Hiroshi Morimoto
Climate is one of the environmental factors which affect human health. Health risks associated with exposure to cold are well documented using methods of regression models. Besides, for cerebral infarction, regression models provided warning systems which were operated in several countries, using a threshold of temperature: If temperature decreases below (or increases over) the threshold, they provide a warning message (or safe message) on cerebral infarction in winter. However, if there are non-negligible high-risk cases with high temperature in winter, then this warning system therefore becomes highly dangerous. Exploring the features of weather patterns including warm cases becomes important in addition to the cases of cold exposure. In this study, we attempted to analyse the pattern of weather changes that affected the onset of cerebral infarction, paying attention to the cases of high risk and high temperature, and tried to suggest a mechanism of the onset of disease by exploring the data of expressions of DNA during particular changes of weather. We use Bayesian analysis as a method to explore the features of these high-risk cases. We identified a "cool and warming pattern" among high-risk cases for the incidence of cerebral infarction. This suggests a mechanism different from cold exposure, reaching the onset of cerebral infarction. At a DNA level, there is known a similar feature in the gene expression data for inflammatory DNA. We conclude that there is a common feature, cool and rewarming, between the change of weather and gene expressions. This finding will contribute to clarify a mechanism for the incidence of cerebral infarction.