Med4way: a Stata command to investigate mediating and interactive mechanisms using the four-way effect decomposition

Association of social health with all-cause mortality and cause-specific mortality: A population-based cohort study

BACKGROUND

Previous studies only focused on the individual social factors, without considering the overall social health patterns. The present study aimed to develop an integrated social health score (SHS) and investigate its associations with all-cause, cardiovascular disease (CVD), cancer mortality.

METHODS

A total of 330,716 participants (mean age 56.3 years; 52.4 % female) from UK Biobank was included between 2006 and 2010, and thereafter followed up to 2021. SHS was calculated by using information on social connections, social engagement and social support. Cox proportional hazards models was used to estimate the hazard ratios and 95 % confidence intervals (CIs) of the association between SHS and all-cause and cause-specific mortality and the 4-way decomposition was used to quantify the mediating effect of lifestyle factors.

RESULTS

During a median follow-up period of 12.4 years, 37,897 death cases were recorded, including 4347 CVD and 10,380 cancer cases. The SHS was inversely associated with the risks of all-cause, CVD and cancer mortality in a dose-dependent manner (P for trend <0.001). The association between SHS with all-cause mortality was mediated by lifestyle factors including diet score, smoking status and alcohol consumption.

CONCLUSION

Integrated SHS was inversely associated with risks of all-cause, CVD and cancer mortality, and the associations were partially mediated by lifestyle factors. Our study highlights the importance of maintaining high levels of social health by jointly enhancing social involvement, expanding social networks, and cultivating enduring intimate relationships across the life course.

Gestational weight gain as a mediator of the relationship between pre-pregnancy body mass index and the risk of preterm birth: A four-way decomposition analysis

OBJECTIVE

The aim of the present study was to examine and quantify whether the association between preterm birth (PTB) and pre-pregnancy body mass index (BMI) is mediated by gestational weight gain (GWG).

METHODS

This is a secondary analysis of a large randomized community non-inferiority trial using a cohort design. The data of 26 101 pregnant women in their first trimester who sought prenatal care and met eligibility criteria were included. The four-way decomposition method was applied to screen for all types of association effects of pre-pregnancy BMI on the risk of PTB. These effects include the total, direct, and various indirect effects including pure mediation via GWG, interactive effects with GWG, and mediated interaction with GWG, all adjusted for potential confounders.

RESULTS

Among the study participants, 24 461 (93.7%) had term deliveries, while 1640 (6.3%) experienced PTB. The results of the study showed that there was a positive association between pre-pregnancy BMI among those with BMI more than 25 kg/m2 and the risk of PTB and this association was negatively mediated and interacted by GWG, which differed quantitatively between those who had inadequate, adequate, or excessive GWG. The total association effect showed that the risk was lowest for those who had underweight pre-pregnancy BMI and adequate GWG (excess relative risk [RR]: 0.06, 95% CI: 0.01-0.11, P value: 0.022) and was highest for those who had obese pre-pregnancy BMI and excessive GWG (excess RR: 0.67, 95% CI: 0.35-1.00, P value <0.001).

CONCLUSION

The findings of the present prospective population-based study demonstrated that pre-pregnancy BMI >25 kg/m2 is directly and positively associated with the risk of preterm birth. The highest risk of preterm birth was observed among individuals with an obese pre-pregnancy BMI who also experienced excessive GWG.

Genetic susceptibility to chronic diseases leads to heart failure among Europeans: the influence of leukocyte telomere length

BACKGROUND

Genetic susceptibility to various chronic diseases has been shown to influence heart failure (HF) risk. However, the underlying biological pathways, particularly the role of leukocyte telomere length (LTL), are largely unknown. We investigated the impact of genetic susceptibility to chronic diseases and various traits on HF risk, and whether LTL mediates or modifies the pathways.

METHODS

We conducted prospective cohort analyses on 404 883 European participants from the UK Biobank, including 9989 incident HF cases. Multivariable Cox regression was used to estimate associations between HF risk and 24 polygenic risk scores (PRSs) for various diseases or traits previously generated using a Bayesian approach. We assessed multiplicative interactions between the PRSs and LTL previously measured in the UK Biobank using quantitative PCR. Causal mediation analyses were conducted to estimate the proportion of the total effect of PRSs acting indirectly through LTL, an integrative marker of biological aging.

RESULTS

We identified 9 PRSs associated with HF risk, including those for various cardiovascular diseases or traits, rheumatoid arthritis (P = 1.3E-04), and asthma (P = 1.8E-08). Additionally, longer LTL was strongly associated with decreased HF risk (P-trend = 1.7E-08). Notably, LTL strengthened the asthma-HF relationship significantly (P-interaction = 2.8E-03). However, LTL mediated only 1.13% (P < 0.001) of the total effect of the asthma PRS on HF risk.

CONCLUSIONS

Our findings shed light onto the shared genetic susceptibility between HF risk, asthma, rheumatoid arthritis, and other traits. Longer LTL strengthened the genetic effect of asthma in the pathway to HF. These results support consideration of LTL and PRSs in HF risk prediction.

Interrelationships between physical multimorbidity, depressive symptoms and cognitive function among older adults in China, India and Indonesia: A four-way decomposition analysis

OBJECTIVE

This paper explores the role of depressive symptoms (mediator/moderator) in the association between physical multimorbidity (exposure) and cognitive function (outcome) among older adults in the three most populous middle-income countries.

METHODS

This study used cross-sectional data from China (2015 China Health and Retirement Longitudinal Study), India (2017/2018 Longitudinal Ageing Study in India), and Indonesia (2014/2015 Indonesian Family Life Survey), with a total sample of 73,199 respondents aged ≥ 45 years. Three domains of cognitive tests were harmonised across surveys, including time orientation, word recall, and numeracy. The four-way decomposition analysis assessed the mediation and interaction effects between exposure, mediator/moderator, and outcome, adjusted for covariates.

RESULTS

The mean age of the respondents (in years) was slightly younger in Indonesia (56.0, SD = 8.8) than in China (59.5, SD = 9.3) and India (60.0, SD = 10.5). The proportion of male respondents was 49.3 % in China, 47.3 % in India, and 47.5 % in Indonesia. Respondents in China had the highest mean cognitive function z scores (54.7, SD = 19.9), followed by India (51.1, SD = 20.0) and Indonesia (51.0, SD = 18.4). Physical multimorbidity was associated with lower cognitive function in China and India (p < 0.0001), with 48.4 % and 40.0 % of the association explained by the mediating effect of depressive symptoms ('overall proportion due to mediation'). The association was not found in Indonesia.

CONCLUSION

Cognitive functions were lower among individuals with physical multimorbidity, and depressive symptoms mainly explained the association. Addressing depressive symptoms among persons with physical multimorbidity is likely to have not only an impact on their mental health but could prevent cognitive decline.

Association Between Awareness of Limiting Food Intake and All-cause Mortality: A Cohort Study in Japan

BACKGROUND

Improving diets requires an awareness of the need to limit foods for which excessive consumption is a health problem. Since there are limited reports on the link between this awareness and mortality risk, we examined the association between awareness of limiting food intake (energy, fat, and sweets) and all-cause mortality in a Japanese cohort study.

METHODS

Participants comprised 58,772 residents (27,294 men; 31,478 women) aged 35-69 years who completed baseline surveys of the Japan Multi-Institutional Collaborative Cohort Study from 2004 to 2014. Hazard ratios (HRs) for all-cause mortality and 95% confidence intervals (CIs) were estimated by sex using a Cox proportional hazard model, with adjustment for related factors. Mediation analysis with fat intake as a mediator was also conducted.

RESULTS

The mean follow-up period was 11 years, and 2,516 people died. Estimated energy and fat intakes according to the Food Frequency Questionnaire were lower in those with awareness of limiting food intake than in those without this awareness. Women with awareness of limiting fat intake showed a significant decrease in mortality risk (HR 0.73; 95% CI, 0.55-0.94). Mediation analysis revealed that this association was due to the direct effect of the awareness of limiting fat intake and that the total effect was not mediated by actual fat intake. Awareness of limiting energy or sweets intake was not related to mortality risk reduction.

CONCLUSION

Awareness of limiting food intake had a limited effect on reducing all-cause mortality risk.

Regional differences in heart failure risk in the United Kingdom are partially explained by biological aging

Background

Heart failure (HF) risk is greater in rural versus urban regions in the United States (US), potentially due to differences in healthcare coverage and access. Whether this excess risk applies to countries with universal healthcare is unclear and the underlying biological mechanisms are unknown. In the prospective United Kingdom (UK) Biobank, we investigated urban-rural regional differences in HF risk and the mechanistic role of biological aging.

Methods

Multivariable Cox regression was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of incident HF in relation to residential urban-rural region and a Biological Health Score (BHS) that reflects biological aging from environmental, social, or dietary stressors. We estimated the proportion of the total effect of urban-rural region on HF mediated through BHS.

Results

Among 417,441 European participants, 10,332 incident HF cases were diagnosed during the follow-up. Compared to participants in large urban regions of Scotland, those in England/Wales had significantly increased HF risk (smaller urban: HR = 1.83, 95%CI: 1.64-2.03; suburban: HR = 1.77, 95%CI: 1.56-2.01; very rural: HR = 1.61, 95%CI: 1.39-1.85). Additionally, we found a dose-response relationship between increased biological aging and HF risk (HRper 1 SD increase = 1.14 (95%CI: 1.12-1.17). Increased biological aging mediated a notable 6.6% (p < 0.001) of the total effect of urban-rural region on HF.

Conclusion

Despite universal healthcare in the UK, disparities in HF risk by region were observed and may be partly explained by environmental, social, or dietary factors related to biological aging. Our study contributes to precision public health by informing potential biological targets for intervention.

