies had a high risk of bias, especially confounding and selection bias. The health equity impact of included studies was largely negative. Limited and low-quality evidence suggests that socioeconomic minoritisation may adversely impact the growth of preterm infants, thereby widening existing socioeconomic health inequities. Observational studies informed by theorisation of the mechanistic pathways linking socioeconomic minoritisation to adverse postnatal growth are required to identify targets for intervention. Limited evidence suggests low parental socioeconomic status (SES) adversely affects the postnatal growth of preterm infants across different settings. Early growth of preterm infants predicts neurodevelopmental outcomes and the risk of cardiovascular and metabolic disease in adulthood. Systematic screening of over 15,000 articles identified only twelve studies which reported postnatal growth outcomes for preterm infants according to parental SES. The health equity impact of the included studies was systematically assessed, and found to be negative overall. This study highlights limitations in existing evidence on the association between parental SES and postnatal growth, and delineates avenues for future research.

Involving different stakeholders in prioritising outcomes to assess healthcare systems response for type 1 diabetes management: Using co-creation approaches in Peru.

Engaging diverse stakeholders in developing core outcome sets (COSs) can produce more meaningful metrics as well as research responsive to patient needs. The most common COS prioritisation method, Delphi surveys, has limitations related to selection bias and participant understanding, while qualitative methods like group discussions are less frequently used. This study aims to test a co-creation approach to COS development for type 1 diabetes (T1DM) in Peru. Using a co-creation approach, we aimed to prioritise outcomes for T1DM management in Peru, incorporating perspectives from people with T1DM, caregivers, healthcare professionals, and decision-makers. A set of outcomes were previously identified through a systematic review and qualitative evidence synthesis. Through qualitative descriptive methods, including in-person workshops, each group of stakeholders contributed to the ranking of outcomes. Decision-makers also discussed the feasibility of measuring these outcomes within the Peruvian healthcare system. While priorities varied among participant groups, all underscored the significance of monitoring healthcare system functionality over mortality. Participants recognized the interconnected nature of healthcare system performance, clinical outcomes, self-management, and quality of life. When combining the rankings from all the groups, metrics related to economic impact on the individual and structural support, policies promoting health, and protecting those living with T1DM were deemed more important in comparison to measuring clinical outcomes. We present the first COS for T1DM focused on low-and-middle-income countriesand show aspects of care that are relevant in this setting. Diverse prioritisation among participant groups underscores the need of inclusive decision-making processes. By incorporating varied perspectives, healthcare systems can better address patient needs and enhance overall care quality.

Investigating the impact of housing price increases on consumption: heterogeneity by age, tenure and housing quality

PurposeThe purpose of this paper is to understand the distributional impact of house price increases on consumption in the context of the energy transition.Design/methodology/approachThis study draws from two micro cross-sectional datasets, the English Housing Survey (EHS) and the Living Costs and Food Survey (LCFS) to study the Marginal Propensity to Consume (MPC) out of changes in house prices. By employing pseudo-panel regressions, the paper examines the impact of house price changes on consumption among diverse household types.FindingsThis paper finds varying consumption responses to house price changes across age and tenure groups. Older homeowners tend to increase consumption when house prices rise. In contrast, middle-aged individuals, often renters or mortgage holders, reduce consumption in response to price increases. The youngest age group also experiences increased consumption but to a lesser degree than the oldest group. Energy-efficient homes are related to lower consumption across all tenure levels. However, when interacted with house prices and age, the estimates are positive, pointing to an unequal accrual of property premiums depending on housing market positions.Research limitations/implicationsThe main limitations stem from data constraints. First, using a pseudo-panel approach hinders control for unobservable selection bias. Additionally, while robust under cross-validation and specifications tests, the energy efficiency variable imputation results in a low number of energy-efficient homes. Due to heterogeneous responses to rising house prices, this paper contends that an energy transition model that subsidises homeowners’ renovation is likely to produce a negative impact on consumption among younger and middle-aged households.Originality/valueThis paper contributes to the MPC literature by incorporating energy efficiency as a key variable. It draws from recent data to obtain new estimates. By highlighting shifts in consumption patterns the paper contributes to a well-established body of literature with renewed policy relevance regarding housing retrofit.

