Background This study aimed to explore the impact of social activity frequency on mid- and long-term overall survival in older Chinese people.

Methods The association between social activity frequency and overall survival was analysed in 28 563 subjects from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) cohorts.

Results A total of 21 161 (74.1%) subjects died during the follow-up of 132 558.6 person-years. Overall, more frequent social activity was associated with longer overall survival. From baseline to 5 years of follow-up, adjusted time ratios (TRs) for overall survival were 1.42 (95% CI 1.21 to 1.66, p<0.001) in the not monthly but sometimes group, 1.48 (95% CI 1.18 to 1.84, p=0.001) in the not weekly but at least once/month group, 2.10 (95% CI 1.63 to 2.69, p<0.001) in the not daily but at least once/week group, and 1.87 (95% CI 1.44 to 2.42, p<0.001) in the almost everyday group versus never group. From 5 years to the end of follow-up, adjusted TRs for overall survival were 1.05 (95% CI 0.74 to 1.50, p=0.766) in the not monthly but sometimes group, 1.64 (95% CI 1.01 to 2.65, p=0.046) in the not weekly but at least once/month group, 1.23 (95% CI 0.73 to 2.07, p=0.434) in the not daily but at least once/week group, and 3.04 (95% CI 1.69 to 5.47, p<0.001) in the almost everyday group versus the never group. Stratified and sensitivity analysis revealed similar results.

Conclusion Frequent participation in social activity was significantly associated with prolonged overall survival in older people. However, only participating in social activity almost every day could significantly prolong long-term survival.