Objective College students showed a high prevalence of stress, anxiety, and depression, with medical and nursing students experiencing particularly elevated levels of mental health challenges. ...Optimism significantly influences overall well-being by promoting a healthy lifestyle and cognitive responses. However, the association of optimism with sleep quality, stress, and mental health in college students remains unexplored. This study aimed to (1) explore the associations of optimism with sleep quality, stress, and mental health and (2) ascertain whether sleep quality and stress mediate the association between optimism and mental health among college students. Methods A cross-sectional study was conducted using online surveys with students from health science majors at a public university in the northeast United States from September to December 2022. A total of 222 students participated in the study, providing data on sociodemographics, optimism, sleep quality, stress, anxiety, and depression. Parallel and serial mediation models were utilized to examine the potential mediating roles of sleep quality and stress in the association between optimism and mental health. Results The study found that optimism influences anxiety and depression through both direct and indirect pathways. In line with predictions, the parallel mediation analysis revealed that the impact of optimism on anxiety (β total = −0.598, 95% confident interval CI: −0.778 to −0.392) and depression (β total = −0.724, 95% CI: −0.919 to −0.519) was mediated by stress and sleep quality. Furthermore, the serial mediation models revealed that stress and sleep quality co-mediated the relationship betweenoptimism and anxiety (indirect effect IE = −0.074, 95% CI: −0.135 to −0.029) or depression (IE = −0.084, 95% CI: −0.142 to −0.036) in a sequential manner. Conclusion Optimism was negatively correlated with poor sleep quality, stress, anxiety, and depression. Enhanced optimism was linked to high sleep quality and less stress, anxiety, and depression. These insights emphasize the potential for school-based optimism interventions to improve sleep quality, ameliorate stress-related concerns, and alleviate mental health challenges in college students.
Background: Desired longevity represents how strongly people esteem possible extensions of their own lifetime. The association between desired longevity and mortality risk has been reported in only ...one prospective study, which examined a small sample of older participants. We aimed to examine the hypothesis that desired longevity at middle-age predicted long-term survival.Methods: In the prospective cohort study, residents aged 40–64 years were asked how long they would like to live and asked to choose one from three options: longer than, as long as, or shorter than the life expectancy. We used Cox proportional hazards model to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality according to the three groups for desired longevity, treating the “longer than” group as the reference. We conducted mediation analysis to investigate the mechanism for the association between desired longevity and mortality.Results: 39,902 residents were recruited to the study. Risk of all-cause mortality was significantly higher in the “shorter than” group (HR 1.12; 95% CI, 1.04-1.21). The association was independent of sex, age, marital status, education, medical history and health status. Regarding cause of death, mortality risk of cancer (HR 1.14; 95% CI, 1.00-1.29) and suicide (HR 2.15; 95% CI, 1.37-3.38) were also higher in the “shorter than” group. The unhealthy lifestyle mediated this association with all-cause mortality by 30.4%.Conclusions: Shorter desired longevity was significantly associated with an increased risk of all-cause mortality, and mortality from cancer and suicide. Lifestyle behaviors particularly mediated this association.
Dimethylformamide (DMF) is a volatile organic compound listed as one of the four toxicants with the highest priority for human field study. However, the effect of DMF exposure on lung function and ...the underlying mechanisms remain unknown. We aimed to investigate the exposure-response relationship and possible mechanism between internal DMF exposure and lung function alteration. We studied 3701 Chinese adults from the Wuhan-Zhuhai cohort with a 3-year follow-up. The cross-sectional relationship between urinary biomarker of DMF exposure (N-Acetyl-S-(N-methylcarbamoyl)-L-cysteine, AMCC) and lung function, and the mediating role of plasma C-reactive protein (CRP) were assessed. We also convened a sub-cohort (N = 138) to assess the stability of AMCC in repeated urine samples collected for continuous 3 days and intervals of 1, 2 and 3 years. The longitudinal association between AMCC and lung function change in 3 years was further assessed. We found a dose-response relationship between AMCC and lung function reduction. Each 2-fold increase in AMCC was cross-sectionally associated with a 23.12-mL (95% CI: −36.68, −9.55) decrease in FVC and a 19.01-mL (95% CI: −31.08, −6.93) decrease in FEV1. Increased CRP significantly mediated 5.39% and 5.87% of the AMCC-associated FVC and FEV1 reductions, respectively. With 3-year follow-up, AMCC showed a fair to excellent stability (intra-class correlation coefficients were 0.88, 0.55, 0.60 and 0.50 for continuous 3 days, intervals of 1, 2 and 3 years, respectively) and was dose-dependently associated with longitudinal lung function decline. Compared with those with persistent low AMCC levels, participants with persistent high AMCC levels had a 101.09-mL/year (95% CI: −167.40, −34.77) decline in FVC and a 66.27-mL/year (95% CI: −114.14, −18.41) decline in FEV1 in the sub-cohort. Similar results were found in the full-cohort. Our findings suggest that exposure of general population to environmental DMF may impair lung function, and systematic inflammation may be an underlying mechanism.
