The Relationship between Income and Oral Health: A Critical Review

Abstract

In this critical review, we summarized the evidence on associations between individual/household income and oral health, between income inequality and oral health, and income-related inequalities in oral health. Meta-analyses of mainly cross-sectional studies confirm that low individual/household income is associated with oral cancer (odds ratio, 2.41; 95% confidence interval [CI], 1.59–3.65), dental caries prevalence (prevalence ratio, 1.29; 95% CI, 1.18–1.41), any caries experience (odds ratio, 1.40; 95% CI, 1.19–1.65), tooth loss (odds ratio, 1.66; 95% CI, 1.48–1.86), and traumatic dental injuries (odds ratio, 0.76; 95% CI, 0.65–0.89). Reviews also confirm qualitatively that low income is associated with periodontal disease and poor oral health–related quality of life. Limited evidence from the United States shows that psychosocial and behavioral explanations only partially explain associations between low individual/household income and oral health. Few country-level studies and a handful of subnational studies from the United States, Japan, and Brazil show associations between area-level income inequality and poor oral health. However, this evidence is conflicting given that the association between area-level income inequality and oral health outcomes varies considerably by contexts and by oral health outcomes. Evidence also shows cross-national variations in income-related inequalities in oral health outcomes of self-rated oral health, dental care, oral health–related quality of life, outcomes of dental caries, and outcomes of tooth loss. There is a lack of discussion in oral health literature about limitations of using income as a measure of social position. Future studies on the relationship between income and oral health can benefit substantially from recent theoretical and methodological advancements in social epidemiology that include application of an intersectionality framework, improvements in reporting of inequality, and causal modeling approaches. Theoretically well-informed studies that apply robust epidemiological methods are required to address knowledge gaps for designing relevant policy interventions to reduce income-related inequalities in oral health.

Dental Health and Dental Care Utilization Among Able-Bodied Adults on Medicaid in Kentucky After Medicaid Expansion: A Mixed Methods Study

“…The high prevalence of "fair"/"poor" perceived oral health and low utilization of services among the adult Medicaid expansion population in Kentucky found in this study is consistent with previous studies showing worse oral health outcomes and lower healthcare utilization among low-income individuals (8,22). While beneficiaries have had access to dental benefits since the 2014 expansion, perceived poor health likely reflects chronically poor oral health, which often requires uncovered treatments (i.e., root canals, crowns, and dentures) to replace teeth and recover form and function (23,24).…”

What is intersectionality and why is it important in oral health research?

“…Thereafter, a PubMed search using “intersectionality and oral health” and “intersectionality and dentistry” as keywords on the 30th January 2020 produced only six articles. These six articles included a critical review of income and oral health, which called for an intersectionality approach in its conclusion 33 . A further two papers mentioned intersectionality only in the discussion sections 34,35 .…”

Impact of anterior occlusal conditions in the mixed dentition on oral health–related quality-of-life item levels:

“…In addition, a recent meta-analysis confirmed that low individual/ household income was associated with several adverse oral health outcomes. 30 Thus, the current findings suggested that the socioeconomic condition is still a determining factor in the daily life of an individual, often more than esthetics is.…”