Multi-Trait Body Shape Phenotypes and Breast Cancer Risk in Postmenopausal Women: A Causal Mediation Analysis in the UK Biobank Cohort

Body shape phenotypes combining multiple anthropometric traits have been linked to postmenopausal breast cancer (BC). However, underlying biological pathways remain poorly understood. This study investigated to what extent the associations of body shapes with postmenopausal BC risk is mediated by biochemical markers. The study included 176,686 postmenopausal women from UK Biobank. Four body shape phenotypes were derived from principal component (PC) analysis of height, weight, body mass index, waist and hip circumferences, and waist-to-hip ratio (WHR). The four-way decomposition of the total effect was used to estimate mediation and interaction effects simultaneously as well as the mediated proportions. After 10.9 years median follow-up, 6,396 incident postmenopausal BC were diagnosed. There was strong evidence of positive associations between PC1 (general obesity) and PC2 (tall, low WHR), and BC risk. The association of PC1 with BC risk was positively mediated by testosterone and negatively by insulin-like growth factor-1 (IGF-1), with the overall proportion mediated (sum of the mediated interaction and pure indirect effect (PIE)) accounting for 11.4% (95% confidence intervals: 5.1 to 17.8%) and -12.2% (-20.5% to -4.0%) of the total effect, respectively. Small proportions of the association between PC2 and BC were mediated by IGF-1 (PIE: 2.8% (0.6 to 4.9%)), and sex hormone-binding globulin (SHBG) (PIE: -6.1% (-10.9% to -1.3%)). Our findings are consistent with differential pathways linking different body shapes with BC risk, with a suggestive mediation through testosterone and IGF-1 in the relationship of a generally obese body shape and BC risk, while IGF-1 and SHBG may mediate a tall/lean body shape-BC risk association.

Mediating and moderating effects of plasma proteomic biomarkers on the association between poor oral health problems and incident dementia: The UK Biobank study

The plasma proteome can mediate poor oral health problems (POHP)'s link to incident dementia. We screened 37,269 UK Biobank participants 50-74 years old (2006-2010) for prevalent POHP, further tested against 1463 plasma proteins and incident dementia over up to 15 years of follow-up. Total effect (TE) of POHP-dementia through plasma proteomic markers was decomposed into pure indirect effect (PIE), interaction referent (INTREF), controlled direct effect (CDE), or mediated interaction (INTMED). POHP increased the risk of all-cause dementia by 17% (P < 0.05). Growth differentiation factor 15 (GDF15) exhibited the strongest mediating effects (PIE > 0, P < 0.001), explaining 28% the total effect of POHP on dementia, as a pure indirect effect. A first principal component encompassing top 4 mediators (GDF15, IL19, MMP12, and ACVRL1), explained 11% of the POHP-dementia effect as a pure indirect effect. Pathway analysis including all mediators (k = 173 plasma proteins) revealed the involvement of the immune system, signal transduction, metabolism, disease, and gene expression, while STRING analysis indicated that top mediators within the first principal component were also represented in the two largest proteomic clusters. The dominant biological GO pathway for the GDF15 cluster was GO:0007169 labeled as "transmembrane receptor protein tyrosine kinase signaling pathway." Dementia is linked to POHP mediated by GDF15 among several proteomic markers.

Relationships of depression and antidepressant use with epigenetic age acceleration and all-cause mortality among postmenopausal women

We investigated relations of depressive symptoms, antidepressant use, and epigenetic age acceleration with all-cause mortality risk among postmenopausal women. Data were analyzed from ≤1,900 participants in the Women's Health Initiative study testing four-way decomposition models. After a median 20.4y follow-up, 1,161 deaths occurred. Approximately 11% had elevated depressive symptoms (EDS+), 7% were taking antidepressant medication at baseline (ANTIDEP+), while 16.5% fell into either category (EDS_ANTIDEP+). Baseline ANTIDEP+, longitudinal transition into ANTIDEP+ and accelerated epigenetic aging directly predicted increased mortality risk. GrimAge DNA methylation age acceleration (AgeAccelGrim) partially mediated total effects of baseline ANTIDEP+ and EDS_ANTIDEP+ on all-cause mortality risk in socio-demographic factors-adjusted models (Pure Indirect Effect >0, P < 0.05; Total Effect >0, P < 0.05). Thus, higher AgeAccelGrim partially explained the relationship between antidepressant use and increased all-cause mortality risk, though only prior to controlling for lifestyle and health-related factors. Antidepressant use and epigenetic age acceleration independently predicted increased all-cause mortality risk. Further studies are needed in varying populations.

Serum neurofilament light chain as a prognostic marker of all-cause mortality in a national sample of US adults

Neurofilament light chain (NfL) is a neuron-specific structural protein released into the extracellular space, including body fluids, upon neuroaxonal damage. Despite evidence of a link in neurological disorders, few studies have examined the association of serum NfL with mortality in population-based studies. Data from the National Health and Nutrition Survey were utilized including 2,071 Non-Hispanic White, Non-Hispanic Black and Hispanic adult participants and adult participants of other ethnic groups (20-85 years) with serum NfL measurements who were followed for ≤ 6 years till 2019. We tested the association of serum NfL with mortality in the overall population and stratified by sex with the addition of potential interactive and mediating effects of cardio-metabolic risk factors and nutritional biomarkers. Elevated serum NfL levels (above median group) were associated with mortality risk compared to the below median NfL group in the overall sample (P = 0.010), with trends observed within each sex group (P < 0.10). When examining Loge NfL as a continuum, one standard deviation of Loge NfL was associated with an increased mortality risk (HR = 1.88, 95% CI 1.60-2.20, P < 0.001) in the reduced model adjusted for age, sex, race, and poverty income ratio; a finding only slightly attenuated with the adjustment of lifestyle and health-related factors. Four-way decomposition indicated that there was, among others, mediated interaction between NfL and HbA1c and a pure inconsistent mediation with 25(OH)D3 in predicting all-cause mortality, in models adjusted for all other covariates. Furthermore, urinary albumin-to-creatinine ratio interacted synergistically with NfL in relation to mortality risk both on the additive and multiplicative scales. These data indicate that elevated serum NfL levels were associated with all-cause mortality in a nationally representative sample of US adults.

The association of body mass index variability with cardiovascular disease and mortality: a mediation analysis of pooled cohorts

Aim

We aimed to investigate the effect of BMI variability on CVD and mortality and to explore the mediation effects of the main cardiovascular risk factors contributing to this association.

Method

Participants aged 40-65 years were pooled from three cohort studies(ARIC [Atherosclerosis Risk in Communities], MESA [Multi-ethnic Study of Atherosclerosis], and TLGS [Tehran Lipid and Glucose Study]. We employed root mean squared error of the fractional mixed model to calculate BMI variability in the measurement period. In the event assessment period, the hazard ratios for CVD and mortality were estimated using Cox proportional hazard regression models. In the next step, the mediation and interaction effects of fasting plasma glucose, total cholesterol, and systolic blood pressure were determined.

Results

A total of 19073 participants were included in this pooled analysis. During a median of 20.7 years of follow-up, 3900 (20.44%) CVD and 6480 (33.97%) all-cause mortality events were recorded. After adjusting for potential confounders, BMI variability was linked to the 1.3 (1.2-1.4) and 1.7 (1.6-1.8) increased risk of CVD and mortality, respectively. Fasting plasma glucose mediated approximately 24% and 8% of the effect of BMI variability on CVD and mortality, respectively. However, systolic blood pressure and total cholesterol did not have mediation effects in this association.

Conclusion

High BMI variability is independently associated with the development of CVD and mortality. This association is partly mediated through fasting plasma glucose. Modern cardiometabolic therapies that lower fasting glucose may reduce the risk of future CVD and mortality in individuals with high BMI variability.

Social health and subsequent cognitive functioning in people aged 50 years and older: examining the mediating roles of depressive symptoms and inflammatory biomarkers in two European longitudinal studies

BACKGROUND

Social health markers, including marital status, contact frequency, network size, and social support, have been shown to be associated with cognition. However, the mechanisms underlying these associations remain poorly understood. We investigated whether depressive symptoms and inflammation mediated associations between social health and subsequent cognition.

METHODS

In the English Longitudinal Study of Ageing (ELSA), a nationally representative longitudinal study in England, UK, we sampled 7136 individuals aged 50 years or older living in private households without dementia at baseline or at the intermediate mediator assessment timepoint, who had recorded information on at least one social health marker and potential mediator. We used four-way decomposition to examine to what extent depressive symptoms, C-reactive protein, and fibrinogen mediated associations between social health and subsequent standardised cognition (verbal fluency and delayed and immediate recall), including cognitive change, with slopes derived from multilevel models (12-year slope). We examined whether findings were replicated in the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K), a population-based longitudinal study in Sweden, in a sample of 2604 individuals aged 60 years or older living at home or in institutions in Kungsholmen (central Stockholm) without dementia at baseline or at the intermediate mediator assessment timepoint (6-year slope). Social health exposures were assessed at baseline, potential mediators were assessed at an intermediate timepoint (wave 2 in ELSA and 6-year follow-up in SNAC-K); cognitive outcomes were assessed at a single timepoint (wave 3 in ELSA and 12-year follow-up in SNAC-K), and cognitive change (between waves 3 and 9 in ELSA and between 6-year and 12-year follow-ups in SNAC-K).

FINDINGS

The study sample included 7136 participants from ELSA, of whom 3962 (55·5%) were women and 6934 (97·2%) were White; the mean baseline age was 63·8 years (SD 9·4). Replication analyses included 2604 participants from SNAC-K, of whom 1604 (61·6%) were women (SNAC-K did not collect ethnicity data); the mean baseline age was 72·3 years (SD 10·1). In ELSA, we found indirect effects via depressive symptoms of network size, positive support, and less negative support on subsequent verbal fluency, and of positive support on subsequent immediate recall (pure indirect effect [PIE] 0·002 [95% CI 0·001-0·003]). Depressive symptoms also partially mediated associations between less negative support and slower decline in immediate recall (PIE 0·001 [0·000-0·002]) and in delayed recall (PIE 0·001 [0·000-0·002]), and between positive support and slower decline in immediate recall (PIE 0·001 [0·000-0·001]). We did not observe mediation by inflammatory biomarkers. Findings of mediation by depressive symptoms in the association between positive support and verbal fluency and between positive support and change in immediate recall were replicated in SNAC-K.

