Random Effects Regression Models Research Articles

CSR associations and market value: the moderating role of market competition

Purpose This paper aims to study the impact of consumers’ corporate social responsibility (CSR) associations on corporate financial performance and the moderating role of market competition. Design/methodology/approach The panel data set is analyzed using a random effects regression model. The analyzed data is based on the unique RepZ Responsibility scores published by the global research agency Kantar Millward Brown and contains information about consumer CSR associations. Findings This study reveals CSR associations' positive, lagged, direct impact on firms’ market value. Market competition moderates this relationship in the way that a company’s market value benefits more from consumers' CSR associations when facing high rather than low market competition. Practical implications Consumers' CSR perceptions increase the market value of a company. This effect is intensified when brands are exposed to intense competition, which allows conclusions about CSR as a differentiation strategy to be drawn: To stand out in a competitive market, brands should prioritize improving their CSR associations among consumers to differentiate themselves and increase their market value. Originality/value To the best of the authors’ knowledge, this study is the first to test the effect of consumers’ CSR associations on forward-looking financial performance measures. Moreover, by analyzing the moderating effect of market competition on the relationship between CSR associations and firms' market value, this study provides information about the differentiating power of CSR from a brand perspective using a panel-data analysis.

From commitment to capital: does environmental innovation reduce corporate cash holdings?

ABSTRACT Using 7066 firm-year observations of the US-listed firms for the period of 2008–2021, we examine a channel through which eco-innovation affects Corporate Cash holding. More specifically, we modeled the role of goodwill between eco-innovation and Corporate Cash holding. Using a random effect regression model, we show the economically relevant and statistically significant negative impact of eco-innovation on firm-level cash holdings. We provide evidence that goodwill fully mediates the relationship between eco-innovation and cash holdings. Our analyses further document that the impact of eco-innovation on firm-level cash holdings is more pronounced for the firms that operate in environmentally insensitive industries. The influence of eco-innovation on cash holdings is less for low-size firms relative to the high size and more for highly leveraged firms. The results are robust for alternative measures of eco-innovation, selection biases and potential endogeneity. The findings have imperative implications for stakeholders’ engagement from a social capital perspective.

Statistics in Phonetics

Phonetics is the scientific field concerned with the study of how speech is produced, heard, and perceived. It abounds with data, such as acoustic speech recordings, neuroimaging data, or articulatory data. In this article, we provide an introduction to different areas of phonetics (acoustic phonetics, sociophonetics, speech perception, articulatory phonetics, speech inversion, sound change, and speech technology), an overview of the statistical methods for analyzing their data, and an introduction to the signal processing methods commonly applied to speech recordings. A major transition in the statistical modeling of phonetic data has been the shift from fixed effects to random effects regression models, the modeling of curve data (for instance, via generalized additive mixed models or functional data analysis methods), and the use of Bayesian methods. This shift has been driven in part by the increased focus on large speech corpora in phonetics, which has arisen from machine learning methods such as forced alignment. We conclude by identifying opportunities for future research.

Are social protection and food security accelerators for adolescents to achieve the Global AIDS targets?

Without effective, scalable interventions, we will fail to achieve the Global AIDS Targets of zero AIDS-related deaths, zero HIV transmission and zero discrimination. This study examines associations of social protection and food security among adolescents living with HIV (ALHIV), with three Global AIDS Targets aligned outcomes: antiretroviral treatment (ART) adherence and viral suppression, HIV transmission risk behaviour and enacted stigma. We conducted three study visits over 2014-2018 with 1046 ALHIV in South Africa's Eastern Cape province. Standardized surveys provided information on receipt of government-provided cash transfers and past-week food security, alongside self-reported ART adherence, sexual debut and condom use, and enacted HIV-related stigma. Viral load (VL) data was obtained through data extraction from patient files and linkage with National Health Laboratory Service test results (2014-2020). We used a multivariable random-effects regression model to estimate associations between receiving government cash transfers and food security and three outcomes: ART adherence and viral suppression, delayed sexual debut or consistent condom use and no enacted stigma. We tested moderation by sex and age and fitted disaggregated models for each outcome. Among the 933 ALHIV completing all three study visits, 55% were female, and the mean age was 13.6 years at baseline. Household receipt of a government cash transfer was associated with improvements on all outcomes: ART adherence and viral suppression (aOR 2.03, 95% CI 1.29-3.19), delayed sexual debut or consistent condom use (aOR 1.62, 95% CI 1.16-2.27) and no enacted stigma(aOR 2.33, 95% CI 1.39-3.89). Food security was associated with improvements on all outcomes: ART adherence and viral suppression (aOR 1.73, 95% CI 1.30-2.30), delayed sexual debut or consistent condom use (aOR 1.30, 95% CI 1.03-1.64) and no enacted stigma (aOR 1.91, 95% CI 1.32-2.76). Receiving both cash transfers and food security increased the probability of ART adherence and VL suppression from 36% to 60%; delayed sexual debut or consistent condom use from 67% to 81%; and no enacted stigma from 84% to 96%. Government-provided cash transfers and food security, individually and in combination, are associated with improved outcomes for ALHIV aligned with Global AIDS Targets. They may be important, and underutilized, accelerators for achieving these targets.

