Seasonal variation of fluoride intake by children in a subtropical region.

Since the optimum fluoride concentration in drinking water established for temperate countries has been considered not to be appropriate for tropical and subtropical climates, this study was conducted in Piracicaba, a subtropical, optimally fluoridated Brazilian community. The daily fluoride intake by 23 children (aged 20-30 months) from diet (liquids and solids) during the four seasons of the year was evaluated. Duplicate-plate samples of foods and beverages were collected for 2 days in each season of the year. The difference of fluoride intake during the 4 seasons was not statistically significant (p>0.05). However, the adjusted data, based on the volume of the diet collected and on the assumption of a constant fluoride concentration in the drinking water, showed that fluoride intake during spring-summer was statistically higher than that observed during the fall-winter seasons (p<0.05). The fluoride dose to which the children were submitted during the hot seasons would be 19% higher than that found during the cold ones. Although this dose difference would not to be a concern for a subtropical area, it could be relevant for a region with a genuine tropical climate.