title: Fractional urinary fluoride excretion of 6-7-year-old children attending schools in low-fluoride and naturally fluoridated areas in the UK.
abstract: F is an important trace element for bones and teeth. The protective effect of F against dental caries is well established. Urine is the prime vehicle for the excretion of F from the body; however, the relationship between F intake and excretion is complex: the derived fractional urinary F excretion (FUFE) aids understanding of this in different age groups. The present study aimed to investigate the relationships between (1) total daily F intake (TDFI) and daily urinary F excretion (DUFE), and (2) TDFI and FUFE in 6-7-year-olds, recruited in low-F and naturally fluoridated (natural-F) areas in north-east England. TDFI from diet and toothbrushing and DUFE were assessed through F analysis of duplicate dietary plate, toothbrushing expectorate and urine samples using a F-ion-selective electrode. FUFE was calculated as the ratio between DUFE and TDFI. Pearson's correlation and regression analysis were used to investigate the relationship between TDFI and FUFE. A group of thirty-three children completed the study; twenty-one receiving low-F water (0·30 mg F/l) and twelve receiving natural-F water (1·06 mg F/l) at school. The mean TDFI was 0·076 (SD 0·038) and 0·038 (SD 0·027) mg/kg per d for the natural-F and low-F groups, respectively. The mean DUFE was 0·017 (SD 0·007) and 0·012 (SD 0·006) mg/kg per d for the natural-F and low-F groups, respectively. FUFE was lower in the natural-F group (30 %) compared with the low-F group (40 %). Pearson's correlation coefficient for (1) TDFI and DUFE was +0·22 (P= 0·22) and for (2) TDFI and FUFE was − 0·63 (P< 0·001). In conclusion, there was no correlation between TDFI and DUFE. However, there was a statistically significant negative correlation between FUFE and TDFI.
authors.affiliation: School of Health and Social Care, Teesside University, Middlesbrough TS1 3BA, UK. v.zohoori@tees.ac.uk
authors.forename: F V
authors.initials: FV
authors.lastname: Zohoori
authors.forename: R
authors.initials: R
authors.lastname: Walls
authors.forename: L
authors.initials: L
authors.lastname: Teasdale
authors.forename: D
authors.initials: D
authors.lastname: Landes
authors.forename: I N
authors.initials: IN
authors.lastname: Steen
authors.forename: P
authors.initials: P
authors.lastname: Moynihan
authors.forename: N
authors.initials: N
authors.lastname: Omid
authors.forename: A
authors.initials: A
authors.lastname: Maguire
mesh_terms: D002327:Cariostatic Agents / Q000008:administration & dosage; D002648:Child; D003731:Dental Caries / Q000517:prevention & control; D004032:Diet; D002149:Energy Intake; D004739:England; D004781:Environmental Exposure; D005457:Fluoridation; D005459:Fluorides / Q000008:administration & dosage / Q000652:urine*; D009050:Fluorosis, Dental / Q000209:etiology; D054879:Halogenation; D006801:Humans; D012044:Regression Analysis; D012574:Schools; D014099:Toothbrushing; D014131:Trace Elements / Q000008:administration & dosage / Q000652:urine*
chemical_list: D002327:Cariostatic Agents; D014131:Trace Elements; D005459:Fluorides