Estimation and Inference for the Mediation Proportion

Multigenerational association between smoking and autism spectrum disorder: findings from a nationwide prospective cohort study

Animal studies have shown that exposure to cigarette smoke during pregnancy can induce neurobehavioral anomalies in multiple subsequent generations. However, little work has examined such effects in humans. We examined the risk of grandchild autism spectrum disorder (ASD) in association with grandmother's smoking during pregnancy, using data from 53 562 mothers and grandmothers and 120 267 grandchildren in Nurses' Health Study II. In 1999, Nurses' Health Study II participants with children reported on their mothers' smoking. Grandchildren's ASD diagnoses were reported by the mothers in 2005 and 2009. Among grandmothers, 13 383 (25.0%) smoked during pregnancy, and 509 (0.4%) grandchildren were diagnosed with ASD. The adjusted odds ratio for ASD for grandmother smoking during pregnancy was 1.52 (95% CI, 1.06-2.20). Results were similar with direct grandmother reporting in 2001 of her smoking during pregnancy from the Nurses' Mothers Cohort Study subgroup (n = 22 167 grandmothers, n = 49 917 grandchildren) and were stronger among grandmothers who smoked ≥15 cigarettes per day during pregnancy (adjusted odds ratio = 1.93 [95% CI, 1.10-3.40]; n = 1895 grandmothers, n = 4212 grandchildren). Results were similar when we adjusted for mother's smoking during pregnancy. There was no association with grandfather's smoking as reported by the grandmother. Our results suggest a potential persistent impact of gestational exposure to environmental insults across 3 generations.

A naturalistic examination of feeling fat: Characteristics, predictors, and the relationship with eating disorder behaviors

OBJECTIVE

Although literature implicates feeling fat in the maintenance of binge-spectrum eating disorders (EDs; e.g., bulimia nervosa, binge-ED), research in this area is small, nascent, and relies on retrospective self-report. The current study sought to understand the temporal pattern of feeling fat and its role as a precipitant and consequence of ED behaviors.

METHODS

Totally 106 treatment-seeking adults with binge-spectrum EDs completed 7-14-day ecological momentary assessments. They rated feeling fat, negative affect states, and reported on ED behaviors six times per day. Multilevel models evaluated whether feeling fat mediates prospective links between negative affect states and ED behaviors, assessed if negative affect states mediate the prospective association of feeling fat on ED behaviors, and examined the bidirectional prospective association between feeling fat and ED behaviors.

RESULTS

Feeling fat was highest in the early morning (6-8:59 a.m.). Individuals with binge-ED-spectrum EDs demonstrated greater variability in feeling fat than those with bulimia nervosa-spectrum EDs who had stable and high levels of feeling fat. Guilt, sadness, anxiety, and the overall NA at Time 2 mediated the prospective associations between at Time 1 feeling fat and Time 3 dietary restraint, actual dietary restriction, and compensatory exercise. There was a bidirectional prospective association between feeling fat and binge eating.

DISCUSSION

Feeling fat serves as a proximal predictor and mediator of the prospective association between guilt and binge eating. Feeling fat and binge eating mutually reinforce each other.

PUBLIC SIGNIFICANCE

Little is understood regarding the experience of feeling fat in natural environments among individuals with binge-spectrum eating disorders. We found that the risk for having the experience of feeling fat is high in the morning and evening. Feeling fat triggers guilt, anxiety, and sadness which in turn, increases engagement in dietary restraint/restriction and compensatory exercise. Feeling fat also triggers binge eating, and binge eating leads to feelings of fatness.

Associations of soy product intake with all-cause, cardiovascular disease and cancer mortality: Guangzhou Biobank Cohort Study and updated meta-analyses

PURPOSE

We examined the associations of soy product intake with all-cause, cardiovascular disease (CVD), and cancer mortality and mediations through CVD risk factors based on the Guangzhou Biobank Cohort Study (GBCS), and conducted updated meta-analyses.

METHODS

A total of 29,825 participants aged 50 + years were included. Causes of death were identified through record linkage. Soy product intake was assessed by food frequency questionnaire. Cox proportional hazards regression was used to analyze the associations between soy product intake and mortality, yielding hazard ratios (HRs) and 95% confidence intervals (CIs). Mediation analyses with CVD risk factors as mediators, and updated meta-analyses were conducted.

RESULTS

During 454,689 person-years of follow-up, 6899 deaths occurred, including 2694 CVD and 2236 cancer. Participants who consumed soy product of 1-6 portions/week, versus no consumption, had significantly lower risks of all-cause and CVD mortality (adjusted HR (95% CI) 0.91 (0.86, 0.97) and 0.87 (0.79, 0.96), respectively). In participants who consumed soy product of ≥ 7 portions/week, the association of higher intake with lower CVD mortality was modestly mediated by total cholesterol (4.2%, 95% CI 1.0-16.6%). Updated meta-analyses showed that the highest level of soy product intake, versus the lowest, was associated with lower risks of all-cause and CVD mortality (pooled HR (95% CI) 0.92 (0.88, 0.96) and 0.92 (0.87, 0.98), respectively).

CONCLUSION

Moderate and high soy product intake were associated with lower risks of all-cause and CVD mortality. Our findings provide support for current dietary guidelines recommending moderate soy product intake, and contribute additional evidence regarding the potential protective effects of high soy product intake.

The Relationship between Big Five Personality Traits and Depression in the German-Speaking D-A-CH Region Including an Investigation of Potential Moderators and Mediators

Considerable evidence links the "Big Five" personality traits (neuroticism, extroversion, conscientiousness, agreeableness, and openness) with depression. However, potential mediating and moderating factors are less well understood. We utilized data from a cross-sectional survey of 3065 German-speaking adults from the D-A-CH region to estimate multivariable-adjusted odds ratios and 95% confidence intervalsbetween personality traits and lifetime prevalence of depression (overall and stratified by sex and age). We further explored proportions mediated by psychosocial factors optimism, empathy, perspective-taking, work-life balance, and interpersonal trust. High levels of neuroticism were associated with more than two-fold higher odds of depression, whereas higher levels of conscientiousness were associated with approximately 30% lower odds of depression. The association with neuroticism persisted in all investigated subgroups; apparently, stronger associations for females and participants aged ≥60 years did not correspond to statistically significant interactions. Overall and across all strata, the association of neuroticism with depression appeared to be mediated in part by the considered psychosocial factors; optimism explained the largest proportion of the association. Our results provide empirical evidence for the dynamic predisposition model. Further investigations of these relationships are warranted in longitudinal data with more precise outcome assessments.

Lifestyle modifies the associations of early-life smoking behaviors and genetic susceptibility with type 2 diabetes: A prospective cohort study involving 433,872 individuals from UK Biobank

BACKGROUND

To investigate whether and what lifestyle factors in later life modify the associations of early-life smoking behaviors and genetic susceptibility with type 2 diabetes (T2D).

METHODS

In the UK Biobank, in utero tobacco exposure (n = 354,493) and age of smoking initiation (n = 353,557) were self-reported. A composite lifestyle score was calculated based on diet, physical activity, nicotine exposure, sleep duration, and BMI. Hazard ratio (HR) and absolute risk difference (ARD) were used to estimate the associations of early-life smoking behaviors and genetic risk with incident T2D, as well as the effect modification of the lifestyle score.

RESULTS

During a median follow-up of 14.6 years, the HRs (95 % CIs) of T2D for in utero tobacco exposure, and smoking initiation in adulthood, adolescence, and childhood, compared with no smoking behavior, were 1.19 (1.16-1.23), 1.34 (1.29-1.39), 1.58 (1.53-1.64), 2.22 (2.11-2.32), respectively (P for trend<0.001). Early-life smoking behaviors and high genetic risk (vs no smoking behavior and low genetic risk) were associated with a 302%-593 % higher T2D risk (P for additive interaction<0.05). Compared to participants with early-life smoking behaviors, high genetic risk, and an unfavorable lifestyle, those who adhered to a favorable lifestyle had a lower T2D risk in all subgroups (HRs from 0.05 to 0.36 and ARD from -14.97 % to -9.51 %), with the highest ARD attributable to lifestyle in participants with early-life smoking behaviors and high genetic risk.

CONCLUSIONS

The T2D risk associated with early-life smoking behaviors and genetic risk was modified by a favorable lifestyle.

Association of ultraprocessed food consumption with risk of microvascular complications among individuals with type 2 diabetes in the UK Biobank: a prospective cohort study

BACKGROUND

The poor nutritional characteristics and potentially harmful molecules in ultraprocessed foods (UPFs) are risk factors for diabetic microvascular complications. However, the evidence regarding UPFs and diabetic microvascular complications remains limited.

OBJECTIVES

We aimed to evaluate the associations between UPF consumption and risk of diabetic microvascular complications, to examine the underlying biological pathways (e.g., inflammation and lipid profile), and to identify whether the associations differ by type of UPF dietary patterns.

METHODS

We included a prospective cohort of UK Biobank participants with type 2 diabetes (T2D) having at least one 24-h dietary recall (N = 5685). UPFs were defined using the Nova classification. Principal component analysis was used to derive UPF consumption patterns. Associations of UPFs and their consumption patterns with microvascular complications were assessed using Cox proportional hazards regression models. Mediation analyses were used to estimate the mediating effects of 22 biomarkers.

RESULTS

During a median of 12.7 y of follow-up, 1243 composite microvascular complications events occurred (599 diabetic retinopathy, 237 diabetic neuropathy, and 662 diabetic kidney disease events). Five consumption patterns were identified (spread and bread, cereal prepared with liquids, dairy-based products, sugary beverage and snack, and mixed beverage and savory snack patterns). A 10% increment in the proportion of UPF was associated with higher hazards of the composite microvascular complications (hazard ratio [HR]: 1.08; 95% confidence interval [CI]: 1.03, 1.13) and diabetic kidney disease (HR: 1.13; 95% CI: 1.06, 1.20). Triglycerides, C-reactive protein, and body mass index collectively explained 22.0% (9.6%-43.0%) of the association between UPF intake and composite microvascular complications. Pattern high in mixed beverage and savory snack was associated with a higher risk of composite microvascular complications.

CONCLUSIONS

Higher UPF consumption was associated with higher risks of diabetic microvascular complications, and the association was partly mediated through multiple potential ways.

Adding salt to foods and risk of psoriasis: A prospective cohort study

BACKGROUND

High salt intake may play a critical role in the etiology of psoriasis. Yet, evidence on the association of high salt intake with risk of psoriasis is limited.

OBJECTIVE

To estimate the association between frequency of adding salt to foods and risk of psoriasis.

METHODS

We conducted a prospective cohort study of 433,788 participants from the UK Biobank. Hazard ratios (HRs) and their 95 % confidence intervals (CIs) for risk of psoriasis in relation to frequency of adding salt to foods were estimated using multivariable Cox proportional hazards models. We further evaluated the joint association of adding salt to foods and genetic susceptibility with risk of psoriasis. We conducted a mediation analysis to assess how much of the effect of adding salt to foods on risk of psoriasis was mediated through several selected mediators.

