The mediating effect of xerostomia in the relationship between psychological factors and oral health-related quality of life among adults in Shanghai, China : Focusing on the moderating effect of oral health care behaviors = 중국 상해 지역 성인의 심리적 요인과 구강건강 관련 삶의 질 간의 관계에서 구강건조증의 매개효과 :구강건강관리행동의 조절효과를 중심으로

다국어 초록 (Multilingual Abstract)

Objective:
This study aimed to investigate the complex relationships among psychological factors (stress, depression, and anxiety), xerostomia symptoms, oral health behaviors, and oral health–related quality of life (OHRQoL) in an adult population in Shanghai. Specifically, we first examined the correlations among these variables, then tested the mediating role of xerostomia symptoms in the association between psychological factors and OHRQoL, and further explored the moderating effect of oral health behaviors on the relationship between xerostomia symptoms and OHRQoL. The
findings are intended to provide empirical evidence for developing integrated oral health strategies that incorporate psychological and behavioral interventions.
Methods:
A cross-sectional survey was conducted in September 2025 using an online questionnaire. A total of 345 permanent residents aged 18–60 years in Shanghai were recruited through a combination of convenience sampling and snowball sampling. Data were collected using a general demographic questionnaire, the Perceived Stress Scale(PSS-10), the Center for Epidemiologic Studies Depression Scale (CES-D), the Generalized Anxiety Disorder Scale (GAD-7), a subjective xerostomia severity scale, an oral health behavior scale, and the Oral Health Impact Profile-14 (OHIP-14). OHRQoL was assessed using the OHIP-14. Statistical analyses were performed with SPSS 27.0 to examine the effects of psychological factors, xerostomia symptoms, and oral health behaviors on OHRQoL.
Results:
(1) Correlation analyses showed that stress, depression, anxiety, and xerostomia symptoms were all significantly negatively correlated with OHRQoL scores, whereas oral health behaviors were significantly positively correlated with OHRQoL (all p < 0.01).(2) Mediation analyses indicated that xerostomia symptoms played a significant partial mediating role in the relationships between psychological factors (stress, depression, and anxiety) and OHRQoL (indirect effect = −0.1215, accounting for 17.77% of the total effect), supporting the pathway of “psychological distress → aggravated xerostomia symptoms → reduced quality of life.”(3) The result of the moderation analysis revealed that oral health behaviors acted as a buffering mechanism for this mediated relation. Indeed, more intensely held beliefs about oral health weakened the adverse relation from symptoms of xerostomia to oral health-related quality of life, and thus people who conduct their daily oral health care more effectively are less influenced by the harmful outcome of xerostomia on their quality of life.
Conclusions:
What has been ascertained from the current research is that there do indeed exist direct links between psychological factors and Oral HealthRelated Quality of Life (OHRQoL), and that within a general community context, the mediating factor that is most vital within this construct is indeed the role of the symptom of xerostomia, while the vital factor that counteracts the negative effect of the symptom of xerostomia on the
aspect of quality of life is regular oral health-related behavior. These findings collectively establish the significance of the intimate association that exists between psychological states and oral health concepts, and further establish the multivariate nature of oral health-related quality of life. Moreover, this research work aims to establish the need for a paradigm shift in the concept of oral health-related quality of life towards the incorporation of a holistic approach based on the concepts of psychological well-being.
Keywords: psychological factors; xerostomia symptoms; oral health behaviors; oral health–related quality of life (OHRQoL)

국문 초록 (Abstract)

연구목적: 본 연구는 상하이 성인 인구를 대상으로 스트레스, 우울, 불안과 같은 심리적 요인과 구강건조 증장, 구강건강행동, 그리고 구강건강관련 삶의 질(Oral Health– Related Quality of Life, OHRQoL) 간의 복합적인 관계를 규명하고자 하였다. 구체적으로는 변수들 간의 상관관계를 분석하고, 심리적 요인과 OHRQoL 의 관계에서 구강건조 증상의 매개효과를 검증하였으며, 더 나아가 구강건강행동이 구강건조 증상과 OHRQoL 간의 관계를 조절하는지를 탐색하였다. 본 연구의 결과는 심리적·행동적 요인을 통합적으로 고려한 구강건강 증진 전략 수립을 위한 경험적 근거를 제공하고자 한다.
연구방법: 2025 년 9 월, 온라인 설문조사를 통해 단면 연구를 실시하였다. 연구는 중국 상하이에 거주하는 만 18세에서 60세 사이의 성인 345명을 대상으로 진행하였다. 조사 도구로는 일반적 특성 설문지, 지각된 스트레스 척도(PSS-10), 역학연구용 우울 척도(CES-D), 범불안장애 척도(GAD-7), 주관적 구강건조 증상 척도, 구강건강행태 척도, 그리고 구강건강관련 삶의 질을 평가하기 위한 OHIP-14 를 사용하였다. 수집된 자료는 SPSS 27.0 을 이용하여 통계 분석을 수행하였다.
연구결과: (1) 상관관계 분석 결과, 스트레스, 우울, 불안 및 구강건조 증상은 모두 OHRQoL 과 유의한 부적 상관관계를 보였으며, 구강건강행동은 OHRQoL 과 유의한 정적 상관관계를 나타냈다(모두 p < 0.01). (2) 매개효과 분석 결과, 구강건조 증상은 심리적 요인(스트레스, 우울, 불안)과 OHRQoL 간의 관계에서 유의한 부분 매개효과를 보였으며(간접효과 = −0.1215, 총효과의 17.77%), 이는 ‘심리적 고통 → 구강건조 증상 악화 → 삶의 질 저하’ 라는 경로를 지지한다. (3) 조절효과 분석에서는 구강건강행동이 구강건조 증상과 OHRQoL 간의 부정적 관계를 완화하는 보호 요인으로 작용함이 확인되었다. 즉, 구강건강에 대한 인식과 실천 수준이 높을수록 구강건조 증상이 삶의 질에 미치는 부정적 영향은 감소하였다.
결론: 본 연구는 심리적 요인이 구강건강관련 삶의 질에 직접적으로 연관되어 있음을 확인하였으며, 지역사회 성인을 대상으로 구강건조 증상이 심리적 고통과 OHRQoL 간의 핵심적인 매개 변수임을 규명하였다. 또한 규칙적이고 효과적인 구강건강행동을 실천하는 것이 구강건조 증상으로 인한 삶의 질 저하를 완충하는 중요한 보호 요인임을 제시하였다. 이러한 결과는 구강건강관련 삶의 질을 심리적 안녕을 포함하는 다차원적 개념으로 재구성할 필요성을 시사하며, 향후 보다 통합적인 구강건강 증진 모델 개발의 이론적 근거를 제공한다.
주제어: 심리적 요인, 스트레스, 불안, 우울, 구강건조 증상, 구강건강행동, 구강건강관련 삶의 질(OHRQoL)

