Reductions in under-5 mortality and public health improvements of the China Healthy Cities (Counties) initiative: a nationwide quasi-experimental study.

The China Healthy Cities (Counties) public health initiative has been at the forefront of China's efforts to counteract the growing challenges in the urban environment since the 1990s. It primarily focuses on improving the urban living environment. However, the nationwide health impacts of the initiative remain unexplored. We constructed nationwide county-level and city-level panel data from 1996 to 2012 using data on under-5 mortality rates (U5MR), the list of China healthy cities and counties and socioeconomic factors. We used a two-step staggered difference-in-differences approach that exploits variations in the timing of achieving the title of China Healthy City/County. Subgroup analyses by region were performed. We included 707 cities in the China Healthy Cities study, and 1631 counties in the China Healthy Counties study. Our results indicate substantial and significant reductions in U5MR associated with the public health initiative in China. The association varies across regions with different socioeconomic statuses. China Healthy Cities were significantly associated with a reduction of 0.7/1000 (95% CI -1.2 to -0.2) in under-5 mortality 5 years after cities gained the title and a decrease of 1.4/1000 (95% CI -2.2 to -0.6) 10 years afterward. Cities from western China saw the largest statistically significant gains with 3.2/1000 and 7.2/1000 reductions in child mortality after 5 and 10 years, respectively. China Healthy Counties were also associated with significant reductions in under-5 mortality 8 years after achieving the title; it was associated with 2.6/1000 reductions in under-5 mortality nationwide and 3.8/1000 reductions in eastern China. Our results are robust to heterogeneous treatment effects across cities/counties over time and various model specifications. Our results suggest significant reductions in under-5 mortality associated with this public health intervention focusing on living environment conditions. Future research could explore differential effects across regions and clarify the underlying causal mechanisms