The Protective Effect of Breastfeeding on Dental Fluorosis Among Children in Rural Fluoride-Endemic Areas.

Living in fluoride-endemic areas and the inevitable use of groundwater for consumption have imposed children at high risk of dental fluorosis. To mitigate exposure to excessive fluoride at age of developing dentition, breastfeeding might serve as a natural public health intervention against dental fluorosis in that socially disadvantaged context. This study aimed to evaluate the preventive effect of breastfeeding against dental fluorosis in children living in fluoride-endemic areas in Nakhon Pathom Province, Thailand. Evaluation of the association through several epidemiological models depicted by a directed acyclic graph (DAG) was undertaken. A case-control study of 127 cases of dental fluorosis and 85 controls was conducted. Independent factor of breastfeeding, along with other past exposure variables, were traced backwardly since infancy by caregiver history taking. Fluoride concentrations in groundwater utilized for household supply matching to residence and number of years by age of each child were collected from 2008 to 2015. Multivariable Poisson regression with robust standard errors was sequentially executed to estimate prevalence ratio (PR) according to models in DAG. Breastfeeding was significantly higher (95.3%) among controls compared to cases (84.2%),  = 0.014. Contrastingly, prevalence of using toothpaste larger than pea-sized and having fluoride ≥1.5 ppm in household water supply was higher among cases. Univariable and subsequent five multivariable regression models according to DAG consistently unveiled significant protective effect of breastfeeding on dental fluorosis with PR ranging from 0.66 to 0.75. Breastfeeding for at least 6 months had preventive effect against dental fluorosis among children living in fluoride-endemic areas.