NURSING CARIES, LINEAR HYPOPLASIA, AND NURSING AND WEANING HABITS IN TANZANIAN INFANTS

A cross-sectional survey on the prevalence of rampant caries in infant s and a case-control study were executed to determine the prevalence o f rampant caries and its etiology. A total of 2192 infants aged betwee n 1 and 4.0 yr from nine regions of Tanzania comprised the sample of t he prevalence survey. The overall prevalence of rampant caries resembl ing nursing caries was 6.8%. The prevalence varied considerably betwee n 1.5% and 12.8% in the different regions and was closely associated w ith the varying prevalence of linear hypoplasia but not with fluoride content in drinking water. The relative risk of developing rampant car ies in the presence of linear hypoplasia was 14.5. The case-control st udy comprised 116 cases, infants with rampant caries and 243 controls, without the disorder. Risk factors such as breast feeding frequency a nd duration during day and night, bottle feeding and weaning habits we re assessed through a structured interview with the mother. Bottlefeed ing was performed in only a minority of the infants for a short period (1.1 months) and in a low exposure frequency (0.4 daily) and was not associated with rampant caries. The frequency of sugar moments in the supplementary diet was on average 1.5 times per day and was not associ ated with rampant caries. The duration and frequency of breast feeding during the day was also not associated. The habit of allowing infants to sleep with the breast nipple in their mouths and the presence of l inear hypoplasia were strongly associated with rampant caries. Odds ra tios for these variables were 17.8 and 15.6 respectively. Based on the se associations it is concluded that rampant caries in this sample was caused by the habit of allowing infants to sleep with the breast nipp le in their mouths, whereas linear hypoplasia is considered to be a pr edisposing factor.