INTERPRETATION

The findings of this study provide new insights into mechanisms linking social health with cognition, suggesting that associations between interactional aspects of social health, especially social support, and cognition are partly underpinned by depressive symptoms.

FUNDING

EU Joint Programme-Neurodegenerative Disease Research (JPND) and Alzheimer's Society.

TRANSLATION

For the Swedish translation of the abstract see Supplementary Materials section.

C3 Hypocomplementemia Predicts the Progression of CKD towards End-Stage Kidney Disease in IgA Nephropathy, Irrespective of Histological Evidence of Thrombotic Microangiopathy

Background: IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. IgAN causes end-stage kidney disease (ESKD) in 30-40% of all cases. The activation of the complement system by pathological circulating IgAs, which is often associated with low serum C3 levels (LowC3), seems to play a crucial role. Previous studies have shown an association between histological evidence of TMA, which is the result of alternative complement activation, and poor outcomes. However, it is not known to what extent the decrease in serum C3 levels reflects ongoing TMA injury. Our study aimed at assessing the association between LowC3 and ESKD and whether this association reflects ongoing TMA. Methods: We enrolled all patients with biopsy-proven IgAN and followed-up patients until their last visit, ESKD, or death. Results: Of the 56 patients included in the study, 12 (21%) presented low serum C3 (LowC3) at the time of renal biopsy. TMA was significantly more frequent in the LowC3 group [7/12 (58%) vs. 9/44 (20%), p = 0.02]. After adjusting for potential confounders, LowC3 was strongly associated with an increased hazard of ESKD (hazard ratio [HR]: 5.84 [95%CI: 1.69, 20.15; p = 0.005). The association was not affected by adjusting for TMA. The estimated overall proportion of the relation between C3 and ESKD mediated by TMA was low and not statistically significant. Conclusions: Our study provides evidence that C3 hypocomplementemia is associated with an increased risk of ESKD through mechanisms that are largely independent from TMA.

Incidence of coronary heart disease among remote workers: a nationwide web-based cohort study

Coronary heart disease (CHD) risk is influenced by socioeconomic status-related parameters, particularly occupation. We investigated occupational gaps in CHD risk and how the introduction of remote work moderated the observed occupational differences in CHD risk during the coronavirus disease 2019 pandemic in Japan. Data from a web-based, nationwide cohort study, comprising 17,640 workers (aged 20-65 years) with baseline data from December 2020, were analyzed. Participants were grouped by occupation as upper-level nonmanual workers (managers/professionals) and others (reference group). The primary outcome was CHD (angina pectoris/myocardial infarction) onset retrospectively confirmed at the 1-year follow-up survey. Upper-level nonmanual workers exhibited a higher CHD incidence than others (2.3% vs. 1.7%). This association was pronounced in the younger (20-49 years) population, with a significant CHD risk (adjusted risk ratio = 1.88). Upper-level nonmanual workers exhibited nearly 15% higher remote work prevalence, with a significant remote work-related CHD risk (adjusted risk ratio = 1.92). The mediating effects of remote work explained an overall disparity of 32% among the younger population. Occupational gaps in CHD incidence in Japan differ from those in Western countries, where upper-level nonmanual workers have lower cardiovascular risk. In Japan, remote work can mediate CHD risk in the younger population of upper-level nonmanual workers.

Self-reported periodontitis association with impaired smell and taste: A multicenter survey

OBJECTIVES

To investigate the association between self-reported periodontitis and the senses of taste and smell among employees of one Danish and two American universities.

MATERIALS AND METHODS

Data were collected through a digital survey. A total of 1239 individuals from Aarhus University - Denmark, the University of Iowa, and the University of Florida - USA were included. Self-reported periodontitis was the exposure. The perceived senses of taste and smell were the outcomes and were measured through a visual analog scale (VAS). Self-perceived halitosis was the mediator. Confounders were age, sex, income, education, xerostomia, COVID-19, smoking, body mass index, and diabetes. The total effect was decomposed into direct and indirect using a counterfactual approach.

RESULTS

The total effect of periodontitis on an impaired sense of taste was OR 1.56 (95% CI [1.02, 2.09]), of which 23% was mediated by halitosis (OR 1.13; 95% CI [1.03, 1.22]). Additionally, individuals with self-reported periodontitis had a 53% higher chance of having impaired smell (OR 1.53; 95% CI [1.00, 2.04]), with halitosis mediating 21% of the total effect (OR 1.11; 95% CI [1.02, 1.20]).

CONCLUSION

Our findings suggest that periodontitis is associated with distorted senses of taste and smell. Additionally, this association appears to be mediated by halitosis.

Obesity is associated with biliary tract cancer mortality and incidence: A pooled analysis of 21 cohort studies in the Asia Cohort Consortium

Body fatness is considered a probable risk factor for biliary tract cancer (BTC), whereas cholelithiasis is an established factor. Nevertheless, although obesity is an established risk factor for cholelithiasis, previous studies of the association of body mass index (BMI) and BTC did not take the effect of cholelithiasis fully into account. To better understand the effect of BMI on BTC, we conducted a pooled analysis using population-based cohort studies in Asians. In total, 905 530 subjects from 21 cohort studies participating in the Asia Cohort Consortium were included. BMI was categorized into four groups: underweight (<18.5 kg/m2 ); normal (18.5-22.9 kg/m2 ); overweight (23-24.9 kg/m2 ); and obese (25+ kg/m2 ). The association between BMI and BTC incidence and mortality was assessed using hazard ratios (HR) and 95% confidence intervals (CIs) by Cox regression models with shared frailty. Mediation analysis was used to decompose the association into a direct and an indirect (mediated) effect. Compared to normal BMI, high BMI was associated with BTC mortality (HR 1.19 [CI 1.02-1.38] for males, HR 1.30 [1.14-1.49] for females). Cholelithiasis had significant interaction with BMI on BTC risk. BMI was associated with BTC risk directly and through cholelithiasis in females, whereas the association was unclear in males. When cholelithiasis was present, BMI was not associated with BTC death in either males or females. BMI was associated with BTC death among females without cholelithiasis. This study suggests BMI is associated with BTC mortality in Asians. Cholelithiasis appears to contribute to the association; and moreover, obesity appears to increase BTC risk without cholelithiasis.

The role of differential exposure and susceptibility to heavy drinking linking income inequalities and tooth loss: An investigation of the alcohol harm paradox using a four-way decomposition analysis

OBJECTIVES

To examine the extent to which the effect of income inequalities on tooth loss is attributable to differential exposure and susceptibility to heavy drinking in older Brazilian adults.

METHODS

We conducted a secondary analysis using data from The Brazilian Longitudinal Study of Ageing (ELSI-Brazil 2015-2016), a nationally representative sample of community-dwelling people aged 50 years and over. Causal mediation analysis based on the counterfactual outcome framework decomposed the effect of income on tooth loss mediated by heavy drinking into four components (four-way decomposition): controlled direct effect (neither mediation nor interaction), reference interaction (interaction only), mediated interaction (both mediation and interaction) and pure indirect effect (mediation only). Proportions of effect attributable to each component were calculated to estimate the differential exposure (the sum of the third and fourth components) and differential susceptibility (the sum of the second and third components) to heavy drinking.

RESULTS

The analytical sample comprised 8114 participants. After adjusting for covariates, 7.3% (95% CI: 3.8%; 10.9%) and -39.5% (95% CI: -75.8%; -3.3%) of the effects of income on tooth loss were attributable to differential exposure and susceptibility to heavy drinking, respectively, consistent with the alcohol harm paradox. When setting non-functional dentition as outcome, only the effect of differential susceptibility remained (-81.7% [95% CI: -128.2%; -35.2%]).

CONCLUSION

Our findings suggest that individuals of low-income groups appear to be more susceptible to the effects of heavy drinking on tooth loss.

Ambient particulate matter and surrounding greenness in relation to sleep quality among pregnant women: A nationwide cohort study

Background

Particulate air pollution and residential greenness are associated with sleep quality in the general population; however, their influence on maternal sleep quality during pregnancy has not been assessed.

Objective

This cross-sectional study investigated the individual and interactive effects of exposure to particulate matter (PM) air pollution and residential greenness on sleep quality in pregnant women.

Methods

Pregnant women (n = 4933) enrolled in the Korean Children's Environmental Health Study with sleep quality information and residential address were included. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). The average concentrations of PM (PM2.5 and PM10) during pregnancy were estimated through land use regression, and residential greenness in a 1000 m buffer area around participants' residences was estimated using the Normalized Difference Vegetation Index (NDVI1000-m). Modified Poisson regression models were used to estimate the associations between PM and NDVI and poor sleep quality (PSQI >5) after controlling for a range of covariates. A four-way mediation analysis was conducted to examine the mediating effects of PM.

Results

After adjusting for confounders, each 10 μg/m3 increase in PM2.5 and PM10 exposure was associated with a higher risk of poor sleep quality (relative risk [RR]: 1.06; 95% confidence interval [CI]: 1.01, 1.11; and RR: 1.09; 95% CI: 1.06, 1.13, respectively), and each 0.1-unit increase in NDVI1000-m was associated with a lower risk of poor sleep quality (RR: 0.97; 95% CI: 0.95, 0.99). Mediation analysis showed that PM mediated approximately 37%-56% of the association between residential greenness and poor sleep quality.

Conclusions

This study identified a positive association between residential greenness and sleep quality. Furthermore, these associations are mediated by a reduction in exposure to particulate air pollution and highlight the link between green areas, air pollution control, and human health.

The role of depression and use of alcohol and other drugs after partner suicide in the association between suicide bereavement and suicide: cohort study in the Danish population

BACKGROUND

Although suicide bereavement is associated with suicide and self-harm, evidence regarding mechanisms is lacking. We investigated whether depression and substance use (alcohol and/or other drugs) explain the association between partner suicide bereavement and suicide.

METHODS

Linkage of nationwide, longitudinal data from Denmark for the period 1980-2016 facilitated a comparison of 22 668 individuals exposed to bereavement by a partner's suicide with 913 402 individuals bereaved by a partner's death due to other causes. Using causal mediation models, we estimated the degree to which depression and substance use (considered separately) mediated the association between suicide bereavement and suicide.

