Evaluation of the effect of temperature on the incidence of ischemic stroke based on distributed lag non-linear model

ObjectiveTo explore the effect of temperature on the incidence of ischemic stroke in residents.

MethodsThe incidence and meteorological data of ischemic stroke from 2013 to 2020 in Pingyi county sub-cohort of Shandong Ecological cohort were collected. The distributed lag non-linear model (DLNM) was used to analyze the influence of temperature on the incidence of ischemic stroke in the whole population. In addition, the differences between genders and ages were also discussed.

ResultsA total of 50 427 people were observed from 2013 to 2020, and the number of cases of ischemic stroke was 42 014, with an average daily incidence of 14 cases. It was found that there was a non-linear relationship between the average daily temperature and the incidence of ischemic stroke. High temperature was related to the increase of the incidence of ischemic stroke, and high temperature had immediate effect and lag effect on the incidence of ischemic stroke. The cumulative relative risk(RR) of high temperature lag in 0-10 days was 1.433 (95%CI: 1.079-1.902). Low temperature and lower temperature had a certain protective effect on the whole population in a specific cumulative period, and the protective effect became weaker and weaker with the passage of time. The RR of low temperature and lower temperature lagging in 0-10 days were 0.618 (95%CI: 0.455-0.840) and 0.712 (95%CI: 0.608-0.834), respectively. The results of stratified analysis showed that high temperature had a great influence on the incidence of ischemic stroke in men and ≥ 65 years old group. When the accumulation of high temperature lagged for 10 days, the risk of ischemic stroke in the male group was the highest, with an RR of 1.678 (95%CI: 1.193-2.361), while for the group aged ≥ 65 years old, the relative risk of ischemic stroke reached the highest on the day of high temperature, with an RR of 1.523 (95%CI: 1.203-1.928).

ConclusionsThe temperature has a non-linear relationship with the incidence of ischemic stroke in residents. The high temperature will increase the risk of ischemic stroke in residents, and the cumulative lag effect is greater. Therefore, residents should pay attention to raising awareness of self-protection in hot weather.