Study On The Risk Factors Of Stroke Based On Nested Case-control Study

ObjectiveTo study the factors influencing the stroke based on nested case-control study,to explore the interaction of family history of stroke,physical activity,and hypertension on the incidence of stroke.MethodA total of 3894 subjects without stroke who were enrolled in the baseline survey in 2009 in Henan rural areas were selected in the cohort study.Then,the cohort subjects were followed up in 2014 for the first time.The subjects were divided into the case group and control group according the study on whether they have a stroke in five years.Finally,195 cases and 390 controls were enrolled in the nested case-control study.A Cox model was used by fitting a logistic model to study the risk factors of stroke.Multifactor dimensionality reduction software(MDR)was used to evaluate the environment factors interaction.Results1.General demographic characteristics in case and control The cohort of stroke included 3894 subjects,of which,3049 were followed up in 2014.The ratio of follow up was 78.30%.218 new stroke cases were found in the follow up(23 deaths for stroke).Finally,195 stroke cases were selected in the case group.Meanwhile,another 390 healthy persons with matched age and gender were selected as control group.There were 189 males accounting for 32.3% and 396 females accounting for 67.7% in this nested case control study.Subjects were main farmers.As regard educational level,most of the subjects were below the high school education.The proportion of subjects who drink alcohol was 16.41%,which was significant higher than control group(x~2=3.944,P =0.046).The proportion of having family history of hypertension in case group was significant higher than that in control group(x~2=10.629,P=0.002).Similarly,we also found the significant distribution of family history of stroke between case and control(x~2=15.32,P <0.001).Results of laboratory test showed that the plasma level of total cholesterol(TC)and triglyceride(TG)in stroke patients was significantly greater than that in control subjects.Physical examination showed that the BMI,waist-height ratio,systolic blood pressure,diastolic blood pressure and waist circumference of stroke cases were higher than that of controls.2.Analysis of risk factors of stroke incidence 1:2 matching single factor analysis displayed that compared with the primary school and below the level of education,the level of high school education was the protective factor(OR=0.45,95%CI: 0.24~0.84).Compared with subjects with income of 1000 yuan and below,subjects with 1000-3000 income levels of the population were at risk of stroke reduction(OR=0.35,95%CI: 0.12~0.99).Compared with no drinking subjects,drinking population had a high risk of stroke(OR=2.14,95% CI: 1.04~4.42).Participants with no family history of hypertension disease were more likely to be stroke(OR=1.79,95%CI:1.25~2.57).People with a family history of high blood lipids disease were also susceptible to stroke,compared with those without family history of high blood lipids(OR=1.79,95%CI: 1.25~2.57).Similarly,family history of stroke was also a risk factor of stroke incidence.Results of single factor regression analysis of the history of personal disease and stroke showed that the risk of stroke in patients with high cholesterol was 2.14 times higher than that of patients with non high cholesterol(95%CI: 1.26~3.63).The risk of stroke significantly increased in patients with abdominal obesity.Compared with non hypertensive patients,the risk of stroke in patients with hypertension increased 1.94 times(OR=2.94,95%CI:2.02~4.28).Similarly,subjects with metabolic syndrome more likely to be stroke(OR=2.42,95%CI: 1.64~3.55).Compared with the subjects with normal weight,subjects who were overweight tend to be stroke(OR=2.10,95%CI: 1.38~3.19),and the risk of stroke in obesity also increased(OR=2.80,95%CI: 1.74~4.50).3.The result of interaction analysis Multifactor dimensionality reduction model analysis showed that model including family history of stroke,physical activity and disease history of hypertension was the optimal interaction model.The test sample accuracy,sample test accuracy and cross validation consistency was 0.6551,0.6415,9/10 respectively.Multiplicative interaction analysis found that physical activity and family history of stroke may have a significant interaction in the stroke(OR=2.18,95% CI: 1.51~3.15).There was also a notable multiplicative interaction between hypertensive disease history and family history of stroke on the incidence of stroke(OR=4.66,95% CI: 2.35~9.26).Conclusion1.Drinking,family history of hypertension,family history of hyperlipidemia,family history of stroke,abdominal obesity,overweight and obesity,hypertension,metabolic syndrome are risk factors for stroke,which can increase the risk of stroke.2.Drinking,family history of stroke,history of hypertension,overweight and obesity are the independent risk factors of stroke.3.There is a significant interaction among family history of stroke,hypertension,physical activity,in the occurrence of stroke.