Circadian variations in the occurrence of first‐ever intracerebral hemorrhage from different sources of income: a hospital‐based cross‐sectional study

BACKGROUND: The onset time of intracerebral hemorrhage (ICH) may be closely related to the working style and living habits of people, which are determined by different income sources in China. Therefore, the purpose of our study was to investigate the Circadian Variations in the occurrence of ICH from different sources of income. METHODS: This retrospective study enrolled 4,327 patients with first-ever ICH. Based on the time of day at which the patients developed symptoms, the classifiable onset time was assigned to one of eight three-hour intervals. And based on different income sources, they were categorized into three groups: Farmers, Wage-earners, and Freelancers. Demographic and risk factors of patients were then summarized, and the circadian variation of the 3 groups of patients’ known time of onset and those stratified by sex and age were analyzed. RESULTS: The frequency of ICH onset exhibited significant circadian variation among the 3 income groups, demonstrating a bimodal distribution in the daytime, with a nadir during the night (all P < 0.001). Three groups showed a significant initial peak between 06:01 and 09:00, and the same peak was observed in their subgroups of sex and age. In the 3 income source groups, there was a smaller second peak that between 15:01 and 18:00 for Farmers and Wage-earners and 18:01 and 21:00 for Freelancers. After stratification by sex and age, the second peak was between 18:01 and 21:00 for female in Farmers, female in Freelancers, under 65 years of age in Wage-earners and 65 years or older in Freelancers, while 15:01 and 18:00 for the other groups. CONCLUSIONS: Different circadian variations of ICH onset time are found in patients with different income sources in southwest China’s Chongqing Municipality cohort. Moreover, the frequency and distribution pattern of peak hours may be closely related to the working style and living habits of people with different income sources.