Exploring the moderating effects of SIRT1 protein expression and gene polymorphisms rs7895833 on the relationship between hemoglobin levels and physical frailty in elderly adults with comorbid chronic diseases: A moderated mediation analysis

Abstract

Background: Relationship age, hemoglobin, and physical frailty have all been investigated in older people with more than one chronic disease. There has been little analysis of the relationship between hemoglobin, age, physical frailty, Sirtuin1 (SIRT1) protein expression, and the gene polymorphism (SNP) rs7895833 A>G. The goal of this study was to find out how SIRT1 level, SNP rs7895833, hemoglobin, age, and physical frailty (frail score) are related in older Indonesian adults with comorbid chronic diseases. Methods: This was an observational study. Demographic and clinical data were retrieved from the electronic health records of Universitas Sumatera Utara Hospital, Medan, Indonesia. Physical frailty, SIRT1 level, and SNP rs7895833 were measured using an appropriate and valid method. Purposive sampling was used to determine the eligibility of 132 elderly adults from November 2022 to February 2023. Results: The indirect effect of hemoglobin on the frail score (FS) through age was negative and significant, according to a conditional mediation analysis (β=-0.0731; p=0.023). Meanwhile, the direct effect of hemoglobin on the FS was negative and not significant (β=0.1632; p=0.052). According to the conditional moderated mediation analysis, the size of the direct effect of age on FS was increased by genotype AG-GG and SIRT1 level (βlow=0.2647; p=0.002, βmiddle=0.2956; p<0.001, and βhigh=0.319; p<0.001). The size of the conditional indirect effect of Hemoglobin on FS through age was negative and significantly increased by SNP genotype AG-GG and SIRT1 level (βlow=-0.0647; p=0.032, βmiddle=-0.0723; p=0.024, and βhigh=-0.078; p=0.02). Conclusions: Hemoglobin levels in the blood decrease with age, which might affect elderly people who also have chronic diseases. Higher levels of SIRT1 and the SNP genotype AG-GG can both contribute to this. However, the interactions between these variables are complex, necessitating more research to fully comprehend the mechanisms underlying the development of physical frailty in the aging population.