Association between Physical Activity and Risk of All-cause Mortality in Middle-aged and Elderly People in China: a Prospective Cohort Study

Abstract

Background Insufficient physical activity is one of the most important public health problems in the 21st century and studies have found an association between physical activity and mortality. The effect of physical activity on mortality risk has attracted much attention in recent years, but few studies have reported the relationship between physical activity and all-cause mortality risk in different populations. Objective To explore the relationship between physical activity and all-cause mortality risk in middle-aged and older adults (45 years old and above) in China. Methods Based on the data of China Health and Retirement Tracking Survey (CHARLS) from 2011 to 2018, a total of 2 799 middle-aged and older adults from the 2011 baseline population of the CHARLS were selected as the research subjects on September 10, 2022, their baseline data such as demographic variables, lifestyle variables, and number of chronic diseases were collected, and physical activity level was evaluated based on the International Physical Activity Questionnaire (IPAQ) as low level physical activity〔600 metabolic equivalent (MET) /week) 〕, moderate level of physical activity (600-3 000 MET/week), high level of physical activity (3 000 MET/week). The follow-up period was from 2011 to 2018, and data from 2013, 2015 and 2018 were selected for follow-up, with all-cause death as the endpoint event, and the subjects were divided into the survival group (n=2 424) and all-cause death group (n=375) according to their survival status. Cox proportional hazard regression model was used to analyze the relationship between physical activity level and all-cause mortality risk in middle-aged and older adults, sensitivity analysis and stratification analysis were also performed. Results During the 7-year follow-up, 375 cases of all-cause death occurred among 2 799 middle-aged and older adults with the incidence of all-cause death of 13.40%. There were statistically significant differences in physical activity level, gender, age, marital status, education level, ADL limitation, BMI, smoking, alcohol consumption and the number of chronic diseases between the survival group and all-cause death group (P<0.05). After adjusting for confounding factors, multivariate Cox proportional hazard regression analysis showed that the risk of all-cause death was reduced by 43%〔HR=0.57, 95%CI (0.44, 0.75), P<0.001〕and 64%〔HR=0.36, 95%CI (0.27, 0.48), P<0.001〕in the middle-aged and older adults with low level of physical activity and high level of physical activity, respectively. The results of both sensitivity analyses showed a reduced risk of all-cause mortality in the middle-aged and older adults with moderate and high levels of physical activity compared with those with low level of physical activity (P<0.001), indicating that the results are robust. Stratified analysis showed that moderate level of physical activity could reduce the risk of all-cause death by 50%〔HR=0.50, 95%CI (0.33, 0.76), P<0.001〕in people aged 60-74 years and 51%〔HR=0.49, 95%CI (0.33, 0.73), P<0.001〕in people with normal BMI. High levels of physical activity were associated with a 74%〔HR=0.26, 95%CI (0.14, 0.47), P<0.001〕 and 65%〔HR=0.35, 95%CI (0.24, 0.51), P<0.001〕lower risk of all-cause death in people aged 45 to 59 and 60 to 74 years, respectively, and a 71%〔HR=0.29, 95%CI (0.20, 0.43), P<0.001〕and 64%〔HR=0.36, 95%CI (0.22, 0.59), P<0.001〕lower risk of all-cause death in people with normal BMI, overweight or obesity. Conclusion Both moderate and high levels of physical activity can reduce the risk of all-cause death in middle-aged and older adults, and the effect of high level of physical activity is more obvious. From the perspective of reducing the risk of all-cause death, it is suitable for people aged 45-59 years old, overweight and obese people to choose high level of physical activity. People aged 60-74 years and with normal BMI can benefit from moderate or high levels of physical activity. There is no clear recommendation with sufficient evidence for people aged≥75 years old and lean people, who should make decisions according to their own specific situations.

Keywords

• physical exertion|all-cause death|middle-aged and elderly people|charls|prospective cohort study