Empirical Analysis of the Relationship Between Socioeconomic Status and Dental Caries in Urban Children Across Six Geopolitical Zones in Nigeria

The social gradient of dental caries, where lower socioeconomic status is associated with higher disease burden, is well established globally but has been incompletely characterised across Nigeria's diverse geographic contexts. This study empirically analysed the relationship between socioeconomic status and dental caries in children aged 6 to 12 years across six representative urban centres: Enugu (SE), Lagos (SW), Port Harcourt (SS), Abuja (NC), Kano (NW), and Maiduguri (NE). A multi-site cross-sectional survey was conducted among 2,400 children (400 per site). Dental caries was assessed using DMFT by calibrated dentists. Socioeconomic status was operationalised using a composite index of parental occupation, household monthly income, and residential area type. Multilevel logistic regression was applied to account for site-level clustering. Results showed significant socioeconomic gradients in caries prevalence across all six sites. Children in the lowest SES tertile showed 2.8 times higher caries odds than those in the highest (OR = 2.83, 95% CI: 2.14 to 3.74, p < 0.001). The SES-caries gradient was steepest in Lagos and shallowest in Maiduguri. Access to fluoridated toothpaste was the strongest mediating variable, accounting for 38.2 percent of the gradient. Zone-level variation in sugar consumption patterns modified the gradient strength. The study provides the first multi-zone empirical characterisation of the SES-dental caries gradient in Nigeria and recommends targeted fluoride access equity programmes and sugar marketing restrictions to reduce caries inequality. Keywords: dental caries, socioeconomic status, social gradient, DMFT, multi-site Nigeria