Human Resource Accounting and Share Price Performance Evidence from Listed Insurance Firms in Nigeria

This study investigates the impact of Human Resource Accounting (HRA) on share price performance among listed insurance firms in Nigeria. Specifically, the study examines the effects of human capital efficiency, structural capital efficiency, capital employed efficiency, and the value-added intellectual capital coefficient (VAIC) on share price performance. This research adopts ex-post facto and descriptive research designs, utilizing data from 13 insurance firms listed on the Nigerian Exchange Group from 2012 to 2021. Random effect regression model was employed to address statistical issues ensuring robust results, after controlling for multicollinearity and heteroscedasticity. The findings reveal that human capital efficiency and capital employed efficiency significantly enhance share price performance, highlighting the importance of these factors in driving market valuation. Conversely, VAIC shows a significant negative impact on share price performance, suggesting that not all aspects of intellectual capital positively influence market outcomes in the insurance sector. These results contribute to a deeper understanding of how human resource investments affect financial performance, particularly in the context of emerging markets like Nigeria. Based on these findings, this study recommends among others that insurance firms should prioritize investments in human capital development through targeted training and continuous professional development. This approach will enhance employee productivity and innovation, which in turn would positively influence share price performance and contribute to the overall financial health and market competitiveness of the firm.

Subjective Well-Being of Parents and Childless People in Older Age in Germany

AbstractThe growing number of older childless individuals in Western societies has raised concerns about their subjective well-being. In this study, we scrutinize the subjective well-being of parents and childless individuals aged 60 years and older. We examine subjective well-being as a multi-dimensional construct encompassing life satisfaction, positive affect, and negative affect. Based on the value-of-children approach, we hypothesize that childless individuals experience lower subjective well-being than parents and that the disparity in well-being differs with age, gender, and the quality of the parent-child relationship. For our analysis, we use data from a nationally representative sample of adults aged 60 years and older (n = 10,682) drawn from the German Ageing Survey. Our findings from random effects regression models show that childless individuals report lower life satisfaction, less positive affect, and more negative affect than parents. These associations are larger for men than for women but do not vary significantly across age groups. Furthermore, our results suggest that the benefits of parenthood strongly depend on the quality of the parent-child relationship. Childless people report lower subjective well-being than parents with a close emotional bond with their children, but similar or even higher subjective well-being than parents with an emotionally distant parent-child relationship. In sum, our study indicates that childless people experience, on average, lower well-being across all three dimensions of subjective well-being in older age. However, under specific circumstances, childless individuals may fare better than parents.

Special Issue on Informatics Education: ChatGPT Performs Worse on USMLE-Style Ethics Questions Compared to Medical Knowledge Questions.

