Figure 2: COHRA2 study design. Factors impacting infant caries (the outcome variable circled in red) are grouped into (1) environmental risk factors (pink), divided into household and individual risks external to the infant, (2) infant (purple), general health, which will influence infant’s mouth, and (3) mother (blue), general and oral health, which may impact not only mother’s mouth but also infant’s general health and mouth. Mother’s mouth may also directly affect infant’s mouth. Stress may influence either the household or the mother directly. Infant’s mouth is characterized before and after teeth erupt. Data are being collected for every numbered item in each category, as well as measures of stress. EH: enamel hypoplasia.