The association between oral frailty and HbA1c among older adults with T2DM: the chain mediating effect of nutritional status and physical frailty

Objectives: The present study aimed to explore the association between oral frailty and glycated hemoglobin (HbA1c), and the chain mediating role of nutritional status and physical frailty among older adults with type 2 diabetes mellitus (T2DM).

Methods: Patients with T2DM aged > 60 years were recruited from the endocrinology department of a national metabolic center from October 2023 to March 2024. Oral frailty, nutritional status, and physical frailty were assessed with Oral Frailty Index-8 (OFI-8), the Nutrition Risk Screening 2002 (NRS2002), Fatigue, Resistance, Ambulation, Illness and Loss of Weight Index (FRAIL), respectively. Their HbA1c were collected at the same time. In order to reveal the interaction and influence between multiple variables, chain mediation analyses were conducted using the "Process" macro in SPSS 26.0 to estimate the direct and indirect effects of oral frailty on nutritional status, physical frailty and HbA1c.

Results: A total of 292 participants (50.7% male) were enrolled in this study at a median age of 70.0 (65.2, 76.0) years and a T2DM disease duration of (16.5 ± 9.4) years. After adjustment for age, oral frailty of older people with T2DM significantly positively predicted their HbA1c (β = 0.198, P < 0.001). In addition, oral frailty affect HbA1c through two indirect pathways, including an independent mediating effect of physical frailty (effect = 0.046) and a chain-mediating effect of nutritional status and physical frailty (effect = 0.004).

Conclusions: Our findings suggest that less oral frailty of older adults with T2DM could optimize their nutritional status and physical frailty and, thus, their HbA1c. Consequently, improving oral health is expected to be a promising intervention target for reaching optimal glycaemic control in older adults with T2DM.