Considerations for viral co-infection studies in human populations.

When respiratory viruses co-circulate in a population, individuals may be infected with multiple pathogens and experience possible virus-virus interactions, where concurrent or recent prior infection with one virus affects the infection process of another virus. While experimental studies have provided convincing evidence for within-host mechanisms of virus-virus interactions, evaluating evidence for viral interference or potentiation using population-level data has proven more difficult. Recent studies have quantified the prevalence of co-detections using populations drawn from clinical settings. Here, we focus on selection bias issues associated with this study design. We provide a quantitative account of the conditions under which selection bias arises in these studies, review previous attempts to address this bias, and propose unbiased study designs with sample size estimates needed to ascertain viral interference. We show that selection bias is expected in cross-sectional co-detection prevalence studies conducted in clinical settings, except under a strict set of assumptions regarding the relative probabilities of being included in a study limited to individuals with clinical disease under different viral states. Population-wide studies that collect samples from participants irrespective of their clinical status would meanwhile require large sample sizes to be sufficiently powered to detect viral interference, suggesting that a study's timing, inclusion criteria, and the expected magnitude of interference are instrumental in determining feasibility.

Trends and epidemiology in robotic-assisted total knee arthroplasty: Reduced complications and shorter hospital stays.

This study provides an in-depth analysis of the immediate postoperative outcomes and implications or robotic-assisted total knee arthroplasty (RA-TKA) compared with conventional TKA (C-TKA), particularly with regard to mortality, complications, hospital stay and costs, drawing from a comprehensive nationwide data set. The Nationwide Inpatient Sample (NIS) database, the largest all-payer inpatient healthcare database in the United States, was used to identify all patients who underwent RA-TKA or C-TKA from 2016 to 2019. A total of 527,376 cases, representing 2,638,679 patients who underwent elective TKA were identified, of which 88,415 had RA-TKA. To mitigate potential variations and selection bias in baseline characteristics between the two groups, a propensity score-matched analysis was employed to further balance and refine our data set, resulting in 176,830 patients evenly distributed between the groups. Analysis was performed according to demographics, immediate post-operative complications, and economic data, including payor class, length of stay and total charges. There was a marked shift towards RA-TKA, from an initial 0.70% in 2016 to a notable 7.30% by 2019. Patients who underwent RA-TKA were slightly younger (66.2 ± SD years), compared to the C-TKA group (66.7 ± SD years). Hospital stay was 1.89 days and 2.29 days for RA-TKA and C-TKA, respectively. Charges metrics revealed slightly higher charges for RA-TKA. Less postoperative complications were found in the RA-TKA group, such as blood loss, anaemia, acute kidney injury, venous thromboembolism, pulmonary embolism, pneumonia and surgical wound complication. Even following the propensity score matching, these findings remained consistent and statistically significant. RA-TKA use in the United States has grown substantially in the last few years and has been associated with significantly reduced immediate post-operative complications and length of hospital stay compared to C-TKA, offering safer surgical management for TKA patients. Further studies on the short- and long-term outcomes of RA-TKA would improve the understanding of the full potential of this technology. Level III.

Stochastic method based on copulas for predicting severe road traffic interactions

A major difficulty in assessing road traffic safety is the scarcity of historical accident data. xxThis is a common problem in contexts where a certain level of safety has been reached or where exposure is low, such as mixed traffic conditions with different levels of transport automation. Recent studies have demonstrated how severe interactions between road users and/or road users and infrastructure can be a direct measure of safety. However, limiting the investigation to only the most extreme events may lead to inconclusive results considering the lack of prediction robustness and the possible selection bias. In this context, extreme value theory (EVT) is commonly used to extrapolate crashes from road traffic interactions, even combining several indicators. The present work extends the EVT paradigm by proposing a method based on copula functions and EVT, which enables a more specific and continuous evaluation of interaction severity. Compared with pure EVT, this new approach extends the boundary to interactions of all severities while implicitly assuming that the relationship between safety-relevant events and road casualties is stochastic. This EVT-copula approach was also compared with bivariate peaks over threshold (BPOT). It was found that the two approaches yield similar prediction results for crash probabilities. Furthermore, the proposed approach applies to events not properly defined in BPOT and provides more accurate predictions for severe (and less severe) interactions compared with BPOT, when benchmarked against observations.