RESULTS

During a median of 14.0 years of follow-up, 4279 incident cases of psoriasis were identified. In the multivariable-adjusted model, a higher frequency of adding salt to foods was significantly associated with an increased risk of psoriasis ("always" versus "never/rarely" adding salt to foods, HR = 1.25, 95 % CI: 1.10, 1.41). The observed positive association was generally similar across subgroups. In the joint association analysis, we observed that participants with a high genetic risk (above the second tertile) and the highest frequency of adding salt to foods experienced 149 % higher risk of psoriasis, when compared with participants with a low genetic risk (below the first tertile) and the lowest frequency of adding salt to foods (HR = 2.49, 95 % CI: 2.05, 3.02). Mediation analysis revealed that 1.8 %-3.2 % of the positive association between frequency of adding salt and risk of psoriasis was statistically significantly mediated by obesity and inflammatory biomarkers such as C-reactive protein and systemic immune-inflammation index (all P values < 0.004).

CONCLUSIONS

Our study demonstrated a positive association between frequency of adding salt to foods and risk of psoriasis. The positive association was independent of multiple other risk factors, and may be partially mediated through obesity and inflammation.

New findings on the risk of hypertension from organophosphorus exposure under different glycemic statuses: The key role of lipids?

BACKGROUND AND OBJECTIVE

Considering the widespread use of organophosphorus pesticides (OPs) and the global prevalence of hypertension (HTN), as well as studies indicating that different glycemic statuses may respond differently to the biological effects of OPs. Therefore, this study, based on the Henan rural cohort, aims to investigate the association between OPs exposure and HTN, and further explores whether lipids mediate these associations.

METHODS

We measured the plasma levels of OPs in 2730 participants under different glycemic statuses using gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). A generalized linear model, Quantile g-computation (QGC), adaptive elastic net (AENET), and Bayesian kernel machine regression (BKMR) models were used to assess the impact of OPs exposure on HTN, with least absolute shrinkage and selection operator (LASSO) penalty regression identifying main OPs. Mediation models were used to evaluate the intermediary role of blood lipids in the OPs-HTN relationship.

RESULTS

The detection rates for all OPs were high, ranging from 76.35 % to 99.17 %. In the normal glucose tolerance (NGT) population, single exposure models indicated that malathion and phenthoate were associated with an increased incidence of HTN (P-FDR < 0.05), with corresponding odds ratios (ORs) and 95 % confidence intervals (CIs) of 1.624 (1.167,2.260) and 1.290 (1.072,1.553), respectively. QGC demonstrated a positive association between OP mixtures and HTN, with malathion and phenthoate being the primary contributors. Additionally, the AENET model's Exposure Response Score (ERS) suggested that the risk of HTN increases with higher ERS (P < 0.001). Furthermore, BKMR revealed that co-exposure to OPs increases HTN risk, with phenthoate having a significant impact. Furthermore, triglycerides (TG) mediated 6.55 % of the association between phenthoate and HTN. However, no association was observed in the impaired fasting glucose (IFG) and type 2 diabetes mellitus (T2DM) populations.

CONCLUSIONS

Our findings suggest that in the NGT population, OPs may significantly contribute to the development of HTN, proposing TG as a potential novel target for HTN prevention.

Gestational diabetes mellitus is associated with greater incidence of dementia during long-term post-partum follow-up

BACKGROUND

The impact of gestational diabetes mellitus (GDM) on incident dementia is unknown. Our aim was to evaluate the relationship between GDM and all-cause dementia and the mediating effects of chronic diseases on this relationship.

METHODS

This prospective cohort study included women from the UK Biobank who were grouped based on GDM history. Multivariate Cox proportional hazard models were used to explore the associations between GDM and dementia. We further analysed the mediating effects of chronic diseases on this relationship and the interactions of covariates.

RESULTS

A total of 1292 women with and 204,171 women without a history of GDM were included. During a median follow-up period of 45 years after first birth, 2921 women were diagnosed with dementia. Women with a GDM history had a 67% increased risk of incident dementia (hazard ratio 1.67, 95% confidence interval: 1.03-2.69) compared with those without a GDM history. According to mediation analyses, type 2 diabetes, coronary heart disease, chronic kidney disease and comorbidities (diagnosed with any two of the three diseases) explained 34.5%, 8.4%, 5.2% and 18.8% of the mediating effect on the relationship. Subgroup analyses revealed that physical activity modified the association between GDM history and dementia (p for interaction = 0.030). Among physically inactive women, GDM was significantly associated with incident dementia; however, this association was not observed among physically active women.

CONCLUSIONS

A history of GDM was associated with a greater risk of incident dementia. Type 2 diabetes partially mediated this relationship. Strategies for dementia prevention might be considered for women with a history of GDM.

Associations of polycyclic aromatic hydrocarbons mixtures with cardiovascular diseases mortality and all-cause mortality and the mediation role of phenotypic ageing: A time-to-event analysis

The associations of polycyclic aromatic hydrocarbons (PAHs) with cardiovascular diseases (CVDs) and all-cause mortality are unclear, especially the joint effects of PAHs exposure. Meanwhile, no studies have examined the effect of phenotypic ageing on the relationship between PAHs and mortality. Therefore, this study aimed to investigate the independent and joint associations between PAHs and CVDs, all-cause mortality, and assess whether phenotypic age acceleration (PhenoAgeAccel) mediate this relationship. We retrospectively collected data of 11,983 adults from the National Health and Nutrition Examination Survey database. Firstly, Cox proportional hazards regression and restricted cubic splines were applied to evaluate the independent association of single PAH on mortality. Further, time-dependent Probit extension of Bayesian Kernel Machine Regression and quantile-based g-computation models were conducted to test the joint effect of PAHs on mortality. Then, difference method was used to calculate the mediation proportion of PhenoAgeAccel in the association between PAHs and mortality. Our results revealed that joint exposure to PAHs showed positive association with CVDs and all-cause mortality. By controlling potential confounders, 1-Hydroxynapthalene (1-NAP) (HR = 1.24, P = 0.035) and 2-Hydroxyfluorene (2-FLU) (HR = 1.25, P < 0.001) showed positive association with CVDs mortality, and they were the top 2 predictors (weight: 0.82 for 1-NAP, 0.14 for 2-FLU) of CVDs mortality. 1-NAP (HR = 1.15, P < 0.001) and 2-FLU (HR = 1.13, P < 0.001) also showed positive association with all-cause mortality, and they were also the top 2 predictors of all-cause mortality (weight: 0.66 for 1-NAP, 0.34 for 2-FLU). PhenoAgeAccel mediated the relationship between 1-NAP, 2-FLU and CVDs, all-cause mortality, with a mediation proportion of 10.00 % to 24.90 % (P < 0.05). Specifically, the components of PhenoAgeAccel including C-reactive protein, lymphocyte percent, white blood cell count, red cell distribution width, and mean cell volume were the main contributors of mediation effects. Our study highlights the hazards of joint exposure of PAHs and the importance of phenotypic ageing on the relationship between PAHs and mortality.

Accelerated aging mediates the associations of unhealthy lifestyles with cardiovascular disease, cancer, and mortality

BACKGROUND

With two well-validated aging measures capturing mortality and morbidity risk, this study examined whether and to what extent aging mediates the associations of unhealthy lifestyles with adverse health outcomes.

METHODS

Data were from 405,944 adults (40-69 years) from UK Biobank (UKB) and 9972 adults (20-84 years) from the US National Health and Nutrition Examination Survey (NHANES). An unhealthy lifestyles score (range: 0-5) was constructed based on five factors (smoking, drinking, physical inactivity, unhealthy body mass index, and unhealthy diet). Two aging measures, Phenotypic Age Acceleration (PhenoAgeAccel) and Biological Age Acceleration (BioAgeAccel) were calculated using nine and seven blood biomarkers, respectively, with a higher value indicating the acceleration of aging. The outcomes included incident cardiovascular disease (CVD), incident cancer, and all-cause mortality in UKB; CVD mortality, cancer mortality, and all-cause mortality in NHANES. A general linear regression model, Cox proportional hazards model, and formal mediation analysis were performed.

RESULTS

The unhealthy lifestyles score was positively associated with PhenoAgeAccel (UKB: β = 0.741; NHANES: β = 0.874, all p < 0.001). We further confirmed the respective associations of PhenoAgeAccel and unhealthy lifestyles with the outcomes in UKB and NHANES. The mediation proportion of PhenoAgeAccel in associations of unhealthy lifestyles with incident CVD, incident cancer, and all-cause mortality were 20.0%, 17.8%, and 26.6% (all p < 0.001) in UKB, respectively. Similar results were found in NHANES. The findings were robust when using another aging measure-BioAgeAccel.

CONCLUSIONS

Accelerated aging partially mediated the associations of lifestyles with CVD, cancer, and mortality in UK and US populations. The findings reveal a novel pathway and the potential of geroprotective programs in mitigating health inequality in late life beyond lifestyle interventions.

Understanding Racial Disparities in Dementia Prevalence Among Veterans

Background

Black and Hispanic older adults have greater incidence of Alzheimer's disease and related dementias relative to White adults, but factors underlying these disparities are not well understood, limiting the ability to address them.

Objective

To determine the impact of demographics, cardiovascular disease (CVD) and risk factors, social determinants of health (SDOH), and neuropsychiatric risk factors on racial/ethnic disparities in dementia risk among Veterans.

Methods

We examined a random sample of 1,579,919 older Veterans (age ≥55) without dementia who received care from the VHA from October 1, 1999 to September 30, 2021. All variables were extracted from national VHA data. We used Cox proportional hazard regression models to examine change in variance in risk of dementia across racial/ethnic groups.

Results

During follow up (mean 11.1 years), 13% of Veterans developed dementia. Relative to White Veterans, the adjusted hazard ratios (AHRs) for developing dementia in sex-adjusted models with age as timescale were 1.65 (95% CI, 1.63-1.67) for Black Veterans and 1.50 (95% CI, 1.44-1.56) for Hispanic Veterans. In the model examining CVD and risk factors, AHRs were 1.53 (95% CI, 1.50-1.55) for Black Veterans and 1.38 (95% CI, 1.33-1.44) for Hispanic Veterans. In the model examining SDOH, AHRs were 1.46 (95% CI, 1.43-1.49) for Black Veterans and 1.34 (95% CI, 1.29-1.40) for Hispanic Veterans.

Conclusions

SDOH and CVD and risk factors accounted for the greatest amount of variance in racial/ethnic disparities in dementia risk. Cardiovascular disease and SDOH are strong possible targets for interventions designed to reduce these disparities.

