Educational Attainment and Ischemic Stroke: A Mendelian Randomization Study

Socioeconomic inequalities in cardiovascular disease: a causal perspective

Socioeconomic inequalities in cardiovascular disease (CVD) persist in high-income countries despite marked overall declines in CVD-related morbidity and mortality. After decades of research, the field has struggled to unequivocally answer a crucial question: is the association between low socioeconomic position (SEP) and the development of CVD causal? We review relevant evidence from various study designs and disciplinary perspectives. Traditional observational, family-based and Mendelian randomization studies support the widely accepted view that low SEP causally influences CVD. However, results from quasi-experimental and experimental studies are both limited and equivocal. While more experimental and quasi-experimental studies are needed to aid causal understanding and inform policy, high-quality descriptive studies are also required to document inequalities, investigate their contextual dependence and consider SEP throughout the lifespan; no simple hierarchy of evidence exists for an exposure as complex as SEP. The COVID-19 pandemic illustrates the context-dependent nature of CVD inequalities, with the generation of potentially new causal pathways linking SEP and CVD. The linked goals of understanding the causal nature of SEP and CVD associations, their contextual dependence, and their remediation by policy interventions necessitate a detailed understanding of society, its change over time and the phenotypes of CVD. Interdisciplinary research is therefore key to advancing both causal understanding and policy translation.

Association Between Social Determinants of Health and Communication Difficulties in Poststroke U.S. Hispanic and Non-Hispanic White Populations

PURPOSE

The relationship among ethnicity, social determinants of health (SDOH), and disparities in poststroke outcomes is complex, and the impact on communication difficulties is unclear. This study investigated the presence and nature of communication difficulties in poststroke non-Hispanic White (PsnHw) and Hispanic U.S. populations using population-level data.

METHOD

We performed a cross-sectional analysis of 2,861 non-Hispanic White and 353 Hispanic poststroke respondents included in the 2014-2018 National Health Interview Survey. Respondents self-reported difficulties communicating in their usual language, in addition to providing information relating to demographics and lifestyle, health care access and utilization, health status, and SDOH. We used univariate statistics, generalized linear models, and an exploratory mediation analysis, to characterize the pattern of differences between these cohorts, examine associations between variables and communication difficulties, and determine the potential intermediate role of cumulative SDOH on the likelihood of reporting communication difficulties.

RESULTS

Findings indicated a more challenging life context for the poststroke Hispanic population due to SDOH disparities. Poverty and Internet use were associated with greater and lower odds of communication difficulties for PsnHw, respectively. The mediation analysis showed that ethnicity significantly affected communication difficulties, but only when mediated by SDOH. SDOH accounted for approximately two thirds of the total effect on reporting communication difficulties.

CONCLUSIONS

This study underscores the need for uniform measures of SDOH in prospective research and for interventions aimed at mitigating health disparities through addressing disparities in SDOH. Future research should focus on evaluating the effectiveness of such strategies in diverse ethnic and socioeconomic poststroke populations.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24521419.

Socioeconomic status, obesity, individual behaviors, diabetes, and risk for frozen shoulder: A Mendelian randomization study

There are few studies on risk factors for frozen shoulder, and even fewer Mendelian randomization (MR) studies on frozen shoulder. Therefore, we conducted a two-sample MR study to explore whether socioeconomic status (years of schooling, average total household income before tax), obesity (body mass index and waist circumference), individual behaviors (smoking initiation, alcohol intake frequency, coffee intake, nonoily fish intake, tea intake, beef intake, bread intake, cheese intake, oily fish intake, and fresh fruit intake), and diabetes (type 1 and type 2 diabetes) are associated with frozen shoulder. The exposure datasets and the outcome dataset were extracted from the MRC Integrative Epidemiology Unit at the University of Bristol Open genome-wide association studies project (https://gwas.mrcieu.ac.uk/). We conducted MR analyses using the inverse variance weighted (primary method), MR-Egger, and weighted median methods and conducted heterogeneity and pleiotropy analyses. Type 1 diabetes (OR: 1.103; 95% CI: 1.053-1.156; P = .0000410) was associated with an increased risk of frozen shoulder. Cheese intake (OR: 0.490; 95% CI: 0.267-0.899; P = .0213), non-oily fish intake (OR: 0.0993; 95% CI: 0.0220-0.448; P = .00267), years of schooling (OR: 0.453; 95% CI: 0.349-0.588; P = .00000000277), and average total household income before tax (OR: 0.434; 95% CI: 0.253-0.743; P = .00236) were discovered as protective factors. No horizontal pleiotropy was found in all analyzes we performed (P > .05). Our study indicated that type 1 diabetes was a risk factor for frozen shoulder while cheese intake, non-oily fish intake, years of schooling, and average total household income before tax were considered as protective factors for frozen shoulder.