The main objective of this study is to evaluate the ability of the Large Language Model ChatGPT to accurately answer USMLE board style medical ethics questions compared to medical knowledge based questions. This study has the additional objectives of comparing the overall accuracy of GPT-3.5 to GPT-4 and to assess the variability of responses given by each version. Using AMBOSS, a third party USMLE Step Exam test prep service, we selected one group of 27 medical ethics questions and a second group of 27 medical knowledge questions matched on question difficulty for medical students. We ran 30 trials asking these questions on GPT-3.5 and GPT-4, and recorded the output. A random-effects linear probability regression model evaluated accuracy, and a Shannon entropy calculation evaluated response variation. Both versions of ChatGPT demonstrated a worse performance on medical ethics questions compared to medical knowledge questions. GPT-4 performed 18% points (P < 0.05) worse on medical ethics questions compared to medical knowledge questions and GPT-3.5 performed 7% points (P = 0.41) worse. GPT-4 outperformed GPT-3.5 by 22% points (P < 0.001) on medical ethics and 33% points (P < 0.001) on medical knowledge. GPT-4 also exhibited an overall lower Shannon entropy for medical ethics and medical knowledge questions (0.21 and 0.11, respectively) than GPT-3.5 (0.59 and 0.55) which indicates lower variability in response. Both versions of ChatGPT performed more poorly on medical ethics questions compared to medical knowledge questions. GPT-4 significantly outperformed GPT-3.5 on overall accuracy and exhibited a significantly lower response variability in answer choices. This underscores the need for ongoing assessment of ChatGPT versions for medical education. ChatGPT, Large Language Model, Artificial Intelligence, Medical Education, USMLE, Ethics.

Blocked Pipes: The Economic Consequence of Skilled Worker Shortages

The thinning of the supply of skilled labor is having major negative implications on the economy. This research explores the “skilled labor gap” by examining the plumbing industry and quantifying the economic value lost through inefficiencies and labor premiums. The analysis utilizes state-level panel data for the years 2010 to 2018, employing both a linear OLS model of pooled data and a random effects regression model to determine the relationship between the number of plumbers and the price of plumbing services (proxied in plumber wages). Price effects are modeled across industries to determine the effects on the overall economy.

Police personnel allocation and homicide clearance

PurposeThis paper applies novel techniques from the field of operations management to examine the allocation of patrol and investigative personnel to identify which is most effective in improving police performance around homicide clearance.Design/methodology/approachA panel sample of homicide clearance rates from the 100 largest US cities between 2000 and 2013 were analyzed in two steps: first, a random-effects regression model was performed to locate influential factors; second, optimum analysis was applied to locate the optimal values that yield maximal homicide clearance.FindingsBoth patrol and investigative personnel levels have a significant impact on homicide clearance. Maximal clearance can be achieved by allocating departmental personnel to investigative roles.Research limitations/implicationsGiven recent trends around “defunding” police and public sector austerity measures, future research should continue to explore the utility of optimum analysis for efficient allocation of policing personnel.Originality/valueThis study provides proof of concept for the use of optimum analysis in policing research.

The effects of geographical and business proximity on affiliates’ R&amp;D investment: a proximity theory perspective

Purpose This study aims to examine the impact of geographical and business proximity between parent companies and affiliates on R&amp;D investments in business groups. Furthermore, it compares the moderating effect of value chain participants’ bargaining power and the performance-aspiration gap. Design/methodology/approach This study uses data from 411 Chinese private manufacturing listed firms affiliated with business groups. This paper conducts regression analysis using Stata 16.0 software. Additionally, this paper employs combined random effects regression models, the 2SLS method and GMM method. Findings Geographical distance between focal affiliates and parent companies is negatively related to focal affiliates’ R&amp;D. The higher the business proximity between focal affiliates and parent companies, the more R&amp;D investments are made. Further research shows that with stronger bargaining power and a wider performance-aspiration gap, the negative relationship between geographical distance and R&amp;D investment weakens. Originality/value This study contributes to the R&amp;D investment literature by offering a novel perspective on why proximity influences affiliates’ R&amp;D investments in Chinese business groups. This study enriches the proximity theory by introducing business proximity as a new dimension into the framework. Furthermore, this study highlights the boundary conditions of the proximity theory by ascertaining the moderating effects of bargaining power and the performance-aspiration gap.