Relation of Life's Essential 8 to the genetic predisposition for cardiovascular outcomes and all-cause mortality: results from a national prospective cohort

AIMS

To evaluate the independent, mediating, interactive, and associated effects of Life's Essential 8 (LE8) and genetic predisposition on the risk of cardiovascular outcomes and all-cause mortality.

METHODS AND RESULTS

We retrieved a total of 254 783 individuals from the UK Biobank. LE8 was determined by eight metrics (nicotine exposure, physical activity, diet, sleep, body mass index, blood pressure, blood glucose, and blood lipids), and was characterized as low, moderate, and high cardiovascular health (CVH). Genetic predisposition was estimated using the polygenic risk score (PRS). Cox regressions were performed to evaluate the associations between LE8, PRS, and outcomes. During a median follow-up of 12.53 years, all-cause mortality occurred in 10 257 of 197 473 participants, cardiovascular mortality in 2074 of 215 675, and incident cardiovascular disease (CVD) in 71 774 of 215 675. Individuals with moderate or high CVH experienced a lower risk [hazard ratios (HRs) 0.33 to 0.81] of adverse health outcomes compared with their counterparts with low CVH. A substantial proportion (16.1∼69.8%) of health outcomes could be attributable to moderate or high LE8, and up to 51.2% of the associations between PRS and adverse outcomes were mediated by LE8. In high PRS group, individuals with high CVH had lower CVD mortality (HR: 0.26, 95% confidence interval: 0.18, 0.39), compared to those with low CVH.

CONCLUSION

Ideal CVH was associated with lower risks of cardiovascular outcomes and all-cause mortality, with a more pronounced association observed in individuals with high PRS for CVD. Improving CVH according to LE8 guidelines should be encouraged, especially for those with PRS that indicate high CVD risk.

Relationships of Residential Distance to Major Traffic Roads with Dementia Incidence and Brain Structure Measures: Mediation Role of Air Pollution

Background: Uncertainty exists regarding the operating pathways between near-roadway exposure and dementia incidence. We intend to examine relationships between proximity to major roadways with dementia incidence and brain MRI structure measures, and potential mediation roles of air and noise pollution. Methods: The cohort study was based on the UK Biobank. Baseline survey was conducted from 2006 to 2010, with linkage to electronic health records conducted for follow-up. Residential distance to major roadways was ascertained residential address postcode. A land use regression model was applied for estimating traffic-related air pollution at residence. Dementia incidence was ascertained using national administrative databases. Brain MRI measures were derived as image-derived phenotypes, including total brain, white matter, gray matter, and peripheral cortical gray matter. Results: We included 460,901 participants [mean (SD) age: 57.1 (8.1) years; men: 45.7%]. Compared with individuals living >1,000 m from major traffic roads, living ≤1,000 m was associated with a 13% to 14% higher dementia risk, accounting for 10% of dementia cases. Observed association between residential distance and dementia was substantially mediated by traffic-related air pollution, mainly nitrogen dioxide (proportion mediated: 63.6%; 95% CI, 27.0 to 89.2%) and PM2.5 (60.9%, 26.8 to 87.0%). The shorter residential distance was associated with smaller volumes of brain structures, which was also mediated by traffic-related air pollutants. No significant mediation role was observed of noise pollution. Conclusions: The shorter residential distance to major roads was associated with elevated dementia incidence and smaller brain structure volumes, which was mainly mediated by traffic-related air pollution.

Maternal adherence to healthy lifestyle and risk of depressive symptoms in the offspring: mediation by offspring lifestyle

BACKGROUND

Adherence to healthy lifestyles can be beneficial for depression among adults, but the intergenerational impact of maternal healthy lifestyles on offspring depressive symptoms is unknown.

METHODS

In total, 10 368 mothers in Nurses' Health Study II and 13 478 offspring in the Growing Up Today Study were paired. Maternal and offspring healthy lifestyles were defined as a composite score including a healthy diet, normal body mass index (BMI), never-smoking, light-to-moderate consumption of alcohol, and regular moderate-to-vigorous physical activity. Maternal lifestyles were assessed during their offspring's childhood. Offspring depressive symptoms were repeatedly assessed five times using the Center for Epidemiological Studies Depression Scale-10 (CESD-10); the offspring were between the ages of 14 and 30 when the first CESD-10 was assessed. Covariates included maternal variables (age at baseline, race/ethnicity, antidepressant use, pregnancy complications, etc.) and offspring age and sex.

RESULTS

Children of mothers with the healthiest lifestyle had significantly fewer depressive symptoms (a 0.30 lower CESD-10 score, 95% confidence interval (CI) 0.09-0.50) in comparison with children of mothers with the least healthy lifestyle. The association was only found significant in female offspring but not in males. For individual maternal lifestyle factors, a normal BMI, never-smoking, and adherence to regular physical activity were independently associated with fewer depressive symptoms among the offspring. The association between maternal healthy lifestyles and offspring depressive symptoms was mediated by offspring's healthy lifestyles (mediation effect: 53.2%, 95% CI 15.8-87.3).

CONCLUSIONS

Our finding indicates the potential mechanism of intergenerational transmission of healthy lifestyles to reduce the risk of depressive symptoms in offspring.

Trusted residents and housing assistance to decrease violence exposure in New Haven (TRUE HAVEN): a strengths-based and community-driven stepped-wedge intervention to reduce gun violence

BACKGROUND

We describe the rationale and study design for "TRUsted rEsidents and Housing Assistance to decrease Violence Exposure in New Haven (TRUE HAVEN)," a prospective type 1 hybrid effectiveness/implementation study of a multi-level intervention using a stepped wedge design. TRUE HAVEN aims to lower rates of community gun violence by fostering the stability, wealth, and well-being of individuals and families directly impacted by incarceration through the provision of stable housing and by breaking the cycle of trauma.

DESIGN

TRUE HAVEN is an ongoing, multi-level intervention with three primary components: financial education paired with housing support (individual level), trauma-informed counseling (neighborhood level), and policy changes to address structural racism (city/state level). Six neighborhoods with among the highest rates of gun violence in New Haven, Connecticut, will receive the individual and neighborhood level intervention components sequentially beginning at staggered 6-month steps. Residents of these neighborhoods will be eligible to participate in the housing stability and financial education component if they were recently incarcerated or are family members of currently incarcerated people; participants will receive intense financial education and follow-up for six months and be eligible for special down payment and rental assistance programs. In addition, trusted community members and organization leaders within each target neighborhood will participate in trauma-informed care training sessions to then be able to recognize when their peers are suffering from trauma symptoms, to support these affected peers, and to destigmatize accessing professional mental health services and connect them to these services when needed. Finally, a multi-stakeholder coalition will be convened to address policies that act as barriers to housing stability or accessing mental healthcare. Interventions will be delivered through existing partnerships with community-based organizations and networks. The primary outcome is neighborhood rate of incident gun violence. To inform future implementation and optimize the intervention package as the study progresses, we will use the Learn As You Go approach to optimize and assess the effectiveness of the intervention package on the primary study outcome.

DISCUSSION

Results from this protocol will yield novel evidence for whether and how addressing structural racism citywide leads to a reduction in gun violence.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05723614. Registration date: February 01, 2023. Please refer to https://clinicaltrials.gov/ct2/show/NCT05723614 for public and scientific inquiries.

Adverse childhood and adulthood experiences and risk of new-onset cardiovascular disease with consideration of social support: a prospective cohort study

BACKGROUND

The relationship between adverse childhood experiences (ACEs) and adverse adulthood experiences (AAEs) and their association with incident cardiovascular disease (CVD) have not been extensively studied. Considering social support, we evaluated the complex relations of ACEs and AAEs with incident CVD.

METHODS

This prospective cohort study used data from the 2014 life course survey and the 2015 and 2018 surveys of the China Health and Retirement Longitudinal Study, a national survey of Chinese adults aged ≥ 45 years from 28 provinces across China. The study population included 5836 individuals (mean [SD] age, 59.59 [8.22] years, 49.7% were males). Information on ACEs, AAEs, young adulthood social support, health behavior factors, health status factors, and demographics was measured. Cox regression models, the difference method to estimate the mediation proportion, and the additive and multiplicative interactions were performed. Subgroup and sensitivity analyses were also conducted.

RESULTS

During follow-up, 789 incident cases of CVD occurred. The fully adjusted model, including demographics, health behaviors, health status factors (e.g., depressive symptoms), and social support as control variables, demonstrated that the overall number of ACEs (Hazard ratio [HR]: 1.11, 95% CI: 1.08 to 1.14) and AAEs (HR: 1.19, 95% CI: 1.16 to 1.22) were associated with an increased risk of incident CVD. A dose-response relationship existed between the number of ACEs or AAEs and incident CVD risk. The overall AAEs were found to mediate 17.7% (95% CI: 8.2 to 34.2%) of the association between ACEs and incident CVD. Moreover, a significant additive interaction between ACEs and AAEs was detected (RERI [95% CI]: 0.32 [0.09 to 0.56]). Compared with adults without exposure to both ACE and AAE, those with exposure to both at least one ACE and one AAE indicator had the highest risk of incident CVD (HR: 1.96, 95% CI: 1.72 to 2.23).

CONCLUSIONS

Exposure to ACEs or AAEs was independently associated with an increased risk of incident CVD among Chinese middle-aged and older adults in a dose-response manner, and the overall AAEs partially mediated the association between ACEs and incident CVD. Preventive measures aimed at addressing either ACEs or AAEs alone may not significantly reduce the risk of CVD later in life. The necessity of a comprehensive life-course health strategy targeting the prevention of adversity merits increased attention.

Mediation analysis in the presence of continuous exposure measurement error

The difference method is used in mediation analysis to quantify the extent to which a mediator explains the mechanisms underlying the pathway between an exposure and an outcome. In many health science studies, the exposures are almost never measured without error, which can result in biased effect estimates. This article investigates methods for mediation analysis when a continuous exposure is mismeasured. Under a linear exposure measurement error model, we prove that the bias of indirect effect and mediation proportion can go in either direction but the mediation proportion is usually be less biased when the associations between the exposure and its error-prone counterpart are similar with and without adjustment for the mediator. We further propose methods to adjust for exposure measurement error with continuous and binary outcomes. The proposed approaches require a main study/validation study design where in the validation study, data are available for characterizing the relationship between the true exposure and its error-prone counterpart. The proposed approaches are then applied to the Health Professional Follow-up Study, 1986-2016, to investigate the impact of body mass index (BMI) as a mediator for mediating the effect of physical activity on the risk of cardiovascular diseases. Our results reveal that physical activity is significantly associated with a lower risk of cardiovascular disease incidence, and approximately half of the total effect of physical activity is mediated by BMI after accounting for exposure measurement error. Extensive simulation studies are conducted to demonstrate the validity and efficiency of the proposed approaches in finite samples.

