Oral cancer incidence rate is associated with access to dental care: City and statewide analyses.

INTRODUCTION:Access to dental care may affect diagnosis of oral squamous cell carcinoma (OSCC). We tested whether the incidence rate of OSCC is higher in regions with less dental care access in the city of Chicago and state of Illinois. STUDY DESIGN:Ecological cohort. SETTING:Population, outpatients, and inpatients. METHODS:We extracted 5-year averages of the state-wide county-level and city-level OSCC incidence rates from 2015 to 2019 from the Illinois Department of Public Health. Dental care access information was also collected for each county for the same period, as well as the percentage of people that had ≥1 visit to a dentist in the previous year in Chicago. Multivariate Poisson regression was used to investigate the relationship between county-level access to dental care (and city-level dentist visits) and OSCC incidence rate, controlling for confounders, with additional flexible semiparametric models for confirmatory sensitivity analysis. RESULTS:In Illinois, higher 5-year incidence rate of OSCC was significantly associated with low access to dental care by county (IRR = 0.96, 95% CI 0.91, 0.98). Southern/southwestern counties had higher incidence rates of OSCC (15.5%-28.4%) and the lowest rates of dental care access (47.5%-69.2%) compared to northern counties (10.3%-15% and 55.4%-80.6%, respectively). In Chicago, people with more dentist visits had a reduced chance of being diagnosed with OSCC (IRR = 0.97, 95% CI 0.91, 0.99), consistent with state-wide analyses. CONCLUSION:OSCC incidence rate is closely associated with poor local dental healthcare access in a major state and urban city. Increasing dental access could improve cancer outcomes via improved oral health and earlier detection.