RESULTS

Suicide-bereaved partners were found to have a higher risk of suicide (HRadj = 1.59, 95% CI 1.36-1.86) and of depression (ORadj 1.16, 95% CI 1.09-1.25) when compared to other-bereaved partners, but a lower risk of substance use (ORadj 0.83; 95% CI 0.78-0.88). An increased risk of suicide was found among any bereaved individuals with a depression diagnosis recorded post-bereavement (ORadj 3.92, 95% CI 3.55-4.34). Mediation analysis revealed that depression mediated 2% (1.68%; 95% CI 0.23%-3.14%; p = 0.024) of the association between suicide bereavement and suicide in partners when using bereaved controls.

CONCLUSIONS

Depression is a partial mediator of the association between suicide bereavement and suicide. Efforts to prevent and optimize the treatment of depression in suicide-bereaved people could reduce their suicide risk. Our findings might be conservative because we did not include cases of depression diagnosed in primary care. Further work is needed to understand this and other mediators.

Early Initiation of Antiretroviral Therapy is Protective Against Seizures in Children With HIV in Zambia: A Prospective Case-Control Study

BACKGROUND

Seizures are relatively common among children with HIV in low- and middle-income countries and are associated with significant morbidity and mortality. Early treatment with antiretroviral therapy (ART) may reduce this risk by decreasing rates of central nervous system infections and HIV encephalopathy.

METHODS

We conducted a prospective, unmatched case-control study. We enrolled children with new-onset seizure from University Teaching Hospital in Lusaka, Zambia and 2 regional hospitals in rural Zambia. Controls were children with HIV and no history of seizures. Recruitment took place from 2016 to 2019. Early treatment was defined as initiation of ART before 12 months of age, at a CD4 percentage >15% in children aged 12-60 months or a CD4 count >350 cells/mm 3 for children aged 60 months or older. Logistic regression models were used to evaluate the association between potential risk factors and seizures.

RESULTS

We identified 73 children with new-onset seizure and compared them with 254 control children with HIV but no seizures. Early treatment with ART was associated with a significant reduction in the odds of seizures [odds ratio (OR) 0.04, 95% confidence interval: 0.02 to 0.09; P < 0.001]. Having an undetectable viral load at the time of enrollment was strongly protective against seizures (OR 0.03, P < 0.001), whereas history of World Health Organization Stage 4 disease (OR 2.2, P = 0.05) or CD4 count <200 cells/mm 3 (OR 3.6, P < 0.001) increased risk of seizures.

CONCLUSIONS

Early initiation of ART and successful viral suppression would likely reduce much of the excess seizure burden in children with HIV.

Air pollution, lung function and mortality: survival and mediation analyses in UK Biobank

Background

Air pollution is associated with lower lung function, and both are associated with premature mortality and cardiovascular disease (CVD). Evidence remains scarce on the potential mediating effect of impaired lung function on the association between air pollution and mortality or CVD.

Methods

We used data from UK Biobank (n∼200 000 individuals) with 8-year follow-up to mortality and incident CVD. Exposures to particulate matter <10 µm (PM10), particulate matter <2.5 µm (PM2.5) and nitrogen dioxide (NO2) were assessed by land-use regression modelling. Lung function (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and the FEV1/FVC ratio) was measured between 2006 and 2010 and transformed to Global Lung Function Initiative (GLI) z-scores. Adjusted Cox proportional hazards and causal proportional hazards mediation analysis models were fitted, stratified by smoking status.

Results

Lower FEV1 and FVC were associated with all-cause and CVD mortality, and incident CVD, with larger estimates in ever- than never-smokers (all-cause mortality hazard ratio per FEV1 GLI z-score decrease 1.29 (95% CI 1.24-1.34) for ever-smokers and 1.16 (95% CI 1.12-1.21) for never-smokers). Long-term exposure to PM2.5 or NO2 was associated with incident CVD, with similar effect sizes for ever- and never-smokers. Mediated proportions of the air pollution-all-cause mortality estimates driven by FEV1 were 18% (95% CI 2-33%) for PM2.5 and 27% (95% CI 3-51%) for NO2. Corresponding mediated proportions for incident CVD were 9% (95% CI 4-13%) for PM2.5 and 16% (95% CI 6-25%) for NO2.

Conclusions

Lung function may mediate a modest proportion of associations between air pollution and mortality and CVD outcomes. Results likely reflect the extent of either shared mechanisms or direct effects relating to lower lung function caused by air pollution.

Effect of an enhanced public health contact tracing intervention on the secondary transmission of SARS-CoV-2 in educational settings: The four-way decomposition analysis

Background

The aim of our study was to test the hypothesis that the community contact tracing strategy of testing contacts in households immediately instead of at the end of quarantine had an impact on the transmission of SARS-CoV-2 in schools in Reggio Emilia Province.

Methods

We analysed surveillance data on notification of COVID-19 cases in schools between 1 September 2020 and 4 April 2021. We have applied a mediation analysis that allows for interaction between the intervention (before/after period) and the mediator.

Results

Median tracing delay decreased from 7 to 3.1 days and the percentage of the known infection source increased from 34-54.8% (incident rate ratio-IRR 1.61 1.40-1.86). Implementation of prompt contact tracing was associated with a 10% decrease in the number of secondary cases (excess relative risk -0.1 95% CI -0.35-0.15). Knowing the source of infection of the index case led to a decrease in secondary transmission (IRR 0.75 95% CI 0.63-0.91) while the decrease in tracing delay was associated with decreased risk of secondary cases (1/IRR 0.97 95% CI 0.94-1.01 per one day of delay). The direct effect of the intervention accounted for the 29% decrease in the number of secondary cases (excess relative risk -0.29 95%-0.61 to 0.03).

Conclusions

Prompt contact testing in the community reduces the time of contact tracing and increases the ability to identify the source of infection in school outbreaks. Although there are strong reasons for thinking it is a causal link, observed differences can be also due to differences in the force of infection and to other control measures put in place.

Funding

This project was carried out with the technical and financial support of the Italian Ministry of Health - CCM 2020 and Ricerca Corrente Annual Program 2023.

Relationship between abdominal circumference and the incidence of hyperuricemia in the general Japanese population

In this study, we aimed to separately evaluate the relationship between waist circumference and the incidence of hyperuricemia in men and women in the general Japanese population. We performed a population-based longitudinal study using data from the annual health examination of residents of Iki City, Japan. A total of 5567 participants without hyperuricemia at baseline were included in the analysis. The men and women were placed into groups according to the tertile of waist circumference. The outcome was incident hyperuricemia (uric acid > 416 µmol/L [7.0 mg/dL]). The relationship between waist circumference and the incidence of hyperuricemia was investigated using Cox proportional hazards models. During the follow-up period, hyperuricemia developed in 697 people (551 men and 146 women). The incidence (per 1000 person-years) of hyperuricemia increased with increasing waist circumference in the men (34.9 for tertile 1, 49.9 for tertile 2 and 63.3 for tertile 3; Ptrend < 0.001) and women (5.5 for tertile 1, 6.3 for tertile 2 and 11.9 for tertile 3; Ptrend < 0.001). Significant associations were identified after adjustment for potential confounders (men: Ptrend < 0.001; women: Ptrend = 0.014). In conclusion, both men and women with larger waist circumferences were at higher risks of subsequent hyperuricemia.

Healthy lifestyles, systemic inflammation and breast cancer risk: a mediation analysis

BACKGROUND

Despite the known association between healthy lifestyles and reduced risk of breast cancer, it remains unclear whether systemic inflammation, as a consequence of unhealthy lifestyles, may mediate the association.

METHODS

A cohort study of 259,435 female participants in the UK Biobank was conducted to estimate hazard ratio (HR) for breast cancer according to 9 inflammation markers using Cox regression models. We further estimated the percentage of total association between healthy lifestyle index (HLI) and breast cancer that is mediated by these inflammation markers.

RESULTS

During 2,738,705 person-years of follow-up, 8,889 cases of breast cancer were diagnosed among 259,435 women in the UK Biobank cohort. Higher level of C-reactive protein (CRP), systemic immune-inflammation index (SII), CRP-to-albumin Ratio (CAR), CRP-to-lymphocyte Ratio (CLR), monocyte-to-HDL-c ratio (MHR), and neutrophil-to-HDL-c ratio (NHR) were associated with increased breast cancer risk, while a higher lymphocyte-to-monocyte ratio (LMR) was associated with a lower risk. The inverse association between HLI and breast cancer was weakly mediated by CRP (8.5%), SII (1.71%), CAR (8.66%), CLR (6.91%), MHR (6.27%), and NHR (7.33%). When considering individual lifestyle factors, CRP and CAR each mediated 16.58% and 17.20%, respectively, of the associations between diet score and breast cancer risk, while the proportion mediated for physical activity and breast cancer were 12.13% and 11.48%, respectively. Furthermore, MHR was found to mediate 13.84% and 12.01% of the associations between BMI, waist circumference, and breast cancer.

CONCLUSION

The association of HLI and breast cancer is weakly mediated by the level of inflammation, particularly by CRP and CAR. Systemic inflammatory status may be an intermediate in the biological pathway of breast cancer development.

Tooth loss mediates the association between smoking and an increased risk of dementia among older adults: The JAGES prospective cohort study

AIM

Tooth loss has various causes; however, its cause-specific effects on health outcomes remain unclear. This study evaluated whether the association between past/current smoking and risk of dementia was mediated by tooth loss.

MATERIALS AND METHODS

This 9-year-follow-up prospective cohort study targeted adults aged ≥65 years. Dementia incidence during 2013-2019, smoking status (never, past/current) in 2010 and the number of remaining teeth (≤19, ≥20) in 2013 were the outcome, exposure and mediator, respectively. We used causal mediation analysis to fit the Cox proportional hazards model and estimated the hazard ratio (HR) and 95% confidence interval (CI) of the natural indirect effect (NIE) of smoking on dementia incidence through tooth loss and their mediated proportions.