Persistence of social isolation and mortality: 10-year follow-up of the Guangzhou Biobank Cohort study

Although social isolation has been associated with higher mortality risk, the associations of persistence of social isolation with mortality are unclear. We investigated the prospective associations of intermittent and persistent social isolation with all-cause and cause-specific mortality, considering the social contact types (face-to-face and non-face-to-face). 30,518 participants were recruited in 2003-2008 initially and 18,104 participants with re-assessed social isolation information in 2008-2012 were followed up to Dec 2019 in Guangzhou Biobank Cohort Study (GBCS). During an average of 9.7 years of follow-up, 2,119 deaths occurred. The isolation at baseline survey, isolation at second survey and persistent isolation were positively associated with all-cause mortality in the minimal adjusted model (adjusted hazard ratio (AHR) =1.24, 95% CI 1.12-1.38, 1.11, 1.00-1.23 and 1.23, 1.05-1.43, respectively). Totally 47.2% of the risk was explained by health status, SEP, and biological, behavioural and psychological factors. Persistent isolation from face-to-face with co-inhabitants, versus no isolation, was associated with higher risks of all-cause (HR=1.40, 1.09-1.81) and CVD (subdistribution hazard ratio (SHR)=1.92, 1.31-2.81) mortality in fully adjusted model. Our study showed that intermittent and persistent isolation were generally associated with higher risks of mortality, and the risks were even higher in those with persistent face-to-face isolation with co-inhabitants.

Reward mediates the association between engagement in noneating activities and state body dissatisfaction: An ecological momentary assessment study

OBJECTIVE

Momentary worsening (i.e., greater than one's average levels) of state body dissatisfaction (BD) has been implicated as a proximal risk factor for eating disorder (ED) behaviors in binge-spectrum EDs. Yet, research exploring the prospective association between noneating activities in daily life (e.g., chores, self-care/coping) and momentary state BD remains limited. Understanding the momentary link between engagement in noneating activities and state BD, and pathways through which engagement in said activities influences momentary state BD is critical to informing treatments. The current ecological momentary assessment (EMA) study examined whether (1) engagement in noneating activities at Time 1 prospectively predicted momentary state BD at Time 2 and (2) reward drawn from noneating activities at Time 1 mediates the prospective association between engagement in noneating activities at Time 1 and momentary state BD at Time 2.

METHOD

Sixty-six adults with transdiagnostic binge eating completed an EMA protocol over 7-14 days. Participants received six EMA signals per day (total EMA observations = 4038). Multilevel modeling was used to examine the research questions.

RESULTS

Engagement in an indoor hobby, outdoor recreation, socializing, and self-care/coping strategies prospectively predicted momentary state BD improvements, while using TV/social media and cooking prospectively predicted momentary state BD worsening. Reward drawn from engagement in these noneating activities mediated the associations.

DISCUSSION

If replicated, these findings suggest that increasing the frequency of certain noneating activities and enhancing their rewarding aspects to improve state BD and decrease ED behavior risk during treatment may be worthy of further exploration.

PUBLIC SIGNIFICANCE

Momentary worsening of state body dissatisfaction (BD) is a risk factor for eating disorder behaviors in individuals with binge eating. This study found that engaging in certain noneating activities (e.g., socializing) prospectively predicted momentary improvements in state BD, while other noneating activities (e.g., cooking) predicted momentary worsening of state BD. Reward drawn from activities mediated these relations. To improve state BD, treatments should target the frequency of, and reward obtained from these noneating activities.

Mediation of Racial and Ethnic Inequities in the Diagnosis of Advanced-Stage Cervical Cancer by Insurance Status

Importance

Black and Hispanic or Latina women are more likely than White women to receive a diagnosis of and to die of cervical cancer. Health insurance coverage is associated with diagnosis at an earlier stage of cervical cancer.

Objective

To evaluate the extent to which racial and ethnic differences in the diagnosis of advanced-stage cervical cancer are mediated by insurance status.

Design, Setting, and Participants

This retrospective, cross-sectional population-based study used data from the Surveillance, Epidemiology, and End Results (SEER) program on an analytic cohort of 23 942 women aged 21 to 64 years who received a diagnosis of cervical cancer between January 1, 2007, and December 31, 2016. Statistical analysis was performed from February 24, 2022, to January 18, 2023.

Exposures

Health inusurance status (private or Medicare insurance vs Medicaid or uninsured).

Main Outcomes and Measures

The primary outcome was a diagnosis of advanced-stage cervical cancer (regional or distant stage). Mediation analyses were performed to assess the proportion of observed racial and ethnic differences in the stage at diagnosis that were mediated by health insurance status.

Results

A total of 23 942 women (median age at diagnosis, 45 years [IQR, 37-54 years]; 12.9% were Black, 24.5% were Hispanic or Latina, and 52.9% were White) were included in the study. A total of 59.4% of the cohort had private or Medicare insurance. Compared with White women, patients of all other racial and ethnic groups had a lower proportion with a diagnosis of early-stage cervical cancer (localized) (American Indian or Alaska Native, 48.7%; Asian or Pacific Islander, 49.9%; Black, 41.7%; Hispanic or Latina, 51.6%; and White, 53.3%). A larger proportion of women with private or Medicare insurance compared with women with Medicaid or uninsured received a diagnosis of an early-stage cancer (57.8% [8082 of 13 964] vs 41.1% [3916 of 9528]). In models adjusting for age, year of diagnosis, histologic type, area-level socioeconomic status, and insurance status, Black women had higher odds of receiving a diagnosis of advanced-stage cervical cancer compared with White women (odds ratio, 1.18 [95% CI, 1.08-1.29]). Health insurance was associated with mediation of more than half (ranging from 51.3% [95% CI, 51.0%-51.6%] for Black women to 55.1% [95% CI, 53.9%-56.3%] for Hispanic or Latina women) the racial and ethnic inequities in the diagnosis of advanced-stage cervical cancer across all racial and ethnic minority groups compared with White women.

Conclusions and Relevance

This cross-sectional study of SEER data suggests that insurance status was a substantial mediator of racial and ethnic inequities in advanced-stage cervical cancer diagnoses. Expanding access to care and improving the quality of services rendered for uninsured patients and those covered by Medicaid may mitigate the known inequities in cervical cancer diagnosis and related outcomes.

Healthy lifestyle, plasma metabolites, and risk of cardiovascular disease among individuals with diabetes

BACKGROUND AND AIMS

Lifestyle management is a fundamental aspect of diabetes care to prevent cardiovascular disease (CVD); however, the underlying metabolic mechanism is not well established. We aimed to identify metabolites associated with different lifestyle factors, and estimate their mediating roles between lifestyle and CVD risk among people with diabetes.

METHODS

Lifestyle and metabolomic data were available for 5072 participants with diabetes who were free of CVD at baseline in the UK Biobank. The healthy level of 5 lifestyle factors was defined as non-central obesity, non-current smoking, moderate alcohol intake, physically active, and healthy diet. A total of 44 biomarkers across 7 metabolic pathways including lipoprotein particles, fatty acids, amino acids, fluid balance, inflammation, ketone bodies, and glycolysis were quantified by nuclear magnetic resonance (NMR) spectroscopy.

RESULTS

All 44 assayed metabolites were significantly associated with at least one lifestyle factor. Approximately half of metabolites, which were mostly lipoprotein particles and fatty acids, showed a mediating effect between at least one lifestyle factor and CVD risk. NMR metabolites jointly mediated 43.4%, 30.0%, 16.8%, 43.4%, and 65.5% of the association of non-central obesity, non-current smoking, moderate alcohol intake, physically active, and healthy diet with lower CVD risk, respectively. In general, though metabolites that significantly associated with lifestyle were mostly different across the 5 lifestyle factors, the pattern of association was consistent between fatty acids and all 5 lifestyle factors. Further, fatty acids showed significant mediating effects in the association between all 5 lifestyle factors and CVD risk with mediation proportion ranging from 12.2% to 26.8%.

CONCLUSIONS

There were large-scale differences in circulating NMR metabolites between individuals with diabetes who adhered to a healthy lifestyle and those did not. Differences in metabolites, especial fatty acids, could partially explain the association between adherence to multiple healthy lifestyle and lower CVD risk among people with diabetes.

Leading mediators of sex differences in the incidence of dementia in community-dwelling adults in the UK Biobank: a retrospective cohort study

BACKGROUND

Little is known regarding whether sex assigned at birth modifies the association between several predictive factors for dementia and the risk of dementia itself.

METHODS

Our retrospective cohort study included 214,670 men and 214,670 women matched by age at baseline from the UK Biobank. Baseline data were collected between 2006 and 2010, and incident dementia was ascertained using hospital inpatient or death records until January 2021. Mediation analysis was tested for 133 individual factors.

RESULTS

Over 5,117,381 person-years of follow-up, 5928 cases of incident all-cause dementia (452 cases of young-onset dementia, 5476 cases of late-onset dementia) were documented. Hazard ratios (95% CI) for all-cause, young-onset, and late-onset dementias associated with the male sex (female as reference) were 1.23 (1.17-1.29), 1.42 (1.18-1.71), and 1.21 (1.15-1.28), respectively. Out of 133 individual factors, the strongest mediators for the association between sex and incident dementia were multimorbidity risk score (percentage explained (95% CI): 62.1% (45.2-76.6%)), apolipoprotein A in the blood (25.5% (15.2-39.4%)), creatinine in urine (24.9% (16.1-36.5%)), low-density lipoprotein cholesterol in the blood (23.2% (16.2-32.1%)), and blood lymphocyte percentage (21.1% (14.5-29.5%)). Health-related conditions (percentage (95% CI) explained: 74.4% (51.3-88.9%)) and biomarkers (83.0% (37.5-97.5%)), but not lifestyle factors combined (30.1% (20.7-41.6%)), fully mediated sex differences in incident dementia. Health-related conditions combined were a stronger mediator for late-onset (75.4% (48.6-90.8%)) than for young-onset dementia (52.3% (25.8-77.6%)), whilst lifestyle factors combined were a stronger mediator for young-onset (42.3% (19.4-69.0%)) than for late-onset dementia (26.7% (17.1-39.2%)).

CONCLUSIONS

Our analysis matched by age has demonstrated that men had a higher risk of all-cause, young-onset, and late-onset dementias than women. This association was fully mediated by health-related conditions or blood/urinary biomarkers and largely mediated by lifestyle factors. Our findings are important for understanding potential mechanisms of sex in dementia risk.

Is the Product Method More Efficient Than the Difference Method for Assessing Mediation?

Mediation analysis is widely used in biomedical research to quantify the extent to which the effect from an exposure on a health outcome is through a mediator and the extent to which the effect is direct. A traditional approach for quantifying mediation is through the difference method. The other popular approach uses a counterfactual framework from which the product method arises. However, there is little prior work to articulate which method is more efficient for estimating 2 key quantities in mediation analysis, the natural indirect effect and mediation proportion. To fill in this gap, we investigated the asymptotic relative efficiency for mediation measure estimators given by the product method and the difference method. We considered 4 data types characterized by continuous and binary mediators and outcomes. Under certain conditions, we show analytically that the product method is equally efficient to the difference method, or more efficient. However, our numerical studies demonstrate that the difference method is usually at least 90% as efficient as the product method under realistic scenarios in epidemiologic research, especially for estimating the mediation proportion. We demonstrate the efficiency results by analyzing the MaxART study (Eswatini, 2014-2017), which aimed to evaluate the effectiveness of the early access to antiretroviral therapy among human immunodeficiency virus-positive patients.

