Please use this identifier to cite or link to this item: https://hdl.handle.net/2440/122294
Type: Thesis
Title: Assessing Nutrition as a Mediator between Oral and General Health
Author: Islam, Saima
Issue Date: 2018
School/Discipline: School of Dentistry
Abstract: Objective: To evaluate the association of oral health on general health and whether food intake mediates the relationship. Method: Data were collected in 2004–06 in a representative sample of Australian adults from NSW and Queensland, using a three-stage, stratified clustered sample, involving a computer-assisted telephone interview (CATI), followed by an oral examination, mailed questionnaire and a food frequency questionnaire (FFQ). Self-rated general health was the outcome, and self-rated oral health, periodontal status, oral health impact (OHIP) and missing-teeth were explanatory variables, and food groups (dairy, bread-cereal, meat-fish-eggs, sweet foods-snacks, mixed-vegetables, vegetables and fruits) were mediators. Age, gender, smoking-status, brushing-habits, diabetes, alcohol-consumption and social-support were the control variables. For mediation analysis Baron and Kenny’s mediation analysis was initially performed, followed by Sobel’s test. Lastly bootstrapping for standard-error and Structural Equation Modelling (SEM) were conducted to assess the consistency of the mediation model. Result: A total of n =14,123 adults responded to the CATI (49% response rate), and n =5505 were examined. In the nutrition sub-study, a total of n = 1218 persons were approached, with n =1129 responding (92.7% response rate). Among them, there were 752 respondents who were aged 45 years or more. From multivariate linear regression analysis, It has been found that adults with better self-rated dental health rated their general health better (β=0.408, p<0.001). Worse oral health was associated with worse general health (for OHIP and missing-teeth, β= -0.027 and -0.01, p<0.001). Adults with none/mild and moderate periodontal problems compared to severe problems rated their general health better (β1=0.13, p<0.001 and β2=0.09, p<0.001). Baron and Kenny, and Sobel tests showed the associations between oral health (OHIP and missing-teeth) were partially mediated by food intake (Sobel test: for all mediators, p<0.001). The associations between periodontal status and self- rated general health were partially mediated by food intake (Sobel test: for all mediators, p<0.05). The association between self-rated dental health and general health was partially mediated by food intake (Sobel test: for all mediators, p<0.01). For all four explanatory variables, periodontitis, number of missing-teeth, OHIP-score and self-rated dental health, Bootstrap results showed zero in the bias-corrected confidence intervals for mediators, indicative of no mediation. SEM analysis for mediation between periodontal status and general health showed p= 0.76, p=0.045, p=0.050, p=0.015, p=0.73, p=0.42 and p= 0.30 for dairy, bread-cereal, meat-fish-eggs, sweet foods-snacks, mixed-vegetables, vegetables and fruits. SEM analysis for mediation showed p= 0.95, p=0.34, p=0.44, p=0.40; p= 0.04 and p=0.58 for dairy, bread-cereal, meat-fish-eggs, sweet foods-snacks, mixed-vegetables, vegetables and fruits respectively for OHIP and p>0.05 for dairy, bread-cereal, meat-fish-eggs, sweet foods-snacks, mixed-vegetables, vegetables and fruits for missing-teeth. SEM analysis for mediation between self-rated dental and general health showed p>0.05 for dairy, bread-cereal, meat-fish-eggs, sweet foods-snacks, mixed-vegetables, vegetables and fruits. Conclusion: SEM indicated the association between periodontitis and self-rated general health was partially mediated by bread-cereal, meat-fish-eggs and sweet-snacks. But the association between self-rated dental health, OHIP-Score or number of missing-teeth and self- rated general health was not mediated by any of these food items.
Advisor: Brennan, David S.
Dissertation Note: Thesis (Ph.D.) -- University of Adelaide, Adelaide Dental School, 2019
Keywords: Oral health
General health
Nutrition, Mediation analysis
Mediation analysis
Structural Equation Modelling (SME)
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals
Appears in Collections:Research Theses

Files in This Item:
File Description SizeFormat 
Islam2018_PhD.pdf6.13 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.