[Fluoride intake and excretion in children of Hermosillo, Sonora, Mexico]

To estimate the fluoride intake and urinary excretion among 8-9 year-old school children.

A cross-sectional study was conducted from February to November 1997. Study subjects were 31 male children from Hermosillo, Mexico, living in three neighborhoods with different drinking water fluoride levels. Fluoride intake was measured through water intake and collection of food samples ingested in 24 hr. Fluoride excretion was measured in 24-hour urine samples. The fluoride concentration was measured by the potentiometer method using a fluoride-specific ion electrode.

Statistically significant differences of fluoride levels in drinking water were found in the 3 different neighborhoods: 2.77, 0.78 and 0.54 mg/L, respectively (p < 0.01). The daily mean intake of fluoride for the neighborhood with the highest fluoride level was 5.41 mg/d, while mean intakes for the other two neighborhoods were 2.31 and 1.51 mg/d, respectively. Thirty-two percent of the children had fluoride intake above the recommendation values for this age group; sixty per cent of these children lived in the neighborhood with the highest fluoride level. Drinking water accounted for 63% of total fluoride intake, and the mean water intake was 1.8 liters. The mean excretion of fluoride was 1.61 mg/24 hours (range 0.18 to 8.1 mg/24 hr). Stepwise multiple regression showed an association between drinking water fluoride and fluoride urinary excretion (R2 = 0.56 p < 0.001).

Fluoride intake in the neighborhood with the highest fluoride level was twice the daily recommended value for 8-9 year-old children. Drinking water was the main source of fluoride intake. The English version of this paper is available at: http://www.insp.mx/salud/index.html.