RESULTS

Among 32,986 participants (mean age 72.6 years [1 SD = 5.4]; men 48.4%), the dementia incidence during follow-up was 2.11/100 person-years. Tooth loss significantly mediated the association between past/current smoking and dementia incidence; the NIE of fewer remaining teeth for past/current smokers compared to never smokers was HR = 1.03 (95% CI: 1.02-1.05), and the mediated proportion was 18.0%.

CONCLUSIONS

Tooth loss significantly mediates the association between past/current smoking and an increased risk of dementia among older adults.

Higher Cholesterol Absorption Marker at Baseline Predicts Fewer Cardiovascular Events in Elderly Patients Receiving Hypercholesterolemia Treatment: The KEEP Study

BACKGROUND

Higher cholesterol absorption has been reported to be related to a higher incidence of cardiovascular events (CVEs). The KEEP (Kyushu Elderly Ezetimibe Phytosterol) study, a substudy of the EWTOPIA 75 (Ezetimibe Lipid-Lowering Trial on Prevention of Atherosclerotic Cardiovascular Disease in 75 or Older) study, investigated the relationships of cholesterol absorption and synthesis markers with CVEs in older old individuals with hypercholesterolemia, particularly in relation to ezetimibe treatment.

METHODS AND RESULTS

Eligible patients were those aged ≥75 years who had low-density lipoprotein cholesterol ≥140 mg/dL, no history of coronary artery disease, and no recent use of lipid-lowering drugs. Participants were randomly assigned into a diet-only or diet-plus-ezetimibe group. Baseline and 24-week follow-up blood samples were analyzed for cholesterol absorption (eg, campesterol) and synthesis markers (eg, lathosterol). Of 1287 patients, 1061 patients with baseline measurement were analyzed. Over a median follow-up of 4.0 years, 64 CVEs occurred. Higher campesterol levels at baseline were significantly associated with a lower risk of CVEs. After adjustment for sex, age, and treatment, the hazard ratios for the lowest to highest quartile categories of baseline campesterol were 1.00 (reference), 0.59 (95% CI, 0.30-1.17), 0.44 (95% CI, 0.21-0.94), and 0.44 (95% CI, 0.21-0.93), respectively (trend P=0.01). This association persisted after further adjustment for hypertension, diabetes, and other cardiovascular risk factors. Neither interactions with ezetimibe treatment nor mediating effects of the changes in cholesterol absorption markers were observed.

CONCLUSIONS

The KEEP study indicated that higher campesterol levels without lipid-lowering drugs were associated with a lower incidence of CVEs in older old individuals with hypercholesterolemia who were subsequently treated with diet or ezetimibe.

REGISTRATION

URL: https://www.umin.ac.jp; unique identifier: UMIN000017769.

Mediation and interaction of problematic internet use in the relationship between sexual minority status and depressive symptoms: Gender-based analysis

BACKGROUND

Previous studies have demonstrated that sexual minorities are at a higher risk of experiencing depressive symptoms. However, few prior investigations have examined the potential mechanisms involved. This study aimed to employ the four-way decomposition approach that integrates the analysis of mediation and interaction to investigate the potential role of problematic internet use between sexual orientation and depressive symptoms.

METHODS

The participants were recruited through a multi-stage, stratified cluster, and random sampling method in China. Students who identified as "gay or lesbian" and "bisexual" were defined as "sexual minorities". The Young's Internet Addiction Test (IAT) was used to evaluate problematic internet use. The Center for Epidemiologic Studies Depression Scale (CESD-20) was used to evaluate depressive symptoms.

RESULTS

A total of 59,859 adolescents were included in this study, with 30,180 (53.25 %) boys and 29,679 (46.75 %) girls. Of these, 7263 (12.13 %) were identified as sexual minorities. Gender differences were observed in the association between sexual orientation, problematic internet use, and depressive symptoms. The mediating effect of problematic internet use was 28.80 % for boys and 36.84 % for girls, respectively. The interaction effect between problematic internet use and sexual minority status on depressive symptoms was 21.19 % and 9.65 % for boys and girls, respectively.

LIMITATIONS

The current study was limited by the cross-sectional design.

CONCLUSION

These findings suggest that prevention and intervention programs aimed at improving mental health outcomes among sexual minority adolescents should prioritize considering the impact of problematic internet use and potential gender differences.

Molecular pathways in placental-fetal development and disruption

The first trimester of pregnancy ranks high in priority when minimizing harmful exposures, given the wide-ranging types of organogenesis occurring between 4- and 12-weeks' gestation. One way to quantify potential harm to the fetus in the first trimester is to measure a corollary effect on the placenta. Placental biomarkers are widely present in maternal circulation, cord blood, and placental tissue biopsied at birth or at the time of pregnancy termination. Here we evaluate ten diverse pathways involving molecules expressed in the first trimester human placenta based on their relevance to normal fetal development and to the hypothesis of placental-fetal endocrine disruption (perturbation in development that results in abnormal endocrine function in the offspring), namely: human chorionic gonadotropin (hCG), thyroid hormone regulation, peroxisome proliferator activated receptor protein gamma (PPARγ), leptin, transforming growth factor beta, epiregulin, growth differentiation factor 15, small nucleolar RNAs, serotonin, and vitamin D. Some of these are well-established as biomarkers of placental-fetal endocrine disruption, while others are not well studied and were selected based on discovery analyses of the placental transcriptome. A literature search on these biomarkers summarizes evidence of placenta-specific production and regulation of each biomarker, and their role in fetal reproductive tract, brain, and other specific domains of fetal development. In this review, we extend the theory of fetal programming to placental-fetal programming.

Social support and cognitive activity and their associations with incident cognitive impairment in cognitively normal older adults

OBJECTIVES

To explore the associations of social support, and cognitive activity with cognitive impairment incidence, and further examine the mediation effect of cognitive activity on the association between social support and cognitive impairment incidence based on a nationwide elderly Chinese cohort.

METHODS

We collected the participants from an ongoing cohort of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). A total of 9394 older adults aged 65 or more years and free of cognitive impairment who participated in the CLHLS between 2008 and 2018 were included. The information on social support and cognitive activity was collected through a questionnaire. The incident cognitive impairment cases were identified through the Mini-Mental State Examination scale (MMSE). Cox proportional hazard regression models were conducted to calculate the hazard ratios (HRs) and 95% confidence interval (CI) of social support and cognitive activity associated with cognitive impairment. We used casual mediation models to assess the indirect association of cognitive activities underlying the association between social support and cognitive impairment.

RESULTS

The adjusted HRs (95% CI) of incident cognitive impairment were 0.956 (0.932 to 0.980), and 0.895 (0.859 to 0.933) associated with per 1 score increase in social support and cognitive activity score, respectively. Better adherence to social support was associated with a higher cognitive activity score (adjusted β = 0.046, 95% CI[0.032-0.060]). The baseline cognitive activity, as well as the mean cognitive activity at baseline and during the first follow-up wave, mediate the association between social support and the incidence of cognitive impairment, accounting for 11.4% and 12.6% of the total association, respectively. The participants who were aged 80 years or older, or those with mild daily functional limitations gained more benefits in the development of cognitive activity related to social support, leading to a reduction in the risks of cognitive impairment.

CONCLUSION

The results of this nationwide cohort provide consistent evidence linking social support, and cognitive activity to reduced risk of subsequent cognitive impairment incidence. These findings provide additional evidence to inform the social strategies to prevent cognitive impairment incidence in elderly people.

Olfactory Dysfunction and Depression Trajectories in Community-Dwelling Older Adults

BACKGROUND

We examined the relationship between baseline olfactory performance and incident significant depressive symptoms and longitudinal depression trajectories in well-functioning older adults. Inflammation and cognitive status were examined as potential mediators.

METHODS

Older adults (n = 2 125, 71-82 years, 51% female, 37% Black) completed an odor identification task at Year 3 (our study baseline) of the Health, Aging, and Body Composition study. Cognitive assessments, depressive symptoms, and inflammatory markers were ascertained across multiple visits over 8 years. Discrete-time complementary log-log models, group-based trajectory models, and multivariable-adjusted multinomial logistic regression were employed to assess the relationship between baseline olfaction and incident depression and longitudinal depression trajectories. Mediation analysis assessed the influence of cognitive status on these relationships.

RESULTS

Individuals with lower olfaction had an increased risk of developing significant depressive symptoms at follow-up (hazard ratio = 1.04, 95% confidence interval [CI]: 1.00, 1.08). Of the 3 patterns of longitudinal depression scores identified (stable low, stable moderate, and stable high), poorer olfaction was associated with a 6% higher risk of membership in the stable moderate (relative risk ratio [RRR] = 1.06, 95% CI: 1.02, 1.10)/stable high (RRR = 1.06, 95% CI: 1.00, 1.12) groups, compared to the stable low group. Poor cognitive status, but not inflammation, partially mediated the relationship between olfactory performance and incident depression symptom severity.

CONCLUSIONS

Suboptimal olfaction could serve as a prognostic indicator of vulnerability for the development of late-life depression. These findings underscore the need for a greater understanding of olfaction in late-life depression and the demographic, cognitive, and biological factors that influence these relationships over time.

Loneliness, Dementia Status, and Their Association with All-Cause Mortality Among Older US Adults

Background

Loneliness, dementia, and mortality are interconnected.

Objective

We aimed at understanding mediating pathways and interactions between loneliness and dementia in relation to mortality risk.

Methods

The study tested bi-directional relationships between dementia, loneliness, and mortality, by examining both interactions and mediating effects in a large sample of older US adults participating in the nationally representative Health and Retirement Study. Out of≤6,468 older participants selected in 2010, with mean baseline age of 78.3 years and a follow-up time up to the end of 2020, 3,298 died at a rate of 64 per 1,000 person-years (P-Y). Cox proportional hazards and four-way decomposition models were used.

