Social and spatial inequalities in allostatic load among adults in China: a multilevel longitudinal study

Impact of baseline and longitudinal allostatic load changes on incident cardiovascular disease and all-cause mortality: A 7-year population-based cohort study in China

BACKGROUND

We aimed to prospectively examine the association of baseline allostatic load (AL) and longitudinal AL changes with incident cardiovascular disease (CVD) and all-cause mortality among middle-aged and elderly Chinese populations and evaluate the relative contributions of each physiological system of AL.

METHODS

Data from the China Health and Retirement Longitudinal Study (CHARLS) among adults aged 45 years or older were analyzed. Cox regression models were used to estimate the hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) for the associations between baseline AL/longitudinal AL changes with incident CVD and all-cause mortality.

RESULTS

Compared with adults with AL 0-1, HRs of those with baseline AL 2-3 and AL ≥ 4 were 1.24 (95 % CI: 1.06, 1.45) and 1.51 (95 % CI: 1.27, 1.80) for incident CVD, and 1.39 (95 % CI: 1.11, 1.75) and 2.02 (95 % CI: 1.60, 2.54) for all-cause mortality. Similar results were found when we treated baseline AL as a continuous variable. We also found per AL score increase during 4 years of follow-up was related to a 11 % (HR, 1.11; 95 % CI: 1.03, 1.20) and 21 % (HR, 1.21; 95 % CI: 1.10, 1.34) increase in incident CVD and all-cause mortality, respectively.

LIMITATIONS

Self-reported physician-diagnosed CVD was used to assess the incident CVD.

CONCLUSIONS

Both baseline AL and longitudinal increases in AL were positively associated with incident CVD and all-cause mortality in middle-aged and elderly adults. Individuals with high AL need to be dynamically monitored for CVD and pre-mature mortality prevention.

Allostatic Load and Mortality: A Systematic Review and Meta-Analysis

INTRODUCTION

Allostatic load, a measure of stress-related physiologic dysregulation, is associated with numerous mortality risk factors. This systematic review and meta-analysis examines the relationship between high allostatic load (i.e., increased dysregulation versus low dysregulation) and mortality (cardiovascular disease and all-cause mortality).

METHODS

Systematic searches of 2 databases conducted in May 2021 yielded 336 unique records; 17 eligible studies (2001-2020) were included.

RESULTS

High allostatic load was associated with increased risk of all-cause mortality across all the 17 individual studies (hazard ratio=1.08-2.75) and in 6 of 8 studies examining cardiovascular disease mortality (hazard ratio=1.19-3.06). Meta-analyses indicated that high allostatic load was associated with increased risk of all-cause mortality, overall (hazard ratio=1.22, 95% CI=1.14, 1.30, n=10) and across subgroups (hazard ratio=1.11-1.41), and similarly for cardiovascular disease mortality (hazard ratio=1.31, 95% CI=1.10, 1.57, n=6). Although studies were generally of good quality (n=13), heterogeneity was high in most pooled estimates (I²>90%).

DISCUSSION

In this review of relatively good-quality studies, high allostatic load was associated with an increased mortality risk of 22% for all-cause mortality and 31% for cardiovascular disease mortality. Thus, allostatic load is an emerging and potent modifiable risk factor for all-cause and cardiovascular disease mortality that shows promise as a prognostic indicator for mortality. The heterogeneity in allostatic load assessment across studies highlights the need for standardized measurement. The findings underscore the importance of allostatic load's dynamic nature, which may be especially relevant for mitigating mortality risk in younger adults. Because older adults are oversampled, future allostatic load research should prioritize younger adults and longitudinal monitoring and specific cardiovascular disease mortality risk associations and individualize behavioral and lifestyle targets for reducing allostatic load.

Allostatic Load and Its Impact on Health: A Systematic Review

INTRODUCTION

Allostatic load refers to the cumulative burden of chronic stress and life events. It involves the interaction of different physiological systems at varying degrees of activity. When environmental challenges exceed the individual ability to cope, then allostatic overload ensues. Allostatic load is identified by the use of biomarkers and clinical criteria.

OBJECTIVE

To summarize the current knowledge on allostatic load and overload and its clinical implications based on a systematic review of the literature.

METHODS

PubMed, PsycINFO, Web of Science, and the Cochrane Library were searched from inception to December 2019. A manual search of the literature was also performed, and reference lists of the retrieved articles were examined.We considered only studies in which allostatic load or overload were adequately described and assessed in either clinical or non-clinical adult populations.

RESULTS

A total of 267 original investigations were included. They encompassed general population studies, as well as clinical studies on consequences of allostatic load/overload on both physical and mental health across a variety of settings.

CONCLUSIONS

The findings indicate that allostatic load and overload are associated with poorer health outcomes. Assessment of allostatic load provides support to the understanding of psychosocial determinants of health and lifestyle medicine. An integrated approach that includes both biological markers and clinimetric criteria is recommended.