목차 (Table of Contents)

• I INTRODUCTION 4
• 1.THE NECESSITY OF THE STUDY 4
• 2.STUDY AIMS 11
• II. THEORETICAL BACKGROUND 12
• 1. CONCEPTUALIZATION OF PSYCHOLOGICAL FACTORS AND PREVIOUS RESEARCH 26
• a. Stress 26
• b. Depression 27
• c. Anxiety 28
• 2. ORAL HEALTH-RELATED QUALITY OF LIFE 29
• 3. XEROSTOMIA: CONCEPT AND PREVIOUS RESEARCH 30
• 4. ORAL HEALTH CARE BEHAVIORS: CONCEPT AND PREVIOUS RESEARCH 31
• III. RESEARCH CONTENT AND METHODS 33
• 1. RESEARCH MODEL AND HYPOTHESES 33
• a. Hypotheses regarding the relationships between stress, xerostomia, and OHRQoL 33
• b. Hypotheses regarding the relationships between depression, xerostomia, and OHRQoL 34
• c. Hypotheses regarding the relationships between anxiety, xerostomia, and OHRQoL 34
• d. Hypotheses on the Direct Association Between Xerostomia Symptoms and OHRQo 35
• e. Hypotheses on the Direct and Moderating Effects of Oral Health Behaviors 35
• 2. OPERATIONAL DEFINITIONS OF VARIABLES 36
• a. Independent variables 36
• b. Dependent variable 36
• c. Mediator 36
• d. Moderator 37
• 3. QUESTIONNAIRE STRUCTURE 37
• a. Sociodemographic Characteristics 38
• b. Psychological Status Assessment 38
• c. Xerostomia Symptom Assessment 41
• d. Oral Health Care Behaviors 42
• e. Assessment of Oral Health–Related Quality of Life (OHRQoL) 43
• 4. STUDY PARTICIPANTS AND DATA COLLECTION 44
• 5. DATA PROCESSING AND STATISTICAL ANALYSIS 46
• 6. ETHICAL CONSIDERATIONS 48
• IV. RESULTS 49
• 1. CHARACTERISTICS OF THE STUDY PARTICIPANTS 49
• a. Sociodemographic Characteristics of the Participants 49
• b. Oral Health–Related Behaviors and Dental Care Experiences of the Participants 51
• c. Distribution of Scores for Core Study Variables 52
• 2. ANALYSIS OF THE PSYCHOMETRIC PROPERTIES OF THE MEASUREMENT INSTRUMENTS 53
• 3. DIFFERENCES IN CORE VARIABLES ACROSS SOCIODEMOGRAPHIC CHARACTERISTICS AND ORAL HEALTH–RELATED EXPERIENCES 55
• a. Differences in Core Variables by Sociodemographic Characteristics 55
• b. Trends in Oral Health Behaviors and OHRQoL Scores Across Different Oral Health–Related Experiences 57
• 4. CORRELATIONS AMONG KEY VARIABLES 60
• 5. HYPOTHESIS TESTING 61
• a. Mediation analysis of dry mouth symptoms in the relationship between psychological factors(stress, depression, and anxiety) and OHRQoL 61
• b. Validation of mediation effects using Sobel test and bootstrap analysis 66
• c. Moderation analysis of oral health behaviors in the relationship between dry mouth symptoms and OHRQoL 67
• d. Summary of hypothesis testing 69
• V. DISCUSSION 71
• 1. DIRECT NEGATIVE EFFECTS OF PSYCHOLOGICAL FACTORS ON ORAL HEALTH–RELATED QUALITY OF LIFE 72
• 2. THE PARTIAL MEDIATING ROLE OF XEROSTOMIA 74
• 3. THE PROTECTIVE MODERATING ROLE OF ORAL HEALTH BEHAVIORS 77
• 4. STUDY LIMITATIONS AND FUTURE DIRECTIONS 78
• VI. CONCLUSIONS 81
• VII. REFERENCES 83
• ABSTRACT 109
• APPENDIX A 112
• APPENDIX B 122
• ACKNOWLEDGEMENTS 123