The Relationship between Thyroid Hormones and Insulin Resistance in Polycystic Ovary Syndrome Women.

This study aimed to investigate the changes in thyroid hormones in the serum of patients with polycystic ovary syndrome (PCOS) and their correlation with insulin resistance. This is a retrospective study. 84 patients having insulin resistance and 76 patients without insulin resistance were included. 90 women without history of PCOS were selected as a healthy control group. This study was conducted at Shijiazhuang Fourth Hospital. Blood samples were collected from each group on days 3-5 of their menstrual cycle, and their triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) levels were analyzed and compared between groups. We investigated the changes of serum thyroid hormones in patients with PCOS and their correlation with insulin resistance. We found that serum levels of T3 and T4 were significantly decreased, while TSH levels were significantly increased in PCOS patients compared with HCs. Moreover, we found that patients with insulin resistance had significantly lower levels of serum T3 and T4 and higher levels of TSH compared to those PCOS participants without insulin resistance. This study was a retrospective and single-center study, which had selection bias, information bias, and confounding variables may affect the accuracy and reliability of the conclusion. Insulin resistance negative correlates with their serum T3, T4, and positive correlates with their TSH levels. Our results develop a combined test model with the serum T3, T4, and TSH levels for the clinical diagnosis of insulin resistance in PCOS women.

Oncological survival in pancreatic head ductal carcinoma: hybrid minimally invasive versus open pancreatoduodenectomy - a single centre analysis.

Surgery remains the only curative treatment option for pancreatic head cancer. Laparoscopic surgical techniques are increasingly used, in line with the development of visceral surgery as a whole. The success of surgery is measured by the oncological outcome. Aim of this study is to evaluate the oncological outcome and survival after laparoscopic assisted resection of the pancreatic head compared to open surgery for ductal adenocarcinoma. Data were collected in a prospectively maintained database. Perioperative and oncological outcomes of 182 laparoscopic pancreatic head resections for ductal carcinoma were compared with 585 open pancreatic head resections. The laparoscopic procedures were performed between 2010 and 2022, the open procedures between 2002 and 2022. Laparoscopic procedure was significantly superior in terms of intraoperative blood loss (575 vs. 600mL, P=0.021) and operative time (413 vs. 427 min, P=0.033). Tumour size (25 vs. 27mm, P=0.028), need for portal vein resection (P=0.009) and blood transfusion (P=0.004) were significantly greater in the open group (P=0.009). The resection margin remained negative significantly more often in the laparoscopic group (159 [87%] vs. 449 [77%], P<0.001). There was no difference in postoperative mortality and morbidity. Postoperative survival at 5 years was significantly better in the laparoscopic group (37% vs. 15%, P<0.001). In our cohort, patients who underwent hybrid laparoscopic resection of pancreatic head cancer showed a significantly improved oncological outcome. Most of these effects are due to selection bias, which is not captured by the clinical parameters used to date. Our results highlight the need for additional prognostic factors in pancreatic cancer.

R&amp;D Subsidies in Spain: are they Really Useful?

AbstractThis article is aimed at estimating the impact of R&amp;D subsidies on the demand for researchers, using information provided by a panel of Spanish firms belonging to the industrial and services sectors followed up during the 2004–2016 period. Estimates include corrections for the endogeneity bias generated by wages and by a set of variables measuring R&amp;D public financing, as well as for the sample selection bias coming from the fact that the only wage data available are those from firms that are internal R&amp;D performers and hire researchers. Estimate results show that public R&amp;D financing has a positive and relevant impact on the demand for researchers. This result allows supporting the implementation of policies to promote public research funding in Spain, regardless of the origin of the funds received.

