A Prospective Cohort Study On The Association Between Physical Activity And Risk Of The Cardiovascular Disease Among Hypertensive Patients

Background and objectsCardiovascular disease(CVD)has become one of the major diseases threatening human health and was the leading cause of mortality across the world over the last 15years.Physical activity(PA)has profound benefits in lowering cardiovascular morbidity and mortality.Currently,there is scant literature that explicitly examined the association between PA and CVD risk in hypertensive patients.This study aims to explore the association and dose-response relationship between PA and risk of CVD,and mediation effect of obesity indexes on association between PA and CVD,which will provide a scientific basis for the prevention and treatment of CVD in hypertensive patients.Subjects and methodsParticipants in this study came from 53,269 subjects aged 30～79 years from China Kadoorie Biobank(CKB)study in Wuzhong District of Suzhou City,Jiangsu Province.The baseline survey was conducted from November of 2004 to January of 2008 and participants were followed up to December 31,2017.The data was from baseline and follow-up surveys.The baseline survey included questionnaire,clinical measurements,and random blood glucose measurement.The questionnaire collected information on demographic data,personal health behaviors(including PA)and general health related data,etc.The outcome information was regularly collected through several ways such as Disease Surveillance Points(DSP)system death registry and national health insurance system.Hypertensive patients were selected in this study,those with CVD or cancer at baseline,PA outliers,and had missing values were excluded for this analysis,leaving final 20,183 participants for analysis.1.Cox proportional hazards regression models and restricted cubic spline models were used to estimate the association of PA with the risk of coronary heart disease(CHD)and stroke.The total PA was divided into four sub-groups based on quartiles for analysis(Q1～Q4)and we explored the relationship between different domains or intensities of PA and CVD risk.2.Logistic regression using KHB method was conducted to investigate the mediation effect of obesity indexes on association between daily total PA and CHD or stroke.Results1.The entire study population accumulated 218,725.8 person-years of follow-up,and the mean follow-up time was 11.1 years.The incidence density of CHD was401.4/100,000 person-years with a mean age of 69.8±8.7 years,and the incidence density of stroke was 830.7/100,000 person-years with a mean age of 62.7±8.2 years.In association of PA level and incident of CHD,compared with those in Q1 group,the adjusted HRs(95%CIs)for those with baseline 0.67(0.55～0.83)and 0.61(0.48～0.77)respectively,and the protective effects were similar in different genders.The association above was still significant in participants aged 60～69,BMI<24 kg/m~2,current smoker or not,non-weekly drinker,sedentary time<3 h/d,stage 1 and 2hypertension,and without diabetes.In association with PA level and incident of stroke,compared with participants who had the lowest level of PA(Q1),those with PA in Q3group had a 19%lower risk of stroke(HR=0.81,95%CI:0.71～0.93).The association only exists in males(HR=0.75,95%CI:0.61～0.93)after gender stratification.Further analysis in subgroups showed that the association above was still significant in participants with BMI<24 kg/m~2,current smoker or not,non-weekly drinker,stage 1and 3 hypertension,and without diabetes.In the association of different domains and intensities of PA with the incidence of CVD,higher level of work-related and commuting activities,and higher level of moderate and vigorous intensities of PA were associated with decreased risk of CHD and stroke.Cubic spline graphs showed an inverse association between PA level and CHD risk(Non-linear test,?~2=0.50,P=0.779).Non-liner association of PA level and stroke risk(Non-linear test,?~2=12.85,P=0.002)was observed.The HRs between PA and risk of stroke showed a U-shaped,which suggests that a higher level of PA(>34 MET-h/d)could decrease the protective effect.2.The means of BMI and body fat percentage(BFP)of women with hypertension were higher than men,and the mean of waist circumference(WC)of men was higher than women.The mediation analysis indicated that the obesity index(WC and BMI)played a part role in the mediation effect in the association of daily total PA and risk of CHD.After adjusting for the confounding factors,the proportion of mediating effect of WC and BMI was 4.84%and 2.55%.The obesity index had a partial mediating effect in women after gender stratification and the mediating effect of WC,BMI,and BFP was 7.18%,4.94%and 4.29%,respectively.There was no mediating effect observed in men.The mediating effect of obesity indexes was not found in the relationship between daily total PA and stroke in hypertensive people.Conclusions1.There was an inverse relationship between PA level and risk of CVD in hypertensive patients.The higher level of daily total PA was associated with a lower risk of CHD.While the dose-response relationship of PA and stroke revealed the U-shape,which indicated that the protective effect decrease with high level of PA.2.The obesity index had a partial mediation effect in the association of daily total PA and risk of CHD in hypertensive individuals.Hypertensive people should strengthen the lifestyle intervention,improve PA level and maintain a healthy weight to decrease the risk of CHD.