(1) Background: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease with still unknown etiology. Some occupational and environmental risk factors have been suggested, including long-term air pollutant exposure. We carried out a pilot case-control study in order to evaluate ALS risk due to particulate matter with a diameter of ≤10 µm (PM₁₀) as a proxy of vehicular traffic exposure. (2) Methods: We recruited ALS patients and controls referred to the Modena Neurology ALS Care Center between 1994 and 2015. Using a geographical information system, we modeled PM₁₀ concentrations due to traffic emissions at the geocoded residence address at the date of case diagnosis. We computed the odds ratio (OR) and 95% confidence interval (CI) of ALS according to increasing PM₁₀ exposure, using an unconditional logistic regression model adjusted for age and sex. (3) Results: For the 132 study participants (52 cases and 80 controls), the average of annual median and maximum PM₁₀ concentrations were 5.2 and 38.6 µg/m³, respectively. Using fixed cutpoints at 5, 10, and 20 of the annual median PM₁₀ levels, and compared with exposure <5 µg/m³, we found no excess ALS risk at 5–10 µg/m³ (OR 0.87, 95% CI 0.39–1.96), 10–20 µg/m³ (0.94, 95% CI 0.24–3.70), and ≥20 µg/m³ (0.87, 95% CI 0.05–15.01). Based on maximum PM₁₀ concentrations, we found a statistically unstable excess ALS risk for subjects exposed at 10–20 µg/m³ (OR 4.27, 95% CI 0.69–26.51) compared with those exposed <10 µg/m³. However, risk decreased at 20–50 µg/m³ (OR 1.49, 95% CI 0.39–5.75) and ≥50 µg/m³ (1.16, 95% CI 0.28–4.82). ALS risk in increasing tertiles of exposure showed a similar null association, while comparison between the highest and the three lowest quartiles lumped together showed little evidence for an excess risk at PM₁₀ concentrations (OR 1.13, 95% CI 0.50–2.55). After restricting the analysis to subjects with stable residence, we found substantially similar results. (4) Conclusions: In this pilot study, we found limited evidence of an increased ALS risk due to long-term exposure at high PM₁₀ concentration, though the high statistical imprecision of the risk estimates, due to the small sample size, particularly in some exposure categories, limited our capacity to detect small increases in risk, and further larger studies are needed to assess this relation.

中文翻译：

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肌萎缩性侧索硬化症的风险以及通过车辆交通暴露于颗粒物的风险：病例对照研究

（1）背景：肌萎缩性侧索硬化症（ALS）是一种进行性神经退行性疾病，病因仍未知。已经提出了一些职业和环境风险因素，包括长期接触空气污染物。我们进行了一项试点病例对照研究，以评估直径≤10 µm（PM ₁₀）的颗粒物引起的ALS风险，以作为车辆交通暴露的替代指标。（2）方法：在1994年至2015年之间，我们招募了ALS患者和对照，并转介给了Modena神经病学ALS护理中心。我们使用地理信息系统对PM _10进行了建模病例诊断之日起，由于地理编码住所地址的交通排放而产生的浓度。我们根据增加的PM ₁₀暴露量，使用针对年龄和性别调整的无条件逻辑回归模型，计算了ALS的优势比（OR）和95％置信区间（CI）。（3）结果：对于132名研究参与者（52例和80例对照），年平均PM ₁₀浓度和最大PM ₁₀浓度分别为5.2和38.6 µg / m ³。使用固定的临界点为年度中位数PM ₁₀水平的5、10和20 ，并且与暴露<5 µg / m ^3相比，我们发现在5–10 µg / m ^3下没有过量的ALS风险（或0.87，95％CI 0.39–1.96），10–20 µg / m³（0.94，95％CI 0.24–3.70）和≥20µg / m ³（0.87，95％CI 0.05-15.01）。根据最大的PM ₁₀浓度，我们发现暴露于10–20 µg / m ³（OR 4.27，95％CI 0.69–26.51）的受试者与暴露于<10 µg / m ^3的受试者相比，存在统计学上不稳定的过量ALS风险。但是，风险在20–50 µg / m ³（或1.49，95％CI 0.39–5.75）和≥50µg / m ³（1.16，95％CI 0.28–4.82）时降低。暴露于增加的三分位数中的ALS风险显示出相似的零关联，而将最高四分位数和最低三分位数相加在一起的比较显示，很少有证据表明PM ₁₀有过高风险浓度（OR 1.13，95％CI 0.50–2.55）。将分析限制在具有稳定住所的受试者之后，我们发现了基本相似的结果。（4）结论：在该初步研究中，我们发现有限的证据表明，由于高样本PM ₁₀浓度下的长期暴露而导致的ALS风险增加，尽管由于样本量小（尤其是在样本中），风险估计的统计不准确度很高。一些暴露类别，限制了我们发现风险小幅增加的能力，并且需要进一步的大型研究来评估这种关系。