Background: Fatigue is a common issue among the elderly with chronic illnesses. This pilot study examined the effects of hemoglobin, age, Sirtuin1 (SIRT1), and rs7069102 on fatigue in older persons with chronic illness.
Methods: A cross-sectional  study of 129 elderly individuals with chronic illnesses was conducted using a moderated mediation analysis. A questionnaire was used to evaluate fatigue, SIRT1 levels were measured using ELISA, and the genotypes of rs7069102 were identified using PCR-CTPP. Hayes’ approach was used in both the mediation and moderated mediation studies.
Results: Hemoglobin levels were negatively correlated with fatigue (r = -0.182, p = 0.038), but age was positively correlated with fatigue (r = 0.183, p = 0.039). The mediation analysis revealed that age had no significant effect on the relationship between hemoglobin level and fatigue. However, moderated mediation analysis indicated a significant indirect effect of the rs7069102 GG genotype on the relationship between hemoglobin, age, and fatigue at all SIRT1 levels (β_(mean-1SD) = -0.100, p = 0.010; β_(mean) = -0.112, p = 0.007; β_(mean+1SD) = -0.122, p = 0.006).
Conclusions: This study shows that the rs7069102 GG genotype at all SIRT1 plasma levels plays as a mediator, reducing the effect of age-related hemoglobin on fatigue. These findings indicate the intricate interaction between genetic factors, physiological parameters, and fatigue perception in these individuals, suggesting for further investigation.