Neighborhood walkability and sex steroid hormone levels in women

BACKGROUND

Neighborhood walkability (NW) has been linked to increased physical activity, which in turn is associated with lower concentrations of sex hormones and higher concentration of SHBG in women. However, no study has directly examined the association of NW with female sex hormone levels.

OBJECTIVE

We conducted a cross-sectional study to evaluate the association between NW and circulating levels of sex hormones and SHBG in pre- and post-menopausal women.

METHODS

We included 797 premenopausal and 618 postmenopausal women from the New York University Women's Health Study (NYUWHS) who were healthy controls in previous nested case-control studies in which sex hormones (androstenedione, testosterone, DHEAS, estradiol and estrone) and SHBG had been measured in serum at enrollment. Baseline residential addresses were geo-coded and the Built Environment and Health Neighborhood Walkability Index (BEH-NWI) was calculated. Generalized Estimating Equations were used to assess the association between BEH-NWI and sex hormone and SHBG concentrations adjusting for individual- and neighborhood-level factors.

RESULTS

In premenopausal women, a one standard deviation (SD) increment in BEH-NWI was associated with a 3.5% (95% CI 0.9%-6.1%) lower DHEAS concentration. In postmenopausal women, a one SD increment in BEH-NWI was related to an 8.5% (95% CI 5.4%-11.5%) lower level of DHEAS, a 3.7% (95% CI 0.5%-6.8%) lower level of testosterone, a 1.8% (95% CI 0.5%-3.0%) lower level of estrone, and a 4.2% (95% CI 2.7%-5.7%) higher level of SHBG. However, the associations with respect to DHEAS and estrone became apparent only after adjusting for neighborhood-level variables. Sensitivity analyses using fixed effects meta-analysis and inverse probability weighting accounting for potential selection bias yielded similar results.

CONCLUSION

Our findings suggest that NW is associated with lower concentrations of androgens and estrone, and increased SHBG, in postmenopausal women, and lower levels of DHEAS in premenopausal women.

Mediation of Healthy Behaviour on the Association of Frailty with Respiratory Diseases Mortality among 0.4 Million Participants: A Prospective Cohort Study from UK Biobank

The mutual relationship between frailty and healthy behaviour and its effect on respiratory diseases mortality remains largely unknown; this study aims to supplement related analysis on it by using a large sample cohort study. We included 411,987 participants from the UK Biobank study (2006-2021), and measured participants' frailty phenotype and healthy behaviour index by using questionnaires and physical measurement. Mortality from respiratory diseases were obtained through linkage to registries. We used the cox proportional hazards model to explore the association of frailty with respiratory diseases mortality, and calculated the mediation proportion of the healthy behaviour. During a median follow-up of 12.48 years, and after adjustment for other covariates and healthy behaviour index, when compared with non-frail participants, being frail was associated with 2.68 times, 3.27 times, and 3.31 times higher risk of total respiratory diseases mortality, influenza and pneumonia mortality and chronic lower respiratory diseases mortality, respectively. The attenuated proportions mediated by healthy behaviour were 5.1% (95% CI: 4.4%, 5.9%), 3.0% (95% CI: 2.1%, 4.2%) and 6.0% (95% CI: 4.9%, 7.4%), respectively. Compared with non-frail individuals with four or five healthy behaviours, frail individuals with no or one healthy behaviour had higher risks of total respiratory diseases mortality (aHR = 4.59; 95% CI: 3.27, 6.45), influenza and pneumonia mortality (aHR = 4.55; 95% CI: 2.30, 9.03), as well as chronic lower respiratory diseases mortality (aHR = 12.70; 95% CI: 5.76, 27.96). Adherence to a healthy lifestyle therefore represents a potentially modifiable target for improving the harmful impact of frailty on reduced life expectancy as a result of respiratory diseases.

Gender differences in work attendance among health care workers in Northern Nigeria during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic has resulted in the overwork of health care workers (HCWs) and greater household burdens for women. This study examines gender differences in HCWs' work attendance under COVID-19 and household burdens as a potential mediator of the gender difference in Northern Nigeria.

METHODS

From April to May 2021, we conducted a cross-sectional survey on work and household burdens with a convenience sample of male and female HCWs (N=334) across 16 facilities in the Gombe, Katsina, and Zamfara states in Northern Nigeria. We used a series of multilevel modified Poisson regression models to examine the associations between gender and HCW work attendance. We also tested the mediation effect of household burdens on this observed association.

FINDINGS

Only 2·10% of HCWs reported <5 days of work in a typical week; 35·33% worked 6-7 days a week (i.e., HCW overwork). Males were more likely than females to report HCW overwork (46·33% vs. 22·93%), and females were more likely than males to report an increase in household burden (59·24% vs. 40·68%). Adjusted regression models found that men were more likely than women to report HCW overwork (ARR: 1·76, 95% CI: 1·17-2·66). Increased household burdens mediated 9 percent of the total effect between gender and HCW work attendance.

INTERPRETATION

The COVID-19 pandemic in Northern Nigeria made female HCWs contend with the dual burdens of formal and informal care work. This contributes to lower attendance among female HCWs and overwork for their male counterparts.

FUNDING

Bill and Melinda Gates Foundation Grant Numbers: OPP1163682 & INV018007.

Combined lifestyle, mental health, and mortality in US cancer survivors: a national cohort study

Background

Adopting healthy lifestyles and staying mentally health are two cost-effective modifiable strategies that cancer survivors can implement in self-management. We aimed to evaluate the independent, mediation, interaction, and joint associations of combined lifestyle and mental health with mortality in cancer survivors.

Methods

We performed a cohort study including 3145 cancer survivors from National Health and Nutrition Examination Survey (2005–2018). A healthy lifestyle score was constructed based on post-diagnosis body mass index, physical activity, diet, smoking, and drinking. Post-diagnosis mental health was assessed by Patient Health Questionnaire (PHQ-9). Hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause, cancer, and non-cancer mortality were computed using Cox proportional hazards regression models.

Results

After 20,900 person-years of follow-up (median, 6.3 years), cancer survivors with higher lifestyle score had decreased mortality, independent of mental health. Compared to participants with lower lifestyle score (0–1), HRs (95% CIs) for all-cause and non-cancer mortality among those with higher lifestyle score (3–5) were 0.68 (0.52–0.89) and 0.69 (0.56–0.85), respectively. 6.2–10.3% of the associations were mediated by mental health. Similar trends were observed among participants categorized by mental health, those with better mental health had lower mortality, independent of lifestyle. Participants with better mental health benefited more from adopting healthy lifestyles, and vice versa. Combinations of higher healthy lifestyle score and better mental health were associated with significant decreased mortality, the lowest mortality was seen in participants with highest healthy lifestyle score and concurrently with best mental health.

Conclusions

For the first time, in this cohort study with a nationally representative sample of US cancer survivors, we comprehensively explored the complex associations of lifestyle, mental health, and mortality. Evidence derived from this study may give much confidence to cancer survivors and healthcare providers that, changing one’s lifestyle and/or staying mentally healthy after cancer diagnosis can improve survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03584-4.

Overall lifestyles and socioeconomic inequity in mortality and life expectancy in China: the China health and nutrition survey

BACKGROUND

socioeconomic inequity in mortality and life expectancy remains inconclusive in low- and middle-income countries, and to what extent the associations are mediated or modified by lifestyles remains debatable.

METHODS

we included 21,133 adults from China Health and Nutrition Survey (1991-2011) and constructed three parameters to reflect participants' overall individual- (synthesising income, education and occupation) and area-level (urbanisation index) socioeconomic status (SES) and lifestyles (counting the number of smoking, physical inactivity and unhealthy diet and bodyweight). HRs for mortality and life expectancy were estimated by time-dependent Cox model and life table method, respectively.

RESULTS

during a median follow-up of 15.2 years, 1,352 deaths were recorded. HRs (95% CIs) for mortality comparing low versus high individual- and area-level SES were 2.38 (1.75-3.24) and 1.84 (1.51-2.24), respectively, corresponding to 5.7 (2.7-8.6) and 5.0 (3.6-6.3) life-year lost at age 50. Lifestyles explained ≤11.5% of socioeconomic disparity in mortality. Higher lifestyle risk scores were associated with higher mortality across all socioeconomic groups. HR (95% CI) for mortality comparing adults with low individual-level SES and 3-4 lifestyle risk factors versus those with high SES and 0-1 lifestyle risk factors was 7.06 (3.47-14.36), corresponding to 19.1 (2.6-35.7) life-year lost at age 50.

CONCLUSION

this is the first nationwide cohort study reporting that disadvantaged SES was associated with higher mortality and shorter life expectancy in China, which was slightly mediated by lifestyles. Risk lifestyles were related to higher mortality across all socioeconomic groups, and those with risk lifestyles and disadvantaged SES had much higher mortality risks.

Smoking During Pregnancy and Risk of Attention-deficit/Hyperactivity Disorder in the Third Generation

BACKGROUND

Animal experiments indicate that environmental factors, such as cigarette smoke, can have multigenerational effects through the germline. However, there are little data on multigenerational effects of smoking in humans. We examined the associations between grandmothers' smoking while pregnant and risk of attention-deficit/hyperactivity disorder (ADHD) in her grandchildren.

METHODS

Our study population included 53,653 Nurses' Health Study II (NHS-II) participants (generation 1 [G1]), their mothers (generation 0 [G0]), and their 120,467 live-born children (generation 2 [G2]). In secondary analyses, we used data from 23,844 mothers of the nurses who were participants in the Nurses' Mothers' Cohort Study (NMCS), a substudy of NHS-II.

RESULTS

The prevalence of G0 smoking during the pregnancy with the G1 nurse was 25%. ADHD was diagnosed in 9,049 (7.5%) of the grandchildren (G2). Grand-maternal smoking during pregnancy was associated with increased odds of ADHD among the grandchildren (adjusted odds ratio [aOR] = 1.2; 95% confidence interval [CI] = 1.1, 1.2), independent of G1 smoking during pregnancy. In the Nurses' Mothers' Cohort Study, odds of ADHD increased with increasing cigarettes smoked per day by the grandmother (1-14 cigarettes: aOR = 1.1; 95% CI = 1.0, 1.2; 15+: aOR = 1.2; 95% CI = 1.0, 1.3), compared with nonsmoking grandmothers.

CONCLUSIONS

Grandmother smoking during pregnancy is associated with an increased risk of ADHD among the grandchildren.