Potential efficacy of digital polymerase chain reaction for non-invasive prenatal screening of autosomal aneuploidies: a systematic review and meta-analysis

BackgroundDigital Polymerase Chain Reaction (dPCR) presents a promising approach for quantifying DNA and analyzing copy number variants, particularly in non-invasive prenatal testing. This method offers a streamlined and time-efficient procedure in contrast to the widely used next-generation sequencing for non-invasive prenatal testing. Studies have reported encouraging results for dPCR in detecting fetal autosomal aneuploidies. Consequently, this systematic review aimed to evaluate the effectiveness of dPCR in screening for trisomy 21, 18, and 13.MethodsA systematic search was conducted in PubMed, Web of Sciences, and Embase for relevant articles published up to December 30, 2023. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was utilized for the quality assessment of the included articles. Furthermore, a bivariate random-effect regression model was used to conduct a meta-analysis on the utility of dPCR for trisomy 21 screening.ResultsA total of 9 articles were included in this review, with all of them assessing the utility of dPCR in trisomy 21 screening, and 2 and 1 studies conducting additional analysis on the screening abilities of dPCR for trisomy 18 and 13, respectively. A bivariate random-effects model calculated pooled sensitivity and specificity with a 95% confidence interval (CI). Meta-analysis of 6 studies comparing trisomy-21 screening with karyotyping demonstrated dPCR's pooled sensitivity of 98% [95% CI: 94 -100] and specificity of 99% [95% CI: 99 -100]. While conducting a meta-analysis for trisomy 13 and 18 proved impractical, reported values for sensitivity and specificity were favorable.ConclusionsThese findings suggest that dPCR holds promise as an effective tool for non-invasive prenatal testing, presenting a less time-consuming and intricate alternative to next-generation sequencing. However, further research is necessary to evaluate dPCR's applicability in clinical settings and to delineate its specific advantages over next-generation sequencing. This study contributes valuable insights into the potential of dPCR for enhancing prenatal screening methodologies.Trial registrationThe protocol of this study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) on 7/3/2024, with a registration code of CRD42024517523.

The relation between reading and externalizing behavior: a correlational meta-analysis

Reading proficiency is important because it has life-long consequences and influences success in other academic areas. Many students with behavior problems are poor readers and many students with learning disabilities have more behavior problems than their typical peers. We conducted a correlational meta-analysis to examine the association between reading and externalizing behavior in students ages 5–12. We identified 33 studies that reported 88 effect sizes. Using a random-effects linear regression model with robust variance estimation, we found a significant, negative correlation (r= −0.1698, SE = 0.01, p < 0.0001) between reading and externalizing behavior. We tested several moderators related to measurement and sample characteristics. We found that rater type, behavior dimension (e.g., aggression), time between longitudinal measurement points, age of the sample, and percentage male of the sample moderated the relation between reading and behavior. Whether the reading assessment measured comprehension or word reading and socioeconomic status of the sample did not moderate the relation. Understanding the association between reading and externalizing behavior has implications for disability identification and intervention practices for children in elementary school. Future research should examine shared cognitive factors and environmental influences that explain the relation between the constructs.

Tramadol use in U.S. Adults With Commercial Health Insurance, 2005–2021

IntroductionTramadol has been associated with chronic opioid use and emergency room (ER) visits. However, little is known about trends in prescription tramadol use in the US. MethodsOptum's de-identified Clinformatics® Data Mart Database was used to assess trends in monthly incident and prevalent tramadol use from 2005 to 2021, stratified by sex and age (18-64 vs. ≥65 years). State-specific trends following scheduling of tramadol as Class IV controlled substance in August 2014 were analyzed with random effects regression models. Demographics, comorbidities, initiation setting, dose, and co-dispensing with other opioids and central nervous system (CNS) agents were assessed in people initiating tramadol, stratified by age and initiation year (2005-2010, 2011-2015, 2016-2021). Analyses were performed in 2023 and 2024. ResultsDuring 2005-2021, the mean percentage using tramadol in a given month was 0.88% of younger females, 0.55% of younger males, 1.97% of older females, and 1.14% of older males; 5,729,652 initiations were identified. Since 2014, estimated relative yearly decrease was 4% (95% CI 3%; 5%) in use and 5% (95% CI 4%; 5%) in initiation, with variation across states. Primary care percentage of tramadol initiations declined from 49.2% in 2005-2010 to 37.2% in 2016-2021. During 2016-2021, co-dispensing with other CNS agents occurred in 37.8% of younger and 32.1% of older adults initiating tramadol. ConclusionsTramadol use was higher in females and older adults, exhibited heterogeneous trends across states, and shifted from primary care to ER and specialist settings over time. Co-dispensing with other CNS agents was common and warrants further monitoring.