Examining the minimal combined effects of gender and minoritized racial/ethnic identity among academic entrepreneurs

PurposeThis study examined differences related to gender and racial/ethnic identity among academic researchers participating in the National Science Foundation’s “Innovation-Corps” (NSF I-Corps) entrepreneurship training program. Drawing from prior research in the fields of technology entrepreneurship and science, technology, engineering and mathematics (STEM) education, this study addresses the goal of broadening participation in academic entrepreneurship.Design/methodology/approachUsing ANOVA and MANOVA analyses, we tested for differences by gender and minoritized racial/ethnic identity for four variables considered pertinent to successful program outcomes: (1) prior entrepreneurial experience, (2) perceptions of instructional climate, (3) quality of project team interactions and (4) future entrepreneurial intention. The sample includes faculty (n = 434) and graduate students (n = 406) who completed pre- and post-course surveys related to a seven-week nationwide training program.FindingsThe findings show that group differences based on minoritized racial/ethnic identity compared with majority group identity were largely not evident. Previous research findings were replicated for only one variable, indicating that women report lower amounts of total prior entrepreneurial experience than men, but no gender differences were found for other study variables.Originality/valueOur analyses respond to repeated calls for research in the fields of entrepreneurship and STEM education to simultaneously examine intersecting minoritized and/or under-represented social identities to inform recruitment and retention efforts. The unique and large I-Corps national dataset offered the statistical power to quantitatively test for differences between identity groups. We discuss the implications of the inconsistencies in our analyses with prior findings, such as the need to consider selection bias.

Vaping Transitions and Incident Depressive Symptoms among Young Adults: A Marginal Structural Model Analysis.

The extent to which vaping influences depression is unclear, but could be estimated through application of novel epidemiologic methods. Among a prospective cohort of young adults from California who screened negative for depression, we estimated repeated measures marginal structural models to examine the association of four vaping transitions from time T to T+1 (persistent use, discontinuation, initiation, persistent nonuse) with risk of clinically significant depressive symptoms at T+1, simultaneously across three ~1.5 year time-intervals between 2017-2021. Stabilized inverse probability of treatment and censoring weights adjusted for time-dependent confounders and selection bias. Among n=3,496 observations (1,806 participants, mean pooled baseline age=19.5), 8.1% reported persistent vaping from T to T+1, 6.2% reported discontinuation (i.e., use at T and no use at T+1), 6.5% initiated e-cigarettes (i.e., no use at T and use at T+1), and 79.2% reported persistent nonuse at both time-points. Compared to persistent vaping at two waves, persistent nonuse (RR=0.76, 95%CI:0.62-0.93) and discontinuation (RR=0.71, 95%CI:0.52-0.96) were associated with lower risk of depression. Associations were robust to sensitivity analyses, including restricting to tobacco naïve participants and varying temporal assumptions to reduce potential for reverse causation. Young adults who consistently avoid or discontinue vaping may be protected from depressive symptom occurrence.

Long-term Outcome After Surgical Resection of Paraaortic Lymph Node Metastasis of Colorectal Cancer: A Multicenter Retrospective Study.

The significance of resection of paraaortic lymph node metastasis in colorectal cancer is controversial. To clarify the prognosis of colorectal cancer after paraaortic lymph node metastasis resection. Multicenter retrospective study. Thirty-six institutions in Japan participated in this study. Patients with resected and pathologically proven paraaortic lymph node metastasis of CRC between 2010 and 2015. Database and medical records at each institution. Overall survival after paraaortic lymph node metastasis resection, recurrence-free survival, and recurrence patterns after R0 resection of paraaortic lymph node metastasis. A total of 133 patients were included in the primary analysis population in this study. The 5-year overall survival rate (95% confidence interval [CI]) was 41.0% (32.0, 49.8), and the median survival (95% CI) was 4.1 (3.4, 4.7) years. Independent prognostic factors for overall survival were the pathological T stage (pT4 vs. pT1- 3, adjusted hazard ratio [aHR]: 1.91, p = 0.006), other organ metastasis (present vs. absent, aHR: 1.98, p = 0.005), time to metastases (synchronous vs. metachronous, aHR: 2.02, p = 0.02), and number of paraaortic lymph node metastasis (≥3 vs. <3, aHR: 2.13, p = 0.001). The 5-year recurrence-free survival rate (95% CI) was 21.1% (13.5, 29.7), with a median (95% CI) of 1.2 (0.9, 1.4) years. The primary tumor location (left- vs. right-sided colon, aHR: 4.77, p = 0.01; rectum vs. right-sided colon, aHR: 5.27, p = 0.006), other organ metastasis (present vs. absent, aHR: 1.90, p = 0.03), number of paraaortic lymph node metastasis (≥3 vs. <3, aHR: 2.20, p = 0.001), and hospital volume (<10 vs. ≥10, aHR: 2.18, p = 0.02) were identified as independent prognostic factors for recurrence-free survival. Paraaortic lymph node recurrence was the most common at 33.3%. Selection bias cannot be ruled out because of the retrospective nature of the study. Less than three paraaortic lymph node metastasis was a favorable prognostic factor for both overall survival and recurrence-free survival. However, paraaortic lymph node metastases were considered to be a systemic disease and the significance of resection was limited. See Video Abstract.

