Socioeconomic trajectories across the life course and risk of total and cause-specific mortality: prospective findings from the Moli-sani Study

Life-Course Socioeconomic Trajectories and Biological Aging: The Importance of Lifestyles and Physical Wellbeing

BACKGROUND/OBJECTIVES

Studies investigating the associations between life-course socioeconomic status (SES) and biological aging (the difference between biological and chronological age, Δage) have mostly been focused on epigenetic clocks and on a limited number of mediators. The aim of this study was to investigate this relationship using a blood-based aging clock, as well as the potential mediation of different factors including lifestyles or their proxies and physical and mental wellbeing.

METHODS

A deep-learning aging clock based on 36 blood markers was deployed, in a large Italian population cohort: the Moli-sani study (N = 4772; ≥35 years; 48% men). SES was defined as an eight-level trajectory over the life course, which was tested with Δage in linear models incrementally adjusted for age, sex, and prevalent health conditions. Moreover, the proportion of associations explained by diverse potential mediators, including diet, smoking, physical activity, alcohol, body mass index (BMI), and physical and mental quality of life (QoL) was estimated.

RESULTS

Compared to participants with a stably high SES, those showing an educational and financial downward trajectory were older than their CA (β (95%CI) = 1.28 (0.73-1.83) years), as were those with a stably low SES (0.75 (0.25-01.25) years). These associations were largely explained by the tested mediators (overall proportion: 36.2% and 66.3%, respectively), prominently by physical QoL (20.7% and 41.0%), BMI (16.8% and 34.3%), lifestyle (10.6% and 24.6%), and dietary inflammatory score (5.3% and 9.2%).

CONCLUSIONS

These findings indicate that life-course socioeconomic inequalities are associated with accelerated biological aging, suggesting physical wellbeing and pro-inflammatory lifestyles as potential public health targets to slow down this process in susceptible socioeconomic strata of the population.

Association of perceived mental health with mortality, and analysis of potential pathways in Italian men and women: Prospective results from the Moli-sani Study cohort

BACKGROUND

Perceived mental health (PMH) was reportedly associated with mortality in general populations worldwide. However, little is known about sex differences and pathways potentially linking PMH to mortality. We explored the relationship between PMH and mortality in Italian men and women, and analysed potential explanatory factors.

METHODS

We performed longitudinal analyses on 9045 men and 9467 women (population mean age 53.8 ± 11.2 years) from the Moli-sani Study. Baseline PMH was assessed through a self-administered Short Form 36-item questionnaire. Cox proportional hazard regression was used to estimate hazard ratios (HRs) and 95 % confidence intervals (95%CI) of death across sex-specific quartiles of PMH, controlling for age, chronic health conditions, and perceived physical health. Socioeconomic, behavioural, and physiological factors were examined as potential explanatory factors of the association between PMH and mortality.

RESULTS

In women, HRs for the highest (Q4) vs. bottom quartile (Q1) of PMH were 0.75 (95%CI 0.60-0.96) for all-cause mortality and 0.59 (0.40-0.88) for cardiovascular mortality. Part of these associations (25.8 % and 15.7 %, for all-cause and cardiovascular mortality, respectively) was explained by physiological factors. In men, higher PMH was associated with higher survival (HR = 0.82; 0.69-0.98, for Q4 vs. Q1) and reduced hazard of other cause mortality (HR = 0.67; 0.48-0.95). More than half of the association with all-cause mortality was explained by physiological factors.

LIMITATIONS

PMH was measured at baseline only.

CONCLUSIONS

PMH was independently associated with mortality in men and women. Public health policies aimed at reducing the burden of chronic diseases should prioritize perceived mental health assessment along with other interventions.

Educational Attainment and Lifetime Risk of Cardiovascular Disease

Importance

Education is a social determinant of health. Quantifying its association with lifetime cardiovascular disease (CVD) risk has public health importance.

Objective

To calculate lifetime risk estimates of incident CVD and CVD subtypes and estimate years lived with and without CVD by education.