Results

Algorithmically defined dementia status (yes versus no) was consistently linked with a more than two-fold increase in mortality risk. Dementia status and Ln(odds of dementia) were strongly related with mortality risk across tertiles of loneliness score. Loneliness z-score was also linked to an elevated risk of all-cause mortality regardless of age, sex, or race or ethnicity, and its total effect (TE) on mortality was partially mediated by Ln(odds of dementia), z-scored, (≤40% of the TE was a pure indirect effect). Conversely, a small proportion (<5%) of the TE of Ln(odds of dementia), z-scored, on mortality risk was explained by the loneliness z-score.

Conclusions

In sum, dementia was positively associated with all-cause mortality risk, in similar fashion across loneliness score tertiles, while loneliness was associated with mortality risk. TE of loneliness on mortality risk was partially mediated by dementia odds in reduced models.

Impact of lifestyle and psychological resilience on survival among the oldest-old in China: a cohort study

Introduction

Healthy lifestyles and psychological resilience are important factors influencing the life expectancy of the oldest-old (≥80 years). Stratified by urban and rural groups, this study used a 10-year cohort to examine the mechanism of lifestyle and psychological resilience on the survival of the oldest-old in China.

Methods

This study used the China Longitudinal Healthy Longevity Survey datasets spanning from 2008 to 2018, and 9,250 eligible participants were included. The primary outcome variable was all-cause mortality, and independent variables included healthy lifestyle index and psychological resilience. Six covariates were included in the survival analysis and moderation-mediation model, such as gender and annual household income.

Results

This study found that the oldest-old with five healthy lifestyles had the longest survival time, averaging 59.40 months for urban individuals and 50.08 months for rural individuals. As the lifestyle index increased, the survival rate significantly increased. The Cox regression showed that for the urban oldest-old, the lifestyle index served as a protective factor for survival outcomes. However, this effect lost statistical significance among rural oldest-old individuals. For urban oldest-old individuals, psychological resilience significantly mediated and moderated the effect of the lifestyle index on survival status, but the moderating effect was not statistically significant for the rural ones.

Discussion

Overall, healthy lifestyles and psychological resilience can be effective in enhancing the survival of the oldest-old, and there are differences between urban and rural population, so different interventions should be adopted for urban and rural areas to achieve longer life in China.

Hospital-treated prevalent infections, the plasma proteome and incident dementia among UK older adults

The plasma proteome can mediate the association of hospital-treated infections with dementia incidence. We screened up to 37,269 UK Biobank participants aged 50-74 years for the presence of a prevalent hospital-treated infection, subsequently tested as a predictor for ≤1,463 plasma proteins and dementia incidence. Four-way decomposition models decomposed infection-dementia total effect into pure mediation, pure interaction, neither or both through the plasma proteome. Hospital-treated infections increased dementia two-fold. The strongest mediation effect was through the growth differentiation factor 15 (GDF15) protein. Top 17 proteomic mediators explained collectively 5% of the total effect, while pathway analysis of all mediators (k = 221 plasma proteins) revealed top pathways including the immune system, signal transduction, metabolism, disease and metabolism of proteins, with the GDF15 cluster reflecting most strongly the "transmembrane receptor protein tyrosine kinase signaling pathway". The association of hospital-treated infections with dementia was partially mediated through GDF15 and other plasma proteomic markers.

Perceived Safety, Not Perceived Legality, Mediates the Relationship Between Cannabis Legalization and Drugged Driving

Cannabis legalization has rapidly spread throughout the United States and is associated with multiple public health outcomes, including driving under the influence of cannabis (DUIC). To improve understanding of the relationship between legalization and DUIC, we tested two potential mediators of this relationship: perceived safety and perceived legality of driving high. We analyzed data from 1,236 current (past 30-day) cannabis users who were recruited from states with recreational, medical only, or no legal cannabis between 2016 and 2017 using address-based and social media samples. Using a generalized linear model and adjusting for cannabis legalization, demographics, living in a state with a cannabis-specific drugged driving law, frequency of cannabis use, and weights, we found that perceived safety (risk ratio [RR] = 2.60, 95% CI [1.88, 3.58]), but not perceived legality (RR = 0.96, 95% CI [0.67, 1.37]), was significantly associated with DUIC. Perceived safety mediated the relationship between legalization and DUIC (Coeff: -0.12, 95% CI [-0.23, -0.01]). Models stratified by frequency of cannabis use yielded results consistent with those of pooled models except that, for frequent users, cannabis-specific driving laws were associated with a significantly lower risk of DUIC (RR = 0.64, 95% CI [0.44, 0.92]). Agencies developing cannabis-focused drugged driving educational campaigns should consider the potential role of perceived safety of driving high in DUIC campaigns.

Impaired lung function in multiple sclerosis: a single-center observational study in 371 persons

INTRODUCTION

Abnormal lung function in people with multiple sclerosis (PwMS) could be considered as the result of muscle weakness or MS-specific structural central nervous system (CNS) abnormalities as a precipitant factor for the worsening of motor impairment or cognitive symptoms.

METHODS

This is a cross-sectional observational study in PwMS. Forced spirometry was conducted, and normative metrics of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and the relation FEV1/FVC were calculated. Qualitative and quantitative brain magnetic resonance imaging (MRI) examinations were carried out.

RESULTS

A total of 371 PwMS were included in the study. Of those, 196 (53%) had RRMS, 92 (25%) SPMS, and 83 (22%) PPMS. Low FVC and FEV1 was present in 16 (8%), 16 (19%), and 23 (25%) of the patients in the RRMS, PPMS, and SPMS, respectively. PwMS with T2-FLAIR lesions involving the corpus callosum (CC) had a significantly higher frequency of abnormally low FVC and FEV1 (OR 3.62; 95% CI 1.33-9.83; p = 0.012) than patients without lesions in that region. This association remained significant in the RRMS group (OR 10.1; 95% CI 1.3-67.8; p 0.031) when the model excluded PPMS and SPMS. According to our study, for every increase of 1 z score of FVC, we observed an increase of 0.25 cm3 of hippocampal volume (β 0.25; 95% CI 0.03-0.47; p 0.023) and 0.43 cm3 of left hippocampus volume (β 0.43; 95% CI 0.16-0.71; p 0.002).

CONCLUSIONS

We observed an incremental prevalence of abnormally low pulmonary function tests that parallels a sequence from more early relapsing courses to long-standing progressive courses (RRMS to PPMS or SPMS).

The psychological legacy of past obesity and early mortality: evidence from two longitudinal studies

BACKGROUND

We test a novel 'weight scarring' hypothesis which suggests that past obesity is associated with impairments in current psychological well-being and this increases risk of negative physical health outcomes associated with obesity. Across two nationally representative studies, we tested whether past obesity is associated with current psychological outcomes and whether these psychological outcomes explain the association between past obesity and subsequent early mortality.

METHODS

Data were from the National Health and Nutrition Examination Survey (NHANES) (n = 29,047) and the Health and Retirement Study (HRS) (n = 11,998). Past obesity was defined based on maximum lifetime weight in NHANES and the highest weight from past study waves in the HRS. Across both studies, current depressive symptoms were analysed. A set of 10 additional well-being measures were combined to produce an 'index of impaired well-being' in HRS. Subsequent all-cause mortality was examined using National Deaths Index records in NHANES and household interviews in HRS. Linear or logistic regression, Cox proportional hazard regression, and causal mediation models were used.

RESULTS

We found that past obesity was associated with greater current depressive symptoms after controlling for current weight status and in analyses limited to those who were no longer classified as having obesity in NHANES (β = 0.17; 95% CI: 0.13, 0.22) and HRS (β = 0.20; 95% CI: 0.08, 0.31). In HRS, past obesity was also associated with a range of current negative psychological outcomes, including an index of impaired psychological well-being (β = 0.16; 95% CI: 0.05, 0.27). Past obesity was associated with a higher risk of early mortality in both NHANES and HRS (HR = 1.31; 95% CI: 1.16, 1.48 and HR = 1.34; 95% CI: 1.20, 1.50, respectively). Depressive symptoms explained 6% (95% CI: 0.01, 0.10) and 5% (95% CI: 0.01, 0.09) of the association between past obesity and premature mortality in NHANES and HRS, respectively. Impaired psychological well-being partly mediated the association between past obesity and premature mortality by 10% (95% CI: 0.04, 0.16) in HRS.

CONCLUSIONS

Our findings suggest that there may be a psychological legacy of past obesity that is associated with raised mortality risk. Ensuring people with obesity receive psychological support even after experiencing weight loss may be important.

Prenatal Exposure to PFAS, Associations with Preterm Birth and Modification by Maternal Estrogen Levels: The Maoming Birth Study

BACKGROUND

Estrogens play a critical role in parturition, and poly- and perfluoroalkyl substances (PFAS), which have estrogenic effects, have been associated with preterm birth. However, the impact of estrogens on the association between PFAS and preterm birth is unknown.

OBJECTIVE

The objective of this study is to investigate if estrogens modified the association between PFAS and preterm birth, using a nested case-control study design.

METHODS

A total of 371 preterm births and 508 controls were selected from a birth cohort study in China between 2016 and 2018. Perfluorobutanoic acid (PFBA), perfluorohexanesulfonic acid (PFHxS) and its branched isomer, perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and its branched isomer, and perfluorononanoic acid (PFNA) were quantified in maternal serum (mean gestational age of 32 wk). Estradiol and estriol were quantified in cord serum. Preterm birth was defined as live delivery at < 37 gestational weeks. Causal mediation analysis was used to estimate the mediation and interaction effects of estrogen on the association between PFAS and preterm birth. Latent profile analysis was used to identify important estrogen profiles. Multiple linear regression was used to estimate associations between PFAS and preterm birth and interactions between PFAS and estrogens on preterm birth.

RESULTS

Overall, higher odds ratios (ORs) of preterm birth were associated with each 1 ln-unit PFAS increase: PFBA [1.20, 95% confidence interval (CI): 1.14, 1.26], PFNA (1.30, 95% CI: 1.21, 1.39), PFOA (1.98, 95% CI: 1.54, 2.55), and PFOS (1.91, 95% CI: 1.76, 2.07) and its branched isomer (1.91, 95% CI: 1.90, 1.92). We detected statistically significant interactions between cord estradiol and PFAS on preterm birth, while no mediation effects of cord estrogen were observed. The ORs of PFOS (4.29, 95% CI: 1.31, 8.25), its branched isomer (6.71, 95% CI: 1.06, 11.91), and preterm birth were greater for participants with high cord estrogen levels than for participants with low cord estrogen levels.

