Is poor self-rated health associated with higher caries experience in adults? The HUNT4 Oral Health Study.

Introduction: The association between lower socioeconomic status and a higher risk of dental caries is well established, but the independent association between general health status and dental caries on a population level is less investigated. The aim of this study was to assess the association between self-rated general health and caries experience in an adult Norwegian population and to assess if the associations were modified by age and sex.

Methods: Data was collected as part of the Trøndelag Health Study (HUNT4) conducted 2017-2019 and a randomly selected subsample (20%) were invited for the HUNT4 Oral Health Study. This cross-sectional study included 4,880 dentate participants aged 19-94 years (response rate 67%). Participants underwent clinical and radiographic oral examinations and caries experience was measured by numbers of decayed (DT), missing (MT), and filled teeth (FT), DMFT index. The DT component consisted of primary and secondary caries in dentine, cavitated root caries and remaining roots. Questionnaires were used to assess self-rated general health and socioeconomic position, denoted by education, household income and employment status. Associations between self-rated health and caries experience (DMFT) and components (DT, MT, and FT) were assessed using negative binomial regression models. Ratios of means (RMs) with 95% confidence intervals (CI) for the associations were estimated, adjusting for socioeconomic position.

Results: Individuals with poor self-rated general health had a 29% higher mean number of MT (RM 1.29 (95%CI 1.13-1.46)), a 22% higher mean number of DT (RM 1.22 (95%CI 1.07-1.39)), and a 7% higher mean number of DMFT (RM 1.07 (95%CI 1.04-1.11)) than individuals reporting very good health. Age stratified analyses presented a more pronounced association between self-rated health and caries experience for individuals below the age of 55 years than for those 55 years or older. Similarly, the association was more evident for women, with significantly higher mean values for DMFT, MT and FT among women reporting poor health.

Conclusions: The present study demonstrated an independent association between poor self-rated health and a higher burden of caries experience, adjusted for education, income and employment status. The association was stronger for women and individuals below the age of 55 years. These findings add new evidence in understanding caries inequalities through self-rated health.