Design, Setting, and Participants

Included community-based cohort studies with adjudicated cardiovascular events used pooled individual-level data from 1985 to 2015 of 6 prospective cohort studies. The study team assessed the association between education and lifetime CVD risk with modified Kaplan-Meier and Cox models accounting for competing risk of noncardiovascular death. The study team estimated years lived with and without CVD by education with the Irwin restricted mean and the utility of adding educational attainment to CVD risk assessment. Participants (baseline 40 to 59 years old and 60 to 79 years old) were without CVD at baseline and had complete education, cardiovascular risk factors, and prospective CVD outcomes data. Data were analyzed from January 2022 to September 2022.

Exposures

Educational attainment (less than high school, high school completion, some college, or college graduate).

Main outcome and measures

Cardiovascular events (fatal and nonfatal coronary heart disease, heart failure, and stroke; CVD-related deaths; and total CVD encompassing any of these events).

Results

There were 40 998 participants (23 305 female [56.2%]) with a mean (SD) age of 58.1 (9.7) years for males and 58.3 (9.9) years for females. Compared with college graduates, those with less than high school or high school completion had higher lifetime CVD risks. Among middle-aged men, the competing hazard ratios (HRs) for a CVD event were 1.58 (95% CI, 1.38-1.80), 1.30 (95% CI, 1.10-1.46), and 1.16 (95% CI, 1.00-1.34) in those with less than high school, high school, and some college, respectively, compared with those with college completion. Among women, these competing HRs were 1.70 (95% CI, 1.49-1.95), 1.19 (95% CI, 1.05-1.35), and 0.98 (95% CI, 0.83-1.15). Individuals with higher education had longer duration of life prior to incident CVD. Education provided limited contribution toward enhancing CVD risk prediction.

Conclusions and relevance

Lower education was associated with lifetime CVD risk across adulthood; higher education translated to healthy longevity. Educational policy initiatives may associate with long-term health benefits.

Evolution of the income-related gap in health with old age: evidence from 20 countries in European and Chinese panel datasets

Some studies show that the protective effect of higher income on health weakens with old age (age-as-leveller pattern), whereas others show that it strengthens with old age (cumulative advantage/disadvantage pattern). Many existing studies are limited in that they use single-country and/or single-timepoint designs. To overcome these limitations and better understand how the income-health gradient evolves in older age, we used cross-national and longitudinal data of the Survey of Health, Ageing and Retirement in Europe (2004-2019, N = 73,407) and the China Health and Retirement Longitudinal Study (2011-2018, N = 10,067). We operationalised health using multimorbidity and three alternative indicators (functional disability, mobility disability, and memory). We performed Poisson growth curve modelling to capture the between-participant effects of age and the within-participant effects of aging. We obtained three consistent and robust findings for Europe (patterns were observed in most countries) and China. First, the protective effect of higher income on multimorbidity, functional disability, and mobility disability was weaker for older than for younger adults (between-participant age-as-leveller pattern). Second, only the protective effect of higher income on mobility disability weakened over the later life course (within-participant age-as-leveller pattern). Third, the protective effect of higher income on memory was stronger for older than for younger adults and strengthened over the later life course (between-participant and within-participant cumulative advantage/disadvantage pattern). Longitudinal data, growth curve modelling distinguishing the between-participant from within-participant effect, and adjustments for potential confounders based on the hypothesised causal structure enabled us to better navigate the landscape of causal inference. Findings suggest that the income-related gap in physical health but not in cognitive health narrows in old age for both Europe and China.

Short-term socioeconomic status shift and long-term cardiovascular outcomes in China: a population-based cohort study

INTRODUCTION

Limited studies have discussed the effect of socioeconomic status (SES) shift on cardiovascular outcomes, especially in less developed regions and countries. We; therefore, explored the association between short-term SES shift and long-term cardiovascular outcomes in China.