Alcohol intake and total mortality in 142 960 individuals from the MORGAM Project: a population-based study

AIM

To test the association of alcohol consumption with total and cause-specific mortality risk.

DESIGN

Prospective observational multi-centre population-based study.

SETTING

Sixteen cohorts (15 from Europe) in the MOnica Risk, Genetics, Archiving and Monograph (MORGAM) Project.

PARTICIPANTS

A total of 142 960 individuals (mean age 50 ± 13 years, 53.9% men).

MEASUREMENTS

Average alcohol intake by food frequency questionnaire, total and cause-specific mortality.

FINDINGS

In comparison with life-time abstainers, consumption of alcohol less than 10 g/day was associated with an average 11% [95% confidence interval (CI) = 7-14%] reduction in the risk of total mortality, while intake > 20 g/day was associated with a 13% (95% CI = 7-20%) increase in the risk of total mortality. Comparable findings were observed for cardiovascular (CV) deaths. With regard to cancer, drinking up to 10 g/day was not associated with either mortality risk reduction or increase, while alcohol intake > 20 g/day was associated with a 22% (95% CI = 10-35%) increased risk of mortality. The association of alcohol with fatal outcomes was similar in men and women, differed somewhat between countries and was more apparent in individuals preferring wine, suggesting that benefits may not be due to ethanol but other ingredients. Mediation analysis showed that high-density lipoprotein cholesterol explained 2.9 and 18.7% of the association between low alcohol intake and total as well as CV mortality, respectively.

CONCLUSIONS

In comparison with life-time abstainers, consuming less than one drink per day (nadir at 5 g/day) was associated with a reduced risk of total, cardiovascular and other causes mortality, except cancer. Intake of more than two drinks per day was associated with an increased risk of total, cardiovascular and especially cancer mortality.

Estimating the natural indirect effect and the mediation proportion via the product method

Background

The natural indirect effect (NIE) and mediation proportion (MP) are two measures of primary interest in mediation analysis. The standard approach for mediation analysis is through the product method, which involves a model for the outcome conditional on the mediator and exposure and another model describing the exposure–mediator relationship. The purpose of this article is to comprehensively develop and investigate the finite-sample performance of NIE and MP estimators via the product method.

Methods

With four common data types with a continuous/binary outcome and a continuous/binary mediator, we propose closed-form interval estimators for NIE and MP via the theory of multivariate delta method, and evaluate its empirical performance relative to the bootstrap approach. In addition, we have observed that the rare outcome assumption is frequently invoked to approximate the NIE and MP with a binary outcome, although this approximation may lead to non-negligible bias when the outcome is common. We therefore introduce the exact expressions for NIE and MP with a binary outcome without the rare outcome assumption and compare its performance with the approximate estimators.

Results

Simulation studies suggest that the proposed interval estimator provides satisfactory coverage when the sample size ≥500 for the scenarios with a continuous outcome and sample size ≥20,000 and number of cases ≥500 for the scenarios with a binary outcome. In the binary outcome scenarios, the approximate estimators based on the rare outcome assumption worked well when outcome prevalence less than 5% but could lead to substantial bias when the outcome is common; in contrast, the exact estimators always perform well under all outcome prevalences considered.

Conclusions

Under samples sizes commonly encountered in epidemiology and public health research, the proposed interval estimator is valid for constructing confidence interval. For a binary outcome, the exact estimator without the rare outcome assumption is more robust and stable to estimate NIE and MP. An R package mediateP is developed to implement the methods for point and variance estimation discussed in this paper.

Supplementary Information

The online version contains supplementary material available at (10.1186/s12874-021-01425-4).

Changes in adiposity mediate the associations of diet quality with insulin sensitivity and beta-cell function

BACKGROUND AND AIMS

To examine the mediating role of adiposity on the associations of diet quality with longitudinal changes in insulin sensitivity and beta-cell function.

METHODS AND RESULTS

Adults at-risk for type 2 diabetes (T2D) in the PROMISE cohort had 4 assessments over 9 years (n = 442). Alternate Healthy Eating Index (AHEI) scores were used to assess diet quality. Generalized Estimating Equations (GEE) evaluated the associations between the AHEI and longitudinal changes in insulin sensitivity (HOMA2-%S and ISI) and beta-cell function (IGI/HOMA-IR and ISSI-2). The proportion of the mediating effect of waist circumference changes was estimated using the difference method. In the primary longitudinal analysis, AHEI was positively associated with insulin sensitivity and beta-cell function over time (% difference per standard deviation increase of AHEI for HOMA2-%S (β = 11.0, 95%CI 5.43-17.0), ISI (β = 10.4, 95%CI 4.35-16.8), IGI/HOMA-IR (β = 7.12, 95%CI 0.98-13.6) and ISSI-2 (β = 4.38, 95%CI 1.05-7.80), all p < 0.05). There was no significant association between AHEI and dysglycemia incidence (OR = 0.95, 95%CI 0.77-1.17). Adjustments for longitudinal changes in waist circumference substantially attenuated all associations of AHEI with insulin sensitivity and beta-cell function. Mediation analysis indicated that waist circumference mediated 73%, 70%, 83% and 81% of the association between AHEI and HOMA2-%S, ISI, IGI/HOMA-IR, and ISSI-2, respectively (all p < 0.01).

CONCLUSION

In a Canadian population at-risk for T2D, AHEI score was positively associated with changes in insulin sensitivity and beta-cell function. These associations were substantially mediated by waist circumference, suggesting that changes in adiposity may represent an important pathway linking diet quality with risk phenotypes for T2D.

A Metabolomics Analysis of Circulating Carotenoids and Breast Cancer Risk

BACKGROUND

Higher circulating carotenoids are associated with lower breast cancer risk. The underlying biology remains under-explored.

METHODS

We profiled 293 prediagnostic plasma metabolites in a nested case-control study (n = 887 cases) within the Nurses' Health Studies. Associations between circulating carotenoids and metabolites were identified using linear-mixed models (FDR ≤ 0.05), and we further selected metabolites most predictive of carotenoids with LASSO. Metabolic signatures for carotenoids were calculated as weighted sums of LASSO selected metabolites. We further evaluated the metabolic signatures in relation to breast cancer risk using conditional logistic-regression.

RESULTS

We identified 48 to 110 metabolites associated with plasma levels of α-carotene, β-carotene, β-cryptoxanthin, estimated-vitamin-A-potential, lutein/zeaxanthin, and lycopene, which included primarily positively associated metabolites implicated in immune regulation (tryptophan), redox balance (plasmalogens, glutamine), epigenetic regulations (acetylated-/methylated-metabolites), and primarily inversely associated metabolites involved in β-oxidation (carnitines; FDR ≤ 0.05). The metabolomic signatures derived for β-carotene (Q4 vs. Q1 relative risk RR = 0.74, P _trend = 0.02), and estimated-vitamin-A-potential (Q4 vs. Q1 RR = 0.74, P _trend = 0.02)-measured ≥10 years before diagnosis-were associated with lower breast cancer risk. Modest attenuations of RR for measured levels of β-carotene and estimated-vitamin-A-potential were seen when we adjusted for their corresponding metabolic signatures.

CONCLUSIONS

Metabolites involved in immune regulation, redox balance, membrane signaling, and β-oxidation were associated with plasma carotenoids. Although some metabolites may reflect shared common food sources or compartmental colocalization with carotenoids, others may signal the underlying pathways of carotenoids-associated lowered breast cancer risk.

IMPACT

Consumption of carotenoid-rich diet is associated with a wide-range of metabolic changes which may help to reduce breast cancer risk.

The Mediating Role of Placental Weight Change in the Association Between Prenatal Exposure to Thallium and Birth Weight: A Prospective Birth Cohort Study

Background: Previous studies have demonstrated the embryotoxicity and fetotoxicity of thallium (Tl). However, the effects of prenatal exposure to Tl on birth weight and placental weight and the mediating role of placental weight in the association of Tl with birth weight remain unclear.

Methods: We recruited 2,748 participants from the ongoing Prenatal Environment and Offspring Health Cohort (PEOH Cohort) study, which was initiated in 2016 in Guangzhou, China. The Tl concentrations in maternal urine samples collected during the first and third trimester were determined by inductively coupled plasma mass spectrometry. Birth weight and placental weight were extracted from maternal medical records.

Results: Pregnant women exposed to the highest tertile of Tl in the first trimester (β = −42.7 g, 95% CI: −82.3, −3.1 g) and third trimester (β = −50.6 g, 95% CI: −99.0, −2.3 g) had babies with lower birth weights than those exposed to the lowest tertile. We also found significant negative associations of exposure to Tl concentrations in the first and third trimester with placental weight. Mediation analyses showed that 50.3% (95% CI: 15.9, 79.2%) and 33.5% (95% CI: 1.3, 80.3%) of the effects of Tl exposure in the first and third trimester on birth weight were mediated by decreased placental weight.

Conclusion: Our results suggest that prenatal exposure to Tl is negatively associated with birth weight and that this association may be mediated by decreased placental weight.

Neuroticism, negative life events, and dementia in older White and Black Brazilians

OBJECTIVE

Exposure to negative life events (NLEs) and neuroticism are associated with dementia. It is unknown whether neuroticism explains or modifies the association of NLEs with dementia in older Black and White Brazilians.

METHODS

A total of 1747 decedents 65 years and older White and Black (11% Black and 23% Mixed) Brazilians, 53% women, were included in the analyses. Data were obtained in a face-to-face interview with an informant (71% their children) who knew the decedents for 47 years on average. Dementia was classified using the Clinical Dementia Rating. NLEs were assessed with a 10-item scale involving common problems (e.g., death, illness, alcoholism, and financial). Neuroticism was assessed with a 6-item neuroticism scale adapted from the NEO Five-Factor Inventory. Models adjusted for age, sex, and education. Black and mixed-race were combined in the analyses.

RESULTS

NLEs (median of 2) were more common in Blacks than Whites (2.04 vs. 1.82, p = 0.007). More NLEs increased the odds of dementia (OR = 1.112, β = 0.106, p = 0.002), similarly in Blacks and Whites (β interaction  = 0.046, p = 0.526). More NLEs were also associated with higher neuroticism (β = 0.071, p < 0.0001), in Whites but not in Blacks (β interaction  = -0.048, p = 0.006). Neuroticism was associated with higher odds of dementia (OR = 1.658, β = 0.506, p=<0.001), in Whites but not in Blacks (β interaction  = -0.420, p = 0.040). Overall, 34% of the effect of NLEs on dementia was associated with the underlying neuroticism trait in Whites (65%, Indirect OR = 1.060, p < 0.001) but no association was evident in Blacks (6%, Indirect OR = 1.008, p = 0.326). Neuroticism did not moderate the association of NLEs with dementia (OR = 0.979, β = -0.021, p = 0.717).

CONCLUSION

The association of NLEs and dementia is partially explained by neuroticism in older White but not in Blacks Brazilians.

