Background

Early-life renal maturation is susceptible to nephrotoxic environmental chemicals. Given the widespread consumption of fluoride and the global obesity epidemic, our main aim was to determine whether childhood fluoride exposure adversely affects kidney function in preadolescence, and if adiposity status modifies this association.

Methods

Our study included 438 children from the PROGRESS cohort. Urinary fluoride (uF) was assessed at age 4 by diffusion analysis; outcomes studied included estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), selected kidney proteins and blood pressure measured at age 8–12 years. We modeled the relationship between uF and outcomes, and adjusted for body mass index (BMI), age, sex, and socioeconomic status.

Results

The median uF concentration was 0.67 μg/mL. We observed null associations between 4-year uF and preadolescent eGFR, although effect estimates were in the expected inverse direction. A single unit increase in ln-transformed uF was associated with a 2.2 mL/min decrease in cystatin C-based eGFR (95% CI: 5.8, 1.4; p = 0.23). We observed no evidence of sex-specific effects or effect modification by BMI status. Although uF was not associated with BMI, among children with obesity, we observed an inverse association (β: 4.8; 95% CI: 10.2, 0.6; p = 0.08) between uF and eGFR.

Conclusions

Low-level fluoride exposure in early childhood was not associated with renal function in preadolescence. However, given the adverse outcomes of chronic fluoride consumption it is possible that the preadolescent age was too young to observe any effects. Longitudinal follow-up in this cohort and others is an important next step.

中文翻译：

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儿童早期氟化物暴露和青春期前肾功能

背景

早期肾脏成熟对肾毒性环境化学物质敏感。鉴于氟化物的广泛消费和全球肥胖流行，我们的主要目的是确定儿童氟化物暴露是否会对青春期前的肾功能产生不利影响，以及肥胖状况是否会改变这种关联。

方法

我们的研究包括来自 PROGRESS 队列的 438 名儿童。在 4 岁时通过扩散分析评估尿氟化物 (uF)；研究的结果包括估计的肾小球滤过率 (eGFR)、血尿素氮 (BUN)、选定的肾脏蛋白和在 8-12 岁时测量的血压。我们模拟了 uF 和结果之间的关系，并根据体重指数 (BMI)、年龄、性别和社会经济地位进行了调整。

结果

中值 uF 浓度为 0.67 μg/mL。我们观察到 4 年 uF 和青春期前 eGFR 之间的无效关联，尽管效果估计与预期的相反方向。ln 转化的 uF 增加一个单位与基于胱抑素 C 的 eGFR 降低 2.2 mL/min 相关（95% CI：5.8，1.4；p = 0.23）。我们没有观察到 BMI 状态存在性别特异性效应或效应改变的证据。尽管 uF 与 BMI 无关，但在肥胖儿童中，我们观察到 uF 和 eGFR 之间存在负相关（β：4.8；95% CI：10.2, 0.6；p = 0.08）。

结论

儿童早期的低水平氟化物暴露与青春期前的肾功能无关。然而，鉴于长期摄入氟化物的不良后果，青春期前的年龄可能太小而无法观察到任何影响。该队列和其他队列的纵向随访是重要的下一步。