An Ecological Comparison Study On The Causal Association Between Leptospirosis and Moyamoya Disease in Hubei, China, 2017-2019

Abstract Background and PurposeThe importance of environmental factors (especially leptospirosis) in moyamoya disease (MMD) has not been clarified. Here we investigated the epidemiological characteristics of MMD under perspective of ecology in Hubei province, China.MethodsWe conducted a population-based study to describe the epidemiologic characteristics of MMD in Hubei province between 2017 and 2019. The regional clusters of the hot spots (high incidence) and cold spots (low incidence) of MMD were identified using the spatial statistical method. To evaluate the role of leptospirosis in MMD, we performed an ecological comparison study to evaluate whether the socioeconomic and environmental variables of hot spots are more suitable for leptospirosis spread. Results The average annual age-adjusted incidence of MMD was 2.85 per 100 000 person-years from 2017 to 2019. The middle-aged had higher incidence of MMD than the children. There existed an obvious geographic distribution of MMD at county level that the average annual age-adjusted incidence of hot spots was about 8 times than the cold spots. The hot spots were identified mainly in the low mountainous and hilly terrain, while cold spots were located in the Jianghan Plains. Compared to cold spots, the hot spots had larger cattle density (28.9 vs 7.7, P=0.002), higher percentages of rice field (80.3% vs 35.7%, P=0.002), and lower elevation (33.6 vs 157.4, P=0.001)Conclusions We identified the obvious geographic distribution of MMD in the province, which initially strengthened the importance of environmental factors of this disease. Moreover, we preliminarily identified that people who lived in the low elevation regions with close contact to the cattle and rice field has a high risk of MMD. Future studies are needed to explore the potential environmental factors in MMD, especially for early-life exposure to leptospirosis.