Dietary patterns and risk of developing knee osteoarthritis: data from the osteoarthritis initiative

OBJECTIVE

Some studies have examined the association between dietary factors and risk of knee osteoarthritis (OA). We aimed to examine the prospective association of major dietary patterns with the risk of developing knee OA.

METHOD

We followed 2,842 participants in Osteoarthritis Initiative (OAI) aged 45-79 years and with at least one knee free from radiographic knee OA at baseline for up to 72 months. We defined knee OA incidence as Kellgren and Lawrence grade ≥2 during follow-up visits. Using principal component analysis, Western and prudent dietary patterns were derived. Cox proportional hazards models were used to assess the association between dietary patterns and incident knee OA.

RESULTS

Among study participants, 385 (418 knees) developed knee OA within 72 months. Following a Western dietary pattern was associated with an increased risk of knee OA (HR _{quartile 4 vs 1} = 1.69, 95% CI: 1.13 to 2.52, p trend: 0.03), while adherence to the prudent pattern was associated with a reduced risk of knee OA (HR _{quartile 4 vs 1} = 0.70, 95% CI: 0.50 to 0.98, p trend: 0.05). The observed associations attenuated after additionally adjusting for body mass index (BMI). The observed associations were mediated through BMI by approximately 30%.

CONCLUSION

Following a Western diet was associated with increased risk of knee OA, whereas following a prudent pattern was associated with a reduced risk of knee OA. The associations were partially mediated through BMI.

Body image, physical activity and psychological health in older female cancer survivors

OBJECTIVES

To determine the association of physical activity and body image with psychological health outcomes and whether body image mediates the association of physical activity with psychological health among older female cancer survivors.

MATERIALS AND METHODS

Data from the Women's Health Initiative (WHI) Life and Longevity after Cancer (LILAC) Study were used. Surveys assessed body image (appearance, attractiveness, scars), moderate-strenuous physical activity (min/week), and psychological health (depression, anxiety, distress). A mediation analysis was conducted to estimate the percentage of the total effect of physical activity on psychological health mediated by body image concerns.

RESULTS

Among 4567 female cancer survivors aged 66-98 years, the average time since cancer diagnosis was 9.2 years. Approximately 50% reported no moderate-strenuous physical activity; 15% reported depressive symptoms, 6% reported anxiety, and 5% reported psychological distress; 3% had concerns with appearance, 20% had concerns with attractiveness, and 21% had concerns with scars. When unadjusted for body image concerns, every 30 min/week increase in physical activity was associated with lower risk of depressive symptoms (RR = 0.93, 95%CI: 0.90-0.96), anxiety (RR = 0.92, 95%CI: 0.87-0.97), and distress (RR = 0.92, 95%CI: 0.87-0.98). Body image concerns with appearance mediated 7%, 8.8%, and 14.5% of the association between physical activity and depressive symptoms, anxiety, and distress, respectively.

CONCLUSION

Older female cancer survivors reported body image concerns, which were associated with both physical activity and psychological health. Our findings suggest that interventions designed to address body image concerns in older female cancer survivors could serve to improve the benefit of physical activity on psychological health.

Associations of healthy lifestyle and socioeconomic status with mortality and incident cardiovascular disease: two prospective cohort studies

OBJECTIVE

To examine whether overall lifestyles mediate associations of socioeconomic status (SES) with mortality and incident cardiovascular disease (CVD) and the extent of interaction or joint relations of lifestyles and SES with health outcomes.

DESIGN

Population based cohort study.

SETTING

US National Health and Nutrition Examination Survey (US NHANES, 1988-94 and 1999-2014) and UK Biobank.

PARTICIPANTS

44 462 US adults aged 20 years or older and 399 537 UK adults aged 37-73 years.

EXPOSURES

SES was derived by latent class analysis using family income, occupation or employment status, education level, and health insurance (US NHANES only), and three levels (low, medium, and high) were defined according to item response probabilities. A healthy lifestyle score was constructed using information on never smoking, no heavy alcohol consumption (women ≤1 drink/day; men ≤2 drinks/day; one drink contains 14 g of ethanol in the US and 8 g in the UK), top third of physical activity, and higher dietary quality.

MAIN OUTCOME MEASURES

All cause mortality was the primary outcome in both studies, and CVD mortality and morbidity in UK Biobank, which were obtained through linkage to registries.

RESULTS

US NHANES documented 8906 deaths over a mean follow-up of 11.2 years, and UK Biobank documented 22 309 deaths and 6903 incident CVD cases over a mean follow-up of 8.8-11.0 years. Among adults of low SES, age adjusted risk of death was 22.5 (95% confidence interval 21.7 to 23.3) and 7.4 (7.3 to 7.6) per 1000 person years in US NHANES and UK Biobank, respectively, and age adjusted risk of CVD was 2.5 (2.4 to 2.6) per 1000 person years in UK Biobank. The corresponding risks among adults of high SES were 11.4 (10.6 to 12.1), 3.3 (3.1 to 3.5), and 1.4 (1.3 to 1.5) per 1000 person years. Compared with adults of high SES, those of low SES had higher risks of all cause mortality (hazard ratio 2.13, 95% confidence interval 1.90 to 2.38 in US NHANES; 1.96, 1.87 to 2.06 in UK Biobank), CVD mortality (2.25, 2.00 to 2.53), and incident CVD (1.65, 1.52 to 1.79) in UK Biobank, and the proportions mediated by lifestyle were 12.3% (10.7% to 13.9%), 4.0% (3.5% to 4.4%), 3.0% (2.5% to 3.6%), and 3.7% (3.1% to 4.5%), respectively. No significant interaction was observed between lifestyle and SES in US NHANES, whereas associations between lifestyle and outcomes were stronger among those of low SES in UK Biobank. Compared with adults of high SES and three or four healthy lifestyle factors, those with low SES and no or one healthy lifestyle factor had higher risks of all cause mortality (3.53, 3.01 to 4.14 in US NHANES; 2.65, 2.39 to 2.94 in UK Biobank), CVD mortality (2.65, 2.09 to 3.38), and incident CVD (2.09, 1.78 to 2.46) in UK Biobank.

CONCLUSIONS

Unhealthy lifestyles mediated a small proportion of the socioeconomic inequity in health in both US and UK adults; therefore, healthy lifestyle promotion alone might not substantially reduce the socioeconomic inequity in health, and other measures tackling social determinants of health are warranted. Nevertheless, healthy lifestyles were associated with lower mortality and CVD risk in different SES subgroups, supporting an important role of healthy lifestyles in reducing disease burden.

Association of Daily Alcohol Intake, Volumetric Breast Density, and Breast Cancer Risk

High alcohol intake and breast density increase breast cancer (BC) risk, but their interrelationship is unknown. We examined whether volumetric density modifies and/or mediates the alcohol-BC association. BC cases (n = 2233) diagnosed from 2006 to 2013 in the San Francisco Bay area had screening mammograms 6 or more months before diagnosis; controls (n = 4562) were matched on age, mammogram date, race or ethnicity, facility, and mammography machine. Logistic regression was used to estimate alcohol-BC associations adjusted for age, body mass index, and menopause; interaction terms assessed modification. Percent mediation was quantified as the ratio of log (odds ratios [ORs]) from models with and without density measures. Alcohol consumption was associated with increased BC risk (2-sided P_trend = .004), as were volumetric percent density (OR = 1.45 per SD, 95% confidence interval [CI] = 1.36 to 1.56) and dense volume (OR = 1.30, 95% CI = 1.24 to 1.37). Breast density did not modify the alcohol-BC association (2-sided P > .10 for all). Dense volume mediated 25.0% (95% CI = 5.5% to 44.4%) of the alcohol-BC association (2-sided P = .01), suggesting alcohol may partially increase BC risk by increasing fibroglandular tissue.

Body Composition, Adherence to Anthracycline and Taxane-Based Chemotherapy, and Survival After Nonmetastatic Breast Cancer

Importance

Although most chemotherapies are dosed on body surface area or weight, body composition (ie, the amount and distribution of muscle and adipose tissues) is thought to be associated with chemotherapy tolerance and adherence.

Objectives

To evaluate whether body composition is associated with relative dose intensity (RDI) on anthracycline and taxane-based chemotherapy or hematologic toxic effects and whether lower RDI mediates the association of adiposity with mortality.

Design, Setting, and Participants

An observational cohort study with prospectively collected electronic medical record data was conducted at Kaiser Permanente Northern California, a multicenter, community oncology setting within an integrated health care delivery system. Participants included 1395 patients with nonmetastatic breast cancer diagnosed between January 1, 2005, and December 31, 2013, and treated with anthracycline and taxane-based chemotherapy. Data analysis was performed between February 25 and September 4, 2019.

Exposures

Intramuscular, visceral, and subcutaneous adiposity as well as skeletal muscle were evaluated from clinically acquired computed tomographic scans at diagnosis.

Main Outcomes and Measures

The primary outcome was low RDI (<0.85), which is the ratio of delivered to planned chemotherapy dose, derived from infusion records; in addition, hematologic toxic effects were defined based on laboratory test values. To evaluate associations with overall and breast cancer-specific mortality, logistic regression models adjusted for age and body surface area were fit as well as Cox proportional hazards models adjusted for age, race/ethnicity, adiposity, Charlson comorbidity index score, and tumor stage and subtype. The mediation proportion was computed using the difference method.

Results

The mean (SD) age at diagnosis of the 1395 women included in the study was 52.8 (10.2) years. Greater visceral (odds ratio [OR], 1.19; 95% CI, 1.02-1.39 per SD) and intramuscular (OR, 1.16; 95% CI, 1.01-1.34 per SD) adiposity were associated with increased odds of RDI less than 0.85. Greater muscle mass was associated with a decreased odds of hematologic toxic effects (OR, 0.84; 95% CI, 0.71-0.98 per SD). Relative dose intensity less than 0.85 was associated with a 30% increased risk of death (hazard ratio, 1.30; 95% CI, 1.02-1.65). Lower RDI partially explained the association of adiposity with breast cancer-specific mortality (mediation proportion, 0.20; 95% CI, 0.05-0.55).

Conclusions and Relevance

Excess adiposity, presenting as larger visceral or intramuscular adiposity, was associated with lower RDI. Lower RDI partially mediated the association of adiposity with worse breast cancer-specific survival. Body composition may help to identify patients likely to experience toxic effects and subsequent dose delays or reductions, which could compromise chemotherapeutic efficacy.

Does cartilage loss cause pain in osteoarthritis and if so, how much?

OBJECTIVES

Although treatment development in osteoarthritis (OA) focuses on chondroprotection, it is unclear how much preventing cartilage loss reduces joint pain. It is also unclear how nociceptive tissues may be involved.

