The intensive use of pesticides has attracted great attention from the Chinese government. However, current regulations have had limited influence on their safe use. Although the acute neurologic effects of pesticides have been well documented, little is known about their cumulative effects. Knowledge of the impact of pesticides on health may convince farmers to minimize their use. We conducted a cross-sectional study in three provinces of China to evaluate the relationship between pesticide exposure and neurological dysfunction. Crop farmers were divided into two groups depending on their level of pesticide exposure. A total of 236 participants were assessed by questionnaire and neurological examination for symptoms and signs of neuropathy. Characteristics of neurologic dysfunction following cumulative low-level exposure were assessed with logistic regression analysis. Farmers exposed to high-level pesticide use had greater risk of developing sensations of numbness or prickling (odds ratio (OR) 2.62, 95% confidence interval (CI): 1.08–6.36). After adjusting for recent exposure, the risk of numbness or prickling symptoms (OR 2.55, 95% CI: 1.04–6.25) remained statistically significant. Loss of muscle strength and decreased deep tendon reflexes had OR > 2, however, this did not reach statistical significance. These findings suggest that overuse of pesticides increased risk of neurologic dysfunction among farmers, with somatosensory small fibers most likely affected. Measures that are more efficient should be taken to curb excessive use of pesticides.

The choroid plexus (CP), an important structure involved in cerebrospinal fluid (CSF) circulation, plays a key role in clearing harmful metabolites from the brain. However, the relationship between CP and the development of Parkinson's disease (PD) remains unclear, especially in those with freezing of gait (FOG). We aim to investigate the association between the CP area and CP/lateral ventricle area (CP/Ven) index with clinical symptoms of PD and the development of FOG. Seventy-three patients with PD (17 with FOG and 56 without FOG) and 49 healthy controls (HCs) underwent 7 T magnetic resonance imaging and neurological assessments. The CP area and CP/Ven index were calculated, and the differences across groups were compared. Spearman's rank correlation was used to evaluate associations between these indices and clinical scales. Binary logistic regression was used to explore the impact of the CP area and CP/Ven index on FOG occurrence in PD. Patients with FOG (PD-FOG) exhibited significantly higher CP area and CP/Ven index than those without FOG (PD-nFOG). Both the CP area and CP/Ven index were positively correlated with the PD motor scale scores, especially postural instability/gait disturbance. Receiver operating characteristic curve analysis showed that the CP area and CP/Ven index effectively distinguished PD-FOG from PD-nFOG, with area under curve of 0.887 and 0.854, respectively. Logistic regression analysis confirmed that both indices independently increased the risk of FOG in PD. Elevated CP area and CP/Ven index are novel, noninvasive neuroimaging markers of FOG in PD.