An Original Multivariate Longitudinal Study of Oral Health Determinants and Outcomes Over a Decade in a Nigerian Birth Cohort

Longitudinal birth cohort studies provide the strongest evidence for causal relationships between early life exposures and oral health outcomes, yet no Nigerian dental birth cohort data exist, limiting causal inference about oral health determinants in this population. This study designed, piloted, and reported preliminary findings from the first Nigerian oral health birth cohort study, based on a birth cohort of 840 children in Oyo State (South West) and Kano State (North West) enrolled at birth between 2013 and 2014 and followed annually to 10 years of age. Longitudinal data collected at each annual assessment included DMFT and dmft, oral hygiene indices, dietary assessment, fluoride exposure, socioeconomic measures, and maternal oral health status at baseline. Multivariate mixed-effects models estimated age-specific effects of early life predictors on caries trajectory. At 10-year assessment, cumulative caries experience was significantly higher in the Kano cohort (mean DMFT 3.87) than the Oyo cohort (mean DMFT 2.14, p < 0.001). Birth weight below 2,500 g was significantly associated with higher 10-year caries risk (hazard ratio = 2.41 in survival analysis, p < 0.001). Maternal caries status at enrolment was a significant predictor of child caries by age 5. The Oaxaca decomposition identified fluoride exposure differences as accounting for 41.2 percent of the zone-level caries disparity. The study provides original longitudinal evidence on oral health determinants in Nigerian children and recommends extending the cohort to 18 years with TETFUND longitudinal research funding. Keywords: birth cohort, longitudinal oral health, dental caries determinants, Nigeria, DMFT trajectory