A Cohort Study On The Association Between Physical Activity And All-Cause Mortality

ObjectivesThis study aimed to investigate the association between physical activity(PA)and all-cause mortality.MethodsAt baseline,20194 study participants(aged?18 years)were recruited by using a cluster random sampling method from rural areas of Xin'an County,Henan Province,China between July to August 2007 and July to August 2008.All participants completed the questionnaire survey and physical examination,and laboratory measurement.A total of 17265 participants(response rate 85.5%)were successfully performed the same as for the baseline examination and followed up from July to August 2013 to July to October 2014.After excluded 3 participants without PA data at baseline,our study included 17262 participants to explore the association between PA and all-cause mortality.According to PA level at baseline,Participants were divided into extremely light physical activity(ELPA)group,light physical activity(LPA)group,moderate physical activity(MPA)group,and heavy physical activity(HPA)group.Cox proportional hazards regression models and restricted cubic splines were used to estimate the risk of all-cause mortality in our study and different gender,age,drinking status,fasting plasma glucose(FPG)levels,blood pressure(BP)levels,body mass index(BMI)levels and serum lipid levels.Sensitivity analyses involved excluding participants who died within the previous 1 year at baseline,and further excluding participants who died within the previous 1 year at baseline and with prevalent cardiovascular diseases or cancer at baseline to test the robust of the results.Results1.During the follow-up period,1110 deaths occurred(death density:10.93 per 1000 person-years).Participants differed by survival status in sex,age,education level,income level,marital status,smoking status,drinking status,BMI,systolic blood pressure(SBP),diastolic blood pressure(DBP),FPG,and total cholesterol(TC),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)levels(all P<0.05).Participants differed by PA groups in sex,age,education level,income level,marital status,smoking status,drinking status,BMI,systolic blood pressure(SBP),diastolic blood pressure(DBP),FPG,and total cholesterol(TC),triglyceride(TG)and low-density lipoprotein cholesterol(LDL-C)levels(all P<0.05).2.The death density in the LPA,MPA and HPA groups were lower than that in the ELPA group,with the lowest death density in the HPA group in our study(all P<0.05).Cox proportional hazards regression models showed that compared with the ELPA group,LPA,MPA and HPA group have a lower risk of all-cause mortality after adjusting for baseline sex,age,education level,income level,marital status,smoking status,drinking status,BMI,SBP,FPG,TC,TG,HDL-C and LDL-C.The hazard ratio(HR)and 95%confidence interval(CI)were 0.62(0.53-0.72),0.61(0.51-0.73)and 0.51(0.41-0.62),respectively.Moreover,with the increase of PA level,the risk of all-cause mortality gradually decreased(all Ptrend<0.05).The results of sensitivity analyses were almost stable.3.Restricted cubic spline showed that after adjusting for possible confounding factors,a L-shaped was found of the association between PA level and all-cause mortality in our study(Pnonlinear<0.05).Compared with the PA level of 170 MET-h/week,the PA level of 420 MET-h/week reduced the risk of all-cause mortality by 39%(HR 0.61,95%CI 0.50-0.74).4.Interactions were assessed by multiplicative interactions terms in the Cox proportional hazards regression models and showed that PA level had multiple interaction with sex,age,drinking status,FPG levels,BP levels,BMI levels and serum lipid levels(all Pinteraction<0.05).5.In subgroups by sex,age,drinking status,BP levels,BMI levels,and serum lipid levels,after adjusting for the possible confounding factors,the risk of all-cause mortality was lower in the LPA,MPA,and HPA groups than that in the ELPA group.The results of sensitivity analysis were almost stable.Conclusions1.Compared with the ELPA group,the risk of all-cause mortality was significantly reduced in the LPA,MPA and HPA groups.2.The L-shaped was found of the association between PA level and all-cause mortality.Compared with the PA level of 170 MET-h/week,the PA level of 420 MET-h/week reduced the risk of all-cause mortality by 39%.3.PA level has a multiplier interaction with sex,age,drinking status,FPG level,BP level,BMI level and serum lipid level.After adjusting for the possible confounding factors,the subgroups of sex,age,drinking status,BP levels,BMI levels and serum lipid levels showed that the risk of all-cause mortality was lower in the LPA,MPA,and HPA groups than that in the ELPA group.