The Competitiveness of Moroccan Export and its Determinants

This research encompasses two distinct parts. The first phase involves assessing the industries in which Moroccan exports demonstrate a comparative advantage from 2002 to 2022, utilizing the Revealed Comparative Advantage (RCA) index. To achieve this, data on Moroccan exports and world exports for different industries are collected, incorporating detailed information on product categories and trade volumes. The RCA index, as developed by Balassa (1965), has been computed using these datasets, and a comparative analysis has been performed to determine industries where Morocco enjoys a comparative advantage (Balassa, 1965). Our RCA analysis sorted out a categorization of 3 three different set of industries, distinguishing between industries with high RCA values ensuring sustained competitiveness, emerging sectoral potentials with increasing RCA values, and finally industries facing challenges with declining or fluctuating RCA values. The second part of the thesis employs a robust empirical analysis, employing panel data models and statistical tests, shedding light on the intricate dynamics shaping export competitiveness in Morocco. The amalgamation of these two components contributes to a holistic understanding of the subject, presenting policymakers and researchers with nuanced insights. In this empirical study, we investigate the determinants of export competitiveness in Moroccan industries. Employing a panel data approach, our research model encompasses key variables, including the Revealed Comparative Advantage (RCA) index as the dependent variable. Initially focusing on the Fixed Effects (FE) regression model, our analysis reveals nuanced relationships between these variables. Subsequently, we integrate insights from the Random Effects (RE) regression model, the Panel Effects (PE) regression model. Results shed light on the intricate dynamics shaping export competitiveness in Morocco. Drawing on existing literature and cross-referencing, this study contributes to the broader understanding of economic growth and trade dynamics, providing valuable insights for policymakers and researchers alike.

Multicentre, retrospective cohort study protocol to identify racial and ethnic differences in acute kidney injuries in children and adolescents with diabetic ketoacidosis

IntroductionApproximately 40% of children with diabetic ketoacidosis (DKA) develop acute kidney injury (AKI), which increases the risk of chronic kidney damage. At present, there is limited knowledge of racial or...

Patterns of national emergency department utilization by fee-for-service Medicare beneficiaries with dementia.

Individuals with Alzheimer's disease and related dementias (ADRD) often face high acute care clinical utilization and costs with unclear benefits in survival or quality of life. The emergency department (ED) is frequently the site of pivotal decisions in these acute care episodes. This study uses national Medicare data to explore this population's ED utilization. Retrospective cohort study of persons aged ≥66 years enrolled in traditional Medicare with a Chronic Condition Warehouse diagnosis of dementia. Primary 1-year outcome measures included ED visits with and without hospitalization, ED visits per 100 days alive, and health-care costs. A multivariate random effects regression model (clustered by county of residence), adjusted for sociodemographics and comorbidities, examined how place of care on January 1, 2018, was associated with subsequent ED utilization. In 2018, 2,680,006 ADRD traditional Medicare patients (mean age 82.9, 64.2% female, 9.4% Black, 6.2% Hispanic) experienced a total of 3,234,767 ED visits. Over half (52.2%) of the cohort experienced one ED visit, 15.5% experienced three or more, and 37.1% of ED visits resulted in hospitalization. Compared with ADRD patients residing at home without services, the marginal difference in ED visits per 100 days alive varied by location of care. Highest differences were observed for those with hospitalizations (0.48 visits per 100 days alive, 95% confidence interval [CI] 0.47-0.49), skilled nursing facility (rehab/skilled nursing facility [SNF]) stays (0.27, 95% CI 0.27-0.28), home health stays (0.25, 95% CI 0.25-0.26), or observation stays (0.82, 95% CI 0.77-0.87). Similar patterns were observed with ED use without hospitalization and health-care costs. Persons with ADRD frequently use the ED-particularly those with recent hospitalizations, rehab/SNF stays, or home health use-and may benefit from targeted interventions during or before the ED encounters to reduce avoidable utilization and ensure goal-concordant care.

