Buzalaf M A R, Pessan J P, Alves K M R P
Department of Biological Sciences, Bauru Dental School, University of São Paulo, Bauru, Brazil.
Caries Res. 2006;40(3):231-8. doi: 10.1159/000092231.
This study aimed to determine the lag time between increased fluoride (F) intake and F detection in human nails, as well as the influence of nails growth rate and length on this. Ten 20- to 35-year-old volunteers received 1.8 mg F daily, for 30 days. Nail growth rate and length were determined for all fingernails and toenails. Nail samples were collected at the beginning of the study and every 2 weeks (15 collections in all) and F concentrations were determined. The growth rate was statistically higher in fingernails than in toenails. No statistically significant differences were observed between right and left sides. Growth rate was significantly greater for big toenails than for the other toenails, but this pattern was not found for fingernails. The estimated mean lag times for F detection in fingernails and toenails were 101 and 123 days, respectively. An apparent increase in fingernail F concentrations was observed 84 days after the beginning of the study, although this was not statistically different from baseline. For toenails, statistically significant increases in F concentration in relation to baseline were observed 112 and 140 days after increased F ingestion. These increases occurred within the 95% confidence intervals for the calculated mean lag time for fluoride detection in nails. Considering the large amount of sample provided by the big toenails, together with their faster growth rate, as well as the fact that toenails are less prone to environmental contamination, our data suggest that big toenails are more suitable biomarkers of fluoride intake.
本研究旨在确定人体指甲中氟摄入量增加与氟检测之间的滞后时间，以及指甲生长速率和长度对此的影响。10名年龄在20至35岁之间的志愿者每天摄入1.8毫克氟，持续30天。测定了所有手指甲和脚趾甲的生长速率和长度。在研究开始时以及每2周（共采集15次）采集指甲样本，并测定氟浓度。手指甲的生长速率在统计学上高于脚趾甲。左右两侧未观察到统计学上的显著差异。大脚趾甲的生长速率明显高于其他脚趾甲，但手指甲未发现这种模式。手指甲和脚趾甲中氟检测的估计平均滞后时间分别为101天和123天。在研究开始84天后观察到手指甲氟浓度明显增加，尽管这与基线在统计学上无差异。对于脚趾甲，在氟摄入量增加后112天和140天观察到氟浓度相对于基线有统计学上的显著增加。这些增加发生在计算出的指甲中氟检测平均滞后时间的95%置信区间内。考虑到大脚趾甲提供的样本量大，以及它们的生长速率更快，再加上脚趾甲不易受到环境污染这一事实，我们的数据表明大脚趾甲是更合适的氟摄入量生物标志物。