DISCUSSION

Our findings suggest that estrogen modified the association between maternal PFAS exposure and preterm birth. Further studies on maternal PFAS exposure and preterm birth, taking interaction effects of cord estrogens into account, are warranted. https://doi.org/10.1289/EHP11377.

The interaction and mediation effects between the host genetic factors and Epstein-Barr virus VCA-IgA in the risk of nasopharyngeal carcinoma

Previous studies have demonstrated strong associations between host genetic factors and Epstein-Barr virus (EBV) VCA-IgA with the risk of nasopharyngeal carcinoma (NPC). However, the specific interplay between host genetics and EBV VCA-IgA on NPC risk is not well understood. In this two-stage case-control study (N = 4804), we utilized interaction and mediation analysis to investigate the interplay between host genetics (genome-wide association study-derived polygenic risk score [PRS]) and EBV VCA-IgA antibody level in the NPC risk. We employed a four-way decomposition analysis to assess the extent to which the genetic effect on NPC risk is mediated by or interacts with EBV VCA-IgA. We consistently found a significant interaction between the PRS and EBV VCA-IgA on NPC risk (discovery population: synergy index [SI] = 2.39, 95% confidence interval [CI] = 1.85-3.10; replication population: SI = 3.10, 95% CI = 2.17-4.44; all pinteraction  < 0.001). Moreover, the genetic variants included in the PRS demonstrated similar interactions with EBV VCA-IgA antibody. We also observed an obvious dose-response relationship between the PRS and EBV VCA-IgA antibody on NPC risk (all ptrend  < 0.001). Furthermore, our decomposition analysis revealed that a substantial proportion (approximately 90%) of the genetic effects on NPC risk could be attributed to host genetic-EBV interaction, while the risk effects mediated by EBV VCA-IgA antibody were weak and statistically insignificant. Our study provides compelling evidence for an interaction between host genetics and EBV VCA-IgA antibody in the development of NPC. These findings emphasize the importance of implementing measures to control EBV infection as a crucial strategy for effectively preventing NPC, particularly in individuals at high genetic risk.

History of Gestational Diabetes and Incident Nonalcoholic Fatty Liver Disease: The Kangbuk Samsung Health Study

INTRODUCTION

We examined the relationship between a previous history of gestational diabetes mellitus (pGDM) and risk of incident nonalcoholic fatty liver disease (NAFLD) and investigated the effect of insulin resistance or development of diabetes as mediators of any association.

METHODS

We performed a retrospective cohort study of 64,397 Korean parous women without NAFLD. The presence of and the severity of NAFLD at baseline and follow-up were assessed using liver ultrasonography. Cox proportional hazards models were used to determine adjusted hazard ratios for incident NAFLD according to a self-reported GDM history, adjusting for confounders as time-dependent variables. Mediation analyses were performed to examine whether diabetes or insulin resistance may mediate the association between pGDM and incident NAFLD.

RESULTS

During a median follow-up of 3.7 years, 6,032 women developed incident NAFLD (of whom 343 had moderate-to-severe NAFLD). Multivariable adjusted hazard ratios (95% confidence intervals) comparing women with time-dependent pGDM with the reference group (no pGDM) were 1.46 (1.33-1.59) and 1.75 (1.25-2.44) for incident overall NAFLD and moderate-to-severe NAFLD, respectively. These associations remained significant in analyses restricted to women with normal fasting glucose <100 mg/dL or that excluded women with prevalent diabetes at baseline or incident diabetes during follow-up. Diabetes and insulin resistance (Homeostatic Model Assessment for Insulin Resistance) each mediated <10% of the association between pGDM and overall NAFLD development.

DISCUSSION

A previous history of GDM is an independent risk factor for NAFLD development. Insulin resistance, measured by the Homeostatic Model Assessment for Insulin Resistance, and development of diabetes each explained only <10% of the association between GDM and incident NAFLD.

Mentally-passive sedentary behavior and incident depression: Mediation by inflammatory markers

BACKGROUND

Sedentary behavior (SB; time spent sitting, as distinct from lack of exercise or physical activity) is associated with depression, yet little is known about the relationship between different types of SB (e.g., mentally-passive versus mentally-active) with depression and potential biological mediators of these associations.

METHODS

We used cohort data from the 1958 National Child Development Study (n = 4607; 50.4 % women), conducted in UK, employing the 44 y and 46 y waves as baseline, and the 50 y and 55 y waves as follow-up. Participants reported time spent in TV viewing and watching videos (mentally-passive SB); and, time sitting while doing light activities such as deskwork or driving a car during worktime (mentally-active SB). Depression diagnosis was self-reported during the initial and follow-up waves. Waist circumference, C-reactive protein, and glycated hemoglobin were examined as potential mediators.

RESULTS

Mentally-passive SB was associated with incident depression (HR: 1.43; 95%CI: 1.19; 1.71), while there was no association for mentally-active SB. Waist circumference (coefficient: -0.03; 95%CI: -0.05; -0.01; 9.2 %) and C-reactive protein (coefficient: -0.03; 95%CI: -0.04; -0.01; 8.3 %), but not glycated hemoglobin, partly mediated the association for mentally-passive SB.

CONCLUSIONS

In the relationship of mentally-passive SB with incident depression, the mediating contributions of waist circumference and C-reactive protein point to possible inflammatory-related mechanisms.

Effects of leisure activities and general health on the survival of older people: a cohort study in China

Objective

This study aimed to examine the influence of physical and cognitive leisure activities on the survival of older adults in China, while also exploring the potential mediating and moderating effects of general health.

Methods

This study utilized the China Longitudinal Healthy Longevity Survey (CLHLS) datasets spanning from 2008 to 2018, and 10,347 eligible participants were included. The primary study outcome was all-cause mortality, and independent variables included physical leisure activities (PLA), cognitive leisure activities (CLA), and self-rated general health. Three sets of covariates were adjusted, including socio-demographic characteristics, health behaviors, and health status.

Results

The longest survival time was the older people participating in PLA & CLA (mean = 50.31 months), while those participating in neither exhibited the lowest (mean = 29.60 months). Significant differences in survival status were observed in different types of leisure activities participation (Log-rank test, Chi-square = 576.80, p < 0.001). Cox regression indicated that PLA (HR = 0.705, 95% CI: 0.651-0.764), CLA (HR = 0.872, 95% CI: 0.816-0.933), and the both PLA & CLA (HR = 0.700, 95% CI: 0.656-0.747) were protective factors for the survival. Additionally, general health significantly moderated the relationship between PLA and reduced mortality risk (Coefficient = -0.089, p = 0.042). While CLA indirectly influenced the survival through general health (Coefficient = -0.023, p < 0.001). For the older people participating in PLA and CLA, general health played mediating (Coefficient = -0.031, p < 0.001) and moderating (Coefficient = -0.026, p = 0.013) role in the relationship between leisure activities and survival.

Conclusion

Leisure activities and self-rated general health were important predictors of survival of the older adults, and general health exhibited a mediator and moderator in the relationship between leisure activities and survival status.

Handgrip strength, physical activity and incident mild cognitive impairment and dementia

OBJECTIVE

We analyzed the mediating role of handgrip strength in the association between moderate to vigorous physical activity and incident mild cognitive impairment and dementia.

METHODS

We used prospective data from 14 European countries participating in the Survey of Health, Ageing, and Retirement in Europe. 19,686 participants free of dementia and mild cognitive impairment (64.9 ± 8.7 years) were followed up for a mean of 10.2 years. Moderate to vigorous physical activity was self-reported, and handgrip strength was assessed with a dynamometer. Mild cognitive impairment was defined as 1.5 standard deviations below the mean of the standardized global cognition score, while dementia was determined by physician diagnosis. Gender, age, country, education, presence of chronic diseases, depressive symptoms, limitations in activities of daily living, body mass index, and baseline cognitive levels were used as covariates. Cox proportional hazards as well as mediation models were used.

RESULTS

Moderate to vigorous physical activity for at least 1 day per week was independently associated with lower incident mild cognitive impairment (HR: 0.85; 95%CI: 0.74-0.98). A 10 % increase in handgrip strength was associated a 6 % lower hazard for incident mild cognitive impairment (0.94; 0.92-0.97) and 5 % lower hazard for incident dementia (0.95; 0.93-0.98). Handgrip strength partly mediated the association of moderate to vigorous physical activity with mild cognitive impairment (Coefficient: 0.03; 95%CI: 0.01-0.05; 17.9 %).

CONCLUSIONS

Physical activity is independently associated with a lower incidence of mild cognitive impairment.

Does stroke-associated pneumonia play an important role on risk of in-hospital mortality associated with severe stroke? A four-way decomposition analysis of a national cohort of stroke patients

BACKGROUND

Severe strokes and stroke-associated pneumonia (SAP) have long been associated with poorer patient health outcomes, for example, in-hospital mortality. However, it is unclear what role SAP plays in the risk of in-hospital mortality associated with a severe stroke at admission.

METHODS

Using the Sentinel Stroke National Audit Program data on stroke admissions (2013-2018) in England and Wales, we modeled the "total" effect for severe stroke on risk of in-hospital mortality. Through four-way decomposition methodology, we broke down the "total" observed risk into four components. The direct "severity on outcome only" effect, the pure indirect effect of severity mediated via SAP only, the interaction between severity and SAP when mediation is not present, and when mediation via SAP is present.

RESULTS

Of 339,139 stroke patients included, 9.4% had SAP and 15.6% died in hospital. Of SAP patients, 45% died versus 12% of non-SAP patients. The risk ratio for in-hospital mortality associated with severe versus mild/moderate stroke (i.e. total effect) was 4.72 (95% confidence interval: 4.60-4.85). Of this, 43%-increased risk was due to additive SAP interaction, this increased to 50% for "very severe" stroke. The remaining excess relative risk was due to the direct severity on outcome effect only, that is, there was no evidence here for a mediation effect via SAP.