Safety profiles of offspring born from early-follicular long-acting GnRH agonist protocol and daily mid-luteal GnRH agonist protocol: a retrospective study

BackgroundThe gonadotropin hormone-releasing hormone agonists (GnRH-a) have been widely used for controlled ovarian stimulation in assisted reproductive technology (ART). The early-follicular long-acting GnRH-a long protocol (EFL) and the luteal phase short-acting GnRH-a long protocol (LPS) are commonly used GnRH agonist protocols. We conducted a retrospective analysis to assess and compare the rates of congenital abnormalities and safety profiles in offspring born from the EFL and LPS protocols.MethodsWe conducted a retrospective cohort study to analyze and compare neonatal data from patients who using EFL or LPS protocols at our center between January 1, 2014, and June 30, 2017. The study ultimately included 1810 neonates from 1401 cycles using the EFL protocol and 2700 neonates from 2129 cycles using the LPS protocol.The main outcome measures are gestational age at delivery, birth weight, and congenital anomaly rate.To assess the influence of various factors on congenital abnormalities, a random-effects logistic regression model was employed.ResultsThe EFL and LPS protocols led to similar congenital anomaly rates (1.64% vs. 2.35%, P = 0.149). No significant differences were found between the two groups regarding birth weight and its categories, newborn gender and congenital anomaly rate. The results of the multivariate logistic regression model indicated no association between congenital anomaly and BMI, duration of infertility, treatment protocol, fertilization method, or embryo transfer stage. Compared with singleton pregnancies, the probability of congenital defects in multiple pregnancies was 2.64 times higher (OR: 2.64, 95% CI: 1.72–4.05, P < 0.0001). Newborns with congenital defects were born with a lower gestational age compared with full-term pregnancies.ConclusionIn conclusion, the EFL protocol is considered a safe option for ensuring offspring safety, comparable with the LPS protocol; however, multiple pregnancies represent an independent risk factor for congenital abnormalities. This approach can be widely adopted; however, prioritizing single embryo transfers is strongly recommended to minimize the potential risks associated with multiple pregnancies in offspring.

Effectiveness of mass dengue vaccination with CYD-TDV (Dengvaxia®) in the state of Paraná, Brazil: integrating case-cohort and case-control designs

CYD-TDV (Dengvaxia®) was the first dengue vaccine approved, launched in Brazil in 2015 for individuals aged 9-44 years. We aimed to estimate the effectiveness of CYD-TDV in preventing symptomatic dengue cases during a campaign targeting individuals aged 15-27 years in selected municipalities in Paraná, Brazil. Additionally, we examined whether a history of dengue, as recorded by the surveillance system, modified the vaccine's effectiveness. We conducted a case-cohort analysis comparing the frequency of vaccination, with at least one dose of CYD-TDV, in individuals with dengue confirmed by RT-PCR, identified by the surveillance system during 2019 and 2020, with the vaccination coverage in the target population. Moreover, in a case-control design using weighted controls, we assessed the documented history of dengue as a modifier of the vaccine's effectiveness. We used a logistic random-effects regression model, with data clustered in municipalities and incorporating covariates such as the incidence of dengue before the campaign, age, and sex. We calculated vaccine effectiveness (VE) as (1-relative risk) x 100%. 1869 dengue cases were identified, which had a vaccination frequency significantly lower than the overall vaccination coverage in the target population (50.3% vs. 57.2%, respectively; overall VE: 21.3%; 95% confidence interval [CI]: 13.4%-28.4%). In individuals with a documented history of dengue, vaccination had a VE of 71% (95% CI: 58%-80%) in reducing the incidence of dengue. However, vaccination was not associated with a significant reduction in the overall dengue case risk in individuals without a documented history of dengue (VE: 12%; 95% CI:-21% to 36%). In this last stratum, vaccination was associated with reduced cases due to DENV-1 and DENV-4, but an excess of DENV-2 cases. Vaccination led to a significant reduction in reported dengue cases within the target population. The case-control design suggested that this reduction was primarily driven by the benefits observed in individuals with a documented history of dengue. In endemic regions with limited serological testing facilities, a previous history of dengue diagnosis recorded by epidemiological surveillance could be used to triage candidates for CYD-TDV vaccination. Research supported by Sanofi.