METHODS

Using data from the Osteoarthritis Initiative, we quantified the relation between cartilage loss and worsening knee pain after adjusting for bone marrow lesions (BMLs) and synovitis, and examined how much these factors mediated this association. 600 knee MRIs were scored at baseline, 12 months and 24 months for quantitative and semiquantitative measures of OA structural features. We focused on change in medial cartilage thickness using an amount similar to that seen in recent trials. Linear models calculated mean change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score with cartilage loss, adjusted for baseline BMLs, synovitis and covariates. Mediation analysis tested whether change in synovitis or BMLs mediated the cartilage loss-pain association. We carried out a subanalysis for knees with non-zero baseline WOMAC pain scores and another for non-valgus knees.

RESULTS

Cartilage thickness loss was significantly associated with a small degree of worsening in pain over 24 months. For example, a loss of 0.1 mm of cartilage thickness over 2 years was associated with a 0.32 increase in WOMAC pain (scale 0-20). The association of cartilage thickness loss with pain was mediated by synovitis change but not by BML change. Subanalysis results were similar.

CONCLUSIONS

Cartilage thickness loss is associated with only a small amount of worsening knee pain, an association mediated in part by worsening synovitis. Demonstrating that chondroprotection reduces knee pain will be extremely challenging and is perhaps unachievable.

The Association of Cooking Fuel Use, Dietary Intake, and Blood Pressure among Rural Women in China

Household air pollution (HAP) from solid cooking fuels continues to affect 600 million people in China and has been associated with high blood pressure. The role of diet in HAP-associated high blood pressure has yet to be evaluated in China. The aim of this study was to estimate the impact of cooking fuel on change in blood pressure and evaluate whether intake of antioxidant- and omega-3 fatty acid-rich foods (fruits, vegetables, and seafood) attenuates any adverse effects of solid fuel use on blood pressure. We analyzed longitudinal data collected between 1991 and 2011 from nonpregnant women aged 18 to 80 years living in rural areas of China. We used linear mixed effects models to estimate the association between cooking fuel (coal or wood versus clean [electric or liquid petroleum gas]) and blood pressure. Possible mediation of the fuel effect by diet was assessed by the difference method. A total of 6671 women were included in this study. Women less than 40 years of age cooking with cleaner fuels over time had lower rates of change in systolic blood pressure compared to women cooking with coal (p = 0.004), and this effect was not mediated by dietary intake. Associations between fuel use and change in diastolic blood pressure were not significant. These findings lend further support for there being a direct effect of reducing HAP on improvements in blood pressure, independent of concurrent dietary intake.

Evaluation of weight change and hypoglycaemia as mediators in the association between insulin use and death

AIM

To evaluate whether weight change or hypoglycaemia mediates the association between insulin use and death.

MATERIALS AND METHODS

In a retrospective cohort of veterans who filled a new prescription for metformin and added insulin or sulphonylurea (2001-2012), we assessed change in body mass index (BMI) and hypoglycaemia during the first 12 months of treatment intensification. Cox proportional hazards models compared the risk of death between treatment groups. Using the difference method, we estimated the indirect effect and proportion mediated through each mediator. A sensitivity analysis assessed mediators in the first 6 months of intensified therapy.

RESULTS

Among 28 892 patients surviving 12 months, deaths per 1000 person-years were 15.4 for insulin users and 12.9 for sulphonylurea users (HR 1.20, 95% CI 0.87, 1.64). Change in BMI and hypoglycaemia mediated 13% (-98, 98) and -1% (-37, 71) of this association, respectively. Among 30 214 patients surviving 6 months, deaths per 1000 person-years were 34.8 for insulin users and 21.3 for sulphonylurea users (HR 1.66, 95% CI 1.28, 2.15). Change in BMI and hypoglycaemia mediated 9% (1, 23) and 0% (-9, 4) of this association, respectively.

CONCLUSIONS

We observed an increased risk of death among metformin users intensifying treatment with insulin versus sulphonylurea and surviving 6 months of intensified therapy, but not among those surviving 12 months. This association was mediated in part by weight change.

Secondhand smoke, obesity, and risk of type II diabetes among California teachers

PURPOSE

To examine if secondhand smoke (SHS) is associated with elevated risk of type II diabetes among California teachers. We also aim to determine if overall and central obesity are mediators or effect modifiers of this association.

METHODS

Using data from the California Teachers Study, conducted in 1995-2013 in California public schools, we obtained information on SHS exposure among 39,887 lifetime nonsmokers. The association between SHS and incident diabetes after 17 years of follow-up was assessed using Cox regression models. The mediation and modification effects of BMI and waist circumference on this association were tested.

RESULTS

At baseline, 70.2% of the nonsmokers reported exposure to SHS. Higher intensity, duration, and intensity-years of exposure to SHS were associated with higher multivariate adjusted risk of incident diabetes in a dose-response manner (hazard ratio = 1.28; 95% confidence interval, 1.11-1.48 for highest quartile vs. lowest quartile of exposure; P = .001 for trend). Participant's waist circumference (measured 2 years after baseline) could explain greater than 50% of the association between SHS and diabetes.

CONCLUSIONS

SHS exposure is associated with increased risk of type II diabetes among nonsmokers of California teachers with obesity being a potentially important mediator but not an effect modifier for this association.

Sexual-orientation differences in alcohol use trajectories and disorders in emerging adulthood: results from a longitudinal cohort study in the United States

AIMS

We estimated sexual-orientation differences in alcohol use trajectories during emerging adulthood, and tested whether alcohol use trajectories mediated sexual-orientation differences in alcohol use disorders (AUDs).

DESIGN

Longitudinal self-reported survey data from the Growing Up Today Study.

SETTING

United States.

PARTICIPANTS

A total of 12 493 participants aged 18-25 during the 2003, 2005, 2007 or 2010 surveys.

MEASUREMENTS

Stratified by gender, longitudinal latent class analyses estimated alcohol use trajectories (using past-year frequency, quantity and binge drinking from 2003 to 2010). Multinomial logistic regression tested differences in trajectory class memberships by sexual orientation [comparing completely heterosexual (CH) participants with sexual-minority subgroups: mainly heterosexual (MH), bisexual (BI) and gay/lesbian (GL) participants]. Modified Poisson regression and mediation analyses tested whether trajectories explained sexual-orientation differences in AUDs (past-year DSM-IV abuse/dependence in 2010).

FINDINGS

Six alcohol use trajectory classes emerged for women and five for men: these included heavy (23.5/36.9% of women/men), moderate (31.8/26.4% of women/men), escalation to moderately heavy (9.7/12.0% of women/men), light (17.0% for women only), legal (drinking onset at age 21; 11.1/15.7% of women/men) and non-drinkers (7.0/9.1% of women/men). Compared with CH women, MH and BI women had higher odds of being heavy, moderate, escalation to moderately heavy and light drinkers versus non-drinkers (odds ratios = 2.02-3.42; P-values < 0.01-0.04). Compared with CH men, MH men had higher odds of being heavy, moderate and legal drinkers versus non-drinkers (odds ratios = 2.24-3.34; P-values < 0.01-0.01). MH men and women, BI women and GLs had higher risk of AUDs in 2010 than their same-gender CH counterparts (risk ratios = 1.34-2.17; P-values < 0.01). Alcohol use trajectories mediated sexual-orientation differences in AUDs for MH and GL women (proportion of effect mediated = 30.8-31.1%; P-values < 0.01-0.02), but not for men.

CONCLUSIONS

In the United States, throughout emerging adulthood, several sexual-minority subgroups appear to have higher odds of belonging to heavier alcohol use trajectories than completely heterosexuals. These differences partially explained the higher risk of alcohol use disorders among mainly heterosexual and gay/lesbian women but not among sexual-minority men.

Does mammographic density mediate risk factor associations with breast cancer? An analysis by tumor characteristics

BACKGROUND

Though mammographic density (MD) has been proposed as an intermediate marker of breast cancer risk, few studies have examined whether the associations between breast cancer risk factors and risk are mediated by MD, particularly by tumor characteristics.

METHODS

Our study population included 3392 cases (1105 premenopausal) and 8882 (3192 premenopausal) controls from four case-control studies. For established risk factors, we estimated the percent of the total risk factor association with breast cancer that was mediated by percent MD (secondarily, by dense area and non-dense area) for invasive breast cancer as well as for subtypes defined by the estrogen receptor (ER+/ER-), progesterone receptor (PR+/PR-), and HER2 (HER2+/HER2-). Analyses were conducted separately in pre- and postmenopausal women.

RESULTS

Positive associations between prior breast biopsy and risk of invasive breast cancer as well as all subtypes were partially mediated by percent MD in pre- and postmenopausal women (percent mediated = 11-27%, p ≤ 0.02). In postmenopausal women, nulliparity and hormone therapy use were positively associated with invasive, ER+ , PR+ , and HER2- breast cancer; percent MD partially mediated these associations (percent mediated ≥ 31%, p ≤ 0.02). Further, among postmenopausal women, percent MD partially mediated the positive association between later age at first birth and invasive as well as ER+ breast cancer (percent mediated = 16%, p ≤ 0.05).

CONCLUSION

Percent MD partially mediated the associations between breast biopsy, nulliparity, age at first birth, and hormone therapy with risk of breast cancer, particularly among postmenopausal women, suggesting that these risk factors at least partially influence breast cancer risk through changes in breast tissue composition.

Red meat consumption and risk of cardiovascular diseases-is increased iron load a possible link?

Background

High iron load and red meat consumption could increase the risk of cardiovascular diseases (CVDs). As red meat is the main source of heme iron, which is in turn a major determinant of increased iron load, adverse cardiometabolic effects of meat consumption could be mediated by increased iron load.

Objective

The object of the study was to assess whether associations between red meat consumption and CVD risk are mediated by iron load in a population-based human study.

Design

We evaluated relations between red meat consumption, iron load (plasma ferritin), and risk of CVD in the prospective EPIC-Heidelberg Study using a case-cohort sample including a random subcohort (n = 2738) and incident cases of myocardial infarction (MI, n = 555), stroke (n = 513), and CVD mortality (n = 381). Following a 4-step mediation analysis, associations between red meat consumption and iron load, red meat consumption and CVD risk, and iron load and CVD risk were assessed by multivariable regression models before finally testing to which degree associations between red meat consumption and CVD risk were attenuated by adjustment for iron status.

Results

Red meat consumption was significantly positively associated with ferritin concentrations and MI risk [HR per 50 g daily intake: 1.18 (95% CI: 1.05, 1.33)], but no significant associations with stroke risk and CVD mortality were observed. While direct associations between ferritin concentrations and MI risk as well as CVD mortality were significant in age- and sex-adjusted Cox regression models, these associations were substantially attenuated and no longer significant after multivariable adjustment for classical CVD risk factors. Strikingly, ferritin concentrations were positively associated with a majority of classical CVD risk factors (age, male sex, alcohol intake, obesity, inflammation, and lower education).

Conclusion

Increased ferritin concentrations may be a marker of an overall unfavorable risk factor profile rather than a mediator of greater CVD risk due to meat consumption.