Mediation of Nutritional Status Between the Number of Teeth and Depressive Symptoms in Multi-ethnic Older Adults from Western China

Xin Tian¹Xin Xia²Huixian Li¹Yuexia Hu¹Yuqing Xie¹Xiuying Hu³Jirong Yue²Birong Dong²Bei Wu⁴Yanyan Wang^1*

• ¹West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Healthcare Innovation Research Laboratory, Nursing Key Laboratory of Sichuan Province, National Clinical Research Center for Geriatrics, Chengdu, Sichuan Province, China
• ²West China Hospital, Sichuan University, Department of Geriatrics and National Clinical Research Center for Geriatrics, Chengdu, China
• ³West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Innovation Center of Nursing Research and Nursing Key Laboratory of Sichuan Province, Chengdu, China
• ⁴New York University, Rory Meyers College of Nursing and NYU Aging Incubator, New York, United States

Background: Depression is a prevalent issue among older adults, affecting the quality of life and overall health of individuals. This study aimed to investigate the role of nutritional status in mediating the number of teeth and depressive symptoms.A prospective multi-ethnic baseline data of 6632 adults aged 50 years and older was derived from the 2018 West China Health and Aging Trend study. Depressive symptoms were assessed using the 15-item Geriatric Depression Scale, and nutritional status was evaluated with the Mini Nutritional Assessment-Short Form. A multiple linear regression was performed to assess the associations among the number of teeth, nutritional status, and depressive symptoms. Mediation models and pathway analysis were employed to investigate the mediating role of nutritional status.The sample comprised 18 ethnic groups from western China. The percentage of depressive symptoms among participants was 17.3%. Multiple linear regression indicated a significant correlation between the number of teeth and depressive symptoms. The association remained statistically significant (β = -0.089; 95% CI -0.158, -0.020) after adjusting for MNA-SF scores. Mediation analysis confirmed nutritional status partially mediated the relationship between the number of teeth and depressive symptoms (indirect effect estimate = -0.059; 95% CI -0.076, -0.044, direct effect estimate = -0.089; 95% CI -0.158, -0.020). Furthermore, structural equation model for pathway analysis verified the correlation between the number of teeth, nutritional status, and depressive symptoms (p＜ 0.05).Nutritional status partially mediated the association between the number of teeth and depressive symptoms, revealing significant direct and indirect effects. Early identification of nutritional deficits and the maintenance of oral health are essential for preventing depression in older adults.