Unveiling ecological/evolutionary insights in HIV viral load dynamics: Allowing random slopes to observe correlational changes to CpG-contents and other molecular and clinical predictors

In the context of infectious diseases, the dynamic interplay between ever-changing host populations and viral biology demands a more flexible modeling approach than common fixed correlations. Embracing random-effects regression models allows for a nuanced understanding of the intricate ecological and evolutionary dynamics underlying complex phenomena, offering valuable insights into disease progression and transmission patterns. In this article, we employed a random-effects regression to model an observed decreasing median plasma viral load (pVL) among individuals with HIV in Mexico City during 2019–2021. We identified how these functional slope changes (i.e. random slopes by year) improved predictions of the observed pVL median changes between 2019 and 2021, leading us to hypothesize underlying ecological and evolutionary factors. Our analysis involved a dataset of pVL values from 7325 ART-naïve individuals living with HIV, accompanied by their associated clinical and viral molecular predictors. A conventional fixed-effects linear model revealed significant correlations between pVL and predictors that evolved over time. However, this fixed-effects model could not fully explain the reduction in median pVL; thus, prompting us to adopt random-effects models. After applying a random effects regression model—with random slopes and intercepts by year—, we observed potential "functional changes" within the local HIV viral population, highlighting the importance of ecological and evolutionary considerations in HIV dynamics: A notably stronger negative correlation emerged between HIV pVL and the CpG content in the pol gene, suggesting a changing immune landscape influenced by CpG-induced innate immune responses that could impact viral load dynamics. Our study underscores the significance of random effects models in capturing dynamic correlations and the crucial role of molecular characteristics like CpG content. By enriching our understanding of changing host-virus interactions and HIV progression, our findings contribute to the broader relevance of such models in infectious disease research. They shed light on the changing interplay between host and pathogen, driving us closer to more effective strategies for managing infectious diseases. Significance of the studyThis study highlights a decreasing trend in median plasma viral loads among ART-naïve individuals living with HIV in Mexico City between 2019 and 2021. It uncovers various predictors significantly correlated with pVL, shedding light on the complex interplay between host-virus interactions and disease progression. By employing a random-slopes model, the researchers move beyond traditional fixed-effects models to better capture dynamic correlations and evolutionary changes in HIV dynamics. The discovery of a stronger negative correlation between pVL and CpG content in HIV-pol sequences suggests potential changes in the immune landscape and innate immune responses, opening avenues for further research into adaptive changes and responses to environmental shifts in the context of HIV infection. The study's emphasis on molecular characteristics as predictors of pVL adds valuable insights to epidemiological and evolutionary studies of viruses, providing new avenues for understanding and managing HIV infection at the population level.

A surge in food insecurity during the COVID-19 pandemic in a cohort in Mexico City.

The COVID-19 pandemic has not only caused tremendous loss of life and health but has also greatly disrupted the world economy. The impact of this disruption has been especially harsh in urban settings of developing countries. We estimated the impact of the pandemic on the occurrence of food insecurity in a cohort of women living in Mexico City, and the socioeconomic characteristics associated with food insecurity severity. We analyzed data longitudinally from 685 women in the Mexico City-based ELEMENT cohort. Food insecurity at the household level was gathered using the Latin American and Caribbean Food Security Scale and measured in-person during 2015 to 2019 before the pandemic and by telephone during 2020-2021, in the midst of the pandemic. Fluctuations in the average of food insecurity as a function of calendar time were modeled using kernel-weighted local polynomial regression. Fixed and random-effects ordinal logistic regression models of food insecurity were fitted, with timing of data collection (pre-pandemic vs. during pandemic) as the main predictor. Food insecurity (at any level) increased from 41.6% during the pre-pandemic period to 53.8% in the pandemic stage. This increase was higher in the combined severe-moderate food insecurity levels: from 1.6% pre-pandemic to 16.8% during the pandemic. The odds of severe food insecurity were 3.4 times higher during the pandemic relative to pre-pandemic levels (p<0.01). Socioeconomic status quintile (Q) was significantly related to food insecurity (Q2 OR = 0.35 p<0.1, Q3 OR = 0.48 p = 0.014, Q4 OR = 0.24 p<0.01, and Q5 OR = 0.17 p<0.01), as well as lack of access to social security (OR = 1.69, p = 0.01), and schooling (OR = 0.37, p<0.01). Food insecurity increased in Mexico City households in the ELEMENT cohort as a result of the COVID-19 pandemic. These results contribute to the body of evidence suggesting that governments should implement well-designed, focalized programs in the context of economic crisis such as the one caused by COVID-19 to prevent families from the expected adverse health and well-being consequences associated to food insecurity, especially for the most vulnerable.