| Objective:1.To investigate the association of family history of cardiovascular disease with ischemic stroke events in Mongolian population.2.To investigate the association of smoking with ischemic stroke events in Mongolian population.3.To investigate the cumulative effect of family history of cardiovascular disease and smoking on ischemic stroke events in Mongolian population.Subjects and Methods:1. Baseline investigation:A cross-sectional survey was conducted between 2002 and 2003, in which 2589 participants aged 20 years and older were recruited from 32 villages in 2 adjacent townships located in Kezuohou Banner(county) and Naiman Banner in Inner Mongolia. Written informed consent was obtained for all study participants, and they were administered interview using a standard questionnaire, and the related physical examination and blood samples collection were conducted by trained staffs. Data on demographic characteristics, family history of hypertension, smoking and alcohol consumption was obtained. Blood pressure, height, weight, waist circumference and hip circumference were measured for all participants according to standard methods. Fasting blood samples were taken in the morning and separated in the field, and then were sent to laboratory under low temperature and frozen at-80 ℃. Triglyceride(TG), total cholesterol(TC), and high-density lipoprotein cholesterol(HDL-C), and were detected for all participants.2. Follow-up survey: Since January 2004 to August 2012, continuous follow-up surveys were conducted for the 2589 subjects involved in the baseline study. The outcome event was defined as the first occurrence of ischemic stroke during the time from the baseline to the last follow-up. We interviewed the monitoring data and hospital medical records for the subjects who experienced a stroke by household to confirm the stroke events using standard questionnaires.3. Statistical analysis:Epidata3.0 software was used to establish a database, and all data was checked after data entry for two times. All statistical analyses were conducted using SAS 9.3 and SPSS 16.0 statistical software. All p-values were based on a 2-sided test and a significance level of 0.05.Results:1. A total of 2583 participants with baseline data completed the follow-up survey, including 1061 males(41.08%)and 1522 females(58.92%). There were 1278 people with no family history of cardiovascular disease/nonsmokers, including 292 males and 986 females. There were 158 people with family history of cardiovascular disease/nonsmokers, including 90 males and 68 females. There were 967 people with no family history of cardiovascular disease/smokers, including 543 males and 424 females. There were 180 people with family history of cardiovascular disease/smokers, including 136 males and 44 females.2. During the 9.2 years follow-up, 76 new ischemic stroke cases occurred, including 48 males and 28 females. The cumulative incidence rate of ischemic stroke were 2.9%.3. The Kaplan–Meier curves results showed that the cumulative incidence rate of ischemic stroke were 1.17%, 3.83%, 5.70% and 8.33% for no family history of cardiovascular disease/nonsmokers, no family history of cardiovascular disease/smokers, family history of cardiovascular disease/nonsmokers and family history of cardiovascular disease/smokers, respectively.4. By Cox proportional hazards model, in the case of not adjusting confounding factors, the HRs of family history of cardiovascular disease group and smoking group were 3.275 and 2.808,(all P<0.05), compared with the no family history of cardiovascular disease group and no smoking group, respectively. After multivariate adjustment, the HRs of family history of cardiovascular disease group and smoking group were 1.820(p=0.022)and 1.972(p=0.013), compared with the no family history of cardiovascular disease group and no smoking group, respectively.5. By Cox proportional hazards model,in the case of not adjusting confounding factors, the HRs for the participants without family history of cardiovascular disease/smokers, with family history of cardiovascular disease/nonsmokers, and with family history of cardiovascular disease/smokers compared with those without family history of cardiovascular disease/nonsmokers were 3.353, 5.092 and 7.890, respectively(all P<0.05). After multivariate adjustment, the HRs for the participants without family history of cardiovascular disease/smokers, and with family history of cardiovascular disease/smokers compared with those without family history of cardiovascular disease/nonsmokers were 2.256 and 2.449(all P<0.05).Conclusions:1.The cumulative incidence among the participants with family history of cardiovascular disease and smoking were significantly higher than among those without family history of cardiovascular disease group and without smoking in the study, respectively. The cumulative incidence of the group with family history of cardiovascular disease/smokers was significantly higher than the other groups.2.The family history of cardiovascular disease and smoking are risk factors for ischemic stroke in the study.3.Smoking may increase the risk of ischemic stroke events among the population with family history of cardiovascular disease. |
