Oral-Health related Quality of Life in New Zealand Adults

Abstract

Aims The primary aim of this study was to describe OHRQoL and its associations with sociodemographic characteristics, self-reported experiences and clinical oral disease status among dentate New Zealand adults. The second aim was to identify the nature and extent of oral health inequalities among dentate New Zealand adults.

Methods This study was a secondary analysis of 2009 NZOHS data obtained as a confidential unit record file (CURF) from the Ministry of Health. Overall, 4906 New Zealanders (3475 adults) participated in the survey interview, with 3196 (2209 adults) completing a dental examination. The response rate was 49%. A questionnaire measured self-reported oral health status (including Locker’s global question and the OHIP-14), risk and protective factors for oral health outcomes and the use of oral health care services, among the usually resident New Zealand population living in private dwellings. Analyses used Stata 12 in order to take the complex sampling and weighting into account and yield nationally representative estimates. An OHIP score was computed for each participant (at both subscale and whole-scale level; item weights were not used). Impact prevalence was determined by identifying individuals who reported impacts ‘fairly often’ or ‘very often’. Locker’s global question was used to validate the OHIP-14. After the computation of univariate descriptive statistics, bivariate associations with the dependent variables were tested for statistical significance (using Chi-square tests or ANOVA, as appropriate; the P value was set at 0.05). Impact prevalence was modelled using logistic regression, and the mean OHIP-14 score was modelled using negative binomial regression. The models were repeated for the seven OHIP-14 subscales.

Results The mean OHIP score was 4.1 (3.7, 4.4); impact prevalence was 16.1 % (13.9, 18.5). The OHIP-14 showed consistent gradients across the response categories of Locker’s question. When confounding factors were controlled using multivariate analysis, females, the younger three age groups, Maori, Pacific, those with one or more decayed or missing teeth, severe periodontitis or xerostomia had higher mean OHIP scores. Females, the three younger age groups, the most deprived group, people with one or more decayed or missing teeth, severe periodontitis or xerostomia had higher odds of reporting one or more OHIP impacts ‘fairly often’ or ‘very often’.

Conclusions The oral conditions with the most potential to compromise the OHRQoL of the NZ dentate adult population were decayed and missing teeth, severe periodontitis and xerostomia. Females, the younger three age groups, Māori, and Pacific people experienced poorer OHRQoL than others. From a public health perspective, scarce oral healthcare resources should be targeted at these groups.