New study finds mental health is key to healthy aging

A recent study published in the journal Nature Human ActionThe researchers assessed the causal influence of mental health on a genetically independent aging phenotype (aging GIP).

Although human life expectancy has increased over time, the aging of the population poses challenges for individuals and society. Mental health is correlated with lifestyle behaviors and morbidity. Studies have shown that mental health is related to better physical health and survival. Additionally, socioeconomic status (SES) is correlated with aging and mental health. However, the causal relationship between healthy aging and mental health has yet to be established.

study: Evidence for a causal effect of mental health on healthy aging through Mendelian randomizationImage credit: Darren Baker / Shutterstock

About the Research

In this study, the researchers evaluated the impact of mental health on aging phenotypes. This Mendelian randomization (MR) study assessed the causal relationship between aging phenotypes and mental health traits and screened candidate mediators in the relationship between aging GIP and health spectrum. In addition, the research team also explored whether the causal effect was independent of SES.

Summary-level genome-wide association study (GWAS) data were obtained from individuals of European descent. Exposures included happiness spectrum, life satisfaction, neuroticism, depressive symptoms, and positive affect. Covariates were three SES indicators: education, occupation, and income. Overall, 106 candidate mediators were identified for screening. Mediators included 23 lifestyle factors, 20 physical functioning traits, 53 diseases, and 10 behaviors and performances.

The mediator was selected based on a set of criteria: The mediator must be causally related to the aging GIP and have a direct causal effect independent of the well-being spectrum; the well-being spectrum must be causally related to the mediator (and not vice versa); the association between the mediator and the aging GIP and the association between the well-being spectrum and the mediator must be in the same direction.

Outcomes included the ageing GIP and its components (self-rated health, resilience, lifespan, healthy lifespan, and parental lifespan). Linkage disequilibrium score regression analyses were performed to examine genetic correlations between mental health traits, ageing phenotypes, and SES indicators. Univariate MR (UVMR) analyses assessed the causal effects of mediators and mental health traits on ageing phenotypes.

UVMR and multivariate MR (MVMR) analyses were conducted to investigate the causal effect of SES indicators on psychological well-being traits. MVMR analyses adjusted for SES indicators examined the direct effect of well-being spectrum on aging phenotypes. Two-stage MR analyses tested the mediation effect between well-being spectrum and aging GIP.

Investigation result

Genetic correlations were found between all psychological well-being traits, except longevity, and the age-related GIP and its components. The well-being spectrum was associated with increased age-related GIP. Consistently, the well-being spectrum showed positive causal associations with resilience, healthspan, parental longevity, and self-rated health.

Positive affect and life satisfaction were positively correlated with these aging phenotypes, whereas depressive symptoms and neuroticism were inversely correlated. SES indicators and well-being traits were also correlated. Higher income, higher education, and higher occupation were causally associated with improved psychological well-being. Happiness range was independently correlated with higher elderly GIP adjusted for SES indicators.

Of 106 candidate mediators, 33 met the screening criteria and were included. Unhealthy lifestyle factors, physical function, behavior, and performance were associated with lower age-related GIP. Later age at smoking initiation, cheese consumption, appendicular lean mass (ALM), cognitive performance, high-density lipoprotein cholesterol (HDL-C), and higher fresh fruit intake were associated with higher age-related GIP.

Heart failure, hypertension, stroke, and coronary heart disease had the greatest influence on aging GIP. Antihypertensive drugs, age at smoking initiation, and television viewing time independently mediated at least 7% of the effect of the well-being spectrum on aging GIP. Nonsteroidal anti-inflammatory drugs, waist-to-hip ratio, fresh fruit intake, ALM, HDL-C, triglycerides, and age at menarche each mediated up to 4.81% of the total effect.

Conclusion

In summary, this study revealed a causal effect of mental health on aging phenotypes, independent of SES. Better mental health was associated with improved aging GIP. The causal effect was partially explained by 33 mediating factors, including lifestyle, physical function, disease, behavior, and performance. Overall, the results highlight the need to prioritize mental health for healthy aging.