Application of information from external data to correct for collider bias in a Covid-19 hospitalised cohort

BackgroundThroughout the Covid-19 pandemic, researchers have made use of electronic health records to research this disease in a rapidly evolving environment of questions and discoveries. These studies are prone to collider bias as they restrict the population of Covid-19 patients to only those with severe disease. Inverse probability weighting is typically used to correct for this bias but requires information from the unrestricted population. Using electronic health records from a South London NHS trust, this work demonstrates a method to correct for collider bias using externally sourced data while examining the relationship between minority ethnicities and poor Covid-19 outcomes.MethodsThe probability of inclusion within the observed hospitalised cohort was modelled based on estimates from published national data. The model described the relationship between patient ethnicity, hospitalisation, and death due to Covid-19 – a relationship suggested to be susceptible to collider bias. The obtained probabilities (as applied to the observed patient cohort) were used as inverse probability weights in survival analysis examining ethnicity (and covariates) as a risk factor for death due to Covid-19.ResultsWithin the observed cohort, unweighted analysis of survival suggested a reduced risk of death in those of Black ethnicity – differing from the published literature. Applying inverse probability weights to this analysis amended this aberrant result to one more compatible with the literature. This effect was consistent when the analysis was applied to patients within only the first wave of Covid-19 and across two waves of Covid-19 and was robust against adjustments to the modelled relationship between hospitalisation, patient ethnicity, and death due to Covid-19 made as part of a sensitivity analysis.ConclusionsIn conclusion, this analysis demonstrates the feasibility of using external publications to correct for collider bias (or other forms of selection bias) induced by the restriction of a population to a hospitalised cohort using an example from the recent Covid-19 pandemic.

Vulnerability, Resilience and Adaptation of Lagos Coastal Communities to Flooding

Lagos has been identified as one of the 50 cities most vulnerable to extreme sea levels. The state also ranked 30th among 136 port cities in terms of population exposure to flooding under a past climate scenario (2005) and 15th under a future climate scenario (2070s). The state faces significant environmental strains as a result of its geo-economic status. Some of the problems are wetland loss, pollution, population pressure, restricted access to drinkable water, and flooding. All these factors have contributed to the instability of Lagos ecosystems, but the impact of flooding is particularly significant because Lagos is surrounded by aquatic ecosystems and its low elevation and topography increase its susceptibility to flooding. The method adopted in this review involved the use of PICO (Population, Intervention, Control, and Outcomes) criteria to synthesize the research questions and objectives. Thereafter, PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines was employed for the study selection criteria, search strategies and data extraction methods. A broad search strategy involving databases (Google scholar, Science Direct), pertinent keywords and search filters was used to identify relevant articles and minimize selection bias. After the search, PICO criteria was again used to select the studies to be considered in the review. The selected text were downloaded and the essential scientific information were extracted and analyzed in the study. The impacts of flooding are numerous. Flooding is a key factors that has prevented Africa’s growing urban population from escaping poverty, and it also impedes the achievement of some SDGs. This is because many African cities lack the resources and infrastructures needed to withstand extreme weather conditions. Surviving in flood-prone cities like Lagos is a daunting task because flood affects livelihood, human health, and can even cause death. Specifically, the 2020 flood incidence in Nigeria affected about 40% of the local government areas, and 97% of the states, displacing over 120,000 persons and killing 68 persons aside from properties and farmlands destroyed. Women and children are the most vulnerable. The adoption of advanced flood risk management strategies could help in flood containment and management in the state.