The causal effect of educational attainment on stress urinary incontinence: a two-sample mendelian randomization study

BACKGROUND

Stress urinary incontinence (SUI) is characterized by involuntary urine leakage in response to increased abdominal pressure, such as coughing, laughing, or sneezing. It significantly affects women's quality of life and imposes a substantial disease burden. While pregnancy and childbirth have been previously identified as risk factors for SUI, educational attainment may also play a role. Therefore, this paper investigates the causal relationship between educational attainment and SUI using two-sample Mendelian randomization (TSMR) analysis, years of schooling (YOS), and college or university degree (CUD) as proxies.

METHODS

Summary statistics of YOS, CUD, and SUI were obtained from genome-wide association studies (GWAS), and TSMR analysis was applied to explore potential causal relationships between them. Causal effects were mainly estimated using the standard inverse variance weighting (IVW) method, and complementary and sensitivity analyses were also performed using multiple methods.

RESULTS

The results indicate that both YOS (OR = 0.994, 95% CI: 0.992-0.996; P = 7.764E-10) and CUD (OR = 0.987, 95% CI: 0.983-0.991; P = 1.217E-09) may have a negative causal effect on SUI.

CONCLUSIONS

Improving educational attainment may go some way towards reducing the risk of SUI. Therefore, it is important to increase efforts to improve the imbalance in educational development and safeguard women's health.

Social inequalities, stressful work and non-fatal cardiovascular disease: follow-up findings from the CONSTANCES Study

BACKGROUND

Studies show that a disadvantaged socioeconomic position (SEP) and psychosocial stress at work are both independently associated with an increased risk of cardiovascular disease (CVD). But it is not clear if the effect of stress at work on CVD varies by SEP.

METHODS

We used baseline and follow-up data from the French population-based cohort study CONSTANCES, including 48 383 employed women and men aged 30-70 years. Three SEP indicators (education, income, occupation), stressful psychosocial work as measured by effort-reward imbalance, pre-existing CVD and confounders were assessed at baseline, and incident non-fatal CVD events reported during annual follow-up (up to five follow-ups) were used as outcomes. The effect modification hypothesis was both investigated on an additive and multiplicative scale.

RESULTS

SEP was inversely associated with CVD risk (eg, for low vs high income, OR 1.28 (95% CI 1.12 to 1.46)), and for all three components of stressful work CVD risks were significantly increased (eg, for effort-reward ratio OR 1.26 (95% CI 1.17 to 1.36)). Employees with a disadvantaged SEP showed moderately increased effect sizes of stressful work on CVD. However, no clear evidence of an effect modification was found.

CONCLUSIONS

Disadvantaged SEP and stressful work contribute to higher CVD risk in this cohort. Despite moderately increased effect sizes for disadvantaged SEP groups, no evidence was found to support an effect modification hypothesis.

Causal Associations between Functional/Structural Connectivity and Stroke: A Bidirectional Mendelian Randomization Study

Disruption of brain resting-state networks (RSNs) is known to be related to stroke exposure, but determining causality can be difficult in epidemiological studies. We used data on genetic variants associated with the levels of functional (FC) and structural connectivity (SC) within 7 RSNs identified from a genome-wide association study (GWAS) meta-analysis among 24,336 European ancestries. The data for stroke and its subtypes were obtained from the MEGASTROKE consortium, including up to 520,000 participants. We conducted a two-sample bidirectional Mendelian randomization (MR) study to investigate the causality relationship between FC and SC within 7 RSNs and stroke and its subtypes. The results showed that lower global mean FC and limbic network FC were associated with a higher risk of any ischemic stroke and small vessel stroke separately. Moreover, ventral attention network FC and default mode network SC have a positive causal relationship with the risk of small vessel stroke and large artery stroke, respectively. In the inverse MR analysis, any stroke and large artery stroke were causally related to dorsal attention network FC and somatomotor FC, respectively. The present study provides genetic support that levels of FC or SC within different RSNs have contrasting causal effects on stroke and its subtypes. Moreover, there is a combination of injury and compensatory physiological processes in brain RSNs following a stroke. Further studies are necessary to validate our results and explain the physiological mechanisms.