METHODS

In participants who had completed China Kadoorie Biobank study resurvey, 18 672 were included in the final analysis after excluding those who had cardiovascular diseases at baseline, and those who had a cardiovascular event before the resurvey. We used education, occupation, household income and healthcare cover as measurement of SES, and generated SES class for each individual at baseline and resurvey using latent class analysis. Outcomes of interest included cardiovascular death, major coronary event (MCE) and stroke. We used accelerated failure time model to obtain survival time ratio for each level of SES shift.

RESULTS

During a mean time gap of 2.6 years, 10 273 (55%) individuals remained stable in SES, 7763 (41.6%) shifted towards higher SES and 636 (3.4%) shifted towards lower SES. Participants were followed up for a mean of 9.8 years. After adjusting for baseline factors, sharp but not moderate SES downshift was significantly associated with shortened event-free survival time before cardiovascular deaths (p=0.02) and MCEs (p<0.001) occurred. Contrarily, moderate and sharp SES upshift was significantly associated with prolonged event-free survival time before cardiovascular deaths (p=0.0027 and p<0.001) and MCEs (p=0.0079 and p=0.009) occurred.

CONCLUSION

Short-term SES improvement is associated with better long-term cardiovascular outcome in China. High baseline SES might buffer out some unfavourable impact brought by moderate SES downshift. More comprehensive strategies should be considered in policy-making for socioeconomic development.

Exploring domains, clinical implications and environmental associations of a deep learning marker of biological ageing

Deep Neural Networks (DNN) have been recently developed for the estimation of Biological Age (BA), the hypothetical underlying age of an organism, which can differ from its chronological age (CA). Although promising, these population-specific algorithms warrant further characterization and validation, since their biological, clinical and environmental correlates remain largely unexplored. Here, an accurate DNN was trained to compute BA based on 36 circulating biomarkers in an Italian population (N = 23,858; age ≥ 35 years; 51.7% women). This estimate was heavily influenced by markers of metabolic, heart, kidney and liver function. The resulting Δage (BA-CA) significantly predicted mortality and hospitalization risk for all and specific causes. Slowed biological aging (Δage < 0) was associated with higher physical and mental wellbeing, healthy lifestyles (e.g. adherence to Mediterranean diet) and higher socioeconomic status (educational attainment, household income and occupational status), while accelerated aging (Δage > 0) was associated with smoking and obesity. Together, lifestyles and socioeconomic variables explained ~48% of the total variance in Δage, potentially suggesting the existence of a genetic basis. These findings validate blood-based biological aging as a marker of public health in adult Italians and provide a robust body of knowledge on its biological architecture, clinical implications and potential environmental influences.

Life Course Socioeconomic Status and Risk of Hospitalization for Heart Failure or Atrial Fibrillation in The Moli-Sani Study Cohort

We investigated the association of cumulative socioeconomic disadvantage (CSD) and socioeconomic (SES) trajectories across life course with the risk of first hospitalization for heart failure (HF) or atrial fibrillation (AF) and tested some biological mechanisms in explaining such associations. Longitudinal analysis on 21,756 HF- and AF-free subjects recruited in the Moli-sani Study (2005-2010; Italy) and followed up for 8.2 years. CSD was computed using childhood SES, education and adulthood SES indicators, and the same were used to define overall trajectories. High disadvantage across life course (CSD≥8) posed subjects at increased risk of HF (Hazard ratio [HR]=2.58; 95%CI 1.78, 3.74) or AF (HR=1.57;1.05,2.33), as compared to low CSD. All explanatory factors accounted for 18.5% and 24% of the excess of HF and AF risks, respectively, associated with CSD. For subjects with low childhood SES, advancements in education lowered risk of HF (HR=0.70;0.48, 1.02) or AF (HR=0.50;0.28, 0.89), whereas achievements of adulthood SES were unlikely to contribute to disease reduction. In conclusion, a life-course disadvantaged SES is an important predictor of first hospitalization for HF and AF; known risk factors partially explained the SES-disease gradient. Upwardly mobile groups are likely to mitigate the effect of poor childhood circumstances especially through educational advancement.