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•Urinary biomarker of DMF exposure (AMCC) was negatively associated with lung function.•Urinary AMCC was positively associated with plasma C-reactive protein (CRP).•Plasma CRP mediated urinary AMCC-associated lung function reduction.•Urinary AMCC showed a fair to excellent reproducibility during a 3-year period.•Higher urinary AMCC level was associated with lung function decline in 3 years.
•To the best of our knowledge, this is the first study to determine the mediation effect of attendance rate on the relationship between environmental programs (EPA TfS and other IAQ programs) and ...student academic performance. We included a large number of schools in our study (all public schools) and the school BCS data is reliable and professionally collected. We also utilized the mediation analysis model to identify the mediation effect of attendance rate (which has never been determined before) on the relationship between environmental programs and student academic performance. More importantly, this mediation analysis can be utilized by school officials and policymakers when planning interventions to address both school environment and academic problems. Our findings are useful and will attract the diverse readership of Hygiene and Environmental health advance.
Little is known regarding whether environmental programs affect student academic performance. We examined if the association between EPA Tools for School (TfS) policies or other environmental programs and student test scores were mediated by student attendance.
The 2015 School Building Condition Survey (BCS) was linked with School Report data provided by the New York State Education Department (NYSED). BCS includes school building information from 2,956 public schools while School Report data provides school attendance and test scores for different subjects in NYS. We conducted causal mediation analysis to investigate direct and indirect effects of TfS or other programs, via improving attendance, on test scores for each course while controlling for school-level socio-demographics.
EPA TfS policies were significantly associated with a lower percent of “low total score” for overall math, overall science, and multiple specific subjects (all P < 0.05). Furthermore, the associations between TfS and test scores in algebra II, trigonometry, and chemistry were significantly mediated by student attendance rate (-1.376 and -0.563 respectively). Other IAQ programs were also associated with a smaller percent of low-score students in multiple subject tests (all P <0.05). We found a mediated proportion of 6 to 43% by attendance in the association between other IAQ programs and high score academic performance. Implementing TfS and other programs can reduce the proportion of students receiving overall low scores by 2.66% and 1.37%, respectively.
EPA TfS and other IAQ programs improved student test scores in multiple subjects in NYS public schools and was partially mediated by improving attendance rate.
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Mediation analysis is routinely adopted by researchers from a wide range of applied disciplines as a statistical tool to disentangle the causal pathways by which an exposure or treatment affects an ...outcome. The counterfactual framework provides a language for clearly defining path-specific effects of interest and has fostered a principled extension of mediation analysis beyond the context of linear models. This paper describes medflex, an R package that implements some recent developments in mediation analysis embedded within the counterfactual framework. The medflex package offers a set of ready-made functions for fitting natural effect models, a novel class of causal models which directly parameterize the path-specific effects of interest, thereby adding flexibility to existing software packages for mediation analysis, in particular with respect to hypothesis testing and parsimony. In this paper, we give a comprehensive overview of the functionalities of the medflex package.
