Abstract: Objective To explore the effect of total cholesterol (TC) longitudinal trajectory on the new onset ischemia stroke of the population over 50 years of age. Methods A prospective cohort study was conducted based on kailuan research cohort. The population over 50 years of age (n=23 830) with complete TC data in the first, second and third measurements and no history of stroke before the third measurement was used as the observation population. According to the TC longitudinal trajectory, three TC trajectory groups were determined: low-stable group (n=9 699, 40.70%), medium-stable group (n=11 723, 49.19%) and high-stable group (n=2 408, 10.10%). The cumulative incidences of ischemic stroke in different TC trajectory groups were compared by Kaplan-Meier method. Cox regression model was used to analyze the effect of TC longitudinal trajectory on the ischemic stroke of the population over 50 years of age. Results During the follow-up (6.89±0.72) years, the cumulative incidences of ischemic stroke in the different TC trajectory groups were 4.42%, 4.88% and 5.72%, respectively, and Log-rank test showed that the differences between the three groups were statistically significant (χ2=8.234, P＜0.05). Cox regression analysis showed that after adjusting for gender and other influencing factors, the HR values (95%CI) of ischemic stroke were 1.222 (1.062-1.407) and 1.400 (1.122-1.747) in medium-stable and high-stable groups compared with those of low-stable group. After adjusting for baseline TC and the TC change value, respectively, the elevated TC longitudinal trajectory level was also the risk factor for ischemic stroke. These trends persisted in people who did not take lipid-lowering drugs. However, there were no significant differences in the levels of TC longitudinal trajectory on ischemic stroke of patients taking drug. Conclusion The elevated TC longitudinal trajectory level is a risk factor for ischemic stroke in the population over 50 years of age, which is independent to the baseline single TC measurement and change value. The use of lipid-lowering drugs can reduce the influence of the increased longitudinal trajectory level of TC on ischemic stroke in the population over 50 years old.

Key words: cholesterol, stroke, risk factors, cohort studies, longitudinal trajectory