Environmental selenium (Se) distribution in the US is uneven, yet US residents appear to have a relatively narrow range of serum Se concentrations, according to the NHANES III survey data; this is probably due to the modern food-distribution system. In the US, Se concentration in alfalfa leaves has been used as a proxy for regional Se exposure (low, medium or high, corresponding to ≤ 0.05, 0.06-0.10 and ≥ 0.11 ppm respectively). Se in plants, soil, water, and bacteria can be transformed into volatile dimethyldiselenide, which can be inhaled and excreted via the lung. Hence, pulmonary Se exposure may be different in states with different atmospheric Se levels. We found a significantly higher death rate from COVID-19 in low-Se states than in medium-Se or high-Se states, though the case densities of these states were not significantly different. Because inhaled dimethyldiselenide is a potent inducer of nuclear-factor erythroid 2 p45-related factor 2 (Nrf2), exposure to higher atmospheric dimethyldiselenide may increase Nrf2-dependent antioxidant defences, reducing the activation of NFκB by SARS-CoV-2 in the lung, thereby decreasing cytokine activation and COVID-19 severity. Atmospheric dimethyldiselenide may thereby play a role in COVID-19 mortality, although the extent of its involvement is unclear.

Synopsis

Loss of pulmonary dimethydiselenide via exhalation may help explain a significantly higher death rate from COVID-19 in states with low environmental (atmospheric) Se concentrations.

美国环境硒 (Se) 分布不均，但根据 NHANES III 调查数据，美国居民的血清硒浓度范围似乎相对较窄；这可能是由于现代食品分配系统。在美国，苜蓿叶中的 Se 浓度已被用作区域 Se 暴露的代表（低、中或高，分别对应 ≤ 0.05、0.06-0.10 和 ≥ 0.11 ppm）。植物、土壤、水和细菌中的硒可转化为挥发性二甲基二硒化物，可被吸入并经肺排出体外。因此，在不同大气硒水平的状态下，肺硒暴露可能不同。我们发现低硒州的 COVID-19 死亡率明显高于中硒州或高硒州，尽管这些州的病例密度没有显着差异。由于吸入的二甲基二硒化物是核因子红细胞 2 p45 相关因子 2 (Nrf2) 的有效诱导剂，因此暴露于较高大气中的二甲基二硒化物可能会增加 Nrf2 依赖性抗氧化防御，从而减少肺部 SARS-CoV-2 对 NFκB 的激活，从而降低细胞因子的激活和 COVID-19 的严重程度。因此，大气中的二甲基二硒化物可能在 COVID-19 死亡率中发挥作用，尽管其参与程度尚不清楚。

概要

通过呼气损失肺部二甲基二硒化物可能有助于解释在环境（大气）硒浓度低的州因 COVID-19 而导致的死亡率显着升高的原因。