[Study of association of sedentary time and physical activity with development of chronic obstructive pulmonary disease in non-smoking women aged 40 years and above in Songjiang District, Shanghai].

Objective: To analyze the association of sedentary time and physical activity with the risk of developing chronic obstructive pulmonary disease (COPD) in non-smoking women aged 40 years and above in Songjiang District, Shanghai. Methods: Based on a natural population-based cohort in Songjiang, a total of 18 707 non-smoking women who were aged 40 years and above and without COPD at baseline survey were enrolled in the study. Cox proportional risk regression model was used to analyze the associations of the duration of sedentary behavior, physical activity with the risk for COPD at baseline survey, and the hazard ratio (HR) of risk for COPD and its 95%CI were calculated. Stratified analyses were performed based on age, BMI, history of respiratory diseases and so on. Sensitivity analyses were conducted by excluding the cases diagnosed with COPD within one year after the baseline survey. Results: As of March 31, 2024, a total of 691 new COPD cases had been recorded after a median follow-up time of 6.96 years with an incidence density of 53.22 per 10 000 person-years. After adjusting for relevant confounders, in the tertile subgroups of sedentary time, the risk for COPD reduced by 17% in the short sedentary time group compared with the long sedentary time group (HR=0.83,95%CI:0.70-0.99). Compared with the low physical activity level and long sedentary time group, the risk for COPD reduced by 24% in the high physical activity level and short sedentary time group (HR=0.76, 95%CI: 0.61-0.95) and by 23% in the low physical activity level and short sedentary time group (HR=0.77, 95%CI: 0.60-0.97). Compared with the non-physical exercise and long sedentary time group, the risk for COPD reduced by 28% in the non-physical exercise and short sedentary time group (HR=0.72, 95%CI: 0.60-0.87). These associations remained when the cases diagnosed with COPD within one year of the baseline survey were excluded. Conclusions: Increasing physical activity and reducing sedentary time have beneficial effects to prevent COPD in non-smoking women, and reducing sedentary time alone may also reduce the risk for COPD if increasing physical exercise or other physical activity is not possible.