Abstract
Statistical mediation analysis has become the technique of choice in consumer research to make causal inferences about the influence of a treatment on an outcome via one or more mediators. ...This tutorial aims to strengthen two weak links that impede statistical mediation analysis from reaching its full potential. The first weak link is the path from mediator to outcome, which is a correlation. Six conditions are described that this correlation needs to meet in order to make plausible causal inferences: directionality, reliability, unconfoundedness, distinctiveness, power, and mediation. Recommendations are made to increase the plausibility of causal inferences based on statistical mediation analysis. Sweetspot analysis is proposed to establish whether an observed mediator-outcome correlation falls within the region of statistically meaningful correlations. The second weak link is the communication of mediation results. Four components of informative communication of mediation analysis are described: effect decomposition, effect size, difference testing, and data sharing. Recommendations are made to improve the communication of mediation analysis. A review of 166 recently published mediation analyses in the Journal of Consumer Research, a reanalysis of two published datasets, and Monte Carlo simulations support the conclusions and recommendations.
Consensus on the impact of information-oriented use of social media on political participation is lacking. Some argue a positive relationship, in that social media promotes participation through ...awakening the user’s agency, while others focus on the selection and disenabling effects of low-quality content. Nevertheless, both arguments focus almost exclusively on the objective conditions for participation and largely ignore users’ motivations to participate. Consequently, this article proposes online political efficacy as a mechanism linking the use of social media to political participation. Specifically, we argue that (1) the effect of the information-oriented use of social media on political participation is positively mediated through the user’s online political efficacy and (2) this mediation effect is only significant in the case of online political participation. We test these arguments within the framework of causal mediation analysis proposed by Imai et al. using data collected from the 2015 Taiwan Communication Survey.
•The mechanism between tooth loss and depression remained unclear.•Oral function such as speaking, smiling, or eating is essential for communication.•Oral function deterioration mediated the ...mechanism between tooth loss and depression.
Depression is a major health problem among older adults, for which previous studies have suggested tooth loss as a risk factor. This study examined the mediating effect of oral function and orofacial appearance in the relationship between tooth loss and depression.
This three-year follow-up longitudinal study was based on a self-reported questionnaire targeting community-dwelling older adults aged ≥65 years. We used the incidence of depressive symptoms during follow-up as the outcome, the number of remaining teeth (≥20/≤19) as the exposure, and the deterioration of oral function and orofacial appearance (speaking, smiling, and eating) as mediators. We fitted the logistic regression model including confounders and calculated the natural indirect effect (NIE), natural direct effect, and the proportion mediated (PM) by the deterioration of oral functions by applying the causal mediation analysis framework.
The mean age of the 8,875 participants was 72.7 years (1SD=5.5) and 48.0% were male. Depressive symptoms developed during follow-up in 11.5% of the participants (n=1,024). The incidence for those with ≤19 and ≥20 remaining teeth was 13.1% and 9.2%, respectively. Total effect of fewer remaining teeth (≤19) on depressive symptoms was OR=1.30 (95%CI=1.12–1.51). Difficulty in speaking (NIE OR=1.03, 95%CI=1.00–1.06, PM=12.4%), problems in smiling (NIE OR=1.04, 95%CI=1.01–1.07, PM=16.9%), and difficulty in chewing (NIE OR=1.05, 95%CI=1.02–1.09, PM=21.9%) significantly mediated the relationship.
Selection bias due to dropout.
Deterioration of oral function and orofacial appearance were mediating factors of the mechanism for the relationship between tooth loss and the incidence of depressive symptoms.
There is a strong link between mental health and physical health, but little is known about the pathways from one to the other. We analyse the direct and indirect effects of past mental health on ...present physical health and past physical health on present mental health using lifestyle choices and social capital in a mediation framework. We use data on 10,693 individuals aged 50 years and over from six waves (2002–2012) of the English Longitudinal Study of Ageing. Mental health is measured by the Centre for Epidemiological Studies Depression Scale (CES) and physical health by the Activities of Daily Living (ADL). We find significant direct and indirect effects for both forms of health, with indirect effects explaining 10% of the effect of past mental health on physical health and 8% of the effect of past physical health on mental health. Physical activity is the largest contributor to the indirect effects. There are stronger indirect effects for males in mental health (9.9%) and for older age groups in mental health (13.6%) and in physical health (12.6%). Health policies aiming at changing physical and mental health need to consider not only the direct cross-effects but also the indirect cross-effects between mental health and physical health.
•Develops a mediation framework of cross-effects of mental and physical health.•Estimates the relationship with lifestyle choices and social interaction.•Finds strong indirect cross-effects in both mental and physical health.•Physical activity is most important. Effects are strongest for male and upper age.•Policies need to consider indirect cross-effects of mental with physical health.
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