Influence of Fluoridated Groundwater and 1,100 Ppm Fluoride Dentifrice on Biomarkers of Exposure to Fluoride

Abstract This research aimed to determine the influence of fluoridated groundwater and 1,100 ppm fluoride dentifrice on biomarkers of exposure to fluoride in preschoolers. A cross-sectional study was performed on thirty preschoolers recruited from naturally fluoridated and non-fluoridated areas (n=15). Total Daily Fluoride Intake (TDFI) from diet and dentifrice, and Daily Urinary Fluoride Excretion (DUFE) was measured over 24 h. Nails samples were collected twice during 30 days. Fluoride analyses were performed using a fluoride-ion-specific electrode. Data were evaluated using the Student and paired t-test, Pearson correlation analysis, multiple linear regression analysis (α≤0.05). Fluoridated groundwater and dentifrice were the dominant sources (r2 > 0.83) of TDFI in children from a naturally fluoridated and a non-fluoridated area, respectively. A positive correlation between TDFI and DUFE (r=0.50), and between [F] in fingernails and toenails (r=0.60) were found in children from a naturally fluoridated area. The [F] in nails of finger and toe were not correlated to TDFI. The consumption of fluoridated groundwater influenced the fluoride concentration in urine. In addition, the use of 1,100 ppm fluoride dentifrice did not influence the fluoride concentration in urine and fingernails.

摘要
本研究旨在探究含氟地下水与1100ppm氟化物牙膏对学龄前儿童氟暴露生物标志物的影响。本研究采用横断面研究设计，招募了来自天然高氟区与非高氟区的30名学龄前儿童（每组各15名）。研究人员在24小时内采集样本，测定来自膳食与牙膏的每日总氟摄入量（Total Daily Fluoride Intake, TDFI）以及每日尿氟排泄量（Daily Urinary Fluoride Excretion, DUFE）；并在30天内分两次采集指甲样本。氟化物含量检测采用氟离子选择性电极法完成。数据采用Student t检验、配对t检验、Pearson相关分析以及多元线性回归分析进行评估（显著性水平α≤0.05）。
对于来自天然高氟区与非高氟区的儿童，含氟地下水与氟化物牙膏分别为其每日总氟摄入量的主要来源（决定系数r²>0.83）。在天然高氟区儿童中，观察到每日总氟摄入量与每日尿氟排泄量呈正相关（r=0.50），手指甲与脚趾甲中的氟含量亦呈正相关（r=0.60）。但手指与脚趾甲中的氟含量与每日总氟摄入量并无相关性。含氟地下水的摄入会影响尿液中的氟浓度。此外，使用1100ppm氟化物牙膏并不会对尿液与手指甲中的氟浓度产生影响。