CONCLUSION

SAP was associated with a higher mortality in severe stroke patients. Prioritizing SAP prevention in severe stroke patients may improve in-hospital survival. Our results suggest that in severe stroke patients avoiding SAP might result in an up to 43% reduction in mortality.

Association of Long-term Exposure to Air Pollution and Dementia Risk: The Role of Homocysteine, Methionine, and Cardiovascular Burden

BACKGROUND AND OBJECTIVES

Growing evidence links air pollution with dementia risk, but the biological mechanisms are largely unknown. We investigated the role played by homocysteine (tHcy) and methionine in this association and explored whether this could be explained by cardiovascular diseases (CVDs).

METHODS

Data were extracted from the ongoing Swedish National study on Aging and Care in Kungsholmen (SNAC-K), a longitudinal population-based study. At baseline, 2,512 dementia-free participants were examined up to 2013 (mean follow-up: 5.18 ± 2.96 years). Two air pollutants (particulate matter ≤2.5 μm [PM2.5] and nitrogen oxides [NOx]) were assessed yearly from 1990 until 2013 using dispersion models at residential addresses. The hazard ratio of dementia over air pollution levels was estimated using Cox models adjusted for age, sex, education, smoking, socioeconomic status, physical activity, retirement age, creatinine, year of assessment, and the use of supplements. The total effect of air pollutants on dementia was decomposed into 4 pathways involving tHcy/methionine: (1) direct effect; (2) indirect effect (mediation); (3) effect due to interaction; and (4) effect due to both mediation and interaction. To test whether the association was independent from CVDs (ischemic heart disease, atrial fibrillation, heart failure, and stroke), we repeated the analyses excluding those individuals who developed CVDs.

RESULTS

The mean age of the study participants was 73.4 years (SD: 10.4), and 62.1% were female individuals. During an average period of 5 years (mean: 5.18; SD: 2.96 years), 376 cases with incident dementia were identified. There was a 70% increased hazard of dementia per unit increase of PM2.5 during the 5 years before baseline (hazard ratio [HR]: 1.71; 95% CI 1.33-2.09). Overall, 50% (51.6%; 95% CI 9.0-94.1) of the total effect of PM2.5 on dementia was due to mediation of tHcy (6.6%; 95% CI 1.6-11.6) and/or interaction (47.8%; 95% CI 4.9-91.7) with tHcy and 48.4% (p = 0.03) to the direct effect of PM2.5 on dementia. High levels of methionine reduced the dementia hazard linked to PM2.5 by 31% (HR: 0.69; 95% CI 0.56-0.85) with 24.8% attributable to the interaction with methionine and 25.9% (p = 0.001) to the direct effect of PM2.5. No mediation effect was found through methionine. Attenuated results were obtained for NOx. Findings for tHcy were attenuated after excluding those who developed CVDs, while remained similar for methionine.

DISCUSSION

High levels of homocysteine enhanced the dementia risk attributed to air pollution, while high methionine concentrations reduced this risk. The impact of homocysteine on cardiovascular conditions partly explains this association. Alternative pathways other than cardiovascular mechanisms may be at play between methionine and dementia.

The mediation role of social network size and perception in the association between physical activity and depressive symptoms: a prospective analysis from the SHARE study

OBJECTIVES

To investigate the mediating role of social network size and perceived quality in the associations of physical activity with quality of life and depressive symptoms in middle-aged and older adults.

METHOD

We analyzed information of 10,569 middle-aged and older adults from waves 2 (2006-2007), 4 (2011-2012), and 6 (2015) of the Survey of Health, Ageing, and Retirement in Europe study (SHARE). Data on physical activity (moderate and vigorous intensities), social network (size and quality), depressive symptoms (EURO-D scale), and quality of life (CASP) were self-reported. Sex, age, country of residency, schooling, occupational status, mobility, and baseline values of the outcome were used as covariates. We created mediation models to test the mediating effect of social network size and quality in the association between physical activity and depressive symptoms.

RESULTS

Social network size partly mediated the association between vigorous physical activity and depressive symptoms (7.1%; 95%CI: 1.7-12.6) as well as the association between moderate (9.9%; 1.6-19.7) and vigorous (8.1%; 0.7-15.4) physical activity and quality of life. Social network quality did not mediate any of the associations tested.

CONCLUSION

We conclude that social network's size, but not satisfaction, mediates part of the association of physical activity with depressive symptoms and quality of life in middle-aged and older adults. Future physical activity interventions among middle-aged and older adults should consider increasing social interactions to facilitate benefits for mental health-related outcomes.

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.

Does financial hardship associate with abnormal quantitative myocardial perfusion and major adverse cardiovascular event?

BACKGROUND

Data on impact of financial hardship on coronary artery disease (CAD) remain incomplete.

METHODS

Consecutive subjects referred for clinical rest/stress cardiac positron emission tomography (PET) were enrolled. Financial hardship is defined as patients' inability to pay for their out-of-pocket expense for cardiac PET. Abnormal cardiac PET is defined as at least moderate relative perfusion defects at stress involving > 10% of the left ventricle or global coronary flow reserve ≤ 2.0. Patients were followed for major adverse cardiovascular event (MACE) comprised of all-cause mortality, non-fatal myocardial infarction, and late coronary revascularization.

RESULTS

We analyzed a total of 4173 patients with mean age 65.6 ± 11.3 years, 72.2% men, and 93.6% reported as having medical insurance. Of these, 504 (12.1%) patients had financial hardship. On multivariable analysis, financial hardship associated with abnormal cardiac PET (odds ratio 1.377, p = 0.004) and MACE (hazard ratio 1.432, p = 0.010) and its association with MACE was mostly through direct effect with small proportion mediated by abnormal cardiac PET or known CAD.

CONCLUSION

Among patients referred for cardiac rest/stress PET, financial hardship independently associates with myocardial perfusion abnormalities and MACE; however, its effect on MACE is largely not mediated by abnormal myocardial perfusion or known CAD suggesting distinct impact of financial hardship beyond traditional risk factors and CAD that deserves attention and intervention to effectively reduced adverse outcomes. Having medical insurance does not consistently protect from financial hardship and a more preventive-oriented restructuring may provide better outcomes at lower cost.

Decomposing interaction and mediating effects of race/ethnicity and circulating blood levels of cystatin C on cognitive status in the United States health and retirement study

Background and objectives

Elevated circulating cystatin C is associated with cognitive impairment in non-Hispanic Whites, but its role in racial disparities in dementia is understudied. In a nationally representative sample of older non-Hispanic White, non-Hispanic Black, and Hispanic adults in the United States, we use mediation-interaction analysis to understand how racial disparities in the cystatin C physiological pathway may contribute to racial disparities in prevalent dementia.

Methods

In a pooled cross-sectional sample of the Health and Retirement Study (n = 9,923), we employed Poisson regression to estimate prevalence ratios and to test the relationship between elevated cystatin C (>1.24 vs. ≤1.24 mg/L) and impaired cognition, adjusted for demographics, behavioral risk factors, other biomarkers, and chronic conditions. Self-reported racialized social categories were a proxy measure for exposure to racism. We calculated additive interaction measures and conducted four-way mediation-interaction decomposition analysis to test the moderating effect of race/ethnicity and mediating effect of cystatin C on the racial disparity.

Results

Overall, elevated cystatin C was associated with dementia (prevalence ratio [PR] = 1.2; 95% CI: 1.0, 1.5). Among non-Hispanic Black relative to non-Hispanic White participants, the relative excess risk due to interaction was 0.7 (95% CI: -0.1, 2.4), the attributable proportion was 0.1 (95% CI: -0.2, 0.4), and the synergy index was 1.1 (95% CI: 0.8, 1.8) in a fully adjusted model. Elevated cystatin C was estimated to account for 2% (95% CI: -0, 4%) for the racial disparity in prevalent dementia, and the interaction accounted for 8% (95% CI: -5, 22%). Analyses for Hispanic relative to non-white participants suggested moderation by race/ethnicity, but not mediation.

Discussion

Elevated cystatin C was associated with dementia prevalence. Our mediation-interaction decomposition analysis suggested that the effect of elevated cystatin C on the racial disparity might be moderated by race/ethnicity, which indicates that the racialization process affects not only the distribution of circulating cystatin C across minoritized racial groups, but also the strength of association between the biomarker and dementia prevalence. These results provide evidence that cystatin C is associated with adverse brain health and this effect is larger than expected for individuals racialized as minorities had they been racialized and treated as non-Hispanic White.

Sex Differences in Survival from Neuroendocrine Neoplasia in England 2012–2018: A Retrospective, Population-Based Study

Pre-clinical studies have suggested sex hormone signalling pathways may influence tumorigenesis in neuroendocrine neoplasia (NEN). We conducted a retrospective, population-based study to compare overall survival (OS) between males and females with NEN. A total of 14,834 cases of NEN diagnosed between 2012 and 2018, recorded in England’s National Cancer Registry and Analysis Service (NCRAS), were analysed. The primary outcome was OS with 5 years maximum follow-up. Multivariable analysis, restricted mean survival time and mediation analysis were performed. Appendiceal, pulmonary and early-stage NEN were most commonly diagnosed in females; stomach, pancreatic, small intestinal, colonic, rectal and later-stage NEN were more often diagnosed in males. Females displayed increased survival irrespective of the stage, morphology or level of deprivation. On average, they survived 3.62 (95% CI 1.73–5.90) to 10.26 (6.6–14.45) months longer than males; this was statistically significant in NEN of the lung, pancreas, rectum and stomach (p < 0.001). The stage mediated improved survival in stomach, lung, and pancreatic NEN but not in rectal NEN. The reasons underlying these differences are not yet understood. Overall, females diagnosed with NEN tend to survive longer than males, and the stage at presentation only partially explains this. Future research, as well as prognostication and treatment, should consider sex as an important factor.